ceru-10k_20151231.htm

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 such shorter 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 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 (Section 232.405 of this chapter) 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 if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) 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. o

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

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

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the registrant as of June 30, 2015 was approximately $92,191,525.60, based on the closing price of the registrant’s common stock on The NASDAQ Global Market.

As of March 1, 2016, there were 27,363,965 of the Registrant’s common shares, $0.0001 par value, issued and outstanding.

Any statements in this Annual Report on Form 10-K about our future expectations, plans and prospects, including statements about the clinical development of our product candidates, statements about our estimated research and development expenses and sufficiency of cash to fund specified use of cash and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “hypothesize,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “would,” and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: the uncertainties inherent in the initiation of clinical trials, availability and timing of data from ongoing and future clinical trials and the results of such trials, whether preliminary results from a clinical trial will be predictive of the final results of that trial or whether results of early clinical trials will be indicative of the results of later clinical trials, expectations for regulatory approvals, availability of funding sufficient for our foreseeable and unforeseeable operating expenses and capital expenditure requirements and other factors discussed in Item 1A of this Annual Report on Form 10-K under the heading “Risk Factors”. In addition, any forward-looking statements included in this Form 10-K represent our views only as of the date hereof and should not be relied upon as representing our views as of any subsequent date. We specifically disclaim any obligation to update any forward-looking statements.

We are a clinical-stage, oncology-focused company applying our proprietary Dynamic Tumor Targeting™ Platform to develop differentiated therapies. We were incorporated under the laws of the State of Delaware on November 28, 2005 under the name Tempo Pharmaceuticals, Inc. In October 2008, we changed our name to Cerulean Pharma Inc.

Our Dynamic Tumor Targeting Platform is designed to create nanoparticle-drug conjugates, or NDCs, with the aim of providing safer and more effective therapies for patients living with cancer. NDCs consist of anti-cancer therapeutics, or payloads, covalently linked to a proprietary polymer. An important goal for all drugs is to maximize the net clinical benefit by increasing the desired therapeutic effect while reducing adverse effects. This is especially difficult with drugs used to treat cancer, where the goal is to destroy or inhibit growth of cancer cells without damaging healthy cells. We believe our NDCs concentrate their anti-cancer payloads inside tumor cells while sparing normal tissue because they are small enough to pass through the leaky pores of new blood vessels in tumors as an entry portal into tumor tissue, but are too large to pass through the pores of healthy blood vessels. Once inside tumors, we believe our NDCs are actively taken up into tumor cells where they slowly release their anti-cancer payloads, providing a durable inhibition of their targets.

We believe that the ability to combine our NDCs with other agents, either approved or experimental, is a key differentiating feature of our platform. Based on their properties and design, our NDCs have the potential to enable synergistic combination therapies that can offer better tolerability and efficacy. We believe that better tolerability can be achieved through the preferential accumulation of the NDC in the tumor cells while better efficacy can be achieved by combining drugs that have different and complementary mechanisms of action. Cancer is a multi-faceted disease that is rarely adequately addressed by one therapy. Tumor cells are genetically diverse and can rapidly resist and ultimately overcome a single-agent therapy by modulating various adaptive pathways; however, if multiple drugs simultaneously shut down multiple adaptive pathways, there is a greater chance of achieving favorable disease responses for an extended period of time.

Our platform has generated two-clinical stage NDCs. Our first platform-generated clinical candidate, CRLX101, is in Phase 2 clinical development in patients with renal cell carcinoma, or RCC, and in Phase 2 and Phase 1b clinical development in patients with ovarian cancer in combination with Avastin^®(bevacizumab) and paclitaxel, respectively. We refer to the ongoing Phase 2 randomized, controlled, company-sponsored trial comparing CRLX101 administered in combination with Avastin to investigator’s standard of care in patients who have received two or three prior lines of therapy as the RCC Trial. CRLX101 has been dosed in more than 350 patients and has shown activity in multiple tumor types, both as monotherapy and in combination with other cancer treatments. The United States Food and Drug Administration, or FDA, has granted CRLX101 fast track designation in combination with Avastin in metastatic RCC and orphan drug designation for the treatment of ovarian cancer. Our second platform-generated clinical candidate, CRLX301, is currently in Phase 1/2a clinical development. We intend to generate additional candidates, alone and potentially in collaboration with partners.

Our lead clinical candidate, CRLX101, is an NDC with a camptothecin payload. Camptothecin is a potent topoisomerase 1, or topo 1, inhibitor that was too toxic to develop in the clinic; however, CRLX101 reduces the toxicities associated with this highly potent agent, while increasing the payload concentration in tumors. In CRLX101, camptothecin is covalently linked to a nanoparticle backbone, which is a cyclodextrin-polyethylene glycol polymer. CRLX101 is designed to concentrate in tumors and slowly release the camptothecin inside tumor cells. CRLX101 inhibits topo 1 which is involved in cellular replication, and also inhibits hypoxia-inducible factor-1α, or HIF-1α, which research suggests is a master regulator of cancer cell survival mechanisms, and hypoxia-inducible factor-2α, or HIF-2α, which we believe may also be an important therapeutic target in RCC. Collectively, we will refer to HIF-1α and HIF-2α as HIF.

CRLX101 exemplifies the potential combinability features of NDCs. We are currently exploring four distinct approaches to combination therapy. We believe that we can safely deliver therapeutic levels of CRLX101 that durably inhibit topo 1 and HIF. We can combine this potential inhibition of topo 1 and HIF with additive mechanisms of cell killing using other drugs to potentiate the therapeutic effect. Opportunities for combination therapies that leverage CRLX101’s apparently favorable tolerability profile include, but are not limited to, the following four combination initiatives:

Our second clinical candidate, CRLX301, is an NDC with a docetaxel payload. Docetaxel is a commercially successful oncology drug that suffers from significant toxicities. We believe that CRLX301 will be differentiated from docetaxel because it is designed to concentrate more docetaxel in tumor cells and spare healthy tissue. In preclinical studies, CRLX301 delivered up to 10 times more docetaxel into tumors, compared to an equivalent milligram dose of commercially available docetaxel and was similar to or better than docetaxel in seven of seven animal models, with a statistically significant survival benefit seen in five of those seven models. In addition, preclinical data show that CRLX301 had lower toxicity than has been reported with docetaxel in similar preclinical studies.

The lead indications for CRLX101 are relapsed RCC and relapsed ovarian cancer. In relapsed RCC, CRLX101 is being studied in a randomized company-sponsored trial in combination with Avastin. In relapsed ovarian cancer, CRLX101 is being studied in (1) a single-arm Investigator-Sponsored Trial, or IST, sponsored by Massachusetts General Hospital as monotherapy and in combination with Avastin and (2) a company-sponsored trial in combination with paclitaxel. In addition, CRLX101 is being studied in (1) locally advanced rectal cancer in a Phase 1b/2 open-label IST sponsored by the University of North Carolina in combination with chemoradiotherapy and (2) solid tumors in a company-sponsored trial using a dose-intensive schedule of CRLX101 in patients with advanced solid tumors as a monotherapy as well as a combination therapy. We expect that CRLX101 will be studied in solid tumors in a National Cancer Institute-sponsored trial in combination with Lynparza beginning in the first half of 2016. Finally, CRLX301 is currently being explored in a company-sponsored trial in patients with advanced solid tumors.

Our Dynamic Tumor Targeting Platform is designed to create NDCs with the aim of providing safer and more effective therapies for patients living with cancer. While there have been significant advancements in the search for safe and effective cancer treatments, cancer still remains a difficult disease to treat. A major challenge in developing anti-cancer drugs is to engineer drugs that work at the sites of disease without adversely affecting healthy tissue. Our NDC platform is designed to create NDCs that accumulate high concentrations of active drug in tumor cells, without unwanted exposure to healthy tissue. We believe that increasing the concentration of active drug only in the tumor cells: 1) increases the likelihood of killing cancer cells; 2) reduces toxicity; and 3) enables the administration of our NDCs with other cancer drugs. The rationale for combination therapy is to use drugs that work by different mechanisms and that may have complementary effects, thereby decreasing the likelihood that resistant cancer cells will develop. When drugs with different effects are safely combined, the goal is to use each drug at an optimal dose, without intolerable side effects.

We believe our NDCs represent a new paradigm of drug therapy. NDCs are nanoparticles conjugated to anti-cancer payloads that are designed to accumulate in high levels in tumor cells while limiting exposure to healthy tissue.

Based on our preclinical studies and multiple clinical trials with CRLX101, we believe dynamic tumor targeting involves a three-step process, as described and illustrated below, each of which contributes to the achievement of desirable anti-cancer payload exposure in tumors and the reduction of undesirable anti-cancer payload exposure in normal tissue.

As clinical evidence of selective entry of CRLX101 in tumor tissue, we obtained differential post-therapy biopsies of tumor tissue and adjacent normal tissue from nine gastric patients. In nine of nine patient biopsies, taken between 24 and 48 hours after a single dose of CRLX101 was administered, the presence of camptothecin associated with CRLX101 was observed in the tumor tissue. In contrast, no definitive evidence of either the nanoparticle or camptothecin contained within the nanoparticle was observed in neighboring normal tissue. An illustrative example from one patient is shown in the figure below (in which camptothecin is referred to as “CPT” in the image on the right). These human data support our belief that our platform achieves higher drug concentrations in tumors compared to normal tissue. Further, the data showed inhibition of topo 1 and HIF-1α in post-treatment biopsies. In addition, we believe that the observed safety profile of our lead drug candidate, CRLX101, across more than 350 cancer patients, can be explained by the targeted delivery of the anti-cancer payload and the sparing of key organ systems from extensive drug exposure.

Clark et al. (2015). CRLX101, an investigational nanoparticle-drug conjugate, localizes in human tumors and not in adjacent healthy tissue after intravenous dosing. Mol Cancer Ther 14(12 Suppl 2):Abstract nr B33.

Our platform is applicable to a range of payloads. We have created NDCs with a variety of small molecule payloads, including, but not limited, to camptothecin, docetaxel, Jevtana^®(cabazitaxel), gemcitabine, methotrexate, and Xeljanz^® (tofacitinib). We select the small molecule payload based upon several factors, including our ability to conjugate the payload to our polymer, the biological rationale for prolonging circulation and providing sustained release of the payload, a relatively high potency of the payload, as well as intellectual property, regulatory and commercial considerations. As discussed below, in preclinical testing, our NDCs generally show improved pharmacokinetics, activity and tolerability as compared to the payload alone. We intend to develop NDCs alone and potentially in collaboration with partners.

Our platform has thus far generated a lead candidate, CRLX101, and a second candidate, CRLX301, and we believe it has the potential to further expand our pipeline, alone and in combination with partners.

In November 2015, we entered into a collaboration with AstraZeneca AB, or AstraZeneca, and the National Cancer Institute, or the NCI, to study the clinical combination of AstraZeneca’s drug Lynparza with CRLX101. We believe our NDCs enable therapeutic combinations because they are designed to concentrate anti-cancer payloads inside tumor cells and spare healthy tissue. Preclinical data generated by AstraZeneca with the Lynparza-CRLX101 combination demonstrated a synergistic anti-tumor effect from targeting two validated pathways. While PARP-topo 1 combinations have traditionally been limited by toxicity, preclinical work done by AstraZeneca suggests that a Lynparza-CRLX101 combination therapy could be clinically relevant.

The ability to combine our NDCs with other agents, either approved or experimental, is a key differentiating feature of our Dynamic Tumor Targeting Platform. Based on their properties and design, our NDCs have the potential to enable synergistic combination therapies that can offer both better tolerability and efficacy.

Drugs in a combination therapy are expected to demonstrate efficacy, which is often based on the drugs using multiple different mechanisms of action. Tumor cells are genetically diverse and can rapidly resist and ultimately overcome a single-agent therapy by modulating various adaptive pathways; however, if multiple drugs simultaneously shut down multiple adaptive pathways, there is a greater chance of achieving disease responses for an extended period of time. We believe our NDCs can be engineered to optimize the synergistic effects of combination therapy. We believe CRLX101 has opportunities in combination with each of the following four categories of cancer treatment: VEGF inhibitors such as Avastin, chemotherapy such as paclitaxel, DNA damage repair agents such as PARP inhibitors, and, potentially, immuno-oncology agents such as IDO inhibitors.

A drug eligible for combination therapy also should demonstrate a safety profile that does not overlap with or exacerbate the safety profile of the combination agent. The highlighted graph below represents the adverse events experienced by patients in the CRLX101 arm in an open-label, randomized Phase 2 clinical trial of CRLX101 as monotherapy in patients with advanced non-small cell lung cancer, or NSCLC, who had progressed through one or two prior chemotherapy regimens. This trial, which commenced in 2011, enrolled 157 patients, 97 of whom were administered CRLX101 as monotherapy. The other graphs below show the adverse events experienced by patients in clinical trials of approved camptothecin-class therapeutics, irinotecan and topotecan. CRLX101 was generally well tolerated in the NSCLC trial and the adverse event profile observed in the NSCLC trial supports our view that CRLX101 may be combinable with other anti-cancer therapies.

** IV topotecan label categorizes non-hematological AEs as (a) grade 1-2 and (b) grade 3-4, but categorizes hematological AEs as (a) grade 1-3 and (b) grade 4, so hematological AEs are shown with diagonal stripes.

Data not from comparative trial. Sources: Irinotecan (FDA label); Topotecan (FDA label), CRLX101 at 15mg/m² MTD (Phase 2 NSCLC Trial. 100 patients).

CRLX101 is currently in clinical trials in combination with an anti-angiogenic drug, Avastin, in relapsed RCC and relapsed ovarian cancer. We have demonstrated that CRLX101 is synergistic with Avastin in an ovarian xenograft model. We believe that this synergy is at least partly caused by the ability of CRLX101 to inhibit the up-regulation of HIF-1a caused by anti-angiogenic therapy. We have further confirmed this synergy in a highly metastatic ovarian cancer orthotopic tumor model, as well as in a triple-negative breast cancer orthotopic tumor model. We have observed the synergy of CRLX101 with other VEGF inhibitors such as Votrient^® (pazopanib) and Zaltrap^® (ziv-aflibercept).

We have conducted animal tumor model studies comparing CRLX101 to certain leading anti-angiogenesis drugs and the combination of CRLX101 and these anti-angiogenesis drugs. In these studies, we treated nude mouse xenograft models in which human A2780 ovarian cancer tumor cells were implanted subcutaneously in mice and allowed to establish tumors. We administered 5 mg/kg CRLX101 weekly by intravenous infusion alone or in combination with one of three different antiangiogenic drugs: Avastin, Zaltrap or Votrient. Avastin was dosed intravenously at 5 mg/kg twice per week. Zaltrap was dosed intraperitoneally at 25 mg/kg twice per week. Votrient was dosed orally at 150 mg/kg daily. Vehicle-treated mice were dosed with saline. Each dose group consisted of ten animals. We administered a CRLX101 dose level that was half the maximum-tolerated dose so that we could compare the effect of the applicable CRLX101 combination to CRLX101 as monotherapy. All other dose levels were the maximum effective dose in this model, as indicated by the literature. For the analysis of HIF-1a in tumors, mice were dosed for ten days, and three days following the final dose tumors were flash-frozen and HIF-1a protein levels were measured via western blot analysis, quantified using infrared fluorescence detection, normalized to actin levels and compared to HIF-1a protein levels from saline-treated mice. For the survival analysis, mice were dosed for three weeks, tumors were measured using calipers twice per week, and each animal was euthanized at the earlier of the time when its tumor reached a volume of 2,000 cubic millimeters or the end of the study.

These HIF-1a protein expression and survival rate results are illustrated in the graphs below.

Pham et al. (2015). Translational impact of nanoparticle-drug conjugate CRLX101 with or without bevacizumab in advanced ovarian cancer. Clin Cancer Res 21(4):808-18.

Our goal is to be a leader in the discovery, development and commercialization of NDCs for the treatment of patients with inadequately treated forms of cancer. Key elements of our strategy to achieve this goal are to:

Our current development stage pipeline consists of CRLX101 and CRLX301. As described in more detail below, we are pursuing clinical development of CRLX101 in two lead indications, and we began clinical development of CRLX301 in 2014.

Our lead clinical candidate, CRLX101, is a dynamically tumor targeted NDC in Phase 2 clinical development and has the potential to improve outcomes for patients in combination with other cancer treatments. CRLX101 has shown activity as monotherapy and in combination with other cancer treatments, in multiple tumor types. CRLX101 is in Phase 2 clinical development and has been administered to more than 350 patients. The FDA has granted CRLX101 fast track designation in combination with Avastin in metastatic RCC and orphan drug designation for the treatment of ovarian cancer.

We believe CRLX101, which contains camptothecin as its anti-cancer payload, is a potent, durable and combinable inhibitor of topo 1, a commercially validated cancer target, and HIF, a novel target of increasing interest in cancer research. Two products that have been marketed by other companies, irinotecan and topotecan, inhibit topo 1, but their clinical use is associated with severe toxicities. Recent research suggests that HIF, and in particular the HIF subunit HIF-la, is a master regulator of multiple cancer cell survival pathways.

We have demonstrated in preclinical studies that CRLX101 is a potent, durable and combinable inhibitor of topo 1 and HIF. We believe that the properties of CRLX101 could translate into important benefits for patients. We are focusing the clinical development of CRLX101 on cancer indications in which we expect the durable inhibition of topo 1 and HIF, in combination with other cancer treatments, will lead to differentiated efficacy. We are exploring combinations with VEGF inhibitors such as Avastin, chemotherapy such as paclitaxel, DNA damage repair agents such as PARP inhibitors, and, potentially, combinations with immuno-oncology agents such as IDO inhibitors.

We are pursuing development of CRLX101 in combination with anti-cancer therapies in multiple ongoing clinical development programs that include company-sponsored trials and ISTs. Our two lead indications are RCC, or kidney cancer, and ovarian cancer:

Data from this clinical trial was presented at the 2015 annual meetings of the American Society of Clinical Oncology and the Kidney Cancer Association Annual Meeting. The median PFS of patients in the trial was 9.9 months. Based on third-party published data, the expected PFS of the standard of care in this setting is approximately 3.6 months. In addition, the RECIST partial response rate of patients in the trial was 23%. Several recent studies in advanced RCC suggest that after treatment with a TKI, subsequent therapies, including Avastin alone, achieve RECIST partial response rates of between 2% and 4%.

We are conducting a Phase 1b single-arm company-sponsored trial of CRLX101 in combination with weekly paclitaxel in patients with relapsed ovarian cancer in collaboration with the GOG Foundation, Inc. (formerly known as the Gynecologic Oncology Group), or GOG. This Phase 1b multi-center, open-label, dose-escalation study combines CRLX101 with weekly paclitaxel in up to 24 patients with recurrent or persistent epithelial ovarian, fallopian tube or primary peritoneal cancer. The trial is designed to identify the maximum tolerated dose as well as pharmacokinetics, safety and tolerability of CRLX101 in combination with weekly paclitaxel. We will also evaluate preliminary evidence of efficacy.

CRLX301, our second platform-generated NDC clinical candidate, is an NDC with docetaxel as its anti-cancer payload. CRLX301 is designed to concentrate in tumors and slowly release docetaxel inside tumor cells. In preclinical studies, CRLX301 delivered up to 10 times more docetaxel into tumors, compared to an equivalent milligram dose of commercially available docetaxel and was similar to or better than docetaxel in seven of seven animal models, with a statistically significant survival benefit seen in five of those seven models. In addition, preclinical data show that CRLX301 had lower toxicity than has been reported with docetaxel in similar preclinical studies. CRLX301 is currently in Phase 1/2a clinical development.

Docetaxel, a member of the taxane family, is a highly active chemotherapeutic that binds to microtubules to trigger cell death in dividing cells. Docetaxel is extensively used in clinical practice and is FDA-approved for the treatment of locally advanced or metastatic NSCLC, locally advanced squamous cell carcinoma of the head and neck, androgen-independent prostate cancer, locally advanced or metastatic breast cancer and advanced gastric cancer. Moreover, other tumor types are known to be sensitive to docetaxel. Docetaxel causes toxicities, including death attributable to toxicities, hepatotoxicity, neutropenia, hypersensitivity, severe fluid retention and peripheral neuropathy. These toxicities can lead to dose adjustments, treatment discontinuation and extensive supportive care.

Because CRLX301 is synthesized in a similar manner as CRLX101, we can utilize some common intermediates and manufacturing facilities, thereby creating manufacturing synergies across the two programs. We believe the clinical development risk of CRLX301 is somewhat mitigated because the efficacy of docetaxel in humans is extensively validated. In addition, the safety risk of the NDC platform is reduced since CRLX101, sharing the identical nanoparticle backbone, has been tested in over 350 patients without serious toxicities attributed to the component parts of the NDC.

Our target product profile for CRLX301 aims to demonstrate improved efficacy, safety and combinability over docetaxel. The potential advantages of CRLX301 would be to increase docetaxel’s proven anti-tumor activity by targeting sustained release of docetaxel from within tumor cells, thereby achieving sustained drug concentrations in tumor cells. We expect lower tissue distribution with CRLX301 compared to docetaxel, based on preclinical studies, potentially enhancing tolerability.

We believe that the potentially enhanced therapeutic benefit and favorable safety profile for CRLX301 would enable combination therapies incorporating CRLX301 with other anti-cancer therapies that may not be combinable today due to docetaxel’s toxicities.

A key component to our strategy is to collaborate with other companies to discover and develop new NDCs. In November 2015, we entered into a collaboration with AstraZeneca and the NCI, part of the National Institutes of Health, to study AstraZeneca’s drug Lynparza in combination with CRLX101. Lynparza is an FDA-approved PARP inhibitor for the treatment of certain advanced ovarian cancers. The collaboration will explore the combination of PARP and topo 1 inhibition. Preclinical data generated by AstraZeneca with the Lynparza-CRLX101 combination demonstrated a synergistic anti-tumor effect from targeting two validated pathways. While PARP-topo 1 combinations have traditionally been limited by toxicity, we believe that with our NDC and the work AstraZeneca has done to define a clinical dose and schedule we may be able to develop an effective and tolerable Lynparza-CRLX101 combination. The NCI will conduct a combination Phase 1/2a trial.

We are collaborating with Massachusetts General Hospital and the GOG on two clinical trials in relapsed ovarian cancer. The first trial is a Phase 2 single-arm IST of CRLX101 as monotherapy and in combination with Avastin in patients with relapsed ovarian cancer. This IST is being conducted at Massachusetts General Hospital and affiliated Harvard University teaching hospitals. The second trial is a company-sponsored Phase 1b open label trial that we are conducting in collaboration with the GOG testing CRLX101 in combination with weekly paclitaxel in patients with relapsed ovarian cancer.

The biopharmaceutical industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technology, knowledge, experience and scientific resources provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions and governmental agencies and public and private research institutions. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

Many of our competitors have significantly greater financial, manufacturing, marketing, drug development, technical and human resources than we do. These competitors also compete with us in recruiting and retaining top qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

Due to the large unmet medical need, global demographics and relatively attractive reimbursement dynamics, the oncology market is fiercely competitive. In each indication we are pursuing, there are approved cancer therapeutics and agents under clinical development for use as monotherapy and combination therapy. Each of the top ten global pharmaceutical companies and most of the mid-size pharmaceutical companies has a strong research and development and commercial presence in oncology. Smaller companies also focus on oncology, including, without limitation, companies such as Acceleron Pharma, Inc., Agios Pharmaceuticals, Inc., AVEO Pharmaceuticals Inc., ARIAD Pharmaceuticals, Inc., Argos Therapeutics, Inc., BIND Therapeutics, Inc., Clovis Oncology, Inc., Endocyte, Inc., Epizyme, Inc., Exelixis, Inc., ImmunoGen, Inc., Incyte Corporation, Infinity Pharmaceuticals, Inc., MacroGenics, Inc., Medivation, Inc., Merrimack Pharmaceuticals, Inc., OncoMed Pharmaceuticals, Inc., Onconova Therapeutics, Inc., Pharmacyclics, Inc. (which was acquired by AbbVie Inc. on May 26, 2015), Puma Biotechnology, Inc., Seattle Genetics, Inc., TESARO, Inc. and Verastem, Inc.

Companies with marketed nanotechnology-based oncology products include Celgene Corporation (Abraxane® (nab-paclitaxel) indicated for breast cancer, NSCLC and pancreatic cancer), Janssen Products, LP (Doxil indicated for ovarian cancer and, in combination with Velcade^® (bortezomib), for multiple myeloma), Merrimack Pharmaceuticals, Inc. (Onivyde^TM (irinotecan liposome injection) indicated for pancreatic and colorectal cancer) and Spectrum Pharmaceuticals, Inc. (Marqibo® (vincristine sulfate liposome injection) indicated for relapsed Philadelphia chromosome-negative acute lymphoblastic leukemia). Companies with nanotechnology-based oncology product candidates in clinical development include, without limitation, BIND Therapeutics, Inc. (BIND 014 for squamous NSCLC, urothelial carcinoma, cholangiocarcinoma, cervical cancer and squamous cell carcinoma of the head and neck), Celator Pharmaceuticals, Inc. (CPX-351 for acute myeloid leukemia), Celsion Corporation (ThermoDox (lyso-thermosensitive liposomal doxorubicin) for liver cancer and breast cancer), Cytimmune Sciences, Inc. (CYT-6091 for NSCLC), Cristal Delivery B.V. d/b/a Cristal Therapeutics (CriPec® docetaxel for oncology), Nektar Therapeutics (NKTR102 for solid tumors), Nippon Kayku Seizo Co., Ltd. (NK105 in breast cancer), Starpharma Holdings Ltd. (DEP® docetaxel for oncology), and Supratek Pharma Inc. (SP1049C for solid tumors).

We believe CRLX101 is the only non-nucleotide oncology product candidate in clinical development that inhibits the HIF pathway as well as topo 1. F. Hoffmann-La Roche Ltd. acquired a Locked Nucleic Acid oncology product candidate that targets HIF-1α (SPC-2968, which was referred to as EZN-2968 when it was being developed by Enzon Pharmaceuticals, Inc. and Santaris Pharma A/S). Peloton Therapeutics, Inc. has developed an orally bioavailable small molecule inhibitor specific to HIF-2α that is in a Phase 1 clinical development in clear cell RCC (PT2385). In addition, there are drugs and biologics in development that could compete with CRLX101 in each of its lead indications.

In relapsed RCC, the FDA-approved therapies commonly used for treatment represent several mechanistic classes— immune checkpoint inhibitors of PD-1, TKIs, including small molecules as well as the antibody to VEGF ligand, Avastin, and inhibitors of mTOR—and there are no approved cytotoxic drugs that we are aware of. Bristol-Myers Squibb Company’s PD-1 antibody Opdivo is approved in relapsed RCC following progression on one targeted therapy. There are also several drugs in development that have the potential to obtain FDA marketing approval and change the standard of care. Antibodies against PD-1/PD-L1 and CTL-A4 are in late stage development in first line RCC, both as monotherapies and in combination with other agents including Avastin and small molecule TKIs. For example, Bristol-Myers Squibb is developing Opdivo in combination with Yervoy™ (ipilimumab) in first line, Merck is developing Keytruda® (pembrolizumab) in combination with Votrient in first line and Roche is developing a PD-L1 inhibitor, atezolizumab, in combination with Avastin in first line. Argos Therapeutics, Inc. is developing AGS-003, a dendritic cell therapy, in first line RCC for patients with unfavorable risk. New small molecule TKIs are also in development. Exelixis Inc.’s TKI, Cometriq^® (cabozantinib), TRACON Pharmaceuticals, Inc.’s TRC105, and Acceleron Pharma, Inc.’s dalantercept (the latter two are in combination with Inlyta^® (axitinib)) are in development in second line or later stage relapsed RCC. Eisai Co., Ltd. is developing Lenvima® (lenvantinib) in combination with Afinitor® (everolimus) in second line. AVEO Pharmaceuticals, Inc. is developing tivozanib in third line. Regardless of the results of these trials, we believe that there will remain a place for VEGF targeted therapies, and therefore a role for CRLX101, if approved, in treating patients who progress on a VEGF targeted agent.

In relapsed ovarian cancer, there are multiple approved therapies, including most recently Avastin, in combination with chemotherapy, and Lynparza. Multiple companies are developing other therapeutic candidates, which are at various stages of development. For example, Abbvie Inc., Clovis Oncology, Inc., Medivation Inc., and TESARO Inc. all have PARP inhibitors in development in BRCA mutated ovarian cancer and breast cancer. ImmunoGen is also developing IMGN853 in folate receptor positive ovarian cancer. OncoMed Pharmaceuticals is developing demcizumab, and Genentech, Inc. is developing DMOT4039A. Although each of these agents has the potential to be used in combination with CRLX101, thereby expanding the market for CRLX101, they also have the potential to compete with CRLX101.

Several companies are developing taxane-containing nanoparticles for oncology that are competitors to CRLX301. For example, BIND Therapeutics Inc.’s BIND-014 is a docetaxel containing nanoparticle in active clinical development in squamous NSCLC as well as cervical cancer and head and neck cancer. Nippon Kayaku’s NK105 is a paclitaxel micelle nanoparticle in late stage clinical development for breast and stomach cancer. Drug-polymer conjugated nanoparticles, such as CTI BioPharma’s paclitaxel poliglumex, are in late stage clinical development as maintenance therapy for advanced ovarian cancer.

The key competitive factors affecting the success of all our therapeutic product candidates, if approved, are likely to be their efficacy, safety, dosing convenience, price, the level of generic competition and the availability of reimbursement from government and other third party payors.

We strive to protect the proprietary technologies that we believe are important to our business, including seeking and maintaining patent protection intended to protect, for example, the technology platforms used to generate our product candidate, related technologies and/or other aspects of the inventions that are important to our business. We also rely on trade secrets and careful

monitoring of our proprietary information to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection.

We plan to continue to expand our intellectual property estate by filing patent applications directed to improvements of our platform as well as dosage forms, methods of treatment and additional compositions created or identified from our platform and ongoing development of our product candidates. Our success will depend significantly on our ability to obtain and maintain patent and other proprietary protection for commercially important technology, inventions and know-how related to our business; defend and enforce our patents; maintain our licenses to use intellectual property owned by third parties; preserve the confidentiality of our trade secrets; and operate without infringing the valid and enforceable patents and other proprietary rights of third parties. We also rely on know-how, continuing technological innovation and in-licensing opportunities to develop, strengthen, and maintain our proprietary positions.

Our patent portfolio includes issued patents and pending applications worldwide. These patents and applications fall into three broad categories: (1) NDCs comprising covalent linkage of specific therapeutic agents to our proprietary cyclodextrin polyethylene polymer, or CDP, including without limitation CRLX101 and CRLX301; (2) methods of use of our NDCs; and (3) our evolving platform technology relating to polymeric NDCs.

We hold issued patents in the United States, Japan, and several other countries, covering the composition of matter of CRLX101 that expire in 2023 and 2024, excluding any potential patent term extension. Due to the ability of NDCs to target the “leaky” vasculature that is present in all solid tumors and CRLX101’s apparently favorable adverse event profile observed to date, we believe CRLX101 may have significant clinical utility in several cancer indications, particularly in combination with other cancer therapies. Our development focus is on tumor types where HIF is up-regulated, topo 1 inhibition is desirable, and drug combinations with CRLX101 can be pursued.

We hold issued patents in the United States, Japan, and several other countries covering the composition of matter of CRLX301 that expire in 2023 and 2024, excluding any potential patent term extension.

The base term of a United States patent is 20 years from the filing date of the earliest-filed non-provisional patent application from which the patent claims priority. The term of a United States patent can be lengthened by patent term adjustment, which compensates the owner of the patent for administrative delays at the United States Patent and Trademark Office, or USPTO. In some cases, the term of a United States patent is shortened by terminal disclaimer that reduces its term to that of an earlier-expiring patent.

The term of a United States patent may be eligible for patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Act, to account for at least some of the time the drug is under development and regulatory review after the patent is granted. With regard to a drug for which FDA approval is the first permitted marketing of the active ingredient, the Hatch-Waxman Act allows for extension of the term of one United States patent that includes at least one claim covering the composition of matter of an FDA-approved drug, an FDA-approved method of treatment using the drug, and/or a method of manufacturing the FDA-approved drug. The extended patent term cannot exceed the shorter of five years beyond the non-extended expiration of the patent or 14 years from the date of the FDA approval of the drug. Some foreign jurisdictions, including Europe and Japan, have analogous patent term extension provisions which allow for extension of the term of a patent that covers a drug approved by the applicable foreign regulatory agency. In the future, if and when our pharmaceutical products receive FDA approval, we expect to apply for patent term extensions on patents covering those products, their methods of use, and/or methods of manufacture.

In addition to patents, we rely on trade secrets and know-how to develop and maintain our competitive position. We typically rely on trade secrets to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. For example, significant elements of the making and formulating of our products are based on trade secrets and know-how that are not publicly disclosed. We protect trade secrets and know-how by establishing confidentiality agreements and invention assignment agreements with our employees, consultants, scientific advisors, contractors and commercial partners. These agreements provide that all confidential information developed or made known during the course of an individual or entity’s relationship with us must be kept confidential during and after the relationship. These agreements also provide that all inventions resulting from work performed for us or relating to our business and conceived or completed during the period of employment or assignment, as applicable, shall be our exclusive property. In addition, we take other appropriate precautions, such as physical and technological security measures, to guard against misappropriation of our proprietary technology by third parties.

We also seek trademark protection in the United States and in foreign jurisdictions where available and when appropriate. The name “CERULEAN” is a registered trademark in the United States, Australia, China, the European Union, India, Israel, Japan, South Korea, Liechtenstein, Mexico, Norway, Russia, Singapore, Switzerland, Turkey, and the Ukraine and is covered by a pending application for trademark registration in Canada. The trademark is solely owned by Cerulean Pharma Inc., in the field of pharmaceutical preparations as well as in the field of diagnostic and prognostic preparations. The Cerulean logo is a registered trademark in the United States and is solely owned by Cerulean Pharma Inc. CERULEAN and the Cerulean logo is a registered trademark in Mexico and is solely owned by Cerulean Pharma Inc. The term “Leadership in Nanopharmaceuticals” is a registered trademark in the United States and is solely owned by Cerulean Pharma Inc. The symbol ™ indicates a common law trademark. Other service marks, trademarks and trade names appearing elsewhere in this Annual Report on Form 10-K are the property of their respective owners.

In June 2009, we entered into two agreements with Calando Pharmaceuticals, Inc., or Calando, the CRLX101 Agreement and the Platform Agreement, each of which we subsequently amended. Under these agreements, Calando assigned and licensed to us certain assets. These assets include the clinical asset then known as IT-101, later renamed CRLX101, and rights to Calando’s cyclodextrin system for purposes of conjugating or complexing certain other therapeutic agents to the system.

Under the CRLX101 Agreement, we obtained certain rights to CRLX101. As noted below in the description of the Platform Agreement, Calando also assigned to us certain patents and patent applications, including, with respect to composition of matter and methods of use, for CRLX101. In addition, under the CRLX101 Agreement, Calando transferred ownership of the CRLX101 IND to Cerulean. Also, under the CRLX101 Agreement, Calando initially granted to us a worldwide, royalty bearing, exclusive (even as to Calando) license, with the right to grant sublicenses, to Calando’s interest under certain patents, patent applications, and know-how owned or controlled by Calando, to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CRLX101 formulated for intravenous, intrarterial, intrathecal and/or intraperitoneal therapy, to treat and/or prevent disease in humans. As noted below in the description of the Caltech Agreement, all of the patents, patent applications and know-how that were initially licensed to us by Calando under the CRLX101 Agreement and upon which CRLX101 is dependent are now directly licensed to us by Caltech, and we retained the license described above from Calando for patents, patent applications and know-how that are directed to other aspects of the cyclodextrin system but on which CRLX101 is not dependent. For purposes of our obligations to Calando under the CRLX101 Agreement, we treat the intellectual property licensed to us by Caltech as if it were still licensed to us by Calando. These licensed and assigned patent rights are described in more detail above under “Intellectual Property.”

Under the CRLX101 Agreement, we are obligated to use commercially reasonable efforts to develop CRLX101 throughout the world and, following the first commercial sale of CRLX101 in a particular country, to make CRLX101 commercially available in such country.

Upon entering the CRLX101 Agreement, we paid Calando approximately $1.3 million, which included the purchase of CRLX101 drug substance and drug product inventory. If we achieve certain development and sales events with CRLX101, we are obligated to pay milestone payments which could total, in the aggregate, $32.8 million. If we or one of our affiliates sells CRLX101, we are also required to pay tiered royalty payments ranging from low-to mid-single digits, depending on whether or not there is patent protection for CRLX101 at the time of sale as a percentage of worldwide net sales. Our royalty payment obligations in a particular country begin on the date of first commercial sale of CRLX101 in that country and end on the later of ten years from the date of first commercial sale of CRLX101 in that country or the expiration of all patents licensed to us by Caltech or Calando, referred to as Licensed Patent Rights, or assigned to us by Calando, referred to as the Assigned Patent Rights, which cover CRLX101 in that country. With respect to CRLX101 that is developed and sold by an unaffiliated third party to whom we grant a license or sublicense under any of the intellectual property that we purchased or licensed from Calando, we are required to pay Calando a percentage of the income we receive from the licensee or sublicensee to the extent attributable to such license or sublicense, subject to certain exceptions. The percentage of such sublicense income that we are obligated to pay Calando is in the low- to mid-double digits, and varies depending on the stage of development of CRLX101 at the time that we first provide or receive draft terms of a license arrangement with the third party that results in a license arrangement, unless the negotiations terminate, in which case the percentage depends on the development stage of CRLX101 when the negotiations restart.

We have the first right to enforce the Licensed Patent Rights and Assigned Patent Rights, other than one subset of licensed patents on which CRLX101 is not dependent, which Calando has the sole right to enforce.

We and Calando are required to indemnify each other for losses and expenses in connection with any third party claims arising out of the indemnifying party’s breach of the CRLX101 Agreement, the negligence or willful misconduct of the indemnifying party or its affiliates or sublicensees under the CRLX101 Agreement or any product liability arising out of CRLX101 developed, made, used or sold by or on behalf of the indemnifying party or its affiliates or sublicensees.

The CRLX101 Agreement will remain in effect until the expiration of all of our royalty obligations to Calando. We also have the right to terminate the CRLX101 Agreement for any reason on thirty days prior notice to Calando, in which case, unless we certify that the termination was due to specified safety concerns with CRLX101, we will grant Calando an exclusive (even as to Cerulean), royalty-free license, under the Assigned Patent Rights, to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CRLX101, we will assign the IND for CRLX101 to Calando and, if consistent with our business plans, we will discuss granting Calando a license under know-how that we developed that relates to CRLX101. If we fail to meet our diligence obligations under the CRLX101 Agreement after a specified cure period, the license may convert to a non-exclusive license and we will have to grant Calando a non-exclusive license under the Assigned Patent Rights to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CRLX101. If the license is converted to a non-exclusive license, the royalties payable to Calando will be reduced by a specified percentage. If we fail to meet our payment obligations under the agreement and are unable to cure such failure within specified time periods, Calando can terminate the agreement, we are obligated to grant Calando an exclusive (even as to Cerulean), royalty-free license, under the Assigned Patent Rights to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CRLX101 and to assign the IND for CRLX101 to Calando, resulting in our loss of rights to CRLX101. If we or one of our affiliates challenges the validity or enforceability of any of the licensed patents, Calando has the right to terminate the agreement. For any breach of the CRLX101 Agreement not described above, the non-breaching party’s sole remedy if such breach is not cured within a specified time period is to seek money damages from the breaching party.

Under the Platform Agreement, Calando assigned to us the Assigned Patent Rights and granted to us a worldwide, royalty bearing, exclusive (even as to Calando) license, with the right to grant sublicenses, to Calando’s interest under certain patents, patent applications, and know-how owned or controlled by Calando (a) to conduct research and development on the cyclodextrin system, including making improvements thereto, in order to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CDP-based Products and (b) to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CDP-based Products. The field of the license is the treatment and/or prevention of disease in humans. CDP-based Products are defined as products conjugated or complexed to the cyclodextrin system, other than any products containing cytolysin, tubulysin, certain second generation epothilones or a nucleic acid, which we refer to as Retained Products, and CRLX101, which is covered by the CRLX101 Agreement described above. Under the Platform Agreement, we are obligated to use commercially reasonable efforts to develop CDP-based Products throughout the world and, following the first commercial sale of CDP-based Product in a particular country, to make CDP-based Product commercially available in such country.

Upon entering the Platform Agreement, we paid to Calando approximately $1.2 million, which included the payment for assignment of the Assigned Patent Rights and cyclodextrin-containing polymers and precursor inventory. We granted Calando a worldwide, royalty-free, exclusive (even as to Cerulean), perpetual and irrevocable license, with the right to grant sublicenses, under the Assigned Patent Rights to research, develop, make, have made, use, market, offer to sell, sell and import the Retained Products.

If we achieve certain development and sales events with respect to any CDP-based Product, we are obligated to pay milestone payments which could total, in the aggregate, $18.0 million per CDP-based Product. Upon the initiation of our CRLX301 Phase 1 trial in December 2014, we made a milestone payment of $250,000 to Calando in January 2015. If we or one of our affiliates sells a CDP-based Product, we are also required to pay tiered royalty payments ranging from low-to mid-single digits, depending on whether or not there is patent protection at the time of sale, as a percentage of worldwide net sales. Our royalty payment obligations in a particular country begin on the first date of first commercial sale of the CDP-based Product in that country and end on the later of ten years from the date of first commercial sale of that CDP-based Product in that country or the expiration of all patents licensed or assigned from Calando which cover that CDP-based Product in that country. With respect to a CDP-based Product that is developed and sold by a third party to whom we grant a license or sublicense under any of the intellectual property that we licensed from Calando or that Calando assigned to us, we are required to pay Calando a percentage of the income we receive from the licensee or sublicensee to the extent attributable to such license or sublicense, subject to certain exceptions. The percentage of such sublicense income that we are obligated to pay Calando does not exceed the low-double digits.

We have the first right to enforce the licensed patent rights and the Assigned Patent Rights, other than one subset of licensed patents which Calando has the sole right to enforce.

We and Calando are required to indemnify each other for losses and expenses in connection with any third party claims arising out of the indemnifying party’s breach of the Platform Agreement, the negligence or willful misconduct of the indemnifying party or its affiliates or sublicensees under the Platform Agreement or any product liability arising out of a CDP-based Product developed, made, used or sold by or on behalf of the indemnifying party or its affiliates or sublicensees. Calando also indemnifies us for losses and expenses in connection with any third party claim arising out of a Retained Product developed, made, used or sold by or on behalf of Calando or its affiliates or licensees.

The Platform Agreement will remain in effect until the expiration of all of our royalty obligations to Calando. We also have the right to terminate the Platform Agreement for any reason on thirty days prior written notice to Calando, in which case we will grant Calando an exclusive (even as to Cerulean), royalty-free license, under Assigned Patent Rights, to research, develop, make, have made, use, market, offer to sell, distribute, sell and import the CDP-based Products and, if consistent with our business plans, we would discuss granting Calando a license under know-how that we developed that relates to the cyclodextrin system or CDP-based Products. If we fail to meet our diligence obligations under the agreement after a specified cure period, Calando may convert the license to a non-exclusive license and we will have to grant Calando a non-exclusive license under the Assigned Patent Rights to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CDP-based Products. If the license is converted to a non-exclusive license, the royalties payable to Calando will be reduced by a certain percentage. If we fail to meet our payment obligations under the agreement and are unable to cure such failure within specified time periods, Calando can terminate the agreement, resulting in our loss of rights to the CDP-based Products and an obligation to grant Calando an exclusive (even as to Cerulean), royalty-free license, under the Assigned Patent Rights to research, develop, make, have made, use, market, offer to sell, distribute, sell and import CDP-based Products. If we or one of our affiliates challenges the validity or enforceability of any of the licensed patents, Calando has the right to terminate the agreement. For any breach of the Platform Agreement not described above, the non-breaching party’s sole remedy if such breach is not cured within a specified time period is to seek money damages from the breaching party.

Certain of the patents, patent applications, and know-how licensed to us under the CRLX101 Agreement and the Platform Agreement were originally licensed to Calando by the California Institute of Technology, or Caltech, pursuant to an agreement entered into between Calando and Caltech in May 2000 and subsequently amended, which we refer to as the Calando/Caltech Agreement. In August 2013, we entered into an agreement with Calando and Caltech under which Calando terminated its rights and obligations under the Calando/Caltech Agreement and Caltech agreed to directly honor the exclusive license, including the right to grant further sublicenses, granted to us by Calando under the Caltech intellectual property formerly licensed to Calando.

We are obligated to pay Caltech minimum annual royalties and the costs it incurs to prosecute and maintain the licensed patent rights. We may offset those prosecution and maintenance costs against any milestones or royalties that we owe to Calando under the CRLX101 Agreement or the Platform Agreement.

Following the earlier of our receipt of notice from Calando that it has made certain payments to third parties or the first anniversary of the first commercial sale of a product covered by the Caltech patent rights, we will directly pay to Caltech the amounts that it would have been entitled to receive from Calando with respect to our sales of the licensed products, and we will pay to Calando the remainder of the royalties we owe them under the CRLX101 Agreement and the Platform Agreement.

We may terminate our rights and obligations to Caltech and Calando with respect to any of the Caltech licensed intellectual property either in its entirety or as to any jurisdiction or as to any part of the intellectual property upon a specified period of prior notice to Caltech and Calando. Caltech has the right to terminate the agreement if we fail to make a payment, or otherwise materially breach the agreement and fail to cure such breach within specified grace periods.

The Research Foundation of State University of New York on behalf of University at Buffalo

In August 2007, we entered into an exclusive license agreement with The Research Foundation of State University of New York on behalf of University at Buffalo, which we refer to as the SUNY Agreement. The SUNY Agreement has been amended four times, including to extend the time period for achieving certain diligence milestones, and the most recent amendment was entered into in September 2013. Under the SUNY Agreement, we have a worldwide, royalty bearing, exclusive license, with the right to grant sublicenses, for the treatment and/or prevention of disease in humans, under certain patent rights owned by SUNY, to research, develop, make, have made, use, offer for sale, sell, have sold, import and export certain products covered by the licensed patent rights.

We are required to diligently proceed with the research, development, manufacture, use and sale of licensed products under the agreement, to use commercially reasonable efforts to commercialize and market licensed products as soon as practicable, and to make licensed products available on commercially reasonable terms once introduced into the marketplace. In particular, we are required to fulfill specific development and regulatory milestones by particular dates and, during each calendar year prior to the first commercial sale of a licensed product, spend a specified amount on the research, development or commercialization of licensed products or precursor technologies or products, and if we fail to do so SUNY may elect to increase our license maintenance fee and, in the case of a second failure, our exclusive license will be converted to a non-exclusive license.

Under the SUNY Agreement, as of December 31, 2015, we had paid SUNY approximately $0.2 million in the aggregate, consisting of an upfront license fee, a field-of-use expansion fee, annual maintenance fees and reimbursement of patent-related fees incurred by SUNY. We are also obligated to pay SUNY an escalating annual license maintenance fee and development milestone payments which could total, in the aggregate, less than $0.1 million and royalties in the low single digits as a percentage of net sales by us, our affiliates or our sublicensees of licensed products.

SUNY retains the right to practice the licensed patent rights for educational purposes and internal research and development, including collaborations with researchers at other academic and non-profit research institutions. Any of the licensed patent rights claiming inventions that were funded by the government are subject to certain rights retained by the United States government under a law commonly called the Bayh-Dole Act. These rights include, among other things, a royalty-free, non-exclusive license for the United States government to practice these inventions. Any products used or sold in the United States and covered by these patents must be substantially manufactured in the United States, unless a waiver is obtained from the U.S. government.

SUNY controls prosecution and maintenance of the licensed patents, although we have an approval right over certain actions. We reimburse SUNY for all reasonable costs associated with filing, prosecuting and maintaining the licensed patent rights. SUNY has the first right to enforce the licensed patents against infringers in the licensed field. We have the right to enforce the licensed patents if SUNY does not institute an infringement action within a specified period of time.

We are required to indemnify SUNY for any claims and expenses resulting from the exercise or practice of the license granted to us, including liabilities arising from the production, manufacture, sale, use, lease or advertisement of the licensed products.

The SUNY Agreement will remain in effect until the expiration of all licensed patents and patent applications, unless we elect to earlier terminate the entire license, or the license with respect to certain patent families, subject to providing SUNY with a specified amount of prior written notice. SUNY has the right to terminate the SUNY Agreement if we have a bankruptcy action filed against us, have a receiver appointed for us, or if we materially breach the agreement and fail to cure such situation or breach within a specified grace period. The SUNY Agreement will automatically terminate if we cease to carry on our business, file for bankruptcy, become insolvent, make an assignment for the benefit of creditors, or challenge the validity or enforceability of any of the licensed patents.

We currently contract with third parties for the manufacture of our product candidates for preclinical studies and clinical trials and intend to do so in the future. We do not own or operate manufacturing facilities for the production of clinical or commercial quantities of our product candidates. We currently have no plans to build our own clinical or commercial scale manufacturing capabilities. To meet our projected needs for commercial manufacturing, third parties with whom we currently work will need to increase their scale of production or we will need to secure alternate suppliers. Although we rely on contract manufacturers, we have personnel with manufacturing experience to oversee our relationships with contract manufacturers.

Our contract manufacturers have manufactured what we believe to be sufficient quantities of CRLX101 drug product to support clinical trials through 2016, and have begun manufacturing additional supplies to continue clinical development of CRLX101 beyond 2016. The current drug substance and drug product manufacturing processes for CRLX101 are scaled to support Phase 2/3 clinical development under current Good Manufacturing Practice, or cGMP, standards. Although we believe our drug substance and drug product manufacturing processes are capable of supporting further development and scale up for commercial demand at a reasonable cost of goods, we are exploring more scalable and cost effective modifications to the drug substance manufacturing process. While we believe that our existing supplier of drug substance is capable of producing drug substance in commercial quantities, we are in the process of identifying a new third party drug product manufacturer capable of providing commercial quantities. If we are unable to arrange for third-party manufacturing with this or other alternative vendors, or fail to do so on commercially reasonable terms, we may not be able to successfully produce and market CRLX101.

Processes for producing CRLX301 have been developed and used successfully to produce drug substance and drug product for good laboratory practice, or GLP, safety studies and cGMP Phase 1/2a clinical supply. Improvements to both the drug substance manufacturing process and the drug product formulation are currently underway in preparation for Phase 2 development.

Both CRLX101 and CRLX301 include complicated polymer backbone structures as well as cytotoxic agents. Although these characteristics may limit alternative third party manufacturers, we believe that there are alternate sources of supply that can satisfy our clinical and commercial requirements, and we have or are pursuing back-up suppliers for certain stages of the manufacturing process. We cannot be certain, however, that identifying and establishing relationships with additional alternate sources, if necessary, would not result in significant delay or material additional costs.

We intend to build the commercial infrastructure in the United States necessary to effectively support the commercialization of CRLX101, if approved, and future oncology products, if approved. The commercial infrastructure for specialty oncology products typically consists of a targeted, specialty sales force that calls on a limited and focused group of physicians supported by sales management, internal sales support, an internal marketing group and distribution support. Additional capabilities important to the oncology marketplace include the management of key accounts such as managed care organizations, group-purchasing organizations, specialty pharmacies, oncology group networks and government accounts.

Based on the number of physicians who treat the lead oncology indications for CRLX101 and the size of competitive sales forces, we believe that we can effectively target the relevant U.S. market with a focused sales force. If CRLX101 is approved in multiple indications, we might need to increase the number of representatives. To develop the appropriate U.S. commercial infrastructure, we will have to invest significant amounts of financial and management resources.

In the future, we may utilize one or more strategic partners to optimally commercialize CRLX101 and our other products outside of the United States.

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export, of pharmaceutical products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources and the successful outcome of those processes cannot be guaranteed.

In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or FDCA, and implementing regulations. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or after approval may subject an applicant and/or sponsor to a variety of administrative or judicial sanctions, including refusal by the FDA to approve pending applications, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters and other types of letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement of profits, or civil or criminal investigations and penalties brought by the FDA and the Department of Justice or other governmental entities.

An applicant seeking approval to market and distribute a new drug product in the United States must typically undertake the following:

Nonclinical studies include laboratory evaluation of the purity and stability of the manufactured drug substance or active pharmaceutical ingredient and the formulated drug or drug product. They also include in vitro and animal studies to assess the safety and activity of the drug to start dose assessment for initial testing in humans and to further establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations. The results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical studies, among other things, are submitted to the FDA as part of an IND for clinical investigation in the United States. Some long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity, may continue after the IND is submitted.

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with IND and GCP requirements, which include, among other things, the requirement that all research subjects provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written study protocols detailing, among other things, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. A protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions related to a proposed clinical trial and places the trial on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin.

In addition, an IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol, major amendments and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health for public dissemination on their ClinicalTrials.gov website.

Human clinical trials are typically conducted in three sequential phases, which may overlap or be combined:

Phase 1: Phase 1 includes the initial introduction of an investigational new drug into humans. Phase 1 studies are typically closely monitored and may be conducted in patients or normal volunteer subjects. These studies are designed to determine the metabolism and pharmacologic actions of the drug in humans, the toxicities associated with increasing doses, and, if possible, to gain early evidence on effectiveness. During Phase 1, sufficient information about the drug’s pharmacokinetics and pharmacological effects should be obtained to permit the design of well-controlled, scientifically valid, Phase 2 studies. The total number of subjects and patients included in Phase 1 studies varies with the drug, but are generally smaller than later stage studies. Phase 1 studies also include studies of drug metabolism, structure-activity relationships, and mechanism of action in humans, as well as studies in which investigational drugs are used as research tools to explore biological phenomena or disease processes.

Phase 2: Phase 2 includes the controlled clinical studies conducted to evaluate the effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks associated with the drug. Phase 2 studies are typically well controlled, closely monitored, and conducted in a relatively small number of patients, usually involving no more than several hundred subjects.

Phase 3: Phase 3 studies are expanded trials, generally at geographically dispersed clinical trial sites. They are performed after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather the additional information about effectiveness and safety that is needed to evaluate the overall benefit-risk relationship of the drug and to provide an adequate basis for physician labeling. Phase 3 studies usually include from several hundred to several thousand subjects.

Phase 4. Post-approval studies may be conducted after initial marketing approval. These studies are used to gain additional experience from the treatment of patients in the intended therapeutic indication.

Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA through the IND and more frequently if serious adverse events occur. In addition, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the drug; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The FDA or the sponsor or the data monitoring committee may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted.

Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients

In order to protect the rights and welfare of human research subjects and to verify the quality and integrity of data submitted to the FDA in support of marketing applications, the FDA monitors all aspects of FDA-regulated research through a comprehensive program of on-site inspections and data audits. Under the FDA’s Bioresearch Monitoring Program, FDA field investigators and headquarters’ scientists conduct site visits of research sponsors, clinical investigators, contract research organizations, IRBs, radioactive drug research committees, and non-clinical (animal) laboratories.

In general, the FDA accepts foreign safety and efficacy studies that were not conducted under an IND provided that they are well designed, well conducted, performed by qualified investigators, and conducted in accordance with ethical principles acceptable to the world community. The conduct of these studies must meet at least minimum standards for assuring human subject protection. Therefore, for studies submitted in support of an NDA that were conducted outside the U.S. and not under an IND, the agency requires demonstration that such studies were conducted in accordance with Good Clinical Practices.

Expanded access, sometimes called “compassionate use,” is the use of investigational new drug products outside of clinical trials to treat patients with serious or immediately life-threatening diseases or conditions when there are no comparable or satisfactory alternative treatment options. The rules and regulations related to expanded access are intended to improve access to investigational drugs for patients who may benefit from investigational therapies.

When considering an IND application for expanded access to an investigational product with the purpose of treating a patient or a group of patients, the sponsor and treating physicians or investigators will determine suitability when all of the following criteria apply:

FDA regulations allow access to investigational drugs under an IND by the company or the treating physician (see investigator-sponsored trials below) for treatment purposes on a case-by-case basis for:

Investigator-sponsored trials are clinical trials where the investigator of the trial is also the “sponsor” of the trial for regulatory purposes. An “investigator” conducts clinical investigations and is the person under whose immediate direction the study drug is administered or dispensed to patients. A “sponsor” initiates and takes responsibility for a clinical investigation. A person who both initiates and conducts a clinical trial, and is responsible for all regulatory requirements, is designated as a “sponsor-investigator” by the FDA. Clinical investigators at academic medical centers who initiate clinical trials with a lawfully marketed drug to be used in a patient population or investigational (unapproved) indication often fit within this designation. In addition, as is the case with our investigator-sponsored trials, a company may provide a sponsor-investigator with supply of its unapproved product candidate and funding for the trial. Investigators who initiate and conduct such trials are responsible for obtaining an IND from the FDA and for ensuring compliance with the IND and associated regulatory requirements. As provided by the FDA’s regulations, the sponsor of a clinical trial is responsible for, among other things, selecting qualified investigators, providing them with the information they need to conduct the trial properly, ensuring proper monitoring of the trial, ensuring that the trial is conducted in accordance with the protocols contained in the IND, maintaining an effective IND with respect to the trial, and ensuring that the FDA, the company, and all participating investigators are promptly informed of significant new adverse effects or risks with respect to the drug. In contrast, in a company-sponsored trial, the pharmaceutical company whose drug will be studied is the sponsor of the trial and, as such, is responsible for ensuring compliance with all regulatory requirements, including obtaining the IND.

In connection with our ongoing investigator-sponsored trials of CRLX101, we have entered into agreements with the institutions at which the trials are being conducted. The terms of these agreements are customary and generally provide that (a) the institution is responsible for obtaining and maintaining any necessary IND for the trial, for conducting the trial in accordance with an agreed upon protocol and applicable regulatory requirements and for safety reporting to us, the IRB, and the FDA, (b) the institution grants to us a license to use the trial data for any legally permissible purpose and assigns to us all intellectual property rights relating to the trial drug developed during the course of the agreement, (c) we are responsible for supplying the trial drug and making agreed upon payments to the institution to fund the trial and (d) the term of the agreement is the duration of the applicable trial, however, the agreement can be terminated for convenience with notice, upon the request of an applicable regulatory agency, for safety reasons or following an uncured material breach by the other party.

Detailed information and results from preclinical and clinical studies and other requirements relating to the product’s chemistry, manufacture, controls and proposed labeling are submitted to the FDA as part of an NDA requesting approval to market the drug product for one or more indications. Under federal law, the submission of most NDAs is additionally subject to an application user fee, currently exceeding $2.3 million, and the sponsor of an approved NDA is also subject to annual product and establishment user fees, currently exceeding $114,000 per product and $585,000 per establishment for fiscal year 2016. These fees are typically increased annually. Important exceptions or waivers for user fees include:

The FDA conducts a preliminary review of an NDA within 60 days of its receipt and informs the sponsor by the 74th day after the FDA’s receipt of the submission to determine whether the application is 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 process of NDAs. “Standard review”, representing most such applications is generally reviewed within ten months from the date of filing. “Priority review”, as may be designated by the FDA for a drug that treats a serious condition and, if approved,

would provide a significant improvement in safety or effectiveness, are targeted to be reviewed within six months from the date of filing. The review process may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant to address an outstanding deficiency identified by the FDA following the original submission.

Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is or will be manufactured. These pre-approval inspections usually cover all facilities associated with an NDA submission, including drug component manufacturing (such as Active Pharmaceutical Ingredients), finished drug product manufacturing, and control testing laboratories. 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. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites meeting specific criteria to assure compliance with GCP. The FDA may also inspect the company to evaluate, for example, processes, safety reporting procedures, training and compliance with U.S. regulations as the sponsor.

In addition, as a condition of approval, the FDA may require an applicant to develop REMS. REMS use risk minimization strategies beyond the professional labeling to ensure that the benefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to use the product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential adverse events and whether the product is a new molecular entity. REMS can include medication guides, physician communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU may include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring and the use of patient registries. The FDA may require a REMS before approval or post-approval if it becomes aware of a serious risk associated with use of the product. The requirement for a REMS can materially affect the potential market and profitability of a product.

The FDA may refer an application for a novel drug to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

The FDA is authorized to designate certain products for expedited review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs are fast track designation, breakthrough therapy designation, intended to expedite drug development, and priority review designation, intended to expedite review and approval of an NDA.

Specifically, the FDA may designate a product for fast track review if it is intended, whether alone or in combination with one or more other drugs, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For fast track products, sponsors may have greater interactions with the FDA regarding drug development and the company may submit sections of a fast track product’s NDA before the application is complete. A rolling review must be communicated to and agreed upon by the FDA. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information. The sponsor must pay the applicable user fee upon submission of the first module in the rolling submission. However, the FDA’s time period goal for reviewing a rolling NDA does not begin until the last module of the NDA is submitted. Notably, 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 2012, Congress enacted the Food and Drug Administration Safety and Improvement Act, or FDASIA. This law established a new regulatory scheme allowing for expedited review of products designated as “breakthrough therapies.” A product may be designated as a breakthrough therapy if it is intended, either alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. The FDA may take certain actions with respect to breakthrough therapies, including holding increased meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross-disciplinary project lead for the review team; and taking other steps to design the clinical trials in an efficient manner. In oncology, new products with breakthrough therapy designation have occasionally been approved well before the PDUFA review timeline, even for priority review, has elapsed.

An NDA for a drug will receive priority review designation by the FDA if it is a drug that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA determines, on a case-by-case basis, whether the proposed drug represents a significant improvement when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-

limiting drug reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, and evidence of safety and effectiveness in a new subpopulation. A priority designation is intended to direct overall attention and resources to the evaluation of such applications, and to shorten the FDA’s goal for taking action on a marketing application from ten months to six months after the application is accepted for filing.

The FDA may grant accelerated approval to a drug for a serious or life-threatening condition that provides meaningful therapeutic advantage to patients over existing treatments based upon a determination that the drug has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit. The FDA may also grant accelerated approval for such a condition when the product has an effect on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality, or IMM, and that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Drugs granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.

For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug, such as an effect on IMM. The FDA has limited experience with accelerated approvals based on intermediate clinical endpoints, but has indicated that such endpoints generally may support accelerated approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a drug.

The accelerated approval pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a drug, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, accelerated approval has been used extensively in the development and approval of drugs for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large trials to demonstrate a clinical or survival benefit.

Accelerated approval will be subject to the requirement that the applicant study the drug further, to verify and describe its clinical benefit, where there is uncertainty as to the relation of the surrogate endpoint to clinical benefit, or of the observed clinical benefit to ultimate outcome. Post-marketing studies would usually be studies already underway. When required to be conducted, such studies must also be adequate and well-controlled. The applicant shall carry out any such studies with due diligence.

Failure to conduct required post-approval studies, or confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the drug from the market on an expedited basis. All promotional materials for drug candidates approved under accelerated regulations are subject to prior review by the FDA.

On the basis of the FDA’s evaluation of the NDA and accompanying information, including the results of the 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 product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require additional, sometimes substantial, 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.

If the FDA approves a product, it may impose post-marketing requirements, which are studies and clinical trials that the sponsor is required to conduct under one or more statutes or regulations, or post-marketing commitments which are studies or clinical trials that the sponsor has agreed to conduct, but that are not required by a statute or regulation. The FDA may limit the approved indications for use for the product, require that contraindications, warnings and/or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess the 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 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, many 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.

Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of adverse experiences with the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing, annual user fee requirements for any marketed products and the establishments at which such products are manufactured, as well as new application fees for supplemental applications with or without clinical data.

In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and state agencies, and are subject to periodic unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers that the sponsor may decide to use. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Drugs may be promoted only for the approved indications and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability.

In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act, or PDMA, and its implementing regulations, as well as the Drug Supply Chain Security Act, or DSCA, which regulate the distribution and tracing of prescription drugs and prescription drug samples at the federal level, and set minimum standards for the regulation of drug distributors by the states. The PDMA, its implementing regulations and state laws limit the distribution of prescription pharmaceutical product samples, and the DSCA imposes requirements to ensure accountability in distribution and to identify and remove counterfeit and other illegitimate products from the market.

In 1984, with passage of the Hatch-Waxman Amendments to the FDCA, Congress authorized the FDA to approve generic drugs that are the same as drugs previously approved by the FDA under the NDA provisions of the statute. To obtain approval of a generic drug, an applicant must submit an abbreviated new drug application, or ANDA, to the agency. In support of such applications, a generic manufacturer may rely on the preclinical and clinical testing previously conducted for a drug product previously approved under an NDA, known as the reference listed drug, or RLD.

Specifically, in order for an ANDA to be approved, the FDA must find that the generic version is identical to the RLD with respect to the active ingredients, the route of administration, the dosage form, and the strength of the drug. At the same time, the FDA

must also determine that the generic drug is “bioequivalent” to the innovator drug. Under the statute, a generic drug is bioequivalent to a RLD if “the rate and extent of absorption of the drug do not show a significant difference from the rate and extent of absorption of the listed drug[.]”

Upon approval of an ANDA, the FDA indicates whether the generic product is “therapeutically equivalent” to the RLD in its publication “Approved Drug Products with Therapeutic Equivalence Evaluations,” also referred to as the “Orange Book.” Physicians and pharmacists consider a therapeutic equivalent generic drug to be fully substitutable for the RLD. In addition, by operation of certain state laws and numerous health insurance programs, the FDA’s designation of therapeutic equivalence often results in substitution of the generic drug without the knowledge or consent of either the prescribing physician or patient.

Under the Hatch-Waxman Amendments, the FDA may not approve an ANDA until any applicable period of non-patent exclusivity for the RLD has expired. The FDCA provides a period of five years of non-patent data exclusivity for a new drug containing a new chemical entity. In cases where such exclusivity has been granted, an ANDA may not be filed with the FDA until the expiration of five years unless the submission is accompanied by a Paragraph IV certification, as discussed below, in which case the applicant may submit its application four years following the original product approval. The FDCA also provides for a period of three years of exclusivity if the NDA includes reports of one or more new clinical investigations, other than bioavailability or bioequivalence studies, that were conducted by or for the applicant and are essential to the approval of the application. This three-year exclusivity period often protects changes to a previously approved drug product, such as a new dosage form, route of administration, combination or indication.

Upon approval of an NDA or a supplement thereto, NDA sponsors are required to list with the FDA each patent with claims that cover the applicant’s product or an approved method of using the product. Each of the patents listed by the NDA sponsor is published in the Orange Book. When an ANDA applicant files its application with the FDA, the applicant is required to certify to the FDA concerning any patents listed for the reference product in the Orange Book, except for patents covering methods of use for which the ANDA applicant is not seeking approval. To the extent that the Section 505(b)(2) applicant is relying on studies conducted for an already approved product, the applicant is required to certify to the FDA concerning any patents listed for the approved product in the Orange Book to the same extent that an ANDA applicant would.

A certification that the new product will not infringe the already approved product’s listed patents or that such patents are invalid or unenforceable is called a Paragraph IV certification. If the applicant does not challenge the listed patents or indicates that it is not seeking approval of a patented method of use, the ANDA application will not be approved until all the listed patents claiming the referenced product have expired (other than method of use patents involving indications for which the ANDA applicant is not seeking approval).

If the ANDA applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days after the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA until the earlier of 30 months after the receipt of the Paragraph IV notice, expiration of the patent, or a decision in the infringement case that is favorable to the ANDA applicant.

Under the Pediatric Research Equity Act of 2003, a NDA or supplement thereto must contain data that are adequate to assess the safety and effectiveness of the drug product for the claimed indications in all relevant pediatric subpopulations, and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. With enactment of FDASIA in 2012, sponsors must also submit pediatric study plans prior to the assessment data. Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests, and other information required by regulation. The applicant, the FDA, and the FDA’s internal review committee must then review the

information submitted, consult with each other, and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or partial waivers from the pediatric data requirements. Additional requirements and procedures relating to deferral requests and requests for extension of deferrals are contained in FDASIA. Unless otherwise required by regulation, the pediatric data requirements do not apply to products with orphan designation.

The Best Pharmaceuticals for Children Act is intended to improve the FDA and applicant accountability for the agreed-upon pediatric studies by creating a new mechanism for funding pediatric studies that sponsors or holders of approved applications declined to conduct voluntarily. Pediatric exclusivity, if granted, provides for the attachment of an additional six months of marketing protection to the term of any existing regulatory exclusivity, including the non-patent and orphan exclusivity, which is discussed below. This six-month exclusivity may be granted if an NDA sponsor submits pediatric data that fairly respond to a written request from the FDA for such data. The data do not need to show the product to be effective in the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDA’s request, the additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA within the statutory time limits, whatever statutory or regulatory periods of exclusivity or patent protection that cover the product are extended by six months. This is not a patent term extension, but it effectively extends the regulatory period during which the FDA cannot approve another application.

In some oncology indications, where pediatric studies are impossible or highly impractical (because, for example, the number of pediatric patients is so small or geographically dispersed), it may be possible to request a waiver.

Under the Orphan Drug Act, the FDA may designate a drug product as an “orphan drug” if it is intended to treat a rare disease or condition (generally meaning that it affects fewer than 200,000 individuals in the United States. A company must request orphan product designation before submitting a NDA. If the request is granted, the FDA will disclose the identity of the therapeutic agent and its potential use. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product with orphan status receives the first FDA approval for the disease or condition for which it has such designation, the product generally will receive orphan product exclusivity. Orphan product exclusivity means that the FDA may not approve any other applications for the same product for the same indication for seven years, except in certain limited circumstances. Competitors may receive approval of different products for the indication for which the orphan product has exclusivity and may obtain approval for the same product but for a different indication. If a drug or drug product designated as an orphan product ultimately receives marketing approval for an indication broader than what was designated in its orphan product application, it may not be entitled to exclusivity.

Pharmaceutical companies developing an orphan drug to treat an uncommon disease may be eligible for the research tax credit for qualified research expenses or the orphan drug tax credit for development costs attributable to qualified clinical testing incurred in developing the drug.

Unless otherwise required by regulation, the pediatric data requirements under the Pediatric Research Equity Act do not apply to products with orphan designation.

A patent claiming a new drug product may be eligible for a limited patent term extension under the Hatch-Waxman Act, which permits a patent restoration of up to five years for patent term lost during product development and the FDA regulatory review. The restoration period granted is typically one-half the time between the effective date of an IND and the submission date of a NDA, plus the time between the submission date of a NDA and the ultimate approval date. Patent term restoration cannot be used to extend the remaining term of a patent past a total of 14 years from the product’s approval date. Only one patent applicable to an approved drug product is eligible for the extension, and the application for the extension must be submitted prior to the expiration of the patent in question. A patent that covers multiple drugs for which approval is sought can only be extended in connection with one of the approvals. The USPTO reviews and approves the application for any patent term extension or restoration in consultation with the FDA.

In order to market any product outside of the United States, a company must also comply with numerous and varying regulatory requirements of other countries and jurisdictions regarding quality, safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of drug products. Whether or not it obtains FDA approval for a product, the company would need to obtain the necessary approvals by the comparable foreign regulatory authorities before it can commence clinical trials or marketing of the product in those countries or jurisdictions. The approval process ultimately varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others.

Pursuant to the currently applicable Clinical Trials Directives, an applicant must obtain approval from the competent national authority of the EU member state in which the clinical trial is to be conducted. If the clinical trial is conducted in different EU member states, the competent authorities in each of these EU member states must provide their approval for the conduct of the clinical trial. Furthermore, the applicant may only start a clinical trial at a specific study site after the competent ethics committee has issued a favorable opinion. In April 2014, the EU adopted a new Clinical Trials Regulation, which is set to replace the current Clinical Trials Directive. The new Clinical Trials Regulation will be directly applicable to and binding in all 28 EU member states without the need for any national implementing legislation, and will become applicable no earlier than May 28, 2016. Under the new coordinated procedure for the approval of clinical trials, the sponsor of a clinical trial will be required to submit a single application for approval of a clinical trial to a reporting EU member state through an EU Portal. The submission procedure will be the same irrespective of whether the clinical trial is to be conducted in a single EU member state or in more than one EU member state. The Clinical Trials Regulation also aims to streamline and simplify the rules on safety reporting for clinical trials.

To obtain marketing approval of a drug under EU regulatory systems, an applicant must submit a marketing authorization application, or MAA, using the appropriate registration procedure.

The “centralized procedure” provides for the grant of a single marketing authorization by the European Commission that is valid for all European Union member states. The centralized procedure is compulsory for specific products, including for medicines produced by certain biotechnological processes, products designated as orphan medicinal products, advanced therapy products and products with a new active substance indicated for the treatment of certain diseases. The working definition includes all malignant and borderline malignant neoplasms, following the current International Classification of Diseases for Oncology, including primary or secondary malignant neoplasms, carcinoma in situ, and neoplasms classified as uncertain whether benign or malignant. Medicinal products for cancer treatment include antineoplastic agents (including modulators and enhancers of antineoplastic activity) and adjuvant treatments. For products with a new active substance indicated for the treatment of other diseases and products that are highly innovative or for which a centralized process is in the interest of patients, the centralized procedure may be optional.

The Committee for Medicinal Products for Human Use, or CHMP, is responsible for preparing EMA’s opinions on all questions concerning medicines for human use, in accordance with European regulation. In the centralized procedure, the CHMP is responsible for conducting the initial assessment of medicines for which an EU-wide marketing authorization is sought. The maximum timeframe for the evaluation of an MAA is 210 days, excluding clock stops, when additional information or written or oral explanation is to be provided by the applicant in response to questions of the CHMP. Accelerated evaluation might be granted by the CHMP in exceptional cases, when a medicinal product is of major interest from the point of view of public health and in particular from the viewpoint of therapeutic innovation. In this circumstance, the EMA ensures that the opinion of the CHMP is given within 150 days.

The CHMP is also responsible for several post-authorization and maintenance activities, such as the assessment of modifications or extensions to an existing marketing authorization.

In the EU, new chemical entities qualify for eight years of data exclusivity upon marketing authorization and an additional two years of market exclusivity. This data exclusivity, if granted, prevents regulatory authorities in the EU from referencing the innovator’s data to assess a generic (abbreviated) application for eight years, after which generic marketing authorization can be submitted, and the innovator’s data may be referenced, but not approved for two years. The overall ten-year period will be extended to a maximum of eleven years if, during the first eight years of those ten years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. Even if a compound is considered to be a new chemical entity and the sponsor is able to gain the prescribed period of data exclusivity, another company nevertheless could also market another version of the drug if such company can complete a full MAA with a complete database of pharmaceutical test, preclinical tests and clinical trials and obtain marketing approval of its product.

Significant uncertainty exists as to the coverage and reimbursement status of products approved by the FDA and other government authorities. Sales of products 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 in the United States such as Medicare and Medicaid, commercial health insurers and managed care organizations. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third-party payors may limit coverage to specific products on an approved list, or formulary, which might not include all of the approved products for a particular indication.

In order to secure coverage and reimbursement for any product that might be approved for sale, a company may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the product, in addition to the costs required to obtain FDA or other comparable regulatory approvals. A payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Third-party reimbursement may not be sufficient to maintain price levels high enough to realize an appropriate return on investment in product development.

In the EU pricing and reimbursement schemes vary widely from country to country. Some countries provide that drug products may be marketed only after a reimbursement price has been agreed. Some countries may require the completion of additional studies that compare the cost-effectiveness of a particular drug candidate to currently available therapies. For example, the EU provides options for its member states to restrict the range of drug products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. EU member states may approve a specific price for a drug product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the drug product on the market. Other member states allow companies to fix their own prices for drug products, but monitor and control company profits. The downward pressure on health care costs in general, particularly prescription drugs, has become intense. As a result, increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross-border imports from low-priced markets exert competitive pressure that may reduce pricing within a country. Any country that has price controls or reimbursement limitations for drug products may not allow favorable reimbursement and pricing arrangements.

Healthcare providers, physicians and third-party payors play a primary role in the recommendation and prescription of drug products that are granted marketing approval. Arrangements with third-party payors and customers are subject to broadly applicable fraud and abuse and other healthcare laws and regulations. Such restrictions under applicable federal and state healthcare laws and regulations, include the following:

Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug manufacturers to report information related to payments to physicians and other health care providers or marketing expenditures. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

As of February 1, 2016, we had 47 full-time employees, including a total of 17 employees with M.D. or Ph.D. degrees. Of our workforce, 22 employees are engaged in research and development. None of our employees is represented by labor unions or covered by collective bargaining agreements.

We file reports and other information with the Securities and Exchange Commission, or SEC, as required by the Securities Exchange Act of 1934, as amended, which we refer to as the Exchange Act. You can find, copy and inspect information we file at the SEC’s public reference room, which is located at 100 F Street, N.E., Room 1580, Washington, DC 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the SEC’s public reference room. You can review our electronically filed reports and other information that we file with the SEC on the SEC’s web site at http://www.sec.gov.

Our Internet website is http://www.ceruleanrx.com. We make available free of charge through our website our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Sections 13(a) and 15(d) of the Exchange Act. We make these reports available through our website as soon as reasonably practicable after we electronically file such reports with, or furnish such reports to, the SEC. In addition, we regularly use our website to post information regarding our business, product development programs and governance, and we encourage investors to use our website, particularly the information in the section entitled “Investors,” as a source of information about us.

The foregoing references to our website are not intended to, nor shall they be deemed to, incorporate information on our website into this Annual Report on Form 10-K by reference.

Our business is subject to numerous risks. The following important factors, among others, could cause our actual results to differ materially from those expressed in forward-looking statements made by us or on our behalf in this Annual Report on Form 10-K and other filings with the Securities and Exchange Commission, or SEC, press releases, communications with investors and oral statements. Actual future results may differ materially from those anticipated in our forward-looking statements. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

We will need substantial additional funding. If we are unable to raise capital when needed, we could be forced to delay, reduce or eliminate our product development programs or commercialization efforts.

We expect our expenses to increase in connection with our ongoing activities, particularly as we advance the clinical development of CRLX101 and CRLX301 and continue research and development and initiate additional clinical trials of, and seek regulatory approval for, these and other future product candidates. In addition, if we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. In particular, the costs that may be required for the manufacture of any product candidate that receives marketing approval may be substantial, and manufacturing our nanoparticle-drug conjugates, or NDCs, for commercial sale will require expensive and specialized facilities, processes and materials. Furthermore, relative to previous years when we operated as a private company, we expect to incur significant additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or any future commercialization efforts.

We plan to use our current cash and cash equivalents to fund our ongoing research and development efforts. We will be required to expend significant funds in order to advance development of CRLX101, CRLX301 and our other potential product candidates. Our existing cash and cash equivalents will not be sufficient to fund all of the efforts that we plan to undertake, such as additional randomized trials of CRLX101 or CRLX301. Accordingly, we will be required to obtain further funding through public or private equity offerings, debt financings, collaborations or licensing arrangements or other sources. Adequate and additional funding may not be available to us on acceptable terms or at all.

On January 8, 2015 we entered into a loan and security agreement, which we refer to as the Hercules Loan Agreement, with Hercules Technology Growth Capital, Inc., or Hercules, and drew the first tranche of $15.0 million under the Hercules Loan Agreement. On November 24, 2015, we drew a second tranche of $6.0 million under the Hercules Loan Agreement. We elected not to commence a randomized Phase 2 clinical trial of CRLX101 in combination with chemoradiotherapy on or prior to December 15, 2015, which was a condition of obtaining an additional tranche in an amount of up to $5.0 million. As a result, we are no longer eligible to borrow this amount under the Hercules Loan Agreement.

If we elect to obtain any additional debt financing, our ability to do so may be limited by covenants we have made under the Hercules Loan Agreement and our pledge to Hercules of substantially all of our assets, other than our intellectual property, as collateral. We have also granted Hercules a negative pledge with respect to our intellectual property, which, among other things, prohibits us from selling, transferring, assigning, mortgaging, pledging, leasing, granting a security interest in or otherwise encumbering our intellectual property. This negative pledge could further limit our ability to obtain additional debt financing. Our failure to raise capital as and when needed would have a negative impact on our financial condition and our ability to pursue our business strategy.

On April 10, 2015 we closed an underwritten public offering, or the Secondary Offering, of 6,716,000 shares of common stock, including 876,000 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $6.00 per share. The gross proceeds to us from the Secondary Offering were approximately $40.3 million, before deducting underwriting discounts and commissions and offering expenses payable by us.

We believe that our cash and cash equivalents as of December 31, 2015 will enable us to fund our operating expenses, debt service and scheduled capital expenditures for at least twelve months from our 2015 financial statement issuance date. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. Our future capital requirements will depend on many factors, including:

Identifying potential product candidates and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain regulatory approval and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of products that we do not expect to be commercially available for several years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to technologies or product candidates.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of public or private equity offerings, debt financings, license and development agreements with collaboration partners or other sources. In addition, we may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders may be materially diluted, and the terms of such securities could include liquidation or other preferences that adversely affect the rights of our existing stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include restrictive covenants that limit our ability to take specified actions, such as incurring additional debt, making capital expenditures or declaring dividends. In addition, additional debt financing would result in increased fixed payment obligations.

If we raise funds through collaborations, strategic partnerships or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Our existing and any future indebtedness could adversely affect our ability to operate our business.

On January 8, 2015, we entered into the Hercules Loan Agreement and drew the first tranche of $15.0 million. We used $3.6 million of the proceeds from our draw under the Hercules Loan Agreement to repay in full our outstanding indebtedness under our loan and security agreement with Lighthouse Capital Partners VI, L.P. On November 24, 2015 we drew an additional tranche of $6.0 million under the Hercules Loan Agreement. As of December 31, 2015, we had approximately $22.5 million in outstanding indebtedness under the Hercules Loan Agreement.

Our outstanding indebtedness combined with current and future financial obligations and contractual commitments, including any additional indebtedness beyond our borrowings from Hercules, could have significant adverse consequences, including:

We intend to satisfy our current and future debt service obligations with our existing cash and cash equivalents. Nevertheless, we may not have sufficient funds, and may be unable to arrange for additional financing, to pay the amounts due under our existing debt instruments. Failure to make payments or comply with other covenants under our existing debt instruments could result in an event of default and acceleration of amounts due. If an event of default occurs and Hercules accelerates the amounts due, we may not be able to make accelerated payments, and Hercules could seek to enforce security interests in the collateral securing such indebtedness, which includes substantially all of our assets other than our intellectual property.

We have incurred significant losses since incorporation. We expect to incur losses over the next several years and may never achieve or maintain profitability.

Since incorporation, we have incurred significant operating losses. As of December 31, 2015, we had an accumulated deficit of $161.4 million. We do not know whether or when we will become profitable. We have not generated any revenues to date from product sales and have financed our operations primarily through public offerings of our common stock, private placements of our preferred stock, convertible debt financings and secured debt financings. We have not completed development of any product candidate and have devoted substantially all of our financial resources and efforts to research and development, including preclinical studies and clinical trials. We expect to continue to incur significant expenses and operating losses over the next several years. Our net losses may fluctuate significantly from quarter to quarter and year to year. Net losses and negative cash flows have had, and will continue to have, an adverse effect on our stockholders deficit and working capital. We anticipate that our expenses will increase substantially if and as we:

To become and remain profitable, we must succeed in developing and eventually commercializing products that generate significant revenue. We do not expect to generate significant revenue unless and until we are able to obtain marketing approval for, and successfully commercialize, one or more of our product candidates. This will require us to be successful in a range of challenging activities, including completing preclinical testing and clinical trials of our product candidates, discovering additional product

candidates, obtaining regulatory approval for these product candidates, manufacturing, marketing and selling any products for which we may obtain regulatory approval, satisfying any post-marketing requirements and obtaining reimbursement for our products from private insurance or government payors. We are only in the preliminary stages of most of these activities and have not yet commenced other of these activities. We may never succeed in these activities and, even if we do, may never generate revenues that are significant enough to achieve profitability.

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to accurately predict the timing or amount of increased expenses or when, or if, we will be able to achieve profitability. If we are required by the United States Food and Drug Administration, or FDA, or the European Medicines Agency, or EMA, to perform studies in addition to those currently expected, or if there are any delays in completing our clinical trials or the development of any of our product candidates, our expenses could increase.

Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would depress the value of our company and could impair our ability to raise capital, expand our business, maintain our research and development efforts, diversify our product offerings or even continue our operations. A decline in the value of our company could cause our stockholders to lose all or part of their investment.

Given our planned expenditures for the next several years, including, without limitation, expenditures in connection with our clinical trials of CRLX101 and CRLX301, our independent registered public accounting firm may conclude that there is substantial doubt regarding our ability to continue as a going concern.

We have a limited operating history and no history of commercializing pharmaceutical products, which may make it difficult to evaluate the prospects for our future viability.

Our operations to date have been limited to organizing and staffing our company, developing and securing our technology, raising capital and undertaking preclinical studies and clinical trials of our product candidates. We have not yet demonstrated the ability to successfully complete development of any product candidates, obtain marketing approvals, manufacture a commercial scale product, or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, any predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing pharmaceutical products.

Assuming we obtain marketing approval for any of our product candidates, we will need to transition from a company with a research and development focus to a company capable of supporting commercial activities. We may encounter unforeseen expenses, difficulties, complications and delays and may not be successful in such a transition.

Risks Related to the Discovery, Development and Commercialization of Our Product Candidates

Our approach to the discovery and development of product candidates based on our Dynamic Tumor Targeting Platform is unproven, and we do not know whether we will be able to develop any products of commercial value.

We are focused on applying our proprietary Dynamic Tumor Targeting Platform to develop drugs that address serious unmet medical needs. We believe that our Dynamic Tumor Targeting Platform has the potential to create drugs that may have significant utility in several cancer indications, particularly in combination with other cancer therapies. While the results of preclinical studies and early-stage clinical trials have suggested that certain of our product candidates may have such utility, we have not yet succeeded and may not succeed in demonstrating efficacy and safety for any of our product candidates in later stage clinical trials or in obtaining marketing approval thereafter. For example, we have not yet advanced a compound beyond Phase 2 clinical development. Moreover, the only compound for which we have completed a Phase 2 clinical trial, CRLX101 for the potential treatment of patients with advanced non-small cell lung cancer, or NSCLC, who had progressed through one or two prior regimens of chemotherapy, failed to meet its primary endpoint of improvement in overall survival.

In addition, we have never had a product candidate receive approval or clearance from the FDA or a non-U.S. regulatory authority. While the FDA has approved nanoparticles such as Doxil® (doxorubicin hydrochloride liposome injection) and Abraxane® (nab-paclitaxel), to our knowledge, the FDA has not yet approved a polymeric nanoparticle such as our NDCs, which are a new way of targeting tumors. The regulatory review process for novel product candidates, such as ours, can be more expensive and take longer than for product candidates based on more well-known or extensively studied technologies due to regulatory authorities’ lack of experience with them. As a result, we may be required to conduct additional studies and/or trials beyond those we anticipate and it may take us longer to develop and/or obtain regulatory approval for our existing and any future product candidates than we expect.

We are particularly dependent on the success of our lead product candidate, CRLX101, and our ability to develop, obtain marketing approval for and successfully commercialize CRLX101. If we are unable to develop, obtain marketing approval for or successfully commercialize CRLX101, either alone or through a collaboration, or experience significant delays in doing so, our business could be materially harmed.

We currently have no products approved for sale and have invested a significant portion of our efforts and financial resources in the development of CRLX101 for the treatment of patients with inadequately treated forms of cancer. Our prospects are substantially dependent on our ability to develop, obtain marketing approval for and successfully commercialize CRLX101. The success of CRLX101 will depend, among other things, on our ability to successfully complete clinical trials of CRLX101. The clinical trial process is uncertain, and failure of one or more clinical trials can occur at any stage of testing. For example, in 2011, we initiated an open-label, randomized Phase 2 clinical trial of CRLX101 as monotherapy in patients with advanced NSCLC who had progressed through one or two prior regimens of chemotherapy. In this Phase 2 clinical trial, CRLX101 failed to meet its primary endpoint of improvement in overall survival of the CRLX101-treated group as compared to the control arm of the study, which was best supportive care.

In addition to the successful completion of clinical trials, the success of CRLX101 will also depend on several other factors, including the following:

If we are unable to develop, receive marketing approval for, or successfully commercialize CRLX101, or experience delays as a result of any of these factors or otherwise, our business could be materially harmed.

If we experience delays or difficulties in the enrollment of patients in clinical trials, we may not achieve our clinical development on our anticipated timeline, or at all, and our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or continue clinical trials for CRLX101 or any of our other product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in clinical trials. Patient enrollment is a significant factor in the timing of clinical trials, and is affected by many factors, including:

Our inability to enroll a sufficient number of patients for our clinical trials could result in significant delays or may require us to abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result in increased development costs for our product candidates, delay or halt the development of and approval processes for our product candidates and jeopardize our ability to achieve our clinical development timeline and goals, including the dates by which we will commence, complete and receive results from clinical trials. Enrollment delays may also delay or jeopardize our ability to commence sales and generate revenues from our product candidates. Any of the foregoing could cause the value of our company to decline and limit our ability to obtain additional financing, if needed.

The FDA and other regulatory agencies may require more extensive or expensive trials for our combination product candidates than may be required for single agent pharmaceuticals.

To obtain regulatory approval for a combination product candidate, the FDA typically requires an applicant to show that each active ingredient in an investigational combination drug candidate makes a contribution to the combined investigational drug candidate’s claimed effects and that the dosage of each component, including amount, frequency and duration, is such that the combination is safe and effective for a significant patient population requiring such concurrent therapy. This could require us to conduct more extensive and more expensive clinical trials than would be the case for a single agent pharmaceutical. As a result, the need to conduct such trials could make it more difficult and costly to obtain regulatory approval of our combination drug product candidate than of a new drug containing only a single active pharmaceutical ingredient.

We are currently pursuing the clinical development of CRLX101 in combinations with other drugs. For example, we are exploring combinations with Avastin in relapsed renal cell carcinoma and relapsed ovarian cancer. If the FDA revokes its approval of, or if safety, efficacy, manufacturing or supply issues arise with, Avastin or any other therapeutic that we use in combination with CRLX101 in the future, we may be unable to market CRLX101 or may experience significant regulatory delays or supply shortages, and our business could be materially harmed.

If the FDA revokes its approval of Avastin, or any other approved therapeutic that we intend to use in combination therapy with CRLX101, then we will not be able to market CRLX101 in combination with that agent. If safety or efficacy issues arise with such combination agent, we may experience significant regulatory delays, and the FDA may require us to redesign or terminate the applicable clinical trials. Moreover, if Avastin, or another potential combination agent for CRLX101, for instance, were to receive regulatory approval in combination with a different therapeutic in any indication for which we are pursuing approval, such approval could impact the feasibility and design of any subsequent clinical trials that we may seek to conduct evaluating CRLX101 in combination with such agent. In addition, if manufacturing, cost or other issues result in a supply shortage of Avastin or any other combination agent, we may not be able to complete clinical development of CRLX101 on our current timeline or at all.

Even if CRLX101 were to receive regulatory approval and be commercialized for use in combination with an approved combination agent, we would continue to be subject to the risk that the FDA could revoke its approval of such agent, that safety, efficacy, manufacturing, cost or supply issues could arise with one of these therapeutic agents. This could result in CRLX101 being removed from the market or being less successful commercially.

If our hypothesis regarding the role of hypoxia inducible factor, or HIF, in cancer cells proves incorrect, it may adversely affect our ability to commercialize and market CRLX101.

We believe that the anti-cancer activity shown by CRLX101 in preclinical tumor models is due in part to its inhibition of HIF, and we have prioritized the clinical development of CRLX101, among other criteria, on HIF-driven tumor types. In support of this hypothesis in November 2015 we announced at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics that we have shown that CRLX101 inhibits carbonic anhydrase 9 in patient tumors, considered to be a sensor of HIF-1α. This clinical evidence is consistent with our preclinical data. While HIF-1α has become a target of increasing interest in cancer

research and recent research suggests that HIF-1α is a master regulator for many cancer cell survival pathways, the science underlying HIF-1α is based on recent discoveries and not fully understood. Moreover, the exact role of HIF-2α is less well described and understood. If our hypothesis with respect to the role of HIF in cancer cells proves incorrect, CRLX101 may not have the same level of therapeutic benefit as it might otherwise have, and in that case we may be unable to receive marketing approval for, or successfully commercialize, CRLX101, and our business could be materially harmed.

Clinical drug development involves a lengthy and expensive process with an uncertain outcome. We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our product candidates.

Two of our product candidates are in clinical development, all of our other potential product candidates are in preclinical development, and the risk of failure of all of our product candidates is high. It is impossible to predict when or if any of our product candidates will prove effective or safe in humans or will receive regulatory approval. Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, we must complete preclinical development and then conduct extensive clinical trials to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. A failure of one or more clinical trials can occur at any stage of testing. The clinical development of our product candidates is susceptible to the risk of failure inherent at any stage of drug development, including failure to have a sufficient quantity of our product candidate available when needed, failure to demonstrate efficacy in a clinical trial or across a broad population of patients, the occurrence of severe or medically or commercially unacceptable adverse events, failure to comply with protocols or applicable regulatory requirements and determination by the FDA or any comparable non-U.S. regulatory authority that a drug product is not approvable. It is possible that even if one or more of our product candidates has a beneficial effect, that effect will not be detected during clinical evaluation as a result of one or more of a variety of factors, including the size, duration, dose, dosing schedule, design, measurements, conduct or analysis of our clinical trials. Conversely, as a result of the same factors, our clinical trials may indicate an apparent positive effect of a product candidate that is greater than the actual positive effect, if any. Similarly, in our clinical trials, we may fail to detect toxicity of or intolerability caused by our product candidates, or mistakenly believe that our product candidates are toxic or not well tolerated when that is not in fact the case.

The outcome of preclinical studies and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a clinical trial do not necessarily predict final results. For example, although a Phase 1/2a clinical trial of CRLX101 supported advancement of CRLX101 as monotherapy into Phase 2 clinical trials for patients with advanced NSCLC who had progressed through one or two prior regimens of chemotherapy, CRLX101 failed to meet its primary endpoint of improvement in overall survival of patients in this indication. Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials after achieving positive results in earlier development, and we cannot be certain that we will not face additional setbacks. For example, although the results of the Phase 1b/2 single-arm IST of CRLX101 in patients with relapsed RCC supported our hypothesis that CRLX101 in combination with Avastin may be effective in this setting, there is no assurance that the RCC Trial will meet its endpoint or further support our registration strategy for CRLX101 in RCC. Moreover, there are currently multiple open-label ISTs of CRLX101 ongoing, including a Phase 2 open-label IST in patients with relapsed ovarian cancer, consisting of a single-arm trial of CRLX101 as monotherapy and a single-arm combination trial of CRLX101 and Avastin; and a Phase 1b/2 open-label IST of CRLX101 in combination with chemoradiotherapy in patients with locally advanced rectal cancer. Interim investigator-reported data from subsets of the total patient populations in certain of these ISTs have been reported. These ISTs are still in progress and final results are not yet available. The preliminary results reported from the ISTs have in some cases been observed in only a small number of patients and may not be achieved by other patients on these or other clinical trials. There can be no assurance that company-sponsored trials will confirm the data seen in the ISTs.

The design of a clinical trial can determine whether its results will support approval of a product, and flaws in the design of a clinical trial may not become apparent until the clinical trial is well advanced or completed and protocol amendments, if any, to address such flaws may not be sufficiently timely or corrective. We have limited experience in designing clinical trials and may be unable to design and execute a clinical trial to support marketing approval. For example, we believe that a significant increase in pathologic complete response may be a clinically meaningful endpoint for the treatment of locally advanced rectal cancer, but there can be no assurance that the FDA will agree. Moreover, no drug has yet been approved in this setting.

In addition, for several reasons it may become more challenging to design a timely, successful Phase 3 clinical trial for CRLX101 for patients with RCC. These factors include differences in the design requirements for a Phase 3 trial as compared to a Phase 2 trial and recent product approvals in this indication, which are significantly impacting the standard of care, as well as the regulatory thresholds for approval in RCC.

Another challenge is that preclinical and clinical data are often susceptible to varying interpretations and analyses. Many companies that believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval for the product candidates. Even if we believe that the results of clinical trials for our product candidates warrant marketing approval, the FDA or comparable non-U.S. regulatory authorities may disagree and may not grant marketing approval of our product candidates.

In some instances, there can be significant variability in safety or efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial procedures set forth in protocols, differences in the size, type and disease progression of the patient populations, changes in and adherence to the clinical trial protocols, variability in the quality of clinical supply batches and the rate of dropout among clinical trial participants. Any Phase 2, Phase 3 or other clinical trials that we may conduct may not demonstrate the efficacy and safety necessary to obtain regulatory approval to market our product candidates.

If we experience any of a number of possible unforeseen events in connection with clinical trials of our product candidates, potential marketing approval or commercialization of our product candidates could be delayed or prevented.

We may experience numerous unforeseen events during, or as a result of, clinical trials that could delay or prevent marketing approval of our product candidates, including:

Product development costs for us will increase if we experience delays in testing or pursuing marketing approvals and we may be required to obtain additional funds to complete clinical trials and prepare for possible commercialization of our product candidates. We do not know whether any preclinical tests or clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. Significant preclinical or clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize our product candidates and may harm our business and results of operations. In addition, many of the factors that cause, or lead to, clinical trial delays may ultimately lead to the denial of marketing approval of any of our product candidates.

We have conducted and intend to conduct additional clinical trials for certain of our product candidates at sites outside the United States, and the FDA may not accept data from trials conducted in such locations.

We have conducted, currently are conducting and intend in the future to conduct, clinical trials outside the United States. Opening trial sites outside the United States may involve additional regulatory, administrative and financial burdens, including compliance with foreign and local requirements relating to regulatory submission and clinical trial practices. For example, in late 2014, we commenced in Australia the Phase 1 portion of a Phase 1/2a clinical trial of CRLX301 in patients with advanced solid tumor malignancies. In addition, in the first half of 2015, we expanded the RCC Trial to South Korea where we opened five additional clinical sites. We expect to continue to conduct clinical trials of our product candidates at sites outside the U.S.

Although the FDA may accept data from clinical trials conducted outside the United States, acceptance of this data is subject to certain conditions imposed by the FDA. For example, the clinical trial must be well designed and conducted and performed by qualified investigators in accordance with good clinical practices, including review and approval by an independent ethics committee and informed consent from trial patients. The trial population must also adequately represent the U.S. population, and the data must be applicable to the U.S. population and U.S. medical practice in ways that the FDA deems clinically meaningful. Generally, the patient population for any clinical trials conducted outside the United States must be representative of the population for which we intend to seek approval in the United States. In addition, while these clinical trials are subject to the applicable local laws, FDA acceptance of the data will be dependent upon its determination that the trials also complied with all applicable U.S. laws and regulations. Nonetheless, there can be no assurance that the FDA will accept data from trials conducted outside the United States. If the FDA does not accept the data from our Phase 1/2a clinical trial of CRLX301 in Australia, for example, or any other trial that we conduct outside the United States, it would likely result in the need for additional clinical trials, which would be costly and time-consuming and delay or permanently halt our development of CRLX101, CRLX301 or any future product candidates.

In addition, the conduct of clinical trials outside the United States could have a significant impact on us. Risks inherent in conducting international clinical trials include:

If clinical trials of our product candidates fail to demonstrate safety and efficacy to the satisfaction of the FDA and comparable non-U.S. regulators, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of these product candidates.

We are not permitted to commercialize, market, promote or sell any product candidate in the United States without obtaining marketing approval from the FDA. Comparable non-U.S. regulatory authorities, such as the EMA, impose similar restrictions. We may never receive such approvals. We must complete extensive preclinical development and clinical trials to demonstrate the safety and efficacy of our product candidates in humans before we will be able to obtain these approvals.

Clinical testing is expensive, difficult to design and implement, can take many years to complete and is inherently uncertain as to outcome. We have not previously submitted a new drug application, or an NDA, to the FDA or similar drug approval filings to comparable non-U.S. regulatory authorities for any of our product candidates.

Any inability to successfully complete preclinical and clinical development could result in additional costs to us and impair our ability to generate revenues from product sales, regulatory and commercialization milestones and royalties. In addition, if (1) we are required to conduct additional or different clinical trials or preclinical testing of our product candidates beyond the trials and testing that we contemplate, (2) we are unable to successfully complete clinical trials or preclinical testing of our product candidates, (3) the results of these trials or tests are unfavorable, incomplete or inconclusive, or (4) there are unacceptable safety concerns associated with our product candidates, we, in addition to incurring additional costs, may:

A fast track designation by the FDA may not actually lead to a faster development or regulatory review or approval process.

In April 2015 we received fast track designation for CRLX101 for the treatment of metastatic RCC following progression through two or three prior lines of therapy. We may seek fast track designation for other indications or other product candidates. If a drug is intended for the treatment of a serious or life-threatening condition and the drug demonstrates the potential to address unmet medical needs for this condition, the drug sponsor may apply for FDA fast track designation. The FDA has broad discretion whether or not to grant this designation, so even if we believe a particular product candidate is eligible for this designation, the FDA may still decide not to grant it. Even if we do receive fast track designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. The FDA may withdraw fast track designation if it believes that the designation is no longer supported by data from or stated intentions of our clinical development program.

A breakthrough therapy designation by the FDA for our product candidates may not lead to a faster development or regulatory review or approval process, and it does not increase the likelihood that our product candidates will receive marketing approval.

We may seek a breakthrough therapy designation for some of our product candidates. A breakthrough therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. For drugs and biologics that have been designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. Drugs designated as breakthrough therapies by the FDA are also eligible for accelerated approval.

Designation as a breakthrough therapy is within the discretion of the FDA. Accordingly, even if we believe one of our product candidates meets the criteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to make such designation. In any event, the receipt of a breakthrough therapy designation for a product candidate may not result in a faster development process, review or approval compared to drugs considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. In addition, even if one or more of our product candidates qualifies as a breakthrough therapy, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

If we fail to obtain or maintain orphan drug exclusivity for some of our product candidates, we will miss out on certain valuable incentives including a period of marketing exclusivity as well as federal grants, tax credits and a waiver of Prescription Drug User Fee Act filing fees.

We intend to develop some product candidates that may be eligible for orphan drug designation from the FDA. Under the Orphan Drug Act, the FDA has discretion to designate a product as an orphan drug if it is designed to treat a rare disease or condition, which is defined as a patient population of less than 200,000 in the United States. The applicant that first obtains FDA approval for a designated orphan drug receives marketing exclusivity for use of that drug for the stated condition or disease for a period of seven years and becomes eligible for certain federal grants, tax credits and a waiver of Prescription Drug User Fee Act filing fees.

For our product candidates that are eligible, we plan to rely on the exclusivity period under the Orphan Drug Act to attain a competitive position. If we do not obtain orphan drug exclusivity for our drug products that do not have broad patent protection, our competitors may then sell the same drug to treat the same condition and our revenues will be reduced. In May 2015, the FDA granted orphan drug designation to CRLX101 for the treatment of ovarian cancer.

Even though we have obtained orphan drug designation for CRLX101 for the treatment of ovarian cancer, we still may not be the first to obtain marketing approval for any particular orphan indication. Further, even if we obtain orphan drug exclusivity for a product candidate, that exclusivity may not effectively protect it from competition because different drugs can be approved for the same condition. Even after an orphan drug is approved and granted orphan drug exclusivity, the FDA can subsequently approve the same drug for the same condition. Orphan drug designation neither shortens the development time or regulatory review time of a drug, nor gives the drug any advantage in the regulatory review or approval process.

We may request Priority Review for one or more of our product candidates at the time of the submission of the NDA to the FDA. The FDA may not grant Priority Review for any of our product candidates. Moreover, even if the FDA designated Priority Review for one of our product candidates, that designation may not lead to a faster regulatory review or approval process and, in any event, would not assure FDA approval.

A ten-month standard NDA review clock will begin at the conclusion of the 60 calendar day filing review period that starts on the date the FDA receives the original submission. This means the FDA has a total of twelve months from its receipt of the original submission to take regulatory action. We may be eligible for Priority Review designation for our NDA submission if the FDA determines that our product candidate treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The six-month Priority Review clock will begin at the conclusion of the 60 calendar day filing review period that starts on the date of FDA receipt of the original submission. Therefore, if granted Priority Review, the FDA has a total of eight months to take action on an application rather than the standard total of twelve months. We may request Priority Review for CRLX101 if and when we submit an NDA for CRLX101. Our current clinical development programs in areas of unmet medical need assume CRLX101 and/or CRLX301 will receive Priority Review. The FDA has broad discretion whether or not to grant Priority Review to a product candidate, so even if we believe a particular product candidate is eligible for such designation or status, the FDA may decide not to grant it. Thus, while the FDA has granted Priority Review to other oncology product candidates, CRLX101 or CRLX301 may not receive similar designation. Moreover, even if one of our product candidates is designated for Priority Review, such a designation does not necessarily mean a faster regulatory review process or necessarily confer any advantage with respect to approval compared to conventional FDA procedures. Receiving Priority Review from the FDA also does not guarantee approval within the eight-month review cycle or thereafter.

We believe we may in some instances be able to secure approval from the FDA or comparable non-U.S. regulatory authorities to use accelerated registration pathways. If unable to obtain such approval, we may be required to conduct additional preclinical studies or clinical trials beyond those that we contemplate, which could increase the expense of obtaining, and delay the receipt of, necessary marketing approvals.

We anticipate that we may seek an Accelerated Approval development pathway for certain indications for our product candidates. Under the Accelerated Approval provisions in the Federal Food, Drug, and Cosmetic Act, or FDCA, and the FDA’s implementing regulations, the FDA may grant Accelerated Approval to a product designed to treat a serious or life-threatening

condition that provides meaningful therapeutic benefit over available therapies upon a determination that the product has an effect on a surrogate endpoint or intermediate clinical endpoint that is reasonably likely to predict clinical benefit. The FDA considers a clinical benefit to be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as irreversible morbidity or mortality. For the purposes of Accelerated Approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit. The Accelerated Approval pathway may be used in cases in which the advantage of a new drug over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, Accelerated Approval is contingent on the sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drug’s clinical profile or risks and benefits for Accelerated Approval. If such post-approval studies fail to confirm the drug’s clinical profile or risks and benefits, the FDA may withdraw its approval of the drug.

If we choose to pursue Accelerated Approval, we intend to seek feedback from the FDA and will otherwise evaluate our ability to seek and receive such Accelerated Approval. There can be no assurance that the FDA will agree that our endpoint is an appropriate surrogate endpoint. There can also be no assurance that after our evaluation of the feedback and other factors we will decide to pursue or submit an NDA for Accelerated Approval or any other form of expedited development, review or approval. Similarly, there can be no assurance that after subsequent FDA feedback that we will continue to pursue or apply for Accelerated Approval or any other form of expedited development, review or approval, even if we initially decide to do so. Furthermore, if we decide to submit an application for Accelerated Approval, there can be no assurance that such submission or application will be accepted or that any expedited review or approval will be granted on a timely basis, or at all. The FDA or other non-U.S. authorities could also require us to conduct further studies prior to considering our application or granting approval of any type. Even if the FDA agreed that we could pursue an Accelerated Approval registration pathway, we might not be able to fulfill the FDA’s requirements with respect to chemistry, manufacturing and controls in a timely manner, which would cause delays, or approval might not be granted because our submission is deemed incomplete by the FDA.

A failure to obtain Accelerated Approval or any other form of expedited development, review or approval for our product candidates would result in a longer time period to commercialize such product candidate, could increase the cost of development of such product candidate and could harm our competitive position in the marketplace.

Serious adverse events of CRLX101 or any of our product candidates may be identified during clinical development. Further, other unexpected properties of our product candidates may be identified during manufacture or development. Such adverse events or unexpected properties could delay or prevent the continued development and/or marketing approval of any such product candidate.

Serious adverse events caused by, or other unexpected properties of, our product candidates could cause us, an institutional review board or regulatory authorities to interrupt, delay or halt clinical trials of one or more of our product candidates and could result in a more restrictive label or the delay or denial of marketing approval by the FDA or comparable non-U.S. regulatory authorities. If any of our product candidates is associated with serious adverse events or other unexpected properties, we may need to abandon development or limit development of that product candidate to certain uses or subpopulations in which those undesirable characteristics would be expected to be less prevalent, less severe or more tolerable from a risk-benefit perspective. If we learn that the manufacture of our product candidates generates unexpected impurities or product degradants, these properties could contribute to serious adverse events and negatively impact our overall development cost and timelines as we address those properties. Many compounds that initially showed promise in clinical or earlier stage testing have later been found to cause serious or unexpected adverse events and negatively affect overall development costs and timelines, which may even prevent further development of the compound.

Both camptothecin, the anti-cancer payload of CRLX101, and docetaxel, the anti-cancer payload of CRLX301, have been associated with toxicities. These toxicities led to discontinuation of the clinical development in the case of camptothecin and have led to dose adjustments, treatment discontinuation and extensive supportive care in the case of docetaxel. While we believe that our Dynamic Tumor Targeting Platform has the potential to improve the unfavorable adverse event profiles of both camptothecin and docetaxel, if this hypothesis is wrong and we experience unexpected or more severe toxicities in our ongoing clinical trials or in clinical trials we conduct in the future, whether due to the inclusion of camptothecin or docetaxel or another therapeutic as the anti-cancer payload in our NDCs or otherwise, we may not receive approval to market, or achieve commercial success with respect to, any of our product candidates, which could prevent us from ever generating revenues or achieving profitability. In addition, our Dynamic Tumor Targeting Platform may have other limitations with respect to targeting tumors and limiting exposure of normal tissue to our NDCs’ anti-cancer payload. For example, liver tissue has pore sizes that are generally larger than other normal tissue, and therefore, our NDCs and their anti-cancer payloads may preferentially concentrate in the liver.

We may not be successful in our efforts to identify or discover additional potential product candidates.

The development of new NDCs based on our Dynamic Tumor Targeting Platform is a key area of research for us. The drug discovery that we are conducting using our Dynamic Tumor Targeting Platform may not be successful in creating compounds that have commercial value or therapeutic utility. Our research programs may initially show promise in creating potential product candidates, yet fail to yield viable product candidates for clinical development for a number of reasons, including:

To identify new product candidates, our research programs will require substantial technical, financial and human resources. We may be unsuccessful in our efforts to identify new potential product candidates. In addition, we may focus our efforts and resources on one or more potential product candidates that ultimately prove to be unsuccessful. If we are unable to identify suitable additional compounds for preclinical and clinical development, our ability to develop product candidates and obtain product revenues in future periods could be compromised, which could result in significant harm to our financial position and adversely impact our stock price.

Even if one of our product candidates receives marketing approval, it may fail to achieve the degree of market acceptance by physicians, patients, third party payors and others in the medical community necessary for commercial success or the market opportunity for the product candidate may be smaller than we estimate.

We have never commercialized a product. Even if CRLX101 or any of our other product candidates is approved by the appropriate regulatory authorities for marketing and sale, it may nonetheless fail to gain sufficient market acceptance by physicians, patients, third party payors and others in the medical community. For example, physicians are often reluctant to switch their patients from existing therapies even when new and potentially more effective or convenient treatments enter the market. Further, patients often acclimate to the therapy that they are currently taking and do not want to switch unless their physicians recommend switching products or they are required to switch therapies due to lack of reimbursement for existing therapies.

Efforts to educate the medical community and third party payors on the benefits of our product candidates may require significant resources and may not be successful. If any of our product candidates is approved but does not achieve an adequate level of market acceptance, we may not generate significant revenues and may not become profitable. The degree of market acceptance of CRLX101 or any of our other product candidates, if approved for commercial sale, will depend on a number of factors, including:

The potential market opportunities for our product candidates are difficult to estimate precisely. Our estimates of the potential market opportunities are predicated on many assumptions, including industry knowledge and publications, third party research reports and other surveys. While we believe that our internal assumptions are reasonable, these assumptions involve the exercise of significant judgment on the part of our management, are inherently uncertain and the reasonableness of these assumptions has not been assessed by an independent source. If any of the assumptions proves to be inaccurate, the actual markets for our product candidates could be smaller than our estimates of the potential market opportunities.

If any of our product candidates receives marketing approval and we, or others, later discover that the drug is less effective than previously believed or causes undesirable side effects that were not previously identified, our ability to market the drug could be compromised.

Clinical trials of our product candidates are conducted in carefully defined subsets of patients who have agreed to enter into clinical trials. Consequently, it is possible that our clinical trials may indicate an apparent positive effect of a product candidate that is greater than the actual positive effect, if any, or, alternatively, fail to identify undesirable side effects. If, following approval of a product candidate, we, or others, discover that the drug is less effective than previously believed or causes undesirable side effects that were not previously identified, any of the following adverse events could occur:

Any of these events could have a material and adverse effect on our operations and business and could adversely impact our stock price.

If we are unable to establish sales, marketing and distribution capabilities or enter into acceptable sales, marketing and distribution arrangements with third parties, we may not be successful in commercializing any product candidates that we develop, if and when those product candidates are approved.

We do not have a sales, marketing or distribution infrastructure and have limited experience in the sale, marketing or distribution of pharmaceutical products. To achieve commercial success for any approved product, we must either develop a sales and marketing organization or outsource these functions to third parties. If approved, we expect to commercialize our lead product candidates in the United States directly with a small and highly focused commercialization organization. The development of sales, marketing and distribution capabilities will require substantial resources, will be time-consuming and could delay any product launch. We expect that we will commence the development of these capabilities prior to receiving approval of any of our product candidates. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing and distribution capabilities is delayed or does not occur for any reason, we could have prematurely or unnecessarily incurred these commercialization costs. Such a delay may be costly, and our investment could be lost if we cannot retain or reposition our sales and marketing personnel. In addition, we may not be able to hire or retain a sales force in the United States that is sufficient in size or has adequate expertise in the medical markets that we plan to target. If we are unable to establish or retain a sales force and marketing and distribution capabilities, our operating results may be adversely affected. If a potential partner has development or commercialization expertise that we believe is particularly relevant to one of our products, then we may seek to collaborate with that potential partner even if we believe we could otherwise develop and commercialize the product independently.

We expect to seek one or more strategic partners for commercialization of our product candidates outside the United States. As a result of entering into arrangements with third parties to perform sales, marketing and distribution services, our product revenues or the profitability of these product revenues may be lower, perhaps substantially lower, than if we were to directly market and sell products in those markets. Furthermore, we may be unsuccessful in entering into the necessary arrangements with third parties or may be unable to do so on terms that are favorable to us. In addition, we may have little or no control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our products effectively.

If we do not establish sales and marketing capabilities, either on our own or in collaboration with third parties, we will not be successful in commercializing any of our product candidates that receive marketing approval.

We face substantial competition from other pharmaceutical and biotechnology companies and our operating results may suffer if we fail to compete effectively.

The development and commercialization of new drug products is highly competitive. We expect that we will face significant competition from major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide with respect to CRLX101, CRLX301 and any future product candidates that we may seek to develop or commercialize. Specifically, due to the large unmet medical need, global demographics and relatively attractive reimbursement dynamics, the oncology market is fiercely competitive and there are a number of large pharmaceutical and biotechnology companies that currently market and sell products or are pursuing the development of product candidates for the treatment of cancer. Our competitors may succeed in developing, acquiring or licensing technologies and drug products that are more effective, have fewer or more tolerable adverse events or are less costly than any product candidates that we are currently developing or that we may develop, which could render our product candidates obsolete and noncompetitive.

Companies with marketed nanotechnology-based oncology products include Celgene Corporation (Abraxane® (nab-paclitaxel) indicated for breast cancer, NSCLC and pancreatic cancer), Janssen Products, LP (Doxil indicated for ovarian cancer and, in combination with Velcade^® (bortezomib), for multiple myeloma), Merrimack Pharmaceuticals, Inc. (Onivyde™ (irinotecan liposomal injection) indicated for pancreatic and colorectal cancer), Spectrum Pharmaceuticals, Inc. (Marqibo ® (vincristine sulfate liposome injection) indicated for relapsed Philadelphia chromosome-negative acute lymphoblastic leukemia) and. Companies with nanotechnology-based oncology product candidates in clinical development include, without limitation, BIND Therapeutics, Inc. (BIND 014 for squamous NSCLC, urothelial carcinoma, cholangiocarcinoma, cervical cancer and squamous cell carcinoma of the head and neck), Celator Pharmaceuticals, Inc. (CPX-351 for acute myeloid leukemia), Celsion Corporation (ThermoDox® (lyso-thermosensitive liposomal doxorubicin) for liver cancer and breast cancer), Cytimmune Sciences, Inc. (CYT-6091 for NSCLC), Cristal Delivery B.V. d/b/a Cristal Therapeutics (CriPec® docetaxel for oncology), Nektar Therapeutics (NKTR102 for solid tumors), Nippon Kayku Seizo Co., Ltd. (NK105 in breast cancer), Starpharma Holdings Ltd. (DEP® docetaxel for oncology), and Supratek Pharma Inc. (SP1049C for solid tumors).

Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain FDA or other marketing approval for their product candidates before we are able to obtain approval for our product candidates, which could result in our competitors establishing a strong market position before we are able to enter the market. The competition for CRLX101 in our targeted indications includes the following:

Renal Cell Carcinoma. In relapsed RCC, the FDA-approved therapies commonly used for treatment represent several mechanistic classes — immune checkpoint inhibitors of PD-1, tyrosine kinase inhibitors, or TKIs, including small molecules and antibody to VEGF ligand, Avastin, and inhibitors of mTOR — and there are no approved cytotoxic drugs that we are aware of. For example, Bristol-Myers Squibb Company’s PD-1 antibody Opdivo^® (nivolumab) is approved in relapsed RCC following progression on one targeted therapy. There are also several drugs in development that have the potential to obtain FDA marketing approval and change the standard of care. If this occurs, currently available treatments could be displaced and our commercial opportunity could be reduced. Antibodies against PD-1/PD-L1 and CTL-A4 are in late stage development in first line RCC, both as monotherapies and in combination with other agents including Avastin and small molecule TKIs. Bristol-Myers Squibb is also developing Opdivo in combination with Yervoy™ (ipilimumab) in first line, Merck is developing Keytruda^® (pembrolizumab) in combination with Votrient^® (pazopanib) in first line and Roche is developing a PD-L1 inhibitor, atezolizumab, in combination with Avastin in first line. Argos Therapeutics, Inc. is developing AGS-003, a dendritic cell therapy, in first line RCC for patients with unfavorable risk. New small molecule TKIs are also in development. Exelixis Inc.’s TKI, Cometriq^® (cabozantinib), TRACON Pharmaceuticals, Inc.’s TRC105, and Acceleron Pharma, Inc.’s dalantercept (the latter two are in combination with Inlyta^® (axitinib)) are in development in second line or later stage relapsed RCC. Eisai Co., Ltd. is developing Lenvima® (lenvantinib) in combination with Afinitor® (everolimus) in second line. AVEO Pharmaceuticals, Inc. is developing tivozanib in third line.

Although most of these product candidates are being tested for earlier lines of therapy, they also have the potential to change the standard of care in later lines of therapy in advanced RCC, and to impact the regulatory thresholds for product approvals in this setting. These factors could create questions about the optimal sequence of agents and, among other things, could change the role of Avastin in the treatment of RCC or result in existing first-line therapies being prescribed instead of later lines of therapy. Determining the optimal sequence of agents could be further complicated if their approval and/or availability is different in the United States and Europe. If this occurs, it would potentially reduce the commercial opportunity for CRLX101 in relapsed RCC.

Relapsed Ovarian Cancer. In relapsed ovarian cancer, the recent FDA approvals of Avastin with chemotherapy and Lynparza in BRCA mutated patients has changed the standard of care, which could reduce the commercial opportunity for CRLX101 in this indication. In addition, multiple companies are developing other therapeutic candidates, which are at various stages of development. For example, Abbvie Inc., Clovis Oncology, Inc. Medivation Inc., and TESARO Inc. all have PARP inhibitors in development in BRCA mutated ovarian cancer and breast cancer. ImmunoGen is also developing IMGN853 in folate receptor positive ovarian cancer. OncoMed Pharmaceuticals is developing demcizumab, and Genentech, Inc. is developing DMOT4039A. Although each of these agents has the potential to be used in combination with CRLX101, thereby expanding the market for CRLX101, they also have the potential to compete with CRLX101.

Many of our existing and potential future competitors have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining marketing approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

If the FDA or comparable non-U.S. regulatory authorities approve generic versions of any of our products that receive marketing approval, or such authorities do not grant our products appropriate periods of data exclusivity before approving generic versions of our products, the sales of our products could be adversely affected.

Once an NDA is approved, the product covered thereby becomes a “reference listed drug” in the FDA’s publication, “Approved Drug Products with Therapeutic Equivalence Evaluations.” Manufacturers may seek approval of generic versions of reference listed drugs through submission of abbreviated new drug applications, or ANDAs, in the United States. In support of an ANDA, a generic manufacturer need not conduct clinical studies. Rather, the applicant generally must show that its product has the same active ingredient(s), dosage form, strength, route of administration and conditions of use or labeling as the reference listed drug and that the generic version is bioequivalent to the reference listed drug, meaning it is absorbed in the body at the same rate and to the same extent. Generic products may be significantly less costly to bring to market than the reference listed drug and companies that produce generic products are generally able to offer them at lower prices. Thus, following the introduction of a generic drug, a significant percentage of the sales of any branded product or reference listed drug may be typically lost to the generic product.

The FDA may not approve an ANDA for a generic product until any applicable period of non-patent exclusivity for the reference listed drug has expired. The FDCA provides a period of five years of non-patent exclusivity for a new drug containing a new chemical entity. Specifically, in cases in which such exclusivity has been granted, an ANDA may not be filed with the FDA until the expiration of five years unless the submission is accompanied by a Paragraph IV certification that a patent covering the reference listed drug is either invalid or will not be infringed by the generic product, in which case the applicant may submit its application four years following approval of the reference listed drug. While we believe that CRLX101 would be treated as a new chemical entity by the FDA and, therefore, if approved, should be afforded five years of data exclusivity, the FDA may disagree with that conclusion and may approve generic products after a period that is less than five years. Our other product candidates, including CRLX301, may be treated as new chemical entities as well, but at this point we cannot predict the probability of success in that regard. Manufacturers may seek to launch these generic products following the expiration of the applicable marketing exclusivity period, even if we still have patent protection for our product.

Competition that our products may face from generic versions of our products could materially and adversely impact our future revenue, profitability and cash flows and substantially limit our ability to obtain a return on the investments we have made in those product candidates.

CRLX301 is, and any additional product candidate that we may develop in the future may be, an NDC that includes a generically available therapeutic as its anti-cancer payload. If physicians and/or third party payors do not believe our product offers substantial advantages over other therapies incorporating the same generic anti-cancer payload, we may not be able to successfully commercialize our product.

Although we have intellectual property rights, including composition of matter patents, covering our product candidates, if approved, we expect that our product candidates will compete in the same indications against other nanoparticles and delivery platforms incorporating the same generic therapeutics. In particular, if any of our product candidates is approved and becomes commercially successful, other companies may intensify their efforts to develop a competing product that includes the corresponding generic therapeutic. If physicians, rightly or wrongly, do not believe that a product that we develop offers substantial advantages over another nanoparticle or delivery platform incorporating the same generic therapeutic, physicians might not prescribe our product. In addition, third party payors might refuse to provide reimbursement for a product that we develop when another nanoparticle or delivery platform incorporating the same generic therapeutic offers a cheaper alternative therapy in the same indication, or might otherwise encourage use of another nanoparticle or delivery platform incorporating the same generic therapeutic over our product, even if our product possesses favorable pharmaceutical properties.

Even if we are able to commercialize any product candidate that we develop, the product may become subject to unfavorable pricing regulations, third party payor reimbursement practices or healthcare reform initiatives that could harm our business.

The commercial success of our product candidates will depend substantially, both domestically and abroad, on the extent to which the costs of our product candidates will be paid by health maintenance, managed care, pharmacy benefit and similar healthcare management organizations, or reimbursed by government health administration authorities, private health coverage insurers and other third party payors. If reimbursement is not available, or is available only at limited levels, we may not be able to successfully commercialize our product candidates. Even if coverage is provided, the approved reimbursement amount may not be high enough to allow us to establish and maintain pricing sufficient to realize a meaningful return on our investment.

There is significant uncertainty related to third party payor coverage and reimbursement of newly approved drugs. Marketing approvals, pricing and reimbursement for new drug products vary widely from country to country. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some non-U.S. markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain marketing approval for a product in a particular country, but then be subject to price regulations that delay commercial launch of the product, possibly for lengthy periods, which may negatively impact the revenues we are able to generate from the sale of the product in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more product candidates, even if our product candidates obtain marketing approval.

Our ability to commercialize CRLX101 or any other product candidate will depend in part on the extent to which coverage and reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and third party payors, such as private health insurers and health maintenance organizations, decide which medications they will cover and establish reimbursement levels. The healthcare industry is acutely focused on cost containment, both in the United States and elsewhere. Government authorities and third party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications, which could affect our ability to sell our product candidates profitably. These payors may not view our products, if any, as cost-effective, and coverage and reimbursement may not be available to our customers, or may not be sufficient to allow our products, if any, to be marketed on a competitive basis. Cost-control initiatives could cause us to decrease the price we might establish for products, which could result in lower than anticipated product revenues. If the prices for our products, if any, decrease or if governmental and other third party payors do not provide adequate coverage or reimbursement, our prospects for revenue and profitability will suffer.

There may also be delays in obtaining coverage and reimbursement for newly approved drugs, and coverage may be more limited than the indications for which the drug is approved by the FDA or comparable non-U.S. regulatory authorities. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Reimbursement rates may vary, by way of example, according to the use of the drug and the clinical setting in which it is used. Reimbursement rates may also be based on reimbursement levels already set for lower cost drugs or may be incorporated into existing payments for other services.

In addition, increasingly, third party payors are requiring higher levels of evidence of the benefits and clinical outcomes of new technologies and are challenging the prices charged. We cannot be sure that coverage will be available for any product candidate that we, or others, commercialize and, if available, that the reimbursement rates will be adequate. Further, the net reimbursement for drug products may be subject to additional reductions if there are changes to laws that presently restrict imports of drugs from countries

where they may be sold at lower prices than in the United States. An inability to promptly obtain coverage and adequate payment rates from both government-funded and private payors for any our product candidates for which we obtain marketing approval could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize products and our financial condition.

Product liability lawsuits against us could divert our resources, cause us to incur substantial liabilities and limit commercialization of any products that we may develop.

We face an inherent risk of product liability claims as a result of the clinical testing of our product candidates despite obtaining informed consents from our clinical trial participants. We will face an even greater risk if we commercially sell any product that we may develop. For example, we may be sued if any product we develop allegedly causes injury or is found to be otherwise unsuitable during clinical testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our product candidates. Regardless of the merits or eventual outcome, liability claims may result in:

We maintain general liability, product liability and umbrella liability insurance. Our existing insurance coverage may not fully cover potential liabilities that we may incur. The cost of any product liability litigation or other proceeding, even if resolved in our favor, could be substantial. We will need to increase our insurance coverage as our risks of exposure increase, which, for example, would happen if and when we begin selling any product candidate that receives marketing approval. In addition, certain types of insurance coverage are becoming increasingly expensive. If we are unable to obtain or maintain sufficient insurance coverage at an acceptable cost or to otherwise protect against potential product liability claims, it could prevent or inhibit the development and commercial production and sale of our product candidates, which could adversely affect our business, financial condition, results of operations and prospects.

We rely on third parties to conduct ISTs of some of our product candidates. Any failure by a third party to meet its obligations with respect to the clinical development of our drug candidates may delay or impair our ability to obtain regulatory approval for our product candidates.

We rely on academic institutions to conduct and sponsor some of our clinical trials relating to some of our product candidates. We do not control the design or administration of ISTs, and our reliance on third parties to conduct ISTs could, depending on the actions of such third parties, jeopardize the quality or timeliness of the clinical data generated and adversely affect our ability to obtain marketing approval from the FDA or other applicable regulatory authorities.

Such arrangements provide us with certain information rights with respect to ISTs, including access to and the ability to use and reference the data resulting from the IST, including for our own regulatory filings. However, we do not control patient enrollment in, or the quality, timing and reporting of the data from, ISTs, nor do we own the data from the ISTs. Moreover, if we are unable to confirm or replicate the results from the ISTs or if negative results are obtained in the ISTs, we would likely be further delayed or prevented from advancing further clinical development of our drug candidates. Further, if investigators or institutions breach their obligations with respect to the clinical development of our drug candidates, or if the data proves to be unfavorable, incomplete or inconclusive, then our ability to design and conduct any future clinical trials ourselves may be adversely affected.

The FDA or non-U.S. regulatory authorities may disagree with the sufficiency of our right of reference to the preclinical, manufacturing or clinical data generated by ISTs, or our interpretation of preclinical, manufacturing or clinical data from ISTs. If so, the FDA or other non-U.S. regulatory authorities may require us to obtain and submit additional preclinical, manufacturing, or clinical data before we may initiate our planned trials and/or may not accept such additional data as adequate to initiate our planned trials. Moreover, there is typically no independent review of the results of ISTs. Therefore, the investigators may interpret the results of ISTs more favorably than an independent review would.

Moreover, ISTs of our product candidates may continue even after we commence company-sponsored trials in the same or different indications. To the extent the results of these ISTs are inconsistent with, or different from, the results of our company-sponsored trials, the FDA or a non-U.S. regulatory authority may question the results of the company-sponsored trial, or subject such results to greater scrutiny than it otherwise would. In these circumstances, the FDA or such other non-U.S. regulatory authorities may require us to obtain and submit additional clinical data, which could delay clinical development or marketing approval of the applicable product candidate.

We rely, and expect to continue to rely, on third parties to conduct our clinical trials, and those third parties may not perform satisfactorily, including failing to meet deadlines for the completion of such trials.

We currently rely on third party clinical research organizations, or CROs, to conduct our clinical trials. We also rely on third parties including CROs to collect and monitor adverse event data for our clinical trials. We expect to continue to rely on third parties, such as CROs, clinical data management organizations, medical institutions and clinical investigators, to conduct our clinical trials. Our agreements with these third parties generally allow the third party to terminate the agreement at any time. If we are required to enter into alternative arrangements because of any such termination the introduction of our product candidates to market could be delayed.

Our reliance on these third parties for research and development activities will reduce our control over these activities but will not relieve us of our responsibilities. For example, we design our clinical trials and will remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with standards, commonly referred to as good clinical practices for conducting, recording and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. Our reliance on third parties that we do not control does not relieve us of these responsibilities and requirements. We are also required to register ongoing clinical trials and post the results of completed clinical trials on a government-sponsored database, ClinicalTrials.gov, within specified timeframes. Failure to do so can result in fines, adverse publicity and civil and criminal sanctions.

Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our clinical trials in accordance with regulatory requirements or our stated protocols, we will not be able to obtain, or may be delayed in obtaining, marketing approvals for our product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our product candidates.

We also expect to rely on other third parties to manufacture, store and distribute drug supplies for our clinical trials. Any performance failure on the part of our distributors could delay clinical development or marketing approval of our product candidates or commercialization of our products, producing additional losses and depriving us of potential product revenue.

We have entered into collaborations, and may seek to enter into additional collaborations, with third parties for the development and commercialization of our product candidates. If such collaborations are not successful, or we fail to enter into additional collaborations, we may not be able to capitalize on the market potential of our product candidates.

On November 17, 2015 we announced a collaboration with AstraZeneca AB, or AstraZeneca, and the National Cancer Institute, or the NCI, part of the National Institutes of Health, to conduct a Phase 1/2a clinical trial of the combination of Lynparza and CRLX101 in patients with small cell lung cancer. We may seek additional third-party collaborators for development and commercialization of our product candidates. Our likely collaborators for any marketing, distribution, development, licensing or broader collaboration arrangements include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies, biotechnology companies and certain governmental agencies. We will have limited control over the amount and timing of resources that any of our current or potential future collaborations dedicate to the development or commercialization of our product candidates. Our ability to generate revenues from these arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements.

Collaboration agreements may not lead to development or commercialization of product candidates in the most efficient manner or at all. If a collaborator of ours were to be involved in a business combination or divestiture, the continued pursuit and emphasis on our product development or commercialization program could be delayed, diminished or terminated.

If we are not able to establish additional collaborations, we may have to alter our development and commercialization plans.

Our drug development programs and the potential commercialization of our product candidates will require substantial additional cash to fund expenses. While we have entered into a collaboration with AstraZeneca and the NCI to conduct a Phase 1/2a clinical trial of the combination of Lynparza and CRLX101 in patients with small cell lung cancer, we plan to seek further collaborations with pharmaceutical and biotechnology companies or institutions for the development and potential commercialization of CRLX101 or other product candidates.

We face significant competition in seeking appropriate collaborators. Whether we reach a definitive agreement with a potential collaborator will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of clinical trials, the likelihood of approval by the FDA or similar regulatory authorities outside the United States, the potential market for the subject product candidate, the costs and complexities of manufacturing and delivering such product candidate to patients, the potential of competing products, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge and industry and market conditions generally. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our product candidate. We may also be restricted under future license agreements from entering into agreements on certain terms with potential collaborators. Collaborations are complex and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators.

We may not be able to negotiate additional collaborations on a timely basis, on acceptable terms, or at all. If we are unable to do so, we may have to curtail the development of a product candidate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of any sales or marketing activities, or increase

our expenditures and undertake development or commercialization activities at our own expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we may not be able to further develop our product candidates or bring them to market and generate product revenue.

We contract with third parties for the manufacture of our product candidates for preclinical and clinical testing and expect to continue to do so for commercialization. This reliance on third parties increases the risk that we will not have sufficient quantities of our product candidates or such quantities at an acceptable cost, which could delay, prevent or impair our development or commercialization efforts.

We do not currently own or operate manufacturing facilities for the production of clinical quantities of CRLX101 or CRLX301 and have limited personnel with manufacturing experience. We currently rely on and expect to continue to rely on third party contract manufacturers to manufacture supplies of our product candidates for preclinical and clinical testing, as well as for commercial manufacture if any of our product candidates receive marketing approval.

CRLX101 and CRLX301 must be manufactured through complex, multi-step synthesis processes that are time-consuming and involve special conditions at certain stages. Drug substance manufacture requires high potency containment, and drug product manufacture requires high potency containment under aseptic conditions, also referred to as sterile manufacture. Failures in either drug substance manufacture or drug product manufacture, whether on the part of our existing or future manufacturers or as a result of our failure to make timely and effective improvements in our manufacturing processes, could materially delay clinical development or marketing approval of our product candidates or result in our inability to generate sufficient supplies to meet clinical or commercial demands. For example, in 2015 we experienced a CRLX101 drug substance manufacturing failure due to an out-of-specification event, and the process of obtaining a new batch will require several months to complete.

Although we currently have backup suppliers for several stages of the manufacturing process, we rely on one supplier for each stage of this process. If our current contract manufacturers cannot perform as agreed, or become unavailable to us for any reason, we may be required to replace such manufacturers. Our agreements with our third party manufacturers can be terminated by us or such manufacturers on short notice. If any of our existing manufacturers should become unavailable to us for any reason or should be unable to secure additional manufacturing capacity in the event of higher than anticipated product demand, we may incur additional cost or delay in identifying or qualifying replacements. In addition, while we believe that our existing supplier of drug substance or an alternative supplier would be capable of continuing to produce drug substance in commercial quantities, we will need to identify a third-party manufacturer capable of providing commercial quantities of drug product. If we are unable to arrange for such a third-party manufacturing source, or fail to do so on commercially reasonable terms, we may not be able to successfully produce and market CRLX101 or any other product candidate or may be delayed in doing so.

Even if we are able to establish such arrangements with third party manufacturers, reliance on third party manufacturers entails additional risks, including:

Third party manufacturers may not be able to comply with current good manufacturing practices, or cGMP, regulations or similar regulatory requirements outside the United States. If our contract manufacturers cannot successfully manufacture material that conforms to our specifications and the strict regulatory requirements of the FDA or applicable foreign regulatory agencies, our ability to secure and/or maintain regulatory approval for our product candidates could be adversely affected. Our failure, or the failure of our third party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including clinical holds, fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates or products, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect supplies of our products.

CRLX101, CRLX301 and any future product candidates that we may develop may compete with other product candidates and products for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP regulations and that might be capable of manufacturing for us.

In addition, we typically rely on our manufacturers to purchase from third-party suppliers the materials necessary to produce our product candidates for our clinical studies. There are a small number of suppliers for certain capital equipment and raw materials that are used in the manufacture of our drugs. Such suppliers may not sell these raw materials to our manufacturers at the times we need them or on commercially reasonable terms. We do not have any control over the process or timing of the acquisition of these raw materials by our manufacturers. Moreover, we currently do not have any agreements for the commercial production of these raw materials. Any significant delay in the supply of a product candidate or the raw material components thereof for an ongoing clinical trial due to the need to replace a third-party manufacturer could considerably delay completion of our clinical studies, product testing and potential regulatory approval of our product candidates. If our manufacturers or we are unable to purchase these raw materials after regulatory approval has been obtained for our product candidates, the commercial launch of our product candidates would be delayed or there would be a shortage in supply, which would impair our ability to generate revenues from the sale of our product candidates.

Our current and anticipated future dependence upon others for the manufacture of our product candidates may adversely affect our future profit margins and our ability to commercialize any products that receive marketing approval on a timely and competitive basis.

If we are unable to obtain and maintain patent protection for our technology and products or if the scope of the patent protection obtained is not sufficiently broad, our competitors could develop and commercialize technology and products similar or identical to ours, and our ability to successfully commercialize our technology and products may be impaired.

Our success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries with respect to our proprietary technology and products. We seek to protect our proprietary position by filing patent applications in the United States and abroad related to our novel technologies and product candidates.

The patent prosecution process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection. Moreover, in some circumstances, we do not have the right to control the preparation, filing and prosecution of patent applications, or to maintain the patents, covering technology that we license from third parties. Therefore, these patents and applications may not be prosecuted and enforced in a manner consistent with the best interests of our business.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation. In addition, the laws of non-U.S. countries may not protect our rights to the same extent as the laws of the United States. For example, European patent law restricts the patentability of methods of treatment of the human body more than United States law does. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, and in some cases not at all. Therefore, we cannot know with certainty whether we were the first to make the inventions claimed in our owned or licensed patents or pending patent applications, or that we or our licensors were the first to file for patent protection of such inventions. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highly uncertain. Our pending and future patent applications may not issue as patents that protect our technology or products, in whole or in part, or which effectively prevent others from commercializing competitive technologies and products. Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection.

Recent patent reform legislation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our owned or licensed issued patents. On September 16, 2011, the Leahy-Smith America Invents Act, or the Leahy-Smith Act, was signed into law. The Leahy-Smith Act includes a number of significant changes to United States patent law. The Leahy-Smith Act includes provisions that affect the way patent applications are prosecuted and affect patent litigation. The United States Patent and Trademark Office, or USPTO, recently developed new regulations and procedures to govern administration of the Leahy-Smith Act. However, many of the substantive changes to patent law associated with the Leahy-Smith Act, and in particular, the first to file provisions, only became effective on March 16, 2013. Accordingly, it is not clear what, if any, impact the Leahy-Smith Act will have on the operation of our business. However, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our owned or licensed patent applications and the enforcement or defense of our owned or licensed issued patents, all of which could have a material adverse effect on our business and financial condition.

Moreover, we may be subject to third party preissuance submissions of prior art to the USPTO, or become involved in opposition, derivation, reexamination, inter partes review, post-grant review or interference proceedings challenging our owned or licensed patent rights or the patent rights of others. An adverse determination in any such submission, proceeding or litigation could reduce the scope of, or invalidate, our patent rights, allow third parties to commercialize our technology or products and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize products without infringing third party patent rights. In addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

Even if our owned and licensed patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from competing with us, or otherwise provide us with any competitive advantage. Our competitors may be able to circumvent our owned or licensed patents by developing similar or alternative technologies or products in a non-infringing manner.

The issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our owned and licensed patents may be challenged in courts or patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or freedom to operate, or in patent claims being narrowed, invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection of our technology and products. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

We may become involved in lawsuits to protect or enforce our patents or other intellectual property, which could be expensive, time consuming and unsuccessful.

Competitors may infringe our owned or licensed patents or other intellectual property. To counter infringement or unauthorized use, we may be required to file or participate in infringement claims, which can be expensive and time consuming. Any claims we or our licensors assert against perceived infringers could provoke these parties to assert counterclaims against us alleging that we infringe their patents. In addition, in a patent infringement proceeding, a court may decide that a patent of ours or our licensor is invalid or unenforceable, in whole or in part, construe the patent’s claims narrowly or refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation proceeding could put one or more of our owned or licensed patents at risk of being invalidated or interpreted narrowly.

CRLX101, CRLX301 and certain aspects of our platform technology are protected by patents assigned by or exclusively licensed from other companies or institutions. If these third parties terminate their agreements with us or fail to maintain or enforce the underlying patents, or we otherwise lose our rights to these patents, our competitive position and our market share in the markets for any of our approved products will be harmed.

We are a party to several license agreements and certain aspects of our business depend on patents and/or patent applications owned by others. In particular, we hold exclusive licenses from Calando Pharmaceuticals, Inc., or Calando, and California Institute of Technology, or Caltech, and have been assigned certain patents from Calando for CRLX101, CRLX301 and CDP-based product candidates. We also hold an exclusive license from the State University of New York, or SUNY, related to taxane-containing NDCs, such as CRLX301. We are likely to enter into additional license agreements as part of the development of our business in the future. If we are unable to maintain these patent rights for any reason, our ability to develop and commercialize our product candidates could be materially harmed.

Our licensors may not successfully prosecute certain patent applications under which we are licensed and on which our business depends. Even if patents issue from these applications, our licensors may fail to maintain these patents, may decide not to pursue litigation against third party infringers, may fail to prove infringement, or may fail to defend against counterclaims of patent invalidity or unenforceability.

Risks with respect to parties from whom we have obtained intellectual property rights may also arise out of circumstances beyond our control. For example, in March 2014, Calando entered Chapter 7 bankruptcy and, as a result, the intellectual property rights we have obtained from Calando are subject to potential risks that may arise in connection with bankruptcy. For instance, while our ability to develop and/or commercialize our current product candidates and our ability to utilize our platform are not dependent on the rights that we license from Calando, our license agreements with Calando could be rejected in connection with Calando’s bankruptcy, in which case, we could, subject to elections and other rights and defenses that may be available to us, lose certain rights granted to us under such licenses. In March 2015, the bankruptcy court granted Calando’s bankruptcy trustee’s application to retain a broker to help sell Calando’s rights in certain assets including its rights in the license agreements with Cerulean. We reserved our rights with respect to any such sale.

In addition, in spite of our best efforts, our licensors might conclude that we have materially breached our intellectual property agreements and might therefore terminate the intellectual property agreements, thereby removing our ability to obtain regulatory approval and to market products covered by these intellectual property agreements. If our intellectual property agreements are terminated, or if the underlying patents fail to provide the intended market exclusivity, competitors may have the freedom to seek regulatory approval of, and to market, products similar or identical to ours. Moreover, if our intellectual property agreements are terminated, our former licensors and/or assignors may be able to prevent us from utilizing the technology covered by the licensed or assigned patents and patent applications. For example, under our agreements with Calando, which relate to CRLX101 and our platform, if we fail to meet our payment obligations and do not adequately cure such failure, or if we terminate one or both of these agreements, other than for specified safety concerns, we are required to grant Calando an exclusive (even as to Cerulean), royalty-free license under the patent rights assigned pursuant to such terminated agreement and to assign the related IND to Calando. Moreover, if we fail to meet our diligence obligations under one or both of our agreements with Calando, Calando may convert the license to a non-exclusive license, and we will be required to grant Calando a non-exclusive license under the patent rights assigned to us pursuant to such terminated agreement. This could have a material adverse effect on our competitive business position and our business prospects.

If we fail to comply with our obligations in our intellectual property agreements with third parties, we could lose rights that are important to our business.

We are party to multiple intellectual property agreements that impose, and we may enter into additional intellectual property agreements that may impose, various diligence, milestone payment, royalty and other obligations on us. Under our existing intellectual property agreements, we are obligated to pay royalties on the net sales of product candidates or related technologies to the extent they are covered by the agreement. We also have diligence and development obligations under those agreements. If we fail to comply with our obligations under current or future intellectual property agreements, our counterparties may have the right to terminate these agreements, in which event we might not be able to develop, manufacture or market any product that is covered by the agreement or face other penalties under the agreement. Such an occurrence could materially adversely affect the value of the product candidate being developed under any such agreement. Termination of these agreements or reduction or elimination of our rights under these agreements may result in our having to negotiate new or reinstated agreements with less favorable terms, or cause us to lose our rights under these agreements, including our rights to important intellectual property or technology.

Some intellectual property which we have licensed may have been discovered through government funded programs and thus may be subject to federal regulations such as “march-in” rights, certain reporting requirements, and a preference for United States industry. Compliance with such regulations may limit our exclusive rights, subject us to expenditure of resources with respect to reporting requirements, and limit our ability to contract with non-U.S. manufacturers.

Some of the intellectual property rights we have licensed may have been generated through the use of United States government funding and may therefore be subject to certain federal regulations. For example, some of the intellectual property rights licensed to us under the SUNY agreement and which are relevant to taxane containing NDCs such as CRLX301 may have been generated using United States government funds. As a result, the United States government may have certain rights to intellectual property embodied in CRLX301 pursuant to the Bayh-Dole Act of 1980. These United States government rights in certain inventions developed under a government-funded program include a non-exclusive, non-transferable, irrevocable worldwide license to use inventions for any governmental purpose. In addition, the United States government has the right to require us to grant exclusive, partially exclusive, or non-exclusive licenses to any of these inventions to a third party if it determines that: (i) adequate steps have not been taken to commercialize the invention; (ii) government action is necessary to meet public health or safety needs; or (iii) government action is necessary to meet requirements for public use under federal regulations (also referred to as “march-in rights”). The United States government also has the right to take title to these inventions if we fail to disclose the invention to the government and fail to file an application to register the intellectual property within specified time limits. In addition, the United States government may acquire title to these inventions in any country in which a patent application is not filed within specified time limits. Intellectual property generated under a government funded program is also subject to certain reporting requirements, compliance with which may require us to expend substantial resources. In addition, the United States government requires that any products embodying the subject invention or produced through the use of the subject invention be manufactured substantially in the United States. The manufacturing preference requirement can be waived if the owner of the intellectual property can show that reasonable but unsuccessful efforts have been made to grant licenses on similar terms to potential licensees that would be likely to manufacture substantially in the United States or that under the circumstances domestic manufacture is not commercially feasible. This preference for United States manufacturers may limit our ability to contract with non-U.S. product manufacturers for products covered by such intellectual property.

We currently do not plan to apply for additional United States government funding, but if we do, and we discover compounds or drug candidates as a result of such funding, intellectual property rights to such discoveries may be subject to the applicable provisions of the Bayh-Dole Act.

Third parties may initiate legal proceedings alleging that we are infringing their intellectual property rights, the outcome of which would be uncertain and could have a material adverse effect on the success of our business.

Our commercial success depends upon our ability to develop, manufacture, market and sell our product candidates and use our proprietary technologies without infringing the proprietary rights of third parties. There is considerable intellectual property litigation in the biotechnology and pharmaceutical industries. We may become party to, or be threatened with, future adversarial proceedings or litigation regarding intellectual property rights with respect to our products and technology, including interference or derivation proceedings before the USPTO. Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future.

If we are found to infringe a third party’s intellectual property rights, we could be required to obtain a license from such third party to continue developing and marketing our products and technology. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. We could be forced, including by court order, to cease commercializing the infringing technology or product. In addition, we could be found liable for monetary damages, including treble damages and attorneys’ fees if we are found to have willfully infringed a patent. A finding of infringement could prevent us from commercializing our product candidates or force us to cease some of our business operations, which could materially harm our business. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar negative impact on our business.

We may be subject to claims by third parties asserting that we or our employees have misappropriated their intellectual property, or claiming ownership of what we regard as our own intellectual property.

Many of our employees were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our employees do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these employees have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such employee’s former employer. Litigation may be necessary to defend against these claims.

In addition, while it is our policy to require our employees and contractors who may be involved in the development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in timely obtaining such an agreement with each party who in fact develops intellectual property that we regard as our own. Even if timely obtained, such agreements may be breached, and we may be forced to bring claims against third parties, or defend claims they may bring against us, to determine the ownership of what we regard as our intellectual property.

If we fail in prosecuting or defending any such claims, we may lose valuable intellectual property rights or personnel, in addition to paying monetary damages. Even if we are successful in prosecuting or defending against such claims, litigation could result in substantial costs and be a distraction to management.

Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses, and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments, and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to conduct such litigation or proceedings adequately. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could compromise our ability to compete in the marketplace.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patents for some of our technology and product candidates, we also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. We seek to protect these trade secrets, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to them, such as our employees, corporate collaborators, outside scientific collaborators, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and

we may not be able to obtain adequate remedies for such breaches. In addition, we face the risk of cybercrime. For instance, someone could hack our information networks and gain illicit access to our proprietary information including our trade secrets. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. Even if we are successful in prosecuting such claims, any remedy awarded may be insufficient to fully compensate us for the improper disclosure or misappropriation. In addition, some courts inside and outside the United States are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them, or those to whom they communicate it, from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed.

Risks Related to Regulatory Approval and Marketing of Our Product Candidates and Other Legal Compliance Matters

Even if we complete the necessary clinical trials, the marketing approval process is expensive, time consuming and uncertain and may prevent us from obtaining approvals for the commercialization of some or all of our product candidates. If we are not able to obtain, or if there are delays in obtaining, required regulatory approvals, we will not be able to commercialize our product candidates, and our ability to generate revenue will be materially impaired.

Our product candidates and the activities associated with their development and commercialization, including their design, testing, manufacture, safety, efficacy, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, are subject to comprehensive regulation by the FDA and other regulatory agencies in the United States and by the EMA and similar regulatory authorities outside the United States. Failure to obtain marketing approval for a product candidate will prevent us from commercializing the product candidate. Our product candidates are in the early stages of development and are subject to the risks of failure inherent in drug development. We have not received approval to market any of our product candidates from regulatory authorities in any jurisdiction. We have only limited experience in conducting and managing the clinical trials, and in filing and supporting the applications necessary to gain marketing approvals and expect to rely on third party CROs to assist us in this process. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. Our product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit commercial use. New cancer drugs frequently are indicated only for patient populations that have not responded to an existing therapy or have relapsed. If any of our product candidates receives marketing approval, the accompanying label may limit the approved use of our drug in this way, which could limit sales of the product.

The process of obtaining marketing approvals, both in the United States and abroad, is expensive, may take many years if additional clinical trials are required, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. Changes in marketing approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. Regulatory authorities have substantial discretion in the approval process and may refuse to accept any application or may decide that our data is insufficient for approval and require additional preclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate. Any marketing approval we ultimately obtain may be limited or subject to restrictions or post-approval commitments that render the approved product not commercially viable.

If we experience delays in obtaining approval or if we fail to obtain approval of our product candidates, the commercial prospects for our product candidates may be harmed and our ability to generate revenues will be materially impaired. For example, if the regulatory landscape in the United States, Europe or Asia shifts unexpectedly, it may adversely affect the feasibility of study arms, standards of care or statistical assumptions currently reflected in our clinical development plans for CRLX101, potentially delaying the development of CRLX101 in a particular indication and increasing the time required to obtain marketing approval for CRLX101.

Even if we successfully complete the necessary clinical trials for a marketing registration in the U.S., the FDA may convene an advisory committee meeting that could influence their approval decision.

Upon submission of an application for marketing approval in the United States, the FDA may convene an advisory committee (public or closed) to provide the FDA with independent advice from outside experts with specific questions regarding a pending review matter. The opinions or advice expressed by the advisory committee, or any voting decision, are not binding and the FDA retains the ultimate approval power over an application. Regardless of the committee meeting outcome or the FDA’s final approval decision, public presentation of our data may shed positive or negative light on our application. A negative advisory committee meeting could signal a lower likelihood of approval, although the FDA may still end up approving our application. Conversely, an

advisory committee could vote in favor of approval and the FDA may still not approve our application. For an expedited review such as priority review, where the FDA’s oncology office has moved focus to how quickly a drug might be approved and has commonly completed their review and approved products well before the PDUFA goal date, preparations for an ODAC could slow down approval. For us as the applicant, preparation time for an ODAC could take six months or more of dedicated effort by the program team, management, and consultants, in addition to supporting the FDA’s review queries or any other activities in the same timeframe, reducing resource efficiency. It should not be assumed that an application brought in front of the ODAC means that a negative decision is pending. The FDA determines whether or not to have an ODAC meeting depending on the quality of the application, the results of the clinical trials, and whether similar issues, such as endpoints or trial designs, have been previously discussed at these meetings. The FDA has generally taken more problematic or complicated applications to an ODAC, which allows for presentation of their findings and a public discussion of issues at hand. On occasion, the FDA will convene an ODAC to have the public clearly understand their viewpoint on the particular application and its supporting evidence, or if there is a first in class or first in indication compound under review. Development of an NDC such as CRLX101 or CRLX301 may qualify for such a review, although if intended to address an unmet medical need and the data are supportive, the chances of an ODAC are lower.

Failure to obtain marketing approval in foreign jurisdictions would prevent our product candidates from being marketed abroad.

In order to market and sell our products in the European Union and many other jurisdictions, we must obtain separate marketing approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval may differ substantially from that required to obtain FDA approval. The regulatory approval process outside the United States generally includes all of the risks associated with obtaining FDA approval. In addition, in many countries outside the United States, it is required that the product be approved for reimbursement before the product can be approved for sale in that country. We may not obtain approvals from regulatory authorities outside the United States on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside the United States does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. We may not be able to file for marketing approvals and may not receive necessary approvals to commercialize our products in any market.

Even if we obtain marketing approval for our product candidates, the terms of approvals and ongoing regulation of our products may limit how we manufacture and market our products, which could materially impair our ability to generate revenue.

Once marketing approval has been granted, an approved product and its manufacturer and marketer are subject to ongoing review and extensive regulation governing the labeling, packaging, storage and promotion of the product and record keeping and submission of safety and other post-market information.

We must comply with requirements concerning advertising and promotion for any of our product candidates for which we obtain marketing approval. Promotional communications with respect to prescription drugs are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the product’s approved labeling. Thus, we will not be able to promote any products we develop for indications or uses for which they are not approved.

In addition, manufacturers of approved products and those manufacturers’ facilities are required to comply with extensive FDA requirements, including ensuring that quality control and manufacturing procedures conform to cGMPs, which include requirements relating to quality control and quality assurance as well as the corresponding maintenance of records and documentation and reporting requirements. We and our contract manufacturers could be subject to periodic unannounced inspections by the FDA to monitor and ensure compliance with cGMPs.

Accordingly, assuming we receive marketing approval for one or more of our product candidates, we and our contract manufacturers will continue to expend time, money and effort in all areas of regulatory compliance, including manufacturing, production, product surveillance and quality control.

If we are not able to comply with post-approval regulatory requirements, we could have the marketing approvals for our products withdrawn by regulatory authorities and our ability to market any future products could be limited, which could adversely affect our ability to achieve or sustain profitability. Further, the cost of compliance with post-approval regulations may have a negative effect on our operating results and financial condition.

Any product candidate for which we obtain marketing approval could be subject to post-marketing restrictions or withdrawal from the market and we may be subject to substantial penalties if we fail to comply with regulatory requirements or if we experience unanticipated problems with our products, when and if any of them are approved.

Any product candidate for which we obtain marketing approval, along with the manufacturing processes, post-approval clinical data, labeling, advertising and promotional activities for such product, will be subject to continual requirements of and review by the FDA and other regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration and listing requirements, cGMP requirements relating to manufacturing, quality control, quality assurance and corresponding maintenance of records and documents, requirements regarding the distribution of samples to physicians and recordkeeping. Even if marketing approval of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the product may be marketed or to the conditions of approval, including the requirement to implement a risk evaluation and mitigation strategy. New cancer drugs frequently are indicated only for patient populations that have not responded to an existing therapy or have relapsed. If any of our product candidates receives marketing approval, the accompanying label may limit the approved use of our drug in this way, which could limit sales of the product.

The FDA may also impose requirements for costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of the product. The FDA and other agencies, including the Department of Justice, closely regulate the post-approval marketing and promotion of drugs to ensure drugs are marketed only for the approved indications and in accordance with the provisions of the approved labeling. The FDA imposes stringent restrictions on manufacturers’ communications regarding off-label use and if we market our products for unapproved indications, we may be subject to enforcement action for off-label marketing. Violations of the FDA and other statutes, including the False Claims Act, relating to the promotion and advertising of prescription drugs may lead to investigations alleging violations of federal and state health care fraud and abuse laws, as well as state consumer protection laws.

In addition, later discovery of previously unknown adverse events or other problems with our products, manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yield various results, including:

Non-compliance by us or any future collaborator with regulatory requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial penalties. Similarly, failure to comply with regulatory requirements regarding the protection of personal information can also lead to significant penalties and sanctions.

Our relationships with healthcare providers, physicians, and third party payors will be subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which, in the event of a violation, could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings.

Healthcare providers, physicians and third party payors will play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our future arrangements with healthcare providers, physicians, and third party payors may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute any products for which we obtain marketing approval. Restrictions under applicable federal and state healthcare laws and regulations, include the following:

Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government and may require drug product manufacturers to report information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

If our operations are found to be in violation of any of the laws described above or any governmental regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations. Any penalties, damages, fines, curtailment or restructuring of our operations could adversely affect our financial results. If any such actions are instituted against us and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines or other sanctions.

Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, imprisonment, exclusion of products from government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any of the physicians or other healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

Current and future legislation may increase the difficulty and cost for us to obtain marketing approval of and commercialize our product candidates and affect the prices we may obtain.

In the United States and some non-U.S. jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product candidates, restrict or regulate post-approval activities and affect our ability to profitably sell any product candidates for which we obtain marketing approval. Third-party payors are increasingly challenging the prices charged for medical products and services and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. If these third-party payors do not consider our products, if approved, to be cost-effective compared to other available therapies, they may not cover our product after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to realize a meaningful return on our investment. The United States government, state legislatures and non-U.S. governments have shown significant interest in implementing cost containment programs to limit the growth of government-paid health care costs, including price controls, restrictions on reimbursement and requirements for substitution of generic products for branded prescription drugs. Adoption of such controls and measures, and tightening of restrictive policies in jurisdictions with existing controls and measures, could limit payments for our products, if approved.

As a result, the marketability of our products, if approved, could suffer if the government and third-party payors fail to provide adequate coverage and reimbursement. In addition, an increasing emphasis on managed care in the United States has increased and will continue to increase the pressure on drug pricing. Coverage policies, third-party reimbursement rates and drug pricing regulation may change at any time. Even if favorable coverage and reimbursement status is attained for one or more of our products that receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

In the United States, the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, or the MMA, changed the way Medicare covers and pays for pharmaceutical products. The legislation expanded Medicare coverage for drug purchases by the elderly and introduced a new reimbursement methodology based on average sales prices for physician-administered drugs. In addition, this legislation provided authority for limiting the number of drugs that will be covered in any therapeutic class. Cost reduction initiatives and other provisions of this legislation could decrease the coverage and price that we receive for any approved products. While the MMA applies only to drug benefits for Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates. Therefore, any reduction in reimbursement that results from the MMA may result in a similar reduction in payments from private payors.

In March 2010, President Obama signed into law the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Affordability Reconciliation Act, or collectively the PPACA. Among the provisions of the PPACA of potential importance to our business and our product candidates are the following.

In addition, other legislative changes have been proposed and adopted since the PPACA was enacted. These changes included aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, starting in 2013. 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. These new laws may result in additional reductions in Medicare and other healthcare funding.

We expect that the PPACA, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we receive for any approved product. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability, or commercialize our products.

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products. We cannot be sure whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals of our product candidates, if any, may be. In addition, increased scrutiny by the United States Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing testing and other requirements.

Governments outside the United States tend to impose strict price controls, which may adversely affect our revenues from the sales of our products, if any.

In some countries, particularly the countries of the European Union, the pricing of prescription pharmaceuticals 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 product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be harmed, possibly materially.

Our employees may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements, which could cause significant liability for us and harm our reputation.

We are exposed to the risk of employee fraud or other misconduct, including intentional failures to comply with FDA regulations or similar regulations of comparable non-U.S. regulatory authorities, provide accurate information to the FDA or comparable non-U.S. regulatory authorities, comply with manufacturing standards we have established, comply with federal and state healthcare fraud and abuse laws and regulations and similar laws and regulations established and enforced by comparable non-U.S. regulatory authorities, report financial information or data accurately or disclose unauthorized activities to us. Employee misconduct could also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and serious harm to our reputation. It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws, standards or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business and results of operations, including the imposition of significant fines or other sanctions.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could harm our business.

We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals and biological materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties for failure to comply with such laws and regulations.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive materials.

In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Our failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

We are in a period of transition following the appointment of our new president and chief executive officer.

On March 20, 2015, our board of directors appointed Christopher D.T. Guiffre as our President and Chief Executive Officer and elected him as a director, effective immediately. We anticipate that we will experience a transitional period as Mr. Guiffre becomes fully integrated into his new role.

If Mr. Guiffre unexpectedly ceases to fulfill his responsibilities, our business, financial condition, and results of operations could be materially and adversely affected.

Paul A. Friedman, M.D., a member of our board of directors, was appointed Executive Chairman of our board effective October 29, 2014 and we anticipate that he will continue in that role for a temporary period.

Our future success depends on our ability to retain key executives and to attract, retain and motivate qualified personnel.

We are highly dependent on our executive team, most of whom have been employed by the company for two years or less. The loss of any member of the executive team could impede the achievement of our goals. Any of our employees may terminate their employment with us at any time. We do not maintain “key person” insurance for any of our executives or other employees.

Recruiting and retaining qualified scientific, clinical, manufacturing finance and sales and marketing personnel will also be critical to our success. The loss of the services of key employees could impede the achievement of our research, development and commercialization objectives and seriously harm our ability to successfully implement our business strategy. Furthermore, replacing executive officers and key employees, including finance and clinical personnel, may be difficult and may take an extended period of time because of the limited number of individuals in our industry with the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize products. Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or motivate these key personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. We also experience competition for the hiring of scientific personnel from universities and research institutions. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategy. Our consultants and advisors may be employed by employers other than us and may have commitments under consulting or advisory contracts with other entities that may limit their availability to us.

We expect to expand our development and regulatory capabilities and potentially implement sales, marketing and distribution capabilities, and as a result, we may encounter difficulties in managing our growth, which could disrupt our operations.

We expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of drug development, regulatory affairs and, if any of our product candidates receives marketing approval, sales, marketing and distribution. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

We relocated our operations to Waltham, Massachusetts in late December 2015. The process of relocating our facilities could have disrupted our operations, adversely affected our business or damaged employee morale.

We entered into a new lease dated as of July 9, 2015 with AstraZeneca Pharmaceuticals Limited Partnership for approximately 22,992 square feet at the BioHub at 35 Gatehouse Drive in Waltham, Massachusetts. The term of the new lease commenced on December 28, 2015 and expires on February 28, 2021. The lease for our laboratory and office space in Cambridge, Massachusetts was scheduled to expire on February 29, 2016. However, we amended that lease so that it terminated as of December 31, 2015. Although the relocation process is substantially complete, it will take time before we know whether it disrupted our operations, adversely affected our business or damaged employee morale.

The market price of our common stock has been and may in the future be volatile and fluctuate substantially.

Our stock price has been and may in the future be volatile. From April 10, 2014 to December 31, 2015, the closing price of our common stock as reported by the NASDAQ Global Market ranged from a high of $10.87 per share to a low of $2.80 per share. The stock market in general and the market for biopharmaceutical companies in particular have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. The market price for our common stock may be influenced by many factors, including:

In addition, the stock market in general and the market for biotechnology and biopharmaceutical companies in particular have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of those companies. These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance. In the past, following periods of volatility in companies’ stock prices, securities class-action litigation has often been instituted against such companies. Such litigation, if instituted against us, could result in substantial costs and diversion of management’s attention and resources, which could materially and adversely affect our business and financial condition.

Our executive officers and directors and their affiliates own a significant percentage of our stock and will be able to exercise significant influence over matters submitted to stockholders for approval.

We believe that as of December 31, 2015, our executive officers and directors and their affiliates beneficially owned 27.9% of our outstanding common stock. As a result, if these stockholders were to choose to act together, they would be able to exert a significant degree of influence over matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would substantially influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets.

Although we have listed our common stock on The NASDAQ Global Market, an active trading market for our shares may not be sustained. In the absence of an active trading market for our common stock, it may be difficult for our stockholders to sell their shares without depressing the market price for the shares or sell their shares at or above the prices at which they acquired their shares or sell their shares at the times they would like to sell. An inactive trading market for our common stock may also impair our ability to raise capital to continue to fund our operations by selling shares and may impair our ability to acquire other companies or technologies by using our shares as consideration.

A significant portion of our total outstanding shares may be sold into the public market at any point, which could cause the market price of our common stock to drop significantly, even if our business is doing well.

Sales of a substantial number of shares of our common stock in the public market could occur at any time. These sales, or the perception in the market that holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. Our outstanding shares of common stock may be freely sold in the public market at any time to the extent permitted by Rules 144 and 701 under the Securities Act of 1933, as amended, which we refer to as the Securities Act, or to the extent such shares have already been registered under the Securities Act and are held by non-affiliates of ours.

As of December 31, 2015, there were 3,454,926 shares subject to outstanding options. In August 2014, we registered all of these shares under the Securities Act on a registration statement on Form S-8. These shares can be freely sold in the public market upon exercise, as permitted by any applicable vesting requirements, except to the extent they are held by our affiliates, in which case such shares will become eligible for sale in the public market as permitted by Rule 144 under the Securities Act. Furthermore, as of December 31, 2015, there were 300,564 shares subject to outstanding warrants to purchase common stock. These shares will become eligible for sale in the public market, to the extent such warrants are exercised, as permitted by Rule 144 under the Securities Act. Moreover, holders of approximately [6.3 million shares] of our common stock have rights, subject to conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or other stockholders.

We have broad discretion in the use of our cash reserves and may not use them effectively.

Our management has broad discretion to use our cash reserves and could use our cash reserves in ways that do not improve our results of operations or enhance the value of our common stock. The failure by our management to apply these funds effectively could result in financial losses and these financial losses could have a material adverse effect on our business, cause the price of our common stock to decline and delay the development of our product candidates. Pending their use, we may invest our cash reserves in a manner that does not produce income or that loses value.

We are an “emerging growth company,” and the reduced disclosure requirements applicable to emerging growth companies may make our common stock less attractive to investors.

We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and may remain an emerging growth company through 2019. For so long as we remain an emerging growth company, we are permitted and intend to rely on exemptions from certain disclosure requirements that are applicable to other public companies that are not emerging growth companies. These exemptions include:

We may choose to take advantage of some, but not all, of the available exemptions. We cannot predict whether investors will find our common stock less attractive if we rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

In addition, the JOBS Act also provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. This allows an emerging growth company to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have irrevocably elected not to avail ourselves of this exemption from new or revised accounting standards and, therefore, we are subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

We are currently incurring and expect to continue to incur increased costs as a result of operating as a public company, and our management will be required to devote substantial time to new compliance initiatives and corporate governance practices.

As a newly public company, we are incurring and expect to continue to incur additional significant legal, accounting and other expenses that we did not incur as a private company. We expect that these expenses will further increase after we are no longer an “emerging growth company.” We expect that we will need to hire additional accounting, finance and other personnel in connection with our continuing efforts to comply with the requirements of being a public company, and our management and other personnel will need to continue to devote a substantial amount of time towards maintaining compliance with these requirements. In addition, the Sarbanes-Oxley Act of 2002 and rules subsequently implemented by the Securities and Exchange Commission and NASDAQ have imposed various requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our management and other personnel will need to devote a substantial amount of time to these compliance initiatives. Moreover, these rules and regulations will increase our legal and financial compliance costs and will make some activities more time-consuming and costly.

Pursuant to Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, we will be required to furnish a report by our management on our internal control over financial reporting, including an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. However, while we remain an emerging growth company, we will not be required to include an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. To achieve compliance with Section 404 within the prescribed period, we will be engaged in a process to document and evaluate our internal control over financial reporting, which is both costly and challenging. In this regard, we will need to continue to dedicate internal resources, potentially engage outside consultants and adopt a detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes as appropriate, validate through testing that controls are functioning as documented and implement a continuous reporting and improvement process for internal control over financial reporting. If we identify one or more material weaknesses, it could result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of our financial statements.

Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any, will be your sole source of gain.

We have never declared or paid cash dividends on our capital stock. We currently plan to retain all of our future earnings, if any, to finance the growth and development of our business. Furthermore, the terms of the Hercules Loan Agreement prohibit us from paying any dividends without the prior written consent of Hercules, and any future debt agreements may also preclude us from paying dividends. Accordingly, capital appreciation, if any, of our common stock will be the sole source of gain for our stockholders for the foreseeable future.

Provisions in our certificate of incorporation, our by-laws or Delaware law might discourage, delay or prevent a change in control of our company or changes in our management and, therefore, depress the trading price of our common stock.

Provisions in our certificate of incorporation, our bylaws or Delaware law may discourage, delay or prevent a merger, acquisition or other change in control that stockholders may consider favorable, including transactions in which our stockholders might otherwise receive a premium for their shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions might frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions:

In addition, we are governed by Section 203 of the Delaware General Corporation Law, which prohibits a publicly-held Delaware corporation from engaging in a business combination with an interested stockholder, generally a person which 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. This could discourage, delay or prevent someone from acquiring or merging with us, whether or not it is desired by, or beneficial to, our stockholders.

If securities analysts do not publish research or reports about our business or if they publish negative evaluations of our stock, the price of our stock could decline.

The trading market for our common stock relies in part on the research and reports that industry or financial analysts publish about us or our business. We do not have any control over these analysts. If one or more of the analysts covering our business downgrade their evaluations of our stock, the price of our stock could decline. In addition, if one or more of these analysts cease coverage of our company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which in turn could cause our stock price or trading volume to decline.

Our principal facilities consist of approximately 23,000 square feet of office, laboratory and vivarium space located at 35 Gatehouse Drive, Waltham, Massachusetts. The lease expires in February 2021, subject to our option to extend the lease for an additional three years.

In March 2014, Calando Pharmaceuticals, Inc., or Calando, entered Chapter 7 bankruptcy in the District of Delaware and, as a result, the intellectual property rights we have obtained from Calando are subject to potential risks that may arise in connection with bankruptcy. For instance, while our ability to develop and/or commercialize our current product candidates and our ability to utilize our platform are not dependent on the rights that we license from Calando, our license agreements with Calando could be rejected in connection with Calando’s bankruptcy, in which case, we could, subject to elections and other rights and defenses that may be available to us, lose certain rights granted to us under such licenses. On March 27, 2015, the bankruptcy court granted Calando’s bankruptcy trustee’s application to retain a broker to help sell Calando’s rights in certain assets including its rights in the license agreements with Cerulean. We reserved our rights with respect to any such sale.

Our common stock has been listed on the NASDAQ Global Market under the symbol “CERU” since April 2014. The following table sets forth on a per share basis, for the periods indicated, the low and high sale prices of our common stock as report by the NASDAQ Global Market.

As of the close of business on March 1, 2016, there were approximately 43 holders of record of our common stock.

We have never declared or paid cash dividends on our common stock. We currently intend to retain any current and future earnings to finance the growth and development of our business and, therefore, do not anticipate paying any cash dividends in the foreseeable future. Our amended and restated credit facility contains restrictions on our ability to pay dividends.

We completed the initial public offering of our common stock, or our IPO, pursuant to a Registration Statement on Form S-1 (File No. 333-194442), which was declared effective by the United States Securities and Exchange Commission, or SEC, on April 10, 2014. The net offering proceeds to us, after deducting underwriting discounts and commissions and offering expenses, were approximately $59.9 million.

As of December 31, 2015, we had used approximately $40.9 million of the net proceeds from our IPO, primarily to fund the clinical development of CRLX101, to fund research and development of CRLX301 and for working capital and other general corporate purposes. We have invested the balance of the net proceeds from the offering in a variety of capital preservation investments, including short-term, investment grade, interest bearing instruments and U.S. government securities in accordance with our investment policy. There has been no material change in our planned use of the net proceeds from our IPO as described in our final prospectus filed with the SEC pursuant to Rule 424(b)(4) under the Securities Act.

This performance graph shall not be deemed “soliciting material” or to be “filed” with the SEC for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or the Exchange Act, or otherwise subject to the liabilities under that section, and shall not be deemed to be incorporated by reference into any filing of our company under the Securities Act of 1933, as amended, or the Exchange Act.

The following graph compares the cumulative total return to stockholders for our common stock for the period from April 10, 2014 through December 31, 2015 with The NASDAQ Composite Index and the NASDAQ Biotechnology index. The comparison assumes an investment of $100 is made on April 10, 2014 in our common stock and in each of the indices and in the case of the indices it also assumes reinvestment of all dividends. The performance shown is not necessarily indicative of future performance.

You should read the following selected consolidated financial data in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements and the related notes appearing elsewhere in this Annual Report on Form 10-K. We have derived the consolidated statements of operations data for the years ended December 31, 2015, 2014, and 2013, and the consolidated balance sheet data at December 31, 2015 and 2014 from our audited consolidated financial statements included in this report on Form 10-K. The consolidated statement of operations data for the year ended December 31, 2012, and consolidated balance sheet data as of December 31, 2013 and 2012 are from our audited consolidated financial statements that are not in this Form 10-K. Our historical results for any prior period are not necessarily indicative of the results to be expected in any future period.

	Years Ended December 31,
(in thousands, except share data and per share data)	2015			2014			2013			2012
Consolidated Statement of Operations Data:
Revenue	$	—		$	80		$	6		$	625
Operating expenses:
Research and development		25,948			11,772			9,700			15,807
General and administrative		11,224			8,587			6,166			6,393
Total operating expenses		37,172			20,359			15,866			22,200
Other income (expense):
Interest income		10			9			2			2
Interest expense		(2,432	)		(1,083	)		(1,487	)		(567	)
Loss on extinguishment of debt		—			(2,493	)		—			—
Decrease in value of preferred stock warrant liability		—			504			202			39
Total other (expense)—net		(2,422	)		(3,063	)		(1,283	)		(526	)
Net loss		(39,594	)		(23,342	)		(17,143	)		(22,101	)
Accretion of redeemable convertible preferred stock		—			—			—			(73	)
Net loss attributable to common stockholders	$	(39,594	)	$	(23,342	)	$	(17,143	)	$	(22,174	)
Net loss per share attributable to common stockholders:
Basic and diluted	$	(1.56	)	$	(1.60	)	$	(25.05	)	$	(36.39	)
Weighted-average common shares outstanding:
Basic and diluted		25,431,332			14,548,516			684,330			609,344

	As of December 31,
(in thousands)	2015			2014			2013			2012
Consolidated Balance Sheet Data:
Cash and cash equivalents	$	75,908		$	51,174		$	5,488		$	16,707
Working capital (deficit)	$	60,965		$	44,775		$	(8,699	)	$	10,540
Total assets	$	78,225		$	53,393		$	6,827		$	17,661
Long-term debt (including current portion)	$	20,324		$	3,124		$	6,258		$	9,127
Redeemable convertible preferred stock	$	—		$	—		$	81,525		$	83,751
Common stock	$	3		$	2		$	—		$	—
Additional paid in capital	$	210,115		$	167,104		$	4,140		$	1,257
Accumulated deficit	$	(161,375	)	$	(121,781	)	$	(98,439	)	$	(81,296	)
Total stockholders' equity (deficit)	$	48,743		$	45,325		$	(94,299	)	$	(80,039	)

You should read the following discussion and analysis of our financial condition and results of operations together with our condensed consolidated financial statements and the related notes appearing elsewhere in this Annual Report on Form 10-K. Some of the information contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. You should read the “Risk Factors” section of this Annual Report on Form 10-K for a discussion of important factors that could cause actual results to differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

We are a clinical-stage, oncology-focused company applying our proprietary Dynamic Tumor Targeting™ Platform to develop differentiated therapies. We were incorporated under the laws of the State of Delaware on November 28, 2005, under the name Tempo Pharmaceuticals, Inc. In October 2008, we changed our name to Cerulean Pharma Inc.

Our platform has generated two-clinical stage NDCs. Our first platform-generated clinical candidate, CRLX101, is in Phase 2 clinical development in patients with renal cell carcinoma, or RCC, and in Phase 2 and Phase 1b clinical development in patients with ovarian cancer in combination with Avastin^® (bevacizumab) and paclitaxel, respectively. CRLX101 has been dosed in more than 350 patients and has shown activity in multiple tumor types, both as monotherapy and in combination with other cancer treatments. The United States Food and Drug Administration, or FDA, has granted CRLX101 fast track designation in combination with Avastin in metastatic RCC and orphan drug designation for the treatment of ovarian cancer. Our second platform-generated clinical candidate, CRLX301, is currently in Phase 1/2a clinical development. We intend to generate additional candidates, alone and potentially in collaboration with partners.

We are pursuing development of CRLX101 in combination with anti-cancer therapies in multiple ongoing clinical development programs that include company-sponsored trials and investigator-sponsored trials, or ISTs. Our two lead indications are RCC, or kidney cancer, and ovarian cancer:

In November 2015, we entered into a collaboration with AstraZeneca AB, or AstraZeneca, and the National Cancer Institute, or the NCI, to study the clinical combination of AstraZeneca’s drug Lynparza^® (olaparib) with CRLX101. We believe our NDCs enable therapeutic combinations because they are designed to concentrate anti-cancer payloads inside tumor cells and spare healthy tissue. Preclinical data generated by AstraZeneca with the Lynparza-CRLX101 combination demonstrated a synergistic anti-tumor effect from targeting two validated pathways. While PARP-topo 1 combinations have traditionally been limited by toxicity, we believe that with our NDC and the work AstraZeneca has done to define a clinical dose and schedule, we may be able to develop an effective and tolerable Lynparza-CRLX101 combination.

We hold issued patents in the United States, Japan, and several other countries covering the composition of matter of CRLX101 that expire in 2023 and 2024, excluding any potential patent term extension. Due to the ability of NDCs to target the “leaky” vasculature that is present in all solid tumors and CRLX101’s apparently favorable adverse event profile observed to date, we believe CRLX101 may have significant clinical utility in several cancer indications, particularly in combination with other cancer therapies. We hold issued patents in the United States, Japan, and several other countries covering the composition of matter of CRLX301 that expire in 2023 and 2024, excluding any potential patent term extension.

To date, we have devoted substantially all of our resources to our drug discovery and development efforts, including conducting clinical trials of our product candidates, protecting our intellectual property and the general and administrative support of our operations. We have generated no revenue from product sales. We expect that it will be several years before we commercialize a product candidate, if ever. Through December 31, 2015, we have funded our operations primarily through $84.2 million in proceeds from the sale of shares of our convertible preferred stock in private placements, net proceeds of $59.9 million from sales of shares of our common stock in our initial public offering, or IPO, net proceeds of $37.2 million from the sale of shares of our common stock in April 2015 in an underwritten public offering, $17.3 million in proceeds from our sale of convertible promissory notes, $10.0 million in proceeds from a loan and security agreement with Lighthouse Capital Partners VI, L.P., or Lighthouse Capital, and $21.0 million in proceeds from a loan and security agreement with Hercules Technology Growth Capital, Inc., or Hercules. We refer to our loan and security agreements with Lighthouse Capital and Hercules as the Lighthouse Loan Agreement and the Hercules Loan Agreement, respectively.

On January 8, 2015, we entered into the Hercules Loan Agreement. Pursuant to the Hercules Loan Agreement, we are eligible to borrow up to an aggregate principal amount of $26.0 million, subject to certain conditions. On January 8, 2015, we borrowed $15.0 million under the Hercules Loan Agreement, and we used a portion of those proceeds to repay our outstanding indebtedness under the Lighthouse Loan Agreement. In connection with entering into the Hercules Loan Agreement, we sold 135,501 shares of our common stock to Hercules in a private placement and received $1.0 million in proceeds. On November 24, 2015, we drew a second tranche in the amount of $6.0 million under the Hercules Loan Agreement. We elected not to commence a randomized Phase 2 clinical trial of CRLX101 in combination with chemoradiotherapy on or prior to December 15, 2015, which was a condition of obtaining an additional tranche in an amount of up to $5.0 million. As a result, we are no longer eligible to borrow this amount under the Hercules Loan Agreement. At December 31, 2015, the total principal amount due under the Hercules Loan Agreement was $21.0 million.

We have never been profitable and have incurred significant operating losses since our incorporation. As of December 31, 2015, we had an accumulated deficit of $161.4 million. We incurred net losses of approximately $39.6 million, $23.3 million, and $17.1 million for the years ended December 31, 2015, 2014 and 2013, respectively.

We expect to continue to incur significant and increasing expenses and operating losses for the foreseeable future, as we advance our product candidates through preclinical studies and clinical trials, and as we eventually seek regulatory approval for, and commercialize, our product candidates. Our net losses may fluctuate significantly from quarter to quarter and from year to year. We will need to raise additional capital in the future to support our expenses and operating activities.

To date, we have not generated any revenue from product sales and do not expect to generate any revenue from product sales for the next several years, if ever. In the future, we may generate revenue from a combination of product sales, license fees, milestone and research and development payments in connection with strategic partnerships, and royalties resulting from the sales of products developed under licenses of our intellectual property. We expect that any revenue we generate will fluctuate from quarter to quarter as a result of the timing and amount of any such payments. Our ability to generate product revenues will depend on the successful development and eventual commercialization of our product candidates. If we fail to complete the development of our product candidates in a timely manner or to obtain regulatory approval for our product candidates, our ability to generate future revenue and our results of operations and financial position would be materially adversely affected.

To date, our only revenue has consisted of a government tax credit that we received in 2010 and payments in each of the years from 2011 through 2014 from four material transfer agreements and a research agreement.

Research and development expense consists of costs incurred in connection with the discovery and development of our Dynamic Tumor Targeting Platform and our NDCs. These expenses consist primarily of:

Conducting a significant amount of research and development is central to our business model. Product candidates in late stages of clinical development generally have higher development costs than those in earlier stages of clinical development primarily due to the increased size and duration of late-stage clinical trials. We plan to increase our research and development expenses for the foreseeable future as we continue to support multiple clinical trials of CRLX101 and CRLX301, and advance our earlier-stage research and development projects.

We use our employee and infrastructure resources across multiple research and development programs. We track external research and development expenses and personnel expense on a program-by-program basis and have allocated expenses such as stock-based compensation and indirect laboratory supplies and services to each program based on the personnel resources allocated to each program. Facilities, depreciation and scientific advisory board fees and expenses are not allocated to a program and are considered overhead. Below is a summary of our research and development expenses for the years ended December 31, 2015, 2014 and 2013 (in thousands):

Our lead product candidate, CRLX101, is an NDC in Phase 2 clinical development. We are pursuing development of CRLX101 in combination with anti-cancer therapies in multiple ongoing clinical development programs that include company-sponsored trials and ISTs. The leading CRLX101 development programs are:

Additional trials involving CRLX101 are also ongoing, including a Phase 1b/2 IST in locally advanced rectal cancer and a Phase 1b company-sponsored trial exploring a dose-intensive schedule for CRLX101 in patients with solid tumors.

We cannot accurately project future research and development expenses for our CRLX101 program because such expenses are dependent on a number of variables, including, among others, the cost and design of any additional clinical trials, the duration of the regulatory process and the results of any clinical trials.

Under our license agreement with Calando Pharmaceuticals, Inc., or Calando, pursuant to which we obtained rights to CRLX101, or the CRLX101 Agreement, we are obligated to pay milestone payments which could total, in the aggregate, $32.8 million, if we achieve certain development and sales events with CRLX101. In addition, under the CRLX101 Agreement, if we, or one of our affiliates, sell CRLX101, we are required to pay tiered royalty payments ranging from low- to mid-single digits, as a percentage of worldwide net sales, depending on whether there is patent protection for CRLX101 at the time of the sale. In the event we license or sublicense the intellectual property that we purchased or licensed from Calando, we are required to pay Calando a percentage of the income we receive from the licensee or sublicensee to the extent attributable to such license or sublicense, subject to certain exceptions. The percentage of such license income that we are obligated to pay Calando ranges from the low- to mid-double digits depending on the development stage of CRLX101 at the time we first provide or receive draft terms of a license arrangement with the third party that results in a license agreement.

We are studying CRLX301 in a Phase 1/2a trial in patients with advanced solid tumor malignancies in order to evaluate the safety of the drug and establish an MTD for two dosing schedules. We explored tolerability of dose ranges when the drug candidate was administered once every three weeks and have determined an MTD for this dosing schedule. We are exploring a weekly dosing schedule to determine the MTD for that regimen. These parallel paths will allow us to determine the recommended Phase 2 dose with the preferred dosing schedule.

Under our license agreement with Calando pursuant to which we obtained rights to Calando’s cyclodextrin system for purposes of conjugating or complexing certain other therapeutic agents to the system, or the Platform Agreement, we paid a $250,000 clinical development milestone to Calando in January 2015 in connection with the initiation of our Phase 1/2a clinical trial of CRLX301 in December 2014. We are also required to make milestone payments in an aggregate amount of up to approximately $18.0 million to Calando if we achieve certain development and sales events with respect to CRLX301. Further, under the Platform Agreement, if we, or one of our affiliates, sell CRLX301 we are required to pay tiered royalty payments ranging from low- to mid-single digits, as a percentage of worldwide net sales, depending on whether there is patent protection at the time of the sale. In the event we license or sublicense the intellectual property that we purchased or licensed from Calando, we are required to pay Calando a percentage of the income we receive from the licensee or sublicensee to the extent attributable to such license or sublicense, subject to certain exceptions. The percentage of such license income that we are obligated to pay Calando is in the low-double digits.

We expect that the expenses related to our NDCs and the development of our platform will continue to increase as we seek to identify additional targets for preclinical research and add personnel to these projects. We cannot accurately predict future research and development expenses for our NDCs because such costs are dependent on a number of variables, including the success of preclinical studies on any such NDC.

The successful development of any of our NDCs is highly uncertain. As such, at this time, we cannot reasonably predict with certainty the duration and costs of the current or future preclinical studies or clinical trials of any of our NDCs or if, when or to what extent we will generate revenues from any commercialization and sale of any of our NDCs that obtain marketing approval. We may never succeed in achieving regulatory approval for any of our NDCs. The duration, costs and timing of development of our NDCs will depend on a variety of factors, including:

Any change in the outcome of any of these variables with respect to the development of an NDC could mean a significant change in the cost and timing associated with the development of that NDC. For example, if the FDA, or a comparable non-U.S. regulatory authority were to require us to conduct clinical trials beyond those that we currently anticipate will be required for the marketing authorization of an NDC, or if we experience significant delays in enrollment in any of our clinical trials, we could be required to expend significant additional financial resources and time to obtain marketing authorization.

As a result of the uncertainties discussed above, we are unable to determine when, or to what extent, we will generate revenues from the commercialization and sale of any of our NDCs. We anticipate that we will make determinations as to which additional programs to pursue and how much funding to direct to each program on an ongoing basis in response to the scientific and clinical data with respect to each NDC, as well as our ongoing assessment of the NDCs’ commercial potential. We will need to raise additional capital in the future in order to complete the development and commercialization of CRLX101 and CRLX301 and to fund the development of our other NDCs, if any.

General and administrative expenses consist principally of salaries and related costs for personnel in our executive, finance, business development, marketing, legal and human resources functions. Other general and administrative expenses include patent filing, patent prosecution, professional fees for legal, insurance, consulting, information technology, auditing and tax services and facility costs not otherwise included in research and development expenses.

We anticipate that our general and administrative expenses will increase in the future for, among others, the following reasons:

Interest income consists of interest earned on our cash and cash equivalents. The primary objective of our investment policy is capital preservation.

Interest expense consists primarily of interest, amortization of debt discount and amortization of deferred financing costs associated with the Hercules Loan Agreement. Interest expense also includes the write off of debt discount and deferred financing costs associated with the repayment in 2015 of the debt incurred under the Lighthouse Loan Agreement. In 2014, interest expense consisted primarily of interest, amortization of debt discount and amortization of deferred financing costs associated with the Lighthouse Loan Agreement and interest expense on our convertible notes.

Loss on extinguishment of debt is associated with the loss recorded on the conversion of the convertible notes we issued in 2014, or the 2014 Convertible Notes. The loss is an amount equal to the difference between the fair value of shares of our common stock into which the 2014 Convertible Notes converted and the carrying amount of the 2014 Convertible Notes at the closing of the IPO on April 15, 2014.

The preferred stock warrant liability is associated with warrants to purchase shares of our preferred stock issued to lenders and investors. The change in fair value consists of the calculated change in value based upon the fair value of the underlying security at the end of each reporting period as calculated using the Black-Scholes option-pricing model. The preferred stock warrants were automatically adjusted on the date of the closing of the IPO, April 15, 2014, to provide for the issuance of shares of common stock upon their exercise. The preferred stock warrant liability has been reclassified to additional paid-in capital as of April 15, 2014.

Our management’s discussion and analysis of our financial condition and results of operations are based on our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States. The preparation of these consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. On an ongoing basis, we evaluate our estimates and judgments, including those related to accrued expenses and stock-based compensation. We base our estimates on historical experience, known trends and events and various other factors that we believe to be 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. Actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimates in light of changes in circumstance, facts and experience. The effects of material revisions in estimates, if any, will be reflected in the consolidated financial statements prospectively from the date of change in estimates.

Our significant accounting policies are described in more detail in Note 2 of the notes to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K. We believe the following accounting policies are critical to the judgments and estimates used in the preparation of the consolidated financial statements.

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued expenses. This process involves reviewing open contracts and purchase orders, communicating with applicable personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual cost. The majority of our service providers invoice us monthly in arrears for services performed. We make estimates of our accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us at that time. We periodically confirm the accuracy of our estimates with the service providers and make adjustments if necessary. Examples of estimated accrued clinical expenses include:

We base our expenses related to clinical trials on our estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and CROs that conduct and manage clinical trials on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing the service fees, we consider the terms of each agreement, the time period over which the services will be performed and the level of effort required to complete the service. If the actual timing of the performance of the services or the level of effort varies from our estimate, we adjust the accrual accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in us reporting amounts that are too high or too low in any particular period. We have not experienced any significant adjustments to our estimates to date.

We issue stock-based awards to employees and non-employees in the form of stock options. We apply the fair value recognition provisions of the Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or ASC, Topic 718, Compensation-Stock Compensation, or ASC 718. ASC 718 requires all stock-based payments to employees, including grants of employee stock options and modifications to existing stock options, to be recognized in the consolidated statements of operations based on their fair values. We account for stock-based awards to non-employees in accordance with FASB ASC Topic 515-50, Equity-Based Payments to Non-Employees, which requires the fair value of the award to be re-measured at fair value as the award vests. We recognize the compensation expense of stock-based awards on a straight-line basis over the vesting period of the award for employees and non-employees. We have issued performance-based grants where the vesting of the grant is tied to certain milestone performance and, in these cases, the compensation is recognized as expense when the probability of the milestone is met. Compensation expense related to our stock-based awards is subject to a number of estimates, including the estimated volatility and underlying fair value of our common stock, as well as the estimated life of the awards. We estimate the fair value of our stock-based awards for recording stock-based compensation expense using the Black-Scholes option pricing model. Determining the appropriate fair value model and calculating the fair value of stock-based awards requires significant judgment and the use of assumptions.

Prior to our IPO, we were a private company with no active public market for our common stock. Therefore, we periodically determined for financial reporting purposes the estimated per share fair value of our common stock at various dates using contemporaneous valuations performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation. We performed these contemporaneous valuations as of December 31, 2011, December 1, 2012, September 30, 2013 and December 31, 2013. In conducting the contemporaneous valuations, we considered all objective and subjective factors that we believed to be relevant for each valuation conducted, including our best estimate of our business condition, prospects and operating performance at each valuation date.

Since our IPO, we have determined the fair value of our common stock based on the closing price of our common stock on The NASDAQ Global Market on the applicable date of such grant.

The following table summarizes our consolidated results of operations for the years ended December 31, 2015 and 2014, together with the changes in those items in dollars and as a percentage (in thousands, except percentages):

	Years Ended December 31,						Change
	2015			2014			Dollar			%
Revenue	$	—		$	80		$	(80	)		-100	%
Operating expenses:
Research and development		25,948			11,772			14,176			120	%
General and administrative		11,224			8,587			2,637			31	%
Loss from operations		(37,172	)		(20,279	)		(16,893	)		83	%
Other expense, net		(2,422	)		(3,063	)		641			-21	%
Net loss	$	(39,594	)	$	(23,342	)	$	(16,252	)		70	%

Revenue. There was no revenue recorded for the year ended December 31, 2015. For the year ended December 31, 2014, we recorded revenue of $80,000 from payments we received under two material transfer agreements. Pursuant to the agreements, we received payments in exchange for providing research services utilizing our proprietary technology. Work under the agreements terminated in 2014.

Research and development. Research and development expense for the year ended December 31, 2015, was $25.9 million compared to $11.8 million for the year ended December 31, 2014, an increase of $14.1 million, or 120%. The increase was primarily attributable to an increase in costs associated with the CRLX101 program. The following table summarizes our research and development expense by program for the years ended December 31, 2015 and 2014, together with the change in spending by program in dollars and as a percentage (in thousands, except percentages):

For the year ended December 31, 2015, CRLX101 program expenses increased by $11.8 million, or 163%, to $19.0 million compared to $7.2 million for the year ended December 31, 2014. The increase in CRLX101 program expense was primarily attributable to costs associated with our ongoing RCC Trial, which was initiated in mid-2014. Additional CRLX101 costs include costs associated with ongoing ISTs in addition to costs associated with clinical trials initiated in 2015 including our Phase 1b single-arm, company-sponsored trial of CRLX101 in combination with weekly paclitaxel in patients with relapsed ovarian cancer and our Phase 1 trial exploring a dose-intensive schedule for CRLX101 in patients with advanced solid tumor malignancies. Clinical trial expenses increased $6.5 million reflecting an increase in CRO fees, investigator fees and costs associated with clinical sites and laboratories. Salary and benefits expenses increased $2.0 million and consulting costs increased $0.8 million compared to the prior year to support the CRLX101 development program and the clinical trials. Chemistry, manufacturing and controls costs increased $2.2 million compared to the prior year reflecting increased activity to support current and future clinical development of CRLX101.

For the year ended December 31, 2015, CRLX301 program expenses increased $1.0 million, or 42%, to $3.4 million compared to $2.4 million for the year ended December 31, 2014. The increase in CRLX301 program expenses was primarily due to costs associated with the Phase 1/2a clinical trial that we initiated in December 2014. CRLX301 clinical trial expenses increased by $0.5 million for the year ended December 31, 2015, compared to the prior year primarily due to CRO fees, costs associated with clinical sites and laboratory costs. Salary and benefits expenses increased $0.5 million and consulting costs increased $0.2 million to support the CRLX301 program development and the clinical trials. The increase in costs associated with the CRLX301 program were partially offset by a milestone fee of $0.3 million paid to Calando upon initiation of the CRLX301 clinical trial in 2014 compared to no milestone fee in 2015.

Expenses associated with our Dynamic Tumor Targeting Platform were $2.1 million for the year ended December 31, 2015, an increase of $0.9 million, or 74%, compared to $1.2 million for the year ended December 31, 2014. The increase is primarily due to increased headcount and lab costs in new discovery research. Overhead costs increased $0.5 million, or 54%, to $1.4 million compared to $0.9 million for the year ended December 31, 2014. The increase was primarily attributable to increases in facility and depreciation costs of $0.2 million, recruiting and employee costs of $0.2 million and other costs of $0.1 million not allocated to programs.

General and administrative. General and administrative expense for the year ended December 31, 2015, was $11.2 million compared to $8.6 million for the year ended December 31, 2014, an increase of $2.6 million, or 31%. The increase in general and administrative costs was attributable to the growth in our corporate infrastructure to support our increased size as well as requirements resulting from our being a public company. Salaries and benefits, including stock-based compensation, increased $2.1 million for the year ended December 31, 2015, compared to the prior year, reflecting increases in finance and accounting, legal and corporate communications staffing. Other general and administrative expenses including professional services and consulting, facility and office expenses, dues and subscriptions, conference and travel expenses increased $0.2 million for the year ended December 31, 2015, compared to the prior year due to our overall growth.

Other expense, net. Other expense, net, for the year ended December 31, 2015, was $2.4 million compared to $3.1 million for the year ended December 31, 2014, a decrease of $0.7 million, or 21%. The decrease in other expense, net, was primarily due to a $2.5 million loss on the conversion of the 2014 Convertible Notes, which was recorded in April 2014. Interest expense was $2.4 million and $1.1 million for the years ended December 31, 2015 and 2014, respectively, an increase of $1.3 million, or 121%. For the year ended December 31, 2015, interest expense included $2.1 million associated with the Hercules Loan Agreement, including $0.5 million for the amortization of debt discount and deferred financing costs, and $0.2 million for the write off of debt discount and deferred financing costs associated with the repayment of the Lighthouse Loan Agreement. Interest expense for the year ended December 31, 2014, included $0.3 million of interest on our convertible notes and $0.6 million of interest and $0.2 million for

amortization of debt discount and deferred financing costs associated with the Lighthouse Loan Agreement. Other expense, net, for the year ended December 31, 2014, included a $0.5 million adjustment to the fair value of our outstanding preferred stock warrant liability which was recorded as other income.

The following table summarizes our consolidated results of operations for the years ended December 31, 2014 and 2013, together with the changes in those items in dollars and as a percentage (in thousands, except percentages):

	Years Ended December 31,						Change
	2014			2013			Dollar			%
Revenue	$	80		$	6		$	74			1233	%
Operating expenses:
Research and development		11,772			9,700			2,072			21	%
General and administrative		8,587			6,166			2,421			39	%
Loss from operations		(20,279	)		(15,860	)		(4,419	)		28	%
Other expense, net		(3,063	)		(1,283	)		(1,780	)		139	%
Net loss	$	(23,342	)	$	(17,143	)	$	(6,199	)		36	%

Revenue. For the year ended December 31, 2014 revenue was $80,000 compared to $6,000 for the year ended December 31, 2013. For both periods, revenue is from two material transfer agreements and reflects timing of activity and payments received under the agreements.

Research and development. The following table summarizes our research and development expense by program for the years ended December 31, 2014 and 2013, together with the change in spending by program in dollars and as a percentage (in thousands, except percentages):

Research and development expense for the year ended December 31, 2014, was $11.8 million compared to $9.7 million for the year ended December 31, 2013, an increase of $2.1 million, or 21%. The increase was primarily attributable to an increase in costs associated with the CRLX101 program and partially offset by lower costs associated with our Dynamic Tumor Targeting Platform new discovery research.

For the year ended December 31, 2014, costs associated with the CRLX101 program increased $2.6 million, or 55%, to $7.2 million from $4.6 million for the year ended December 31, 2013. The increase was primarily due to ongoing costs associated with the RCC Trial. CRLX101 clinical trial expenses increased by $2.0 million in 2014 compared to the prior year as a result of increased costs for our CRO and laboratories, as well as clinical site initiation costs and patient fees for the RCC Trial. Salary, benefits and other expenses allocated to CRLX101 increased $0.6 million in 2014 compared to the prior year to support CRLX101 development and clinical trials.

For the year ended December 31, 2014, costs associated with the CRLX301 program were $2.4 million compared to $2.3 million for the year ended December 31, 2013, an increase of $0.1 million, or 6%. The increase in CRLX301 program expense was primarily due to costs associated with the Phase 1/2a clinical trial that we initiated in December 2014. CRLX301 clinical trial expenses increased by $0.3 million in 2014 compared to the prior year. The increase was due to CRO and laboratory costs associated with initiating our Phase 1/2a clinical trial of CRLX301 including costs associated with setting up clinical sites and laboratories. Salary and benefits expenses allocated to CRLX301 increased $0.4 million in 2014 compared to the prior year. The increased CRLX301 expenses were partially offset by a $0.3 million decrease in research costs and a $0.3 million decrease in chemistry manufacturing and controls development activities as CRLX301 transitioned into clinical stage development.

Expenses associated with our Dynamic Tumor Targeting Platform decreased $0.8 million in 2014 as compared to 2013, mainly as a result of reduced staff in new discovery research as we continue to shift our emphasis to the development of our existing product candidates.

General and administrative. General and administrative expense for the year ended December 31, 2014, was $8.6 million compared to $6.2 million for the year ended December 31, 2013, an increase of $2.4 million, or 39%. The increase was primarily attributable to the incremental costs of being a public company, including an increase of $1.1 million for board of director fees, insurance for directors and officers, audit and tax fees, and corporate communication and printer fees. Salary and benefits expense increased $0.4 million in 2014 compared to the prior year reflecting additional resources in finance and accounting, legal and corporate communications, along with an increase in stock-based compensation expense. Professional and recruiting fees increased by $0.5 million in 2014 compared to 2013, primarily reflecting increased recruiting and placement fees. Other consulting costs also increased $0.4 million year over year. These increases in general and administrative costs were partially offset by a decrease in legal fees of $0.4 million.

Other expense, net. Other expense, net for the year ended December 31, 2014, was $3.1 million compared to $1.3 million for the year ended December 31, 2013, an increase of $1.8 million. The increase in net other expense primarily resulted from a loss of $2.5 million incurred on the conversion of convertible debt to common stock. The increase was offset by a decrease of $0.3 million due to a decrease in the value of the preferred stock warrant liability and a decrease in interest expense of $0.4 million.

From our incorporation through December 31, 2015, we raised an aggregate of $230.6 million to fund our operations, of which $84.2 million was from the sale of preferred stock in private placements, $59.9 million was from the IPO, $37.2 million was from the Secondary Offering, $17.3 million was from the sale of convertible promissory notes, $31.0 million was from borrowings under loan and security agreements and $1.0 million was from the private placement of our common stock to Hercules. As of December 31, 2015, we had cash and cash equivalents of approximately $75.9 million.

On January 8, 2015, we entered into the Hercules Loan Agreement and borrowed $15.0 million from Hercules. We used a portion of those proceeds to repay our outstanding indebtedness under the Lighthouse Loan Agreement.

The Hercules Loan Agreement provided for up to three separate tranches of borrowings, the first of which was funded in the amount of $15.0 million on January 8, 2015. On November 24, 2015, we drew a second tranche in the amount of $6.0 million. We elected not to commence a randomized Phase 2 clinical trial of CRLX101 in combination with chemoradiotherapy on or prior to December 15, 2015, which was a condition of obtaining an additional tranche in an amount of up to $5.0 million. As a result, we are no longer eligible to borrow this amount under the Hercules Loan Agreement.

Our indebtedness under the Hercules Loan Agreement will mature on July 1, 2018. Each advance under the Hercules Loan Agreement accrues interest at a floating per annum rate equal to the greater of (i) 7.30% or (ii) the sum of 7.30% plus the prime rate minus 5.75%. The Hercules Loan Agreement provided for interest-only payments on a monthly basis until December 31, 2015. Thereafter, payments are payable monthly in equal installments of principal and interest to fully amortize the outstanding principal over the remaining term of the loan, subject to recalculation upon a change in the prime rate. We may prepay the indebtedness under the Hercules Loan Agreement in whole or in part upon seven business days’ prior written notice to Hercules. Any such prepayment is subject to a prepayment charge of 2.0% if such prepayment occurs after January 8, 2016, but on or before January 8, 2017, or 1.0% if such prepayment occurs after January 8, 2017. Amounts outstanding during an event of default are payable upon Hercules’ demand and shall accrue interest at an additional rate of 5.0% per annum of the past due amount outstanding. At the end of the loan term (whether at maturity, by prepayment in full or otherwise), we shall pay a final end of term charge to Hercules in the amount of 6.7% of the aggregate original principal amount advanced by Hercules.

The Hercules Loan Agreement is secured by substantially all of our assets other than our intellectual property. We have also granted Hercules a negative pledge with respect to our intellectual property, which, among other things, prohibits us from selling, transferring, assigning, mortgaging, pledging, leasing, granting a security interest in or otherwise encumbering our intellectual property. The Hercules Loan Agreement includes restrictive covenants that may restrict our ability to obtain further debt or equity financing.

Lighthouse Loan Agreement. In 2011, we entered into the Lighthouse Loan Agreement which permitted us to borrow up to an aggregate principal amount of $10.0 million. We borrowed $5.0 million in March 2012 and an additional $5.0 million in August 2012. Interest accrued under the Lighthouse Loan Agreement at an annual rate of 8.25%. We repaid in full our outstanding indebtedness under the Lighthouse Loan Agreement and terminated the agreement on January 8, 2015. There were no prepayment charges associated with the early repayment of the loan.

Convertible Notes. In 2014, we issued and sold the 2014 Convertible Notes in an aggregate principal amount of $8.5 million, to certain of our stockholders and one additional purchaser. The 2014 Convertible Notes accrued interest at an annual rate of 7.0%. In connection with the completion of our IPO, all principal and accrued interest under our 2014 convertible notes converted into an aggregate of 1,582,931 shares of our common stock, at 77.5% of the IPO price, or $5.43 per share.

Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, clinical trial costs, contract manufacturing services, third-party clinical research and development services, laboratory and related supplies, legal and other regulatory expenses and general overhead costs.

We believe that our cash and cash equivalents as of December 31, 2015, will enable us to fund our operating expenses, debt service and capital expenditure requirements for at least 12 months from our 2015 financial statement issue date. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. Our future capital requirements will depend on many factors, including:

Identifying potential NDCs and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain regulatory approval and achieve product sales. In addition, our NDCs, if approved, may not achieve commercial success. Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings and revenue from collaboration arrangements. To the extent that we raise additional capital through the future sale of equity or debt, the ownership interest of our stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our existing common stockholders. If we raise additional funds through collaboration arrangements in the future, we may have to relinquish valuable rights to our technologies, future revenue streams or drug candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market drug candidates that we would otherwise prefer to develop and market ourselves.

The following table sets forth the primary sources and uses of cash for each period set forth below (in thousands):

The net use of cash in all periods resulted primarily from our net losses adjusted for non-cash charges and changes in components of working capital.

Net cash used in operating activities was $31.9 million for the year ended December 31, 2015, compared with $19.1 million for the year ended December 31, 2014, an increase of $12.8 million. The increase in net cash used in operating activities resulted primarily from an increase in operating expenses of $16.8 million and an increase in cash paid for interest of $0.6 million partially offset by an increase in stock compensation expense of $1.5 million and a change in components of working capital of $3.1 million.

Net cash used in operating activities was $19.1 million for the year ended December 31, 2014, compared with $16.6 million for the year ended December 31, 2013, an increase of $2.5 million. The increase in cash used in operating activities resulted from an increase in operating expenses of $4.5 million, partially offset by changes in the components of working capital of $1.7 million and a decrease in interest payments on our debt facility with Lighthouse Capital of $0.3 million.

Net cash used in investing activities was $0.5 million for the year ended December 31, 2015, compared to net cash used in investing activities of $0.2 million for the year ended December 31, 2014. For the year ended December 31, 2015, cash used in investing activities included $0.2 million increase in restricted cash to collateralize a stand-by letter of credit issued as a security deposit on a new facility lease. Cash used in investing activities for the purchase of lab equipment and computer equipment increased $52,000 to $277,000 for the year ended December 31, 2015, compared to $225,000 for the year ended December 31, 2014. Cash used in investing activities for the years ended December 31, 2015 and 2014, included proceeds for the sale of property and equipment of $23,000 and $40,000, respectively.

Net cash used in investing activities reflects purchases of property and equipment of $225,000 for the year ended December 31, 2014 compared to $7,000 for the year ended December 31, 2013, an increase of $218,000. The increase was attributable to purchases of laboratory, office and computer equipment of $173,000 and furniture, fixtures and leasehold improvements of $52,000 in the year ended December 31, 2014, compared to laboratory equipment purchases of $7,000 in the year ended December 31, 2013. The increase for the year ended December 31, 2014 was partially offset by proceeds of $40,000 from the sale of property and equipment.

Net cash provided by financing activities was $57.1 million for the year ended December 31, 2015, compared with $64.9 million for the year ended December 31, 2014. Net cash provided by financing activities for the year ended December 31, 2015, was primarily due to net proceeds of $37.2 million from our Secondary Offering, proceeds of $21.0 million from our borrowings under the Hercules Loan Agreement, proceeds of $1.0 million from the sale of our common stock in a private placement to Hercules and proceeds of $1.6 million from the exercise of stock options. Net cash provided by financing activities for the year ended December 31, 2015, was reduced by $3.3 million to repay in full amounts due under the Lighthouse Loan Agreement and cash paid for debt issuance costs of $0.4 million. For the year ended December 31, 2014, net cash provided by financing activities was primarily due to net proceeds of $59.9 million from our IPO and proceeds of $8.5 million from the sale of convertible promissory notes. Net cash provided by financing activities for the year ended December 31, 2014, was reduced by payments of $3.3 million under the Lighthouse Loan Agreement and cash paid for debt issuance costs of $0.2 million.

Net cash provided by financing activities was $64.9 million for the year ended December 31, 2014 compared with $5.4 million for the year ended December 31, 2013. For the year ended December 31, 2014, we raised net proceeds of $59.9 million from our IPO and $8.3 million through the sale of convertible promissory notes compared to raising $8.8 million through the sale of convertible promissory notes for the year ended December 31, 2013. We repaid indebtedness under the Loan Agreement with Lighthouse Capital in the amount of $3.3 million for the year ended December 31, 2014 compared to repayments of $3.1 million for the year ended December 31, 2013. We received $0.1 million of proceeds from the exercise of common stock options for the year ended December 31, 2014 compared to $35,000 for the year ended December 31, 2013.

The following summarizes our significant contractual obligations as of December 31, 2015 (in thousands):

Milestone and royalty payments associated with our license agreements have not been included in the above table of contractual obligations as we cannot reasonably estimate if or when they will occur. Possible future payments under our intellectual property agreements include the following:

The contractual obligations table does not include potential payments we may be required to make under manufacturing and CRO agreements as the timing of when these payments will actually be made is uncertain and the payments are contingent upon the initiation and completion of future activities.

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined under applicable SEC rules.

On February 25, 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2016-02, Leases, which provides new accounting guidance on leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018. We have not yet evaluated the impact of adoption of this new guidance.

In November 2015, the FASB, issued ASU 2015-17, Balance Sheet Classification of Deferred Taxes. To simplify the presentation of deferred taxes assets and liabilities, the new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. ASU 2015-17 is effective for public business entities in fiscal years beginning after December 15, 2016 and is not expected to have a material impact on our consolidated financial statements.

In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. To simplify presentation of debt issuance costs, ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for annual and interim reporting periods beginning January 1, 2016, and early adoption is permitted. We retrospectively adopted the guidance for our year ended December 31, 2015 and as a result, reclassified approximately $0.2 million in deferred financing costs that would have appeared as “Other assets” to “Long-term loan payable” in our accompanying consolidated balance sheet. The impact on prior years was not material.

We are exposed to market risk related to changes in interest rates. As of December 31, 2015, we had cash and cash equivalents, including restricted cash, of approximately $76.3 million, consisting primarily of investments in money market funds and certificates of deposit. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates, particularly because our investments are in cash and cash equivalents. Due to the short-term duration of our investment portfolio and the low risk profile of our investments, an immediate 10% change in interest rates would not have a material effect on the fair market value of our investment portfolio.

We have audited the accompanying consolidated balance sheets of Cerulean Pharma Inc. and subsidiary (the “Company”) as of December 31, 2015 and 2014, and the related consolidated statements of operations, redeemable convertible preferred stock and stockholders’ equity (deficit), and cash flows for each of the three years in the period ended December 31, 2015. 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. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, 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, such consolidated financial statements present fairly, in all material respects, the financial position of Cerulean Pharma Inc. and subsidiary as of December 31, 2015 and 2014, and the results of their operations and their cash flows for each of the three years in the period ended December 31, 2015, in conformity with accounting principles generally accepted in the United States of America.

	December 31,
	2015			2014
ASSETS
Current assets:
Cash and cash equivalents	$	75,908		$	51,174
Accounts receivable, prepaid expenses, and other current assets		1,394			1,662
Total current assets		77,302			52,836
Property and equipment, net		576			342
Other assets		347			215
Total	$	78,225		$	53,393
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Current portion of loan payable	$	7,652		$	3,124
Accounts payable		2,226			1,255
Accrued expenses		6,459			3,648
Other liabilities		—			34
Total current liabilities		16,337			8,061
Long-term liabilities:
Loan payable, net of current portion		12,672			—
Other long-term liabilities		473			7
Total long-term liabilities		13,145			7
Commitments (Note 12)
Stockholders’ equity:
Preferred stock, $0.01 par value; 5,000,000 shares authorized, no shares issued or outstanding		—			—
Common stock, $0.0001 par value; 120,000,000 shares authorized, 27,346,780 and 20,125,049 shares issued and outstanding at December 31, 2015 and 2014, respectively		3			2
Additional paid-in capital		210,115			167,104
Accumulated deficit		(161,375	)		(121,781	)
Total stockholders’ equity		48,743			45,325
Total	$	78,225		$	53,393

CONSOLIDATED STATEMENTS OF OPERATIONS (In thousands, except per share and share data)

	Years Ended December 31,
	2015			2014			2013
Revenue	$	—		$	80		$	6
Operating expenses:
Research and development		25,948			11,772			9,700
General and administrative		11,224			8,587			6,166
Total operating expenses		37,172			20,359			15,866
Other income (expense):
Interest income		10			9			2
Interest expense		(2,432	)		(1,083	)		(1,487	)
Loss on extinguishment of debt		—			(2,493	)		—
Decrease in value of preferred stock warrant liability		—			504			202
Total other income (expense), net		(2,422	)		(3,063	)		(1,283	)
Net loss attributable to common stockholders	$	(39,594	)	$	(23,342	)	$	(17,143	)
Net loss per share attributable to common stockholders:
Basic and diluted	$	(1.56	)	$	(1.60	)	$	(25.05	)
Weighted-average common shares outstanding:
Basic and diluted		25,431,332			14,548,516			684,330

	Redeemable Convertible Preferred Stock $0.01 Par Value						Common Stock $0.0001 Par Value				Additional Paid-In		Accumulated
	Shares			Amount			Shares		Amount		Capital		Deficit			Total
BALANCE — December 31, 2012		87,037,546		$	83,751		$	609,945	$	—	$	1,257	$	(81,296	)	$	(80,039	)
Exercise of stock options								8,911				35					35
Stock-based compensation												622					622
Conversion of preferred stock into common stock at $14.51 to $39.21 per share		(1,830,190	)		(2,226	)		166,675				2,226					2,226
Net loss														(17,143	)		(17,143	)
BALANCE — December 31, 2013		85,207,356			81,525			785,531		—		4,140		(98,439	)		(94,299	)
Exercise of stock options								41,566				140					140
Stock-based compensation												885					885
Issuance of common stock from initial public offering, net of underwriting fees and issuance costs of $7,126								9,569,715		1		59,861					59,862
Conversion of convertible preferred stock into common stock		(85,207,356	)		(81,525	)		6,826,004		1		81,525					81,526
Reclassification of warrants in connection with initial public offering												424					424
Conversion of convertible notes, net of issuance costs of $187								2,902,233				20,129					20,129
Net loss														(23,342	)		(23,342	)
BALANCE — December 31, 2014		—			—			20,125,049		2		167,104		(121,781	)		45,325
Exercise of stock options								370,230				1,628					1,628
Stock-based compensation												2,375					2,375
Issuance of common stock from public offering, net of underwriting fees and issuance costs of $3,111								6,716,000		1		37,184					37,185
Issuance of common stock from private placement								135,501				1,000					1,000
Issuance of warrants in connection with term loan facility								—				824					824
Net loss														(39,594	)		(39,594	)
BALANCE — December 31, 2015		—		$	—		$	27,346,780	$	3	$	210,115	$	(161,375	)	$	48,743

	Years Ended December 31,
	2015			2014			2013
Cash flows from operating activities:
Net loss	$	(39,594	)	$	(23,342	)	$	(17,143	)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation		2,375			885			622
Noncash rent expense		(41	)		29			(1	)
Change in carrying value of preferred stock warrant liability		—			(504	)		(202	)
Depreciation and amortization		192			126			197
(Gain) loss on disposal of property and equipment		(6	)		(28	)		7
Loss on extinguishment of debt		—			2,493			—
Amortization of debt discount and deferred financing costs		739			215			215
Changes in operating assets and liabilities:
Accounts receivable, prepaid expenses and other current assets		342			(695	)		(209	)
Accounts payable		795			341			14
Accrued expenses		3,283			1,419			(114	)
Net cash used in operating activities		(31,915	)		(19,061	)		(16,614	)
Cash flows from investing activities:
Purchases of property and equipment		(277	)		(225	)		(7	)
Proceeds from sale of property and equipment		23			40			—
Increase in restricted cash		(230	)		—			—
Net cash used in investing activities		(484	)		(185	)		(7	)
Cash flows from financing activities:
Proceeds from sale of common stock		2,628			140			35
Proceeds from public stock offering, net		37,185			59,862			—
Proceeds from loan payable		21,000			—			—
Proceeds from issuance of convertible promissory notes		—			8,500			8,824
Payments on loan payable		(3,321	)		(3,348	)		(3,084	)
Cash paid for debt issuance costs		(359	)		(222	)		(373	)
Net cash provided by financing activities		57,133			64,932			5,402
Net increase (decrease) in cash and cash equivalents		24,734			45,686			(11,219	)
Cash and cash equivalents — Beginning of year		51,174			5,488			16,707
Cash and cash equivalents — End of year	$	75,908		$	51,174		$	5,488
Supplemental disclosures of noncash investing and financing activities:
Purchase of property and equipment in accounts payable	$	177		$	—		$	—
Conversion of redeemable convertible preferred stock into common stock	$	—		$	81,526		$	2,226
Conversion of convertible notes and accrued interest into common stock, net	$	—		$	20,129		$	—
Reclassification of warrants to additional paid-in capital	$	—		$	424		$	—
Warrants issued with term loan facility	$	824		$	—		$	—
Supplemental cash flow information — Interest paid	$	1,000		$	400		$	664

Nature of Business — Cerulean Pharma Inc. (the “Company”) was incorporated on November 28, 2005, as a Delaware corporation and is located in Waltham, Massachusetts. The Company was formed to develop novel, nanotechnology-based therapeutics in the areas of oncology and other diseases. In 2013, the Company formed a wholly-owned subsidiary, Cerulean Pharma Australia Pty Ltd as an Australian-based proprietary limited company to perform clinical activities in Australia.

The Company's operations to date have consisted primarily of raising capital, product research and development, and initial market development.

The Company has not generated any revenue related to its primary business purpose to date and is subject to a number of risks similar to those of other development stage life science companies, including dependence on key individuals, competition from other companies, the need for development of commercially viable products, and the need to obtain adequate additional financing to fund the development of its product candidates. The Company is also subject to a number of risks similar to other companies in the industry, including rapid technological change, regulatory approval of products, uncertainty of market acceptance of products, competition from substitute products and larger companies, the need to obtain additional financing, compliance with government regulations, protection of proprietary technology, dependence on third parties, product liability and dependence on key individuals.

The Company has an accumulated deficit of $161.4 million at December 31, 2015. The Company has financed its operations primarily through private placements of its preferred stock, proceeds from borrowings, an initial public offering completed in 2014 and a follow-on offering completed in 2015. The Company has not completed development of any product candidate and has devoted substantially all of its financial resources and efforts to research and development, including preclinical and clinical development. Accordingly, the Company will continue to depend on its ability to raise capital through equity and debt issuances and/or through strategic partnerships. The Company expects to continue to incur significant expenses and increasing operating losses for at least several years. The Company believes that its cash and cash equivalents as of December 31, 2015, will be able to fund operating expenses, debt service and capital expenditure requirements for at least twelve months from our 2015 financial statement issuance date.

Follow-on Offering — On April 10, 2015, the Company completed the issuance and sale of 6,716,000 shares of common stock in an underwritten public offering at a price to the public of $6.00 per share. The sale of shares of common stock included 876,000 shares sold pursuant to the full exercise of the underwriters’ option to purchase additional shares of common stock. The net proceeds to the Company from this offering were $37.2 million after deducting underwriting discounts and commissions and offering expenses payable by the Company.

Initial Public Offering — On April 15, 2014, the Company completed the sale of 8,500,000 shares of its common stock in its initial public offering (the “IPO”), at a price to the public of $7.00 per share. On May 7, 2014, the Company completed the sale of an additional 1,069,715 shares of common stock at a price to the public of $7.00 per share under a partial exercise by the underwriters of their option to purchase additional shares of common stock. The sale of shares to the public resulted in net proceeds of $59.9 million after deducting underwriting discounts and commissions and offering expenses payable by the Company.

In connection with the closing of the IPO, all of the Company’s outstanding redeemable convertible preferred stock and convertible notes automatically converted into shares of common stock as of April 15, 2014, resulting in the issuance by the Company of an additional 9,728,237 shares of common stock.

In connection with the completion of the IPO on April 15, 2014, the Company’s outstanding warrants to purchase 1,857,226 shares of the Company’s preferred stock automatically converted into warrants to purchase an aggregate of 128,663 shares of the Company’s common stock and, as a result, the Company reclassified the warrant liability to additional paid-in capital.

Use of Estimates — The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period.

On an ongoing basis, the Company's management evaluates its estimates, including estimates related to clinical trial accruals, stock-based compensation expense, and reported amounts of revenues and expenses during the reported period. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Although the Company regularly assesses these estimates, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known.

Principles of Consolidation — The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany accounts and transactions have been eliminated.

Segment Information — Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment; however, the Company operates in two geographic regions: United States (Waltham, MA) and Australia (Sydney, NSW). There is no revenue generated or long-lived assets located within the Australian location.

Cash and Cash Equivalents — Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase and consist primarily of money market funds.

Concentrations of Credit Risk — Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. Substantially all of the Company’s cash and cash equivalents are held at one financial institution that management believes to be of high-credit quality. Deposits with this financial institution may exceed the amount of insurance provided on such deposits; however these deposits may be redeemed upon demand and, therefore, bear minimal risk.

Restricted Cash — At December 31, 2015 and 2014, the Company had restricted cash of $347,000 and $117,000, respectively. The restricted cash balances were used to collateralize stand-by letters of credit issued by the Company as a security deposit for its current and former facility leases. The balance at December 31, 2014, was with respect to the Company’s former facility lease that was scheduled to expire in February 2016 and was terminated early on December 31, 2015. The balance at December 31, 2015, includes the balance for the former facility lease and the Company’s new facility lease which is scheduled to expire in February 2021. The restricted cash is included within other assets in the balance sheet.

Property and Equipment — Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Repairs and maintenance costs are expensed as incurred, whereas major improvements are capitalized as additions to property and equipment.

Depreciation is provided using the straight-line method over the following estimated useful lives:

Impairment of Long-Lived Assets — Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. When such events occur, the Company compares the carrying amounts of the assets to their undiscounted expected future cash flows. If this comparison indicates that there is impairment, the amount of impairment is calculated as the difference between the carrying value and fair value. For the years ended December 31, 2015 and 2014, the Company has not recorded an impairment charge for its long-lived assets.

Revenue Recognition — The Company’s revenue to date has been insignificant and has been generated from short-term research agreements with pharmaceutical companies and federal grants. There have been no multiple element arrangements. Revenue is recognized when four basic criteria are met: (1) persuasive evidence of an arrangement exists, (2) delivery has occurred or services have been rendered, (3) the fee is fixed or determinable, and (4) collectability is reasonably assured. Accordingly, the Company has recognized revenue under its agreements as the services were performed.

Comprehensive Loss — Comprehensive loss consists of net loss and changes in equity during a period from transactions and other equity and circumstances generated from non-owner sources. The Company had no items of comprehensive loss, other than its net loss, for each of the periods presented.

Research and Development Costs — Research and development expenses consist of expenses incurred in performing research and development activities, including compensation and benefits for full-time research and development employees, an allocation of facilities expenses, overhead expenses, manufacturing process-development and scale-up activities, clinical trial and related clinical manufacturing expenses, fees paid to clinical research organizations, or CROs, and investigative sites, payments to universities under the Company’s license agreements and other outside expenses. In the early phases of development, the Company’s research and development costs are often devoted to expanding its product platform and are not necessarily allocable to a specific target. Research and development costs are expensed as incurred. Nonrefundable advanced payments, if any, for goods and services used in research and development are recognized as an expense as the related goods are delivered or services are performed.

Preferred Stock Warrant Liability — Freestanding warrants related to shares that are redeemable or contingently redeemable are classified as a liability on the Company’s balance sheets. The Company uses the Black-Scholes option-pricing model to estimate the fair value of the warrants. Changes in the fair value of these warrants are recorded in the statements of operations. All of the Company’s warrants to purchase preferred stock were converted to warrants to purchase common stock upon the Company’s IPO in April 2014. Accordingly, the preferred stock warrant liability was reclassified to additional paid-in capital.

Redeemable Convertible Preferred Stock — The Company classified redeemable convertible preferred stock that was redeemable outside of the Company’s control outside of permanent equity. The Company recorded such redeemable preferred stock at fair value upon issuance, net of any issuance costs or discounts, and the carrying value was being increased by periodic accretion to its redemption value. In the absence of retained earnings these accretion charges were recorded against additional paid-in capital, if any, and then to accumulated deficit. The Company amortized the accretion using the interest method. All of the Company’s redeemable convertible preferred stock was automatically converted to common stock in connection with the IPO.

Stock-Based Compensation — The Company accounts for stock-based awards at fair value, which is measured using the Black-Scholes option-pricing model. The fair value measurement date for employee awards is generally the date of grant. The fair value measurement date for nonemployee awards is generally the date the performance of services is completed. Stock-based compensation costs are recognized as an expense over the requisite service period, which is generally the vesting period, on a straight-line basis for all time-vested awards. The Company issued performance based grants where the vesting of the grant is tied to certain milestone performance and in these cases, the compensation is recognized as expense when the probability of the milestone is met.

Stock-based awards to nonemployees are remeasured at each reporting date and recognized as services are rendered, generally on a straight-line basis. The Company believes that the fair value of these awards is more reliably measurable than the fair value of the services rendered. Stock-based compensation is classified in the accompanying consolidated statements of operations in the department where the related services are provided.

Net Loss per Share Attributable to Common Stockholders — Basic net loss attributable to common stockholders per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. During periods where the Company might earn net income, the Company would allocate participating securities a proportional share of net income determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods where the Company incurred net loss, the Company allocates no loss to participating securities because they have no contractual obligation to share in the losses of the Company. The Company computes diluted loss per common share after giving consideration to the dilutive effect of stock options and warrants that are outstanding during the period, except where such nonparticipating securities would be antidilutive.

Income Taxes — Deferred income taxes are provided for the temporary differences arising between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes and for operating loss carryforwards and credits. Deferred tax assets and liabilities are recorded using tax rates expected to be in effect in the year in which the differences are expected to reverse. A valuation allowance is provided for any net deferred tax assets for which management believes it is more likely than not that the net deferred tax assets will not be realized.

The Company provides reserves for potential payment of tax to various tax authorities related to uncertain tax positions. The tax benefits recorded are based on a determination of whether and how much of a tax benefit taken by the Company in its filings or positions is “more likely than not” to be realized following resolution of any uncertainty related to the tax benefit, assuming the matter in question will be raised by the tax authorities. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of income tax expense. At December 31, 2015 and 2014, the Company has not identified any significant uncertain tax positions.

Guarantees and Indemnification — As permitted under Delaware law, the Company indemnifies its officers and directors employees for certain events or occurrences while the officer or director is, or was serving at the Company’s request in such a capacity. The term of the indemnification is for the officer’s or director’s lifetime.

Recent Accounting Pronouncements — On February 25, 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update 2016-02, “Leases” (“ASU 2016-02”), which provides new accounting guidance on leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018. The Company has not yet evaluated the impact of adoption of this new guidance.

In November 2015, the FASB issued Accounting Standards Update 2015-17, “Balance Sheet Classification of Deferred Taxes” (“ASU 2015-17”). To simplify the presentation of deferred taxes assets and liabilities, the new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. ASU 2015-17 is effective for public business entities in fiscal years beginning after December 15, 2016 and is not expected to have a material impact on the Company’s consolidated financial statements.

In April 2015, the FASB issued Accounting Standards Update 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”). To simplify presentation of debt issuance costs, ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for annual and interim reporting periods beginning January 1, 2016, and early adoption is permitted. The Company retrospectively adopted the guidance for its year ended December 31, 2015 and as a result, reclassified approximately $0.2 million in deferred financing costs that would have appeared as “Other assets” to “Long-term loan payable” in its accompanying consolidated balance sheet. The impact to prior years was not material.

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share data and per share data):

The Company has reported a net loss for all periods presented, therefore diluted net loss per common share is the same as basic net loss per common share.

The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted-average shares outstanding, because such securities had an antidilutive impact due to the losses reported (in common stock equivalent shares):

Depreciation and amortization expense for the years ended December 31, 2015, 2014, and 2013 was $192,000, $126,000, and $197,000, respectively.

In May 2010 and September 2010, the Company issued one-year convertible notes payable in the amounts of $5,000,000 and $1,500,000, respectively, to existing investors, with a stated interest rate of 7%. In November 2010, the principal and accrued interest of $176,000 were converted into 9,021,175 shares of Series C Preferred Stock at $0.74 per share. The Company also provided for the issuance of seven-year warrants to purchase Series C Preferred Stock with the notes. The issuance of the warrants was contingent upon the conversion of the notes to Series C Preferred Stock. The number of shares included in the warrants was determined by dividing 10% of the note principal converted to Series C Preferred Stock by the Series C Preferred Stock per share issue price. Concurrent with the conversion of the notes, warrants to purchase 878,370 shares of Series C Preferred Stock at $0.74 per share became exercisable. The Company estimated the fair value of the warrants on the issue date to be $474,000 using the Black-Scholes option-pricing model with the following assumptions: volatility of 80%, contractual term of seven years, risk-free interest rate of 1.85%, and no dividend yield. The Company determined the fair value of the warrants at the end of each subsequent reporting period using the Black-Scholes option-pricing model (see Note 10) until their conversion to warrants to purchase 60,532 shares of common stock upon the IPO in April 2014.

In August 2013, the Company issued convertible promissory notes in the amount of $8,824,000 to existing investors, with a stated interest rate of 7%. Outstanding principal and unpaid accrued interest due under the notes were automatically converted into shares of the Company’s common stock upon the closing of the Company’s IPO in April 2014.

In February and March 2014, the Company issued convertible promissory notes in the aggregate amount of $6,000,000 to existing investors and a convertible promissory note in the amount of $2,500,000 to a new investor. All the notes had a stated interest rate of 7%. Outstanding principal and unpaid accrued interest due under the notes were automatically converted into shares of the Company’s common stock upon the closing of the Company’s IPO in April 2014, at a conversion price equal to 77.5% of the IPO price. The Company recorded a loss on the extinguishment of the notes of $2,493,000 in April 2014, equal to the difference between the fair value of the shares into which the notes converted and the carrying amount of the notes upon the closing of the Company’s IPO.

On January 8, 2015 (the “Closing Date”), the Company entered into a term loan facility of up to $26.0 million (the “Term Loan”) with Hercules Technology Growth Capital, Inc. (“Hercules”). The proceeds were used to repay the Company’s existing term loan facility with Lighthouse Capital Partners VI, L.P. (“Lighthouse Capital”) and for general corporate and working capital purposes. At December 31, 2015, the Company had $21.0 million in principal outstanding under the Term Loan.

The Term Loan is governed by a loan and security agreement, dated January 8, 2015, between the Company and Hercules (the “Hercules Loan Agreement”). The Hercules Loan Agreement provided for up to three separate borrowings, the first of which was funded in the amount of $15.0 million on the Closing Date. On November 24, 2015, the Company drew a second tranche in the amount of $6.0 million. The Company elected not to commence a randomized Phase 2 clinical study of CRLX101 in combination with chemoradiotherapy on or prior to December 15, 2015, which was a condition of obtaining an additional tranche in an amount of up to $5.0 million. As a result, the Company is no longer eligible to borrow this amount under the Term Loan.

The Term Loan will mature on July 1, 2018. Each advance under the Term Loan accrues interest at a floating per annum rate equal to the greater of (i) 7.30% or (ii) the sum of 7.30% plus the prime rate minus 5.75%. The Term Loan provided for interest-only payments on a monthly basis until December 31, 2015. Thereafter, payments will be payable monthly in equal installments of principal and interest to fully amortize the outstanding principal over the remaining term of the loan, subject to recalculation upon a change in the prime rate. The Company may prepay the Term Loan in whole or in part upon seven business days’ prior written notice to Hercules. Any such prepayment of the Term Loan is subject to a prepayment charge of 2.0% if such prepayment occurs after twelve months following the Closing Date but on or prior to twenty-four months following the Closing Date and 1.0% thereafter. Amounts outstanding during an event of default are payable upon Hercules’ demand and shall accrue interest at an additional rate of 5.0% per annum of the past due amount outstanding. The minimum future principal payments are as follows (in thousands):

At the end of the loan term (whether at maturity, by prepayment in full or otherwise), the Company shall pay a final end of term charge to Hercules in the amount of 6.7% of the aggregate original principal amount advanced by Hercules. The amount of the end of term charge is being accrued over the loan term as interest expense.

In connection with the Hercules Loan Agreement, the Company issued to Hercules a warrant to purchase shares of the common stock of the Company at an exercise price of $6.05 per share. The warrant is exercisable for 171,901 shares of common stock. The warrant is exercisable until January 8, 2020. The Company estimated the fair value of the warrant for shares exercisable on the issue date in January 2015 to be $824,000. The value of the warrant was recorded as a discount to the loan. The fair value of the warrant was estimated on the date of issue for the exercisable shares at that date using the Black-Scholes option-pricing model. The following table shows the Black-Scholes assumptions used to value the warrant:

At December 31, 2015, the Company’s balance of unamortized deferred financing costs and unamortized debt discount were $0.2 million and $0.5 million, respectively. These costs are being amortized to interest expense using the effective interest method over the term of the loan.

In connection with the Hercules Loan Agreement, the Company entered into a stock purchase agreement with Hercules, whereby Hercules purchased 135,501 shares of common stock from the Company at a price per share of $7.38, which was equal to the closing price of the common stock on the NASDAQ Global Market on January 7, 2015, for an aggregate purchase price of approximately $1.0 million.

In December 2011, the Company entered into a loan and security agreement with Lighthouse Capital to borrow up to $10.0 million in one or more advances by December 31, 2012. In both March 2012 and August 2012, the Company borrowed $5.0 million under the loan and security agreement, for a total of $10.0 million. This amount was being repaid over 36 months beginning on December 1, 2012, at an interest rate of 8.25%. In addition, the Company was required to make an additional payment in the amount of $600,000 at the end of the loan term. The amount was accrued over the loan term as interest expense. The amount accrued as of December 31, 2014 was $574,000, and it was included in accrued expense in the Company’s consolidated balance sheet. In January 2015, the Company repaid in full the amount outstanding under the Lighthouse Capital agreement, or $3.6 million, with the proceeds from the Hercules Loan Agreement.

In connection with the loan and security agreement with Lighthouse Capital, the Company issued Lighthouse Capital a warrant to purchase a maximum of 66,436 shares of the Company’s Series D Preferred Stock, at an exercise price of $12.04 per share and with an expiration date 10 years from the date of issue (December 2021). The Company determined the fair value of the warrant at the end of each reporting period using the Black-Scholes option pricing model until the warrant converted to a warrant to purchase 66,436 shares of common stock upon the completion of the IPO. The value of the warrant was recorded as a discount to the loan and was being amortized as interest expense using the effective interest method over the 36-month repayment term. The unamortized discount relating to the warrants, or $0.2 million, was expensed as interest expense upon repayment of the loan in January 2015.

Common Stock — As discussed in Note 1, in April 2015, the Company issued 6,716,000 shares of common stock in connection with an underwritten public offering and during 2014 the Company issued 19,297,952 shares of common stock in connection with its IPO, the conversion of preferred stock and convertible notes into common stock, and the partial exercise of the underwriters’ overallotment option in the IPO.

Reserved Shares of Common Stock — The Company has reserved the following number of shares of common stock at December 31, 2015 and 2014:

2007 Stock Incentive Plan – The Company’s 2007 Incentive Stock Plan, or the 2007 Plan, provides for the grant of qualified incentive stock options and nonqualified stock options or other awards to the Company’s employees, officers, directors, advisors, and outside consultants to purchase up to an aggregate of 1,275,211 shares of the Company’s common stock, as amended in January 2014. The stock options generally vest over a four-year period and expire 10 years from the date of grant. Certain options provide for accelerated vesting if there is a change in control, as defined in the 2007 Plan. Effective with the IPO, no additional grants will be issued from the 2007 Plan and all shares available for grant under the 2007 Plan were transferred to the 2014 Plan. Accordingly, at December 31, 2015 and 2014, there were no shares available for future grant under the 2007 Plan.

Prior to the IPO, in determining the exercise prices for options granted, the Company’s board of directors considered the fair value of the common stock as of the measurement date. The fair value of the common stock was determined by the board of directors at each award grant date based upon a variety of factors, including the results obtained from a common stock valuation, the Company’s financial position and historical financial performance, the status of technological developments within the Company’s products, the composition and ability of the current research and management team, an evaluation or benchmark of the Company’s competition, the current business climate in the marketplace, the illiquid nature of the common stock, arm’s-length sales of the Company’s capital stock (including redeemable convertible preferred stock), the effect of the rights and preferences of the preferred shareholders, and the prospects of a liquidity event, among others.

2014 Stock Incentive Plan – In March 2014, the Company’s board of directors adopted and its stockholders approved the 2014 Stock Incentive Plan, or the 2014 Plan, which became effective upon the closing of the IPO. The 2014 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards. The 2014 Plan provides an annual increase in the number of shares available for grant on the first day of each calendar year beginning with the fiscal year ended December 31, 2015 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2024, equal to the lesser of (i) 1,000,000 shares of common stock, (ii) 4% of the number of outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. As of December 31, 2015, there were 540,950 shares available for future grant under the 2014 Plan.

A summary of stock option activity for employee and nonemployee awards under the 2007 Plan and the 2014 Plan during the year ended December 31, 2015 is presented below (Aggregate Intrinsic Value in thousands):

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding — January 1, 2015		2,126,176		$	4.97		6.7	$	2,701
Granted		2,360,682			5.66
Exercised		(370,230	)		4.40
Forfeited		(661,702	)		5.86
Outstanding — December 31, 2015		3,454,926		$	5.39		8.9	$	—
Options expected to vest — December 31, 2015		2,336,878		$	5.32		9.4	$	—
Options exercisable — December 31, 2015		1,001,415		$	5.56		7.7	$	—

The total intrinsic value of stock options exercised in the years ended December 31, 2015, 2014, and 2013 was $0, $161,000, and $15,000, respectively.

The weighted-average per share grant date fair value of options granted during 2015, 2014, and 2013 was $3.22, $3.33, and $2.90, respectively.

The Company has recorded stock-based compensation expense of $2.4 million, $885,000, and $622,000 during the years ended December 31, 2015, 2014, and 2013, respectively, which is based on the number of awards ultimately expected to vest. As of December 31, 2015, there was $6.1 million of unrecognized compensation cost related to unvested stock-based compensation arrangements granted under the 2007 Plan and the 2014 Plan. The compensation is expected to be recognized over a weighted-average period of 2.88 years at December 31, 2015.

Stock-based compensation expense recorded as research and development and general and administrative expenses is as follows (in thousands):

The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model based on the assumptions noted in the table below. Expected volatility for the Company’s common stock was determined based on an average of the historical volatility of a peer-group of similar public companies. The Company has limited option exercise information, as such, the expected term of the options granted was calculated using the simplified method that represents the average of the contractual term of the option and the weighted-average vesting period of the option. The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future. The risk-free rate for periods within the contractual life of the option is based upon the U.S. Treasury yield curve in effect at the time of grant.

The assumptions used in the Black-Scholes option-pricing model for stock options granted to employees during the years ended December 31, 2015, 2014, and 2013 are as follows:

The Company recorded stock-based compensation expense related to nonemployee awards of $173,000, $56,000, and $85,000 for the years ended December 31, 2015, 2014, and 2013, respectively. The compensation expense related to the nonemployee awards is included in the total stock-based compensation each year and is subject to re-measurement until the options vest. The Black-Scholes assumptions used to estimate the fair value of these awards for the years ended December 31, 2015, 2014, and 2013 were as follows:

During the year ended December 31, 2015, the Company granted nonemployee stock options to consultants for the purchase of 204,000 shares of the Company’s common stock. The weighted-average exercise price and the weighted-average fair value of nonemployee stock options granted for the year ended December 31, 2015, was $5.17 per share and $1.58 per share, respectively. The fair value of the grants is being expensed over the vesting period of the options on a straight-line basis as the services are being provided. On September 4, 2015, nonemployee stock options to purchase 90,000 shares of the Company’s common stock were converted to employee stock options upon the appointment of the Company’s Chief Medical Officer who had been serving as a consultant to the Company until his appointment. The exercise price and the fair value of these stock options is $4.71 per share and $2.71 per share, respectively. The Company did not grant any nonemployee stock option grants in 2014 or in 2013, except for a performance award grant in 2013 to the Company’s board chairman for non-board related services. During the year ended December 31, 2014, the board of directors changed the vesting conditions of this award from performance-based vesting to time-based vesting and reduced the total number of shares subject to the stock option. As a result, the 16,000 shares subject to this stock option now vest over three years, with the first third vesting on March 26, 2014. The change in vesting condition was accounted for as a modification of this stock option, which had an immaterial impact on the Company’s financial statements.

In 2012, the Company granted options to purchase 60,934 common shares to an officer of the Company, now the Company’s Chief Executive Officer, that will vest upon the achievement of business milestones as defined within the stock option agreement. These awards have not vested as of December 31, 2015. Compensation expense for the awards will be recorded if and when the awards are determined to be probable.

2014 Employee Stock Purchase Plan – In March 2014, the Company’s board of directors adopted and its stockholders approved the 2014 Employee Stock Purchase Plan (the “2014 ESPP”), which became effective upon the closing of the IPO. The 2014 ESPP will be administered by the Company’s board of directors or by a committee appointed by the Company’s board of directors. The 2014 ESPP initially provides participating employees with the opportunity to purchase up to an aggregate 500,000 of shares of the Company’s common stock. The number of shares of the Company’s common stock reserved for issuance under the 2014 ESPP will automatically increase on the first day of each fiscal year, commencing on January 1, 2015 and ending January 1, 2024, in an amount equal to the least of (i) 600,000 shares of the Company’s common stock, (ii) 1% of the total number of shares of the Company’s common stock outstanding on the first day of the applicable year, or (iii) an amount determined by the Company’s board of directors. There are two six-month offerings per year. The first offering period under the 2014 ESPP began on July 1, 2015. The compensation expense related to the 2014 ESPP is included in the total stock-based compensation. The stock-based compensation expense related to the ESPP for the year ended December 31, 2015, was $27,000. There was no stock-based compensation related to the 2014 ESPP recorded for the year ended December 31, 2014.

The Company’s financial instruments consist of cash equivalents, accounts payable, accrued expenses, debt obligations, and preferred stock warrants. The carrying amount of accounts payable and accrued expenses are considered a reasonable estimate of their fair value, due to the short-term maturity of these instruments. The carrying amount of debt is also considered to be a reasonable estimate of the fair value based on the short-term nature of the debt and that the debt bears interest at the prevailing market rate for instruments with similar characteristics. If recorded at fair value, Level 2 measurements, as defined below, would have been used to estimate the fair value. Included in cash and cash equivalents as of December 31, 2015 and 2014, are money market fund investments of $75,325,000 and $50,541,000, respectively, which are reported at fair value.

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value are performed in a manner to maximize the use of observable inputs and minimize the use of unobservable inputs.

The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, which are the following:

Level 1 — Quoted prices in active markets that are accessible at the market date for identical unrestricted assets or liabilities.

Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs for which all significant inputs are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

A summary of the financial assets and liabilities that are measured on a recurring basis at fair value as of December 31, 2015 and 2014, is as follows (in thousands):

The Company’s money market funds have been valued on the basis of valuations provided by third-party pricing services, as derived from such services’ pricing models. Inputs to the models may include, but are not limited to, reported trades, executable bid and asked prices, broker/dealer quotations, prices or yields of securities with similar characteristics, benchmark curves or information pertaining to the issuer, as well as industry and economic events. The pricing services may use a matrix approach, which considers information regarding securities with similar characteristics to determine the valuation for a security. The Company is ultimately responsible for the consolidated financial statements and underlying estimates. Accordingly, the Company assesses the reasonableness of the valuations provided by the third-party pricing services by reviewing actual trade data, broker/dealer quotes and other similar data, which are obtained from quoted market prices or other sources.

For the years ended December 31, 2015 and 2014, there have been no transfers between levels.

The reconciliation of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows:

The Company’s warrants were valued using the Black-Scholes option-pricing model. The fair values were derived by applying the following assumptions:

The preferred stock warrants were automatically adjusted on the date of the closing of the IPO to provide for the issuance of shares of common stock upon their exercise, and is no longer measured at fair value.

Significant components of the Company’s deferred taxes at December 31, 2014, and 2013 are as follows:

The Company has provided a valuation allowance for the full amount of deferred tax assets as the realization of the deferred tax assets is not determined to be more-likely-than-not. The valuation allowance increased in 2015 and 2014 by approximately $15.6 million and $7.6 million, respectively, due to the increase in the deferred tax assets by the same amount. The increases are mainly attributable to operating losses generated in the period.

A reconciliation of income tax expense computed at the statutory federal income tax rate to income taxes as reflected in the financial statements is as follows:

At December 31, 2015, the Company has approximately $93.7 million of federal and $74.1 million of state net operating loss carryforwards that expire at various dates through 2035. At December 31, 2015, the Company has approximately $1.4 million of federal and $0.9 million of state research and development credit carryforwards that expire at various dates through 2035 for federal credits and 2030 for state credits.

At December 31, 2014, the Company has approximately $77.3 million of federal and $58.1 million of state net operating loss carryforwards that expire at various dates through 2034. At December 31, 2014, the Company has approximately $1.2 million of federal and $0.8 million of state research and development credit carryforwards that expire at various dates through 2034 for federal credits and 2029 for state credits.

Realization of the future tax benefits is dependent on many factors, including the Company’s ability to generate taxable income within the net operating loss carryforward period. The future realization of the net operating loss carryforwards may also be limited by the change of ownership rules of the Internal Revenue Service under Section 382 of the Internal Revenue Code. If substantial changes in ownership should occur, there could be annual limitations on the amount of carryforwards that can be realized in future periods.

The Company files income tax returns in the United States, the Commonwealth of Massachusetts, and Australia. The tax years 2006 through 2014 remain open to examination by these taxing jurisdictions, as carryforwards attributes generated in past years may be adjusted in a future period. The Company is currently not under examination by the Internal Revenue Service or any other jurisdictions for any tax years. At December 31, 2015 and 2014, the Company has not identified any significant uncertain tax positions.

Facility Lease — On November 1, 2009, the Company entered into a noncancelable operating lease with a third party for office and laboratory space that was scheduled to expire in February 2013, subject to a three-year renewal option. In June 2012, the Company exercised its renewal option extending the lease through February 2016. On July 11, 2014, the Company signed a lease amendment for additional office space in the same building to expire concurrent with the lease agreement in February 2016. The Company terminated the lease agreement early in December 2015 without penalty. The lease agreement and amendment included base rent escalation over the lease term therefore, the Company amortized the cost of the lease on a straight-line basis over the lease term. The resulting deferred liability recorded in other current and long-term liabilities as of December 31, 2014 was $41,000. Rent expense under this lease was $920,000, $766,000, and $598,000 for the years ended December 31, 2015, 2014, and 2013, respectively.

On July 9, 2015, the Company entered into a noncancelable operating lease with a third party for office, laboratory and vivarium space that is scheduled to expire in February 2021, subject to a three-year renewal option. The lease agreement includes base rent escalation over the lease term which will be amortized on a straight-line basis over the lease term with the resulting deferred liability recorded in other current and long-term liabilities. The lease requires the Company to share in prorated expenses and property taxes based upon actual amounts incurred; those amounts are not fixed for future periods and, therefore, not included in the future minimum obligations listed below.

Future minimum lease payments under the non-cancelable operating lease are as follows (in thousands):

Calando License — The Company has a product license agreement and a platform license agreement with Calando Pharmaceuticals, Inc. (“Calando”). Under the product license agreement, the Company may be required to pay Calando up to $32.8 million upon the achievement of specified regulatory and commercial milestones and pay tiered royalty payment ranging from low-to mid-single digits on commercial sales.

Under the platform license agreement, the Company paid Calando a $250,000 clinical development milestone which was recorded in December 2014 upon initiation of the Phase 1/2a clinical trial for CRLX301. The Company may be required to make additional milestone payments to Calando of up to $17.8 million, in the aggregate, upon the achievement of specified regulatory and commercial milestones and pay royalty payments ranging from low-to mid-single digits on commercial sales.

In March 2014, Calando entered Chapter 7 bankruptcy in the District of Delaware and, as a result, the intellectual property rights the Company has obtained from Calando are subject to potential risks that may arise in connection with bankruptcy. For instance, while the Company’s ability to develop and/or commercialize its current product candidates and its ability to utilize its platform are not dependent on the rights that it licenses from Calando, its license agreements with Calando could be rejected in connection with Calando’s bankruptcy, in which case, the Company could, subject to elections and other rights and defenses that may be available to it, lose certain rights granted to it under such licenses. On March 3, 2015, Calando’s bankruptcy trustee submitted an application with the bankruptcy court seeking authority to retain a broker to sell Calando’s rights in certain assets including its rights in the license agreements with the Company, the Company has reserved its rights with respect to any such sale.

SUNY License — The Company is party to a license agreement with The Research Foundation of State University of New York (“SUNY”) for certain intellectual property. The agreement as amended requires the Company to pay nonrefundable annual license maintenance fees each year until the date of first commercial sale of a licensed product pursuant to the license agreement, as amended. The annual license fee is not material in any individual year. In the event of future partner collaborations or product sales incorporating technology covered by this license agreement, the Company may be required to pay milestone payments and/or product royalties. In connection with this agreement, the Company recorded research and development expense of $36,000, $30,000, and $25,000 for the years ended December 31, 2015, 2014, and 2013, respectively.

Massachusetts Institute of Technology License — The Company delivered a notice of termination which became effective on November 1, 2015, with respect to the Company’s license agreement with the Massachusetts Institute of Technology (“MIT”). The agreement as amended required the Company to pay MIT nonrefundable annual license maintenance fees that increased each year beginning in 2015. In connection with this agreement, the Company recorded research and development expense for annual maintenance fees of $50,000 for the year ended December 31, 2015, and $10,000 each in the years ended December 31, 2014 and 2013.

The Company has a 401(k) retirement and profit-sharing plan (the “401(k) Plan”) covering all qualified employees. The 401(k) Plan allows each participant to contribute a portion of their base wages up to an amount not to exceed an annual statutory maximum. Effective January 1, 2010, the Company adopted a Safe Harbor Plan that provides a Company match up to 4% of salary. The Company contributed a match of $264,000, $163,000, and $145,000 to the 401(k) Plan for the years ended December 31, 2015, 2014, and 2013, respectively.

In April 2013, the Company entered into a laboratory, equipment sharing, services and license agreement with an entity affiliated with one of the Company’s directors. Fees recorded offsetting research and development expenses under this agreement and paid in the year ended December 31, 2014 and 2013, were $39,000 and $84,000, respectively. On April 1, 2014, the Company sold used equipment to this entity and recorded proceeds from the sale of $30,000. The agreement was terminated on April 1, 2014.

In August 2013 and February 2014, the Company issued convertible promissory notes to existing investors, as described in Note 6. In April 2014, these notes were converted into the Company’s common stock in connection with the IPO.

In April 2014, the Company converted all outstanding shares of the Company’s preferred stock held by existing investors into 6,826,004 shares of the Company’s common stock in connection with the IPO.

In October 2013, the Company entered into a material transfer agreement with biopharmaceutical company to conduct feasibility studies using the Company’s proprietary technology. The Company recognized revenue of $61,000 and $6,000 for the years ended December 31, 2014 and 2013, respectively, in connection with this material transfer agreement. The Company had no revenue for the year ended December 31, 2015.

In May 2013, the Company entered into a material transfer agreement with another biopharmaceutical company to conduct feasibility studies using the Company’s proprietary technology. The Company recognized revenue of $19,000 for the year ended December 31, 2014, in connection with this material transfer agreement.

The following table summarizes the unaudited quarterly financial data for the last two fiscal years:

CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except share data and per share data)

	Year Ended December 31, 2015
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	—		$	—		$	—		$	—
Operating expenses:
Research and development		5,021			6,678			7,092			7,157
General and administrative		2,681			2,717			2,954			2,872
Total operating expenses		7,702			9,395			10,046			10,029
Other income (expense):
Interest income		3			1			4			2
Interest expense		(721	)		(513	)		(509	)		(689	)
Total other income (expense) — net		(718	)		(512	)		(505	)		(687	)
Net loss attributable to common stockholders	$	(8,420	)	$	(9,907	)	$	(10,551	)	$	(10,716	)
Net loss per share attributable to common stockholders:
Basic and diluted	$	(0.41	)	$	(0.37	)	$	(0.39	)	$	(0.39	)
Weighted-average common shares outstanding:
Basic and diluted		20,350,557			26,690,673			27,307,103			27,346,780

	Year Ended December 31, 2014
	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
Revenue	$	47		$	33		$	—		$	—
Operating expenses:
Research and development		1,495			2,648			2,928			4,701
General and administrative		1,510			2,029			2,441			2,607
Total operating expenses		3,005			4,677			5,369			7,308
Other income (expense):
Interest income		1			2			2			4
Interest expense		(461	)		(268	)		(191	)		(163	)
Loss on extinguishment of debt		—			(2,493	)		—			—
Decrease in value of preferred stock warrant liability		504			—			—			—
Total other income (expense) — net		44			(2,759	)		(189	)		(159	)
Net loss attributable to common stockholders	$	(2,914	)	$	(7,403	)	$	(5,558	)	$	(7,467	)
Net loss per share attributable to common stockholders:
Basic and diluted	$	(3.70	)	$	(0.44	)	$	(0.28	)	$	(0.37	)
Weighted-average common shares outstanding:
Basic and diluted		786,986			16,883,716			20,124,574			20,125,009

We have established disclosure controls and procedures designed to ensure that information required to be disclosed in the reports that we file or submit under the Securities Exchange Act of 1934, as amended, or the Exchange Act, is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms and is accumulated and communicated to management, including the principal executive officer and principal financial officer, to allow timely decisions regarding required disclosure.

Our management, under the supervision and with the participation of our principal executive officer and principal financial officer, has evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) as of the end of the period covered by this Annual Report on Form 10-K. Management recognizes that any disclosure controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives. Our disclosure controls and procedures have been designed to provide reasonable assurance of achieving their objectives. Based on such evaluation, our principal executive officer and principal financial officer concluded that our disclosure controls and procedures were effective at the reasonable assurance level as of December 31, 2015.

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rules 13a-15(f) and 15d-15(e) under the Exchange Act.

Under the supervision and with the participation of management, including our principal executive officer and principal financial officer, we conducted an assessment of the effectiveness of our internal control over financial reporting based on the criteria set forth in “Internal Control-Integrated Framework (2013)” issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on this assessment, management concluded that, as of December 31, 2015, our internal control over financial reporting was effective.

This annual report does not include an attestation report of our registered public accounting firm on internal control over financial reporting due to an exemption established by the JOBS Act for “emerging growth companies”.

There were no changes in our internal control over financial reporting identified in connection with the evaluation required by Rule 13a-15(d) and 15d-15(d) of the Exchange Act that occurred during the quarter ended December 31, 2015 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Christopher D. T. Guiffre, age 47, has served as our President and Chief Executive Officer since March 2015. He previously served as our Chief Operating Officer and Senior Vice President and Chief Business Officer. Prior to that, Mr. Guiffre held a number of senior executive positions at various biopharmaceutical companies, including President and Chief Executive Officer of Alvos Therapeutics, Inc., Chief Business Officer at Hydra Biosciences, Inc. and a senior executive at Cubist Pharmaceuticals, Inc., most recently as Senior Vice President, General Counsel and Secretary. Mr. Guiffre has also held several positions at Renaissance Worldwide, Inc., including Vice President, General Counsel and Clerk. Prior to that, he was an Associate at Bingham, Dana & Gould LLP (now known as Morgan, Lewis & Bockius LLP). Mr. Guiffre received a B.S. from Babson College, a J.D. from Boston College Law School, and an M.B.A. from Boston College Carroll School of Management.

Gregg D. Beloff, age 47, has served as our Interim Chief Financial Officer since May 2015. Mr. Beloff has been a Managing Director of Danforth Advisors, a consulting firm specializing in providing financial and strategic support to life sciences companies, since April 2011. In addition to consulting for clients, Mr. Beloff previously served as the chief financial officer of two public and three privately held companies. In these roles, he has managed finance, accounting, corporate communications, human resources, information technology, facilities, legal, intellectual property, business development, and manufacturing functions. Mr. Beloff holds a J.D. from the University of Pittsburgh School of Law, an M.B.A. from Carnegie Mellon University, and a B.A. in History from Middlebury College.

Adrian M. Senderowicz, M.D., age 52, has served as our Chief Medical Officer and Senior Vice President since September 2015. Prior to joining Cerulean, Dr. Senderowicz worked at Ignyta, Inc., a public precision oncology biotechnology company, as Chief Medical Officer and Senior Vice President, Clinical Development and Regulatory Affairs from August 2014 to February 2015, and as Clinical and Regulatory Strategy Officer from February 2015 to April 2015. Previously, he was Vice President, Global Regulatory Oncology at Sanofi, a biopharmaceutical company, from September 2013 to August 2014, and Chief Medical Officer at Tokai Pharmaceuticals, Inc., a biopharmaceutical company focused on prostate cancer treatment, from August 2012 to March 2013. From August 2008 to March 2012, Dr. Senderowicz held positions of increasing responsibility at AstraZeneca, a global biopharmaceutical company, including most recently as Senior Medical Director, Oncology Clinical Development. Before his tenure at AstraZeneca, Dr. Senderowicz held a variety of leadership positions at the U.S. Food and Drug Administration Division of Oncology Drug Products in the Center for Drug Evaluation and Research and a variety of clinical and research positions with the National Cancer Institute/National Institutes of Health (NCI), including Investigator and Chief, Molecular Therapeutics Unit. He currently serves as a director of Puma Biotechnology, Inc., a publicly traded biopharmaceutical company. He completed his Internal Medicine residency training at the Icahn School of Medicine at Mount Sinai, and a Clinical Oncology Fellowship at the NCI. Dr. Senderowicz holds an M.D. from the School of Medicine at the Universidad de Buenos Aires in Argentina.

Alejandra V. Carvajal, age 42, has served as our Vice President and General Counsel since September 2014. Prior to joining Cerulean, and beginning in 2004, Ms. Carvajal held a variety of positions at Millennium: The Takeda Oncology Company, or Millennium, including most recently as Associate General Counsel. Ms. Carvajal joined Millennium as a senior attorney and enjoyed over ten years of increasing responsibilities relating to all aspects of oncology drug development. Prior to joining Millennium, Ms. Carvajal was an attorney with the law firms Day, Berry & Howard, and Hill & Barlow. Ms. Carvajal received a B.A. cum laude from Harvard University and a J.D. cum laude from Georgetown University Law Center.

The remaining information required by this Item 10 will be contained in our proxy statement for our 2016 annual meeting of stockholders and is incorporated herein by reference.

The information required by this Item 11 will be contained in our proxy statement for our 2016 annual meeting of stockholders and is incorporated herein by reference.

The information required by this Item 12 will be contained in our proxy statement for our 2016 annual meeting of stockholders and is incorporated herein by reference.

The information required by this Item 13 will be contained in our proxy statement for our 2016 annual meeting of stockholders and is incorporated herein by reference.

The information required by this Item 14 will be contained in our proxy statement for our 2016 annual meeting of stockholders and is incorporated herein by reference.

Our consolidated financial statements are set forth in Part II, Item 8 of this Annual Report on Form 10-K and are incorporated herein by reference.

All financial schedules have been omitted because the required information is either presented in the consolidated financial statements or the notes thereto or is not applicable or required.

The exhibits required by Item 601 of Regulation S-K and Item 15(b) of this Annual Report on Form 10-K are listed in the Exhibit Index immediately preceding the exhibits and are incorporated herein.

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

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 and on the dates indicated.

/s/ Christopher D. T. Guiffre	President, Chief Executive Officer, and Director	March 10, 2016
Christopher D. T. Guiffre	(Principal Executive Officer)

/s/ Gregg D. Beloff	Interim Chief Financial Officer	March 10, 2016
Gregg D. Beloff	(Principal Financial Officer)

/s/ James E. O’Neill	Controller	March 10, 2016
James E. O’Neill	(Principal Accounting Officer)

/s/ Paul A. Friedman	Director	March 10, 2016
Paul A. Friedman, M.D.

/s/ William H. Rastetter	Director	March 10, 2016
William H. Rastetter, Ph.D.

/s/ Stuart A. Arbuckle	Director	March 10, 2016
Stuart A. Arbuckle

/s/ Alan L. Crane	Director	March 10, 2016
Alan L. Crane

/s/ Steven E. Hall	Director	March 10, 2016
Steven E. Hall, Ph.D.

/s/ Susan L. Kelley	Director	March 10, 2016
Susan L. Kelley, M.D.

/s/ William T. McKee	Director	March 10, 2016
William T. McKee

/s/ David R. Parkinson	Director	March 10, 2016
David R. Parkinson, M.D.

/s/ David R. Walt	Director	March 10, 2016
David R. Walt, Ph.D.

Incorporated By Reference

Exhibit Number

Description of Exhibit

Form

File Number

Date of Filing

Exhibit

Number

Filed

Herewith

3.1

Restated Certificate of Incorporation

8-K

001-36395

April 16, 2014

3.1

3.2

Amended and Restated By-Laws

8-K

001-36395

April 16, 2014

3.2

4.1

Specimen Stock Certificate evidencing the shares of common stock

S-1/A

333-194442

March 31, 2014

4.1

10.1#

2007 Stock Incentive Plan, as amended

S-1

333-194442

March 10, 2014

10.1

10.2#

Form of Incentive Stock Option Agreement under 2007 Stock Incentive Plan

S-1

333-194442

March 10, 2014

10.2

10.3#

Form of Nonstatutory Stock Option Agreement under 2007 Stock Incentive Plan

S-1

333-194442

March 10, 2014

10.3

10.4#

2014 Stock Incentive Plan

S-1

333-194442

March 31, 2014

10.4

10.5#

Form of Incentive Stock Option Agreement under 2014 Stock Incentive Plan

S-1

333-194442

March 31, 2014

10.5

10.6#

Form of Nonstatutory Stock Option Agreement under 2014 Stock Incentive Plan

S-1

333-194442

March 31, 2014

10.6

10.7#

2014 Employee Stock Purchase Plan

S-1

333-194442

March 31, 2014

10.26

10.8†

License Agreement, dated as of May 22, 2000, as amended, between California Institute of Technology and Insert Therapeutics, Inc.

S-1

333-194442

March 10, 2014

10.7

10.9†

Patent License Agreement, dated as of August 31, 2007, as amended, between the Registrant and The Research Foundation of State University of New York, on behalf of University of Buffalo

S-1

333-194442

March 10, 2014

10.9

10.10†

IT-101 Agreement, dated as of June 23, 2009, between the Registrant and Calando Pharmaceuticals, Inc.

S-1

333-194442

March 10, 2014

10.10

10.11†

Platform Agreement, dated as of June 23, 2009, between the Registrant and Calando Pharmaceuticals, Inc.

S-1

333-194442

March 10, 2014

10.11

10.12†

Letter Agreement, dated as of August 6, 2013, between the Registrant and California Institute of Technology

S-1

333-194442

March 10, 2014

10.12

10.13

Second Series D Convertible Preferred Stock Purchase Agreement, dated November 30, 2012, as amended

S-1

333-194442

March 10, 2014

10.13

10.14

Loan and Security Agreement, dated January 8, 2015, between the Registrant and Hercules Technology Growth Capital, Inc.

8-K

001-36395

January 8, 2015

10.1

10.15

Stock Purchase Agreement, dated January 8, 2015, between the Registrant and Hercules Technology Growth Capital, Inc.

8-K

001-36395

January 8, 2015

10.2

10.16

Right to Invest Letter, dated January 8, 2015, between the Registrant and Hercules Technology Growth Capital, Inc.

8-K

001-36395

January 8, 2015

10.3

10.17

Warrant, dated January 8, 2015, issued to Hercules Technology Growth Capital, Inc.

8-K

001-36395

January 8, 2015

4.1

10.18#

Form of Indemnification Agreement between the Registrant and each of its Executive Officers and Directors

S-1

333-194442

March 10, 2014

10.16

10.19

Warrant to purchase shares of Series B Convertible Preferred Stock issued by the Registrant to Silicon Valley Bank

S-1

333-194442

March 10, 2014

10.18

10.20

Form of Stock Purchase Warrant of the Registrant to purchase shares of Series C Convertible Preferred Stock

S-1

333-194442

March 10, 2014

10.19

10.21

Preferred Stock Purchase Warrant to purchase shares of Series D Convertible Preferred Stock issued by the Registrant to Lighthouse Capital Partners VI, L.P., as amended

S-1

333-194442

March 10, 2014

10.20

10.22#

Amended and Restated Employment Agreement dated March 27, 2015 between the Registrant and Christopher D. T. Guiffre

S-1

333-202917

March 30, 2015

10.26

10.23

Lease, dated July 9, 2015, between the Registrant and AstraZeneca Pharmaceuticals Limited Partnership

10-Q

001-36395

August 6, 2015

10.1

10.24#

Consulting Agreement, dated May 27, 2015, between the Registrant and Danforth Advisors LLC

10-Q

001-36395

August 6, 2015

10.2

10.25#

Employment Agreement, dated September 4, 2015, between the Registrant and Adrian Senderowicz, M.D.

10-Q

001-36395

November 16, 2015

10.3

10.26#

Employment Agreement, dated September 23, 2014, between the Registrant and Alejandra V. Carvajal

10.27#

Amendment to Employment Agreement dated December 1, 2015, between the Registrant and Alejandra V. Carvajal

10.28#

Stock Option Agreement and Contingent Consideration Award Agreement, dated March 31, 2013, between the Registrant and Alan Crane

S-1

333-194442

March 10, 2014

10.24

10.29#

Amendment to the Stock Option Agreement and Termination of Contingent Consideration Award dated September 16, 2014, by and between the Registrant and Alan Crane

10-Q

001-36395

November 13, 2014

10.4

21.1

Subsidiaries of the Registrant

23.1

Consent of Deloitte & Touche LLP

31.1

Certification of principal executive officer pursuant to Rule 13a-14(a)/15d 14(a) of the Securities Exchange Act of 1934, as amended

31.2

Certification of principal financial officer pursuant to Rule 13a-14(a)/15d-14(a) of the Securities Exchange Act of 1934, as amended

Delaware		20-4139823
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

35 Gatehouse Drive Waltham, MA		02451
(Address of principal executive offices)		(Zip Code)

Title of each class		Name of each exchange on which registered
Common Stock, $0.0001 par value per share		The NASDAQ Global Market

Large accelerated filer	¨		Accelerated filer	x

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

Item No.		Page No.
PART I
Item 1.	Business	1
Item 1A.	Risk Factors	30
Item 1B.	Unresolved Staff Comments	66
Item 2.	Properties	66
Item 3.	Legal Proceedings	66
Item 4.	Mine Safety Disclosures	66

PART II
Item 5.	Market for Registrant’s Common Shares, Related Stockholder Matters and Issuer Purchases of Equity Securities	67
Item 6.	Selected Financial Data	69
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	70
Item 7A.	Quantitative and Qualitative Disclosures about Market Risk	84
Item 8.	Financial Statements and Supplementary Data	85
Item 9.	Changes In and Disagreements with Accountants on Accounting and Financial Disclosure	105
Item 9A.	Controls and Procedures	105
Item 9B.	Other Information	105

PART III
Item 10.	Directors, Executive Officers and Corporate Governance	106
Item 11.	Executive Compensation	106
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	106
Item 13.	Certain Relationships and Related Transactions, and Director Independence	107
Item 14.	Principal Accountant Fees and Services	107

PART IV
Item 15.	Exhibits and Financial Statement Schedules	108

	Common Stock Price
	High		Low
Fiscal year ended December 31, 2015
First Quarter	$	10.87	$	5.68
Second Quarter	$	9.24	$	4.25
Third Quarter	$	5.20	$	2.77
Fourth Quarter	$	4.30	$	2.79
Fiscal year ended December 31, 2014
Second Quarter (from April 10, 2014)	$	8.06	$	5.05
Third Quarter	$	7.30	$	3.35
Fourth Quarter	$	6.45	$	3.95

	Payments Due by Period ($)
Contractual Obligations	Total		Less than 1 year		1 to 3 years		3 to 5 years		More than 5 years
Operating Lease Obligations(1)	$	3,759	$	575	$	1,428	$	1,756	—
Debt Obligations(2)	$	24,445	$	9,215	$	15,230	—		—

		Page
Report of Independent Registered Public Accounting Firm		86
Consolidated Balance Sheets as of December 31, 2015 and 2014		87
Consolidated Statements of Operations for the years ended December 31, 2015, 2014 and 2013		88
Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) for the years ended December 31, 2015, 2014 and 2013		89
Consolidated Statements of Cash Flows for the years ended December 31, 2015, 2014 and 2013		90
Notes to Consolidated Financial Statements		91

Laboratory equipment		5 years
Computer equipment		3 years
Office furniture and equipment		5 years
Leasehold improvements		Lesser of useful life or remaining lease term

Year Ending December 31,
2016	$	7,945
2017		8,544
2018		4,511
Unamortized discount relating to warrants and deferred financing costs		(676	)
Total		20,324
Less current portion		(7,652	)
Long-term portion	$	12,672

	January 8, 2015
Contractual life	5 years
Volatility rate		61	%
Risk-free interest rate		1.5	%
Expected dividends		—

			Fair Value Measurements Using
	Carrying		Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Value		(Level 1)		(Level 2)		(Level 3)
December 31, 2015
Money market funds	$	75,325	$	—	$	75,325	$	—
December 31, 2014
Money market funds	$	50,541	$	—	$	50,541	$	—

	Preferred Stock Warrant
	Series B			Series C			Series D			Total
Balance — December 31, 2013		4			386			538			928
Fair value reclassified to additional paid-in capital in connection with the completion of the IPO on April 15, 2014		(4	)		(386	)		(538	)		(928	)
Balance — December 31, 2014	$	—		$	—		$	—		$	—

		December 31, 2013
Expected life		4-8 years
Risk-free interest rate		2.90%
Expected volatility		64%-84%
Expected dividend rate		—%

	2015			2014
Net operating loss carryforwards	$	35,797		$	29,442
Research and development credit carryforwards		2,066			1,715
Capitalized costs		3,977			3,503
Capitalized research and development costs		17,715			9,938
Other		903			422
Total deferred tax assets		60,458			45,020
Valuation allowance		(60,458	)		(45,020	)
Net deferred tax assets	$	—		$	—

	Operating
Years Ending December 31,	Leases
2016	$	575
2017		690
2018		738
2019		786
2020		830
2021		140
Total	$	3,759

	CERULEAN PHARMA INC.

	By:	/s/ Christopher D. T. Guiffre
		Christopher D. T. Guiffre
		President and Chief Executive Officer
		(Principal Executive Officer)

Date: March 10, 2016