10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the Year Ended December 31, 2014

OR

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

Commission File Number 000-51531

SUNESIS PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware	94-3295878
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification Number)

395 Oyster Point Boulevard, Suite 400

South San Francisco, California 94080

(Address of principal executive offices, including zip code)

(650) 266-3500

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class:	Name of Each Exchange on Which Registered:
Common Stock, par value $0.0001 per share	The NASDAQ Stock Market LLC

Securities registered pursuant to Section 12(g) of the Act:

None

(Title of Class)

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, accelerated filer, a non-accelerated filer or a smaller reporting company. See definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer	¨	Accelerated filer	x
Non-accelerated filer	¨  (Do not check if a smaller reporting company)	Smaller reporting company	¨

Indicate by check mark whether the registrant is a shell company (as defined in Exchange Act Rule 12b-2.)    Yes  ¨    No  x

The aggregate market value of common stock held by non-affiliates of the registrant, based on the closing sales price for such stock on June 30, 2014, as reported by The Nasdaq Stock Market, was $263,889,528. The calculation of the aggregate market value of voting and non-voting stock excludes 19,847,977 shares of the registrant’s common stock held by current executive officers, directors and stockholders that the registrant has concluded are affiliates of the registrant. Exclusion of such shares should not be construed to indicate that any such person possesses the power, direct or indirect, to direct or cause the direction of the management or policies of the registrant or that such person is controlled by or under common control with the registrant.

The total number of shares outstanding of the registrant’s common stock, $0.0001 par value per share, as of February 27, 2015, was 67,739,771.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Definitive Proxy Statement, to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the 2015 Annual Meeting of Stockholders of Sunesis Pharmaceuticals, Inc. (hereinafter referred to as “Proxy Statement”) are incorporated by reference in Part III of this report. Such Proxy Statement will be filed with the Securities and Exchange Commission not later than 120 days after the conclusion of the registrant’s year ended December 31, 2014.

SUNESIS PHARMACEUTICALS, INC.

TABLE OF CONTENTS

		Page No.
	PART I
ITEM 1.	Business	3
ITEM 1A.	Risk Factors	21
ITEM 1B.	Unresolved Staff Comments	34
ITEM 2.	Properties	34
ITEM 3.	Legal Proceedings	34
ITEM 4.	Mine Safety Disclosures	34
	PART II
ITEM 5.	Market For Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	35
ITEM 6.	Selected Financial Data	37
ITEM 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	38
ITEM 7A.	Quantitative and Qualitative Disclosures About Market Risk	46
ITEM 8.	Financial Statements and Supplementary Data	48
ITEM 9.	Changes in and Disagreements With Accountants on Accounting and Financial Disclosure	69
ITEM 9A.	Controls and Procedures	69
ITEM 9B.	Other Information	71
	PART III
ITEM 10.	Directors, Executive Officers and Corporate Governance	72
ITEM 11.	Executive Compensation	72
ITEM 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	72
ITEM 13.	Certain Relationships and Related Transactions, and Director Independence	73
ITEM 14.	Principal Accounting Fees and Services	73
	PART IV
ITEM 15.	Exhibits, Financial Statement Schedules	74
	Signatures	75
	Exhibit Index	76

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PART I

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This report, including the information we incorporate by reference, contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the Private Securities Litigation Reform Act of 1995, which involve risks, uncertainties and assumptions. All statements, other than statements of historical facts, are “forward-looking statements” for purposes of these provisions, including without limitation any statements relating to our strategy, including regulatory plans to file a marketing authorization application with the European Medicines Agency, our preliminary analysis, assessment and conclusions of the results of the VALOR trail, and the commercial potential of vosaroxin, presenting clinical data and initiating clinical trials, our future research and development activities, including clinical testing and the costs and timing thereof, sufficiency of our cash resources, our ability to raise additional funding when needed, any statements concerning anticipated regulatory activities or licensing or collaborative arrangements, our research and development and other expenses, our operations and legal risks, and any statement of assumptions underlying any of the foregoing. In some cases, forward-looking statements can be identified by the use of terminology such as “anticipates,” “believe,” “continue,” “could,” “estimates,” “expects,” “intend,” “look forward,” “may,” “seeks,” “plans,” “potential,” or “will” or the negative thereof or other comparable terminology. Although we believe that the expectations reflected in the forward-looking statements contained herein are reasonable, there can be no assurance that such expectations or any of the forward-looking statements will prove to be correct, and actual results could differ materially from those projected or assumed in the forward-looking statements. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of many factors, including but not limited to those set forth under “Risk Factors,” and elsewhere in this report. We urge you not to place undue reliance on these forward-looking statements, which speak only as of the date of this report. All forward-looking statements included in this report are based on information available to us on the date of this report, and we assume no obligation to update any forward-looking statements contained in this report.

In this report, “Sunesis,” the “Company,” “we,” “us,” and “our” refer to Sunesis Pharmaceuticals, Inc. and its wholly-owned subsidiaries, except where it is made clear that the term refers only to the parent company.

ITEM 1. BUSINESS

General

We are a biopharmaceutical company focused on the development and commercialization of our pipeline of new oncology therapeutics for the potential treatment of solid and hematologic cancers. Our most advanced program is QINPREZO^TM (vosaroxin), our product candidate for the potential treatment of acute myeloid leukemia, or AML. Vosaroxin is an anticancer quinolone derivative, or AQD—a class of compounds that has not been used previously for the treatment of cancer. We have built a highly experienced cancer drug development organization committed to advancing vosaroxin in multiple indications to improve the lives of people with cancer.

In October 2014, we announced the results of a Phase 3, multi-national, randomized, double-blind, placebo-controlled trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory AML, or the VALOR trial. The VALOR trial, which enrolled 711 adult patients, was designed to evaluate the effect of vosaroxin in combination with cytarabine, a widely used chemotherapy in AML, on overall survival as compared to placebo in combination with cytarabine, and was conducted at 124 study sites in the U.S., Canada, Europe, South Korea, Australia and New Zealand. Patients treated with vosaroxin achieved increased overall survival compared to those treated with placebo (7.5 months vs 6.1 months, HR=0.87), the primary endpoint, but this difference did not achieve statistical significance (p=0.06). The complete remission (CR) rate, the sole secondary efficacy endpoint in the trial, did demonstrate a significant difference for the vosaroxin combination arm (30.1% vs 16.3%, p < 0.0001). Detailed results of the VALOR trial were presented in the "Late Breaking Abstracts" session of the American Society of Hematology (ASH) Annual Meeting in December 2014 and are summarized in the “Vosaroxin Clinical Trials in AML” section below.

Based on the results of the VALOR trial, we have submitted a letter of intent to the European Medicines Agency, or EMA, describing our intention to file a marketing authorization application, or MAA, for marketing authorization of vosaroxin plus cytarabine for the treatment of relapsed or refractory AML. We plan to meet with European regulatory authorities in preparation for an MAA filing in the second half of 2015.We are also currently engaged in discussions with the U.S. Food and Drug Administration, or FDA, to determine a potential regulatory path forward in the United States.

In the second half of 2013, we announced the initiation of three Phase 1/2 investigator-sponsored trials of vosaroxin, either as a standalone therapy or in combination with approved compounds, in various indications of AML and high-risk myelodysplastic syndrome, or MDS. The trials are being conducted at the University of Texas MD Anderson Cancer Center, or MDACC, Weill Cornell Medical College and New York-Presbyterian Hospital, and the Washington University School of Medicine.

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In December 2014, updated results from the ongoing Phase 1b/2 MDACC-sponsored trial of vosaroxin in combination with decitabine in older patients with previously untreated AML and high-risk MDS were presented at the ASH Annual Meeting. This trial is expected to enroll up to a combined total of approximately 70 patients.

We own worldwide development and commercialization rights to vosaroxin. In 2009, vosaroxin received orphan drug designation for the treatment of AML from the FDA and in 2012, the European Commission granted orphan drug designation to vosaroxin for the treatment of AML, which may provide for 10 years of marketing exclusivity in all member countries of the European Union following a product approval for this indication in Europe. In 2011, the FDA granted fast track designation to vosaroxin for the potential treatment of relapsed or refractory AML in combination with cytarabine. We have been granted, or notified of allowance of, a number of key patents for vosaroxin, details of which are provided in the “Intellectual Property” section below.

In January 2014, we announced the expansion of our oncology franchise through separate global licensing agreements for two preclinical kinase inhibitor programs. The first agreement, with Biogen Idec MA, Inc., or Biogen Idec, is for global commercial rights to SNS-062, a selective non-covalently binding oral inhibitor of Bruton’s tyrosine kinase, or BTK. BTK is a mediator of B-cell receptor signaling that is integral to the pathogenesis of B-cell malignancies. With preclinical characteristics and activity distinct from compounds in the same class, SNS-062 may hold potential as a differentiated treatment for B-cell malignancies and other blood cancers. We are currently conducting IND-enabling studies for SNS-062, with a view to filing an IND application with the FDA.

The second agreement, with Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, or Millennium, is for global commercial rights to several potential first-in-class, pre-clinical inhibitors of the novel target phosphoinositide-dependent kinase-1, or PDK1. PDK1 is a key kinase and mediator of PI3K/AKT signaling, a pathway involved in cell growth, differentiation, motility and survival. PDK1 inhibitors are expected to have unique effects on survival and invasion signaling and to be broadly active in both hematologic and solid tumor malignancies. In 2014, we selected two PDK1 inhibitors, SNS-229 and SNS-510, of which we plan to take at least one into IND-enabling absorption, distribution, metabolism and excretion, or ADME, and safety studies in 2015.

Both BTK and PDK1 programs were originally developed under a research collaboration agreement between Biogen Idec and Sunesis. In 2011, the PDK1 program was purchased by and exclusively licensed to Millennium along with the more advanced program, MLN2480, a pan-RAF inhibitor currently in the maximum tolerated dose cohort expansion stage of a Millennium Phase 1, multicenter dose escalation study. We currently expect SNS-062 and the PDK1 inhibitors will be developed exclusively by Sunesis.

Our Strategy

We plan to continue to build Sunesis into a leading biopharmaceutical company focused on the development and commercialization of new oncology therapeutics for the treatment of solid and hematologic cancers by:

· pursuing regulatory approval for vosaroxin as a potential treatment for relapsed or refractory AML in Europe, the United States, and other major markets;

· building a commercial infrastructure in order to promote and market vosaroxin in the United States as a treatment for AML;

· leveraging potential partners and distributors to commercialize vosaroxin in selective international markets;

· establishing vosaroxin as the new standard of care for patients with relapsed or refractory AML;

· exploring the broader potential of vosaroxin, beyond our pivotal indication, in different patient segments within AML and MDS through investigator sponsored trials;

· investing in additional clinical testing to evaluate vosaroxin for additional AML indications, MDS, other hematologic malignancies and solid tumors;

· leveraging our strong intellectual property protection over vosaroxin to capitalize on its full potential;

· supporting our multi-kinase inhibitor programs with Millennium in oncology and Biogen Idec for immunology indications;

· conducting IND-enabling studies for our BTK inhibitor, SNS-062, with a view to filing an IND application with the FDA;

· taking at least one of the two selected development candidates from our PDK1 inhibitor program, SNS-229 and SNS-510, into IND-enabling ADME and safety studies in 2015; and

· continuing to expand and develop our oncology-focused pipeline through further licensing or collaboration arrangements and research and development.

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Development Pipeline

The following chart summarizes our development pipeline:

Vosaroxin

Background. Vosaroxin is an AQD—a class of compounds that has not been used previously for the treatment of cancer. Preclinical data demonstrate that vosaroxin both intercalates DNA and inhibits topoisomerase II, an enzyme critical for cell replication, resulting in replication-dependent, site-selective DNA damage, G2 arrest and apoptosis. We licensed worldwide development and commercialization rights to vosaroxin from Sumitomo Dainippon Pharma Co., Ltd., or Sumitomo, in 2003.

Mechanism of Action. The molecular core of vosaroxin is structurally similar to quinolones and distinct from anthracyclines and anthracenediones. Vosaroxin's anticancer activity results from apoptosis caused exclusively by DNA intercalation, inhibition of topoisomerase II, and cell cycle inhibition in replicating cells.

Vosaroxin’s cytotoxic activity is established in diverse human tumors and clinical activity is observed in both solid and hematologic malignancies. In preclinical studies, vosaroxin demonstrated broad antitumor activity and exhibited additive or synergistic activity when combined with several therapeutic agents currently used in the treatment of cancer, including cytarabine. Vosaroxin maintains activity in drug resistant tumor cell lines and human tumor models. Vosaroxin evades P-gp transporter-mediated resistance, and its activity is p53 independent, reducing resistance to therapy. Vosaroxin has demonstrated anticancer activity in patients who have failed other topoisomerase II inhibitor treatment.

Development Opportunity. Our goal is to establish vosaroxin in combination with cytarabine as the standard of care for patients with relapsed or refractory AML. Additionally, we are exploring the broader potential of vosaroxin in different patient segments within AML and MDS through investigator-sponsored trials. Based on the outcome of regulatory interactions related to our VALOR trial, the results of investigator-sponsored trials, competitive concerns, our financial resources and various other factors, we may further invest in the development and clinical testing of vosaroxin for related disease areas and indications such as other AML populations, MDS, other hematologic malignancies and solid tumors.

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Vosaroxin Company-Sponsored Clinical Trials in AML

VALOR. In December 2010, we commenced enrollment of the VALOR trial, a Phase 3, randomized, double-blind, placebo-controlled, pivotal clinical trial of vosaroxin in combination with cytarabine to evaluate overall survival in patients with relapsed or refractory AML. The trial, which enrolled 711 adult patients, was conducted at 124 study sites in the U.S., Canada, Europe, South Korea, Australia and New Zealand. Patients were stratified for age, geographic region and disease status and randomized one to one to receive either vosaroxin and cytarabine or placebo and cytarabine. In October 2014, we announced the results from the VALOR trial, and further detail was presented in the "Late Breaking Abstracts" session of the American Society of Hematology (ASH) Annual Meeting in December 2014.

Patients treated with vosaroxin achieved increased overall survival compared to those treated with placebo (7.5 months vs 6.1 months, HR=0.87), the primary endpoint, but this difference did not achieve statistical significance (p=0.06). The complete remission (CR) rate, the sole secondary efficacy endpoint in the trial, did demonstrate a significant difference for the vosaroxin combination arm (30.1% vs 16.3%, p < 0.0001).

In a pre-planned analysis accounting for the stratification factors at randomization, a significant improvement in overall survival was demonstrated (HR=0.83, p=0.02). The pre-planned analysis of all treatment strata included the following poor-prognosis patient categories: over 60 years old (7.1 months vs 5.0 months, HR=0.75, p=0.003, n=451), refractory disease (6.7 months vs 5.0 months, HR=0.87, p=0.23, n=301), and early relapsed disease (6.7 months vs 5.2 months, HR=0.77, p=0.04, n=256). Outcomes in patients under 60 years old or with late relapsed disease were comparable between treatment arms, with no improvement in overall survival. Across all strata, the CR and Composite CR (CR+CRp+CRi) rates were higher in the vosaroxin combination arm.

Given the complexity of interpreting the impact of transplantation therapy, a predefined analysis of overall survival censoring for hematopoietic stem cell transplantation was planned. In this analysis, patients receiving the vosaroxin combination had a median overall survival of 6.7 months versus 5.3 months for patients receiving placebo and cytarabine (HR=0.81, p=0.02).

Regarding drug safety, Grade 3 or higher non-hematologic adverse events that were more common in the vosaroxin combination arm were gastrointestinal and infection-related toxicities, consistent with those observed in our previous clinical trials. The rate of serious adverse events was 55.5% in the vosaroxin combination arm compared to 35.7% in the placebo and cytarabine arm. 30-day and 60-day all-cause mortality were comparable between the trial arms (7.9% versus 6.6% and 19.7% versus 19.4%, for the vosaroxin combination versus placebo and cytarabine, respectively).

Phase 2 Combination.  The results from our completed Phase 1b/2 clinical trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory AML were published in the November 7, 2014 Ahead of Print issue of Haematologica. The article, titled “A Phase 1b/2 study of combination vosaroxin and cytarabine in patients with relapsed or refractory acute myeloid leukemia,” is available online at: http://www.haematologica.org/content/early/recent.

The Phase 1b/2 study assessed the safety and tolerability of vosaroxin in combination with cytarabine in patients with relapsed or refractory AML. Escalating vosaroxin doses (10-minute infusion; 10-90 mg/m² on days 1, 4) were given in combination with cytarabine on one of two schedules: schedule A (24-hour continuous intravenous infusion, 400 mg/m² per day on days 1-5) or schedule B (2-hour intravenous infusion, 1 g/m² per day on days 1-5). Following dose escalation, enrollment was expanded at the maximum tolerated dose. The maximum tolerated dose for schedule A was vosaroxin 80 mg/m² (dose-limiting toxicities: grade 3 bowel obstruction and stomatitis); the maximum tolerated dose was not reached for schedule B (recommended phase 2 dose: 90 mg/m²).

The median age in the study was 60 years, and patients had received as many as six prior cycles of therapy. Furthermore, most patients (89%) had intermediate or unfavorable cytogenetic risk status. The most common treatment-emergent non-hematologic adverse events of any grade were diarrhea, hypokalemia, nausea, and stomatitis. In the efficacy population, (all first relapsed or primary refractory patients treated with vosaroxin 80-90 mg/m²; n=69), the CR and combined CR rates (CR or CR with incomplete blood count recovery) were 25% and 28%, respectively. Thirty-day all-cause mortality was 2.5% among all patients treated at 80-90 mg/m².

Phase 2 Single-Agent. The results from our completed Response Evaluation of Vosaroxin in Elderly AmL (REVEAL-1) trial, a Phase 2 trial of single agent vosaroxin in previously untreated, poor-risk elderly AML patients who are unlikely to benefit from standard induction chemotherapy, were published in the November 17, 2014 Online Version of Record of the British Journal of Haematology. The article, titled "REVEAL-1, a phase 2 dose regimen optimization study of vosaroxin in older poor-risk patients with previously untreated acute myeloid leukemia," is available online at: http://onlinelibrary.wiley.com/doi/10.1111/bjh.13214/abstract.

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The REVEAL-1 trial evaluated single-agent vosaroxin in patients ≥60 years of age (n=113) with previously untreated unfavorable prognosis AML. Dose regimen optimization was explored in sequential cohorts (A: 72 mg/m² on days 1, 8, 15; B: 72 mg/m² on days 1, 8; C: 72 mg/m² or 90 mg/m² on days 1, 4). The primary efficacy endpoint was combined complete remission rate (CR plus CR with incomplete platelet recovery, or CRp). The median age in the study was 75 years and most patients (82%) had 2 or more risk factors (age ≥ 70, antecedent hematologic disease, ECOG PS=2, or intermediate/unfavorable cytogenetics).

Common (>20%) grade ≥3 adverse events were thrombocytopenia, febrile neutropenia, anemia, neutropenia, sepsis, pneumonia, stomatitis, and hypokalemia. Overall CR and CR/CRp rates were 29% and 32%; median overall survival, or OS, was 7.0 months; 1-year OS was 34%. Schedule C (72 mg/m²) had the most favorable balance of safety and efficacy, with faster hematologic recovery (median 27 days) and lowest incidence of aggregate sepsis (24%) and 30-day (7%) and 60-day (17%) all-cause mortality. At this dose and schedule, CR and CR/CRp rates were 31% and 35%, median OS was 7.7 months, and 1-year OS was 38%.

Phase 1 Single-Agent. Prior to 2009, we conducted a Phase 1 clinical trial to evaluate safety, pharmacokinetics, and preliminary clinical activity of two dose schedules of vosaroxin in patients with relapsed or refractory acute leukemia. Anti-leukemic activity was observed in both schedules, and the most common dose-limiting toxicity was stomatitis. The maximum tolerated dose was 72 mg/m² for a once weekly for three weeks schedule and 40 mg/m² for a twice weekly for two weeks schedule.

Vosaroxin Company-Sponsored Clinical Trials in Ovarian Cancer and Other Solid Tumors

In 2010, we completed a Phase 2 single-agent trial of vosaroxin in platinum-resistant ovarian cancer. Three dosing levels in two treatment schedules were studied, and encouraging, durable anti-tumor activity was observed across all doses. For patients on dosing levels of 48, 60 and 75 mg/m², the overall response rate, or ORR, was 11%, 11% and 9%, respectively; disease control, defined as stable disease for 12 weeks or more, was 46%, 46% and 51%, respectively; and the median progression-free survival, or PFS, was 83, 61 and 103 days, respectively. Based on clinical activity and tolerability, the 60 mg/m² dose and schedule was selected for future consideration. Overall, vosaroxin was generally well tolerated, with more than 10% of patients experiencing severe neutropenia, febrile neutropenia, fatigue, and anemia.

Prior to 2009, we conducted two Phase 1 clinical trials to evaluate different dosing schedules of vosaroxin in patients with advanced solid tumors. We also conducted two Phase 2 trials in non-small cell lung cancer and small cell lung cancer. Although objective responses were observed in both lung cancer trials, it was determined that vosaroxin could be administered with greater dose intensity given the low incidence of severe neutropenia and the trials were halted.

Vosaroxin Investigator Sponsored Clinical Trials

MD Anderson. In July 2013, we announced the initiation of an investigator-sponsored trial of vosaroxin in combination with decitabine in older patients with previously untreated AML and high-risk MDS. The Phase 1/2 trial is being conducted at the University of Texas MD Anderson Cancer Center under the direction of Naval Daver, M.D., Assistant Professor, and Farhad Ravandi, M.D., Professor of Medicine and a principal investigator in the VALOR trial. The primary endpoints of the Phase 1 cohort of the study are to determine the safety, maximum tolerated dose, or MTD, and dose limiting toxicity, or DLT, of vosaroxin in combination with decitabine in patients with high-risk MDS or AML who are elderly and/or unable or unwilling to receive standard cytarabine plus anthracycline based chemotherapy. The primary endpoint of the Phase 2 cohort of the study is to determine the efficacy of the combination based on achievement of CR, and CR with incomplete blood count recovery, or CRi. Secondary endpoints include safety, CR duration, leukemia-free survival, and overall survival. In October 2013, we announced the commencement of the Phase 2 portion of the study. In December 2014, updated results from this study were presented at the ASH Annual Meeting. This trial is expected to enroll up to a combined total of approximately 70 patients.

Weill Cornell. In October 2013, we announced the initiation of a second investigator-sponsored trial of vosaroxin in adult patients with previously treated intermediate-2 or high-risk MDS. The trial is being conducted at Weill Cornell Medical College and New York-Presbyterian Hospital under the direction of Gail J. Roboz, M.D., Associate Professor of Medicine and Director of the Leukemia Program. The Phase 1/2, open-label, dose escalating trial is expected to enroll up to 40 patients with MDS who have previously failed treatment with hypomethylating agent-based therapy. Patient cohorts will initially receive escalating doses of vosaroxin over each 28 day treatment cycle. Once the MTD is determined, an expanded evaluation of safety and hematologic response or improvement rate at this dose level will be conducted in additional subjects, so that the total number of subjects exposed to this dose level increases to up to 15 subjects. In addition to MTD and DLT, study endpoints include the rate of complete remission, partial remission, hematologic improvement and blood transfusion requirements.

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Washington University. In December 2013, we announced the initiation of a third investigator-sponsored trial of vosaroxin in combination with azacitidine in patients with MDS. The trial is being conducted at the Washington University School of Medicine under the direction of Meagan A. Jacoby, M.D., Ph.D., Instructor of Medicine, Division of Oncology. The Phase 1/2, open label, dose-escalation trial will enroll up to approximately 40 patients with MDS who may have received up to three prior cycles of hypomethylating agent-based therapy. Patients will receive vosaroxin (days one and four) and azacitidine (days one through seven) for a maximum of six cycles. This dose escalation study is designed to enroll six patients per cohort in order to determine the MTD and DLT of the combination. Other endpoints include best response, safety, tolerability, and event-free, progression-free, disease-free and overall survival. Once the MTD is determined, up to an additional 20 patients will be enrolled, treated and evaluated at that dose level.

Cardiff University School of Medicine. In December 2011, we announced our participation in the randomized Phase 2/3 Less Intensive 1 (LI-1) Study being conducted by the United Kingdom's National Cancer Research Institute (NCRI) Haematological Oncology Study Group under the direction of Professor Alan K. Burnett, Head of Haematology, Department of Medical Genetics, Haematology & Pathology at Cardiff University School of Medicine.  The trial enrolled patients over the age of 60 with AML or high-risk MDS and randomized them to one of a number of treatment regimens: Low Dose Ara-C (control); single-agent vosaroxin; vosaroxin combined with Low Dose Ara-C; or to other experimental therapies considered for inclusion in the comparison.  In 2013, at the first interim analyses, the Data Monitoring and Ethics Committee recommended closure of the vosaroxin-containing trial arms as a clinically relevant benefit was unlikely.

MLN 2480

Background. A pan-Raf inhibitor program was originally developed through a collaboration agreement between Sunesis and Biogen Idec. In March 2011, Biogen Idec’s rights to this program were purchased by and exclusively licensed to Millennium. In September 2011, Millennium initiated a Phase 1 clinical study of MLN2480, an oral, investigative drug selective for pan-Raf kinase inhibition, in patients with relapsed or refractory solid tumors. The Phase 1, multicenter, open-label, dose escalation study was designed to evaluate the safety, tolerability and MTD of MLN2480, and to be conducted in two stages: dose escalation and cohort expansion. The dose escalation stage is complete and MTD was established, and MLN2480 is now in the cohort expansion stage of this multicenter study. Four abstracts of preclinical and clinical data of MLN2480 were presented at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics in November 2014.

Under the license agreement, we may in the future receive up to $57.5 million in pre-commercialization, event-based payments related to the development by Millennium of the first two indications for each of the licensed products directed against the Raf target, and royalty payments depending on related product sales, as further described below.

Mechanism of Action. The Raf kinases (A-Raf, B-Raf and C-Raf) are key regulators of cell proliferation and survival within the mitogen-activated protein kinase (MAPK) pathway.

Development Opportunity. MLN2480 is a pan-Raf kinase inhibitor with a distinct molecular signature which has exhibited a promising profile.

SNS-062

Background. SNS-062 is a non-covalently binding inhibitor of BTK. BTK mediates signaling through the B-cell receptor, or BCR, which is critical for adhesion, migration, proliferation and survival of normal and malignant B-lineage lymphoid cells. BTK has been well validated as a target for treatment of B-cell malignancies, with a BTK inhibitor approved for relapsed/refractory mantle cell lymphoma, relapsed/refractory chronic lymphocytic leukemia, or CLL, CLL with 17p depletion and Waldenström’s macroglobulinemia. We are currently conducting IND-enabling studies for SNS-062, with a view to filing an IND application with the FDA. The rights to develop SNS-062 for oncology indications were in-licensed from Biogen Idec in December 2013, as described below.

Mechanism of Action. SNS-062 has activity in BTK kinase assays and has shown efficacy in B-cell signaling assays and in vivo models of B-cell function. The mechanism by which SNS-062 inhibits BTK is distinct from the mechanism of in-class BTK compounds, as SNS-062 binds BTK non-covalently, which does not require interaction with Cysteine 481 in the kinase active domain. In addition, SNS-062 has a distinct kinase inhibitory profile and a favorable pharmacokinetic profile compared to covalently binding BTK inhibitors and this may translate into a distinct clinical benefit for patients.

Development Opportunity. SNS-062 has demonstrated a distinct binding site and favorable pharmacokinetic profile in preclinical studies, and may provide differentiated opportunities for treatment of B-cell malignancies and other blood cancers.  

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SNS-229 and SNS-510

Background. In January 2014, we in-licensed a series of selective PDK1 inhibitors from Millennium that were discovered under a research collaboration agreement between Biogen Idec and Sunesis, as described below. PDK1 is a key kinase and mediator of PI3K/AKT signaling, a pathway involved in cell growth, differentiation, survival and migration. PDK1 inhibitors are expected to have unique effects on survival and invasion signaling and to be broadly active in both hematologic and solid tumor malignancies. We have taken a series of PDK1 inhibitors with confirmed antitumor activity in vitro and in vivo into preclinical development, and in 2014, we selected two PDK1 inhibitors, SNS-229 and SNS-510, of which we plan to take at least one into IND-enabling ADME and safety studies in 2015.

Mechanism of Action. There are multiple PI3K pathway inhibitors in late stage development for use in CLL and solid tumor indications, including breast cancer and pancreatic cancer. Because PDK1-dependent activation of AKT is critical for PI3K pathway activation, we believe that PDK1 represents a key oncology target within the PI3K pathway. We believe Sunesis’ PDK1 inhibitors are potential first-in-class compounds with demonstrated inhibition of AKT activity and a compelling in vitro and in vivo profile, that have potential for single agent and broad-spectrum combination activity, thus providing a novel therapeutic opportunity for targeting the PI3K signaling pathway in both solid and hematologic malignancies.

Development Opportunity. Inhibitors of PDK1 are expected to be able to provide similar clinical benefits to those observed with PI3K inhibitors and have the potential to provide additional benefits through inhibition of PI3K independent cancer signaling pathways, especially in cancer types in which PDK1 is overexpressed such as breast cancer and AML. We believe that Sunesis’ PDK1 inhibitors can be differentiated from PI3K and PDK1 inhibitors currently in research and development and that may provide novel opportunities for treatment of solid and hematological malignancies.

License, Collaboration and Royalty Agreements

Inlicense Agreement with Sumitomo

In October 2003, we entered into an agreement with Sumitomo to acquire exclusive worldwide development and marketing rights for vosaroxin. In January 2011, we made a $0.5 million milestone payment to Sumitomo as a result of the initiation of our VALOR trial in December 2010. In the future we may be required to make additional milestone payments of up to $7.0 million in aggregate to Sumitomo for (a) filing NDAs, in the U.S., Europe and Japan, and (b) for receiving regulatory approvals in these regions, for cancer-related indications. If vosaroxin is approved for a non-cancer indication, an additional milestone payment will become payable to Sumitomo.

The agreement also provides for royalty payments to Sumitomo at rates based on total annual net sales. Under the agreement, we may reduce our royalty payments to Sumitomo if a third party markets a competitive product and we must pay royalties for third-party intellectual property rights necessary to commercialize vosaroxin. Royalty obligations under the agreement continue on a country-by-country and product-by-product basis until the later of the date on which no valid patent claims relating to a product exist or 10 years from the date of the first sale of the product.

If we discontinue seeking regulatory approval and/or the sale of the product in a region, we are required to return its rights to the product in that region to Sumitomo. The agreement may be terminated by either party for the other party’s uncured breach or bankruptcy.

Licensing and Collaboration Agreements with Biogen Idec and Millennium

Overview

In August 2004, we entered into the original collaboration agreement with Biogen Idec to discover, develop and commercialize small molecule inhibitors of the human protein Raf kinase, including family members Raf-1, A-Raf, B-Raf and C-Raf, collectively Raf, and up to five additional targets that play a role in oncology and immunology indications such as BTK and PDK1, or the Biogen Idec OCA.

In June 2008, the parties agreed to terminate the research term and related funding as of June 30, 2008. A total of $20.0 million of research funding was received through that date. We received a total of $3.0 million in milestone payments for meeting certain preclinical milestones through the Biogen Idec 1st ARCA date, as described below, including a $1.5 million event-based payment received in cash in July 2009 for Biogen Idec’s selection of a Raf kinase inhibitor development candidate for the treatment of cancer.

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In March 2011, as part of a series of agreements among Sunesis, Biogen Idec and Millennium, we entered into: (a) an amended and restated collaboration agreement with Biogen Idec, or the Biogen Idec 1st ARCA; (b) a license agreement with Millennium, or the Millennium Agreement; and (c) a termination and transition agreement among the Sunesis, Biogen Idec and Millennium, or the Termination and Transition Agreement.

The Termination and Transition Agreement provided for (a) the termination of Biogen Idec’s exclusive rights under the Biogen Idec OCA to all discovery programs under such agreement other than for small molecule inhibitors of the human protein BTK; (b) the permitted assignment to Millennium of all related Sunesis collaboration assets and rights to Raf kinase and the human protein PDK1; and (c) the payment of $4.0 million to us from Millennium, which was recorded as revenue in March 2011.

Biogen Idec

The Biogen Idec 1st ARCA amended and restated the Biogen Idec OCA, to provide for the discovery, development and commercialization of small molecule BTK inhibitors. Under this agreement, we no longer have research obligations, but licenses granted to Biogen Idec with respect to the research collaboration under the Biogen Idec OCA (other than the licenses transferred to Millennium under the Millennium Agreement) remain in effect.

In June 2012, we received an event-based payment of $1.5 million from Biogen Idec for its advancement of pre-clinical work in connection with the Biogen Idec 1st ARCA. Under this agreement, we are eligible to receive up to an additional $58.5 million in pre-commercialization, event-based payments related to the development by Biogen Idec of the first two indications for licensed products against the BTK target. We are also eligible to receive royalty payments depending on related product sales, which may be increased if we exercise our option to co-fund product candidates worldwide.

In December 2013, we entered into a second amended and restated collaboration agreement with Biogen Idec, or the Biogen Idec 2nd ARCA, which amended and restated the Biogen Idec 1st ARCA, to provide us with an exclusive worldwide license to develop, manufacture and commercialize SNS-062, a BTK inhibitor synthesized under the Biogen Idec 1st ARCA, solely for oncology indications. Under the Biogen Idec 2nd ARCA, we may be required to make a $2.5 million milestone payment depending on our development of SNS-062 and royalty payments depending on related product sales of SNS-062. Additionally, potential future royalty payments to Sunesis were reduced to equal those amounts due to Biogen Idec for potential future sales of SNS-062. All other of Sunesis’ rights contained in the Biogen Idec 1st ARCA remain unchanged.

Millennium

Under the Millennium Agreement, we granted exclusive licenses to products against two oncology targets originally developed under the Biogen Idec OCA, Raf and PDK1, under substantially the same terms as under the Biogen Idec OCA.

In January 2014, we entered into an amended and restated license agreement with Millennium, or the Amended Millennium Agreement, to provide us with an exclusive worldwide license to develop and commercialize preclinical inhibitors of PDK1. In connection with execution of the Amended Millennium Agreement, we paid an upfront fee and may in the future be required to make up to $9.2 million in pre-commercialization milestone payments depending on our development of PDK1 inhibitors and royalty payments depending on related product sales.

With respect to the Raf target product rights that were originally licensed to Millennium under the Millennium Agreement, we may in the future receive up to $57.5 million in pre-commercialization, event-based payments related to the development by Millennium of the first two indications for each of the licensed products directed against the Raf target and royalty payments depending on related product sales. The agreement also provides us with future co-development and co-promotion rights. Millennium is currently conducting a Phase 1 clinical study of an oral investigative drug, MLN2480, which is licensed to them under the Amended Millennium Agreement.

Royalty Agreement with RPI

In March 2012, we entered into a Revenue Participation Agreement, or the Royalty Agreement, with RPI Finance Trust, or RPI, an entity related to Royalty Pharma. In September 2012, as a result of the recommendation by the DSMB to increase the sample size for the VALOR trial, RPI made a $25.0 million cash payment to us in exchange for a 6.75% royalty on any future net sales of vosaroxin. In conjunction with the Royalty Agreement, we issued two five-year warrants to RPI, each to purchase 1,000,000 shares of our common stock, at exercise prices of $3.48 and $4.64 per share, respectively. Of the $25.0 million, $21.9 million was recorded as deferred revenue and is being amortized to revenue over the related performance period of the Royalty Agreement. The remaining $3.1 million represents the fair value of the warrants. Both warrants were exercised in full in 2014.

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Revenues

Over the past three years, we have generated revenue through the Royalty Agreement with RPI and the Biogen Idec 1st ARCA. In 2014 and 2013, we recognized $5.7 million and $8.0 million of revenue, respectively, related to the Royalty Agreement with RPI. In 2012, we recognized $2.3 million of revenue related to the Royalty Agreement with RPI and $1.5 million related to the Biogen Idec 1st ARCA, which represented 60% and 40% of 2012 revenues, respectively.

Manufacturing

We do not have internal manufacturing capabilities for the production of clinical or commercial quantities of vosaroxin. To date, we have relied on, and we expect to continue to rely on, a limited number of third-party contract manufacturers for the production of clinical and commercial quantities of the vosaroxin active pharmaceutical ingredient, or API, and the finished drug product incorporating the API, or FDP. We do not have commercial supply agreements with any of these third parties, and our agreements with these parties may include provisions that allow for termination at will by either party following a relatively short notice period.

We currently rely on two contract manufacturers for the vosaroxin API. We also currently rely on a single contract manufacturer to formulate the vosaroxin API and fill and finish vials of the vosaroxin FDP. Because the vosaroxin API is classified as a cytotoxic substance, the number of available manufacturers for the API and FDP is limited. We believe at least five contract manufacturers in North America have suitable facilities to manufacture the vosaroxin API, and at least four have suitable facilities to manufacture the vosaroxin FDP. A number of manufacturers outside of North America have suitable facilities, including one that currently manufactures our vosaroxin API. If we are unable to obtain sufficient quantities of the vosaroxin API and FDP from our current manufacturers, it may take time to engage alternative manufacturers, which could delay the development of and impair our ability to commercialize vosaroxin.

To date, vosaroxin has been manufactured in quantities appropriate for preclinical studies and clinical trials, including the manufacture of registration batches of API and FDP. Prior to commercial sale, we will need to perform process validation studies on API and FDP batches. If the results of these process validation studies do not meet preset criteria, the regulatory approval or commercial launch of vosaroxin may be delayed.

Competition

The life sciences industry is highly competitive, and we face significant competition from many pharmaceutical, biopharmaceutical and biotechnology companies that are researching, developing and marketing products designed to address the treatment of cancer, including AML, MDS and B-cell malignancies. Many of our competitors have significantly greater financial, manufacturing, marketing and drug development resources than we do. Large pharmaceutical companies in particular have extensive experience in the clinical testing of, obtaining regulatory approvals for, and marketing drugs.

We believe that our ability to successfully compete in the marketplace with vosaroxin and any future product candidates will depend on, among other things:

· our ability to develop novel compounds with attractive pharmaceutical properties and to secure, protect and maintain intellectual property rights based on our innovations;

· the efficacy, safety and reliability of our product candidates;

· the speed at which we develop our product candidates;

· our ability to design and successfully execute appropriate clinical trials;

· our ability to maintain a good relationship with regulatory authorities;

· our ability to obtain, and the timing and scope of, regulatory approvals;

· our ability to manufacture and sell commercial quantities of future products to the market;

· the availability of reimbursement from government agencies and private insurance companies; and

· acceptance of future products by physicians and other healthcare providers.

Vosaroxin is a small molecule therapeutic that, if approved, will compete with other drugs and therapies currently used for AML, such as nucleoside analogs, anthracyclines, hypomethylating agents, other inhibitors of topoisomerase II, and other novel agents. Additionally, other compounds currently in development could become potential competitors of vosaroxin, if approved for marketing. We expect competition with vosaroxin for the treatment of AML and other potential future indications to increase as additional products are developed and approved for use in various patient populations.

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Intellectual Property

We believe that patent protection is very important to our business and that our future success depends in part on our ability to obtain patents protecting vosaroxin or future drug candidates, if any. Historically, we have patented a wide range of technology, inventions and improvements related to our business, some of which we are no longer actively developing.

The vosaroxin composition-of-matter is covered by U.S. Patent No. 5,817,669 and its counterpart patents in 43 foreign jurisdictions. This U.S. patent is due to expire in October 2015, and most of its foreign counterparts are due to expire in June 2015. While it is possible that patent term restoration and/or supplemental patent certificates would be available for some of these or other patents we own or control through licenses, we cannot guarantee that such additional protection will be obtained, and the expiration dates described here do not include such term restoration.

We have been granted additional patents relating to vosaroxin compositions, and uses and manufacture of vosaroxin, in the U.S.:

· U.S. Patent No. 7,989,468 claims methods of use of vosaroxin at clinically relevant dose ranges and schedules for the treatment of leukemia, with expiry in 2026;

· U.S. Patent Nos. 7,829,577 and 8,669,270 claim certain pharmaceutical compositions of vosaroxin, including the formulation used in our VALOR trial, with expiry in 2025;

· U.S. Patent No. 8,580,814 claims certain methods of use of vosaroxin at clinically relevant dose ranges to treat acute myelogenous leukemia, with expiry in 2026;

· U.S. Patent No. 8,822,493 claims certain methods of use of vosaroxin at clinically relevant dose ranges together with therapeutically effective amounts of cytarabine to treat cancer, with expiry in 2024;

· U.S. 8,124,773 B2 claims a hydrate of vosaroxin with expiry in 2028 and U.S. Patent No. 8,765,954 claims certain compositions containing this hydrate of vosaroxin, with expiry in 2027;

· U.S. Patent No. 8,497,282 claims a method of making vosaroxin, with expiry in 2031 and U.S. Patent No. 8,802,719 claims certain intermediates useful in the making of vosaroxin, with expiry in 2029;

· U.S. Patent Nos. 8,586,601 and 8,138,202 claim certain compositions containing vosaroxin, with expiry in 2030; and

· U.S. Patent No. 7,968,565 claims a combination of vosaroxin and cytarabine, with expiry in 2026.

We have been granted additional patents relating to vosaroxin compositions, and uses and manufacture of vosaroxin, in Europe:

· EPO Patent No. 1725233 B1, which has been validated in multiple European Patent Office, or EPO, member states, claims certain pharmaceutical compositions of vosaroxin, including the formulation used in our VALOR trial, with expiry in 2025; and

· EP Patent No. 1729770 B1, which has been validated in multiple EPO member states, claims combinations of vosaroxin and certain anticancer agents, including cytarabine, with expiry in 2025.

In addition to the listed US and European patents, we have been granted similar and related patents in certain other countries, and patent applications are pending in these and other countries, including major markets, throughout the world. Other patents have also been granted in the US and other countries claiming certain technology related to vosaroxin and other methods of use of vosaroxin.

As of December 31, 2014, we own, co-own or have rights to approximately 171 granted U.S. and foreign patents, and approximately 136 pending U.S. and foreign applications, pertaining to vosaroxin and compositions and uses thereof. When appropriate, we intend to seek patent term restoration, orphan drug status and/or data exclusivity in the United States and their equivalents in other relevant jurisdictions, to the maximum extent that the respective laws will permit at such time. In April 2012, the European Commission granted orphan drug designation to vosaroxin for the treatment of AML, which may provide for 10 years of marketing exclusivity in all member countries of the European Union following product approval for this indication in Europe. In 2009, the FDA granted orphan drug designation to vosaroxin for the treatment of AML.

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Our ability to build and maintain our proprietary position for vosaroxin and any future drug candidates, if any, will depend on our success in obtaining effective claims and enforcing granted claims. The patent positions of biopharmaceutical companies like ours are generally uncertain and involve complex legal and factual questions for which some important legal principles remain unresolved. No consistent policy regarding the breadth of patent claims has emerged to date in the United States. The patent situation outside the United States is even more uncertain. We do not know whether any of our patent applications or those patent applications that we license will result in the issuance of any patents. Even if patents are issued, they may not be sufficient to protect vosaroxin or future drug candidates, if any. The patents we own or license and those that may be issued in the future may be opposed, challenged, invalidated or circumvented, and the rights granted under any issued patents may not provide us with proprietary protection or competitive advantages.

Patent applications filed before November 29, 2000 in the United States are maintained in secrecy until patents issue. Later-filed U.S. applications and patent applications in most foreign countries generally are not published until at least 18 months after their earliest filing date. Scientific and patent publication often occurs long after the date of the scientific discoveries disclosed in those publications. Accordingly, we cannot be certain that we were the first to invent the subject matter covered by any patent application or that we were the first to file a patent application for any inventions.

Our commercial success depends on our ability to operate without infringing patents and proprietary rights of third parties. We cannot determine with certainty whether patents or patent applications of other parties may materially affect our ability to conduct our business. The existence of third party patent applications and patents could significantly reduce the coverage of patents owned by or licensed to us and limit our ability to obtain meaningful patent protection. If patents containing competitive or conflicting claims are issued to third parties and these claims are ultimately determined to be valid, we may be enjoined from pursuing research, development or commercialization of vosaroxin or future drug candidates, if any, or be required to obtain licenses to such patents or to develop or obtain alternative technology.

We may need to commence or defend litigation to enforce or to determine the scope and validity of any patents issued to us or to determine the scope and validity of third party proprietary rights. Litigation would result in substantial costs, even if the eventual outcome is favorable to us. An adverse outcome in litigation affecting proprietary rights we own or have licensed could present significant risk of competition for vosaroxin or future drug candidates, if any, that we market or seek to develop. Any adverse outcome in litigation affecting third party proprietary rights could subject us to significant liabilities to third parties and could require us to seek licenses of the disputed rights from third parties or to cease using the technology if such licenses are unavailable.

We also rely on trade secrets to protect our technology, especially in situations or jurisdictions in which we believe patent protection may not be appropriate or obtainable. However, trade secrets are difficult to maintain and do not protect technology against independent developments made by third parties.

We seek to protect our proprietary information by requiring our employees, consultants, contractors and other advisers to execute nondisclosure and assignment of invention agreements upon commencement of their employment or engagement. Agreements with our employees also prevent them from bringing the proprietary rights of third parties to us. We also require confidentiality or material transfer agreements from third parties that receive our confidential data or materials. There can be no assurance that these agreements will provide meaningful protection, that these agreements will not be breached, that we will have an adequate remedy for any such breach, or that our trade secrets will not otherwise become known or independently developed by a third party.

We seek to protect our company name and the names of our products and technologies by obtaining trademark registrations, as well as common law rights in trademarks and service marks, in the United States and in other countries. There can be no assurance that the trademarks or service marks we use or register will protect our company name or any products or technologies that we develop and commercialize, that our trademarks, service marks, or trademark registrations will be enforceable against third parties, or that our trademarks and service marks will not interfere with or infringe trademark rights of third parties. We may need to commence litigation to enforce our trademarks and service marks or to determine the scope and validity of our or a third party’s trademark rights. Litigation would result in substantial costs, even if the eventual outcome is favorable to us. An adverse outcome in litigation could subject us to significant liabilities to third parties and require us to seek licenses of the disputed rights from third parties or to cease using the trademarks or service marks if such licenses are unavailable.

Government Regulation

The FDA and comparable regulatory agencies in state and local jurisdictions and in foreign countries impose substantial requirements upon the clinical development, manufacture, marketing and distribution of drugs. These agencies and other federal, state and local entities regulate research and development activities and the testing, manufacture, quality control, safety, efficacy, labeling, storage, recordkeeping, approval, advertising and promotion of vosaroxin and any future drug candidates we may develop, if any. The application of these regulatory frameworks to the development, approval and commercialization of vosaroxin or our future drug candidates, if any, will take a number of years to accomplish, if at all, and involve the expenditure of substantial resources.

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In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, as amended, and implementing regulations. The process required by the FDA before vosaroxin and any future drug candidates may be marketed in the United States generally involves the following:

· completion of extensive preclinical laboratory tests, in vivo preclinical studies and formulation studies;

· submission to the FDA of an IND application, which must become effective before clinical trials begin;

· performance of adequate and well-controlled clinical trials to establish the safety and efficacy of the product candidate for each proposed indication;

· submission of an NDA to the FDA;

· satisfactory completion of an FDA pre-approval inspection of the manufacturing facilities at which the product candidate is produced to assess compliance with current Good Manufacturing Practice, or cGMP, regulations; and

· FDA review and approval of the NDA, including proposed labeling (package insert information) and promotional materials, prior to any commercial marketing, sale or shipment of the drug.

The testing and approval process requires substantial time, effort and financial resources, and we cannot be certain that any approvals for vosaroxin or our future drug candidates, if any, will be granted on a timely basis, if at all.

Preclinical Testing and INDs

Preclinical tests include laboratory evaluation of product chemistry, formulation and stability, as well as studies to evaluate toxicity in animals. Laboratories that comply with the FDA Good Laboratory Practice regulations must conduct preclinical safety tests. The results of preclinical tests, together with manufacturing information and analytical data, are submitted as part of an IND application to the FDA. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, raises concerns or questions about the conduct of the clinical trial, including concerns that human research subjects will be exposed to unreasonable health risks. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. Our submission of an IND, or those submitted by Biogen Idec, Millennium, or our potential future licensees or collaboration partners, if any, may not result in FDA authorization to commence a clinical trial.

Clinical Trials

Clinical trials involve the administration of an investigational drug to healthy volunteers or to patients under the supervision of a qualified principal investigator. Clinical trials are conducted in accordance with the FDA’s Protection of Human Subjects regulations and Good Clinical Practices, or GCP, under protocols that detail the objectives of the study, the parameters to be used to monitor safety, and the efficacy criteria to be evaluated. Each protocol must be submitted to the FDA as part of the IND application.

In addition, each clinical study must be conducted under the auspices of an independent institutional review board, or IRB, at each institution where the study will be conducted. Each IRB will consider, among other things, ethical factors, the safety of human subjects and the possible liability of the institution. The FDA, an IRB or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the subjects or patients are being exposed to an unacceptable health risk. Clinical testing also must satisfy extensive GCP requirements and regulations for informed consent.

Clinical trials are typically conducted in three sequential phases, which may overlap, sometimes followed by a fourth phase:

· Phase 1 clinical trials are initially conducted in a limited population to test the drug candidate for safety (adverse effects), dose tolerance, absorption, metabolism, distribution and excretion in healthy humans or, on occasion, in patients, such as cancer patients. In some cases, particularly in cancer trials, a sponsor may decide to conduct what is referred to as a “Phase 1b” evaluation, which is a second safety-focused Phase 1 clinical trial typically designed to evaluate the impact of the drug candidate in combination with currently approved drugs.

· Phase 2 clinical trials are generally conducted in a limited patient population to identify possible adverse effects and safety risks, to determine the efficacy of the drug candidate for specific targeted indications and to determine dose tolerance and optimal dosage. Multiple Phase 2 clinical trials may be conducted by the sponsor to obtain information prior to beginning larger and more expensive Phase 3 clinical trials. In some cases, a sponsor may decide to conduct what is referred to as a “Phase 2b” evaluation, which is a second, confirmatory Phase 2 clinical trial that could, if positive and accepted by the FDA, serve as a pivotal clinical trial in the approval of a drug candidate.

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· Phase 3 clinical trials are commonly referred to as pivotal trials. When Phase 2 clinical trials demonstrate that a drug candidate has potential activity in a disease or condition and has an acceptable safety profile, Phase 3 clinical trials are undertaken to further evaluate clinical efficacy and to further test for safety in an expanded patient population at multiple, geographically dispersed clinical trial sites.

· Phase 4 (post-marketing) clinical trials may be required by the FDA in some cases. The FDA may conditionally approve an NDA for a drug candidate on a sponsor’s agreement to conduct additional clinical trials to further assess the drug’s safety and/or efficacy after NDA approval. Such post-approval trials are typically referred to as Phase 4 clinical trials.

New Drug Applications

Assuming successful completion of the required clinical testing, the results of the preclinical studies and clinical trials, together with detailed information relating to the product’s chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the product for one or more indications. Under federal law, the submission of most NDAs is additionally subject to a substantial application user fee under the Prescription Drug User Fee Act, or PDUFA, and the sponsor of an approved NDA is also subject to annual product and establishment user fees, which fees are typically increased annually.

The FDA conducts a preliminary review of all NDAs within the first 60 days after submission before accepting them for filing to determine whether they are sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA has agreed to specified performance goals in the review of NDAs. Under these goals, the FDA has committed to review most such applications for non-priority products within 10 months of filing, and most applications for priority review products, that is, drugs that the FDA determines represent a significant improvement over existing therapy, within six months of filing. The review process may be extended by the FDA for three additional months to consider certain information or clarification regarding information already provided in the submission. The FDA may also refer applications for novel drugs or products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. In addition, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP and integrity of the clinical data submitted.

The testing and approval process requires substantial time, effort and financial resources, and each may take many years to complete. Data obtained from clinical activities are not always conclusive and may be susceptible to varying interpretations, which could delay, limit or prevent regulatory approval. The FDA may not grant approval on a timely basis, or at all. We may encounter difficulties or unanticipated costs in our efforts to develop our product candidates and secure necessary governmental approvals, which could delay or preclude us from marketing our products.

After the FDA’s evaluation of the NDA and inspection of the manufacturing facilities, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the NDA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval and refuse to approve the NDA. Even if the FDA approves a product, it may limit the approved indications for use for the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess a drug’s safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including Risk Evaluation and Mitigation Strategies, or REMs, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.

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Orphan Drug Designation

The United States Orphan Drug Act promotes the development of products that demonstrate promise for the diagnosis and treatment of diseases or conditions that affect fewer than 200,000 people in the United States. Upon receipt of orphan drug designation from the FDA, the sponsor is eligible for tax credits of up to 50% for qualified clinical trial expenses, the ability to apply for annual grant funding, waiver of PDUFA application fee, and upon approval, the potential for seven years of market exclusivity for the orphan-designated product for the orphan-designated indication. In October 2009, the FDA granted orphan drug designation to vosaroxin for treatment of AML.

In the European Union, orphan status is available for therapies addressing conditions that affect five or fewer out of 10,000 people, and provides for the potential for 10 years of marketing exclusivity in Europe for the orphan-designated product for the orphan-designated indication. The marketing exclusivity period can be reduced to six years if, at the end of the fifth year, available evidence establishes that the product is sufficiently profitable not to justify maintenance of market exclusivity. In April 2012, the European Commission granted orphan drug designation to vosaroxin for the treatment of AML.

Fast Track Designation

The FDA’s fast track program is intended to facilitate the development, and to expedite the review, of drugs that are intended for the treatment of a serious or life-threatening condition for which there is no effective treatment and demonstrate the potential to address unmet medical needs for the condition.

With fast track designation, the FDA may initiate review of sections of an NDA before the application is complete. This rolling review is available if the applicant provides and the FDA approves a schedule for the submission of the remaining information and the applicant pays applicable user fees. However, the time period specified in the PDUFA, which governs the time period goals the FDA has committed to reviewing an application, does not begin until the complete application is submitted. Additionally, the fast track designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

In some cases, a fast track designated drug candidate may also qualify for priority review. Under FDA policies, a drug candidate is eligible for priority review, or, under Prescription Drug User Fee Act V, review within eight months from the time a complete NDA is submitted (a six-month review period begins at the conclusion of the 60-day filing review period that begins on the date of FDA receipt of the submission), if the drug candidate provides a significant improvement compared to marketed drugs in the treatment, diagnosis or prevention of a disease. A fast track designated drug candidate would ordinarily meet the FDA’s criteria for priority review.

In February 2011, the FDA granted fast track designation to vosaroxin for the potential treatment of relapsed or refractory AML in combination with cytarabine. We do not know whether vosaroxin or our future drug candidates, if any, will receive a priority review designation or, if a priority designation is received, whether that review or approval will be faster than conventional FDA procedures, or the ultimate impact, if any, of the fast track designation on the timing or likelihood of FDA approval of vosaroxin or our future drug candidates, if any.

Satisfaction of FDA regulations and approval requirements or similar requirements of foreign regulatory agencies typically takes several years, and the actual time required may vary substantially based upon the type, complexity and novelty of the product or disease. Typically, if a drug candidate is intended to treat a chronic disease, as is the case with vosaroxin, safety and efficacy data must be gathered over an extended period of time. Government regulation may delay or prevent marketing of drug candidates for a considerable period of time and impose costly procedures upon our activities. The FDA or any other regulatory agency may not grant approvals for new indications for our drug candidates on a timely basis, or at all. Even if a drug candidate receives regulatory approval, the approval may be significantly limited to specific disease states, patient populations and dosages. Further, even after regulatory approval is obtained, later discovery of previously unknown problems with a drug may result in restrictions on the drug or even complete withdrawal of the drug from the market. Delays in obtaining, or failures to obtain, regulatory approvals for any of our drug candidates would harm our business. In addition, we cannot predict what adverse governmental regulations may arise from future U.S. or foreign governmental action.

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Other Regulatory Requirements

Any drugs manufactured or distributed by us, Biogen Idec, Millennium, or our potential future licensees or collaboration partners, if any, pursuant to FDA approvals are subject to continuing regulation by the FDA, including recordkeeping requirements and reporting of adverse experiences associated with the drug. Drug manufacturers and their subcontractors are required to register with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with ongoing regulatory requirements, including cGMPs, which impose certain procedural and documentation requirements upon us and our third-party manufacturers. Failure to comply with the statutory and regulatory requirements can subject a manufacturer to possible legal or regulatory action, such as warning letters, suspension of manufacturing, seizure of product, injunctive action or possible civil penalties.

The FDA closely regulates the post-approval marketing and promotion of drugs, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the Internet. A company can make only those claims relating to safety and efficacy that are approved by the FDA. Failure to comply with these requirements can result in adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available drugs for uses that are not described in the drug’s labeling and that differ from those tested by us and approved by the FDA. Such off-label uses are common across medical specialties, including cancer therapy. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, impose stringent restrictions on manufacturers’ communications regarding off-label use.

Reimbursement

Sales of any of our product candidates, if approved, will depend, in part, on the extent to which the costs of the products will be covered by third-party payors, including government health programs such as Medicare and Medicaid, commercial health insurers and managed care organizations. These third-party payors have been increasingly challenging the prices charged for medical products and services. Additionally, the containment of healthcare costs has become a priority of federal and state governments, and the prices of drugs have been a focus in this effort. In particular, government entities have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit our ability to achieve significant net sales and results. If these third-party payors do not consider our products to be cost-effective compared to other available therapies, they may not cover our products after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis.

Current and future legislative proposals to further reform healthcare or reduce healthcare costs may result in lower reimbursement for our products. The cost containment measures that payors and providers are instituting and the effect of any healthcare reform initiative implemented in the future could significantly reduce our revenues from the sale of our products.

For example, implementation of the Affordable Care Act has the potential to substantially change healthcare financing and delivery by both governmental and private insurers, and significantly impact the pharmaceutical industry.  The Affordable Care Act, among other things, established an annual, nondeductible fee on any entity that manufactures or imports certain specified branded prescription drugs and biologic agents, increased the minimum Medicaid rebates owed by most manufacturers under the Medicaid Drug Rebate Program, extended the Medicaid Drug Rebate program to utilization of prescriptions of individuals enrolled in Medicaid managed care organizations, and provided incentives to programs that increase the federal government’s comparative effectiveness research.  In addition, other legislative changes have been proposed and adopted since the Affordable Care Act was enacted. In August 2011, the President signed into law the Budget Control Act of 2011, which, among other things, created the Joint Select Committee on Deficit Reduction to recommend to Congress proposals in spending reductions. The Joint Select Committee did not achieve a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, triggering the legislation’s automatic reduction to several government programs. This includes reductions to Medicare payments to providers of 2% per fiscal year, which went into effect in April 2013 and will remain in effect through 2024 unless additional congressional action is taken. Additionally, in January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, reduced Medicare payments to several providers and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our products or additional pricing pressure.

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Healthcare Law and Regulation

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws restrict our business activities, including certain marketing practices. These laws include, without limitation, anti-kickback laws,false claims laws, data privacy and security laws, as well as transparency laws regarding payments or other items of value provided to healthcare providers.

The federal healthcare program anti-kickback statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item, good, facility or service reimbursable under Medicare, Medicaid or other federal healthcare programs. The term “remuneration” has been broadly interpreted to include anything of value. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers and formulary managers on the other. Although there are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution or other regulatory sanctions, the exceptions and safe harbors are drawn narrowly, and practices that involve remuneration that are alleged to be intended to induce prescribing, purchases or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor. Failure to meet all of the requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the federal healthcare program anti-kickback statute.  Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all its facts and circumstances. Several courts have interpreted the statute’s intent requirement to mean that if any one purpose of an arrangement involving remuneration is to induce referrals of federal healthcare covered business, the federal healthcare program anti-kickback statute has been violated. Additionally, the intent standard under the federal healthcare program anti-kickback statute was amended by the Patient Protection and Affordable Care Act of 2010, as amended by the Health Care and Education Reconciliation Act of 2010, collectively the Affordable Care Act, to a stricter standard such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the Affordable Care Act codified case law that a claim including items or services resulting from a violation of the federal healthcare program anti-kickback statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act.

Federal false claims laws, including the civil False Claims Act, and civil monetary penalties laws, prohibit any person or entity from, among other things, knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to have a false claim paid. Pharmaceutical and other healthcare companies have been prosecuted under these laws for, among other things, allegedly inflating drug prices they report to pricing services, which in turn were used by the government to set Medicare and Medicaid reimbursement rates, and for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. In addition, certain marketing practices, including off-label promotion, may also violate false claims laws.

The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created new federal criminal statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Like the federal healthcare program anti-kickback statute, the Affordable Care Act amended the intent standard for certain healthcare fraud under HIPAA such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

In addition, we may be subject to data privacy and security regulation by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its implementing regulations, imposes certain requirements relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s security standards directly applicable to business associates, independent contractors or agents of covered entities that receive or obtain protected health information in connection with providing a service on behalf of a covered entity. HITECH also created four new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions.

Additionally, the federal Physician Payments Sunshine Act, created under  the Affordable Care Act, and its implementing regulations, require certain manufacturers of drugs, devices, biologicals and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) to report information related to certain payments or other transfers of value provided to physicians and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians and their immediate family members.

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The majority of states also have statutes or regulations similar to the aforementioned federal laws, some of which are broader in scope and apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor.

If our operations are found to be in violation of any of the health regulatory laws described above or any other laws that apply to us, we may be subject to penalties, potentially significant criminal and civil and/or administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government healthcare programs, contractual damages, reputational harm, administrative burdens, diminished profits and future earnings, and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

Foreign Regulation

In addition to regulations in the United States, we are subject to foreign regulations governing clinical trials and commercial sales and distribution of vosaroxin or our future drug candidates, if any. Our VALOR trial enrolled patients in Europe, Canada, South Korea, Australia and New Zealand. We may in the future initiate clinical trials in other countries throughout the world. Whether or not we obtain FDA approval for a product, we must obtain approval of a product by the comparable regulatory authorities of foreign countries before we can commence clinical trials or marketing of the product in those countries. The approval process varies from country to country, and the time may be longer or shorter than that required for FDA approval. The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from country to country.

Under European Union regulatory systems, permission to conduct clinical research is granted by the Competent Authority of each European Member State, or MS, and the applicable Ethics Committees, or EC, through the submission of a Clinical Trial Application. An EC in the European Union serves the same function as an IRB in the United States. The review times vary by MS but may not exceed 60 days. The EC has a maximum of 60 days to give its opinion on the acceptability of the Clinical Trial Application to both the governing MS and the sponsor applicant. If the application is deemed acceptable, the MS informs the applicant (or does not within the 60-day window inform the applicant of non-acceptance) and the company may proceed with the clinical trial.

To obtain a marketing authorization of a drug in the European Union, we must submit a marketing authorization application, or MAA, under the centralized procedure for vosaroxin. The centralized procedure provides for the grant of a single marketing authorization from the European Commission following a favorable opinion by the Committee for Medicinal Products for Human Use, or the CHMP, of the EMA that is valid in all European Union member states, as well as Iceland, Liechtenstein and Norway. The centralized procedure is compulsory for medicines produced by specified biotechnological processes, products designated as orphan medicinal products, advanced therapy medicinal products and products with a new active substance indicated for the treatment of specified diseases. Under the centralized procedure the maximum timeframe for the evaluation of an MAA by the EMA is 210 days, excluding clock stops, when additional written or oral information is to be provided by the applicant in response to questions asked by the CHMP.

In the EEA, the EMA’s Committee for Orphan Medicinal Products grants orphan drug designation to promote the development of products that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting not more than five in 10,000 persons in the European Union and for which no satisfactory method of diagnosis, prevention, or treatment has been authorized (or the product would be a significant benefit to those affected). Additionally, designation is granted for products intended for the diagnosis, prevention, or treatment of a life-threatening, seriously debilitating or serious and chronic condition and when, without incentives, it is unlikely that sales of the drug in the European Union would be sufficient to justify the necessary investment in developing the medicinal product. A European Union orphan drug designation entitles a party to financial incentives such as reduction of fees or fee waivers and 10 years of market exclusivity is granted following medicinal product approval. This period may be reduced to six years if the orphan drug designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity. Orphan drug designation must be requested before submitting an application for marketing approval. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

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In the EEA, marketing authorization applications for new medicinal products not authorized have to include the results of studies conducted in the pediatric population, in compliance with a pediatric investigation plan, or PIP, agreed with the EMA’s Pediatric Committee, or the PDCO. The PIP sets out the timing and measures proposed to generate data to support a pediatric indication of the drug for which marketing authorization is being sought. The PDCO can grant a deferral of the obligation to implement some or all of the measures of the PIP until there are sufficient data to demonstrate the efficacy and safety of the product in adults. Further, the obligation to provide pediatric clinical trial data can be waived by the PDCO when these data is not needed or appropriate because the product is likely to be ineffective or unsafe in children, the disease or condition for which the product is intended occurs only in adult populations, or when the product does not represent a significant therapeutic benefit over existing treatments for pediatric patients. Once the marketing authorization is obtained in all Member States of the European Union and study results are included in the product information, even when negative, the product is eligible for six months’ supplementary protection certificate extension. For orphan-designated medicinal products, the 10-year period of market exclusivity is extended to 12 years.

Under the Canadian regulatory system, Health Canada is the regulatory body that governs the sale of drugs and their use in clinical trials. Accordingly, any company that wishes to conduct a clinical trial in Canada must submit a clinical trial application to Health Canada. Health Canada reviews the application and notifies the company within 30 days if the application is found to be deficient. If the application is deemed acceptable, Health Canada will issue a no objection letter to the company within the 30-day review period which means the company may proceed with its clinical trial(s).

In addition to regulations in the United States, the European Union and Canada, we will be subject to a variety of other foreign regulations governing clinical trials and commercial distribution of our product candidates. Our ability to sell drugs will also depend on the availability of reimbursement from government and private insurance companies.

Research and Development Expenses

We incurred $27.7 million, $28.9 million and $29.2 million of research and development expenses in 2014, 2013 and 2012, respectively, primarily related to the development of vosaroxin. We expect to continue to incur significant development expenses related to the development of vosaroxin.

Environment

We have made, and will continue to make, expenditures for environmental compliance and protection. We do not expect that such expenditures will have a material effect on our capital expenditures or results of operations in the foreseeable future.

Employees

As of December 31, 2014, our workforce consisted of 39 full-time equivalent employees, of which 20 are engaged in research and development and 19 are engaged in general and administrative, medical affairs and commercial planning functions. We have no collective bargaining agreements with our employees, and we have not experienced any work stoppages.

Corporate Background

We were incorporated in Delaware in February 1998. Our offices are headquartered at 395 Oyster Point Boulevard, Suite 400, South San Francisco, California 94080, and our telephone number is (650) 266-3500. Our website address is www.sunesis.com. Information contained in, or accessible through, our website is not incorporated by reference into and does not form a part of this report.

Available Information

Our website is located at www.sunesis.com. The contents of our website are not intended to be incorporated by reference into this Annual Report on Form 10-K or in any other report or document we file with the Securities and Exchange Commission, or SEC, and any references to our websites are intended to be inactive textual references only. The following filings are available through our website after we file them with the SEC: Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, as well as any amendments to such reports and all other filings pursuant to Section 13(a) or 15 (d) of the Securities Act. These filings are also available for download free of charge on our investor relations website. Additionally, copies of materials filed by us with the SEC may be accessed at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549 or at www.sec.gov. For information about the SEC’s Public Reference Room, contact 1-800-SEC-0330.

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ITEM 1A. RISK FACTORS

Investing in our common stock involves a high degree of risk. You should carefully consider the risks and uncertainties described below and all information contained in this Annual Report on Form 10-K in weighing a decision to purchase our common stock. If any of the possible adverse events described below actually occurs, we may be unable to conduct our business as currently planned and our financial condition and operating results could be adversely affected. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. In addition, the trading price of our common stock could decline due to the occurrence of any of these risks, and you may lose all or part of your investment. Please see “Special Note Regarding Forward-Looking Statements.”

Risks Related to Our Business

We need to raise substantial additional funding to pursue our regulatory strategy for the potential commercialization of QINPREZO^TM (vosaroxin), and to continue the development of vosaroxin and our other programs.

We believe that with $43.0 million in cash and investments held as of December 31, 2014, we currently have the resources to fund our operations through the first quarter of 2016.

However, we will need to raise substantial additional capital to:

· complete the development, regulatory strategy and potential commercialization of vosaroxin in AML;

· fund additional clinical trials of vosaroxin and seek regulatory approvals;

· expand our development activities;

· implement additional internal systems and infrastructure; and

· build or access commercialization and additional manufacturing capabilities and supplies.

Our future funding requirements and sources will depend on many factors, including but not limited to the:

· rate of progress and cost of our clinical trials;

· need for additional or expanded clinical trials;

· timing, economic and other terms of any licensing, collaboration or other similar arrangement into which we may enter;

· costs and timing of seeking and obtaining FDA, EMA, or other regulatory approvals;

· extent of our other development activities, including our other clinical programs and in-license agreements;

· costs associated with building or accessing commercialization and additional manufacturing capabilities and supplies;

· costs of acquiring or investing in businesses, product candidates and technologies, if any;

· costs of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights;

· effect of competing technological and market developments; and

· costs of supporting our arrangements with Biogen Idec, Millennium or any potential future licensees or partners.

Until we can generate a sufficient amount of licensing, collaboration or product revenue to finance our cash requirements, which we may never do, we expect to finance future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to vosaroxin or our other development programs, or a combination of the above. Any issuance of convertible debt securities, preferred stock or common stock may be at a discount from the then-current trading price of our common stock. If we issue additional common or preferred stock or securities convertible into common or preferred stock, our stockholders will experience additional dilution, which may be significant. Further, we do not know whether additional funding will be available on acceptable terms, or at all. If we are unable to raise substantial additional funding on acceptable terms, or at all, we will be forced to delay or reduce the scope of our vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease our operations.

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We have incurred losses since inception and anticipate that we will continue to incur losses for the foreseeable future. We may not ever achieve or sustain profitability.

We are not profitable and have incurred losses in each year since our inception in 1998. Our net losses for the years ended December 31, 2014, 2013 and 2012 were $43.0 million, $34.6 million and $44.0 million, respectively. As of December 31, 2014, we had an accumulated deficit of $522.7 million. We do not currently have any products that have been approved for marketing, and we continue to incur substantial development and general and administrative expenses related to our operations. We expect to continue to incur losses for the foreseeable future, and we expect these losses to increase significantly as we seek regulatory approvals for vosaroxin, and as we prepare to commercialize vosaroxin, if approved. Our losses, among other things, have caused and will continue to cause our stockholders’ equity and working capital to decrease.

To date, we have derived substantially all of our revenue from license and collaboration agreements. We currently have two agreements, the Biogen Idec 2nd ARCA and the Amended Millennium Agreement, which each include certain pre-commercialization event-based and royalty payments. We cannot predict whether we will receive any such payments under these agreements in the foreseeable future, or at all.

We also do not anticipate that we will generate revenue from the sale of products until at least 2016, if at all. In the absence of additional sources of capital, which may not be available to us on acceptable terms, or at all, the development of vosaroxin or future product candidates, if any, may be reduced in scope, delayed or terminated. If our product candidates or those of our collaborators fail in clinical trials or do not gain regulatory approval, or if our future products do not achieve market acceptance, we may never become profitable. Even if we achieve profitability in the future, we may not be able to sustain profitability in subsequent periods.

The development of vosaroxin could be halted or significantly delayed for various reasons; our clinical trials for vosaroxin may not lead to regulatory approval.

Vosaroxin is vulnerable to the risks of failure inherent in the drug development process. Our VALOR trial failed to meet its primary endpoint, and we may not be able to obtain regulatory approval for commercialization in any of the United States, Europe, or in other regions. We may need to conduct significant additional preclinical studies and clinical trials before we can attempt to demonstrate that vosaroxin is safe and effective to the satisfaction of the FDA and other regulatory authorities. Failure can occur at any stage of the development process, and successful preclinical studies and early clinical trials do not ensure that later clinical trials will be successful. A number of companies in the pharmaceutical industry have suffered significant setbacks in advanced clinical trials, even after obtaining promising results in earlier trials.

For example, we terminated two Phase 2 clinical trials of vosaroxin in small cell and non-small cell lung cancer, and the LI-1 trial, conducted by a co-operative group in Europe, was halted at an interim data analysis. If our clinical trials result in unacceptable toxicity or lack of efficacy, we may have to terminate them. If clinical trials are halted, or if they do not show that vosaroxin is safe and effective in the indications for which we are seeking regulatory approval, our future growth will be limited and we may not have any other product candidates to develop.

We do not know whether any future clinical trials with vosaroxin or any of our product candidates will be completed on schedule, or at all, or whether our ongoing or planned clinical trials will begin or progress on the time schedule we anticipate. The commencement of future clinical trials could be substantially delayed or prevented by several factors, including:

· delays or failures to raise additional funding;

· results of meetings with the FDA and/or other regulatory bodies;

· a limited number of, and competition for, suitable patients with particular types of cancer for enrollment in our clinical trials;

· delays or failures in obtaining regulatory approval to commence a clinical trial;

· delays or failures in obtaining sufficient clinical materials;

· delays or failures in obtaining approval from independent institutional review boards to conduct a clinical trial at prospective sites; or

· delays or failures in reaching acceptable clinical trial agreement terms or clinical trial protocols with prospective sites.

The completion of our clinical trials could be substantially delayed or prevented by several factors, including:

· delays or failures to raise additional funding;

· slower than expected rates of patient recruitment and enrollment;

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· failure of patients to complete the clinical trial;

· delays or failures in reaching the number of events pre-specified in the trial design;

· the need to expand the clinical trial;

· delays or failures in obtaining sufficient clinical materials, including vosaroxin, its matching placebo and cytarabine;

· unforeseen safety issues;

· lack of efficacy during clinical trials;

· inability or unwillingness of patients or clinical investigators to follow our clinical trial protocols; and

· inability to monitor patients adequately during or after treatment.

Additionally, our clinical trials may be suspended or terminated at any time by the FDA, other regulatory authorities, or ourselves. Any failure to complete or significant delay in completing clinical trials for our product candidates could harm our financial results and the commercial prospects for our product candidates.

We rely on a limited number of third-party manufacturers that are capable of manufacturing the vosaroxin active pharmaceutical ingredient, or API, and finished drug product, or FDP, to supply us with our vosaroxin API and FDP. If we fail to obtain sufficient quantities of these materials, the development and potential commercialization of vosaroxin could be halted or significantly delayed.

We do not currently own or operate manufacturing facilities and lack the capability to manufacture vosaroxin on a clinical or commercial scale. As a result, we rely on third parties to manufacture vosaroxin API and FDP. The vosaroxin API is classified as a cytotoxic substance, limiting the number of available manufacturers for both API and FDP.

We currently rely on two contract manufacturers for the vosaroxin API. We also currently rely on a single contract manufacturer to formulate the vosaroxin API and fill and finish vials of the vosaroxin FDP. If our third-party vosaroxin API or FDP manufacturers are unable or unwilling to produce the vosaroxin API or FDP we require, we would need to establish arrangements with one or more alternative suppliers. However, establishing a relationship with an alternative supplier would likely delay our ability to produce vosaroxin API or FDP. Our ability to replace an existing manufacturer would also be difficult and time consuming because the number of potential manufacturers is limited and the FDA must approve any replacement manufacturer before it can be an approved commercial supplier. Such approval would require new testing, stability programs and compliance inspections. It may be difficult or impossible for us to identify and engage a replacement manufacturer on acceptable terms in a timely manner, or at all. We expect to continue to depend on third-party contract manufacturers for all our vosaroxin API and FDP needs for the foreseeable future.

Vosaroxin requires precise, high quality manufacturing. For example, in the past, we observed visible particles during stability studies of two vosaroxin FDP lots which resulted from process impurities in the vosaroxin API that, when formulated into the packaged vial of the vosaroxin FDP, resulted in the formation of these particles. We have since addressed this issue by the implementation of a revised manufacturing process to control the impurities and thereby minimize particle formation, however, there is no assurance that similar issues will not arise in the future as we prepare for regulatory approval and potential commercialization of vosaroxin.

In addition to process impurities, the failure of our contract manufacturers to achieve and maintain high manufacturing standards in compliance with cGMP regulations could result in other manufacturing errors leading to patient injury or death, product recalls or withdrawals, delays or interruptions of production or failures in product testing or delivery. Although contract manufacturers are subject to ongoing periodic unannounced inspection by the FDA and corresponding state agencies to ensure strict compliance with cGMP and other applicable government regulations and corresponding foreign standards, any such performance failures on the part of a contract manufacturer could result in the delay or prevention of filing or approval of marketing applications for vosaroxin, cost overruns or other problems that could seriously harm our business. This would deprive us of potential product revenue and result in additional losses.

To date, vosaroxin has been manufactured in quantities appropriate for preclinical studies and clinical trials, including the manufacture of registration batches of API and FDP. Prior to commercial sale, we will need to perform process validation studies on API and FDP batches. If the results of these process validation studies do not meet preset criteria, the regulatory approval or commercial launch of vosaroxin may be delayed.

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The failure to enroll patients for clinical trials may cause delays in developing vosaroxin.

We may encounter delays if we are unable to enroll enough patients to complete clinical trials of vosaroxin. We completed enrollment of the VALOR trial in September 2013, but we may be required to enroll patients for additional clinical trials required by the FDA or other regulatory authorities. Patient enrollment depends on many factors, including the size of the patient population, the nature of the protocol, the proximity of patients to clinical sites, the number and nature of competing treatments and ongoing clinical trials of competing drugs for the same indication, and the eligibility criteria for the trial. Patients participating in our trials may elect to leave our trials and switch to alternative treatments that are available to them, either commercially or on an expanded access basis, or in other clinical trials. Competing treatments include nucleoside analogs, anthracyclines and hypomethylating agents. Moreover, when one product candidate is evaluated in multiple clinical trials simultaneously, patient enrollment in ongoing trials can be adversely affected by negative results from completed trials.

The results of preclinical studies and clinical trials may not satisfy the requirements of the FDA, EMA or other regulatory agencies.

Prior to receiving approval to commercialize vosaroxin or future product candidates, if any, in the United States or internationally, we must demonstrate with substantial evidence from well-controlled clinical trials, to the satisfaction of the FDA, EMA and other regulatory authorities, that such product candidates are safe and effective for their intended uses. The results from preclinical studies and clinical trials can be interpreted in different ways, and the VALOR trial failed to meet its primary endpoint. Even if we believe the preclinical or clinical data are promising, such data may not be sufficient to support approval by the FDA, EMA and other regulatory authorities.

We rely on third parties to conduct our clinical trials. If these third parties do not successfully carry out their contractual duties or fail to meet expected deadlines, we may be unable to obtain regulatory approval for, or commercialize, vosaroxin.

We rely on third parties, such as contract research organizations, medical institutions, clinical investigators and contract laboratories, to conduct our planned and existing clinical trials for vosaroxin. If the third parties conducting our clinical trials do not perform their contractual duties or obligations, do not meet expected deadlines or need to be replaced, or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical trial protocols or for any other reason, we may need to enter into new arrangements with alternative third parties and our clinical trials may be extended, delayed or terminated or may need to be repeated, and we may not be able to obtain regulatory approval for or commercialize the product candidate being tested in such trials.

We may expand our development capabilities in the future, and any difficulties hiring or retaining key personnel or managing this growth could disrupt our operations.

We are highly dependent on the principal members of our development staff. We may expand our research and development capabilities in the future by increasing expenditures in these areas, hiring additional employees and potentially expanding the scope of our current operations. Future growth will require us to continue to implement and improve our managerial, operational and financial systems and continue to retain, recruit and train additional qualified personnel, which may impose a strain on our administrative and operational infrastructure. The competition for qualified personnel in the biopharmaceutical field is intense. We are highly dependent on our continued ability to attract, retain and motivate highly qualified management and specialized personnel required for clinical development. Due to our limited resources, we may not be able to effectively manage any expansion of our operations or recruit and train additional qualified personnel. If we are unable to retain key personnel or manage our growth effectively, we may not be able to implement our business plan.

If we are sued for infringing intellectual property rights of third parties, litigation will be costly and time consuming and could prevent us from developing or commercializing vosaroxin.

Our commercial success depends on not infringing the patents and other proprietary rights of third parties and not breaching any collaboration or other agreements we have entered into with regard to our technologies and product candidates. If a third party asserts that we are using technology or compounds claimed in issued and unexpired patents owned or controlled by the third party, we may need to obtain a license, enter into litigation to challenge the validity of the patents or incur the risk of litigation in the event that a third party asserts that we infringe its patents.

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If a third party asserts that we infringe its patents or other proprietary rights, we could face a number of challenges that could seriously harm our competitive position, including:

· infringement and other intellectual property claims, which would be costly and time consuming to litigate, whether or not the claims have merit, and which could delay the regulatory approval process and divert management’s attention from our business;

· substantial damages for past infringement, which we may have to pay if a court determines that vosaroxin or any future product candidates infringe a third party’s patent or other proprietary rights;

· a court order prohibiting us from selling or licensing vosaroxin or any future product candidates unless a third party licenses relevant patent or other proprietary rights to us, which it is not required to do; and

· if a license is available from a third party, we may have to pay substantial royalties or grant cross-licenses to our patents or other proprietary rights.

If our competitors develop and market products that are more effective, safer or less expensive than vosaroxin, our commercial opportunities will be negatively impacted.

The life sciences industry is highly competitive, and we face significant competition from many pharmaceutical, biopharmaceutical and biotechnology companies that are researching, developing and marketing products designed to address the treatment of cancer, including AML, MDS and B-cell malignancies. Many of our competitors have significantly greater financial, manufacturing, marketing and drug development resources than we do. Large pharmaceutical companies in particular have extensive experience in the clinical testing of, obtaining regulatory approvals for, and marketing drugs.

We believe that our ability to successfully compete in the marketplace with vosaroxin and any future product candidates, if any, will depend on, among other things:

· our ability to develop novel compounds with attractive pharmaceutical properties and to secure, protect and maintain intellectual property rights based on our innovations;

· the efficacy, safety and reliability of our product candidates;

· the speed at which we develop our product candidates;

· our ability to design and successfully execute appropriate clinical trials;

· our ability to maintain a good relationship with regulatory authorities;

· our ability to obtain, and the timing and scope of, regulatory approvals;

· our ability to manufacture and sell commercial quantities of future products to the market;

· the availability of reimbursement from government agencies and private insurance companies; and

· acceptance of future products by physicians and other healthcare providers.

Vosaroxin is a small molecule therapeutic that, if approved, will compete with other drugs and therapies currently used for AML, such as nucleoside analogs, anthracyclines, hypomethylating agents, other inhibitors of topoisomerase II, and other novel agents. Additionally, other compounds currently in development could become potential competitors of vosaroxin, if approved for marketing.

If approved, we expect competition for vosaroxin for the treatment of AML and other potential future indications to increase as additional products are developed and approved in various patient populations. If our competitors market products that are more effective, safer or less expensive than vosaroxin or our other future products, if any, or that reach the market sooner we may not achieve commercial success or substantial market penetration. In addition, the biopharmaceutical industry is characterized by rapid change. Products developed by our competitors may render vosaroxin or any future product candidates obsolete.

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Our proprietary rights may not adequately protect vosaroxin or future product candidates, if any.

Our commercial success will depend on our ability to obtain patents and maintain adequate protection for vosaroxin and any future product candidates in the United States and other countries. We own, co-own or have rights to a significant number of issued U.S. and foreign patents and pending U.S. and foreign patent applications. We will be able to protect our proprietary rights from unauthorized use by third parties only to the extent that our proprietary technologies and future products are covered by valid and enforceable patents or are effectively maintained as trade secrets or are subject to marketing exclusivity administered by regulatory authorities.

We apply for patents covering both our technologies and product candidates, as we deem appropriate. However, we may fail to apply for patents on important technologies or product candidates in a timely fashion, or at all. Our existing patents and any future patents we obtain may not be sufficiently broad, valid, or enforceable to prevent others from practicing our technologies or from developing competing products and technologies. In addition, we generally do not exclusively control the patent prosecution of subject matter that we license to or from others. Accordingly, in such cases we are unable to exercise the same degree of control over this intellectual property as we would over our own. Moreover, the patent positions of biopharmaceutical companies are highly uncertain and involve complex legal and factual questions for which important legal principles remain unresolved. As a result, the scope, validity and enforceability of patents can vary from country to country, and can change depending on changes in national and international law, and as such, cannot be predicted with certainty. In addition, we do not know whether:

· we, our licensors or our collaboration partners were the first to make the inventions covered by each of our issued patents and pending patent applications;

· we, our licensors or our collaboration partners were the first to file patent applications for these inventions;

· others will independently develop similar or alternative technologies or duplicate any of our technologies;

· any of our, our licensors’ or our collaboration partners’ pending patent applications will result in issued patents;

· any of our, our licensors’ or our collaboration partners’ patents will be valid or enforceable;

· because of differences in patent laws of countries, any patent granted in one country or region will be granted in another, or, if so, have the same or a different scope;

· any patents issued to us, our licensors or our collaboration partners will provide us with any competitive advantages, or will be challenged by third parties;

· we will develop additional proprietary technologies that are patentable; or

· any patents or other proprietary rights of third parties will have an adverse effect on our business.

We also rely on trade secrets to protect some of our technology, especially where we do not believe patent protection is appropriate or obtainable. However, trade secrets are difficult to maintain. While we use reasonable efforts to protect our trade secrets, our or our collaboration partners’ employees, consultants, contractors or scientific and other advisors, or those of our licensors or collaborators, may unintentionally or willfully disclose our proprietary information to competitors. Enforcement of claims that a third party has illegally obtained and is using trade secrets is expensive, time consuming and uncertain. In addition, foreign courts are sometimes less willing than U.S. courts to protect trade secrets. If our competitors independently develop equivalent knowledge, methods and know-how, we would not be able to assert our trade secret protection against them and our business could be harmed.

The initial composition-of-matter patents covering vosaroxin are due to expire in 2015. While we continue to seek additional patent protection for vosaroxin and methods of its manufacture and use, even if vosaroxin is approved by the FDA and foreign equivalents thereof, we may not be able to recover our development costs prior to the expiration of any patents that are granted.

The vosaroxin composition-of-matter is covered by U.S. Patent No. 5,817,669 and its counterpart patents in 43 foreign jurisdictions. This U.S. patent is due to expire in October 2015, and most of its foreign counterparts are due to expire in June 2015. While it is possible that patent term restoration and/or supplemental patent certificates would be available for some of these or other patents we own or control through licenses, we cannot guarantee that such additional protection will be obtained, and the expiration dates described here do not include such term restoration.

We have been granted additional patents relating to vosaroxin compositions, and uses and manufacture of vosaroxin, in the U.S.:

· U.S. Patent No. 7,989,468 claims methods of use of vosaroxin at clinically relevant dose ranges and schedules for the treatment of leukemia, with expiry in 2026;

· U.S. Patent Nos. 7,829,577 and 8,669,270 claim certain pharmaceutical compositions of vosaroxin, including the formulation used in our VALOR trial, with expiry in 2025;

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· U.S. Patent No. 8,580,814 claims certain methods of use of vosaroxin at clinically relevant dose ranges to treat acute myelogenous leukemia, with expiry in 2026;

· U.S. Patent No. 8,822,493 claims certain methods of use of vosaroxin at clinically relevant dose ranges together with therapeutically effective amounts of cytarabine to treat cancer, with expiry in 2024;

· U.S. 8,124,773 B2 claims a hydrate of vosaroxin with expiry in 2028 and U.S. Patent No. 8,765,954 claims certain compositions containing this hydrate of vosaroxin, with expiry in 2027;

· U.S. Patent No. 8,497,282 claims a method of making vosaroxin, with expiry in 2031 and U.S. Patent No. 8,802,719 claims certain intermediates useful in the making of vosaroxin, with expiry in 2029;

· U.S. Patent Nos. 8,586,601 and 8,138,202 claim certain compositions containing vosaroxin, with expiry in 2030; and

· U.S. Patent No. 7,968,565 claims a combination of vosaroxin and cytarabine, with expiry in 2026.

We have been granted additional patents relating to vosaroxin compositions, and uses and manufacture of vosaroxin, in Europe:

· EPO Patent No. 1725233 B1, which has been validated in multiple EPO member states, claims certain pharmaceutical compositions of vosaroxin, including the formulation used in our VALOR trial, with expiry in 2025; and

· EP Patent No. 1729770 B1, which has been validated in multiple EPO member states, claims combinations of vosaroxin and certain anticancer agents, including cytarabine, with expiry in 2025.

In addition to the listed US and European patents, we have been granted similar and related patents in certain other countries, and patent applications are pending in these and other countries, including major markets, throughout the world.  In addition, other patents have been granted in the US and other countries claiming certain technology related to vosaroxin and other methods of use of vosaroxin.

We do not know when, if ever, vosaroxin will be approved by the FDA or foreign regulatory authorities. Even if vosaroxin is approved for commercial marketing in the future, we may not have sufficient time to commercialize our vosaroxin product to enable us to recover our development costs prior to the expiration of the U.S. and foreign patents covering vosaroxin. We do not know whether patent term extensions and data exclusivity periods will be available in the future for any or all of the patents we own or have licensed. Our obligation to pay royalties to Sumitomo Dainippon Pharma Co., Ltd., the company from which we licensed vosaroxin, may extend beyond the patent expiration, which would further erode the profitability of this product. In addition, our potential obligation to pay RPI royalties pursuant to the Royalty Agreement would also further erode the profitability of this product.

Any future workforce and expense reductions may have an adverse impact on our internal programs, our ability to hire and retain key personnel and may be distracting to management.

We have, in the past, implemented a number of workforce reductions. Depending on our need for additional funding and expense control, we may be required to implement further workforce and expense reductions in the future. Further workforce and expense reductions could result in reduced progress on our internal programs. In addition, employees, whether or not directly affected by a reduction, may seek future employment with our business partners or competitors. Although our employees are required to sign a confidentiality agreement at the time of hire, the confidential nature of certain proprietary information may not be maintained in the course of any such future employment. Further, we believe that our future success will depend in large part upon our ability to attract and retain highly skilled personnel. We may have difficulty retaining and attracting such personnel as a result of a perceived risk of future workforce and expense reductions. In addition, the implementation of expense reduction programs may result in the diversion of efforts of our executive management team and other key employees, which could adversely affect our business.

We may be subject to damages resulting from claims that we or our employees have wrongfully used or disclosed alleged trade secrets of our employees’ former employers.

Many of our employees were previously employed at biotechnology or pharmaceutical companies, including our competitors or potential competitors. We may be subject to claims that we or our employees have inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers. Litigation may be necessary to defend against these claims. If we fail in defending such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel.

A loss of key personnel or the work product of current or former personnel could hamper or prevent our ability to commercialize vosaroxin, which could severely harm our business. Even if we are successful in defending against these claims, litigation could result in substantial costs and be a distraction to management.

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We currently have limited marketing staff and no sales or distribution organization. If we are unable to develop a sales and marketing and distribution capability on our own, by contracting with third parties or through collaborations with marketing partners, we will not be successful in commercializing vosaroxin.

We currently have no sales or distribution capabilities and a limited marketing staff. If we are able to pursue and obtain marketing approval for vosaroxin in the U.S., we will plan to establish our own sales and marketing organization with technical expertise and supporting distribution capabilities to commercialize vosaroxin in North America, and potentially in Europe, which will be expensive and time consuming. Any failure or delay in the development of our internal or subcontracted sales, marketing and distribution capabilities would adversely impact the commercialization of these products. We plan to collaborate with third parties that have direct sales forces and established distribution systems in certain territories as part of the commercialization of vosaroxin. To the extent that we enter into co-promotion or other licensing arrangements, our product revenue is likely to be lower than if we marketed or sold vosaroxin directly. In addition, any revenue we receive will depend upon the efforts of third parties, which may not be successful and are only partially within our control. If we are unable to enter into such arrangements on acceptable terms or at all, we may not be able to successfully commercialize vosaroxin. If we are not successful in commercializing vosaroxin or our future product candidates, if any, either on our own or through collaborations with one or more third parties, our future product revenue will suffer and we may incur significant additional losses.

We depend on various consultants and advisors for the success and continuation of our development efforts.

We work extensively with various consultants and advisors, who provide advice and/or services in various business and development functions, including clinical development, operations and strategy, regulatory matters, biostatistics, legal and finance. The potential success of our drug development programs depends, in part, on continued collaborations with certain of these consultants and advisors. Our consultants and advisors are not our employees and may have commitments and obligations to other entities that may limit their availability to us. We do not know if we will be able to maintain such relationships or that such consultants and advisors will not enter into other arrangements with competitors, any of which could have a detrimental impact on our development objectives and our business.

If conflicts of interest arise between our current or future licensees or collaboration partners, if any, and us, any of them may act in their self-interest, which may be adverse to our interests.

If a conflict of interest arises between us and one or more of our current or potential future licensees or collaboration partners, if any, they may act in their own self-interest or otherwise in a way that is not in the interest of our company or our stockholders. Biogen Idec, Millennium, or potential future licensees or collaboration partners, if any, are conducting or may conduct product development efforts within the disease area that is the subject of a license or collaboration with our company. In current or potential future licenses or collaborations, if any, we have agreed or may agree not to conduct, independently or with any third party, any research that is competitive with the research conducted under our licenses or collaborations. Our licensees or collaboration partners, however, may develop, either alone or with others, products in related fields that are competitive with the product candidates that are the subject of these licenses or collaborations. Competing products, either developed by our licensees or collaboration partners or to which our licensees or collaboration partners have rights, may result in their withdrawal of support for a product candidate covered by the license or collaboration agreement.

If one or more of our current or potential future licensees or collaboration partners, if any, were to breach or terminate their license or collaboration agreements with us or otherwise fail to perform their obligations thereunder in a timely manner, the preclinical or clinical development or commercialization of the affected product candidates could be delayed or terminated. We do not know whether our licensees or collaboration partners will pursue alternative technologies or develop alternative product candidates, either on their own or in collaboration with others, including our competitors, as a means for developing treatments for the diseases targeted by licenses or collaboration agreements with our company.

Compliance with changing regulation of corporate governance and public disclosure may result in additional expenses.

Changing laws, regulations and standards relating to corporate governance and public disclosure may create uncertainty regarding compliance matters. New or changed laws, regulations and standards are subject to varying interpretations in many cases. As a result, their application in practice may evolve over time. We are committed to maintaining high standards of corporate governance and public disclosure. Complying with evolving interpretations of new or changed legal requirements may cause us to incur higher costs as we revise current practices, policies and procedures, and may divert management time and attention from potential revenue-generating activities to compliance matters. If our efforts to comply with new or changed laws, regulations and standards differ from the activities intended by regulatory or governing bodies due to ambiguities related to practice, our reputation may also be harmed. Further, our board members, chief executive officer and chief financial officer could face an increased risk of personal liability in connection with the performance of their duties. As a result, we may have difficulty attracting and retaining qualified board members and executive officers, which could harm our business.

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Raising funds through lending arrangements or revenue participation agreements may restrict our operations or produce other adverse results.

Our loan and security agreement, or the Loan Agreement, with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, or collectively, the Lenders, which we entered into on October 18, 2011, contains a variety of affirmative and negative covenants, including required financial reporting, limitations on certain dispositions of assets, limitations on the incurrence of additional debt and other requirements. To secure our performance of our obligations under this Loan Agreement, on October 18, 2011, we granted a perfected first priority security interest in substantially all of our assets, other than intellectual property assets, to the Lenders. Additionally, following the purchase of the revenue participation right by RPI on September 18, 2012, we granted both the Lenders and RPI a security interest in certain of our assets, including our intellectual property related to vosaroxin, which may only be perfected following first product approval in any country or territory. The Lenders will retain a senior position to RPI’s security interest for so long as any indebtedness under the Loan Agreement remains outstanding. Our failure to comply with the covenants in the Loan Agreement, the occurrence of a material impairment in our prospect of repayment or in the perfection or priority of the Lender’s lien on our assets, as determined by the Lenders, or the occurrence of certain other specified events could result in an event of default that, if not cured or waived, could result in the acceleration of all or a substantial portion of our debt, potential foreclosure on our assets and other adverse results.

In addition, following the purchase of the revenue participation right by RPI, we are required to pay RPI a specified percentage of any net sales of vosaroxin. If we fail to make timely payments due to RPI under the Royalty Agreement, RPI may require us to repurchase the revenue participation right. As collateral for these payments, we granted RPI a security interest in certain of our assets, including our intellectual property related to vosaroxin, as detailed above.

Economic conditions may make it costly and difficult to raise additional capital.

Recent volatility in the U.S. stock market and reduced credit availability may make investors unwilling to buy certain corporate stocks and bonds. If economic conditions affect the capital markets, our ability to raise capital via our existing controlled equity facility, new equity or debt financing arrangements, or otherwise, may be adversely affected.

We are exposed to risks related to foreign currency exchange rates and European sovereign debt.

Some of our costs and expenses are denominated in foreign currencies. Most of our foreign expenses are associated with activities related to the VALOR trial which occurred outside of the United States, and in particular in Western Europe. When the U.S. dollar weakens against the Euro or British pound, the U.S. dollar value of the foreign currency denominated expense increases, and when the U.S. dollar strengthens against the Euro or British pound, the U.S. dollar value of the foreign currency denominated expense decreases. Consequently, changes in exchange rates, and in particular a weakening of the U.S. dollar, may adversely affect our results of operations. We have and may continue to purchase certain European currencies or highly-rated investments denominated in such currencies to manage the risk of future movements in foreign exchange rates that would affect such payables, in accordance with our investment policy. However, there is no guarantee that the related gains and losses will substantially offset each other, and we may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter.

In addition, the recent sovereign debt crisis concerning certain European countries and related European financial restructuring efforts has and may continue to cause the value of the Euro to deteriorate. Such deterioration could adversely impact any investments we hold that are denominated in Euros. Rating agency downgrades on European sovereign debt and any potential default of European government issuers further contribute to this uncertainty. Should governments default on their obligations, we may experience loss of principal on any investments in European sovereign debt.

Our facilities are located near known earthquake fault zones, and the occurrence of an earthquake or other catastrophic disaster, or interruption by man-made problems such as network security breaches, viruses or terrorism, could cause damage to our facilities and equipment, which could require us to cease or curtail operations.

Our facilities are located in the San Francisco Bay Area near known earthquake fault zones and are vulnerable to significant damage from earthquakes. We are also vulnerable to damage from other types of disasters, including fires, floods, power loss, communications failures and similar events. Despite the implementation of network security measures, our networks also may be vulnerable to computer viruses, break-ins and similar disruptions.  We rely on information technology systems to operate our business and to communicate among our workforce and with third parties. If any disruption were to occur, whether caused by a natural disaster or by manmade problems, our ability to operate our business at our facilities may be seriously or completely impaired and our data could be lost or destroyed.

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Risks Related to Our Industry

The regulatory approval process is expensive, time consuming and uncertain and may prevent us from obtaining approval for the commercialization of vosaroxin.

The research, testing, manufacturing, selling and marketing of product candidates are subject to extensive regulation by the FDA and other regulatory authorities in the United States and other countries, which regulations differ from country to country. Neither we nor our present or potential future collaboration or licensing partners, if any, are permitted to market our product candidates in the United States until we receive approval of a new drug application, or NDA, from the FDA, or in any other country without the equivalent marketing approval from such country. We have not received marketing approval for vosaroxin in any jurisdiction. In addition, failure to comply with FDA and other applicable U.S. and foreign regulatory requirements may subject us to administrative or judicially imposed sanctions, including warning letters, civil and criminal penalties, injunctions, product seizure or detention, product recalls, total or partial suspension of production, and refusal to approve pending NDAs, supplements to approved NDAs or their foreign equivalents.

Regulatory approval of an NDA or NDA supplement or a foreign equivalent is not guaranteed, and the approval process is expensive, uncertain and may take several years. Furthermore, the development process for oncology products may take longer than in other therapeutic areas. Regulatory authorities have substantial discretion in the drug approval process. Despite the time and expense exerted, failure can occur at any stage, and we could encounter problems that cause us to abandon clinical trials or to repeat or perform additional preclinical studies and clinical trials. The number of preclinical studies and clinical trials that will be required for marketing approval varies depending on the drug candidate, the disease or condition that the drug candidate is designed to address, and the regulations applicable to any particular drug candidate. In particular, the VALOR trial failed to meet its primary endpoint, and the FDA may require us to conduct additional clinical trials before or after any approval is granted of vosaroxin for the treatment of AML.

The FDA or a foreign regulatory authority can delay, limit or deny approval of a drug candidate for many reasons, including:

· the drug candidate may not be deemed safe or effective;

· regulatory officials may not find the data from preclinical studies and clinical trials sufficient;

· the FDA or foreign regulatory authority might not approve our or our third-party manufacturers’ processes or facilities; or

· the FDA or foreign regulatory authority may change its approval policies or adopt new regulations.

We may be subject to costly claims related to our clinical trials and may not be able to obtain adequate insurance.

Because we conduct clinical trials in humans, we face the risk that the use of vosaroxin or future product candidates, if any, will result in adverse side effects. We cannot predict the possible harms or side effects that may result from our clinical trials. Although we have clinical trial liability insurance for up to $10.0 million in the aggregate, our insurance may be insufficient to cover any such events. We do not know whether we will be able to continue to obtain clinical trial coverage on acceptable terms, or at all. We may not have sufficient resources to pay for any liabilities resulting from a claim excluded from, or beyond the limit of, our insurance coverage. There is also a risk that third parties that we have agreed to indemnify could incur liability. Any litigation arising from our clinical trials, even if we were ultimately successful, would consume substantial amounts of our financial and managerial resources and may create adverse publicity.

Even if we receive regulatory approval to sell vosaroxin, the market may not be receptive to vosaroxin.

Even if vosaroxin obtains regulatory approval, it may not gain market acceptance among physicians, patients, healthcare payors and/or the medical community. We believe that the degree of market acceptance will depend on a number of factors, including:

· timing of market introduction of competitive products;

· efficacy of our product;

· prevalence and severity of any side effects;

· potential advantages or disadvantages over alternative treatments;

· strength of marketing and distribution support;

· price of vosaroxin, both in absolute terms and relative to alternative treatments; and

· availability of reimbursement from health maintenance organizations and other third-party payors.

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For example, the potential toxicity of single and repeated doses of vosaroxin has been explored in a number of animal studies that suggest the dose-limiting toxicities in humans receiving vosaroxin may be similar to some of those observed with approved cytotoxic agents, including reversible toxicity to bone marrow cells, the gastrointestinal system and other systems with rapidly dividing cells. In our Phase 1, Phase 2 and VALOR clinical trials of vosaroxin, we have witnessed the following side effects, irrespective of causality, ranging from mild to more severe: lowered white blood cell count that may lead to a serious or possibly life-threatening infection, hair loss, mouth sores, fatigue, nausea with or without vomiting, lowered platelet count, which may lead to an increase in bruising or bleeding, lowered red blood cell count (anemia), weakness, tiredness, shortness of breath, diarrhea and intestinal blockage.

If vosaroxin fails to achieve market acceptance, due to unacceptable side effects or any other reasons, we may not be able to generate significant revenue or to achieve or sustain profitability.

Even if we receive regulatory approval for vosaroxin, we will be subject to ongoing FDA and other regulatory obligations and continued regulatory review, which may result in significant additional expense and limit our ability to commercialize vosaroxin.

Any regulatory approvals that we or our potential future collaboration partners receive for vosaroxin or our future product candidates, if any, may also be subject to limitations on the indicated uses for which the product may be marketed or contain requirements for potentially costly post-marketing trials. In addition, even if approved, the labeling, packaging, adverse event reporting, storage, advertising, promotion and recordkeeping for any product will be subject to extensive and ongoing regulatory requirements. The subsequent discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, may result in restrictions on the marketing of the product, and could include withdrawal of the product from the market.

Regulatory policies may change and additional government regulations may be enacted that could prevent or delay regulatory approval of our product candidates. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad. If we are not able to maintain regulatory compliance, we might not be permitted to market vosaroxin or our future products and we may not achieve or sustain profitability.

The coverage and reimbursement status of newly approved drugs is uncertain, and failure to obtain adequate coverage and reimbursement could limit our ability to market vosaroxin and decrease our ability to generate revenue.

There is significant uncertainty related to the third party coverage and reimbursement of newly approved drugs both nationally and internationally. The commercial success of vosaroxin and our future products, if any, in both domestic and international markets depends on whether third-party coverage and reimbursement is available for the ordering of our future products by the medical profession for use by their patients. Medicare, Medicaid, health maintenance organizations and other third-party payors are increasingly attempting to manage healthcare costs by limiting both coverage and the level of reimbursement of new drugs and, as a result, they may not cover or provide adequate payment for our future products. These payors may not view our future products as cost-effective, and reimbursement may not be available to consumers or may not be sufficient to allow our future products to be marketed on a competitive basis. Likewise, legislative or regulatory efforts to control or reduce healthcare costs or reform government healthcare programs could result in lower prices or rejection of our future products. Changes in coverage and reimbursement policies or healthcare cost containment initiatives that limit or restrict reimbursement for our future products may reduce any future product revenue.

Failure to obtain regulatory approval in foreign jurisdictions will prevent us from marketing vosaroxin abroad.

We intend to market vosaroxin in international markets either directly or through a potential future collaboration partner, if any. In order to market vosaroxin in the European Union, Canada and many other foreign jurisdictions, we or a potential future collaboration partner must obtain separate regulatory approvals. We have, and potential future collaboration partners may have, had limited interactions with foreign regulatory authorities, and the approval procedures vary among countries and can involve additional testing at significant cost. The time required to obtain approval may differ from that required to obtain FDA approval. Approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. The foreign regulatory approval processes may include all of the risks associated with obtaining FDA approval. We or a potential future collaboration partner may not obtain foreign regulatory approvals on a timely basis, if at all. We or a potential future collaboration partner may not be able to file for regulatory approvals and may not receive necessary approvals to commercialize vosaroxin or any other future products in any market.

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Foreign governments often impose strict price controls, which may adversely affect our future profitability.

We intend to seek approval to market vosaroxin in both the United States and foreign jurisdictions either directly or through one or more potential future collaboration partners. If we or a potential future collaboration partner obtain approval in one or more foreign jurisdictions, we or the potential future collaboration partner will be subject to rules and regulations in those jurisdictions relating to vosaroxin. In some foreign countries, particularly in the European Union, prescription drug pricing is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a drug candidate. To obtain reimbursement or pricing approval in some countries, we or a potential future collaboration partner may be required to conduct a clinical trial that compares the cost-effectiveness of vosaroxin to other available therapies. If reimbursement of vosaroxin is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, we may be unable to achieve or sustain profitability.

We may incur significant costs complying with environmental laws and regulations, and failure to comply with these laws and regulations could expose us to significant liabilities.

We, through third-party contractors, use hazardous chemicals and radioactive and biological materials in our business and are subject to a variety of federal, state, regional and local laws and regulations governing the use, generation, manufacture, storage, handling and disposal of these materials. Although we believe our safety procedures for handling and disposing of these materials and waste products comply with these laws and regulations, we cannot eliminate the risk of accidental injury or contamination from the use, storage, handling or disposal of hazardous materials. In the event of contamination or injury, we could be held liable for any resulting damages, and any liability could significantly exceed our insurance coverage, which is limited for pollution cleanup and contamination.

Risks Related to Our Common Stock

The price of our common stock may continue to be volatile, and the value of an investment in our common stock may decline.

In 2014, our common stock traded as low as $1.00 and as high as $8.46. Factors that could cause continued volatility in the market price of our common stock include, but are not limited to:

· our ability to raise additional capital to carry through with our clinical development plans and current and future operations and the terms of any related financing arrangement;

· results from, and any delays in or discontinuance of, ongoing and planned clinical trials for vosaroxin, including investigator-sponsored trials;

· announcements of additional FDA requirements for a regulatory path for vosaroxin or non-approval of vosaroxin, delays in filing regulatory documents with the FDA or other regulatory agencies, or delays in the review process by the FDA or other foreign regulatory agencies;

· announcements relating to restructuring and other operational changes;

· delays in the commercialization of vosaroxin or our future products, if any;

· market conditions in the pharmaceutical, biopharmaceutical and biotechnology sectors;

· issuance of new or changed securities analysts’ reports or recommendations;

· developments or disputes concerning our intellectual property or other proprietary rights;

· clinical and regulatory developments with respect to potential competitive products;

· failure to maintain compliance with the covenants in the Loan Agreement;

· introduction of new products by our competitors;

· issues in manufacturing vosaroxin drug substance or drug product, or future products, if any;

· market acceptance of vosaroxin or our future products, if any;

· announcements relating to our arrangements with Biogen Idec, Millennium or RPI;

· actual and anticipated fluctuations in our quarterly operating results;

· deviations in our operating results from the estimates of analysts;

· third-party healthcare reimbursement policies;

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· FDA or other U.S. or foreign regulatory actions affecting us or our industry;

· litigation or public concern about the safety of vosaroxin or future products, if any;

· failure to develop or sustain an active and liquid trading market for our common stock;

· sales of our common stock by our officers, directors or significant stockholders; and

· additions or departures of key personnel.

Provisions of our charter documents or Delaware law could delay or prevent an acquisition of our company, even if the acquisition would be beneficial to our stockholders, and could make it more difficult to change management.

Provisions of our amended and restated certificate of incorporation and amended and restated bylaws may discourage, delay or prevent a merger, acquisition or other change in control that stockholders might otherwise consider favorable, including transactions in which stockholders might otherwise receive a premium for their shares. In addition, these provisions may frustrate or prevent any attempt by our stockholders to replace or remove our current management by making it more difficult to replace or remove our board of directors. These provisions include:

· a classified board of directors so that not all directors are elected at one time;

· a prohibition on stockholder action through written consent;

· limitations on our stockholders’ ability to call special meetings of stockholders;

· an advance notice requirement for stockholder proposals and nominations; and

· the authority of our board of directors to issue preferred stock with such terms as our board of directors may determine.

In addition, Delaware law prohibits a publicly held Delaware corporation from engaging in a business combination with an interested stockholder, generally a person who, together with its affiliates, owns or within the last three years has owned 15% of our voting stock, for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination is approved in a prescribed manner. Accordingly, Delaware law may discourage, delay or prevent a change in control of our company.

Provisions in our charter documents and provisions of Delaware law could limit the price that investors are willing to pay in the future for shares of our common stock.

We have never paid dividends on our capital stock and we do not anticipate paying any cash dividends in the foreseeable future.

We have never declared or paid cash dividends on our capital stock. We do not anticipate paying any cash dividends on our capital stock in the foreseeable future. In addition, under the terms of our Loan Agreement with the Lenders, we are precluded from paying cash dividends without the prior written consent of the Lenders. We currently intend to retain all available funds and any future earnings to fund the development and growth of our business. As a result, capital appreciation, if any, of our common stock will be our stockholders’ sole source of gain for the foreseeable future.

We are at risk of securities class action litigation.

In the past, securities class action litigation has often been brought against a company following a decline in the market price of its securities. This risk is especially relevant for us because biotechnology companies have experienced greater than average stock price volatility in recent years. These broad market fluctuations may adversely affect the trading price or liquidity of our common stock. In the past, when the market price of a stock has been volatile, holders of that stock have sometimes instituted securities class action litigation against the issuer. If any of our stockholders were to bring such a lawsuit against us, we could incur substantial costs defending the lawsuit and the attention of our management would be diverted from the operation of our business.

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The ownership of our capital stock is concentrated, and your interests may conflict with the interests of our existing stockholders.

Our executive officers and directors together with their affiliates beneficially owned approximately 19% of our outstanding capital stock as of December 31, 2014, assuming the exercise in full of the outstanding warrants to purchase common stock held by these stockholders as of such date. Accordingly, these stockholders, acting as a group, could have an influence over the outcome of corporate actions requiring stockholder approval, including the election of directors, any merger, consolidation or sale of all or substantially all of our assets or any other significant corporate transaction. The significant concentration of stock ownership may adversely affect the trading price of our common stock due to investors’ perception that conflicts of interest may exist or arise.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

ITEM 2. PROPERTIES

Our corporate headquarters is currently located at 395 Oyster Point Boulevard in South San Francisco, California. In January 2014, a lease for 15,378 square feet of office space at this location was entered into with an expiration date of April 30, 2015. In June 2014, the lease was amended to extend the expiration date to June 30, 2015, and to add 6,105 square feet of additional office space within the same building. In January 2015, the lease was further amended to extend the expiration date to December 31, 2015. We believe these facilities are adequate for our needs in 2015.

ITEM 3. LEGAL PROCEEDINGS

From time to time, we may be involved in routine legal proceedings, as well as demands, claims and threatened litigation, which arise in the normal course of our business. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on our results of operations and financial condition. Regardless of outcome, litigation can have an adverse impact on us because of the defense costs, diversion of management resources and other factors.

We believe there is no litigation pending that could, individually or in the aggregate, have a material adverse effect on our results of operations or financial condition.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

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PART II

ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Our common stock is listed on The NASDAQ Stock Market under the symbol “SNSS.” The following table sets forth the range of the high and low sales prices by quarter, as reported by NASDAQ.

Year-Ended December 31, 2013	High		Low
First Quarter	$	6.54	$	3.92
Second Quarter	$	6.00	$	4.71
Third Quarter	$	6.13	$	4.52
Fourth Quarter	$	5.38	$	4.53

Year-Ended December 31, 2014	High		Low
First Quarter	$	7.49	$	3.84
Second Quarter	$	7.24	$	4.53
Third Quarter	$	8.46	$	5.46
Fourth Quarter	$	7.15	$	1.00

As of February 27, 2015, there were approximately 148 holders of record of our common stock. In addition, we believe that a significant number of beneficial owners of our common stock hold their shares in nominee or in “street name” accounts through brokers. On February 27, 2015, the last sale price reported on The NASDAQ Stock Market for our common stock was $2.22 per share.

Dividend Policy

We have never paid cash dividends on our common stock. We do not anticipate paying any cash dividends on our capital stock in the foreseeable future. While subject to periodic review, the current policy of our board of directors is to retain cash and investments primarily to provide funds for our future growth. In addition, under the terms of our loan and security agreement with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, we are precluded from paying cash dividends without the prior written consent of the lenders.

Recent Sales of Unregistered Securities

None.

Stock Performance Graph

The following stock performance graph compares the cumulative total return to security holders of our common shares with the comparable cumulative returns of the NASDAQ Composite Index and the NASDAQ Biotechnology Index. The graph assumes the investment of $100 on December 31, 2009 and the reinvestment of all dividends, if any. Points on the graph represent the performance as of the last business day of each of the fiscal years indicated.

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The following performance graph is not “soliciting material,” is not deemed filed with the SEC and is not to be incorporated by reference in any filing by us under the Securities Act of 1933, as amended, or the Securities Act, or the Exchange Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing. The stock price performance shown on the graph is not necessarily indicative of future price performance.

COMPARISON OF 5 YEAR CUMULATIVE TOTAL RETURN*

Among Sunesis Pharmaceuticals, Inc., the NASDAQ Composite Index, and the NASDAQ Biotechnology Index

* $100 invested on December 31, 2009 in stock or index, including reinvestment of any dividends.

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ITEM 6. SELECTED FINANCIAL DATA

The following selected financial data should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements and notes to those statements included elsewhere in this report. The historical results presented below are not necessarily indicative of future results.

	Year Ended December 31,
Consolidated Statements of Operations:	2014			2013			2012			2011			2010
	(In thousands, except per share amounts)
Revenue:
Collaboration revenue	$	—		$	—		$	—		$	—		$	27
License and other revenue		5,734			7,956			3,754			5,000			6
Total revenues		5,734			7,956			3,754			5,000			33
Operating expenses:
Research and development		27,665			28,891			29,185			22,563			14,433
General and administrative		23,112			10,838			9,175			8,303			7,005
Total operating expenses		50,777			39,729			38,360			30,866			21,438
Loss from operations		(45,043	)		(31,773	)		(34,606	)		(25,866	)		(21,405	)
Interest expense		(1,719	)		(2,917	)		(1,855	)		(259	)		—
Other income (expense), net(1)		3,760			92			(7,490	)		5,984			(3,182	)
Net loss	$	(43,002	)	$	(34,598	)	$	(43,951	)	$	(20,141	)	$	(24,587	)
Basic and diluted loss per common share:
Net loss:
Basic	$	(43,002	)	$	(34,598	)	$	(43,951	)	$	(20,141	)	$	(24,587	)
Diluted	$	(46,894	)	$	(34,598	)	$	(43,951	)	$	(20,141	)	$	(24,587	)
Shares used in computing net loss per common share:
Basic		60,057			52,249			48,146			46,412			24,860
Diluted		61,510			52,249			48,146			46,412			24,860
Net loss per common share:
Basic	$	(0.72	)	$	(0.66	)	$	(0.91	)	$	(0.43	)	$	(0.99	)
Diluted	$	(0.76	)	$	(0.66	)	$	(0.91	)	$	(0.43	)	$	(0.99	)

(1) During 2014, 2013, 2012, 2011 and 2010, we recorded net non-cash credits (charges) of $3.9 million, $0.1 million, $(7.5) million, $5.9 million and $(3.7) million, respectively, related to the revaluation of the liability for warrants issued in connection with the underwritten public offering of our common stock in October 2010 (see Note 10 of the accompanying consolidated financial statements).

	As of December 31,
Consolidated Balance Sheet Data:	2014			2013			2012			2011			2010
	(In thousands)
Cash, cash equivalents and marketable securities	$	42,981		$	39,293		$	71,227		$	44,115		$	53,396
Working capital		16,323			6,520			41,191			37,282			42,118
Total assets		44,246			40,525			73,017			45,869			54,858
Non-current portion of deferred revenue		2,563			3,712			11,668			—			—
Current portion of notes payable		9,257			9,018			6,610			—			—
Non-current portion of notes payable		—			9,025			17,651			9,453			—
Common stock and additional paid-in capital		536,506			473,514			457,016			429,147			423,267
Accumulated deficit		(522,697	)		(479,695	)		(445,097	)		(401,146	)		(381,005	)
Total stockholders’ equity (deficit)		13,802			(6,184	)		11,957			28,020			42,247

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ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis of our financial condition as of December 31, 2014 and results of operations for the year ended December 31, 2014 should be read together with our consolidated financial statements and related notes included elsewhere in this report.

This discussion and analysis contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the Private Securities Litigation Reform Act of 1995, which involve risks, uncertainties and assumptions. All statements, other than statements of historical facts, are “forward-looking statements” for purposes of these provisions, including without limitation any statements relating to our strategy, including regulatory plans to file a marketing authorization application with the European Medicines Agency, our preliminary analysis, assessment and conclusions of the results of the VALOR trial, and the commercial potential of vosaroxin, presenting clinical data and initiating clinical trials, our future research and development activities, including clinical testing and the costs and timing thereof, sufficiency of our cash resources, our ability to raise additional funding when needed, any statements concerning anticipated regulatory activities or licensing or collaborative arrangements, our research and development and other expenses, our operations and legal risks, and any statement of assumptions underlying any of the foregoing. In some cases, forward-looking statements can be identified by the use of terminology such as “anticipates,” “believe,” “continue,” “estimates,” “expects,” “intend,” “look forward,” “may,” “could,” “seeks,” “plans,” “potential,” or “will” or the negative thereof or other comparable terminology. Although we believe that the expectations reflected in the forward-looking statements contained herein are reasonable, there can be no assurance that such expectations or any of the forward-looking statements will prove to be correct, and actual results could differ materially from those projected or assumed in the forward-looking statements. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of many factors, including but not limited to those set forth under “Risk Factors,” and elsewhere in this report. We urge you not to place undue reliance on these forward-looking statements, which speak only as of the date of this report. All forward-looking statements included in this report are based on information available to us on the date of this report, and we assume no obligation to update any forward-looking statements contained in this report.

Overview

We are a biopharmaceutical company focused on the development and commercialization of our pipeline of new oncology therapeutics for the potential treatment of solid and hematologic cancers. Our most advanced program is QINPREZO^TM (vosaroxin), our product candidate for the potential treatment of acute myeloid leukemia, or AML. In October 2014, we announced the results of a Phase 3, multi-national, randomized, double-blind, placebo-controlled trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory AML, or the VALOR trial. The VALOR trial, which enrolled 711 adult patients, was designed to evaluate the effect of vosaroxin in combination with cytarabine, a widely used chemotherapy in AML, on overall survival as compared to placebo in combination with cytarabine, and was conducted at 124 study sites in the U.S., Canada, Europe, South Korea, Australia and New Zealand. Detailed results of the VALOR trial were presented in the "Late Breaking Abstracts" session of the American Society of Hematology (ASH) Annual Meeting in December 2014.

Patients treated with vosaroxin achieved increased overall survival compared to those treated with placebo (7.5 months vs 6.1 months, HR=0.87), the primary endpoint, but this difference did not achieve statistical significance (p=0.06). The complete remission (CR) rate, the sole secondary efficacy endpoint in the trial, did demonstrate a significant difference for the vosaroxin combination arm (30.1% vs 16.3%, p < 0.0001).

In a pre-planned analysis accounting for the stratification factors at randomization, a significant improvement in overall survival was demonstrated (HR=0.83, p=0.02). The pre-planned analysis of all treatment strata included the following difficult to treat patient categories: over 60 years old (7.1 months vs 5.0 months, HR=0.75, p=0.003, n=451), refractory disease (6.7 months vs 5.0 months, HR=0.87, p=0.23, n=301), and early relapsed disease (6.7 months vs 5.2 months, HR=0.77, p=0.04, n=256). Outcomes in patients under 60 years old or with late relapsed disease were comparable between treatment arms, with no improvement in overall survival. Across all strata, the CR and Composite CR (CR+CRp+CRi) rates were higher in the vosaroxin combination arm.

Given the complexity of interpreting the impact of transplantation therapy, a predefined analysis of overall survival censoring for hematopoietic stem cell transplantation was planned. In this analysis, patients receiving the vosaroxin combination had a median overall survival of 6.7 months versus 5.3 months for patients receiving placebo and cytarabine (HR=0.81, p=0.02).

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Regarding drug safety, Grade 3 or higher non-hematologic adverse events that were more common in the vosaroxin combination arm were gastrointestinal and infection-related toxicities, consistent with those observed in our previous clinical trials. The rate of serious adverse events was 55.5% in the vosaroxin combination arm compared to 35.7% in the placebo and cytarabine arm. 30-day and 60-day all-cause mortality were comparable between the trial arms (7.9% versus 6.6% and 19.7% versus 19.4%, for the vosaroxin combination versus placebo and cytarabine, respectively).

Based on the results of the VALOR trial, we have submitted a letter of intent to the European Medicines Agency, or EMA, describing our intention to file a marketing authorization application, or MAA, for marketing authorization of vosaroxin plus cytarabine for the treatment of relapsed or refractory AML. We plan to meet with European regulatory authorities in preparation for an MAA filing in the second half of 2015.We are also currently engaged in discussions with the U.S. Food and Drug Administration, or FDA, to determine a potential regulatory path forward in the United States.

In the second half of 2013, we announced the initiation of three Phase 1/2 investigator-sponsored trials of vosaroxin, either as a standalone therapy or in combination with approved compounds, in various indications of AML and high-risk myelodysplastic syndrome, or MDS. The trials are being conducted at the University of Texas MD Anderson Cancer Center, or MDACC, Weill Cornell Medical College and New York-Presbyterian Hospital, and the Washington University School of Medicine.

In December 2014, updated results from the ongoing Phase 1b/2 MDACC-sponsored trial of vosaroxin in combination with decitabine in older patients with previously untreated AML and high-risk MDS were presented at the ASH Annual Meeting. This trial is expected to enroll up to a combined total of approximately 70 patients.

In January 2014, we announced the expansion of our oncology franchise through separate global licensing agreements for two preclinical kinase inhibitor programs. The first agreement, with Biogen Idec, is for global commercial rights to SNS-062, a selective non-covalently binding oral inhibitor of BTK. We are currently conducting IND-enabling studies for SNS-062, with a view to filing an IND application with the FDA.

The second agreement, with Millennium, is for global commercial rights to several potential first-in class, pre-clinical inhibitors of the novel target PDK1. In 2014, we selected two PDK1 inhibitors, SNS-229 and SNS-510, of which we plan to take at least one into IND-enabling absorption, distribution, metabolism and excretion, or ADME, and safety studies in 2015.

Both BTK and PDK1 programs were originally developed under a research collaboration agreement between Biogen Idec and Sunesis. in 2011, the PDK1 program was purchased by and exclusively licensed to Millennium along with the more advanced program, MLN2480, a pan-RAF inhibitor currently in the maximum tolerated dose cohort expansion stage of a Millennium Phase 1, multicenter dose escalation study. We currently expect SNS-062 and the PDK1 inhibitors will be developed exclusively by Sunesis.

Recent Financial History

Equity Financing Agreements

In March 2014, we completed an underwritten offering of 4,650,000 shares of common stock, each with two accompanying warrants to purchase one share of our common stock at exercise prices of $8.50 (Series A) and $12.00 (Series B) per share, respectively. The purchase price for each share of common stock and two accompanying warrants was $9.25. Gross proceeds from the sale were $43.0 million and net proceeds were $40.0 million. The Series A warrants expired unexercised in December 2014. The Series B warrants will expire on or before the later of 30 days following the PDUFA date of the VALOR trial, if any, and September 4, 2015, but in no event later than March 4, 2016.

In August 2011, we entered into a Controlled Equity Offering^SM sales agreement, or the Sales Agreement, with Cantor Fitzgerald & Co., or Cantor, as agent and/or principal, pursuant to which we could issue and sell shares of our common stock having an aggregate gross sales price of up to $20.0 million. In April 2013, the Sales Agreement was amended to provide for an increase of $30.0 million in the aggregate gross sales price under the Sales Agreement. We will pay Cantor a commission of 3.0% of the gross proceeds from any common stock sold through the Sales Agreement, as amended.

During 2014, we sold an aggregate of 5,113,876 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.88 per share for gross proceeds of $14.7 million and net proceeds of $14.3 million, after deducting Cantor’s commission. In January and February 2015, the Company sold an aggregate of 1,579,124 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.75 per share for gross proceeds of $4.3 million and net proceeds of $4.2 million, after deducting Cantor’s commission. As of February 27, 2015, $2.5 million of common stock remained available to be sold under the Sales Agreement, as amended, subject to certain conditions as specified in the agreement.

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Loan Agreement

In October 2011, we entered into the Loan and Security Agreement, or the Loan Agreement, with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, or collectively, the Lenders, and received the first tranche of $10.0 million from the Lenders. In September 2012, following the recommendation by the Data Safety Monitoring Board, or DSMB, to increase the sample size for the VALOR trial, we drew the second tranche of $15.0 million from the Lenders. Payments under both tranches were interest-only until February 1, 2013, with the following 32 equal monthly payments of principal and interest being paid monthly in arrears through the scheduled maturity date of October 1, 2015. On February 27, 2015, the Loan Agreement was amended to provide for an interest-only period from March 1, 2015 to February 1, 2016, such that the eight remaining principal payments will be deferred and re-amortized over the period from March 1, 2016 to October 1, 2016.

Capital Requirements

We have incurred significant losses in each year since our inception. As of December 31, 2014, we had cash, cash equivalents and marketable securities of $43.0 million and an accumulated deficit of $522.7 million. We expect to continue to incur significant losses for the foreseeable future as we continue the development process and seek regulatory approvals for vosaroxin.

We will need to raise substantial additional capital to complete the development and potential commercialization of vosaroxin, and expect to finance our future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to vosaroxin, or a combination of the above. However, we do not know whether additional funding will be available on acceptable terms, or at all. If we are unable to raise required funding on acceptable terms or at all, we will need to reduce operating expenses, enter into a collaboration or other similar arrangement with respect to development and/or commercialization rights to vosaroxin, outlicense intellectual property rights to vosaroxin or our other development programs, sell unsecured assets, or a combination of the above, or be forced to delay or reduce the scope of our vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease our operations.

Critical Accounting Policies and the Use of Estimates

The accompanying discussion and analysis of our financial condition and results of operations are based on our consolidated financial statements and the related disclosures, which have been prepared in accordance with U.S. generally accepted accounting principles. The preparation of these consolidated financial statements requires our management to make estimates, assumptions and judgments that affect the amounts reported in our financial statements and accompanying notes, including reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, as well as revenue and expenses during the reporting periods. We evaluate our estimates, assumptions and judgments on an ongoing basis. We base our estimates on historical experience and on various other assumptions we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Management has discussed the development, selection and disclosure of these estimates with the Audit Committee of our Board of Directors. Actual results could differ materially from these estimates under different assumptions or conditions.

Our significant accounting policies are more fully described in Note 2 to our consolidated financial statements included elsewhere in this report. We believe the following critical accounting policies reflect our more significant estimates and assumptions used in the preparation of our consolidated financial statements.

Accounting for Equity Financing

In October 2010, we completed an underwritten offering, or the 2010 Offering, in which we sold our common stock and warrants to purchase our common stock for aggregate gross proceeds of $15.5 million. Due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements, the warrants are being accounted for as a derivative liability as opposed to permanent equity. Outstanding warrants under this arrangement are revalued to their fair value at each period end, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive (loss) income. The Black-Scholes model was selected as the most appropriate method to estimate both the initial and subsequent fair values of the warrants. The determination of initial and subsequent fair values is affected by our stock price as well as assumptions regarding a number of highly complex and subjective variables. Changes in these input variables have, and will continue to, affect the income or expense recorded each period for the revaluation of outstanding warrants. As a result, fluctuations in our stock price or other input variables may significantly affect our financial results.

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Accounting for Royalty Agreement

In March 2012, we entered into the Royalty Agreement with RPI, and in September 2012, as a result of the recommendation by the DSMB to increase the sample size for the VALOR trial, RPI made a $25.0 million cash payment to us in exchange for a 6.75% royalty on any future net sales of vosaroxin. In conjunction with the Royalty Agreement, we issued two five-year warrants to RPI, each to purchase 1,000,000 shares of our common stock.

The payment of $25.0 million by RPI is non-refundable, and no revenue participation right payments will be made unless vosaroxin is approved by regulatory authorities and subsequently commercialized. Accordingly, the payment, less a portion representing the fair value of the warrants of $3.1 million, is being accounted for as consideration for our commitment to use commercially reasonable efforts to commercialize vosaroxin. The net amount of $21.9 million has therefore been classified as deferred revenue and is being amortized to revenue over the related estimated performance period, and the fair value of the warrants has been recorded to additional paid-in capital. The Black-Scholes model was selected as the most appropriate method to estimate the fair value of the warrants. The Black-Scholes model requires several subjective inputs such as expected term and share price volatility, which require significant analysis and judgment to develop.

Revenue Recognition

Revenue arrangements with multiple deliverables are accounted for in accordance with Financial Accounting Standards Board Accounting Standards Codification Subtopic 605-25, Multiple-Element Arrangements, or ASC 605-25. Under ASC 605-25, revenue arrangements with multiple deliverables are divided into separate units of accounting based on whether certain criteria are met, including whether the delivered item has stand-alone value to the customer. Consideration is allocated among the separate units of accounting based on their respective fair value, and the applicable revenue recognition is applied to each of the separate units.

Non-refundable fees where we have no continuing performance obligations are recognized as revenues when collection is reasonably assured. In situations where continuing performance obligations exist, non-refundable fees are deferred and recognized ratably over the projected performance period.

Milestone payments from license or collaboration agreements which are substantive and at risk at the time the agreement is executed are recognized upon completion of the applicable milestone event. Royalty revenues, if any, will be recognized based on reported product sales by third-party licensees. Research funding from any future agreement will be recognized as the related research services are performed.

Clinical Trial Accounting

We record accruals for estimated clinical trial costs, which include payments for work performed by contract research organizations, or CROs, and participating clinical trial sites. These costs are generally a significant component of research and development expense. Costs incurred for setting up clinical trial sites for participation in trials are generally non-refundable, and are expensed as incurred, with any refundable advances related to enrollment of the first patient recorded as prepayments and assessed for recoverability on a quarterly basis. Costs related to patient enrollment are accrued as patients progress through the clinical trial, including amortization of any first-patient prepayments. This amortization generally matches when the related services are rendered, however, these cost estimates may or may not match the actual costs incurred by the CROs or clinical trial sites, and if we have incomplete or inaccurate information, our clinical trial accruals may not be accurate. The difference between accrued expenses based on our estimates and actual expenses have not been significant to date.

Stock-Based Compensation

We grant options to purchase common stock to our employees, directors and consultants under our equity incentive plans. Under our employee stock purchase plan, eligible employees can also purchase shares of our common stock at 85% of the lower of the fair market value of our common stock at the beginning of a 12-month offering period or at the end of one of the two related six-month purchase periods.

We value these share-based awards using the Black-Scholes option valuation model, or the Black-Scholes Model. The determination of fair value of share-based payment awards on the date of grant using the Black-Scholes Model is affected by our stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors and related estimated forfeitures, which require significant analysis and judgment to develop.

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Overview of Revenues

We have not generated any revenue from the sale of commercial products, and do not anticipate product sales until at least 2016, if at all. Over the past three years, we have generated revenue primarily through the Royalty Agreement with RPI, and the license and collaboration agreement with Biogen Idec. We cannot predict whether we will receive any additional event-based payments or royalties from these agreements, as amended, in the foreseeable future, or at all.

Overview of Operating Expenses

Research and development expense. Most of our operating expenses to date have been for research and development activities, and include costs incurred:

· in the preparation and execution of clinical trials, including those for vosaroxin;

· in the discovery and development of novel small molecule therapeutics;

· in the development and use of in-house research, preclinical study and development capabilities;

· in connection with in-licensing activities; and

· in the conduct of activities related to strategic collaborations.

We are currently focused on the development of vosaroxin for the treatment of AML. Based on results of translational research, our own and investigator-sponsored trials, regulatory and competitive concerns and our overall financial resources, we anticipate that we will make determinations as to which indications to pursue and patient populations to treat in the future, and how much funding to direct to each indication, which will affect our research and development expense. If we proceed to commercialization following the  approval of either an MAA filing with the EMA or a New Drug Application, or NDA, filing with the FDA, research and development costs may increase in the future.

As of December 31, 2014, we had incurred $180.0 million of expenses in the development of vosaroxin since it was licensed from Sumitomo Dainippon Pharma Co., Ltd., or Sumitomo, in October 2003. We may continue to incur significant expenses related to the development of vosaroxin in future years. Due to the above uncertainties and other risks inherent in the development process, we are unable to estimate the costs we will incur in the vosaroxin development program in the future.

If we engage a development or commercialization partner for our vosaroxin program, or if, in the future, we acquire additional product candidates, our research and development expenses could be significantly affected. We cannot predict whether future licensing or collaborative arrangements will be secured, if at all, and to what degree such arrangements would affect our development plans and capital requirements.

In 2014 we incurred a total of $3.7 million of development expenses associated with advancing the SNS-062 and PDK1 inhibitor programs, and anticipate continuing expenditures on these programs in 2015 and beyond. Additionally, under the Millennium Agreement, we have the right to participate in co-development and co-promotion activities for the related product candidates, including MLN2480, a pan-RAF inhibitor currently in the maximum tolerated dose cohort expansion stage of a Millennium Phase 1, multicenter dose escalation study. If we were to exercise our option on this or other product candidates, our research and development expense would increase significantly.

General and administrative expense. General and administrative expense consists primarily of personnel costs for the related employees, including non-cash stock-based compensation; professional service costs, including fees paid to outside legal advisors, marketing consultants and our independent registered public accounting firm; facilities expenses; and other administrative costs. If we proceed to commercialization in either Europe or the United States following our regulatory interactions with the EMA and FDA, we anticipate general and administrative expenses to increase in the future, including additional costs related to selling and marketing.

Results of Operations

Years Ended December 31, 2014 and 2013

Revenue. Total revenue was $5.7 million in 2014 as compared to $8.0 million in 2013, primarily due to deferred revenue recognized related to the Royalty Agreement with RPI in each period. We expect deferred revenue recognized under this arrangement to be lower in 2015 than in 2014 due to the change in the end date of the estimated performance period through which the balance of deferred revenue will be amortized from June 30, 2015 to September 30, 2016.

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Research and development expense. Research and development expense was $27.7 million in 2014 as compared to $28.9 million in 2013, primarily relating to the vosaroxin development program in each year. The decrease of $1.2 million in 2014 was primarily due to a decrease of $7.1 million in clinical trial expenses, partially offset by increases of $2.1 million in personnel costs (including an increase of $0.6 million in stock-based compensation expense), $1.8 million in other outside services and consulting costs, $1.6 million in drug manufacturing costs, and $0.4 million in other development costs.

General and administrative expense. General and administrative expense was $23.1 million in 2014 as compared to $10.8 million in 2013. The increase of $12.3 million in 2014 was primarily due to increases of $6.7 million in professional services costs and $5.5 million in personnel costs (including an increase of $1.7 million in stock-based compensation expense).

Interest expense. Interest expense was $1.7 million in 2014 as compared to $2.9 million in 2013. The decrease in 2014 was due to the reduced principal balance outstanding on notes payable to the Lenders under the Loan Agreement.

Other income (expense), net. Net other income was $3.8 million in 2014 as compared to $0.1 million in 2013. The 2014 amount was primarily comprised of a net non-cash credit for the revaluation of warrants issued in the 2010 Offering.

Years Ended December 31, 2013 and 2012

Revenue. Total revenue was $8.0 million in 2013 as compared to $3.8 million in 2012. Revenue in 2013 was due to deferred revenue recognized related to the Royalty Agreement with RPI. Revenue in 2012 was comprised of $1.5 million received from Biogen Idec for the advancement of pre-clinical work under the Biogen Idec 1st ARCA and $2.3 million of deferred revenue recognized related to the Royalty Agreement with RPI.

Research and development expense. Research and development expense was $28.9 million in 2013 as compared to $29.2 million in 2012, substantially all relating to the vosaroxin development program in each year. The decrease of $0.3 million in 2013 was primarily due to decreases of $1.1 million in drug manufacturing costs and $1.3 million in other outside services and consulting costs, partially offset by increases of $1.2 million in personnel costs and $0.9 million in clinical trial expenses.

General and administrative expense. General and administrative expense was $10.8 million in 2013 as compared to $9.2 million in 2012. The increase of $1.6 million in 2013 was primarily due to increases of $1.0 million in professional services costs and $0.7 million in personnel costs.

Interest expense. Interest expense was $2.9 million in 2013 as compared to $1.9 million in 2012. The increase in 2013 was due to the additional interest expense related to the draw-down of the $15.0 million second tranche from the Lenders under the Loan Agreement in September 2012.

Other income (expense), net. Net other income was $0.1 million in 2013 as compared to net other expense of $7.5 million in 2012. The 2012 amount was primarily comprised of a net non-cash charge for the revaluation of warrants issued in the 2010 Offering.

Income Taxes

Deferred tax assets or liabilities may arise from differences between the tax basis of assets or liabilities and their basis for financial reporting. Deferred tax assets or liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which temporary differences are expected to be recovered or settled. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. Our policy is to recognize interest charges and penalties in other income (expense), net in the statements of operations and comprehensive loss.

Since inception, we have incurred operating losses and, accordingly, have not recorded a provision for income taxes for any of the periods presented. As of December 31, 2014, we had net operating loss carry-forwards for federal and state income tax purposes of $364.5 million and $235.8 million, respectively. We also had federal and state research and development tax credit carry-forwards of $8.1 million and $7.2 million, respectively. If not utilized, the federal net operating loss and tax credit carry-forwards will expire at various dates beginning in 2018 and the state net operating loss will begin to expire in 2015. The state research and development tax credit carry-forwards do not expire. Utilization of these net operating loss and tax credits carry-forwards may be subject to a substantial annual limitation due to ownership change rules under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code. The limitations are applicable if an “ownership change,” as defined in the Code, is deemed to have occurred or occurs in the future. The annual limitation may result in the expiration of net operating loss and credit carry-forwards before they can be utilized.

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Liquidity and Capital Resources

Sources of Liquidity

Since our inception, we have funded our operations primarily through the issuance of common and preferred stock and other equity instruments, debt financings, the receipt of funds from our collaboration partners, the sale of revenue participation rights, and research grants.

Our cash, cash equivalents and marketable securities totaled $43.0 million as of December 31, 2014, as compared to $39.3 million as of December 31, 2013. The increase of $3.7 million was primarily due to net proceeds of $40.0 million from the underwritten offering and $14.3 million from sales of our common stock through the Sales Agreement with Cantor, both as described below, and $2.0 million from the exercise of warrants, stock options and stock purchase rights, partially offset by $43.2 million of net cash used in operating activities and $9.4 million of principal payments against notes payable.

In March 2014, we completed an underwritten offering of 4,650,000 shares of common stock, each with two accompanying warrants to purchase one share of our common stock, at exercise prices of $8.50 (Series A) and $12.00 (Series B) per share, respectively. The purchase price for each share of common stock and two accompanying warrants was $9.25. Gross proceeds from the sale were $43.0 million and net proceeds were $40.0 million, after deducting the underwriting discount and offering expenses. The warrants are only exercisable on a gross exercise basis. The Series A warrants expired on December 4, 2014. The Series B warrants will expire on or before the later of 30 days following the PDUFA date of the VALOR trial, if any, and September 4, 2015, but in no event later than March 4, 2016.

During 2014, we sold an aggregate of 5,113,876 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.88 per share for proceeds of $14.7 million and net proceeds of $14.3 million, after deducting Cantor’s commission. As of December 31, 2014, $6.8 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the agreement.

Cash Flows

Net cash used in operating activities was $43.2 million in 2014, as compared to $37.4 million in 2013 and $10.6 million in 2012. Net cash used in 2014 resulted primarily from the net loss of $43.0 million and changes in operating assets and liabilities of $2.9 million (including $5.7 million related to recognition of deferred revenue under the Royalty Agreement), partially offset by net adjustments for non-cash items of $2.7 million (including expenses of $6.2 million for stock-based compensation and a $3.9 million credit for the revaluation of warrants issued in the 2010 Offering). Net cash used in 2013 resulted primarily from the net loss of $34.6 million and changes in operating assets and liabilities of $7.1 million (including $8.0 million related to recognition of deferred revenue under the Royalty Agreement), partially offset by net adjustments for non-cash items of $4.3 million (including expenses of $3.9 million for stock-based compensation). Net cash used in 2012 resulted primarily from the net loss of $44.0 million, partially offset by net adjustments for non-cash items of $10.6 million (including a charge of $7.5 million for the revaluation of warrants issued in the 2010 Offering and $2.7 million of stock-based compensation), and changes in operating assets and liabilities of $22.7 million (including a net increase in deferred revenue of $19.6 million related to the receipt of the $25.0 million payment from RPI, and an increase of $3.1 million in accrued clinical expenses related to the VALOR trial).

Net cash provided by investing activities was $3.3 million in 2014, as compared to $32.2 million provided by investing activities in 2013 and $21.4 million used in investing activities in 2012. Net cash provided in 2014 and 2013 consisted primarily of proceeds from maturities of marketable securities, partially offset by purchases of marketable securities. Net cash used in 2012 consisted primarily of purchases of marketable securities, partially offset by proceeds from maturities of marketable securities.

Net cash provided by financing activities was $46.9 million in 2014, as compared to $5.4 million in 2013 and $37.6 million in 2012. Net cash provided in 2014 resulted primarily from net proceeds of $40.0 million from the underwritten offering, $14.3 million from sales of our common stock through Cantor and $2.0 million from the exercise of warrants, stock options and stock purchase rights, partially offset by $9.4 million of principal payments against notes payable. Net cash provided in 2013 resulted primarily from net proceeds of $12.0 million from sales of our common stock through Cantor and $0.6 million from the exercise of warrants, stock options and stock purchase rights, partially offset by $7.2 million of principal payments against notes payable. Net cash provided in 2012 included net proceeds from the draw-down of the second tranche loan of $15.0 million from the Lenders, $17.6 million from sales of our common stock through Cantor, $3.1 million of the $25.0 million payment allocated to the fair value of warrants issued to RPI, and $1.9 million from the exercise of warrants, stock options and stock purchase rights.

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Operating Cash Requirements

We expect to continue to incur substantial operating losses in the future. We will not receive any product revenue until a product candidate has been approved by the FDA, EMA, or similar regulatory agencies in other countries, and has been successfully commercialized, if at all. We will need to raise substantial additional funding to complete the development and potential commercialization of vosaroxin. Additionally, we may evaluate in-licensing and acquisition opportunities to gain access to new drugs or drug targets that would fit with our strategy. Any such transaction would likely increase our funding needs in the future.

Our future funding requirements will depend on many factors, including but not limited to:

· the rate of progress and cost of our clinical trials;

· the need for additional or expanded clinical trials;

· the timing, economic and other terms of any licensing, collaboration or other similar arrangement into which we may enter;

· the costs and timing of seeking and obtaining FDA, EMA, or other regulatory approvals;

· the extent of our other development activities, including our in-license agreements;

· the costs associated with building or accessing commercialization and additional manufacturing capabilities and supplies;

· the costs of acquiring or investing in businesses, product candidates and technologies, if any;

· the costs of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights;

· the effect of competing technological and market developments; and

· the costs, if any, of supporting our arrangements with Biogen Idec and Millennium.

We believe that we currently have the resources to fund our operations through the first quarter of 2016. We will need to raise substantial additional capital to complete the development and potential commercialization of vosaroxin. Until we can generate a sufficient amount of licensing or collaboration or product revenue to finance our cash requirements, which we may never do, we expect to finance our future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to vosaroxin, or a combination of the above.

Our failure to raise significant additional capital in the future would force us to delay or reduce the scope of our vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease our operations. Any one of the foregoing would have a material adverse effect on our business, financial condition and results of operations.

Contractual Obligations

The following table summarizes our long-term contractual obligations as of December 31, 2014 (in thousands):

	Payments Due by Period
			Less Than						After
	Total		1 Year		1-3 Years		3-5 Years		5 Years
Debt obligations(1)	$	9,752	$	9,752	$	—	$	—	$	—
Operating lease obligations(2)	$	247	$	247	$	—	$	—	$	—

(1) Includes interest and final payment of $937,500 (3.75%) of the aggregate amount drawn. Upon the occurrence of an event of default, as defined in the Loan Agreement, and following any applicable cure periods, a default interest rate of an additional 5% may be applied to the outstanding loan balances, and the Lenders may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Loan Agreement. On February 27, 2015, the Loan Agreement was modified such that repayments are interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. In addition, the final payment will be increased from $937,500 (3.75%) to $1,162,500 (4.65%) of the aggregate amount drawn, and will become due on the new maturity date, or such earlier date specified in the Loan Agreement. If we repay all or a portion of the loan prior to February 29, 2016 as part of a refinancing with another lender, a prepayment fee equal to 2% of the then outstanding principal balance will be due to the Lenders.

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(2) Operating lease obligations relate solely to the leasing of  office space in a building at 395 Oyster Point Boulevard in South San Francisco, California, which is currently our corporate headquarters. In January 2014, a lease for 15,378 square feet was entered into with an expiration date of April 30, 2015. In June 2014, the lease was amended to extend the expiration date to June 30, 2015, and to add 6,105 square feet of additional office space within the same building. In January 2015, the lease was further amended to extend the expiration date to December 31, 2015.

The above amounts exclude potential payments under:

· our 2003 license agreement with Sumitomo, pursuant to which we are required to make certain milestone payments in the event we file new drug applications in the United States, Europe or Japan, and if we receive regulatory approvals in any of these regions, for cancer-related indications. If vosaroxin is approved for a non-cancer indication, an additional milestone payment becomes payable to Sumitomo. We are also required to make royalty payments to Sumitomo in the event that vosaroxin is commercialized.

· our Royalty Agreement with RPI, pursuant to which we are required to make certain revenue participation payments in the event that vosaroxin is commercialized.

· our December 2013 second amended and restated collaboration agreement with Biogen Idec and our January 2014 amended license agreement with Millennium, pursuant to which we are required to make certain milestone and royalty payments.

We also have agreements with CROs, clinical sites and other third party contractors for the conduct of our clinical trials. We generally make payments to these entities based upon the activities they perform related to the particular clinical trial. There are generally no penalty clauses for cancellation of these agreements if notice is duly given and payment is made for work performed by the third party under the related agreement.

Off-Balance Sheet Arrangements

Since our inception, we have not had any off-balance sheet arrangements or relationships with unconsolidated entities or financial partnerships, such as entities often referred to as structured finance or variable interest entities, which are typically established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes.

ITEM 7A. QUALITATIVE AND QUANTITATIVE DISCLOSURES ABOUT MARKET RISK

Interest Rate and Market Risk

As of December 31, 2014 and 2013, we had $43.0 million and $39.3 million, respectively, in cash, cash equivalents and marketable securities. The securities in our investment portfolio are not leveraged and are classified as available-for-sale, which, due to their short-term nature, are subject to minimal interest rate risk. We currently do not hedge our interest rate risk exposure. Because of the short-term maturities of our investments, we do not believe that a change in market rates would have a significant impact on the value of our investment portfolio.

The primary objective of our investment activities is to preserve principal while at the same time maximizing the income we receive from our investments without significantly increasing risk. To achieve this objective, we maintain our portfolio of cash equivalents and short-term and long-term investments in a variety of securities, including money market funds and U.S. and European government obligations and corporate debt securities. These securities are classified as available for sale and consequently are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of accumulated other comprehensive (loss) income. Substantially all investments mature within approximately one year from the date of purchase. Our holdings of the securities of any one issuer, except obligations of the U.S. Treasury or U.S. Treasury guaranteed securities, do not exceed 10% of the portfolio. If interest rates rise, the market value of our investments may decline, which could result in a realized loss if we are forced to sell an investment before its scheduled maturity. We do not utilize derivative financial instruments to manage our interest rate risks.

46

The tables below present the original principal amounts and weighted-average interest rates by year of maturity for our investment portfolio as of December 31 of each year, by effective maturity (in thousands, except percentages):

	Expected Maturity						Total
	0-3			Over 3			Fair Value as of December 31,
	months			months			2014
Available-for-sale securities	$	17,260		$	13,067		$	30,327
Average interest rate		0.2	%		0.3	%

	Expected Maturity						Total
	0-3			Over 3			Fair Value as of December 31,
	months			months			2013
Available-for-sale securities	$	20,387		$	10,368		$	30,755
Average interest rate		0.2	%		0.3	%

Foreign Currency Exchange Rate Risk

We consider our direct exposure to foreign exchange rate fluctuations to be minimal. Invoices for certain services provided to us are denominated in foreign currencies, including the euro and British pound, among others. Therefore, we are exposed to adverse movements in the related foreign currency exchange rates. To manage this risk, we may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments allowed by our investment policy. We do not make these purchases for trading or speculative purposes, and there is no guarantee that the related gains and losses will substantially offset each other. As of December 31, 2014 and 2013, we held investments denominated in Euros with an aggregate fair value of nil and $2.6 million, respectively. The balances are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are recorded in other income (expense), net in the statements of operations and comprehensive loss.

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ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

Index to Consolidated Financial Statements

	Page
Report of Independent Registered Public Accounting Firm	49
Consolidated Balance Sheets	50
Consolidated Statements of Operations and Comprehensive Loss	51
Consolidated Statements of Stockholders’ Equity (Deficit)	52
Consolidated Statements of Cash Flows	53
Notes to Consolidated Financial Statements	54

48

Report of Independent Registered Public Accounting Firm

The Board of Directors and Stockholders of Sunesis Pharmaceuticals, Inc.

We have audited the accompanying consolidated balance sheets of Sunesis Pharmaceuticals, Inc. as of December 31, 2014 and 2013, and the related consolidated statements of operations and comprehensive loss, stockholders’ equity (deficit), and cash flows for each of the three years in the period ended December 31, 2014. These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the consolidated financial position of Sunesis Pharmaceuticals, Inc. at December 31, 2014 and 2013, and the consolidated results of its operations and its cash flows for each of the three years in the period ended December 31, 2014, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), Sunesis Pharmaceuticals, Inc.’s internal control over financial reporting as of December 31, 2014, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) and our report dated March 12, 2015 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Redwood City, California

March 12, 2015

49

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED BALANCE SHEETS

(In thousands, except per share amounts)

	December 31,
	2014			2013
ASSETS
Current assets:
Cash and cash equivalents	$	22,186		$	15,121
Marketable securities		20,795			24,172
Prepaids and other current assets		1,223			1,199
Total current assets		44,204			40,492
Property and equipment, net		42			23
Deposits and other assets		—			10
Total assets	$	44,246		$	40,525
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Current liabilities:
Accounts payable	$	3,177		$	953
Accrued clinical expense		3,112			4,750
Accrued compensation		2,287			1,719
Other accrued liabilities		3,087			1,645
Current portion of deferred revenue		3,418			7,956
Current portion of notes payable		9,257			9,018
Warrant liability		3,543			7,931
Total current liabilities		27,881			33,972
Non-current portion of deferred revenue		2,563			3,712
Non-current portion of notes payable		—			9,025
Commitments and contingencies (Note 9)
Stockholders’ equity (deficit):
Common stock, $0.0001 par value; 400,000 shares authorized as of December 31, 2014; 66,102 and 54,344 shares issued and outstanding as of December 31, 2014 and 2013, respectively		7			5
Additional paid-in capital		536,499			473,509
Accumulated other comprehensive loss		(7	)		(3	)
Accumulated deficit		(522,697	)		(479,695	)
Total stockholders’ equity (deficit)		13,802			(6,184	)
Total liabilities and stockholders’ equity (deficit)	$	44,246		$	40,525

See accompanying notes to consolidated financial statements.

50

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(In thousands, except per share amounts)

	Year Ended December 31,
	2014			2013			2012
Revenue:
License and other revenue	$	5,734		$	7,956		$	3,754
Total revenues		5,734			7,956			3,754
Operating expenses:
Research and development		27,665			28,891			29,185
General and administrative		23,112			10,838			9,175
Total operating expenses		50,777			39,729			38,360
Loss from operations		(45,043	)		(31,773	)		(34,606	)
Interest expense		(1,719	)		(2,917	)		(1,855	)
Other income (expense), net		3,760			92			(7,490	)
Net loss		(43,002	)		(34,598	)		(43,951	)
Unrealized (loss) gain on available-for-sale securities		(4	)		(41	)		19
Comprehensive loss		(43,006	)	$	(34,639	)	$	(43,932	)
Basic and diluted loss per common share:
Net loss:
Basic	$	(43,002	)	$	(34,598	)	$	(43,951	)
Diluted	$	(46,894	)	$	(34,598	)	$	(43,951	)
Shares used in computing net loss per common share:
Basic		60,057			52,249			48,146
Diluted		61,510			52,249			48,146
Net loss per common share:
Basic	$	(0.72	)	$	(0.66	)	$	(0.91	)
Diluted	$	(0.76	)	$	(0.66	)	$	(0.91	)

See accompanying notes to consolidated financial statements.

51

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT)  

(In thousands)

							Accumulated						Total
							Other						Stock
					Additional		Comprehensive						holders’
	Common Stock				Paid-In		(Loss)			Accumulated			(Deficit)
	Shares		Amount		Capital		Income			Deficit			Equity
Balance as of December 31, 2011		46,774	$	5	$	429,142	$	19		$	(401,146	)	$	28,020
Issuance of $18,124 of common stock through controlled equity offering facilities, net of issuance costs of $504		3,714		—		17,620		—			—			17,620
Issuance of common stock pursuant to warrant exercises		801		—		3,130		—			—			3,130
Issuance of common stock pursuant to stock option exercises		146		—		330		—			—			330
Issuance of common stock under employee stock purchase plans		84		—		172		—			—			172
Issuance of common stock to employees		46		—		—		—			—			—
Issuance of warrants to purchase common stock		—		—		3,893		—			—			3,893
Stock-based compensation expenses—employees		—		—		2,402		—			—			2,402
Stock-based compensation expenses—non-employees		—		—		322		—			—			322
Net loss		—		—		—		—			(43,951	)		(43,951	)
Unrealized gain on available-for-sale securities		—		—		—		19			—			19
Balance as of December 31, 2012		51,565		5		457,011		38			(445,097	)		11,957
Issuance of $12,357 of common stock through controlled equity offering facilities, net of issuance costs of $371		2,535		—		11,986		—			—			11,986
Issuance of common stock pursuant to warrant exercises		18		—		88		—			—			88
Issuance of common stock pursuant to stock option exercises		104		—		230		—			—			230
Issuance of common stock under employee stock purchase plans		97		—		309		—			—			309
Issuance of common stock to employees		25		—		—		—			—			—
Stock-based compensation expenses—employees		—		—		3,581		—			—			3,581
Stock-based compensation expenses—non-employees		—		—		304		—			—			304
Net loss		—		—		—		—			(34,598	)		(34,598	)
Unrealized loss on available-for-sale securities		—		—		—		(41	)		—			(41	)
Balance as of December 31, 2013		54,344		5		473,509		(3	)		(479,695	)		(6,184	)
Issuance of $43,013 of common stock and warrants in underwritten offering, net of issuance costs of $2,989		4,650		1		40,023		—			—			40,024
Issuance of $14,734 of common stock through controlled equity offering facilities, net of issuance costs of $442		5,114		1		14,291		—			—			14,292
Issuance of common stock pursuant to warrant exercises		1,323		—		949		—			—			949
Issuance of common stock pursuant to stock option exercises		566		—		1,226		—			—			1,226
Issuance of common stock under employee stock purchase plans		99		—		282		—			—			282
Issuance of common stock to employees		6		—		—		—			—			—
Stock-based compensation expenses—employees		—		—		5,882		—			—			5,882
Stock-based compensation expenses—non-employees		—		—		337		—			—			337
Net loss		—		—		—		—			(43,002	)		(43,002	)
Unrealized loss on available-for-sale securities		—		—		—		(4	)		—			(4	)
Balance as of December 31, 2014		66,102	$	7	$	536,499	$	(7	)	$	(522,697	)	$	13,802

See accompanying notes to consolidated financial statements.

52

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

	Year Ended December 31,
	2014			2013			2012
Cash flows from operating activities
Net loss	$	(43,002	)	$	(34,598	)	$	(43,951	)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense		6,219			3,885			2,724
Depreciation and amortization		29			20			31
Amortization of debt discount and debt issuance costs		367			621			400
(Decrease) increase in fair value of warrant liability		(3,892	)		(96	)		7,509
Foreign exchange gain on marketable securities		—			(142	)		(82	)
Gain on sale of property and equipment		—			—			(11	)
Changes in operating assets and liabilities:
Prepaids and other assets		(43	)		489			(98	)
Accounts payable		2,224			875			(580	)
Accrued clinical expense		(1,638	)		(699	)		3,079
Accrued compensation		568			254			191
Other accrued liabilities		1,674			(76	)		522
Deferred revenue		(5,687	)		(7,956	)		19,624
Net cash used in operating activities		(43,181	)		(37,423	)		(10,642	)
Cash flows from investing activities
Purchases of property and equipment		(48	)		—			—
Proceeds from sale of property and equipment		—			—			11
Purchases of marketable securities		(42,463	)		(26,894	)		(67,608	)
Proceeds from maturities of marketable securities		45,836			59,110			46,226
Net cash provided by (used in) investing activities		3,325			32,216			(21,371	)
Cash flows from financing activities
Proceeds from notes payable, net		—			—			14,982
Principal payments on notes payable		(9,356	)		(7,182	)		—
Proceeds from issuance of common stock and warrants in underwritten    offering, net		40,024			—			—
Proceeds from issuance of common stock through controlled equity    offering facilities, net		14,292			11,986			17,620
Fair value of warrants issued in connection with royalty agreement		—			—			3,122
Proceeds from exercise of warrants, stock options and stock purchase    rights		1,961			584			1,918
Net cash provided by financing activities		46,921			5,388			37,642
Net increase (decrease) in cash and cash equivalents		7,065			181			5,629
Cash and cash equivalents at beginning of period		15,121			14,940			9,311
Cash and cash equivalents at end of period	$	22,186		$	15,121		$	14,940
Supplemental disclosure of cash flow information
Interest paid	$	1,221		$	2,006		$	1,165
Supplemental disclosure of non-cash activities
Transfer of fair value of exercised warrants to additional paid-in capital	$	496		$	43		$	1,715
Fair value of warrants issued in connection with notes payable	$	—		$	—		$	770
Cashless exercise of warrants	$	9,337		$	—		$	402

See accompanying notes to consolidated financial statements.

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SUNESIS PHARMACEUTICALS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1. Company Overview

Description of Business

Sunesis Pharmaceuticals, Inc. (the “Company” or “Sunesis”) was incorporated in the state of Delaware on February 10, 1998, and its facilities are located in South San Francisco, California. Sunesis is a biopharmaceutical company focused on the development and commercialization of new oncology therapeutics for the treatment of solid and hematologic cancers. The Company’s primary activities since incorporation have been conducting research and development internally and through corporate collaborators, in-licensing and out-licensing pharmaceutical compounds and technology, conducting clinical trials and raising capital.

In October 2014, the Company announced the results of a Phase 3, multi-national, randomized, double-blind, placebo-controlled, clinical trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory acute myeloid leukemia (the “VALOR trial”). The trial did not meet its primary endpoint of demonstrating a statistically significant improvement in overall survival, but based upon the favorable results of other predefined analyses of the data, Sunesis plans to meet with European regulatory authorities in preparation for the filing of a marketing authorization application (“MAA”) with the European Medicines Agency (“EMA”) in the second half of 2015. The Company is also currently engaged in discussions with the U.S. Food and Drug Administration (“FDA”) to determine a potential regulatory path forward in the United States.

Significant Risks and Uncertainties

The Company has incurred significant losses and negative cash flows from operations since its inception, and as of December 31, 2014, had cash, cash equivalents and marketable securities totaling $43.0 million and an accumulated deficit of $522.7 million.

The Company will need to raise substantial additional capital to pursue a regulatory strategy for the potential commercialization of QINPREZO^TM(vosaroxin), its product candidate for the potential treatment of acute myeloid leukemia, and to continue the development of vosaroxin and the Company’s other programs. The Company expects to finance its future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to vosaroxin and its other development programs, or a combination of the above. However, the Company does not know whether additional funding will be available on acceptable terms, or at all. If the Company is unable to raise required funding on acceptable terms or at all, it will need to reduce operating expenses, enter into a collaboration or other similar arrangement with respect to development and/or commercialization rights to vosaroxin, outlicense intellectual property rights to vosaroxin or our other development programs, sell unsecured assets, or a combination of the above, or be forced to delay or reduce the scope of our vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease our operations.

Concentrations of Credit Risk

In accordance with its investment policy, the Company invests cash that is not currently being used for operational purposes. The policy allows for the purchase of low risk debt securities issued by: (a) the United States and certain European governments and government agencies, and (b) highly rated banks and corporations, denominated in U.S. dollars, Euros or British pounds, subject to certain concentration limits. The policy limits maturities of securities purchased to no longer than 24 months and the weighted average maturity of the portfolio to 12 months. Management believes these guidelines ensure both the safety and liquidity of any investment portfolio the Company may hold.

Financial instruments that potentially subject the Company to concentrations of credit risk generally consist of cash, cash equivalents and marketable securities. The Company is exposed to credit risk in the event of default by the institutions holding its cash, cash equivalents and any marketable securities to the extent of the amounts recorded in the balance sheets.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”).

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Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), that will supersede most existing revenue recognition guidance under US GAAP. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. Entities electing the full retrospective adoption will apply the standard to each period presented in the financial statements. This means that entities will have to apply the new guidance as if it had been in effect since the inception of all its contracts with customers presented in the financial statements. Entities that elect the modified retrospective approach will apply the guidance retrospectively only to the most current period presented in the financial statements. This means that entities will have to recognize the cumulative effect of initially applying the new standard as an adjustment to the opening balance of retained earnings at the date of initial application. The new revenue standard will be applied to contracts that are in progress at the date of initial application. The standard will be effective for annual and interim periods beginning after December 15, 2016. The Company has yet to evaluate which adoption method it plans to use or the potential effect of the new standard on its consolidated financial statements.

In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”), which will require a reporting entity to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the reporting entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures. The standard will be effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has yet to evaluate the potential effect of the new standard on its consolidated financial statements.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Sunesis Europe Limited, a United Kingdom corporation, and Sunesis Pharmaceuticals (Bermuda) Ltd., a Bermuda corporation, as well as a Bermuda limited partnership, Sunesis Pharmaceuticals International LP. All intercompany balances and transactions have been eliminated in consolidation.

Segment Reporting

Management has determined that the Company operates as a single reportable segment.

Significant Estimates and Judgments

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes thereto. Actual results could differ materially from these estimates. Estimates, assumptions and judgments made by management include those related to the valuation of equity and related instruments, revenue recognition, stock-based compensation and clinical trial accounting.

Cash Equivalents and Marketable Securities

The Company considers all highly liquid securities with original maturities of three months or less from the date of purchase to be cash equivalents, which generally consist of money market funds and corporate debt securities. Marketable securities consist of securities with original maturities of greater than three months, which may include U.S. and European government obligations and corporate debt securities.

Management determines the appropriate classification of securities at the time of purchase. The Company generally classifies its entire investment portfolio as available-for-sale. The Company views its available-for-sale portfolio as available for use in current operations. Accordingly, the Company classifies all investments as short-term, even though the stated maturity may be more than one year from the current balance sheet date. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported in accumulated other comprehensive income (loss), which is a separate component of stockholders’ equity (deficit).

The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in other income (expense), net in the statements of operations and comprehensive loss. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities, if any, are also recorded to other income (expense), net. The cost of securities sold is based on the specific-identification method.

55

Invoices for certain services provided to the Company are denominated in foreign currencies. To manage the risk of future movements in foreign exchange rates that would affect such amounts, the Company may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments defined in the Company’s investment policy. There is no guarantee that the related gains and losses will substantially offset each other, and the Company may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter. To date, the Company has purchased Euros and Euro-denominated obligations of foreign governments and corporate debt. As of December 31, 2014 and December 31, 2013, the Company held investments denominated in Euros with an aggregate fair value of $0 and $2.6 million, respectively. Any cash, cash equivalent and short-term investment balances denominated in foreign currencies are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are both recorded in other income (expense), net in the statements of operations and comprehensive loss.

Fair Value Measurements

The Company measures cash equivalents, marketable securities and warrant liabilities at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable GAAP:

Level 1 -	quoted prices (unadjusted) in active markets for identical assets and liabilities that can be accessed at the measurement date
Level 2 -	inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly
Level 3 -	unobservable inputs

The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets.

The fair value of the Company’s liability for warrants issued in connection with an underwritten offering completed in October 2010 (the “2010 Offering”) is determined using the Black-Scholes model, which requires inputs such as the expected term of the warrants, share price volatility, expected dividend yield and risk-free interest rate. As some of these inputs are unobservable, and require significant analysis and judgment to measure, these variables are classified as Level 3.

The carrying amounts of the Company’s financial instruments, including cash, prepayments, accounts payable, accrued liabilities, deferred revenue and notes payable approximated their fair value as of December 31, 2014 and December 31, 2013.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is determined using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the term of the lease.

Accounting for Royalty Agreement

The payment of $25.0 million by RPI under the Royalty Agreement (see Note 6) is non-refundable, and no revenue participation right payments will be made unless vosaroxin is commercialized. Accordingly, the payment received from RPI is being accounted for as a payment for the Company to use commercially reasonable efforts to commercialize vosaroxin. Therefore, the amount is to be deferred and recognized as revenue over the projected performance period under the agreement. The payment, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period. The fair value of the warrants was recorded to additional paid-in capital.

Accounting for Notes Payable

The accounting for certain fees and expenses related to the Loan Agreement (see Note 8) is as follows. The facility fee is being accounted for as a debt discount and classified within notes payable on the Company’s balance sheet. The fair value of the warrants issued in connection with the Loan Agreement have been recorded as a debt discount within notes payable and an increase to additional paid-in capital on the Company’s balance sheet. The debt discount is being amortized as interest expense over the term of the loan using the effective interest method. The final payment is being accreted as interest expense over the term of the loans using the effective interest method. The legal fees are being accounted for as deferred debt issuance costs within assets on the Company’s balance sheet and are being amortized as other income (expense), net over the term of the loans using the effective interest method.

56

Accounting for Equity Financing

In October 2010, the Company completed the 2010 Offering (see Note 10), in which the Company sold its common stock and warrants to purchase its common stock for aggregate gross proceeds of $15.5 million. Due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements, the warrants are being accounted for as a derivative liability as opposed to permanent equity. Outstanding warrants under this arrangement are revalued to their fair value each period end, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss.

Revenue Recognition

Revenue arrangements with multiple deliverables are accounted for in accordance with the Financial Accounting Standards Board Accounting Standards Codification, Subtopic 605-25, Multiple-Element Arrangements (“ASC 605-25”). Under ASC 605-25, revenue arrangements with multiple deliverables are divided into separate units of accounting based on whether certain criteria are met, including whether the delivered item has stand-alone value to the customer. Consideration is allocated among the separate units of accounting based on their respective fair value, and the applicable revenue recognition is applied to each of the separate units.

Non-refundable fees where the Company has no continuing performance obligations are recognized as revenues when collection is reasonably assured. In situations where continuing performance obligations exist, non-refundable fees are deferred and recognized ratably over the projected performance period.

Milestone payments from license or collaboration agreements which are substantive and at risk at the time the agreement is executed are recognized upon completion of the applicable milestone event. Royalty revenues, if any, will be recognized based on reported product sales by third-party licensees. Research funding from any future agreement will be recognized as the related research services are performed.

Research and Development

Research and development expense consists primarily of: (a) clinical trial costs, which include payments for work performed by contract research organizations (“CROs”), clinical trial sites, labs and other clinical service providers, and for drug packaging, storage and distribution; (b) drug manufacturing costs, which include costs for producing drug substance and drug product, and for stability and other testing; (c) personnel costs for related permanent and temporary employees; (d) other outside services and consulting costs; and (e) payments under license agreements. All research and development costs are expensed as they are incurred.

Clinical Trial Accounting

The Company records accruals for estimated clinical trial costs, which include payments for work performed by CROs and participating clinical trial sites. These costs are generally a significant component of research and development expense. Costs incurred for setting up clinical trial sites for participation in trials are generally non-refundable, and are expensed as incurred, with any refundable advances related to enrollment of the first patient recorded as prepayments and assessed for recoverability on a quarterly basis. Costs related to patient enrollment are accrued as patients progress through the clinical trial, including amortization of any first-patient prepayments. This amortization generally matches when the related services are rendered, however, these cost estimates may or may not match the actual costs incurred by the CROs or clinical trial sites, and if the Company has incomplete or inaccurate information, the clinical trial accruals may not be accurate. The difference between accrued expenses based on the Company’s estimates and actual expenses have not been significant to date.

Stock-Based Compensation

The Company grants options to purchase common stock to its employees, directors and consultants under its stock option plans. Under the Company’s Employee Stock Purchase Plan, eligible employees can also purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock at the beginning of a 12-month offering period or at the end of one of the two related six-month purchase periods.

The Company values these share-based awards using the Black-Scholes option valuation model (the “Black-Scholes model”). The determination of fair value of share-based payment awards on the date of grant using the Black-Scholes model is affected by the Company’s stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors and related estimated forfeitures.

57

Foreign Currency

Transactions that are denominated in a foreign currency are translated into U.S. dollars at the current exchange rate on the transaction date. Any foreign currency-denominated monetary assets and liabilities are subsequently remeasured at current exchange rates as of each balance sheet date, with gains or losses on foreign exchange recognized in other income (expense), net in the statements of operations and comprehensive loss.

Income Taxes

The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the differences between the tax basis of assets and liabilities and their basis for financial reporting. Deferred tax assets or liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which temporary differences are expected to be recovered or settled. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company’s policy is to recognize interest charges and penalties in other income (expense), net in the statements of operations and comprehensive loss.

3. Loss per Common Share

Basic loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per common share is computed by dividing (a) net loss, less any anti-dilutive amounts recorded during the period for the change in the fair value of warrant liabilities, by (b) the weighted-average number of common shares outstanding for the period plus dilutive potential common shares as determined using the treasury stock method for options and warrants to purchase common stock.

The following table sets forth the computation of basic and diluted loss per common share for the periods presented (in thousands, except per share amounts):

	Year Ended December 31,
	2014			2013			2012
Numerator:
Net loss—basic	$	(43,002	)	$	(34,598	)	$	(43,951	)
Adjustment for change in fair value of warrant liability		(3,892	)		—			—
Net loss—diluted	$	(46,894	)	$	(34,598	)	$	(43,951	)
Denominator:
Weighted-average common shares outstanding—basic		60,057			52,249			48,146
Dilutive effect of warrants		1,453			—			—
Weighted-average common shares outstanding—diluted		61,510			52,249			48,146
Net loss per common share:
Basic	$	(0.72	)	$	(0.66	)	$	(0.91	)
Diluted	$	(0.76	)	$	(0.66	)	$	(0.91	)

The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted loss per common share because their inclusion would have had an anti-dilutive effect (in thousands):

	As of December 31,
	2014		2013		2012
Warrants to purchase shares of common stock		8,978		9,978		10,359
Options to purchase shares of common stock		10,584		7,611		6,288
Outstanding securities not included in calculations		19,562		17,589		16,647

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4. Financial Instruments

Financial Assets

The following tables summarize the estimated fair value of the Company’s financial assets measured on a recurring basis as of the dates indicated, which were comprised solely of available-for-sale marketable securities with remaining contractual maturities of one year or less (in thousands):

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2014	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	9,287		$	—	$	—		$	9,287
U.S. certificates of deposit	Level 1		6,360			—		—			6,360
U.S. corporate debt obligations	Level 2		11,789			—		(7	)		11,782
U.S. commercial paper	Level 2		2,898			—		—			2,898
Total available-for-sale securities			30,334			—		(7	)		30,327
Less amounts classified as cash equivalents			(9,532	)		—		—			(9,532	)
Amounts classified as marketable securities		$	20,802		$	—	$	(7	)	$	20,795

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2013	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	6,282		$	—	$	—		$	6,282
U.S. corporate debt obligations	Level 2		13,509			—		(4	)		13,505
U.S. commercial paper	Level 2		8,396			3		—			8,399
Foreign corporate debt obligations	Level 2		2,571			—		(2	)		2,569
Total available-for-sale securities			30,758			3		(6	)		30,755
Less amounts classified as cash equivalents			(6,583	)		—		—			(6,583	)
Amounts classified as marketable securities		$	24,175		$	3	$	(6	)	$	24,172

The following table summarizes the available-for-sale securities that were in an unrealized loss position as of December 31, 2014, each having been in such a position for less than 12 months, and none deemed to be other-than-temporarily impaired (in thousands):

	Gross
	Unrealized		Estimated Fair
December 31, 2014	Losses		Value
U.S. corporate debt obligations	$	7	$	11,782
Total available-for-sale securities in an unrealized loss    position	$	7	$	11,782

No significant facts or circumstances have arisen to indicate that there has been any deterioration in the creditworthiness of the issuers of these securities. The gross unrealized losses are not considered to be significant and have generally been for relatively short durations. The Company does not intend to sell these securities before maturity and it is not likely that they will need to be sold prior to the recovery of their amortized cost basis. There were no sales of available-for-sale debt securities in the years ended December 31, 2014, 2013 and 2012.

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Financial Liabilities

The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured on a recurring basis as of the dates indicated, which were comprised solely of a liability for warrants issued in connection with an underwritten equity offering completed in 2010 (see Note 10):

	December 31,			December 31,
	2014			2013
Inputs and assumptions:
Fair market value of Company’s common stock	$	2.55		$	4.74
Exercise price	$	2.52		$	2.52
Expected term (years)		0.8			1.8
Expected volatility		144.9	%		60.8	%
Risk-free interest rate		0.2	%		0.3	%
Expected dividend yield		0.0	%		0.0	%
Fair value:
Estimated fair value per warrant share	$	1.21		$	2.56
Shares underlying outstanding warrants classified as    liabilities (in thousands)		2,920			3,099
Total estimated fair value of outstanding warrants    (in thousands)	$	3,543		$	7,931

The warrants have been classified as a liability on the Company’s balance sheet due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements. At each balance sheet date, the estimated fair value of the outstanding warrants is determined using the Black-Scholes model and recorded to the balance sheet, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss, and the fair value of warrant exercises transferred to additional paid-in capital. During the year ended December 31, 2014, warrants to purchase 179,427 shares of common stock issued in connection with the 2010 Offering were exercised, resulting in cash proceeds to the Company of $452,000.

The Black-Scholes model requires Level 3 inputs such as the expected term of the warrants and share price volatility. These inputs are subjective and generally require significant analysis and judgment to develop. Any changes in these inputs could result in a significantly higher or lower fair value measurement.

The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities for the periods indicated (in thousands):

	Warrant
	Liability
Balance as of December 31, 2012	$	8,070
Change in fair value of warrant liability		(96	)
Exercise of warrants		(43	)
Balance as of December 31, 2013		7,931
Change in fair value of warrant liability		(3,892	)
Exercise of warrants		(496	)
Balance as of December 31, 2014	$	3,543

5. Other Accrued Liabilities

Other accrued liabilities as of December 31 were as follows (in thousands):

	2014		2013
Accrued outside services	$	2,656	$	1,249
Accrued professional services		355		263
Other accruals		76		133
Total other accrued liabilities	$	3,087	$	1,645

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6. Royalty Agreement

In March 2012, the Company entered into a Revenue Participation Agreement (the “Royalty Agreement”), with RPI Finance Trust (“RPI”), an entity related to Royalty Pharma. In September 2012, pursuant to the provisions of the Royalty Agreement, RPI made a $25.0 million cash payment to the Company. In conjunction with the Royalty Agreement, we issued two five-year warrants to RPI, each to purchase 1,000,000 shares of our common stock, at exercise prices of $3.48 and $4.64 per share, respectively. Both warrants were net exercised in 2014, resulting in an aggregate issuance of 777,107 shares of common stock. The payment of $25.0 million, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period.

Based on the results of the VALOR trial and the Company’s plans to meet with European regulatory authorities in preparation for the filing of an MAA with the EMA in the second half of 2015 and to continue discussions with the FDA to determine a potential regulatory path forward in the United States, as discussed in Note 1, the Company extended the end date of the estimated performance period through which the balance of deferred revenue will be amortized from June 30, 2015 to September 30, 2016. As a result, the quarterly amortization was adjusted to $0.9 million per quarter, commencing with the quarter ended September 30, 2014, from the previous amortization rate of $2.0 million per quarter.

Revenue participation right payments will be made to RPI when and if vosaroxin is commercialized, at a rate of 6.75% of net sales of vosaroxin, on a product-by-product and country-by-country basis world-wide through the later of: (a) the expiration of the last to expire of certain specifically identified patents; (b) 10 years from the date of first commercial sale of such product in such country; or (c) the expiration of all applicable periods of data, market or other regulatory exclusivity in such country with respect to such product.

7. License Agreements

Overview

In August 2004, the Company entered into a collaboration agreement with Biogen Idec MA, Inc. (“Biogen Idec”) to discover, develop and commercialize small molecule inhibitors of the human protein Raf kinase, including family members Raf-1, A-Raf, B-Raf and C-Raf (collectively “Raf”) and up to five additional targets that play a role in oncology and immunology indications (the “Biogen Idec OCA”). In connection with the Company’s June 2008 restructuring, the parties agreed to terminate the research obligations and related funding as of June 30, 2008.

In March 2011, as part of a series of agreements among the Company, Biogen Idec and Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, (“Millennium”), the Company entered into: (a) an amended and restated collaboration agreement with Biogen Idec (the “Biogen Idec 1st ARCA”); (b) a license agreement with Millennium (the “Millennium Agreement”); and (c) a termination and transition agreement among the Company, Biogen Idec and Millennium (the “Termination and Transition Agreement”).

The Termination and Transition Agreement provided for (a) the termination of Biogen Idec’s exclusive rights under the Biogen Idec OCA to all discovery programs under such agreement other than for small molecule inhibitors of the human protein Bruton’s tyrosine kinase (“BTK”); (b) the permitted assignment to Millennium of all related Company collaboration assets and rights to Raf kinase and the human protein phosphoinositide-dependent kinase-1 (“PDK1”); and (c) the payment of $4.0 million upfront from Millennium to the Company, which was recorded as revenue in March 2011.

Biogen Idec

The Biogen Idec 1st ARCA amended and restated the Biogen Idec OCA, to provide for the discovery, development and commercialization of small molecule BTK inhibitors. Under this agreement, the Company no longer has research obligations, but licenses granted to Biogen Idec with respect to the research collaboration under the Biogen Idec OCA (other than the licenses transferred to Millennium under the Millennium Agreement) remain in effect.

In June 2012, the Company received an event-based payment of $1.5 million from Biogen Idec for the advancement of pre-clinical work in connection with the Biogen Idec 1st ARCA. Under this agreement, the Company is eligible to receive up to an additional $58.5 million in pre-commercialization event-based payments related to the development by Biogen Idec of the first two indications for licensed products against the BTK target. The Company is also eligible to receive royalty payments depending on related product sales, if any.

In December 2013, the Company entered into a second amended and restated collaboration agreement with Biogen Idec (the “Biogen Idec 2nd ARCA”), to provide the Company with an exclusive worldwide license to develop, manufacture and commercialize

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SNS-062, a BTK inhibitor synthesized under the Biogen Idec 1st ARCA, solely for oncology indications. The Company may be required to make a $2.5 million milestone payment depending on its development of SNS-062 and royalty payments depending on related product sales of SNS-062. All other of Sunesis’ rights and obligations contained in the Biogen Idec 1st ARCA remain unchanged, except that potential future royalty payments to Sunesis were reduced to equal those amounts due to Biogen Idec for potential future sales of SNS-062.

Millennium

Under the Millennium Agreement, the Company granted exclusive licenses to products against two oncology targets originally developed under the Biogen Idec OCA, Raf and PDK1, under substantially the same terms as under the Biogen Idec OCA.

In January 2014, the Company entered into an amended and restated license agreement with Millennium (the “Amended Millennium Agreement”), to provide the Company with an exclusive worldwide license to develop and commercialize preclinical inhibitors of PDK1. In connection with the execution of the Amended Millennium Agreement, the Company paid an upfront fee and may be required to make up to $9.2 million in pre-commercialization milestone payments depending on its development of PDK1 inhibitors and royalty payments depending on related product sales, if any.

With respect to the Raf target product rights that were originally licensed to Millennium under the Millennium Agreement, the Company may in the future receive up to $57.5 million in pre-commercialization event-based payments related to the development by Millennium of the first two indications for each of the licensed products directed against the Raf target and royalty payments depending on related product sales. Millennium is currently conducting a Phase 1 clinical study of an oral investigative drug, MLN2480, which is licensed to them under the Amended Millennium Agreement.

8. Notes Payable

In October 2011, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation (collectively, the “Lenders”), under which the Company could borrow up to $25.0 million in two tranches (the “Loan Facility”). The first tranche of $10.0 million was funded upon closing of the transaction in October 2011, and the second tranche of $15.0 million was drawn by the Company in September 2012. In connection with the Loan Agreement, the Lenders were granted a perfected first priority security interest in substantially all of the Company’s assets, other than intellectual property.

The interest rates for the first and second tranche are 8.95% and 9.00% per annum, respectively. Payments under the Loan Agreement are monthly in arrears and were interest-only until February 1, 2013, followed by 32 equal monthly payments of principal and interest from March 1, 2013 to the scheduled maturity date of October 1, 2015. In addition, a final payment equal to $937,500 will be due on October 1, 2015, or such earlier date as specified in the Loan Agreement. The weighted average annual effective interest rate on the notes payable, including the amortization of the debt discounts and accretion of the final payment, is 13.9%.

Aggregate future minimum payments due under the Loan Facility as of December 31, 2014 were as follows (in thousands):

Year ending December 31,	Total
2015	$	8,814
Total minimum payments		8,814
Less amount representing interest		(352	)
Notes payable, gross		8,462
Unamortized discount on notes payable		(84	)
Accretion of final payment		879
Notes payable, balance		9,257
Less current portion of notes payable		(9,257	)
Non-current portion of notes payable	$	—

On February 27, 2015, the Company entered into a third amendment (the “Amendment”), to the Loan Agreement with the Lenders. The Amendment modifies the loan repayment terms to be interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. See Note 14 for further details.

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9. Commitments and Contingencies

Commitments

The Company’s operating lease obligations as of December 31, 2014 relate solely to the leasing of office space in a building at 395 Oyster Point Boulevard in South San Francisco, California, which is currently the Company’s headquarters. In January 2014, a lease for 15,378 square feet was entered into with an expiry date of April 30, 2015. In June 2014, the lease was amended to extend the expiration date to June 30, 2015, and to add 6,105 square feet of additional office space within the same building, and in January 2015, the lease was further amended to extend the expiration date to December 31, 2015. The amended lease also includes an option to extend the lease for an additional six months, at a predetermined price, if exercised within a certain period.

Aggregate non-cancelable future minimum rental payments under the operating lease as of December 31, 2014 were as follows (in thousands):

Year Ending December 31,	Payments
2015	$	247
Total rental payments	$	247

The Company recognizes rent expense on a straight-line basis. The Company recorded rent expense of $0.4 million, $0.3 million and $0.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Contingencies

From time to time, the Company may be involved in legal proceedings, as well as demands, claims and threatened litigation, which arise in the normal course of its business or otherwise. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on the Company’s results of operations and financial condition. Regardless of outcome, litigation can have an adverse impact on the Company because of the defense costs, diversion of management resources and other factors. The Company is not currently involved in any material legal proceedings.

10. Stockholders’ Equity

Preferred Stock

The Company has 10,000,000 shares of authorized preferred stock available for issuance in one or more series. Upon issuance, the Company can determine the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. There were no shares of preferred stock outstanding as of December 31, 2014 and 2013.

Common Stock

Holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders of the Company. Subject to the preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably such dividends, if any, as may be declared by the Board of Directors. Under the terms of the Loan Agreement with the Lenders, the Company is precluded from paying cash dividends without the prior written consent of the Lenders.

Underwritten Offering

On March 4, 2014, the Company completed an underwritten offering of 4,650,000 shares of common stock, each with two accompanying warrants to purchase one share of the Company’s common stock at exercise prices of $8.50 (Series A) and $12.00 (Series B) per share, respectively. The purchase price for each share of common stock and two accompanying warrants was $9.25. Gross proceeds from the sale were $43.0 million, and net proceeds were $40.0 million, after deducting the underwriting discount and offering expenses.

The warrants became exercisable on a gross exercise basis upon unblinding of the VALOR trial, which occurred on October 6, 2014. The Series A warrants expired unexercised on December 4, 2014. The Series B warrants will expire on or before the later of 30 days following any final date assigned by the Food and Drug Administration as the Prescription Drug User Fee Act action date for vosaroxin (the “PDUFA date”) and September 4, 2015, but in no event later than March 4, 2016. The common stock and accompanying warrants have both been classified to stockholders’ equity (deficit) in the Company’s balance sheet.

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Controlled Equity Offerings

In August 2011, the Company entered into a Controlled Equity Offering^SM sales agreement (the “Sales Agreement”), with Cantor Fitzgerald & Co. (“Cantor”), as agent and/or principal, pursuant to which the Company could issue and sell shares of its common stock having an aggregate gross sales price of up to $20.0 million. In April 2013, the Sales Agreement was amended to provide for an increase of $30.0 million in the aggregate gross sales price under the Sales Agreement. The Company will pay Cantor a commission of 3.0% of the gross proceeds from any common stock sold through the Sales Agreement, as amended.

During the year ended December 31, 2014, the Company sold an aggregate of 5,113,876 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.88 per share for gross proceeds of $14.7 million and net proceeds of $14.3 million, after deducting Cantor’s commission. As of December 31, 2014, $6.8 million of common stock remained available to be sold under this facility.

In January and February 2015, the Company sold an aggregate of 1,579,124 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.75 per share for gross proceeds of $4.3 million and net proceeds of $4.2 million, after deducting Cantor’s commission. As of February 27, 2015, $2.5 million of common stock remained available to be sold under the Sales Agreement, as amended, subject to certain conditions as specified in the agreement.

2010 Offering

In October 2010, the Company completed an underwritten offering, pursuant to which the Company issued an aggregate of 7,357,610 shares of common stock and warrants to purchase 3,678,798 shares of common stock, for aggregate gross proceeds of $15.5 million (the “2010 Offering”). Net proceeds from the sale were $14.2 million, after deducting underwriting discounts and offering expenses. The warrants have an exercise price of $2.52 per share, and expire in October 2015.

The warrants have been classified as a derivative liability on the Company’s balance sheet due to potential cash settlement of the warrants on terms, which do not include a cash limit, and upon the occurrence of certain transactions, as specified in the warrant agreements. At each balance sheet date, the estimated fair value of the outstanding warrants is determined using the Black-Scholes model and recorded to the balance sheet, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss. During the year ended December 31, 2014, warrants to purchase an aggregate of 179,427 shares of common stock that were issued in connection with the 2010 Offering were exercised, resulting in cash proceeds to the Company of $452,000. As of December 31, 2014, warrants to purchase an aggregate of 2,920,051 shares of common stock issued in connection with the 2010 Offering remained outstanding, with an estimated fair value of $3.5 million.

Equity Incentive Plans

The Company grants options to purchase shares of its common stock primarily to: (i) new employees, of which 25% of the shares subject to such options become exercisable on the first anniversary of the vesting commencement date, and 1/48th of the shares subject to such options become exercisable each month over the remainder of the four-year vesting period, (ii) existing employees, of which 1/48th of the shares subject to such options become exercisable each month following the date of grant over a four-year vesting period, (iii) new non-employee members of the board of directors, of which 50% of the shares subject to such options become exercisable on each of the first and second anniversary of the vesting commencement date, and (iv) continuing non-employee members of the board of directors, of which 1/24th of the shares subject to such options become exercisable each month following the date of grant over a two-year vesting period.

On March 15, 2011, the Company’s Board of Directors adopted, and on June 3, 2011, the Company’s stockholders approved, the 2011 Equity Incentive Plan (the “2011 Plan”). The 2011 Plan is intended as the successor to and continuation of the Company’s 1998 Stock Plan, 2001 Stock Plan, 2005 Equity Incentive Award Plan and 2006 Employment Commencement Incentive Plan (collectively, the “Prior Plans”). No additional stock awards will be granted under the Prior Plans.

The Company initially reserved a total of 6,041,856 shares of common stock for issuance under the 2011 Plan, which is the sum of (i) the 539,803 shares remaining available as of the Effective Date under the Prior Plans, (ii) an additional 4,400,000 new shares, and (iii) that portion of the 1,102,053 shares underlying stock options granted and currently outstanding under the Prior Plans that expire or terminate for any reason prior to exercise or settlement or that are forfeited because of the failure to meet a contingency or condition required to vest such shares.

The number of shares of common stock available for issuance under the 2011 Plan automatically increases on January 1st of each year for a period of 10 years commencing on January 1, 2012 by an amount equal to: (i) 4.0% of the Company’s outstanding shares of common stock on December 31st of the preceding calendar year, or (ii) a lesser amount determined by the Board of

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Directors. On January 1, 2014 and 2013, in accordance with the above, the number of shares of common stock available for issuance under the 2011 Plan was increased by 2,173,764 and 2,062,609 shares, respectively.

During the year ended December 31, 2014, options to purchase 3,840,500 shares of the Company’s common stock were granted under the 2011 Plan. As of December 31, 2014, there were 672,273 shares available for future grants under the 2011 Plan.

Employee Stock Purchase Plans

On March 5, 2011, the Company’s Board of Directors adopted, and on June 3, 2011, the Company’s stockholders approved, the 2011 Employee Stock Purchase Plan (the “2011 ESPP”). The 2011 ESPP is intended as the successor to the Company’s 2005 Employee Stock Purchase Plan, which was terminated on June 3, 2011.

The 2011 ESPP permits eligible employees to purchase common stock at a discount through payroll deductions during defined offering periods. Eligible employees can purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the common stock at (i) the beginning of a 12-month offering period, or (ii) at the end of one of the two related 6-month purchase periods. No participant in the 2011 ESPP may be issued or transferred shares of common stock valued at more than $25,000 per calendar year. The initial offering under the 2011 ESPP commenced on June 13, 2011 and ended on May 31, 2012. Subsequent 12-month offerings commenced or will commence on or around June 1st of each year.  

The Company initially reserved a total of 500,000 shares of common stock for issuance under the 2011 ESPP. The number of shares of common stock available for issuance under the 2011 ESPP automatically increases on January 1st of each year for a period of 10 years commencing on January 1, 2012 by an amount equal to: (i) 1.0% of the Company’s outstanding shares of common stock on December 31st of the preceding calendar year, or (ii) a lesser amount determined by the Board of Directors. On January 1, 2014 and 2013, in accordance with the above, the number of shares of common stock available for issuance under the 2011 ESPP was increased by 271,720 and nil shares, respectively.

A total of 99,049 shares were issued under the 2011 ESPP during the year ended December 31, 2014. As of December 31, 2014, there were 431,672 shares available for future issuance under the ESPP.

Warrants

Warrants to purchase shares of the Company’s common stock outstanding as of December 31, 2014 were as follows (in thousands, except per share amounts):

			Exercise Price
Date Issued	Shares		Per Share		Expiration
August 2005		14	$	54.60	August 2015
October 2010		2,920	$	2.52	October 2015
March 2014		4,650	$	12.00	March 2016
April 2009		2,876	$	1.32	April 2016
October 2009		1,438	$	1.32	October 2016
Total warrants outstanding and exercisable		11,898

Reserved Shares

Shares of the Company’s common stock reserved for future issuance as of December 31, 2014 were as follows (in thousands):

	Shares
	Available				Total
	for Future		Outstanding		Shares
	Grant		Securities		Reserved
Warrants		—		11,898		11,898
Stock option plans		672		10,584		11,256
Employee stock purchase plan		432		—		432
Total reserved shares of common stock		1,104		22,482		23,586

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11. Stock-Based Compensation

Overview

Employee stock-based compensation expense is calculated based on the grant-date fair value of awards ultimately expected to vest, reduced for estimated forfeitures, and is recorded on a straight-line basis over the vesting period of the awards. Forfeitures are estimated at the time of grant, based on historical option cancellation information, and revised in subsequent periods if actual forfeitures differ from those estimates. The following table summarizes stock-based compensation expense related to the Company’s stock-based awards for the periods indicated (in thousands):

	Year ended December 31,
	2014		2013		2012
Research and development	$	2,201	$	1,598	$	1,030
General and administrative		3,681		1,983		1,372
Employee stock-based compensation expense		5,882		3,581		2,402
Non-employee stock-based compensation expense		337		304		322
Total stock-based compensation expense	$	6,219	$	3,885	$	2,724

Fair Value of Awards

The Company determines the fair value of stock-based awards on the grant date using the Black-Scholes model, which is impacted by the Company’s stock price, as well as assumptions regarding a number of highly subjective variables. The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model, and resulting weighted-average and total estimated grant date fair values of employee stock options granted during the periods indicated:

	Year Ended December 31,
	2014			2013			2012
Assumptions:
Expected term (years)		5.2			4.7			5.4
Expected volatility		88.1	%		90.0	%		88.7	%
Risk-free interest rate		1.7	%		1.0	%		1.1	%
Expected dividend yield		0.0	%		0.0	%		0.0	%
Fair value:
Weighted-average estimated grant date fair value per    share	$	3.18		$	3.63		$	1.46
Options granted to employees (in thousands)		3,676			1,785			2,310
Total estimated grant date fair value (in thousands)	$	11,704		$	6,472		$	3,377

The estimated fair value of stock options that vested in the years ended December 31, 2014, 2013 and 2012, was $2.6 million, $3.4 million and $2.1 million, respectively. The Company based its assumptions for the expected term on historical cancellation and exercise data, and the contractual term and vesting terms of the awards. Expected volatility is based on historical volatility of the Company’s common stock, as well as that for a mature peer group of companies in the same industry. The Company does not anticipate paying any cash dividends in the foreseeable future, and therefore uses an expected dividend yield of zero.

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Option Plan Activity

The following table summarizes stock option activity for the Company’s stock option plans in the periods presented (in thousands, except per share amounts):

				Weighted		Weighted
				Average		Average
	Number			Exercise		Remaining		Aggregate
	of			Price Per		Contractual		Intrinsic
	Shares			Share		Term (Years)		Value
Outstanding as of December 31, 2013		7,611		$	3.61
Options granted		3,840		$	4.54
Options exercised		(565	)	$	2.17
Options forfeited or expired		(302	)	$	7.13
Outstanding as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Vested and expected to vest as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Exercisable as of December 31, 2014		5,701		$	3.86		6.57	$	2,075

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (i.e., the difference between the Company’s closing stock price on the last trading day of the period and the exercise price, multiplied by the number of in-the-money options) that would have been received by option holders if they had exercised all their options on December 31, 2014.

The intrinsic value of options exercised during the years ended December 31, 2014, 2013 and 2012 was $2.7 million, $0.3 million and $0.2 million, respectively. As the Company believes it is more likely than not that no stock option related tax benefits will be realized, the Company does not record any net tax benefits related to exercised options.

Total estimated unrecognized stock-based compensation cost related to unvested stock options was $12.2 million as of December 31, 2014, which is expected to be recognized over the respective vesting terms of each award. The weighted average term of the unrecognized stock-based compensation expense is 2.6 years.

12. Income Taxes

Loss before the provision for income taxes consisted of the following (in thousands):

	Year Ended December 31,
	2014			2013			2012
U.S. operations	$	(32,696	)	$	(29,963	)	$	(43,951	)
Foreign operations		(10,306	)		(4,635	)		—
Loss before provision for income taxes	$	(43,002	)	$	(34,598	)	$	(43,951	)

No provision for income taxes was recorded in the periods presented due to tax losses incurred in each period. The income tax provision differs from the amount computed by applying the statutory income tax rate of 34% to pre-tax loss as follows (in thousands):

	Year Ended December 31,
	2014			2013			2012
Tax at statutory rate	$	(14,620	)	$	(11,763	)	$	(14,943	)
Current year net operating losses and temporary differences    for which no tax benefit is recognized		14,104			12,457			5,351
Foreign tax rate differential		3,504			1,499			—
Deferred revenue		(1,934	)		(2,706	)		6,672
Change in fair value of warrant liability		(1,313	)		(16	)		2,570
Other permanent differences		259			529			350
Provision for income taxes	$	—		$	—		$	—

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Deferred income taxes reflect the net tax effects of loss and credit carry-forwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2014			2013
Deferred tax assets:
Federal and state net operating loss carry-forwards	$	138,066		$	123,490
Federal and state research credit carry-forwards		12,964			12,064
Capitalized research costs		5,199			5,119
Deferred revenue		2,394			4,668
Stock-based compensation		4,358			3,212
Property and equipment		129			133
Accrued liabilities		481			341
Gross deferred tax assets		163,591			149,027
Valuation allowance		(163,591	)		(149,027	)
Net deferred tax assets	$	—		$	—

Realization of the deferred tax assets is dependent upon future taxable income, if any, the amount and timing of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The net valuation allowance increased by approximately $14.6 million, $12.6 million and $13.7 million during the years ended December 31, 2014, 2013 and 2012, respectively.

As of December 31, 2014, the Company had federal net operating loss carry-forwards of $364.5 million and federal research and development tax credit carry-forwards of $8.1 million. If not utilized, the federal net operating loss and tax credit carry-forwards will expire at various dates beginning in 2018. As of December 31, 2014, the Company had state net operating loss carry-forwards of $235.8 million, which begin to expire in 2015, and state research and development tax credit carry-forwards of $7.2 million, which do not expire.

Utilization of these net operating loss and tax credits carry-forwards may be subject to a substantial annual limitation due to the ownership change rules under Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”). The limitations are applicable if an “ownership change,” as defined in the Code, is deemed to have occurred or occurs in the future. The annual limitation may result in the expiration of net operating loss and credit carry-forwards before they can be utilized.

The Company recognizes the financial statement effect of tax positions when it is more likely than not that the tax positions will be sustained upon examination by the appropriate taxing authorities. As of December 31, 2014 and 2013, the Company had no unrecognized tax positions.

The Company files U.S. federal and California tax returns.  The Company’s wholly owned subsidiaries, Sunesis Europe Limited and Sunesis Pharmaceuticals (Bermuda) Ltd., are currently not required to file tax returns. To date, neither the Company nor any of its subsidiaries have been audited by the Internal Revenue Service, any state income tax authority or tax authority in the related jurisdictions. Due to net operating loss carry-forwards, substantially all of the Company’s tax years remain open to federal tax examination.

13. Guarantees and Indemnification

As permitted under Delaware law and in accordance with the Company’s Bylaws, the Company indemnifies its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The indemnification agreements with the Company’s officers and directors terminate upon termination of their employment, but the termination does not affect claims for indemnification relating to events occurring prior to the effective date of termination. The maximum amount of potential future indemnification is unlimited; however, the Company’s officer and director insurance policy reduces the Company’s exposure and may enable the Company to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification agreements is minimal. In addition, in the ordinary course of business the Company enters into agreements, such as licensing agreements, clinical trial agreements and certain services agreements, containing standard indemnifications provisions. The Company believes that the likelihood of an adverse judgment related to such indemnification provisions is remote. Accordingly, the Company has not recorded any liabilities for any of these agreements as of December 31, 2014.

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14. Subsequent Events

On February 27, 2015, the Company entered into a third amendment (the “Amendment”), to the Loan Agreement with the Lenders. The Amendment modifies the loan repayment terms to be interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. In addition, the final payment will be increased from $937,500 (3.75%) to $1,162,500 (4.65%) of the total loan facility, and will become due on the new maturity date, or such earlier date specified in the Loan Agreement. If the Company repays all or a portion of the loan prior to February 29, 2016 as part of a refinancing with another lender, a prepayment fee equal to 2% of the then outstanding principal balance will be due to the Lenders. As a result of the Amendment, the Lenders were issued five-year warrants to purchase an aggregate of up to 61,467 shares of the Company’s common stock at a per share exercise price of $2.22.

In January and February 2015, the Company sold an aggregate of 1,579,124 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.75 per share for gross proceeds of $4.3 million and net proceeds of $4.2 million, after deducting Cantor’s commission. See Note 10 for further details.

In January 2015, the lease for the Company’s facility at 395 Oyster Point Boulevard in South San Francisco, California was amended to extend the expiration date to December 31, 2015. See Note 9 for further details.

15. Selected Quarterly Financial Data (unaudited, and in thousands, except per share amounts)

The following table sets forth the Company’s unaudited consolidated financial results for the last eight fiscal quarters.

	Three Months Ended
	Mar. 31,			June 30,			Sep. 30,			Dec. 31,			Mar. 31,			June 30,			Sep. 30,			Dec. 31,
	2014			2014			2014			2014			2013			2013			2013			2013
Revenue	$	1,995		$	1,989		$	854		$	896		$	1,989		$	1,989		$	1,989		$	1,989
Net loss:
Basic	$	(14,573	)	$	(11,781	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(8,190	)	$	(7,607	)	$	(7,177	)
Diluted	$	(14,573	)	$	(12,114	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(9,336	)	$	(8,329	)	$	(8,257	)
Shares used in computing net loss per    common share:
Basic		56,313			60,246			60,549			63,041			51,587			51,630			51,698			54,060
Diluted		56,313			61,895			60,549			63,041			51,587			53,268			53,271			55,573
Net loss per common share:
Basic	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.16	)	$	(0.15	)	$	(0.13	)
Diluted	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.18	)	$	(0.16	)	$	(0.15	)

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

Not applicable.

ITEM 9A. CONTROLS AND PROCEDURES

Disclosure Controls and Procedures

Based on their evaluation as of December 31, 2014, our Chief Executive Officer and Chief Financial Officer, with the participation of management, have concluded that, subject to the limitations described below, our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Securities Exchange Act) were effective at the reasonable assurance level to ensure the information required to be disclosed by us in reports that we file or submit under the Exchange is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission rules and forms.

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Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as defined in Rules 13a-15(f) and 15d-15(f) under the Securities Exchange Act. Internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles in the United States.

Under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, we conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2014. Management based its assessment on the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) in Internal Control—Integrated Framework. Based on this evaluation, our management concluded that as of December 31, 2014, our internal control over financial reporting was effective at the reasonable assurance level.

The effectiveness of our internal control over financial reporting as of December 31, 2014 has been audited by Ernst & Young LLP, our independent registered public accounting firm, as stated in their attestation report, which is included herein.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting during the quarter ended December 31, 2014 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Limitations on the Effectiveness of Controls

Our disclosure controls and procedures provide our Chief Executive Officer and Chief Financial Officer with only reasonable assurances that our disclosure controls and procedures will achieve their objectives. However, our management, including our Chief Executive Officer and Chief Financial Officer, does not expect that our disclosure controls and procedures or our internal control over financial reporting can or will prevent all human error. A control system, no matter how well designed and implemented, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. Furthermore, the design of a control system must reflect the fact that there are internal resource constraints, and the benefit of controls must be weighed relative to their corresponding costs. Because of the limitations in all control systems, no evaluation of controls can provide complete assurance that all control issues and instances of error, if any, within our company are detected. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur due to human error or mistake. Additionally, controls, no matter how well designed, could be circumvented by the individual acts of specific persons within the organization. The design of any system of controls is also based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated objectives under all potential future conditions.

70

Report of Independent Registered Public Accounting Firm

The Board of Directors and Stockholders of Sunesis Pharmaceuticals, Inc.

We have audited Sunesis Pharmaceuticals, Inc.’s internal control over financial reporting as of December 31, 2014, based on criteria established in Internal Control — Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) (the COSO criteria). Sunesis Pharmaceuticals, Inc.’s management is responsible for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the company’s internal control over financial reporting based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

In our opinion, Sunesis Pharmaceuticals, Inc. maintained, in all material respects, effective internal control over financial reporting as of December 31, 2014, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated balance sheets of Sunesis Pharmaceuticals, Inc. as of December 31, 2014 and 2013, and the related consolidated statements of operations and comprehensive loss, stockholders’ equity (deficit), and cash flows for each of the three years in the period ended December 31, 2014 of Sunesis Pharmaceuticals, Inc. and our report dated March 12, 2015 expressed an unqualified opinion thereon.

/s/ ERNST & YOUNG LLP

Redwood City, California

March 12, 2015

ITEM 9B. OTHER INFORMATION

None.

71

PART III

Certain information required by Part III is omitted from this report because we will file with the SEC a definitive proxy statement pursuant to Regulation 14A, or the Proxy Statement, not later than 120 days after the year ended December 31, 2014, and certain information included therein is incorporated herein by reference.

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

Information responsive to this item regarding directors and director nominees, executive officers, the board of directors and its committees, and certain corporate governance matters is incorporated herein by reference to the information set forth under the captions “Election of Nominees to the Board of Directors,” “Information About the Board of Directors and Corporate Governance” and “Certain Information with Respect to Executive Officers” in our definitive Proxy Statement.

Code of Business Conduct & Ethics

We have adopted a Code of Business Conduct & Ethics which applies to all of our directors, officers and employees. A copy of our Code of Business Conduct & Ethics can be found on our website, www.sunesis.com, in the section titled “Investors & Media” under the subsection titled “Corporate Governance”. Information found on our website is not incorporated by reference into this report. In addition, we intend to promptly disclose (1) the nature of any amendment to our Code of Business Conduct & Ethics that applies to our principal executive officer, principal financial officer, principal accounting officer or persons performing similar functions and (2) the nature of any waiver, including an implicit waiver, from a provision of our Code of Business Conduct & Ethics that is granted to one of these specified officers, the name of such person who is granted the waiver and the date of the waiver on our website in the future.

All additional information required by this Item 10 will be set forth in our definitive Proxy Statement and is incorporated in this report by reference.

ITEM 11. EXECUTIVE COMPENSATION

Information responsive to this item is incorporated herein by reference to the information set forth under the captions “Executive Compensation and Related Information” and “Information About the Board of Directors and Corporate Governance” in our definitive Proxy Statement.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

Ownership of Sunesis Securities

Information responsive to this item is incorporated herein by reference to the information set forth under the caption “Security Ownership of Certain Beneficial Owners and Management” in our definitive Proxy Statement.

72

Equity Compensation Plan Information

The following table provides certain information with respect to our equity compensation plans in effect as of December 31, 2014:

	(A)			(B)		(C)
						Number of Securities
						Remaining Available for
	Number of Securities					Future Issuance Under
	to be Issued upon			Weighted Average		EquityCompensation Plans
	Exercise of			Exercise Price of		(Excluding Securities
Plan Category	Outstanding Options			Outstanding Options		Reflected in Column A)
Equity Compensation Plans Approved    by Stockholders(1)		10,583,763	(2)	$	3.93		1,103,945	(3)
Equity Compensation Plans Not    Approved by Stockholders		—		$	—		—
Total		10,583,763		$	3.93		1,103,945

(1) Includes securities issuable under our 2011 Equity Incentive Plan, or 2011 Plan, and 2011 Employee Stock Purchase Plan, or ESPP.

(2) Excludes purchase rights currently accruing under the ESPP. Offering periods under the ESPP are 12-month periods, which are comprised of two six-month purchase periods. Eligible employees may purchase shares of common stock at a price equal to 85% of the lower of the fair market value of the common stock at the beginning of each offering period or the end of each semi-annual purchase period. No participant in the ESPP may be issued or transferred shares of common stock valued at more than $25,000 per calendar year.

(3) Includes (i) 672,273 shares of common stock available for issuance under our 2011 Plan and (ii) 431,672 shares of common stock available for issuance under our ESPP. Beginning in 2012, the number of shares of common stock reserved under the 2011 Plan automatically increases on January 1st of each year by an amount equal to: (i) 4.0% of our shares of common stock outstanding on December 31st of the preceding calendar year, or (ii) a lesser amount determined by our Board of Directors. The number of shares of common stock reserved under our ESPP automatically increases on January 1st of each year by an amount equal to: (i) 1.0% of our shares of common stock outstanding on December 31st of the preceding calendar year, or (ii) a lesser amount determined by our Board of Directors.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

Information responsive to this item is incorporated herein by reference to the information set forth under the captions “Certain Relationships and Related Party Transactions” and “Information About the Board of Directors and Corporate Governance” in our definitive Proxy Statement.

ITEM 14. PRINCIPAL ACCOUNTING FEES AND SERVICES

Information responsive to this item is incorporated herein by reference to the information set forth under the caption “Independent Registered Public Accounting Firm” in our definitive Proxy Statement.

73

PART IV

ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES

Exhibits and Financial Statement Schedules:

(a)(1)    Financial Statements

	Page
Report of Independent Registered Public Accounting Firm	49
Consolidated Balance Sheets	50
Consolidated Statements of Operations and Comprehensive Loss	51
Consolidated Statements of Stockholders’ Equity (Deficit)	52
Consolidated Statements of Cash Flows	53
Notes to Consolidated Financial Statements	54

(a)(2)    Financial Statement Schedules

All financial statement schedules are omitted because they are not applicable, or the information is included in the financial statements or notes thereto.

(a)(3)    Exhibits

A list of exhibits filed with this report or incorporated herein by reference is found in the Exhibit Index immediately following the signature page of this report.

74

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, Sunesis Pharmaceuticals, Inc. has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized on March 12, 2015.

SUNESIS PHARMACEUTICALS, INC.
By:	/S/ ERIC H. BJERKHOLT
	Eric H. Bjerkholt
	Executive Vice President, Corporate Development
	and Finance, Chief Financial Officer

POWER OF ATTORNEY KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Daniel N. Swisher, Jr. and Eric H. Bjerkholt, and each of them, as his true and lawful attorneys-in-fact and agents, with full power of substitution for him, and in his name in any and all capacities, to sign any and all amendments to this Annual Report on Form 10-K, and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done therewith, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, and any of them or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities on the dates indicated.

Signature	Title	Date
/S/ JAMES W. YOUNG, PH.D.	Chairman of the Board	March 12, 2015
James W. Young, Ph.D.
/S/ DANIEL N. SWISHER, JR	President, Chief Executive Officer and Director (Principal Executive Officer)	March 12, 2015
Daniel N. Swisher, Jr.
/S/ ERIC H. BJERKHOLT	Executive Vice President, Corporate Development and Finance, Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)	March 12, 2015
Eric H. Bjerkholt
/S/ STEVE CARCHEDI	Director	March 12, 2015
Steve Carchedi
/S/ MATTHEW K. FUST	Director	March 12, 2015
Matthew K. Fust
/S/ STEVEN B. KETCHUM, PH.D	Director	March 12, 2015
Steven B. Ketchum, Ph. D.
/S/ HELEN S. KIM	Director	March 12, 2015
Helen S. Kim
/S/ DAYTON MISFELDT	Director	March 12, 2015
Dayton Misfeldt
/S/ HOMER L. PEARCE, PH.D.	Director	March 12, 2015
Homer L. Pearce, Ph.D.
/S/ DAVID C. STUMP, M.D.	Director	March 12, 2015
David C. Stump, M.D.

75

EXHIBIT INDEX

		Incorporated By Reference
Exhibit Number	Exhibit Description	Form		File No.		Exhibit		Filing Date		Filed Herewith
3.1	Amended and Restated Certificate of Incorporation of the Registrant		10-K/A		000-51531		3.1		5/23/2007
3.2	Amended and Restated Bylaws of the Registrant		8-K		000-51531		3.2		12/11/2007
3.3	Certificate of Designation of the Series A Preferred Stock of the Registrant		8-K		000-51531		3.3		4/3/2009
3.4	Certificate of Amendment to the Amended and Restated Certificate of Incorporation of the Registrant		S-8		333-160528		3.4		7/10/2009
3.5	Certificate of Amendment to the Certificate of Designation of the Series A Preferred Stock of the Registrant		8-K		000-51531		3.4		11/2/2009
3.6	Certificate of Amendment to the Certificate of Designation of the Series A Preferred stock of the Registrant		8-K		000-51531		3.5		1/21/2010
3.7	Certificate of Amendment to the Amended and Restated Certificate of Incorporation of the Registrant		8-K		000-51531		3.1		2/14/2011
4.1	Reference is made to Exhibits 3.1, 3.2, 3.3, 3.4, 3.5, 3.6 and 3.7 above.
4.2	Specimen Common Stock certificate of the Registrant		10-K		000-51531		4.2		3/29/2011
4.3	Form of Series A Common Stock Purchase Warrant		8-K		000-51531		4.1		2/27/2014
4.4	Form of Series B Common Stock Purchase Warrant		8-K		000-51531		4.2		2/27/2014
4.5	Form of Warrant Agency Agreement by and between the Registrant and American Transfer & Trust & Company, LLC		8-K		000-51531		4.3		2/27/2014
10.1*	2001 Stock Plan and Form of Stock Option Agreement		S-1		333-121646		10.2		12/23/2004
10.2*	2005 Equity Incentive Award Plan, as amended, and Form of Stock Option Agreement		10-K/A		000-51531		10.3		4/30/2009
10.3*	Employee Stock Purchase Plan and Enrollment Form		10-Q		000-51531		10.4		11/9/2006
10.4*	Form of Indemnification Agreement for directors and executive officers		S-1		333-121646		10.5		12/23/2004
10.5†	License Agreement, dated October 14, 2003, by and between the Registrant and Sumitomo Dainippon Pharma Co., Ltd. (formerly known as Dainippon Pharmaceutical Co., Ltd.)		S-1/A		333-121646		10.36		4/29/2005
10.6	Warrant, dated August 25, 2005, issued to Horizon Technology Funding Company II LLC		S-1/A		333-121646		10.40		9/1/2005
10.7	Warrant, dated August 25, 2005, issued to Horizon Technology Funding Company III LLC		S-1/A		333-121646		10.41		9/1/2005
10.8	Warrant, dated August 25, 2005, issued to Oxford Finance Corporation		S-1/A		333-121646		10.42		9/1/2005
10.9*	Amended and Restated 2006 Employment Commencement Incentive Plan		10-K/A		000-51531		10.32		4/30/2009

76

		Incorporated By Reference
Exhibit Number	Exhibit Description	Form		File No.		Exhibit		Filing Date		Filed Herewith
10.10*	Forms of Stock Option Grant Notice and Stock Option Agreement under the 2005 Equity Incentive Award Plan		8-K		000-51531		10.52		9/19/2007
10.11*	Second Amended and Restated Executive Severance Benefits Agreement, dated December 24, 2008, by and between Registrant and Daniel N. Swisher, Jr.		10-K		000-51531		10.44		4/3/2009
10.12*	Second Amended and Restated Executive Severance Benefits Agreement, dated December 24, 2008, by and between Registrant and Eric H. Bjerkholt		10-K		000-51531		10.45		4/3/2009
10.13*	Forms of Stock Option Grant Notice and Stock Option Agreement for Automatic Grants to Outside Directors under the 2005 Equity Incentive Award Plan		10-Q		000-51531		10.69		11/7/2008
10.14*	Forms of Stock Option Grant Notice and Stock Option Agreement under the Amended and Restated 2006 Employment Commencement Incentive Plan		8-K		000-51531		10.71		12/23/2008
10.15	Form of Warrant to purchase shares of Common Stock		8-K		000-51531		10.2		4/3/2009
10.16	Underwriting Agreement, dated September 30, 2010, by and between the Registrant and Cowen and Company LLC		8-K		000-51531		1.1		10/1/2010
10.17	Form of Warrant to Purchase Common Stock of the Registrant		8-K		000-51531		4.1		10/1/2010
10.18	Master Services Agreement, dated June 21, 2010, by and between the Registrant and Icon Clinical Research Limited		10-K		000-51531		10.54		3/29/2011
10.19	First Amendment to Master Services Agreement, dated August 1, 2008, by and between the Registrant and Aptuit, Inc. (as assignee of Quintiles, Inc.)		10-Q		000-51531		10.3		5/12/2011
10.20	Amended and Restated Collaboration Agreement, dated March 31, 2011, by and between the Registrant and Biogen Idec MA Inc.		10-Q/A		000-51531		10.4		6/30/2011
10.21	License Agreement, dated March 31, 2011, by and between the Registrant and Millennium Pharmaceuticals, Inc.		10-Q/A		000-51531		10.5		6/30/2011
10.22	Termination and Transition Agreement, dated March 31, 2011, by and between the Registrant, Biogen Idec MA Inc. and Millennium Pharmaceuticals, Inc.		10-Q		000-51531		10.6		5/12/2011
10.23*	Sunesis Pharmaceuticals, Inc. 2011 Equity Incentive Plan		S-8		333-174732		99.1		6/6/2011
10.24*	Sunesis Pharmaceuticals, Inc. 2011 Employee Stock Purchase Plan		S-8		333-174732		99.2		6/6/2011
10.25	Sales Agreement, dated August 11, 2011, between Sunesis Pharmaceuticals, Inc. and Cantor Fitzgerald & Co.		8-K		000-51531		10.1		8/11/2011
10.26	Loan and Security Agreement among the Registrant, Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, dated as of October 18, 2011		8-K		000-51531		10.1		10/19/2011

77

		Incorporated By Reference
Exhibit Number	Exhibit Description	Form		File No.		Exhibit		Filing Date		Filed Herewith
10.27*	Executive Severance Benefits Agreement, dated January 31, 2012, by and between the Registrant and Adam R. Craig		10-K		000-51531		10.56		3/14/2012
10.28*	Forms of Stock Option Grant Notice and Option Agreement under the 2011 Equity Incentive Plan		10-K		000-51531		10.57		3/14/2012
10.29*	Forms of Restricted Stock Unit Grant Notice and Restricted Stock Unit Agreement under the 2011 Equity Incentive Plan		10-K		000-51531		10.58		3/14/2012
10.30†	Revenue Participation Agreement, dated March 29, 2012, by and between Sunesis Pharmaceuticals, Inc. and RPI Finance Trust		10-Q		000-51531		10.6		5/15/2012
10.31	First Amendment to Loan and Security Agreement Among the Registrant, Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, dated March 29, 2012		10-Q		000-51531		10.7		5/15/2012
10.32*	Amendment to Executive Severance Benefit Agreement, dated October 24, 2012, by and between the Registrant and Adam R. Craig		10-K		000-51531		10.61		3/13/2013
10.33	Amendment No. 1 to Sales Agreement, dated August 11, 2011, between the Registrant and Cantor Fitzgerald & Co., dated April 10, 2013		8-K		000-51531		10.1		4/10/2013
10.34	Termination and Registration Rights Agreement, dated June 7, 2013, by and among the Registrant and the investors identified on the signature pages thereto		8-K		000-51531		10.1		6/11/2013
10.35	Non-Employee Director Compensation Information		10-Q		000-51531		10.3		8/2/2013
10.36	Second Amendment to Loan and Security Agreement, dated October 18, 2011, by and between the Registrant, Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation, dated September 23, 2013		10-Q		000-51531		10.1		11/12/2013
10.37*	Offer Letter, dated January 10, 2014, by and between the Registrant and Joseph DePinto		10-K		000-51531		10.44		3/6/2014
10.38*	Executive Severance Benefits Agreement, dated March 6, 2014, by and between the Registrant and Joseph DePinto		10-K		000-51531		10.45		3/6/2014
10.39†	Second Amended and Restated Collaboration Agreement, dated December 16, 2013, by and between the Registrant and Biogen Idec MA Inc.		10-K		000-51531		10.46		3/6/2014
10.40†	Amended and Restated License Agreement, dated January 8, 2014, by and between the Registrant and Millennium Pharmaceuticals, Inc.		10-K		000-51531		10.47		3/6/2014
10.41	Lease Agreement, dated January 14, 2014, by and between the Registrant and Kashiwa Fudosan America, Inc., for office space located at 395 Oyster Point Boulevard, South San Francisco, California		10-K		000-51531		10.45		3/6/2014
10.42*	Sunesis Pharmaceuticals, Inc. 2014 Bonus Program		8-K		000-51531		10.1		3/24/2014

78

		Incorporated By Reference
Exhibit Number	Exhibit Description	Form		File No.		Exhibit		Filing Date		Filed Herewith
10.43	First Amendment to Office Lease, dated June 3, 2014, by and between the Registrant and Kashiwa Fudosan America, Inc., for office space located at 395 Oyster Point Boulevard, South San Francisco, California		10-Q		000-51531		10.1		8/05/2014
10.44	Second Amendment to Office Lease, dated January 28, 2015, by and between the Registrant and Kashiwa Fudosan America, Inc., for office space located at 395 Oyster Point Boulevard, South San Francisco, California										X
21.1	Subsidiaries of the Registrant		10-Q		000-51531		21.1		8/02/2013
23.1	Consent of Independent Registered Public Accounting Firm										X
24.1	Power of Attorney										(included on Signature page)
31.1	Certification of Chief Executive Officer pursuant to Rule 13a-14(a) or Rule 15d-14(a) of the Exchange Act										X
31.2	Certification of Chief Financial Officer pursuant to Rule 13a-14(a) or Rule 15d-14(a) of the Exchange Act										X
32.1#	Certification of Chief Executive Officer and Chief Financial Officer pursuant to 13a-14(b) or 15d-14(b) of the Exchange Act										X
101.INS	XBRL Instance Document
101.SCH	XBRL Taxonomy Extension Schema Document
101.CAL	XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF	XBRL Taxonomy Extension Definition Linkbase Document
101.LAB	XBRL Taxonomy Extension Labels Linkbase Document
101.PRE	XBRL Taxonomy Extension Presentation Linkbase Document

* Management contract, compensatory plan or arrangement.

† Portions of the exhibit have been omitted pursuant to a request for confidential treatment. The omitted information has been filed separately with the Securities and Exchange Commission.

# In accordance with Item 601(b)(32)(ii) of Regulation S-K and SEC Release Nos. 33-8238 and 34-47986, Final Rule; Management’s Reports on Internal Control over Financial Reporting and Certification of Disclosure in Exchange Act Periodic Reports, the Certification furnished in Exhibit 32.1 hereto is deemed to accompany this Form 10-K and will not be filed for purposes of Section 18 of the Exchange Act. Such certification will not be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act, except to the extent that the registrant specifically incorporates it by reference.

79

EX-10.44

Exhibit 10.44

OYSTER POINT MARINA PLAZA

Second Amendment to Office Lease

THIS SECOND AMENDMENT TO OFFICE LEASE (the “Second Amendment”) is made and entered into as of January 28, 2015, by and between KASHIWA FUDOSAN AMERICA, INC., a California corporation (“Landlord”) and SUNESIS PHARMACEUTICALS, INC., a Delaware corporation (“Tenant”).

Recitals

A.Landlord and Tenant have heretofore entered into that certain lease dated August 1, 2013 (the “Lease”) for premises described as Suite 400 (the “Premises”), initially containing approximately 15,378 rentable square feet, in the building located at 395 Oyster Point Boulevard, South San Francisco, California (the “Building”), which forms part of the office building complex commonly known as Oyster Point Marina Plaza (the “Complex”).

B.The Lease has heretofore been amended by that certain First Amendment to Office Lease dated as of June 3, 2014 (the “First Amendment”), under which the parties agreed to extend the Term of the Lease through June 30, 2015 and to expand the Premises by the addition thereto of Suite 300 containing approximately 6,105 rentable square feet of space.

C.The parties mutually desire to amend the terms of the Lease to extend its Term and effect certain other related changes, all on and subject to the terms and conditions hereof.

Agreement

Now, therefore, in consideration of the mutual terms and conditions herein contained and of other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows:

1Effect of Amendment.  Landlord and Tenant agree that, notwithstanding anything contained in the Lease to the contrary, the provisions set forth below will be deemed to be part of the Lease and shall supersede, to the extent they differ, any contrary provisions in the Lease.  Terms defined in the Lease and the First Amendment shall have the same meanings in this Second Amendment, unless a different definition is set forth in this Second Amendment.  A true, complete, and correct copy of the Lease is attached hereto as Exhibit A and incorporated herein by reference.

2Effective Date.  The amendments and changes specified in this Second Amendment shall become effective on July 1, 2015 (the “Effective Date”).  Notwithstanding the foregoing, this Second Amendment shall constitute the fully-binding agreement and contract of the parties from and after the date of the parties’ execution and delivery of this Second Amendment to each other.

3Summary Table.  The Table set forth in § 1.2 of the Lease as heretofore amended is hereby superseded and replaced in its entirety by the following table, which shall constitute the Table under§ 1.2 of the Lease for all purposes from and after the Effective Date of this Second Amendment:

Periods	Suite No.	RSF	USF	Monthly Base Rent	Tenant’s Share Bldg	Tenant’s Share Complex	Base Year
July 1, 2015 through December 31, 2015	400	15,378	13,372	$31,524.90	6.608%	3.311%	2014
	300	6,105	5,231	$12,515.25	2.623%	1.314%	2014

In the event of any conflict between the terms contained in the Table and the terms contained in subsequent paragraphs of this Second Amendment, the terms of the Table shall control, except as may be expressly varied in any subsequent paragraphs of this Second Amendment.

4EXTENSION OF LEASE TERM. The Term of the Lease specified in §1.4 of the Lease as heretofore amended is hereby ex tended for an additional period of six (6) months commencing on July 1, 2015, and the Expiration Date of the Lease is hereby amended accordingly to December 31, 2015.

4.1Option to Renew.  Tenant is hereby granted one (1) option to extend (the “Extension Option”) the Term of the Lease with respect to the entire Premises for one (1) additional period of six (6) months (the “Extension Period”).  The Extension Period term shall begin the first day following the Expiration Date as extended hereunder and shall take effect on the same terms and conditions as are in effect under the Lease immediately prior to the first Extension Period, except that the Base Rent specified as to each suite comprising the Premises in the Table above shall be increased to $2.15 per rentable square foot per month.

(a) Exercise of Option.  The Extension Option may be exercised only by (i) delivering in person to Landlord’s Building Manager in the Building Office written notice of Tenant’s irrevocable election to exercise no later than September 1, 2015, and (ii) collecting and retaining in exchange for such notice of exercise an original written receipt therefor signed and dated by Landlord’s Building Manager.  Tenant’s exercise of its Extension Option shall not be effective or valid if there is any deviation in the timing or manner of exercise prescribed herein.

(b) Failure to Exercise.  If Tenant shall fail validly and timely to exercise the Option herein granted, said Option shall terminate and shall be null and void and of no further force and effect.

(c) Default.  Tenant’s exercise of the Option shall, at Landlord’s election, be null and void if Tenant is in Default on the date of Tenant’s notice of exercise or at any time thereafter and prior to commencement of the Extension Period.  Tenant’s exercise of the Extension Option shall not operate to cure any Default by Tenant nor to extinguish or impair any rights or remedies of Landlord arising by virtue of such Default.  If the Lease or Tenant’s right to possession of the Premises shall terminate before Tenant shall have exercised the Extension Option, then immediately upon such termination the Extension Option shall simultaneously terminate and become null and void.

(d) Time.  Time is of the essence of the Ex tension Option granted hereunder.

5Extension Term Base Year. As specified in the Table above, the Base Year for the purposes calculating Tenant’s Share of Increased Operating Expenses and Increased Taxes under Article 4 of the Lease as heretofore amended shall be calendar year 2014 from and after the Effective Date.

6Extension Term Base Rent. The Base Rent for the Premises specified in § 1.5 of the Lease as heretofore a mended shall be the amounts specified as Monthly Base Rent in the Table above for the various periods and spaces set forth in the Table from and after the Effective Date.

7Use of Furniture. Tenant’s right to use the Furniture as set forth in 8 of the First Amendment shall remain unchanged through the Expiration Date as ex tended hereunder.

8Condition of Premises. Tenant shall accept the Premises, any existing Improvements in the Premises, and the Systems and Equipment serving the same in an “as is” condition on the Effective Date, and Landlord shall have no obligation to improve, alter, remodel, or otherwise modify the Premises in connection with Tenant’s continued occupancy of the Premises from and after the July 1, 2015.

9Security Deposit. Tenant’s Security Deposit specified in§ 5.1 of the Lease as heretofore amended shall remain unchanged in consequence of the parties’ execution and delivery of this Second Amendment to each other.

10Access Inspection Disclosure. Pursuant to California Civil Code § 1938, Landlord hereby notifies Tenant that, as of the date of this Second Amendment, the Premises have not undergone inspection by a “Certified Access Specialist” to determine whether the Premises meet all applicable construction-related accessibility standards under California Civil Code§ 55.53, and the Premises have not been determined to meet all applicable construction-related accessibility standards pursuant to Civil Code§ 55.53.

11No Disclosure. Tenant agrees that it shall not disclose any of the matters set forth in this Second Amendment or disseminate or distribute any information concerning the terms, details, or conditions hereof to any person, firm, or entity without obtaining the express written approval of Landlord.

12Defined Terms. Terms used herein that are defined in the Lease shall have the meanings therein defined, unless a different definition is set forth in this Second Amendment.  In the event of any conflict between the provisions of the Lease, and this Second Amendment, the terms of this Second Amendment shall prevail.

13Survival. Warranties, representations, agreen1ents, and obligations contained in this Second Amendment shall survive the execution and delivery of this Second Amendment and shall survive any and all performances in accordance with this Second Amendment.

14Counterparts. This Second Amendment may be executed in any number of counterparts, which each severally and all together shall constitute one and the same Second Amendment.

15Attorneys’ Fees. If any party obtains a judgement against any other party or parties by reason of breach of this Second Amendment, reasonable attorneys’ fees and costs as fixed by the court shall be included in such judgement against the losing party or parties.

16Successors. This Second Amendment and the terms and provisions hereof shall inure to the benefit of and be binding upon the heirs, successors, and assigns of the parties.

17Authority. Each of the individuals executing this Second Amendment represents and warrants that he or she is authorized to execute this Second Amendment on behalf of the party for whom he or she is executing this Second Amendment and that by his or her signature such party is legally bound by the terms, covenants, and conditions of this Second Amendment.

18Governing Law. This Second Amendment shall be construed and enforced in accordance with the laws of the State of California.

19Continuing Validity of Lease. Except as expressly modified herein, the Lease remains in full force and effect.

20Conflicts. In the event of any conflict between the provisions of the Lease and those of this Second Amendment, the terms and provisions of this Second Amendment shall control.

21Landlord’s Representative. Tenant acknowledges and agrees that, in executing this Second Amendment, TAK Development, Inc., a California corporation, is acting solely in its capacity as Landlord’s authorized attorney-in-fact.  TAK Developn1ent, Inc. is not acquiring or assuming any legal liability or obligation to any other party executing this Second Amendment, and any claim or demand of any such other party arising under or with respect to this Second Amendn1ent shall be n1ade and enforced solely against Landlord.

22Exhibits. The following exhibits have been attached to this Second Amendment by the parties prior to their execution and deliver of the same to each other, which are incorporated herein by reference:

Exhibit A-- The Lease

23Whole Agreement. The mutual obligations of the parties as provided herein are the sole consideration for this Second Amendment, and no representations, promises, or inducements have been made by the parties other than as appear in this Second Amendment, which supersedes any previous negotiations.  There have been no representations made by the Landlord or understandings made between the parties other than those set forth in this Second Amendment.  This Second Amendment may not be amended except in writing signed by all the parties.

In witness whereof, the parties have executed this Second Amendment as of the date first above written.

Landlord: KASHIWA FUDOSAN AMERICA, INC., a California corporation By:TAK Development, Inc., a
California corporation Its:Attorney-in-Fact By:/s/ Yujin Yamaai
Yujin Yamaai, Vice President Tenant: SUNESIS PHARMACEUTICALS, INC., a California corporation By:   /s/ Eric Bjerkholt
[name typed] Its:CFO  

/s/Robert L. Delsman_
Robert L Delsman Approved as to Legal Form and Sufficiency Berkeley, California 2015.01.28 15:46:17  08’00’

EX-23.1

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the following Registration Statements:

(1) Registration Statement (Form S-3 No. 333-168191) of Sunesis Pharmaceuticals, Inc.,

(2) Registration Statement (Form S-3 No. 333-187854) of Sunesis Pharmaceuticals, Inc.,

(3) Registration Statement (Form S-3 No. 333-194166) of Sunesis Pharmaceuticals, Inc.,

(4) Registration Statement (Form S-3 No. 333-195779) of Sunesis Pharmaceuticals, Inc.,

(5) Registration Statement (Form S-8 No. 333-128647) pertaining to the 1998 Stock Plan, the 2001 Stock Plan, the 2005 Equity Incentive Award Plan and the Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.,

(6) Registration Statement (Form S-8 No. 333-132679) pertaining to the 2006 Employment Commencement Incentive Plan of Sunesis Pharmaceuticals, Inc.,

(7) Registration Statement (Form S-8 No. 333-138758) pertaining to the 2001 Stock Plan, the 2005 Equity Incentive Award Plan and the Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.,

(8) Registration Statement (Form S-8 No. 333-145404) pertaining to the 2005 Equity Incentive Award Plan, the Amended and Restated 2006 Employment Commencement Incentive Plan and the Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.,

(9) Registration Statement (Form S-8 No. 333-150834) pertaining to the 2005 Equity Incentive Award Plan, the Amended and Restated 2006 Employment Commencement Incentive Plan and the Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.,

(10) Registration Statement (Form S-8 No. 333-160528) pertaining to the 2005 Equity Incentive Award Plan and the Amended and Restated 2006 Employment Commencement Incentive Plan of Sunesis Pharmaceuticals, Inc.,

(11) Registration Statement (Form S-8 No. 333-174732) pertaining to the 2011 Equity Incentive Plan and the 2011 Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.,

(12) Registration Statement (Form S-8 No. 333-180101) pertaining to the 2011 Equity Incentive Plan of Sunesis Pharmaceuticals, Inc.,

(13) Registration Statement (Form S-8 No. 333-187234) pertaining to the 2011 Equity Incentive Plan of Sunesis Pharmaceuticals, Inc., and

(14) Registration Statement (Form S-8 No. 333-195781) pertaining to the 2011 Equity Incentive Plan and the 2011 Employee Stock Purchase Plan of Sunesis Pharmaceuticals, Inc.;

of our reports dated March 12, 2015, with respect to the consolidated financial statements of Sunesis Pharmaceuticals, Inc., and the effectiveness of internal control over financial reporting of Sunesis Pharmaceuticals, Inc., included in this Annual Report (Form 10-K) for the year ended December 31, 2014.

/s/ Ernst & Young LLP

Redwood City, California

March 12, 2015

EX-31.1

Exhibit 31.1

Certification of Chief Executive Officer

I, Daniel N. Swisher, Jr., certify that:

1. I have reviewed this annual report on Form 10-K of Sunesis Pharmaceuticals, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b) any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: March 12, 2015	/s/ DANIEL N. SWISHER, JR.
	Daniel N. Swisher, Jr.
	President and Chief Executive Officer

EX-31.2

Exhibit 31.2

Certification of Chief Financial Officer

I, Eric H. Bjerkholt, certify that:

1. I have reviewed this annual report on Form 10-K of Sunesis Pharmaceuticals, Inc.;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a) designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c) evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d) disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b) any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: March 12, 2015	/s/ ERIC H. BJERKHOLT
	Eric H. Bjerkholt
	Executive Vice President, Corporate Development and Finance, Chief Financial Officer and Corporate Secretary

EX-32.1

Exhibit 32.1

Certification of Chief Executive Officer and Chief Financial Officer

Pursuant to the requirement set forth in Rule 13a-14(b) of the Securities Exchange Act of 1934, as amended, (the “Exchange Act”) and Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. §1350), Daniel N. Swisher, Jr., President and Chief Executive Officer and Eric H. Bjerkholt, Executive Vice President, Corporate Development and Finance and Chief Financial Officer, of Sunesis Pharmaceuticals, Inc. (the “Company”), each hereby certifies that, to the best of his knowledge:

1. The Company’s Annual Report on Form 10-K for the period ended December 31, 2014 (the “Annual Report”), to which this Certification is attached as Exhibit 32.1, fully complies with the requirements of Section 13(a) or Section 15(d) of the Exchange Act; and

2. The information contained in the Annual Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: March 12, 2015	/s/ DANIEL N. SWISHER, JR.
	Daniel N. Swisher, Jr. President and Chief Executive Officer
Date: March 12, 2015	/s/ ERIC H. BJERKHOLT
	Eric H. Bjerkholt
	Executive Vice President, Corporate Development and Finance, Chief Financial Officer and Corporate Secretary

This certification accompanies the Form 10-K to which it relates, is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of Sunesis Pharmaceuticals, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (whether made before or after the date of the Form 10-K), irrespective of any general incorporation language contained in such filing.

XML

Financial Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Sales of available-for-sale securities	$ 0	$ 0	$ 0
2010 Offering [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrants exercised for cash, shares	179,427
Exercise of warrants for cash	$ 452,000

XML

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Related to Company's Stock-Based Awards (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	$ 6,219	$ 3,885	$ 2,724
Employee stock-based compensation expense [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	5,882	3,581	2,402
Non-employee stock-based compensation expense [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	337	304	322
Research and development [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	2,201	1,598	1,030
General and administrative [Member]
Share-based Compensation, Allocation and Classification in Financial Statements
Total stock-based compensation expense	$ 3,681	$ 1,983	$ 1,372

XML

Commitments and Contingencies - Aggregate Non-Cancelable Future Minimum Rental Payments under Operating Lease (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
2015	$ 247
Total minimum rental payments due under operating leases	$ 247

XML

Stock-Based Compensation - Summary of Weighted-Average and Total Estimated Grant Date Fair Values of Employee Stock Options Granted (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assumptions:
Expected dividend yield	0.00%
Fair value:
Options granted to employees (in thousands)	3,840,000
Stock Option Plans [Member]
Assumptions:
Expected term (years)	5 years 2 months 12 days	4 years 8 months 12 days	5 years 4 months 24 days
Expected volatility	88.10%	90.00%	88.70%
Risk-free interest rate	1.70%	1.00%	1.10%
Expected dividend yield	0.00%	0.00%	0.00%
Fair value:
Weighted-average estimated grant date fair value per share	$ 3.18	$ 3.63	$ 1.46
Stock Option Plans [Member] | Employee stock-based compensation expense [Member]
Fair value:
Options granted to employees (in thousands)	3,676,000	1,785,000	2,310,000
Total estimated grant date fair value (in thousands)	$ 11,704	$ 6,472	$ 3,377

XML

Notes Payable - Summary of Future Minimum Payments Under Loan Agreement (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Notes payable, balance	$ 9,257
Less current portion of notes payable	(9,257)	(9,018)
Non-current portion of notes payable		9,025
Notes payable [Member]
Debt Instrument [Line Items]
2015	8,814
Total minimum payments	8,814
Less amount representing interest	(352)
Notes payable, gross	8,462
Unamortized discount on notes payable	(84)
Accretion of final payment	$ 879

XML

Company Overview - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Date of incorporation	Feb. 10, 1998
Cash, cash equivalents and marketable securities	$ 43,000,000
Accumulated deficit	$ (522,697,000)	$ (479,695,000)
Maturity limits period	24 months
Dollars weighted average maturity limit period	12 months

XML

Stock-Based Compensation - Summary of Stock Option Activity for Company's Stock Option Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Number of Shares	7,611
Options granted, Number of Shares	3,840
Options exercised, Number of Shares	(565)
Options forfeited or expired, Number of Shares	(302)
Ending Balance, Number of Shares	10,584
Vested and expected to vest as of December 31, 2014, Number of Shares	10,584
Exercisable as of December 31, 2014, Number of Shares	5,701
Beginning Balance, Weighted Average Exercise Price Per Share	$ 3.61
Options granted, Weighted Average Exercise Price Per Share	$ 4.54
Options exercised, Weighted Average Exercise Price Per Share	$ 2.17
Options forfeited or expired, Weighted Average Exercise Price Per Share	$ 7.13
Ending Balance, Weighted Average Exercise Price Per Share	$ 3.93
Vested and expected to vest as of December31, 2014, Weighted Average Exercise Price Per Share	$ 3.93
Exercisable as of December31,2014,Weighted Average Exercise Price Per Share	$ 3.86
Ending Balance, Weighted Average Remaining Contractual Term (Years)	7 years 7 months 17 days
Vested and expected to vest as of December31, 2014, Weighted Average Remaining Contractual Term (Years)	7 years 7 months 17 days
Exercisable as of December31, 2014,Weighted Average Remaining Contractual Term (Years)	6 years 6 months 26 days
Ending Balance, Aggregated Intrinsic Value	$ 3,885
Vested and expected to vest as of December31,2014,Aggregate Intrinsic Value	3,885
Ending Balance, Exercisable, Aggregate Intrinsic Value	$ 2,075

XML

Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value of Company's Financial Assets Measured on Recurring Basis

The following tables summarize the estimated fair value of the Company’s financial assets measured on a recurring basis as of the dates indicated, which were comprised solely of available-for-sale marketable securities with remaining contractual maturities of one year or less (in thousands):

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2014	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	9,287		$	—	$	—		$	9,287
U.S. certificates of deposit	Level 1		6,360			—		—			6,360
U.S. corporate debt obligations	Level 2		11,789			—		(7	)		11,782
U.S. commercial paper	Level 2		2,898			—		—			2,898
Total available-for-sale securities			30,334			—		(7	)		30,327
Less amounts classified as cash equivalents			(9,532	)		—		—			(9,532	)
Amounts classified as marketable securities		$	20,802		$	—	$	(7	)	$	20,795

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2013	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	6,282		$	—	$	—		$	6,282
U.S. corporate debt obligations	Level 2		13,509			—		(4	)		13,505
U.S. commercial paper	Level 2		8,396			3		—			8,399
Foreign corporate debt obligations	Level 2		2,571			—		(2	)		2,569
Total available-for-sale securities			30,758			3		(6	)		30,755
Less amounts classified as cash equivalents			(6,583	)		—		—			(6,583	)
Amounts classified as marketable securities		$	24,175		$	3	$	(6	)	$	24,172

Summary of Available-for-Sale Securities in Unrealized Loss Position

The following table summarizes the available-for-sale securities that were in an unrealized loss position as of December 31, 2014, each having been in such a position for less than 12 months, and none deemed to be other-than-temporarily impaired (in thousands):

	Gross
	Unrealized		Estimated Fair
December 31, 2014	Losses		Value
U.S. corporate debt obligations	$	7	$	11,782
Total available-for-sale securities in an unrealized loss    position	$	7	$	11,782

Summary of Assumptions and Estimated Fair Value of Company's Financial Liabilities Measured on Recurring Basis

The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured on a recurring basis as of the dates indicated, which were comprised solely of a liability for warrants issued in connection with an underwritten equity offering completed in 2010 (see Note 10):

	December 31,			December 31,
	2014			2013
Inputs and assumptions:
Fair market value of Company’s common stock	$	2.55		$	4.74
Exercise price	$	2.52		$	2.52
Expected term (years)		0.8			1.8
Expected volatility		144.9	%		60.8	%
Risk-free interest rate		0.2	%		0.3	%
Expected dividend yield		0.0	%		0.0	%
Fair value:
Estimated fair value per warrant share	$	1.21		$	2.56
Shares underlying outstanding warrants classified as    liabilities (in thousands)		2,920			3,099
Total estimated fair value of outstanding warrants    (in thousands)	$	3,543		$	7,931

Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities

The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities for the periods indicated (in thousands):

	Warrant
	Liability
Balance as of December 31, 2012	$	8,070
Change in fair value of warrant liability		(96	)
Exercise of warrants		(43	)
Balance as of December 31, 2013		7,931
Change in fair value of warrant liability		(3,892	)
Exercise of warrants		(496	)
Balance as of December 31, 2014	$	3,543

XML

Stockholders' Equity - Additional Information 2 (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended
	Mar. 04, 2014	Oct. 31, 2010	Dec. 31, 2014	Jun. 03, 2011	Jan. 31, 2014	Jan. 31, 2013	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock issued			66,102,000				54,344,000
Proceeds from issuance of common stock and warrants in offering gross	$ 43,000,000	$ 15,500,000
Proceeds from issuance of common shares and warrants in offering, net	40,000,000
Warrants, exercise prices per share			$ 2.52				$ 2.52
Warrant liability			3,543,000				7,931,000
Number of shares of common stock reserved for issuance under latest plan			23,586,000
Shares Available for Future Grant			1,104,000
Options granted, Number of Shares			3,840,000
Stock Option Plans [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance under latest plan			11,256,000
Shares Available for Future Grant			672,000
Stock Option Plans [Member] | New Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option exercisable on first anniversary of vesting commencement date, percent			25.00%
Portion of option exercisable for each month over vesting period			0.020833333
Stock option plans, vesting period			4 years
Vesting rights			New employees, of which 25% of the shares subject to such options become exercisable on the first anniversary of the vesting commencement date, and 1/48th of the shares subject to such options become exercisable each month over the remainder of the four-year vesting period
Stock Option Plans [Member] | Existing Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Portion of option exercisable for each month over vesting period			0.020833333
Stock option plans, vesting period			4 years
Vesting rights			Existing employees, of which 1/48th of the shares subject to such options become exercisable each month following the date of grant over a four-year vesting period
Stock Option Plans [Member] | New Non-Employee Board Members [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plans, vesting period			2 years
Vesting rights			New non-employee members of the board of directors, of which 50% of the shares subject to such options become exercisable on each of the first and second anniversary of the vesting commencement date
Option exercisable on first and second anniversary of vesting commencement date, percent			50.00%
Stock Option Plans [Member] | Continuing Non-Employee Board Members [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Portion of option exercisable for each month over vesting period			0.041666667
Stock option plans, vesting period			2 years
Vesting rights			Continuing non-employee members of the board of directors, of which 1/24th of the shares subject to such options become exercisable each month following the date of grant over a two-year vesting period
2010 Offering [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock issued		7,357,610
Total warrants outstanding, shares		3,678,798	2,920,051
Proceeds from issuance of common stock and warrants in offering gross		15,500,000
Proceeds from issuance of common shares and warrants in offering, net		14,200,000
Warrants, maturity date		2015-10
Warrants, exercise prices per share		$ 2.52
Warrants exercised for cash, shares			179,427
Exercise of warrants for cash			452,000
Warrant liability			$ 3,500,000
2011 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance under latest plan				6,041,856
Shares Available for Future Grant			672,273	539,803
Shares of common stock available for issuance				4,400,000	2,173,764	2,062,609
Common stock available for issuance automatic increase period			10 years
Common stock available for issuance automatic increase maximum number of shares			4.00%
Options granted, Number of Shares			3,840,500
2011 Plan [Member] | Stock Option Plans [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Available for Future Grant				1,102,053

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Other Accrued Liabilities - Summary of Other Accrued Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Payables And Accruals [Abstract]
Accrued outside services	$ 2,656	$ 1,249
Accrued professional services	355	263
Other accruals	76	133
Total other accrued liabilities	$ 3,087	$ 1,645

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Financial Instruments - Fair Value of Company's Financial Assets Measured on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	$ 30,334	$ 30,758
Available-for-sale securities, Gross Unrealized Gains		3
Available-for-sale securities, Gross Unrealized Losses	(7)	(6)
Available-for-sale securities, Estimated Fair Value	30,327	30,755
Less amounts classified as cash equivalents, Amortized Cost	(9,532)	(6,583)
Amounts classified as marketable securities, Amortized Cost	20,802	24,175
Amounts classified as marketable securities, Gross Unrealized Gains		3
Amounts classified as marketable securities, Gross Unrealized Losses	(7)	(6)
Less amounts classified as cash equivalents, Estimated Fair Value	(9,532)	(6,583)
Amounts classified as marketable securities, Estimated Fair Value	20,795	24,172
Level 1 [Member] | Money market funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	9,287	6,282
Available-for-sale securities, Estimated Fair Value	9,287	6,282
Level 1 [Member] | U.S. certificates of deposit [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	6,360
Available-for-sale securities, Estimated Fair Value	6,360
Level 2 [Member] | U.S. corporate debt obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	11,789	13,509
Available-for-sale securities, Gross Unrealized Losses	(7)	(4)
Available-for-sale securities, Estimated Fair Value	11,782	13,505
Level 2 [Member] | U.S. commercial paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost	2,898	8,396
Available-for-sale securities, Gross Unrealized Gains		3
Available-for-sale securities, Estimated Fair Value	2,898	8,399
Level 2 [Member] | Foreign corporate debt obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale securities, Amortized Cost		2,571
Available-for-sale securities, Gross Unrealized Losses		(2)
Available-for-sale securities, Estimated Fair Value		$ 2,569

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Stockholders' Equity - Schedule of Warrants to Purchase Shares of Company's Common Stock (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Warrants, exercise prices per share	$ 2.52	$ 2.52
Common Stock [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	11,898,000
Common Stock [Member] | August 2005 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	14,000
Warrants, exercise prices per share	$ 54.60
Warrants Expiration Date	2015-08
Common Stock [Member] | October 2010 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	2,920,000
Warrants, exercise prices per share	$ 2.52
Warrants Expiration Date	2015-10
Common Stock [Member] | March 2014 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	4,650,000
Warrants, exercise prices per share	$ 12.00
Warrants Expiration Date	2016-03
Common Stock [Member] | April 2009 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	2,876,000
Warrants, exercise prices per share	$ 1.32
Warrants Expiration Date	2016-04
Common Stock [Member] | October 2009 [Member]
Class of Warrant or Right [Line Items]
Total warrants outstanding and exercisable, shares	1,438,000
Warrants, exercise prices per share	$ 1.32
Warrants Expiration Date	2016-10

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Income Taxes - Significant Components of Deferred Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Federal and state net operating loss carry-forwards	$ 138,066	$ 123,490
Federal and state research credit carry-forwards	12,964	12,064
Capitalized research costs	5,199	5,119
Deferred revenue	2,394	4,668
Stock-based compensation	4,358	3,212
Property and equipment	129	133
Accrued liabilities	481	341
Gross deferred tax assets	163,591	149,027
Valuation allowance	$ (163,591)	$ (149,027)

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Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Line Items]
Rent expense	$ 0.4	$ 0.3	$ 0.4
Original Operating Lease [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease, office space leased	15,378
Operating lease expiration date	Apr. 30, 2015
Operating lease agreement, original date	2014-01
Amended Operating Lease [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease, additional office space leased	6,105
Operating lease expiration date	Jun. 30, 2015
Operating lease agreement, date of amendment	2014-06
Lease property description	The amended lease also includes an option to extend the lease for an additional six months, at a predetermined price, if exercised within a certain period.
Further Amended Operating Lease [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease expiration date	Dec. 31, 2015
Operating lease agreement, date of amendment	2015-03

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Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”).

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), that will supersede most existing revenue recognition guidance under US GAAP. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. Entities electing the full retrospective adoption will apply the standard to each period presented in the financial statements. This means that entities will have to apply the new guidance as if it had been in effect since the inception of all its contracts with customers presented in the financial statements. Entities that elect the modified retrospective approach will apply the guidance retrospectively only to the most current period presented in the financial statements. This means that entities will have to recognize the cumulative effect of initially applying the new standard as an adjustment to the opening balance of retained earnings at the date of initial application. The new revenue standard will be applied to contracts that are in progress at the date of initial application. The standard will be effective for annual and interim periods beginning after December 15, 2016. The Company has yet to evaluate which adoption method it plans to use or the potential effect of the new standard on its consolidated financial statements.

In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”), which will require a reporting entity to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the reporting entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures. The standard will be effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has yet to evaluate the potential effect of the new standard on its consolidated financial statements.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Sunesis Europe Limited, a United Kingdom corporation, and Sunesis Pharmaceuticals (Bermuda) Ltd., a Bermuda corporation, as well as a Bermuda limited partnership, Sunesis Pharmaceuticals International LP. All intercompany balances and transactions have been eliminated in consolidation.

Segment Reporting

Management has determined that the Company operates as a single reportable segment.

Significant Estimates and Judgments

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the Company’s consolidated financial statements and accompanying notes thereto. Actual results could differ materially from these estimates. Estimates, assumptions and judgments made by management include those related to the valuation of equity and related instruments, revenue recognition, stock-based compensation and clinical trial accounting.

Cash Equivalents and Marketable Securities

The Company considers all highly liquid securities with original maturities of three months or less from the date of purchase to be cash equivalents, which generally consist of money market funds and corporate debt securities. Marketable securities consist of securities with original maturities of greater than three months, which may include U.S. and European government obligations and corporate debt securities.

Management determines the appropriate classification of securities at the time of purchase. The Company generally classifies its entire investment portfolio as available-for-sale. The Company views its available-for-sale portfolio as available for use in current operations. Accordingly, the Company classifies all investments as short-term, even though the stated maturity may be more than one year from the current balance sheet date. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported in accumulated other comprehensive income (loss), which is a separate component of stockholders’ equity (deficit).

The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in other income (expense), net in the statements of operations and comprehensive loss. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities, if any, are also recorded to other income (expense), net. The cost of securities sold is based on the specific-identification method.

Invoices for certain services provided to the Company are denominated in foreign currencies. To manage the risk of future movements in foreign exchange rates that would affect such amounts, the Company may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments defined in the Company’s investment policy. There is no guarantee that the related gains and losses will substantially offset each other, and the Company may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter. To date, the Company has purchased Euros and Euro-denominated obligations of foreign governments and corporate debt. As of December 31, 2014 and December 31, 2013, the Company held investments denominated in Euros with an aggregate fair value of $0 and $2.6 million, respectively. Any cash, cash equivalent and short-term investment balances denominated in foreign currencies are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are both recorded in other income (expense), net in the statements of operations and comprehensive loss.

Fair Value Measurements

The Company measures cash equivalents, marketable securities and warrant liabilities at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable GAAP:

Level 1 -	quoted prices (unadjusted) in active markets for identical assets and liabilities that can be accessed at the measurement date
Level 2 -	inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly
Level 3 -	unobservable inputs

The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets.

The fair value of the Company’s liability for warrants issued in connection with an underwritten offering completed in October 2010 (the “2010 Offering”) is determined using the Black-Scholes model, which requires inputs such as the expected term of the warrants, share price volatility, expected dividend yield and risk-free interest rate. As some of these inputs are unobservable, and require significant analysis and judgment to measure, these variables are classified as Level 3.

The carrying amounts of the Company’s financial instruments, including cash, prepayments, accounts payable, accrued liabilities, deferred revenue and notes payable approximated their fair value as of December 31, 2014 and December 31, 2013.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is determined using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the term of the lease.

Accounting for Royalty Agreement

The payment of $25.0 million by RPI under the Royalty Agreement (see Note 6) is non-refundable, and no revenue participation right payments will be made unless vosaroxin is commercialized. Accordingly, the payment received from RPI is being accounted for as a payment for the Company to use commercially reasonable efforts to commercialize vosaroxin. Therefore, the amount is to be deferred and recognized as revenue over the projected performance period under the agreement. The payment, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period. The fair value of the warrants was recorded to additional paid-in capital.

Accounting for Notes Payable

The accounting for certain fees and expenses related to the Loan Agreement (see Note 8) is as follows. The facility fee is being accounted for as a debt discount and classified within notes payable on the Company’s balance sheet. The fair value of the warrants issued in connection with the Loan Agreement have been recorded as a debt discount within notes payable and an increase to additional paid-in capital on the Company’s balance sheet. The debt discount is being amortized as interest expense over the term of the loan using the effective interest method. The final payment is being accreted as interest expense over the term of the loans using the effective interest method. The legal fees are being accounted for as deferred debt issuance costs within assets on the Company’s balance sheet and are being amortized as other income (expense), net over the term of the loans using the effective interest method.

Accounting for Equity Financing

In October 2010, the Company completed the 2010 Offering (see Note 10), in which the Company sold its common stock and warrants to purchase its common stock for aggregate gross proceeds of $15.5 million. Due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements, the warrants are being accounted for as a derivative liability as opposed to permanent equity. Outstanding warrants under this arrangement are revalued to their fair value each period end, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss.

Revenue Recognition

Revenue arrangements with multiple deliverables are accounted for in accordance with the Financial Accounting Standards Board Accounting Standards Codification, Subtopic 605-25, Multiple-Element Arrangements (“ASC 605-25”). Under ASC 605-25, revenue arrangements with multiple deliverables are divided into separate units of accounting based on whether certain criteria are met, including whether the delivered item has stand-alone value to the customer. Consideration is allocated among the separate units of accounting based on their respective fair value, and the applicable revenue recognition is applied to each of the separate units.

Non-refundable fees where the Company has no continuing performance obligations are recognized as revenues when collection is reasonably assured. In situations where continuing performance obligations exist, non-refundable fees are deferred and recognized ratably over the projected performance period.

Milestone payments from license or collaboration agreements which are substantive and at risk at the time the agreement is executed are recognized upon completion of the applicable milestone event. Royalty revenues, if any, will be recognized based on reported product sales by third-party licensees. Research funding from any future agreement will be recognized as the related research services are performed.

Research and Development

Research and development expense consists primarily of: (a) clinical trial costs, which include payments for work performed by contract research organizations (“CROs”), clinical trial sites, labs and other clinical service providers, and for drug packaging, storage and distribution; (b) drug manufacturing costs, which include costs for producing drug substance and drug product, and for stability and other testing; (c) personnel costs for related permanent and temporary employees; (d) other outside services and consulting costs; and (e) payments under license agreements. All research and development costs are expensed as they are incurred.

Clinical Trial Accounting

The Company records accruals for estimated clinical trial costs, which include payments for work performed by CROs and participating clinical trial sites. These costs are generally a significant component of research and development expense. Costs incurred for setting up clinical trial sites for participation in trials are generally non-refundable, and are expensed as incurred, with any refundable advances related to enrollment of the first patient recorded as prepayments and assessed for recoverability on a quarterly basis. Costs related to patient enrollment are accrued as patients progress through the clinical trial, including amortization of any first-patient prepayments. This amortization generally matches when the related services are rendered, however, these cost estimates may or may not match the actual costs incurred by the CROs or clinical trial sites, and if the Company has incomplete or inaccurate information, the clinical trial accruals may not be accurate. The difference between accrued expenses based on the Company’s estimates and actual expenses have not been significant to date.

Stock-Based Compensation

The Company grants options to purchase common stock to its employees, directors and consultants under its stock option plans. Under the Company’s Employee Stock Purchase Plan, eligible employees can also purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock at the beginning of a 12-month offering period or at the end of one of the two related six-month purchase periods.

The Company values these share-based awards using the Black-Scholes option valuation model (the “Black-Scholes model”). The determination of fair value of share-based payment awards on the date of grant using the Black-Scholes model is affected by the Company’s stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors and related estimated forfeitures.

Foreign Currency

Transactions that are denominated in a foreign currency are translated into U.S. dollars at the current exchange rate on the transaction date. Any foreign currency-denominated monetary assets and liabilities are subsequently remeasured at current exchange rates as of each balance sheet date, with gains or losses on foreign exchange recognized in other income (expense), net in the statements of operations and comprehensive loss.

Income Taxes

The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the differences between the tax basis of assets and liabilities and their basis for financial reporting. Deferred tax assets or liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which temporary differences are expected to be recovered or settled. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company’s policy is to recognize interest charges and penalties in other income (expense), net in the statements of operations and comprehensive loss.

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Guarantee and Indemnification - Additional Information (Detail) (USD $)	Dec. 31, 2014
Guarantees [Abstract]
Liabilities incurred in indemnification agreements	$ 0

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Royalty Agreement - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended	1 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2014	Sep. 30, 2012	Dec. 31, 2013
Royalty Agreement [Line Items]
Exercise price			$ 2.52		$ 2.52
Common stock, shares issued			66,102,000		54,344,000
Deferred revenue, amortized	$ 0.9	$ 2.0
Revenue participation right payments, rate			6.75%
Revenue participation right payments, term			10 years from the date of first commercial sale
Maximum term of revenue participation right payments			10 years
Royalty Agreement [Member]
Royalty Agreement [Line Items]
Revenue participation right payments			25.0	25.0
Fair value of warrants issued in connection with participation agreement			$ 3.1	$ 3.1
Number of warrants issued to RPI			2
Common stock, shares issued			777,107
Royalty Agreement [Member] | Warrant One [Member]
Royalty Agreement [Line Items]
Warrants Expiration Term			5 years
Warrant issued to purchase common stock			1,000,000
Exercise price			$ 3.48
Royalty Agreement [Member] | Warrant Two [Member]
Royalty Agreement [Line Items]
Warrants Expiration Term			5 years
Warrant issued to purchase common stock			1,000,000
Exercise price			$ 4.64

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Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Equity [Abstract]

Schedule of Warrants to Purchase Shares of Company's Common Stock

Warrants to purchase shares of the Company’s common stock outstanding as of December 31, 2014 were as follows (in thousands, except per share amounts):

			Exercise Price
Date Issued	Shares		Per Share		Expiration
August 2005		14	$	54.60	August 2015
October 2010		2,920	$	2.52	October 2015
March 2014		4,650	$	12.00	March 2016
April 2009		2,876	$	1.32	April 2016
October 2009		1,438	$	1.32	October 2016
Total warrants outstanding and exercisable		11,898

Shares of Common Stock Reserved for Future Issuance

Shares of the Company’s common stock reserved for future issuance as of December 31, 2014 were as follows (in thousands):

	Shares
	Available				Total
	for Future		Outstanding		Shares
	Grant		Securities		Reserved
Warrants		—		11,898		11,898
Stock option plans		672		10,584		11,256
Employee stock purchase plan		432		—		432
Total reserved shares of common stock		1,104		22,482		23,586

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Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2014

Commitments And Contingencies Disclosure [Abstract]

Aggregate Non-Cancelable Future Minimum Rental Payments under Operating Lease

Aggregate non-cancelable future minimum rental payments under the operating lease as of December 31, 2014 were as follows (in thousands):

Year Ending December 31,	Payments
2015	$	247
Total rental payments	$	247

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Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Estimated fair value of stock options, vested	$ 2,600,000	$ 3,400,000	$ 2,100,000
Payment of cash dividends	0
Dividend yield ratio	0.00%
Intrinsic value of options exercised	2,700,000	300,000	200,000
Tax benefits related to stock option exercised	0
Unrecognized stock-based compensation cost related to unvested stock options	$ 12,200,000
Weighted average term of unrecognized stock-based compensation expense	2 years 7 months 6 days

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License Agreements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Mar. 31, 2011	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2014	Jan. 31, 2014
License Agreement Terms [Member] | Millennium License Agreements [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Potential pre-commercialization payments receivable				$ 57.5
Potential pre-commercialization milestone payments payable					9.2
Biogen Idec And Millennium [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non refundable upfront amount recognized as revenue due to no further performance obligation	4.0
Biogen Idec [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Received and recognized milestone		1.5
Biogen Idec [Member] | License Agreement Terms [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Potential pre-commercialization payments receivable		58.5
Biogen Idec [Member] | Development Events [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone payment depending on development			$ 2.5

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Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock-Based Compensation Expense Related to Company's Stock-Based Awards

The following table summarizes stock-based compensation expense related to the Company’s stock-based awards for the periods indicated (in thousands):

	Year ended December 31,
	2014		2013		2012
Research and development	$	2,201	$	1,598	$	1,030
General and administrative		3,681		1,983		1,372
Employee stock-based compensation expense		5,882		3,581		2,402
Non-employee stock-based compensation expense		337		304		322
Total stock-based compensation expense	$	6,219	$	3,885	$	2,724

Summary of Weighted-Average and Total Estimated Grant Date Fair Values of Employee Stock Options Granted

The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model, and resulting weighted-average and total estimated grant date fair values of employee stock options granted during the periods indicated:

	Year Ended December 31,
	2014			2013			2012
Assumptions:
Expected term (years)		5.2			4.7			5.4
Expected volatility		88.1	%		90.0	%		88.7	%
Risk-free interest rate		1.7	%		1.0	%		1.1	%
Expected dividend yield		0.0	%		0.0	%		0.0	%
Fair value:
Weighted-average estimated grant date fair value per    share	$	3.18		$	3.63		$	1.46
Options granted to employees (in thousands)		3,676			1,785			2,310
Total estimated grant date fair value (in thousands)	$	11,704		$	6,472		$	3,377

Summary of Stock Option Activity for Company's Stock Option Plans

The following table summarizes stock option activity for the Company’s stock option plans in the periods presented (in thousands, except per share amounts):

				Weighted		Weighted
				Average		Average
	Number			Exercise		Remaining		Aggregate
	of			Price Per		Contractual		Intrinsic
	Shares			Share		Term (Years)		Value
Outstanding as of December 31, 2013		7,611		$	3.61
Options granted		3,840		$	4.54
Options exercised		(565	)	$	2.17
Options forfeited or expired		(302	)	$	7.13
Outstanding as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Vested and expected to vest as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Exercisable as of December 31, 2014		5,701		$	3.86		6.57	$	2,075

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Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Loss before Provision for Income Taxes

Loss before the provision for income taxes consisted of the following (in thousands):

	Year Ended December 31,
	2014			2013			2012
U.S. operations	$	(32,696	)	$	(29,963	)	$	(43,951	)
Foreign operations		(10,306	)		(4,635	)		—
Loss before provision for income taxes	$	(43,002	)	$	(34,598	)	$	(43,951	)

Income Tax Provision Amount Computed by Applying Statutory Income Tax Rate

The income tax provision differs from the amount computed by applying the statutory income tax rate of 34% to pre-tax loss as follows (in thousands):

	Year Ended December 31,
	2014			2013			2012
Tax at statutory rate	$	(14,620	)	$	(11,763	)	$	(14,943	)
Current year net operating losses and temporary differences    for which no tax benefit is recognized		14,104			12,457			5,351
Foreign tax rate differential		3,504			1,499			—
Deferred revenue		(1,934	)		(2,706	)		6,672
Change in fair value of warrant liability		(1,313	)		(16	)		2,570
Other permanent differences		259			529			350
Provision for income taxes	$	—		$	—		$	—

Significant Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2014			2013
Deferred tax assets:
Federal and state net operating loss carry-forwards	$	138,066		$	123,490
Federal and state research credit carry-forwards		12,964			12,064
Capitalized research costs		5,199			5,119
Deferred revenue		2,394			4,668
Stock-based compensation		4,358			3,212
Property and equipment		129			133
Accrued liabilities		481			341
Gross deferred tax assets		163,591			149,027
Valuation allowance		(163,591	)		(149,027	)
Net deferred tax assets	$	—		$	—

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Company Overview

12 Months Ended

Dec. 31, 2014

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Company Overview

1. Company Overview

Description of Business

Sunesis Pharmaceuticals, Inc. (the “Company” or “Sunesis”) was incorporated in the state of Delaware on February 10, 1998, and its facilities are located in South San Francisco, California. Sunesis is a biopharmaceutical company focused on the development and commercialization of new oncology therapeutics for the treatment of solid and hematologic cancers. The Company’s primary activities since incorporation have been conducting research and development internally and through corporate collaborators, in-licensing and out-licensing pharmaceutical compounds and technology, conducting clinical trials and raising capital.

In October 2014, the Company announced the results of a Phase 3, multi-national, randomized, double-blind, placebo-controlled, clinical trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory acute myeloid leukemia (the “VALOR trial”). The trial did not meet its primary endpoint of demonstrating a statistically significant improvement in overall survival, but based upon the favorable results of other predefined analyses of the data, Sunesis plans to meet with European regulatory authorities in preparation for the filing of a marketing authorization application (“MAA”) with the European Medicines Agency (“EMA”) in the second half of 2015. The Company is also currently engaged in discussions with the U.S. Food and Drug Administration (“FDA”) to determine a potential regulatory path forward in the United States.

Significant Risks and Uncertainties

The Company has incurred significant losses and negative cash flows from operations since its inception, and as of December 31, 2014, had cash, cash equivalents and marketable securities totaling $43.0 million and an accumulated deficit of $522.7 million.

The Company will need to raise substantial additional capital to pursue a regulatory strategy for the potential commercialization of QINPREZO^TM(vosaroxin), its product candidate for the potential treatment of acute myeloid leukemia, and to continue the development of vosaroxin and the Company’s other programs. The Company expects to finance its future cash needs primarily through equity issuances, debt arrangements, one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights to vosaroxin and its other development programs, or a combination of the above. However, the Company does not know whether additional funding will be available on acceptable terms, or at all. If the Company is unable to raise required funding on acceptable terms or at all, it will need to reduce operating expenses, enter into a collaboration or other similar arrangement with respect to development and/or commercialization rights to vosaroxin, outlicense intellectual property rights to vosaroxin or our other development programs, sell unsecured assets, or a combination of the above, or be forced to delay or reduce the scope of our vosaroxin development program, potentially including any regulatory filings related to the VALOR trial, and/or limit or cease our operations.

Concentrations of Credit Risk

In accordance with its investment policy, the Company invests cash that is not currently being used for operational purposes. The policy allows for the purchase of low risk debt securities issued by: (a) the United States and certain European governments and government agencies, and (b) highly rated banks and corporations, denominated in U.S. dollars, Euros or British pounds, subject to certain concentration limits. The policy limits maturities of securities purchased to no longer than 24 months and the weighted average maturity of the portfolio to 12 months. Management believes these guidelines ensure both the safety and liquidity of any investment portfolio the Company may hold.

Financial instruments that potentially subject the Company to concentrations of credit risk generally consist of cash, cash equivalents and marketable securities. The Company is exposed to credit risk in the event of default by the institutions holding its cash, cash equivalents and any marketable securities to the extent of the amounts recorded in the balance sheets.

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Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Data

The following table sets forth the Company’s unaudited consolidated financial results for the last eight fiscal quarters.

	Three Months Ended
	Mar. 31,			June 30,			Sep. 30,			Dec. 31,			Mar. 31,			June 30,			Sep. 30,			Dec. 31,
	2014			2014			2014			2014			2013			2013			2013			2013
Revenue	$	1,995		$	1,989		$	854		$	896		$	1,989		$	1,989		$	1,989		$	1,989
Net loss:
Basic	$	(14,573	)	$	(11,781	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(8,190	)	$	(7,607	)	$	(7,177	)
Diluted	$	(14,573	)	$	(12,114	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(9,336	)	$	(8,329	)	$	(8,257	)
Shares used in computing net loss per    common share:
Basic		56,313			60,246			60,549			63,041			51,587			51,630			51,698			54,060
Diluted		56,313			61,895			60,549			63,041			51,587			53,268			53,271			55,573
Net loss per common share:
Basic	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.16	)	$	(0.15	)	$	(0.13	)
Diluted	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.18	)	$	(0.16	)	$	(0.15	)

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Financial Instruments - Summary of Assumptions and Estimated Fair Value of Company's Financial Liabilities Measured on Recurring Basis (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Inputs and assumptions:
Fair market value of Company’s common stock	$ 2.55	$ 4.74
Exercise price	$ 2.52	$ 2.52
Expected term (years)	9 months 18 days	1 year 9 months 18 days
Expected volatility	144.90%	60.80%
Risk-free interest rate	0.20%	0.30%
Expected dividend yield	0.00%	0.00%
Fair value:
Estimated fair value per warrant share	$ 1.21	$ 2.56
Shares underlying outstanding warrants classified as liabilities (in thousands)	2,920	3,099
Total estimated fair value of outstanding warrants (in thousands)	$ 3,543	$ 7,931

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Stockholders' Equity - Shares of Common Stock Reserved for Future Issuance (Detail)	Dec. 31, 2014
Class of Stock [Line Items]
Shares Available for Future Grant	1,104,000
Outstanding Securities	22,482,000
Total Shares Reserved	23,586,000
Warrants to purchase shares of common stock [Member]
Class of Stock [Line Items]
Outstanding Securities	11,898,000
Total Shares Reserved	11,898,000
Employee Stock Option
Class of Stock [Line Items]
Shares Available for Future Grant	672,000
Outstanding Securities	10,584,000
Total Shares Reserved	11,256,000
Employee Stock Purchase Plan [Member]
Class of Stock [Line Items]
Shares Available for Future Grant	431,672
Total Shares Reserved	432,000

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CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 22,186	$ 15,121
Marketable securities	20,795	24,172
Prepaids and other current assets	1,223	1,199
Total current assets	44,204	40,492
Property and equipment, net	42	23
Deposits and other assets		10
Total assets	44,246	40,525
Current liabilities:
Accounts payable	3,177	953
Accrued clinical expense	3,112	4,750
Accrued compensation	2,287	1,719
Other accrued liabilities	3,087	1,645
Current portion of deferred revenue	3,418	7,956
Current portion of notes payable	9,257	9,018
Warrant liability	3,543	7,931
Total current liabilities	27,881	33,972
Non-current portion of deferred revenue	2,563	3,712
Non-current portion of notes payable		9,025
Commitments and contingencies (Note 9)
Stockholders’ equity (deficit):
Common stock, $0.0001 par value; 400,000 shares authorized as of December 31, 2014; 66,102 and 54,344 shares issued and outstanding as of December 31, 2014 and 2013, respectively	7	5
Additional paid-in capital	536,499	473,509
Accumulated other comprehensive loss	(7)	(3)
Accumulated deficit	(522,697)	(479,695)
Total stockholders’ equity (deficit)	13,802	(6,184)
Total liabilities and stockholders’ equity (deficit)	$ 44,246	$ 40,525

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Notes Payable - Additional Information (Detail) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014 Tranches Installment	Feb. 27, 2015 Loan	Oct. 31, 2011	Oct. 18, 2011	Sep. 30, 2012	Sep. 19, 2012
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 25,000,000
Number of tranches for maximum borrowing	2
Number of installments	32
Line of credit facility final payment	937,500
Subsequent Event
Debt Instrument [Line Items]
Expiration date		Oct. 01, 2016
Line of credit facility final payment	937,500	1,162,500
Interest only period start date		Mar. 01, 2015
Interest only period end date		Feb. 01, 2016
Number of remaining principal payments		8
Notes payable [Member]
Debt Instrument [Line Items]
Loan Agreement monthly arrears and interest date	Mar. 01, 2013
Expiration date	Oct. 01, 2015
Notes payable [Member] | Weighted Average [Member]
Debt Instrument [Line Items]
Weighted average annual effective interest rate on notes payable, including amortization of debt discounts and accretion	13.90%
Tranche one [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			10,000,000
Date of Loan and Security Agreement	Oct. 31, 2011
Interest rate				8.95%
Tranche two [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 15,000,000
Line of credit facility remaining amount drawing date	Sep. 30, 2012
Interest rate						9.00%

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CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement Of Stockholders Equity [Abstract]
Issuance of common stock through controlled equity offering facilities	$ 14,734	$ 12,357	$ 18,124
Issuance of common stock through controlled equity offering facilities, issuance costs	442	371	504
Issuance of common stock and warrants in underwritten offering	43,013
Issuance of common stock and warrants in underwritten offering, issuance costs	$ 2,989

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Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Income tax provision	$ 0	$ 0	$ 0
Statutory income tax rate	34.00%
Net valuation allowance increased	14,600,000	12,600,000	13,700,000
Unrecognized tax positions	0	0
Domestic tax authority [Member]
Income Taxes [Line Items]
Net operating loss carry-forwards	364,500,000
Research and development tax credit carry-forwards	8,100,000
Net operating loss carry-forwards expiration	Expire at various dates beginning in 2018
State and local jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carry-forwards	235,800,000
Research and development tax credit carry-forwards	$ 7,200,000
Net operating loss carry-forwards expiration	Begin to expire in 2015

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Loss per Common Share - Computation of Basic and Diluted Loss per Common Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Net loss—basic	$ (1,323)	$ (15,325)	$ (11,781)	$ (14,573)	$ (7,177)	$ (7,607)	$ (8,190)	$ (11,624)	$ (43,002)	$ (34,598)	$ (43,951)
Adjustment for change in fair value of warrant liability									(3,892)
Net loss—diluted	$ (1,323)	$ (15,325)	$ (12,114)	$ (14,573)	$ (8,257)	$ (8,329)	$ (9,336)	$ (11,624)	$ (46,894)	$ (34,598)	$ (43,951)
Denominator:
Weighted-average common shares outstanding—basic	63,041	60,549	60,246	56,313	54,060	51,698	51,630	51,587	60,057	52,249	48,146
Dilutive effect of warrants									1,453
Weighted-average common shares outstanding—diluted	63,041	60,549	61,895	56,313	55,573	53,271	53,268	51,587	61,510	52,249	48,146
Net loss per common share:
Basic	$ (0.02)	$ (0.25)	$ (0.20)	$ (0.26)	$ (0.13)	$ (0.15)	$ (0.16)	$ (0.23)	$ (0.72)	$ (0.66)	$ (0.91)
Diluted	$ (0.02)	$ (0.25)	$ (0.20)	$ (0.26)	$ (0.15)	$ (0.16)	$ (0.18)	$ (0.23)	$ (0.76)	$ (0.66)	$ (0.91)

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Selected Quarterly Financial Data

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data

15. Selected Quarterly Financial Data (unaudited, and in thousands, except per share amounts)

The following table sets forth the Company’s unaudited consolidated financial results for the last eight fiscal quarters.

	Three Months Ended
	Mar. 31,			June 30,			Sep. 30,			Dec. 31,			Mar. 31,			June 30,			Sep. 30,			Dec. 31,
	2014			2014			2014			2014			2013			2013			2013			2013
Revenue	$	1,995		$	1,989		$	854		$	896		$	1,989		$	1,989		$	1,989		$	1,989
Net loss:
Basic	$	(14,573	)	$	(11,781	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(8,190	)	$	(7,607	)	$	(7,177	)
Diluted	$	(14,573	)	$	(12,114	)	$	(15,325	)	$	(1,323	)	$	(11,624	)	$	(9,336	)	$	(8,329	)	$	(8,257	)
Shares used in computing net loss per    common share:
Basic		56,313			60,246			60,549			63,041			51,587			51,630			51,698			54,060
Diluted		56,313			61,895			60,549			63,041			51,587			53,268			53,271			55,573
Net loss per common share:
Basic	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.16	)	$	(0.15	)	$	(0.13	)
Diluted	$	(0.26	)	$	(0.20	)	$	(0.25	)	$	(0.02	)	$	(0.23	)	$	(0.18	)	$	(0.16	)	$	(0.15	)

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Loss per Common Share - Schedule of Potential Common Shares Issuable Pursuant to Outstanding Securities Excluded from Computation of Diluted Loss per Common Share (Detail) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	19,562	17,589	16,647
Warrants to purchase shares of common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	8,978	9,978	10,359
Options to purchase shares of common stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding securities not included in calculations	10,584	7,611	6,288

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Loss per Common Share (Tables)

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Computation of Basic and Diluted Loss per Common Share

The following table sets forth the computation of basic and diluted loss per common share for the periods presented (in thousands, except per share amounts):

	Year Ended December 31,
	2014			2013			2012
Numerator:
Net loss—basic	$	(43,002	)	$	(34,598	)	$	(43,951	)
Adjustment for change in fair value of warrant liability		(3,892	)		—			—
Net loss—diluted	$	(46,894	)	$	(34,598	)	$	(43,951	)
Denominator:
Weighted-average common shares outstanding—basic		60,057			52,249			48,146
Dilutive effect of warrants		1,453			—			—
Weighted-average common shares outstanding—diluted		61,510			52,249			48,146
Net loss per common share:
Basic	$	(0.72	)	$	(0.66	)	$	(0.91	)
Diluted	$	(0.76	)	$	(0.66	)	$	(0.91	)

Schedule of Potential Common Shares Issuable Pursuant to Outstanding Securities Excluded from Computation of Diluted Loss per Common Share

The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted loss per common share because their inclusion would have had an anti-dilutive effect (in thousands):

	As of December 31,
	2014		2013		2012
Warrants to purchase shares of common stock		8,978		9,978		10,359
Options to purchase shares of common stock		10,584		7,611		6,288
Outstanding securities not included in calculations		19,562		17,589		16,647

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CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities
Net loss	$ (43,002)	$ (34,598)	$ (43,951)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	6,219	3,885	2,724
Depreciation and amortization	29	20	31
Amortization of debt discount and debt issuance costs	367	621	400
(Decrease) increase in fair value of warrant liability	(3,892)	(96)	7,509
Foreign exchange gain on marketable securities		(142)	(82)
Gain on sale of property and equipment			(11)
Changes in operating assets and liabilities:
Prepaids and other assets	(43)	489	(98)
Accounts payable	2,224	875	(580)
Accrued clinical expense	(1,638)	(699)	3,079
Accrued compensation	568	254	191
Other accrued liabilities	1,674	(76)	522
Deferred revenue	(5,687)	(7,956)	19,624
Net cash used in operating activities	(43,181)	(37,423)	(10,642)
Cash flows from investing activities
Purchases of property and equipment	(48)
Proceeds from sale of property and equipment			11
Purchases of marketable securities	(42,463)	(26,894)	(67,608)
Proceeds from maturities of marketable securities	45,836	59,110	46,226
Net cash provided by (used in) investing activities	3,325	32,216	(21,371)
Cash flows from financing activities
Proceeds from notes payable, net			14,982
Principal payments on notes payable	(9,356)	(7,182)
Proceeds from issuance of common stock and warrants in underwritten offering, net	40,024
Proceeds from issuance of common stock through controlled equity offering facilities, net	14,292	11,986	17,620
Fair value of warrants issued in connection with royalty agreement			3,122
Proceeds from exercise of warrants, stock options and stock purchase rights	1,961	584	1,918
Net cash provided by financing activities	46,921	5,388	37,642
Net increase (decrease) in cash and cash equivalents	7,065	181	5,629
Cash and cash equivalents at beginning of period	15,121	14,940	9,311
Cash and cash equivalents at end of period	22,186	15,121	14,940
Supplemental disclosure of cash flow information
Interest paid	1,221	2,006	1,165
Supplemental disclosure of non-cash activities
Transfer of fair value of exercised warrants to additional paid-in capital	496	43	1,715
Fair value of warrants issued in connection with notes payable			770
Cashless exercise of warrants	$ 9,337		$ 402

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CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	66,102,000	54,344,000
Common stock, shares outstanding	66,102,000	54,344,000

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Stockholders' Equity

12 Months Ended

Dec. 31, 2014

Equity [Abstract]

Stockholders' Equity

10. Stockholders’ Equity

Preferred Stock

The Company has 10,000,000 shares of authorized preferred stock available for issuance in one or more series. Upon issuance, the Company can determine the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. There were no shares of preferred stock outstanding as of December 31, 2014 and 2013.

Common Stock

Holders of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders of the Company. Subject to the preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably such dividends, if any, as may be declared by the Board of Directors. Under the terms of the Loan Agreement with the Lenders, the Company is precluded from paying cash dividends without the prior written consent of the Lenders.

Underwritten Offering

On March 4, 2014, the Company completed an underwritten offering of 4,650,000 shares of common stock, each with two accompanying warrants to purchase one share of the Company’s common stock at exercise prices of $8.50 (Series A) and $12.00 (Series B) per share, respectively. The purchase price for each share of common stock and two accompanying warrants was $9.25. Gross proceeds from the sale were $43.0 million, and net proceeds were $40.0 million, after deducting the underwriting discount and offering expenses.

The warrants became exercisable on a gross exercise basis upon unblinding of the VALOR trial, which occurred on October 6, 2014. The Series A warrants expired unexercised on December 4, 2014. The Series B warrants will expire on or before the later of 30 days following any final date assigned by the Food and Drug Administration as the Prescription Drug User Fee Act action date for vosaroxin (the “PDUFA date”) and September 4, 2015, but in no event later than March 4, 2016. The common stock and accompanying warrants have both been classified to stockholders’ equity (deficit) in the Company’s balance sheet.

Controlled Equity Offerings

In August 2011, the Company entered into a Controlled Equity Offering^SM sales agreement (the “Sales Agreement”), with Cantor Fitzgerald & Co. (“Cantor”), as agent and/or principal, pursuant to which the Company could issue and sell shares of its common stock having an aggregate gross sales price of up to $20.0 million. In April 2013, the Sales Agreement was amended to provide for an increase of $30.0 million in the aggregate gross sales price under the Sales Agreement. The Company will pay Cantor a commission of 3.0% of the gross proceeds from any common stock sold through the Sales Agreement, as amended.

During the year ended December 31, 2014, the Company sold an aggregate of 5,113,876 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.88 per share for gross proceeds of $14.7 million and net proceeds of $14.3 million, after deducting Cantor’s commission. As of December 31, 2014, $6.8 million of common stock remained available to be sold under this facility.

In January and February 2015, the Company sold an aggregate of 1,579,124 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.75 per share for gross proceeds of $4.3 million and net proceeds of $4.2 million, after deducting Cantor’s commission. As of February 27, 2015, $2.5 million of common stock remained available to be sold under the Sales Agreement, as amended, subject to certain conditions as specified in the agreement.

2010 Offering

In October 2010, the Company completed an underwritten offering, pursuant to which the Company issued an aggregate of 7,357,610 shares of common stock and warrants to purchase 3,678,798 shares of common stock, for aggregate gross proceeds of $15.5 million (the “2010 Offering”). Net proceeds from the sale were $14.2 million, after deducting underwriting discounts and offering expenses. The warrants have an exercise price of $2.52 per share, and expire in October 2015.

The warrants have been classified as a derivative liability on the Company’s balance sheet due to potential cash settlement of the warrants on terms, which do not include a cash limit, and upon the occurrence of certain transactions, as specified in the warrant agreements. At each balance sheet date, the estimated fair value of the outstanding warrants is determined using the Black-Scholes model and recorded to the balance sheet, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss. During the year ended December 31, 2014, warrants to purchase an aggregate of 179,427 shares of common stock that were issued in connection with the 2010 Offering were exercised, resulting in cash proceeds to the Company of $452,000. As of December 31, 2014, warrants to purchase an aggregate of 2,920,051 shares of common stock issued in connection with the 2010 Offering remained outstanding, with an estimated fair value of $3.5 million.

Equity Incentive Plans

The Company grants options to purchase shares of its common stock primarily to: (i) new employees, of which 25% of the shares subject to such options become exercisable on the first anniversary of the vesting commencement date, and 1/48th of the shares subject to such options become exercisable each month over the remainder of the four-year vesting period, (ii) existing employees, of which 1/48th of the shares subject to such options become exercisable each month following the date of grant over a four-year vesting period, (iii) new non-employee members of the board of directors, of which 50% of the shares subject to such options become exercisable on each of the first and second anniversary of the vesting commencement date, and (iv) continuing non-employee members of the board of directors, of which 1/24th of the shares subject to such options become exercisable each month following the date of grant over a two-year vesting period.

On March 15, 2011, the Company’s Board of Directors adopted, and on June 3, 2011, the Company’s stockholders approved, the 2011 Equity Incentive Plan (the “2011 Plan”). The 2011 Plan is intended as the successor to and continuation of the Company’s 1998 Stock Plan, 2001 Stock Plan, 2005 Equity Incentive Award Plan and 2006 Employment Commencement Incentive Plan (collectively, the “Prior Plans”). No additional stock awards will be granted under the Prior Plans.

The Company initially reserved a total of 6,041,856 shares of common stock for issuance under the 2011 Plan, which is the sum of (i) the 539,803 shares remaining available as of the Effective Date under the Prior Plans, (ii) an additional 4,400,000 new shares, and (iii) that portion of the 1,102,053 shares underlying stock options granted and currently outstanding under the Prior Plans that expire or terminate for any reason prior to exercise or settlement or that are forfeited because of the failure to meet a contingency or condition required to vest such shares.

The number of shares of common stock available for issuance under the 2011 Plan automatically increases on January 1st of each year for a period of 10 years commencing on January 1, 2012 by an amount equal to: (i) 4.0% of the Company’s outstanding shares of common stock on December 31st of the preceding calendar year, or (ii) a lesser amount determined by the Board of Directors. On January 1, 2014 and 2013, in accordance with the above, the number of shares of common stock available for issuance under the 2011 Plan was increased by 2,173,764 and 2,062,609 shares, respectively.

During the year ended December 31, 2014, options to purchase 3,840,500 shares of the Company’s common stock were granted under the 2011 Plan. As of December 31, 2014, there were 672,273 shares available for future grants under the 2011 Plan.

Employee Stock Purchase Plans

On March 5, 2011, the Company’s Board of Directors adopted, and on June 3, 2011, the Company’s stockholders approved, the 2011 Employee Stock Purchase Plan (the “2011 ESPP”). The 2011 ESPP is intended as the successor to the Company’s 2005 Employee Stock Purchase Plan, which was terminated on June 3, 2011.

The 2011 ESPP permits eligible employees to purchase common stock at a discount through payroll deductions during defined offering periods. Eligible employees can purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the common stock at (i) the beginning of a 12-month offering period, or (ii) at the end of one of the two related 6-month purchase periods. No participant in the 2011 ESPP may be issued or transferred shares of common stock valued at more than $25,000 per calendar year. The initial offering under the 2011 ESPP commenced on June 13, 2011 and ended on May 31, 2012. Subsequent 12-month offerings commenced or will commence on or around June 1st of each year.

The Company initially reserved a total of 500,000 shares of common stock for issuance under the 2011 ESPP. The number of shares of common stock available for issuance under the 2011 ESPP automatically increases on January 1st of each year for a period of 10 years commencing on January 1, 2012 by an amount equal to: (i) 1.0% of the Company’s outstanding shares of common stock on December 31st of the preceding calendar year, or (ii) a lesser amount determined by the Board of Directors. On January 1, 2014 and 2013, in accordance with the above, the number of shares of common stock available for issuance under the 2011 ESPP was increased by 271,720 and nil shares, respectively.

A total of 99,049 shares were issued under the 2011 ESPP during the year ended December 31, 2014. As of December 31, 2014, there were 431,672 shares available for future issuance under the ESPP.

Warrants

Warrants to purchase shares of the Company’s common stock outstanding as of December 31, 2014 were as follows (in thousands, except per share amounts):

			Exercise Price
Date Issued	Shares		Per Share		Expiration
August 2005		14	$	54.60	August 2015
October 2010		2,920	$	2.52	October 2015
March 2014		4,650	$	12.00	March 2016
April 2009		2,876	$	1.32	April 2016
October 2009		1,438	$	1.32	October 2016
Total warrants outstanding and exercisable		11,898

Reserved Shares

Shares of the Company’s common stock reserved for future issuance as of December 31, 2014 were as follows (in thousands):

	Shares
	Available				Total
	for Future		Outstanding		Shares
	Grant		Securities		Reserved
Warrants		—		11,898		11,898
Stock option plans		672		10,584		11,256
Employee stock purchase plan		432		—		432
Total reserved shares of common stock		1,104		22,482		23,586

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Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 27, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	SNSS
Entity Registrant Name	SUNESIS PHARMACEUTICALS INC
Entity Central Index Key	0001061027
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		67,739,771
Entity Public Float			$ 263,889,528

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Stock-Based Compensation

12 Months Ended

Dec. 31, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11. Stock-Based Compensation

Overview

Employee stock-based compensation expense is calculated based on the grant-date fair value of awards ultimately expected to vest, reduced for estimated forfeitures, and is recorded on a straight-line basis over the vesting period of the awards. Forfeitures are estimated at the time of grant, based on historical option cancellation information, and revised in subsequent periods if actual forfeitures differ from those estimates. The following table summarizes stock-based compensation expense related to the Company’s stock-based awards for the periods indicated (in thousands):

	Year ended December 31,
	2014		2013		2012
Research and development	$	2,201	$	1,598	$	1,030
General and administrative		3,681		1,983		1,372
Employee stock-based compensation expense		5,882		3,581		2,402
Non-employee stock-based compensation expense		337		304		322
Total stock-based compensation expense	$	6,219	$	3,885	$	2,724

Fair Value of Awards

The Company determines the fair value of stock-based awards on the grant date using the Black-Scholes model, which is impacted by the Company’s stock price, as well as assumptions regarding a number of highly subjective variables. The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model, and resulting weighted-average and total estimated grant date fair values of employee stock options granted during the periods indicated:

	Year Ended December 31,
	2014			2013			2012
Assumptions:
Expected term (years)		5.2			4.7			5.4
Expected volatility		88.1	%		90.0	%		88.7	%
Risk-free interest rate		1.7	%		1.0	%		1.1	%
Expected dividend yield		0.0	%		0.0	%		0.0	%
Fair value:
Weighted-average estimated grant date fair value per    share	$	3.18		$	3.63		$	1.46
Options granted to employees (in thousands)		3,676			1,785			2,310
Total estimated grant date fair value (in thousands)	$	11,704		$	6,472		$	3,377

The estimated fair value of stock options that vested in the years ended December 31, 2014, 2013 and 2012, was $2.6 million, $3.4 million and $2.1 million, respectively. The Company based its assumptions for the expected term on historical cancellation and exercise data, and the contractual term and vesting terms of the awards. Expected volatility is based on historical volatility of the Company’s common stock, as well as that for a mature peer group of companies in the same industry. The Company does not anticipate paying any cash dividends in the foreseeable future, and therefore uses an expected dividend yield of zero.

Option Plan Activity

The following table summarizes stock option activity for the Company’s stock option plans in the periods presented (in thousands, except per share amounts):

				Weighted		Weighted
				Average		Average
	Number			Exercise		Remaining		Aggregate
	of			Price Per		Contractual		Intrinsic
	Shares			Share		Term (Years)		Value
Outstanding as of December 31, 2013		7,611		$	3.61
Options granted		3,840		$	4.54
Options exercised		(565	)	$	2.17
Options forfeited or expired		(302	)	$	7.13
Outstanding as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Vested and expected to vest as of December 31, 2014		10,584		$	3.93		7.63	$	3,885
Exercisable as of December 31, 2014		5,701		$	3.86		6.57	$	2,075

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (i.e., the difference between the Company’s closing stock price on the last trading day of the period and the exercise price, multiplied by the number of in-the-money options) that would have been received by option holders if they had exercised all their options on December 31, 2014.

The intrinsic value of options exercised during the years ended December 31, 2014, 2013 and 2012 was $2.7 million, $0.3 million and $0.2 million, respectively. As the Company believes it is more likely than not that no stock option related tax benefits will be realized, the Company does not record any net tax benefits related to exercised options.

Total estimated unrecognized stock-based compensation cost related to unvested stock options was $12.2 million as of December 31, 2014, which is expected to be recognized over the respective vesting terms of each award. The weighted average term of the unrecognized stock-based compensation expense is 2.6 years.

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CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue:
License and other revenue	$ 5,734	$ 7,956	$ 3,754
Total revenues	5,734	7,956	3,754
Operating expenses:
Research and development	27,665	28,891	29,185
General and administrative	23,112	10,838	9,175
Total operating expenses	50,777	39,729	38,360
Loss from operations	(45,043)	(31,773)	(34,606)
Interest expense	(1,719)	(2,917)	(1,855)
Other income (expense), net	3,760	92	(7,490)
Net loss	(43,002)	(34,598)	(43,951)
Unrealized (loss) gain on available-for-sale securities	(4)	(41)	19
Comprehensive loss	(43,006)	(34,639)	(43,932)
Net loss:
Basic	(43,002)	(34,598)	(43,951)
Diluted	$ (46,894)	$ (34,598)	$ (43,951)
Shares used in computing net loss per common share:
Basic	60,057	52,249	48,146
Diluted	61,510	52,249	48,146
Net loss per common share:
Basic	$ (0.72)	$ (0.66)	$ (0.91)
Diluted	$ (0.76)	$ (0.66)	$ (0.91)

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Other Accrued Liabilities

12 Months Ended

Dec. 31, 2014

Payables And Accruals [Abstract]

Other Accrued Liabilities

5. Other Accrued Liabilities

Other accrued liabilities as of December 31 were as follows (in thousands):

	2014		2013
Accrued outside services	$	2,656	$	1,249
Accrued professional services		355		263
Other accruals		76		133
Total other accrued liabilities	$	3,087	$	1,645

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Financial Instruments

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Financial Instruments

4. Financial Instruments

Financial Assets

The following tables summarize the estimated fair value of the Company’s financial assets measured on a recurring basis as of the dates indicated, which were comprised solely of available-for-sale marketable securities with remaining contractual maturities of one year or less (in thousands):

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2014	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	9,287		$	—	$	—		$	9,287
U.S. certificates of deposit	Level 1		6,360			—		—			6,360
U.S. corporate debt obligations	Level 2		11,789			—		(7	)		11,782
U.S. commercial paper	Level 2		2,898			—		—			2,898
Total available-for-sale securities			30,334			—		(7	)		30,327
Less amounts classified as cash equivalents			(9,532	)		—		—			(9,532	)
Amounts classified as marketable securities		$	20,802		$	—	$	(7	)	$	20,795

					Gross		Gross
	Valuation	Amortized			Unrealized		Unrealized			Estimated Fair
December 31, 2013	Input Level	Cost			Gains		Losses			Value
Money market funds	Level 1	$	6,282		$	—	$	—		$	6,282
U.S. corporate debt obligations	Level 2		13,509			—		(4	)		13,505
U.S. commercial paper	Level 2		8,396			3		—			8,399
Foreign corporate debt obligations	Level 2		2,571			—		(2	)		2,569
Total available-for-sale securities			30,758			3		(6	)		30,755
Less amounts classified as cash equivalents			(6,583	)		—		—			(6,583	)
Amounts classified as marketable securities		$	24,175		$	3	$	(6	)	$	24,172

The following table summarizes the available-for-sale securities that were in an unrealized loss position as of December 31, 2014, each having been in such a position for less than 12 months, and none deemed to be other-than-temporarily impaired (in thousands):

	Gross
	Unrealized		Estimated Fair
December 31, 2014	Losses		Value
U.S. corporate debt obligations	$	7	$	11,782
Total available-for-sale securities in an unrealized loss    position	$	7	$	11,782

No significant facts or circumstances have arisen to indicate that there has been any deterioration in the creditworthiness of the issuers of these securities. The gross unrealized losses are not considered to be significant and have generally been for relatively short durations. The Company does not intend to sell these securities before maturity and it is not likely that they will need to be sold prior to the recovery of their amortized cost basis. There were no sales of available-for-sale debt securities in the years ended December 31, 2014, 2013 and 2012.

Financial Liabilities

The following table summarizes the inputs and assumptions and estimated fair value of the Company’s financial liabilities measured on a recurring basis as of the dates indicated, which were comprised solely of a liability for warrants issued in connection with an underwritten equity offering completed in 2010 (see Note 10):

	December 31,			December 31,
	2014			2013
Inputs and assumptions:
Fair market value of Company’s common stock	$	2.55		$	4.74
Exercise price	$	2.52		$	2.52
Expected term (years)		0.8			1.8
Expected volatility		144.9	%		60.8	%
Risk-free interest rate		0.2	%		0.3	%
Expected dividend yield		0.0	%		0.0	%
Fair value:
Estimated fair value per warrant share	$	1.21		$	2.56
Shares underlying outstanding warrants classified as    liabilities (in thousands)		2,920			3,099
Total estimated fair value of outstanding warrants    (in thousands)	$	3,543		$	7,931

The warrants have been classified as a liability on the Company’s balance sheet due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements. At each balance sheet date, the estimated fair value of the outstanding warrants is determined using the Black-Scholes model and recorded to the balance sheet, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss, and the fair value of warrant exercises transferred to additional paid-in capital. During the year ended December 31, 2014, warrants to purchase 179,427 shares of common stock issued in connection with the 2010 Offering were exercised, resulting in cash proceeds to the Company of $452,000.

The Black-Scholes model requires Level 3 inputs such as the expected term of the warrants and share price volatility. These inputs are subjective and generally require significant analysis and judgment to develop. Any changes in these inputs could result in a significantly higher or lower fair value measurement.

The following table summarizes the changes in the fair value of the Company’s Level 3 financial liabilities for the periods indicated (in thousands):

	Warrant
	Liability
Balance as of December 31, 2012	$	8,070
Change in fair value of warrant liability		(96	)
Exercise of warrants		(43	)
Balance as of December 31, 2013		7,931
Change in fair value of warrant liability		(3,892	)
Exercise of warrants		(496	)
Balance as of December 31, 2014	$	3,543

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Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”).

Recent Accounting Pronouncements

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), that will supersede most existing revenue recognition guidance under US GAAP. The core principle of the guidance is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. Entities can choose to apply the standard using either the full retrospective approach or a modified retrospective approach. Entities electing the full retrospective adoption will apply the standard to each period presented in the financial statements. This means that entities will have to apply the new guidance as if it had been in effect since the inception of all its contracts with customers presented in the financial statements. Entities that elect the modified retrospective approach will apply the guidance retrospectively only to the most current period presented in the financial statements. This means that entities will have to recognize the cumulative effect of initially applying the new standard as an adjustment to the opening balance of retained earnings at the date of initial application. The new revenue standard will be applied to contracts that are in progress at the date of initial application. The standard will be effective for annual and interim periods beginning after December 15, 2016. The Company has yet to evaluate which adoption method it plans to use or the potential effect of the new standard on its consolidated financial statements.

In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”), which will require a reporting entity to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the reporting entity’s ability to continue as a going concern within one year after the date the financial statements are issued and provide related disclosures. The standard will be effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The Company has yet to evaluate the potential effect of the new standard on its consolidated financial statements.

Principles of Consolidation

Principles of Consolidation

Segment Reporting

Segment Reporting

Management has determined that the Company operates as a single reportable segment.

Significant Estimates and Judgments

Significant Estimates and Judgments

Cash Equivalents and Marketable Securities

Cash Equivalents and Marketable Securities

The Company considers all highly liquid securities with original maturities of three months or less from the date of purchase to be cash equivalents, which generally consist of money market funds and corporate debt securities. Marketable securities consist of securities with original maturities of greater than three months, which may include U.S. and European government obligations and corporate debt securities.

Management determines the appropriate classification of securities at the time of purchase. The Company generally classifies its entire investment portfolio as available-for-sale. The Company views its available-for-sale portfolio as available for use in current operations. Accordingly, the Company classifies all investments as short-term, even though the stated maturity may be more than one year from the current balance sheet date. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported in accumulated other comprehensive income (loss), which is a separate component of stockholders’ equity (deficit).

The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in other income (expense), net in the statements of operations and comprehensive loss. Realized gains and losses and declines in value judged to be other-than-temporary on available-for-sale securities, if any, are also recorded to other income (expense), net. The cost of securities sold is based on the specific-identification method.

Invoices for certain services provided to the Company are denominated in foreign currencies. To manage the risk of future movements in foreign exchange rates that would affect such amounts, the Company may purchase certain European currencies or highly-rated investments denominated in those currencies, subject to similar criteria as for other investments defined in the Company’s investment policy. There is no guarantee that the related gains and losses will substantially offset each other, and the Company may be subject to significant exchange gains or losses as currencies fluctuate from quarter to quarter. To date, the Company has purchased Euros and Euro-denominated obligations of foreign governments and corporate debt. As of December 31, 2014 and December 31, 2013, the Company held investments denominated in Euros with an aggregate fair value of $0 and $2.6 million, respectively. Any cash, cash equivalent and short-term investment balances denominated in foreign currencies are recorded at their fair value based on the current exchange rate as of each balance sheet date. The resulting exchange gains or losses and those from amounts payable for services originally denominated in foreign currencies are both recorded in other income (expense), net in the statements of operations and comprehensive loss.

Fair Value Measurements

Fair Value Measurements

The Company measures cash equivalents, marketable securities and warrant liabilities at fair value on a recurring basis using the following hierarchy to prioritize valuation inputs, in accordance with applicable GAAP:

Level 1 -	quoted prices (unadjusted) in active markets for identical assets and liabilities that can be accessed at the measurement date
Level 2 -	inputs other than quoted prices included within Level 1 that are observable, either directly or indirectly
Level 3 -	unobservable inputs

The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets.

The fair value of the Company’s liability for warrants issued in connection with an underwritten offering completed in October 2010 (the “2010 Offering”) is determined using the Black-Scholes model, which requires inputs such as the expected term of the warrants, share price volatility, expected dividend yield and risk-free interest rate. As some of these inputs are unobservable, and require significant analysis and judgment to measure, these variables are classified as Level 3.

The carrying amounts of the Company’s financial instruments, including cash, prepayments, accounts payable, accrued liabilities, deferred revenue and notes payable approximated their fair value as of December 31, 2014 and December 31, 2013.

Property and Equipment

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is determined using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the term of the lease.

Accounting for Royalty Agreement

Accounting for Royalty Agreement

The payment of $25.0 million by RPI under the Royalty Agreement (see Note 6) is non-refundable, and no revenue participation right payments will be made unless vosaroxin is commercialized. Accordingly, the payment received from RPI is being accounted for as a payment for the Company to use commercially reasonable efforts to commercialize vosaroxin. Therefore, the amount is to be deferred and recognized as revenue over the projected performance period under the agreement. The payment, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period. The fair value of the warrants was recorded to additional paid-in capital.

Accounting for Notes Payable

Accounting for Notes Payable

The accounting for certain fees and expenses related to the Loan Agreement (see Note 8) is as follows. The facility fee is being accounted for as a debt discount and classified within notes payable on the Company’s balance sheet. The fair value of the warrants issued in connection with the Loan Agreement have been recorded as a debt discount within notes payable and an increase to additional paid-in capital on the Company’s balance sheet. The debt discount is being amortized as interest expense over the term of the loan using the effective interest method. The final payment is being accreted as interest expense over the term of the loans using the effective interest method. The legal fees are being accounted for as deferred debt issuance costs within assets on the Company’s balance sheet and are being amortized as other income (expense), net over the term of the loans using the effective interest method.

Accounting for Equity Financing

Accounting for Equity Financing

In October 2010, the Company completed the 2010 Offering (see Note 10), in which the Company sold its common stock and warrants to purchase its common stock for aggregate gross proceeds of $15.5 million. Due to the potential for the warrants to be settled in cash upon the occurrence of certain transactions specified in the warrant agreements, the warrants are being accounted for as a derivative liability as opposed to permanent equity. Outstanding warrants under this arrangement are revalued to their fair value each period end, with the change in fair value recorded to other income (expense), net in the statements of operations and comprehensive loss.

Revenue Recognition

Revenue Recognition

Revenue arrangements with multiple deliverables are accounted for in accordance with the Financial Accounting Standards Board Accounting Standards Codification, Subtopic 605-25, Multiple-Element Arrangements (“ASC 605-25”). Under ASC 605-25, revenue arrangements with multiple deliverables are divided into separate units of accounting based on whether certain criteria are met, including whether the delivered item has stand-alone value to the customer. Consideration is allocated among the separate units of accounting based on their respective fair value, and the applicable revenue recognition is applied to each of the separate units.

Non-refundable fees where the Company has no continuing performance obligations are recognized as revenues when collection is reasonably assured. In situations where continuing performance obligations exist, non-refundable fees are deferred and recognized ratably over the projected performance period.

Milestone payments from license or collaboration agreements which are substantive and at risk at the time the agreement is executed are recognized upon completion of the applicable milestone event. Royalty revenues, if any, will be recognized based on reported product sales by third-party licensees. Research funding from any future agreement will be recognized as the related research services are performed.

Research and Development

Research and Development

Research and development expense consists primarily of: (a) clinical trial costs, which include payments for work performed by contract research organizations (“CROs”), clinical trial sites, labs and other clinical service providers, and for drug packaging, storage and distribution; (b) drug manufacturing costs, which include costs for producing drug substance and drug product, and for stability and other testing; (c) personnel costs for related permanent and temporary employees; (d) other outside services and consulting costs; and (e) payments under license agreements. All research and development costs are expensed as they are incurred.

Clinical Trial Accounting

Clinical Trial Accounting

The Company records accruals for estimated clinical trial costs, which include payments for work performed by CROs and participating clinical trial sites. These costs are generally a significant component of research and development expense. Costs incurred for setting up clinical trial sites for participation in trials are generally non-refundable, and are expensed as incurred, with any refundable advances related to enrollment of the first patient recorded as prepayments and assessed for recoverability on a quarterly basis. Costs related to patient enrollment are accrued as patients progress through the clinical trial, including amortization of any first-patient prepayments. This amortization generally matches when the related services are rendered, however, these cost estimates may or may not match the actual costs incurred by the CROs or clinical trial sites, and if the Company has incomplete or inaccurate information, the clinical trial accruals may not be accurate. The difference between accrued expenses based on the Company’s estimates and actual expenses have not been significant to date.

Stock-Based Compensation

Stock-Based Compensation

The Company grants options to purchase common stock to its employees, directors and consultants under its stock option plans. Under the Company’s Employee Stock Purchase Plan, eligible employees can also purchase shares of the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock at the beginning of a 12-month offering period or at the end of one of the two related six-month purchase periods.

The Company values these share-based awards using the Black-Scholes option valuation model (the “Black-Scholes model”). The determination of fair value of share-based payment awards on the date of grant using the Black-Scholes model is affected by the Company’s stock price as well as assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected stock price volatility over the term of the awards and actual and projected employee stock option exercise behaviors and related estimated forfeitures.

Foreign Currency

Foreign Currency

Transactions that are denominated in a foreign currency are translated into U.S. dollars at the current exchange rate on the transaction date. Any foreign currency-denominated monetary assets and liabilities are subsequently remeasured at current exchange rates as of each balance sheet date, with gains or losses on foreign exchange recognized in other income (expense), net in the statements of operations and comprehensive loss.

Income Taxes

Income Taxes

The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the differences between the tax basis of assets and liabilities and their basis for financial reporting. Deferred tax assets or liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which temporary differences are expected to be recovered or settled. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company’s policy is to recognize interest charges and penalties in other income (expense), net in the statements of operations and comprehensive loss.

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Income Taxes

12 Months Ended

Dec. 31, 2014

Income Tax Disclosure [Abstract]

Income Taxes

12. Income Taxes

Loss before the provision for income taxes consisted of the following (in thousands):

	Year Ended December 31,
	2014			2013			2012
U.S. operations	$	(32,696	)	$	(29,963	)	$	(43,951	)
Foreign operations		(10,306	)		(4,635	)		—
Loss before provision for income taxes	$	(43,002	)	$	(34,598	)	$	(43,951	)

No provision for income taxes was recorded in the periods presented due to tax losses incurred in each period. The income tax provision differs from the amount computed by applying the statutory income tax rate of 34% to pre-tax loss as follows (in thousands):

	Year Ended December 31,
	2014			2013			2012
Tax at statutory rate	$	(14,620	)	$	(11,763	)	$	(14,943	)
Current year net operating losses and temporary differences    for which no tax benefit is recognized		14,104			12,457			5,351
Foreign tax rate differential		3,504			1,499			—
Deferred revenue		(1,934	)		(2,706	)		6,672
Change in fair value of warrant liability		(1,313	)		(16	)		2,570
Other permanent differences		259			529			350
Provision for income taxes	$	—		$	—		$	—

Deferred income taxes reflect the net tax effects of loss and credit carry-forwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands):

	December 31,
	2014			2013
Deferred tax assets:
Federal and state net operating loss carry-forwards	$	138,066		$	123,490
Federal and state research credit carry-forwards		12,964			12,064
Capitalized research costs		5,199			5,119
Deferred revenue		2,394			4,668
Stock-based compensation		4,358			3,212
Property and equipment		129			133
Accrued liabilities		481			341
Gross deferred tax assets		163,591			149,027
Valuation allowance		(163,591	)		(149,027	)
Net deferred tax assets	$	—		$	—

Realization of the deferred tax assets is dependent upon future taxable income, if any, the amount and timing of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The net valuation allowance increased by approximately $14.6 million, $12.6 million and $13.7 million during the years ended December 31, 2014, 2013 and 2012, respectively.

As of December 31, 2014, the Company had federal net operating loss carry-forwards of $364.5 million and federal research and development tax credit carry-forwards of $8.1 million. If not utilized, the federal net operating loss and tax credit carry-forwards will expire at various dates beginning in 2018. As of December 31, 2014, the Company had state net operating loss carry-forwards of $235.8 million, which begin to expire in 2015, and state research and development tax credit carry-forwards of $7.2 million, which do not expire.

Utilization of these net operating loss and tax credits carry-forwards may be subject to a substantial annual limitation due to the ownership change rules under Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”). The limitations are applicable if an “ownership change,” as defined in the Code, is deemed to have occurred or occurs in the future. The annual limitation may result in the expiration of net operating loss and credit carry-forwards before they can be utilized.

The Company recognizes the financial statement effect of tax positions when it is more likely than not that the tax positions will be sustained upon examination by the appropriate taxing authorities. As of December 31, 2014 and 2013, the Company had no unrecognized tax positions.

The Company files U.S. federal and California tax returns.  The Company’s wholly owned subsidiaries, Sunesis Europe Limited and Sunesis Pharmaceuticals (Bermuda) Ltd., are currently not required to file tax returns. To date, neither the Company nor any of its subsidiaries have been audited by the Internal Revenue Service, any state income tax authority or tax authority in the related jurisdictions. Due to net operating loss carry-forwards, substantially all of the Company’s tax years remain open to federal tax examination.

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Notes Payable

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Notes Payable

8. Notes Payable

In October 2011, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Oxford Finance LLC, Silicon Valley Bank and Horizon Technology Finance Corporation (collectively, the “Lenders”), under which the Company could borrow up to $25.0 million in two tranches (the “Loan Facility”). The first tranche of $10.0 million was funded upon closing of the transaction in October 2011, and the second tranche of $15.0 million was drawn by the Company in September 2012. In connection with the Loan Agreement, the Lenders were granted a perfected first priority security interest in substantially all of the Company’s assets, other than intellectual property.

The interest rates for the first and second tranche are 8.95% and 9.00% per annum, respectively. Payments under the Loan Agreement are monthly in arrears and were interest-only until February 1, 2013, followed by 32 equal monthly payments of principal and interest from March 1, 2013 to the scheduled maturity date of October 1, 2015. In addition, a final payment equal to $937,500 will be due on October 1, 2015, or such earlier date as specified in the Loan Agreement. The weighted average annual effective interest rate on the notes payable, including the amortization of the debt discounts and accretion of the final payment, is 13.9%.

Aggregate future minimum payments due under the Loan Facility as of December 31, 2014 were as follows (in thousands):

Year ending December 31,	Total
2015	$	8,814
Total minimum payments		8,814
Less amount representing interest		(352	)
Notes payable, gross		8,462
Unamortized discount on notes payable		(84	)
Accretion of final payment		879
Notes payable, balance		9,257
Less current portion of notes payable		(9,257	)
Non-current portion of notes payable	$	—

On February 27, 2015, the Company entered into a third amendment (the “Amendment”), to the Loan Agreement with the Lenders. The Amendment modifies the loan repayment terms to be interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. See Note 14 for further details.

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Income Taxes - Income Tax Provision Amount Computed by Applying Statutory Income Tax Rate (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Tax at statutory rate	$ (14,620,000)	$ (11,763,000)	$ (14,943,000)
Current year net operating losses and temporary differences for which no tax benefit is recognized	14,104,000	12,457,000	5,351,000
Foreign tax rate differential	3,504,000	1,499,000
Deferred revenue	(1,934,000)	(2,706,000)	6,672,000
Change in fair value of warrant liability	(1,313,000)	(16,000)	2,570,000
Other permanent differences	259,000	529,000	350,000
Provision for income taxes	$ 0	$ 0	$ 0

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Royalty Agreement

12 Months Ended

Dec. 31, 2014

Deferred Revenue Disclosure [Abstract]

Royalty Agreement

6. Royalty Agreement

In March 2012, the Company entered into a Revenue Participation Agreement (the “Royalty Agreement”), with RPI Finance Trust (“RPI”), an entity related to Royalty Pharma. In September 2012, pursuant to the provisions of the Royalty Agreement, RPI made a $25.0 million cash payment to the Company. In conjunction with the Royalty Agreement, we issued two five-year warrants to RPI, each to purchase 1,000,000 shares of our common stock, at exercise prices of $3.48 and $4.64 per share, respectively. Both warrants were net exercised in 2014, resulting in an aggregate issuance of 777,107 shares of common stock. The payment of $25.0 million, less $3.1 million representing the fair value of the warrants granted under the arrangement, was initially classified as deferred revenue and is being amortized to revenue over the related performance period.

Based on the results of the VALOR trial and the Company’s plans to meet with European regulatory authorities in preparation for the filing of an MAA with the EMA in the second half of 2015 and to continue discussions with the FDA to determine a potential regulatory path forward in the United States, as discussed in Note 1, the Company extended the end date of the estimated performance period through which the balance of deferred revenue will be amortized from June 30, 2015 to September 30, 2016. As a result, the quarterly amortization was adjusted to $0.9 million per quarter, commencing with the quarter ended September 30, 2014, from the previous amortization rate of $2.0 million per quarter.

Revenue participation right payments will be made to RPI when and if vosaroxin is commercialized, at a rate of 6.75% of net sales of vosaroxin, on a product-by-product and country-by-country basis world-wide through the later of: (a) the expiration of the last to expire of certain specifically identified patents; (b) 10 years from the date of first commercial sale of such product in such country; or (c) the expiration of all applicable periods of data, market or other regulatory exclusivity in such country with respect to such product.

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License Agreements

12 Months Ended

Dec. 31, 2014

Goodwill And Intangible Assets Disclosure [Abstract]

License Agreements

7. License Agreements

Overview

In August 2004, the Company entered into a collaboration agreement with Biogen Idec MA, Inc. (“Biogen Idec”) to discover, develop and commercialize small molecule inhibitors of the human protein Raf kinase, including family members Raf-1, A-Raf, B-Raf and C-Raf (collectively “Raf”) and up to five additional targets that play a role in oncology and immunology indications (the “Biogen Idec OCA”). In connection with the Company’s June 2008 restructuring, the parties agreed to terminate the research obligations and related funding as of June 30, 2008.

In March 2011, as part of a series of agreements among the Company, Biogen Idec and Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, (“Millennium”), the Company entered into: (a) an amended and restated collaboration agreement with Biogen Idec (the “Biogen Idec 1st ARCA”); (b) a license agreement with Millennium (the “Millennium Agreement”); and (c) a termination and transition agreement among the Company, Biogen Idec and Millennium (the “Termination and Transition Agreement”).

The Termination and Transition Agreement provided for (a) the termination of Biogen Idec’s exclusive rights under the Biogen Idec OCA to all discovery programs under such agreement other than for small molecule inhibitors of the human protein Bruton’s tyrosine kinase (“BTK”); (b) the permitted assignment to Millennium of all related Company collaboration assets and rights to Raf kinase and the human protein phosphoinositide-dependent kinase-1 (“PDK1”); and (c) the payment of $4.0 million upfront from Millennium to the Company, which was recorded as revenue in March 2011.

Biogen Idec

The Biogen Idec 1st ARCA amended and restated the Biogen Idec OCA, to provide for the discovery, development and commercialization of small molecule BTK inhibitors. Under this agreement, the Company no longer has research obligations, but licenses granted to Biogen Idec with respect to the research collaboration under the Biogen Idec OCA (other than the licenses transferred to Millennium under the Millennium Agreement) remain in effect.

In June 2012, the Company received an event-based payment of $1.5 million from Biogen Idec for the advancement of pre-clinical work in connection with the Biogen Idec 1st ARCA. Under this agreement, the Company is eligible to receive up to an additional $58.5 million in pre-commercialization event-based payments related to the development by Biogen Idec of the first two indications for licensed products against the BTK target. The Company is also eligible to receive royalty payments depending on related product sales, if any.

In December 2013, the Company entered into a second amended and restated collaboration agreement with Biogen Idec (the “Biogen Idec 2nd ARCA”), to provide the Company with an exclusive worldwide license to develop, manufacture and commercialize SNS-062, a BTK inhibitor synthesized under the Biogen Idec 1st ARCA, solely for oncology indications. The Company may be required to make a $2.5 million milestone payment depending on its development of SNS-062 and royalty payments depending on related product sales of SNS-062. All other of Sunesis’ rights and obligations contained in the Biogen Idec 1st ARCA remain unchanged, except that potential future royalty payments to Sunesis were reduced to equal those amounts due to Biogen Idec for potential future sales of SNS-062.

Millennium

Under the Millennium Agreement, the Company granted exclusive licenses to products against two oncology targets originally developed under the Biogen Idec OCA, Raf and PDK1, under substantially the same terms as under the Biogen Idec OCA.

In January 2014, the Company entered into an amended and restated license agreement with Millennium (the “Amended Millennium Agreement”), to provide the Company with an exclusive worldwide license to develop and commercialize preclinical inhibitors of PDK1. In connection with the execution of the Amended Millennium Agreement, the Company paid an upfront fee and may be required to make up to $9.2 million in pre-commercialization milestone payments depending on its development of PDK1 inhibitors and royalty payments depending on related product sales, if any.

With respect to the Raf target product rights that were originally licensed to Millennium under the Millennium Agreement, the Company may in the future receive up to $57.5 million in pre-commercialization event-based payments related to the development by Millennium of the first two indications for each of the licensed products directed against the Raf target and royalty payments depending on related product sales. Millennium is currently conducting a Phase 1 clinical study of an oral investigative drug, MLN2480, which is licensed to them under the Amended Millennium Agreement.

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Commitments and Contingencies

12 Months Ended

Dec. 31, 2014

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

Commitments

The Company’s operating lease obligations as of December 31, 2014 relate solely to the leasing of office space in a building at 395 Oyster Point Boulevard in South San Francisco, California, which is currently the Company’s headquarters. In January 2014, a lease for 15,378 square feet was entered into with an expiry date of April 30, 2015. In June 2014, the lease was amended to extend the expiration date to June 30, 2015, and to add 6,105 square feet of additional office space within the same building, and in January 2015, the lease was further amended to extend the expiration date to December 31, 2015. The amended lease also includes an option to extend the lease for an additional six months, at a predetermined price, if exercised within a certain period.

Aggregate non-cancelable future minimum rental payments under the operating lease as of December 31, 2014 were as follows (in thousands):

Year Ending December 31,	Payments
2015	$	247
Total rental payments	$	247

The Company recognizes rent expense on a straight-line basis. The Company recorded rent expense of $0.4 million, $0.3 million and $0.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Contingencies

From time to time, the Company may be involved in legal proceedings, as well as demands, claims and threatened litigation, which arise in the normal course of its business or otherwise. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on the Company’s results of operations and financial condition. Regardless of outcome, litigation can have an adverse impact on the Company because of the defense costs, diversion of management resources and other factors. The Company is not currently involved in any material legal proceedings.

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Selected Quarterly Financial Data - Schedule of Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenue	$ 896	$ 854	$ 1,989	$ 1,995	$ 1,989	$ 1,989	$ 1,989	$ 1,989	$ 5,734	$ 7,956	$ 3,754
Net loss:
Basic	(1,323)	(15,325)	(11,781)	(14,573)	(7,177)	(7,607)	(8,190)	(11,624)	(43,002)	(34,598)	(43,951)
Diluted	$ (1,323)	$ (15,325)	$ (12,114)	$ (14,573)	$ (8,257)	$ (8,329)	$ (9,336)	$ (11,624)	$ (46,894)	$ (34,598)	$ (43,951)
Denominator:
Basic	63,041	60,549	60,246	56,313	54,060	51,698	51,630	51,587	60,057	52,249	48,146
Diluted	63,041	60,549	61,895	56,313	55,573	53,271	53,268	51,587	61,510	52,249	48,146
Net loss per common share:
Basic	$ (0.02)	$ (0.25)	$ (0.20)	$ (0.26)	$ (0.13)	$ (0.15)	$ (0.16)	$ (0.23)	$ (0.72)	$ (0.66)	$ (0.91)
Diluted	$ (0.02)	$ (0.25)	$ (0.20)	$ (0.26)	$ (0.15)	$ (0.16)	$ (0.18)	$ (0.23)	$ (0.76)	$ (0.66)	$ (0.91)

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Subsequent Events - Additional information (Detail) (USD $)	12 Months Ended			0 Months Ended	2 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 27, 2015 Loan	Feb. 28, 2015	Jan. 31, 2015
Subsequent Event [Line Items]
Line of credit facility final payment	$ 937,500
Proceeds from issuance of common stock through controlled equity offering facilities, net	14,292,000	11,986,000	17,620,000
Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Price per common share including accompanying warrants	$ 2.88
Common stock, shares sold	5,113,876
Proceeds from issuance of common shares and warrants in offering, gross	14,700,000
Proceeds from issuance of common stock through controlled equity offering facilities, net	14,300,000
Further Amended Operating Lease [Member]
Subsequent Event [Line Items]
Operating lease expiration date	Dec. 31, 2015
Subsequent Event
Subsequent Event [Line Items]
Interest only period start date				Mar. 01, 2015
Interest only period end date				Feb. 01, 2016
Number of remaining principal payments				8
Expiration date				Oct. 01, 2016
Line of credit facility final payment	937,500			1,162,500
Line of credit facility final payment percentage	3.75%			4.65%
Prepayment penalty expiration date				Feb. 29, 2016
Percentage of penalty for prepaying loan before maturity				2.00%
Warrants Expiration Term				5 years
Number of warrants issued				61,467
Warrants exercise price for shares				$ 2.22
Subsequent Event | Controlled Equity Offering Facilities [Member]
Subsequent Event [Line Items]
Proceeds from issuance of common stock through controlled equity offering facilities, net					4,200,000
Subsequent Event | Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Price per common share including accompanying warrants					$ 2.75
Common stock, shares sold					1,579,124
Proceeds from issuance of common shares and warrants in offering, gross					4,300,000
Proceeds from issuance of common stock through controlled equity offering facilities, net					$ 4,200,000
Subsequent Event | Further Amended Operating Lease [Member]
Subsequent Event [Line Items]
Operating lease expiration date						Dec. 31, 2015

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Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended
	Mar. 04, 2014	Oct. 31, 2010	Dec. 31, 2014 Segment	Sep. 30, 2012	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Number of reportable segment			1
Fair value of investments denominated in Euros			$ 0		$ 2.6
Proceeds from issuance of common stock and warrants in offering gross	43.0	15.5
Common stock offering period			At the beginning of a 12-month offering period or at the end of one of the two related six-month purchase periods.
Employee Stock Purchase Plan [Member]
Significant Accounting Policies [Line Items]
Purchase price of a share as a percentage of fair market value			85.00%
Royalty Agreement [Member]
Significant Accounting Policies [Line Items]
Revenue participation right payments			25.0	25.0
Fair value of warrants issued in connection with participation agreement			$ 3.1	$ 3.1
Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of assets			3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of assets			5 years

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Stockholders' Equity - Additional Information 3 (Detail) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2014 PurchasePeriod
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share of common stock value		25,000
Number of shares issued under employee stock purchase plan		99,049,000
Shares Available for Future Grant		1,104,000
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of a share as a percentage of fair market value		85.00%
Duration of offering period		12 months
Number of purchase periods in each offering period		2
Duration of each purchase period		6 months
Number of shares authorized under employee stock purchase plan		500,000
Common stock available for issuance automatic increase period		10 years
Common stock available for issuance automatic increase maximum number of shares		1.00%
Additional number of shares of common stock reserved for issuance	271,720
Shares Available for Future Grant		431,672

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Subsequent Events

12 Months Ended

Dec. 31, 2014

Subsequent Events [Abstract]

Subsequent Events

14. Subsequent Events

On February 27, 2015, the Company entered into a third amendment (the “Amendment”), to the Loan Agreement with the Lenders. The Amendment modifies the loan repayment terms to be interest-only from March 1, 2015 to February 1, 2016, followed by eight equal monthly payments of principal and interest through the new maturity date of October 1, 2016. In addition, the final payment will be increased from $937,500 (3.75%) to $1,162,500 (4.65%) of the total loan facility, and will become due on the new maturity date, or such earlier date specified in the Loan Agreement. If the Company repays all or a portion of the loan prior to February 29, 2016 as part of a refinancing with another lender, a prepayment fee equal to 2% of the then outstanding principal balance will be due to the Lenders. As a result of the Amendment, the Lenders were issued five-year warrants to purchase an aggregate of up to 61,467 shares of the Company’s common stock at a per share exercise price of $2.22.

In January and February 2015, the Company sold an aggregate of 1,579,124 shares of common stock under the Sales Agreement, as amended, at an average price of approximately $2.75 per share for gross proceeds of $4.3 million and net proceeds of $4.2 million, after deducting Cantor’s commission. See Note 10 for further details.

In January 2015, the lease for the Company’s facility at 395 Oyster Point Boulevard in South San Francisco, California was amended to extend the expiration date to December 31, 2015. See Note 9 for further details.

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Other Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2014

Payables And Accruals [Abstract]

Summary of Other Accrued Liabilities

Other accrued liabilities as of December 31 were as follows (in thousands):

	2014		2013
Accrued outside services	$	2,656	$	1,249
Accrued professional services		355		263
Other accruals		76		133
Total other accrued liabilities	$	3,087	$	1,645

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Stockholders' Equity - Additional Information 1 (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended			2 Months Ended
	Mar. 04, 2014	Oct. 31, 2010	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2015	Dec. 31, 2011	Aug. 31, 2011	Feb. 27, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Preferred stock, shares authorized			10,000,000
Preferred stock, shares outstanding			0	0
Common stock, voting rights			One vote per share
Shares of common stock issued			66,102,000	54,344,000
Warrants, exercise prices per share			$ 2.52	$ 2.52
Proceeds from issuance of common stock and warrants in offering gross	$ 43,000,000	$ 15,500,000
Proceeds from issuance of common shares and warrants in offering, net	40,000,000
Proceeds from issuance of common stock through controlled equity offering facilities, net			14,292,000	11,986,000	17,620,000
Series A warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrant expiration description			The Series A warrants expired unexercised on December 4, 2014.
Series B warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrant expiration description			The Series B warrants will expire on or before the later of 30 days following any final date assigned by the Food and Drug Administration as the Prescription Drug User Fee Act action date for vosaroxin (the “PDUFA date”) and September 4, 2015, but in no event later than March 4, 2016
Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock issued			66,102,000	54,344,000	51,565,000		46,774,000
Underwritten Offering [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock issued	4,650,000
Price per common share including accompanying warrants	$ 9.25
Underwritten Offering [Member] | Series A warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants, exercise prices per share	$ 8.50
Underwritten Offering [Member] | Series B warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants, exercise prices per share	$ 12.00
Controlled Equity Offering Facilities [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, offering value								20,000,000
Common stock sales agreement, date			2011-08
Common stock sales agreement amended, date			2013-04
Issuance of common stock, remaining offering value			6,800,000
Controlled Equity Offering Facilities [Member] | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock through controlled equity offering facilities, net						4,200,000
Issuance of common stock, remaining offering value									2,500,000
Controlled Equity Offering Facilities [Member] | Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Price per common share including accompanying warrants			$ 2.88
Common stock, shares sold			5,113,876
Proceeds from issuance of common shares and warrants in offering, gross			14,700,000
Proceeds from issuance of common stock through controlled equity offering facilities, net			14,300,000
Controlled Equity Offering Facilities [Member] | Common Stock [Member] | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Price per common share including accompanying warrants						$ 2.75
Common stock, shares sold						1,579,124
Proceeds from issuance of common shares and warrants in offering, gross						4,300,000
Proceeds from issuance of common stock through controlled equity offering facilities, net						4,200,000
Additional Controlled Equity Offerings Facilities [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in aggregate controlled equity offering agreement as per amendment			$ 30,000,000
Issuance of common stock, commission percentage			3.00%

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Financial Instruments - Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities (Detail) (Warrant Liability [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Warrant Liability [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Beginning Balance	$ 7,931	$ 8,070
Change in fair value of warrant liability	(3,892)	(96)
Exercise of warrants	(496)	(43)
Ending Balance	$ 3,543	$ 7,931

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CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2011	$ 28,020	$ 5	$ 429,142	$ 19	$ (401,146)
Beginning Balance, shares at Dec. 31, 2011		46,774,000
Issuance of common stock through controlled equity offering facilities, net of issuance costs	17,620		17,620
Issuance of common stock through controlled equity offering facilities, net of issuance costs, shares		3,714,000
Issuance of common stock pursuant to warrant exercises	3,130		3,130
Issuance of common stock pursuant to warrant exercises, shares		801,000
Issuance of common stock pursuant to stock option exercises	330		330
Issuance of common stock pursuant to stock option exercises, shares		146,000
Issuance of common stock under employee stock purchase plans	172		172
Issuance of common stock under employee stock purchase plans, shares		84,000
Issuance of common stock to employees, shares		46,000
Issuance of warrants to purchase common stock	3,893		3,893
Stock-based compensation expenses—employees	2,402		2,402
Stock-based compensation expenses—non-employees	322		322
Net loss	(43,951)				(43,951)
Unrealized gain (loss) on available-for-sale securities	19			19
Ending Balance at Dec. 31, 2012	11,957	5	457,011	38	(445,097)
Ending Balance, shares at Dec. 31, 2012		51,565,000
Issuance of common stock through controlled equity offering facilities, net of issuance costs	11,986		11,986
Issuance of common stock through controlled equity offering facilities, net of issuance costs, shares		2,535,000
Issuance of common stock pursuant to warrant exercises	88		88
Issuance of common stock pursuant to warrant exercises, shares		18,000
Issuance of common stock pursuant to stock option exercises	230		230
Issuance of common stock pursuant to stock option exercises, shares		104,000
Issuance of common stock under employee stock purchase plans	309		309
Issuance of common stock under employee stock purchase plans, shares		97,000
Issuance of common stock to employees, shares		25,000
Stock-based compensation expenses—employees	3,581		3,581
Stock-based compensation expenses—non-employees	304		304
Net loss	(34,598)				(34,598)
Unrealized gain (loss) on available-for-sale securities	(41)			(41)
Ending Balance at Dec. 31, 2013	(6,184)	5	473,509	(3)	(479,695)
Ending Balance, shares at Dec. 31, 2013	54,344,000	54,344,000
Issuance of $43,013 of common stock and warrants in underwritten offering, net of issuance costs of $2990	40,024	1	40,023
Issuance of common stock and warrants in underwritten offering, net of issuance costs, shares		4,650,000
Issuance of common stock through controlled equity offering facilities, net of issuance costs	14,292	1	14,291
Issuance of common stock through controlled equity offering facilities, net of issuance costs, shares		5,114,000
Issuance of common stock pursuant to warrant exercises	949		949
Issuance of common stock pursuant to warrant exercises, shares		1,323,000
Issuance of common stock pursuant to stock option exercises	1,226		1,226
Issuance of common stock pursuant to stock option exercises, shares	565,000	566,000
Issuance of common stock under employee stock purchase plans	282		282
Issuance of common stock under employee stock purchase plans, shares	99,049,000	99,000
Issuance of common stock to employees, shares		6,000
Stock-based compensation expenses—employees	5,882		5,882
Stock-based compensation expenses—non-employees	337		337
Net loss	(43,002)				(43,002)
Unrealized gain (loss) on available-for-sale securities	(4)			(4)
Ending Balance at Dec. 31, 2014	$ 13,802	$ 7	$ 536,499	$ (7)	$ (522,697)
Ending Balance, shares at Dec. 31, 2014	66,102,000	66,102,000

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Loss per Common Share

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Loss per Common Share

3. Loss per Common Share

Basic loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per common share is computed by dividing (a) net loss, less any anti-dilutive amounts recorded during the period for the change in the fair value of warrant liabilities, by (b) the weighted-average number of common shares outstanding for the period plus dilutive potential common shares as determined using the treasury stock method for options and warrants to purchase common stock.

The following table sets forth the computation of basic and diluted loss per common share for the periods presented (in thousands, except per share amounts):

	Year Ended December 31,
	2014			2013			2012
Numerator:
Net loss—basic	$	(43,002	)	$	(34,598	)	$	(43,951	)
Adjustment for change in fair value of warrant liability		(3,892	)		—			—
Net loss—diluted	$	(46,894	)	$	(34,598	)	$	(43,951	)
Denominator:
Weighted-average common shares outstanding—basic		60,057			52,249			48,146
Dilutive effect of warrants		1,453			—			—
Weighted-average common shares outstanding—diluted		61,510			52,249			48,146
Net loss per common share:
Basic	$	(0.72	)	$	(0.66	)	$	(0.91	)
Diluted	$	(0.76	)	$	(0.66	)	$	(0.91	)

The following table represents the potential common shares issuable pursuant to outstanding securities as of the related period end dates that were excluded from the computation of diluted loss per common share because their inclusion would have had an anti-dilutive effect (in thousands):

	As of December 31,
	2014		2013		2012
Warrants to purchase shares of common stock		8,978		9,978		10,359
Options to purchase shares of common stock		10,584		7,611		6,288
Outstanding securities not included in calculations		19,562		17,589		16,647

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Income Taxes - Loss before Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. operations	$ (32,696)	$ (29,963)	$ (43,951)
Foreign operations	(10,306)	(4,635)
Loss before provision for income taxes	$ (43,002)	$ (34,598)	$ (43,951)

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Notes Payable (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Summary of Future Minimum Payments Under Loan Agreement

Aggregate future minimum payments due under the Loan Facility as of December 31, 2014 were as follows (in thousands):

Year ending December 31,	Total
2015	$	8,814
Total minimum payments		8,814
Less amount representing interest		(352	)
Notes payable, gross		8,462
Unamortized discount on notes payable		(84	)
Accretion of final payment		879
Notes payable, balance		9,257
Less current portion of notes payable		(9,257	)
Non-current portion of notes payable	$	—

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Financial Instruments - Summary of Available-for-Sale Securities in Unrealized Loss Position (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross Unrealized Losses	$ 7
Estimated Fair Value	11,782
U.S. corporate debt obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gross Unrealized Losses	7
Estimated Fair Value	$ 11,782

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Guarantees and Indemnification

12 Months Ended

Dec. 31, 2014

Commitments And Contingencies Disclosure [Abstract]

Guarantees and Indemnification

13. Guarantees and Indemnification

As permitted under Delaware law and in accordance with the Company’s Bylaws, the Company indemnifies its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The indemnification agreements with the Company’s officers and directors terminate upon termination of their employment, but the termination does not affect claims for indemnification relating to events occurring prior to the effective date of termination. The maximum amount of potential future indemnification is unlimited; however, the Company’s officer and director insurance policy reduces the Company’s exposure and may enable the Company to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification agreements is minimal. In addition, in the ordinary course of business the Company enters into agreements, such as licensing agreements, clinical trial agreements and certain services agreements, containing standard indemnifications provisions. The Company believes that the likelihood of an adverse judgment related to such indemnification provisions is remote. Accordingly, the Company has not recorded any liabilities for any of these agreements as of December 31, 2014.