S-1

As filed with the Securities and Exchange Commission on October 10, 2017

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ANAPTYSBIO, INC.

(Exact name of registrant as specified in its charter)

Delaware	2834	20-3828755
(State or other jurisdiction of incorporation or organization)	(Primary Standard Industrial Classification Code Number)	(I.R.S. Employer Identification Number)

10421 Pacific Center Court, Suite 200

San Diego, CA 92121

(858) 362-6295

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Hamza Suria

Chief Executive Officer

AnaptysBio, Inc.

10421 Pacific Center Court, Suite 200

San Diego, CA 92121

(858) 362-6295

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Effie Toshav, Esq. Matthew S. Rossiter, Esq. Robert A. Freedman, Esq. Fenwick & West LLP 555 California Street San Francisco, CA 94104 (415) 875-2300 Charles S. Kim, Esq. Sean M. Clayton, Esq. Jonie I. Kondracki, Esq. Cooley LLP 4401 Eastgate Mall San Diego, CA 92121 (858) 550-6000

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement.

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box.  ☐

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration number of the earlier effective registration statement for the same offering.  ☐

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

Large accelerated filer	☐	Accelerated filer	☐
Non-accelerated filer	☒ (Do not check if a smaller reporting company)	Smaller reporting company	☐
		Emerging Growth Company	☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided to Section 7(a)(2)(B) of the Securities Act.  ☒

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities to be Registered	Amount to be Registered(1)	Proposed Maximum Offering Price Per Share(2)	Proposed Maximum Aggregate Offering Price(1)(2)	Amount of Registration Fee(2)
Common stock, par value $0.001 per share……………...	3,450,000	$35.10	$121,095,000	$15,077

(1) Includes 450,000 shares of common stock that the underwriters have the option to purchase.

(2) Estimated solely for the purposes of calculating the amount of the registration fee in accordance with Rule 457(c) under the Securities Act of 1933, as amended, and is based on the average of the high and low sales prices of the registrant’s common stock as reported on The NASDAQ Stock Market LLC on October 9, 2017.

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED OCTOBER 10, 2017

3,000,000 Shares

Common Stock

We are offering 3,000,000 shares of our common stock.

Our common stock is listed on The NASDAQ Global Select Market under the symbol “ANAB”. The last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017 was $35.00 per share. The final public offering price will be determined through negotiation between us and the lead underwriters in the offering and the recent market price used throughout this prospectus may not be indicative of the final offering price.

We have granted the underwriters a 30-day option to purchase up to 450,000 additional shares from us at the public offering price, less the underwriting discounts and commissions.

We are an “emerging growth company” as the term is used in the Jumpstart Our Business Startups Act of 2012 and, as such, have elected to comply with certain reduced public company reporting requirements for this prospectus, the documents incorporated by reference herein and future filings.

Investing in our common stock involves a high degree of risk. See “Risk Factors” on page 15 of this prospectus.

	Price to Public	Underwriting Discounts and Commissions(1)	Proceeds to AnaptysBio, Inc.
Per Share	$	$	$
Total	$	$	$

(1) See “Underwriting” for a description of the compensation payable to the underwriters.

Neither the Securities and Exchange Commission, any state securities commission nor any other regulatory body has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares on or about                 , 2017.

Credit Suisse Jefferies Stifel

The date of this prospectus is                 , 2017.

TABLE OF CONTENTS

	Page
PROSPECTUS SUMMARY		1
THE OFFERING		11
RISK FACTORS		15
SPECIAL NOTE REGARDING FORWARD -LOOKING STATEMENTS		16
MARKET AND INDUSTRY DATA		18
USE OF PROCEEDS		19
DIVIDEND POLICY		20
CAPITALIZATION		21
DILUTION		23
CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS		25
PRINCIPAL STOCKHOLDERS		28
DESCRIPTION OF CAPITAL STOCK		31
MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS		36
UNDERWRITING		41
LEGAL MATTERS		53
EXPERTS		53
ADDITIONAL INFORMATION		53
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE		53

You should rely only on the information contained or incorporated by reference in this prospectus or to which we have referred you. Neither we nor the underwriters have authorized anyone to provide you with information that is different. This prospectus may only be used where it is legal to sell these securities. The information in this prospectus or in any document incorporated by reference herein may only be accurate as of the date hereof or thereof, respectively, regardless of the time of delivery of this prospectus or of any sale of shares of our common stock and the information in any free writing prospectus that we may provide you in connection with this offering is accurate only as of the date of that free writing prospectus. Our business, financial condition, results of operations and future growth prospects may have changed since those dates.

Persons who come into possession of this prospectus and any applicable free writing prospectus in jurisdictions outside the United States are required to inform themselves about and to observe any restrictions as to this offering and the distribution of this prospectus and any such free writing prospectus applicable to that jurisdiction.

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PROSPECTUS SUMMARY

This summary highlights selected information contained elsewhere in this prospectus and does not contain all of the information that you should consider in making your investment decision. Before investing in our common stock, you should carefully read this entire prospectus, including our consolidated financial statements and the related notes thereto and the information set forth under the sections “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” in each case included in, or incorporated by reference into, this prospectus. Unless the context otherwise requires, we use the terms “AnaptysBio,” “company,” “we,” “us” and “our” in this prospectus to refer to AnaptysBio, Inc. and our subsidiary.

Overview

We are a clinical stage biotechnology company developing first-in-class antibody product candidates focused on unmet medical needs in inflammation. We develop our product candidates to address emerging biological targets using our proprietary antibody discovery technology platform, which is based upon a breakthrough understanding of the natural process of antibody generation, known as somatic hypermutation, or SHM, and replicates this natural process of antibody generation in vitro. Our strategy is to advance the development and commercialization of our proprietary product candidates, and for certain programs, establish partnerships with leading biopharmaceutical companies where we retain certain development and commercialization rights in the United States.

Our most advanced wholly-owned antibody programs, ANB020 and ANB019, neutralize therapeutic targets that are genetically associated with severe inflammatory disorders in humans. ANB020 inhibits the activity of the interleukin-33 cytokine, or IL-33, for the treatment of moderate-to-severe adult atopic dermatitis, severe adult peanut allergy and severe adult eosinophilic asthma. We have completed a Phase 1 trial of ANB020 in healthy volunteers in Australia, the results of which were presented at the 2017 American Academy of Dermatology Annual Meeting and the American Academy of Allergy, Asthma and Immunology 2017 Annual Meeting in March 2017. We believe the results of this Phase 1 trial demonstrate a favorable safety profile of ANB020, which was well-tolerated and for which no dose-limiting toxicities were observed, and favorable pharmacodynamic properties of ANB020, where a single dose was sufficient to suppress IL-33 function for approximately three months post-dosing as measured by an ex vivo pharmacodynamic assay. We have subsequently completed enrollment of a Phase 2a trial of ANB020 in 12 moderate-to-severe adult atopic dermatitis patients, under an approved Clinical Trial Authorisation, or CTA, with the U.K. Medicines and Healthcare Products Regulatory Agency, or MHRA, and announced top-line data from an interim analysis of this trial in October 2017.

The Phase 2a proof-of-concept trial enrolled 12 moderate-to-severe adult atopic dermatitis patients, who were initially administered a single intravenous dose of placebo within 14 days of enrollment, followed by a single intravenous 300mg dose of ANB020 one week subsequent to placebo. Prior to enrollment in the study, patients were not permitted any systemic or topical medications during a wash-out period. Patients were permitted to take a monitored amount of topical corticosteroids as rescue therapy during the course of the study. Clinical response was assessed by a number of endpoints, including the improvement of each patient’s Eczema Area Severity Index, or EASI, score, a tool used to measure the extent and severity of atopic dermatitis, at key time points following ANB020 administration relative to their enrollment baseline. Pruritus, also known as itchiness, as measured by the 5-D pruritus scale score, was also assessed for each patient. Exploratory mechanistic biomarkers included granulocyte infiltration and cytokine levels in localized skin lesions measured five days after placebo administration and five days after ANB020 administration.

Top-line data indicated rapid and sustained clinical achievement of EASI-50, which is 50% or better improvement in EASI score relative to enrollment baseline, in 83% of patients at Day 29, and the 5-D pruritus score was reduced by 32% relative to enrollment baseline. As early as Day 15 post-ANB020 administration 75% of patients

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reached EASI-50 and pruritus was reduced by 28%, which was sustained until Day 57 when 75% of patients achieved EASI-50; pruritus was reduced by 22% at Day 57. All 12 patients achieved EASI-50 at one or more timepoints through Day 57 post-ANB020 administration. Exploratory biomarker assessment indicated reduction of granulocyte infiltration into localized skin lesions by an average of 30% amongst all patients and 60% among the 10 patients achieving EASI-50 at 29 days post-ANB020 administration, while exploratory cytokine biomarker levels were below detection limit and therefore inconclusive. ANB020 was generally well-tolerated by all patients and no severe adverse events have been reported to date. The most frequent treatment-emergent adverse events reported were mild dizziness in two patients subsequent to placebo dosing, and mild headache in two patients post-ANB020 administration. We plan to report full data from this trial, including results on additional clinical measures, at a medical conference following study completion and further data analysis.

The chart below summarizes the EASI score improvement and average percent reduction of pruritus scores at various time points through day 57 of the trial.

We believe these data demonstrate proof-of-concept for ANB020 in moderate-to-severe adult atopic dermatitis and suggest that ANB020 may provide meaningful differentiation in terms of patient convenience. As further development in atopic dermatitis, we plan to initiate, during the first half of 2018, a Phase 2b randomized, double-blinded, placebo-controlled study in 200-300 adults patients with moderate-to-severe atopic dermatitis to evaluate multi-dose subcutaneous administration of ANB020, with data expected in 2019.

We are continuing to enroll, under our Investigational New Drug application, or IND, with the U.S. Food and Drug Administration, or FDA, a Phase 2a trial of ANB020 with 20 severe adult peanut allergy patients where efficacy is assessed by measuring the cumulative dose of peanut tolerated in an oral food challenge before and after a single dose of ANB020 or placebo. Top-line data are anticipated during the fourth quarter of 2017. We have also initiated enrollment, under a CTA with MHRA, of a Phase 2a trial of ANB020 in 24 severe adult eosinophilic asthma patients, where efficacy will be assessed using improvement in Forced Expiratory Volume in One Second after administration of a single dose of ANB020 or placebo. Top-line data are anticipated during the first half of 2018.

ANB019 inhibits the interleukin-36 receptor, or IL-36R, for the treatment of rare inflammatory diseases including generalized pustular psoriasis, or GPP, and palmo-plantar pustular psoriasis, or PPP. We are currently

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conducting, under an approved Clinical Trial Notification, or CTN, a Phase 1 clinical trial in healthy volunteers, where 48 subjects are dosed with ANB019 and 24 are dosed with placebo in single and multi-dose cohorts at various subcutaneous and intravenously administered dose levels, to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of ANB019 and anticipate announcing top-line data from this trial during the fourth quarter of 2017. We subsequently plan to seek regulatory clearance to initiate Phase 2 studies of ANB019 in GPP and PPP patients during 2018. In addition to ANB020 and ANB019, our wholly-owned pipeline includes novel checkpoint receptor agonist antibodies that we believe are applicable for treatment of certain autoimmune diseases where immune checkpoint receptors are insufficiently activated, and have demonstrated efficacy in an animal model of graft-versus-host disease.

In addition to our wholly-owned antibody programs, multiple AnaptysBio-developed antibody programs have been advanced under our collaborations to preclinical and clinical milestones. Our collaborations include an immuno-oncology-focused collaboration with TESARO, Inc. and TESARO Development, Ltd., or collectively, TESARO, and an inflammation-focused collaboration with Celgene Corporation, or Celgene.

Under our TESARO collaboration, TESARO has initiated a registration program under an IND with the FDA of an AnaptysBio-generated anti-PD-1 antagonist antibody (TSR-042) in metastatic microsatellite high endometrial cancer patients. TESARO has completed dose escalation of an AnaptysBio-generated anti-TIM-3 antagonist antibody (TSR-022) in patients under an IND and has subsequently initiated a combination study of TSR-022 and TSR-042. In addition, TESARO has initiated a Phase 1 study of an AnaptysBio-generated anti-LAG-3 antibody (TSR-033), and TESARO has initiated IND-enabling preclinical studies for an AnaptysBio-generated PD-1/LAG-3 bispecific antibody, which has exhibited similar levels of T-cell activation in vitro as a combination of TSR-042 and TSR-033.

Under our collaboration with Celgene, Celgene is advancing two AnaptysBio-generated anti-inflammatory antibody programs. One of these programs is an anti-PD-1 agonist antibody (CC-90006) currently in a Phase 1 trial for psoriasis.

Through June 30, 2017, we have received $73.6 million in non-dilutive funding from our collaborators.

Our company is led by a strong management team with deep experience in antibody discovery and development, collaborations, operations and corporate finance.

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Our Product Candidates

We have developed, and will continue to develop, antibody product candidates that leverage emerging insights into biological mechanisms to treat severe diseases with unmet medical need. The following table summarizes certain key information about our wholly-owned and partnered product candidates:

Our most advanced, wholly-owned product candidates are summarized below:

• ANB020 is a potentially first-in-class antibody that inhibits the activity of IL-33, a pro-inflammatory cytokine that multiple studies have indicated is a central mediator of atopic diseases, including atopic dermatitis, food allergies and asthma. IL-33 directly mediates release of disease-associated cytokines, which recruit pro-inflammatory cells that mediate atopic disease. Because ANB020 inhibits IL-33 function, and acts upstream broadly across the key cell types and cytokines involved in atopy, we believe that its mechanism has advantages in the treatment of atopic diseases over competing agents that block only a subset of the cytokines responsible for atopic diseases. The role of IL-33 signaling in asthma has been recently genetically validated through human studies published in the medical literature. We have completed a Phase 1 trial of ANB020 in healthy volunteers in Australia. We believe the results of this Phase 1 trial demonstrate a favorable safety profile of ANB020, which was well-tolerated and for which no dose-limiting toxicities were observed, and favorable pharmacodynamic properties of ANB020, where a single dose was sufficient to suppress IL-33 function for approximately three months post-dosing as measured by an ex vivo pharmacodynamic assay. We presented these results at the 2017 American Academy of Dermatology Annual Meeting and the American Academy of Allergy, Asthma and Immunology 2017 Annual Meeting in March 2017. We have subsequently completed enrollment of a Phase 2a trial where a single dose of ANB020 was administered to 12 moderate-to-severe adult atopic

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dermatitis patients, under an approved Clinical Trial Authorisation, or CTA, with the U.K. Medicines and Healthcare Products Regulatory Agency, or MHRA, and, announced top-line data from an interim analysis of this trial in October 2017. Top-line data indicated rapid and sustained achievement of EASI-50, which is 50% or better improvement in EASI score relative to enrollment baseline, in 83% of patients at day 29, and reduced the 5-D pruritus score, which is a measure of itching, by 32% relative to enrollment baseline. As early as Day 15 post-ANB020 administration 75% of patients reached EASI-50 and pruritus was reduced by 28%, which was sustained until Day 57 when 75% of patients achieved EASI-50; pruritus was reduced by 22% at Day 57. No severe adverse events have been reported to date under this study. We believe these data demonstrate proof-of-concept for ANB020 in moderate-to-severe adult atopic dermatitis and provide meaningful differentiation in terms of patient convenience. As further development in atopic dermatitis, we plan to initiate, during the first half of 2018, a Phase 2b randomized, double-blinded, placebo-controlled study in 200-300 adults patients with moderate-to-severe atopic dermatitis to evaluate multi-dose subcutaneous administration of ANB020, with data expected in 2019. We have also initiated, under our IND a Phase 2a trial of ANB020 in the United States with 20 severe adult peanut allergy patients where efficacy will be assessed by measuring the cumulative dose of peanut tolerated in an oral food challenge before and after a single dose of ANB020 or placebo. We anticipate top-line data from this trial will be available during the fourth quarter of 2017. We have also initiated enrollment, under a CTA with the MHRA, of a Phase 2a trial of ANB020 with 24 severe adult eosinophilic asthma patients, where efficacy will be assessed using improvement in Forced Expiratory Volume in One Second after administration of a single dose of ANB020 or placebo. Top-line data are anticipated during the first half of 2018. Based on our analysis of publicly available data sources and interviews with physicians and key opinion leaders in the field of atopic dermatitis, we estimate approximately 1.4 million adults in the United States are affected by atopic dermatitis, of which approximately 280,000 are diagnosed with a moderate-to-severe form of this disease, of which 98,000 are believed to be suitable for treatment with systemic biological therapies. Peanut allergy is the most common cause of food-induced allergy in the United States. Based on our analysis of publicly available data sources and interviews with physicians and key opinion leaders in the food allergy field, we estimate approximately 1.7 million adults are affected by peanut allergy, of which approximately 600,000 are treated by allergists and approximately 400,000 are at risk for severe reactions and therefore we believe are suitable for treatment with systemic biological therapies in the United States. We estimate, based on our analysis of publicly available data sources and interviews with physicians and key opinion leaders focused on asthma, that asthma affects approximately 19.0 million individuals, of which approximately 1.1 million have severe, persistent occurrence of this respiratory disease in the United States that cannot be controlled by standard-of-care therapy.

• ANB019 is an antibody that inhibits the function of IL-36R, which we are initially developing as a potential first-in-class therapy for GPP and PPP patients. GPP is a life-threatening, rare, systemic inflammatory disorder that, based on our analysis of publicly available data sources and interviews with physicians and key opinion leaders in the field, we estimate affects approximately 3,000 patients in the United States with no approved therapies. Studies have shown that GPP can be associated in some patients with mutations that lead to abnormally high signaling through the IL-36R, which we believe can be addressed by treatment with ANB019 irrespective of whether a GPP patient has a mutated IL-36R signaling pathway. PPP is a non-fatal form of pustular psoriasis that we estimate affects approximately 150,000 patients in the United States alone. PPP is believed to be caused by increased systemic levels of interleukin-36 resulting in inflammatory pustules on the hands and feet of patients that cause significant inability to stand, walk or do manual work, which we believe can be addressed by treatment with ANB019. We believe ANB019 is the most advanced therapeutic antibody targeting IL-36R in development. We are currently conducting, under an approved CTN, a Phase 1 clinical trial in healthy volunteers, where 48 subjects are dosed with ANB019 and 24 are dosed with placebo in single and multi-dose cohorts at various subcutaneous and intravenously administered dose levels, to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of ANB019 and anticipate announcing top-line data from this trial during the fourth quarter of 2017. We subsequently plan to seek regulatory clearance

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to initiate Phase 2 studies of ANB019 in GPP and PPP patients during 2018. We plan to seek FDA Orphan Drug Designation for the treatment of GPP and PPP. The FDA may grant Orphan Drug Designation to a drug intended to treat a disease or condition that generally affects fewer than 200,000 individuals in the United States.

• Checkpoint receptor agonist antibodies are being developed by AnaptysBio to multiple different immune checkpoint receptors for the treatment of certain autoimmune diseases where we believe checkpoint receptor function is insufficiently activated. Known human immune checkpoint receptors include CTLA-4, PD-1, LAG-3, BTLA and TIGIT. We have discovered certain checkpoint receptor agonist antibodies that have demonstrated efficacy in a rodent model of graft-versus-host disease. We anticipate that, subsequent to regulatory clearance, one of our wholly-owned checkpoint receptor antibodies will initiate human testing during 2019.

The Advantages of Our SHM Platform

Our approach to developing novel therapeutic antibody product candidates is based upon SHM, a critical, endogenous process that generates the essential antibody diversity required to develop a natural immune response to pathogens. Our proprietary antibody generation platform is designed to replicate the natural process of SHM in vitro. Competing antibody discovery technologies include mouse immunization methodologies, microbial antibody display and human B-cell screening. We believe our SHM platform overcomes several key limitations associated with these competing technologies and has the following competitive advantages:

• Diversity against difficult targets. By applying SHM without the constraints of an in vivo environment we are able to generate an unprecedented diversity of antibodies. This enables us to develop antibodies against human targets that we believe have not otherwise been accessible to other technologies.

• High potency. Because our platform generates highly-potent antibodies, we are potentially able to modulate every extracellular target associated with human disease, and believe only small therapeutic doses may be required to mediate therapeutic effect in vivo.

• Functional activity selection. Our mammalian cell system simultaneously displays and secretes antibodies during the antibody discovery process, allowing us to incorporate functional assays throughout the process and focus on product candidates that are optimized for the desired therapeutic activity.

• Speed. Our platform technology has enabled us to generate therapeutic-grade antibodies and subsequently advance preclinical manufacturing and toxicology studies to the filing of an IND or foreign equivalent, typically in approximately 2.5 years. We believe this timeline is significantly shorter than conventional antibody discovery approaches based upon mouse immunization and microbial display systems.

• Manufacturability. By using mammalian cell display to generate our therapeutic antibodies, we believe our platform mitigates risks associated with antibody expression, formulation and stability during the antibody generation process.

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Our Collaborations

We have established collaborations with pharmaceutical and biotechnology companies that have provided us with $73.6 million in payments through June 30, 2017. Multiple antibodies, generated by us prior to or during a strategic collaboration, are currently being advanced through development by our collaborators. Our collaborations with TESARO and Celgene are described below:

TESARO Programs

Under our immuno-oncology collaboration with TESARO, we have granted exclusive rights to TESARO to develop and commercialize antibodies generated using our SHM platform consisting of the following antibody product candidates:

• Anti-PD-1 Monospecific Antagonist Antibody (TSR-042): Registration program initiated for metastatic microsatellite instability high (MSI-H) endometrial cancer;

• Anti-TIM-3 Monospecific Antagonist Antibody (TSR-022): Dose escalation completed in Phase 1, combination trial with TSR-042 has been initiated;

• Anti-LAG-3 Monospecific Antagonist Antibody (TSR-033): Phase 1 trial initiated, and

• Anti-PD-1/LAG-3 Bispecific Antagonist Antibody: lead candidate identified, IND-enabling studies on-going.

Celgene Programs

Under our collaboration with Celgene, we developed therapeutic antibodies against multiple targets. We granted Celgene the option to obtain worldwide commercial rights to antibodies generated against each of the targets under the agreement, which option was triggered on a target-by-target basis by our delivery of antibodies meeting certain pre-specified parameters pertaining to each target under collaboration. Celgene is currently advancing two AnaptysBio-generated anti-inflammatory antibody programs, where one of these programs is an anti-PD-1 agonist antibody (CC-90006) currently in a Phase 1 trial for psoriasis.

Milestones

We anticipate the following milestones relating to wholly-owned pipeline programs to be attained during the remainder of 2017 and 2018:

Program	Milestone	Timing
ANB020 (Anti-IL-33)	Atopic Dermatitis Phase 2a Top-Line Data	Announced October 2017
	Peanut Allergy Phase 2a Top-Line Data	Q4 2017
	Eosinophilic Asthma Phase 2a Top-Line Data	H1 2018
ANB019  (anti-IL-36R)	Healthy Volunteer Phase 1 Top-Line Data	Q4 2017
	GPP Phase 2 Initiation	2018
	PPP Phase 2 Initiation	2018

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Our Strategy

We are a leading antibody development company with a pipeline of novel therapeutic antibodies, which is being further expanded by applying our technology platform to emerging biological targets. The key elements of our strategy include:

• Advancing our wholly-owned lead product candidates to clinical milestones. We are conducting clinical trials to assess the safety and efficacy of our wholly-owned pipeline programs, and have completed a Phase 1 trial of ANB020 in healthy volunteers in Australia, which we believe has demonstrated favorable safety and ex vivo pharmacodynamic properties. We are conducting multiple Phase 2a trials of ANB020: top-line results from a Phase 2a trial in patients with moderate-to-severe adult atopic dermatitis were announced in October 2017; top-line data from a Phase 2a trial in patients with severe adult peanut allergy are anticipated in the fourth quarter of 2017; and top-line data from a Phase 2a trial in patients with severe adult eosinophilic asthma are anticipated during the first half of 2018. We are currently conducting, under an approved CTN, a Phase 1 clinical trial in healthy volunteers, where 48 subjects are dosed with ANB019 and 24 are dosed with placebo in single and multi-dose cohorts at various subcutaneous and intravenously administered dose levels, to assess the safety, tolerability, pharmacokinetics and pharmacodynamics of ANB019 and anticipate announcing top-line data from this trial during the fourth quarter of 2017. We subsequently plan to seek regulatory clearance to initiate Phase 2 studies of ANB019 in GPP and PPP patients during 2018.

• Continuing to expand our proprietary pipeline by generating new product candidates using our technology platform. Using our proprietary SHM antibody generation platform, we are able to rapidly develop novel antibodies against biological emerging targets. Our goal is to continue expanding our wholly-owned new therapeutic antibody program pipeline by innovating one or more novel pipeline antibodies each year.

• Identifying emerging opportunities in key therapeutic areas. We intend to remain at the forefront of discovery and development of new therapeutic opportunities in inflammation by understanding and translating biological breakthroughs into first-in-class therapeutic antibodies. Our approach includes translational biology assessments, such as human genetics, ex vivo tissue pathology and target expression patterns, to understand the relevance of emerging targets to patients with unmet medical needs. We plan to leverage this knowledge to create new product candidates and position our current and future programs for rapid initial efficacy assessment.

• Retaining rights to strategic products in key commercial markets. We intend to retain ownership and control of our pipeline programs to key preclinical and clinical data inflection points. We may build sales and marketing capabilities in the United States with a focused commercial organization. For certain programs, we plan to seek strategic collaborations that provide us with funding, infrastructure and marketing resources to advance through development and commercialization.

Financial Update

While we have not finalized our full financial results for the quarter ended September 30, 2017, we expect to report that we had $116.7 million of cash and cash equivalents and investments as of September 30, 2017. This amount is preliminary, has not been audited and is subject to change upon completion of our quarterly review. Additional information and disclosures would be required for a more complete understanding of our financial position and results of operations as of September 30, 2017.

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Risks Affecting Us

Our business is subject to a number of risks and uncertainties, including those highlighted and incorporated by reference in the section titled “Risk Factors” immediately following this prospectus summary. These risks include, among others, the following:

• Our product candidates are in early stages of development and may fail in development or suffer delays that adversely affect their commercial viability. If we or our collaborators are unable to complete development of or commercialize our product candidates or experience significant delays in doing so, our business will be materially harmed.

• We have only limited data regarding the safety profile of our wholly-owned product candidates when dosed in humans. Our ongoing and planned clinical trials or those of our collaborators may demonstrate limited efficacy or reveal significant adverse events, toxicities or other side effects and may result in an efficacy or safety profile that could inhibit regulatory approval or market acceptance of any of our product candidates.

• We and/or our collaborators may be unable to obtain, or may be delayed in obtaining, required regulatory approvals in the United States or in foreign jurisdictions, which would materially impair our ability to commercialize and generate revenue from our product candidates.

• We may not be successful in our efforts to use our technology platform to expand our pipeline of product candidates and develop marketable products.

• We have only recently commenced clinical development of ANB019 and ANB020 and have no other history of conducting clinical trials or commercializing biotechnology products, which may make it difficult to evaluate the prospects for our future viability.

• We face significant competition, and if our competitors develop and market products that are more effective, safer or less expensive than our product candidates, our commercial opportunities will be negatively impacted.

• Our existing collaborations, including those with TESARO and Celgene, are important to our business, and future collaborations may also be important to us. If we are unable to maintain any of these collaborations, or if these collaborations are not successful, our business could be adversely affected.

• The manufacture of biologics is complex and our third-party manufacturers may encounter difficulties in production. If any of our third-party manufacturers encounter such difficulties, our ability to provide supply of our product candidates for clinical trials or our products for patients, if approved, could be delayed or stopped.

• We have limited operating revenue and a history of operational losses and may not achieve or sustain profitability. We have no products approved for commercial sale, and to date we have not generated any revenue or profit from product sales.

• We will require additional capital to finance our operations, which may not be available to us on acceptable terms, or at all. As a result, we may not complete the development and commercialization of our product candidates or develop new product candidates.

Corporate Information

We were incorporated under the laws of the State of Delaware in November 2005. Our principal executive offices are located at 10421 Pacific Center Court, Suite 200, San Diego, California 92121, and our telephone number is (858) 362-6295. Our website address is www.anaptysbio.com. The information contained on, or that can be accessed through, our website is not part of, and is not incorporated by reference into, this prospectus. Investors should not rely on any such information in deciding whether to purchase our common stock.

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The mark “AnaptysBio” is our common law trademark. All other service marks, trademarks and trade names appearing in this prospectus are the property of their respective owners.

Implications of Being an Emerging Growth Company

As a company with less than $1.07 billion in revenue during our last fiscal year, we qualify as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or JOBS Act, enacted in April 2012. An “emerging growth company” may take advantage of reduced reporting requirements that are otherwise applicable to public companies. These provisions include, but are not limited to:

• not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, or the Sarbanes-Oxley Act;

• reduced disclosure obligations regarding executive compensation in our periodic reports, proxy statements and registration statements; and

• exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved.

We may use these provisions until the last day of our fiscal year following the fifth anniversary of the closing of our initial public offering. However, if certain events occur prior to the end of such five-year period, including if we become a “large accelerated filer,” our annual gross revenues exceed $1.07 billion or we issue more than $1.0 billion of non-convertible debt in any three-year period, we will cease to be an emerging growth company prior to the end of such five-year period.

We have elected to take advantage of certain of the reduced disclosure obligations in the registration statement of which this prospectus is a part and the documents incorporated herein by reference and may elect to take advantage of other reduced reporting requirements in future filings. As a result, the information that we provide to our stockholders may be different than you might receive from other public reporting companies in which you hold equity interests.

The JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. We have irrevocably elected not to avail ourselves of this exemption and, therefore, we are subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

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THE OFFERING

Shares of common stock offered by us 3,000,000 shares.

Option to purchase additional shares to be
offered by us 450,000 shares.

Shares of common stock to be outstanding immediately after this offering
23,289,907 shares (23,739,907 shares if the underwriters exercise their option to purchase additional shares in full).

Use of proceeds We estimate that the net proceeds from this offering will be approximately $98.6 million (or approximately $113.4 million if the underwriters exercise their option to purchase additional shares in full), based upon the assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

We intend to use the net proceeds that we receive in this offering to fund research and development activities for our clinical development programs, our ongoing preclinical, discovery and research programs, and for working capital and other general corporate purposes. We may use a portion of the proceeds to acquire other complementary businesses or technologies, although we have no present commitments or agreements to do so. See “Use of Proceeds” for a more complete description of the intended use of proceeds from this offering.

Risk factors You should read the “Risk Factors” section of this prospectus for a discussion of factors to consider carefully before deciding to invest in shares of our common stock.

Nasdaq Global Select Market symbol “ANAB”

The number of shares of our common stock to be outstanding after this offering is based on 20,289,907 shares of our common stock outstanding as of June 30, 2017, and excludes:

• 2,643,180 shares of common stock issuable upon the exercise of options outstanding as of June 30, 2017, with a weighted-average exercise price of $10.62 per share;

• 96,965 shares of common stock issuable upon the exercise of options granted after June 30, 2017, with a weighted-average exercise price of $26.77 per share;

• 198,009 shares of our common stock issuable upon exercise of warrants outstanding as of June 30, 2017, with an exercise price of $4.55 per share; and

• 1,462,014 shares of common stock reserved for future issuance under our stock-based compensation plans as of June 30, 2017, consisting of (a) 1,244,014 shares of common stock reserved for future issuance under our 2017 Equity Incentive Plan and (b) 218,000 shares of common stock reserved for future

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issuance under our 2017 Employee Stock Purchase Plan. Our 2017 Equity Incentive Plan and 2017 Employee Stock Purchase Plan also provide for automatic annual increases in the number of shares reserved under the plans each year, as more fully described in note 8 of the notes to our unaudited consolidated financial statements included in our Quarterly Report on Form 10-Q for the period ended June 30, 2017.

Except as otherwise indicated, all information in this prospectus assumes no exercise of outstanding options or warrants and no exercise of the underwriters’ option to purchase additional shares.

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Summary Consolidated Financial Data

The summary consolidated statements of operations data presented below for the years ended December 31, 2014, 2015 and 2016 are derived from our audited financial statements incorporated by reference into this prospectus. The selected consolidated statements of operations data for the six months ended June 30, 2016 and 2017 and the summary consolidated balance sheet data as of June 30, 2017 have been derived from our unaudited consolidated financial statements incorporated by reference into this prospectus. Our unaudited consolidated financial statements have been prepared on the same basis as our audited financial statements and, in the opinion of management, reflect all adjustments, which consist only of normal recurring adjustments, necessary for the fair statement of those unaudited consolidated financial statements. The following summary consolidated financial data should be read with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements and related notes incorporated by reference into this prospectus. Our historical results are not necessarily indicative of the results that may be expected in any future period. The summary financial data in this section are not intended to replace the financial statements and are qualified in their entirety by the financial statements and related notes incorporated by reference into this prospectus.

	Year Ended December 31,									Six Months Ended June 30,
(in thousands, except per share data)	2014			2015			2016			2016			2017
										(unaudited)
Consolidated Statements of Operations Data:
Collaboration revenue	$	15,838		$	17,571		$	16,684		$	10,716		$	7,000
Operating expenses:
Research and development		8,614			17,304			15,419			7,121			15,140
General and administrative		2,354			3,589			4,290			2,371			4,403
Total operating expenses		10,968			20,893			19,709			9,492			19,543
Income (loss) from operations		4,870			(3,322	)		(3,025	)		1,224			(12,543	)
Other income (expense), net
Interest expense		(1,281	)		(460	)		(458	)		(231	)		(867	)
Change in fair value of liability for preferred stock warrants		(59	)		(1,277	)		(756	)		382			(1,366	)
Other income (expense), net		2			(207	)		(20	)		59			657
Total other income (expense), net		(1,338	)		(1,944	)		(1,234	)		210			(1,576	)
Income (loss) before income taxes		3,532			(5,266	)		(4,259	)		1,434			(14,119	)
Provision for income taxes		—			(139	)		—			—			—
Net income (loss)		3,532			(5,405	)		(4,259	)		1,434			(14,119	)
Net income (loss) attributed to participating securities		(3,300	)		—			—			(1,434	)		—
Net income (loss) attributed to common stockholders		232			(5,405	)		(4,259	)		—			(14,119	)
Unrealized loss on available for sale securities		—			—			—			—			(59	)
Other comprehensive loss		—			—			—			—			(59	)
Comprehensive income (loss)	$	232		$	(5,405	)	$	(4,259	)	$	—		$	(14,178	)
Net income (loss) per common share:(1)
Basic and diluted	$	0.09		$	(2.12	)	$	(1.62	)	$	—		$	(0.79	)

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	Year Ended December 31,						Six Months Ended June 30,
(in thousands, except per share data)	2014		2015		2016		2016		2017
							(unaudited)
Weighted-average number of shares outstanding:(1)
Basic		2,481		2,551		2,637		2,632		17,797
Diluted		2,481		2,551		2,637		3,497		17,797

(1) See Note 2 to our audited consolidated financial statements incorporated by reference in this prospectus for an explanation of the method used to calculate basic and diluted net income (loss) per common share and the weighted-average number of shares used in the computation of the per share amounts.

	As of June 30, 2017 (unaudited)
(in thousands)	Actual		As Adjusted(1)(2)
Consolidated Balance Sheet Data:
Cash, cash equivalents, and short-term investments	$	106,359	$	205,002
Total assets		130,409		229,052
Notes payable, net of current portion		10,987		10,987
Total stockholders’ equity		109,175		207,818

(1) The as adjusted balance sheet data give effect to the sale of 3,000,000 shares of common stock by us in this offering, based on an assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

(2) Each $1.00 increase (decrease) in the assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, would increase (decrease) each of our as adjusted cash, cash equivalents, short-term investments, total assets and total stockholders’ equity by approximately $2.8 million, assuming that the number of shares offered by us remains the same and after deducting the estimated underwriting discounts and commissions. Similarly, each increase (decrease) of one million shares in the number of shares offered by us would increase (decrease) each of our as adjusted cash, cash equivalents, short-term investments, total assets and total stockholders’ equity by approximately $32.9 million, assuming the assumed public offering price remains the same and after deducting the estimated underwriting discounts and commissions.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. Before making your decision to invest in shares of our common stock, you should carefully consider the risks described in Part II, Item 1A of our Quarterly Report on Form 10-Q for the period ended June 30, 2017 and Part I, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2016, together with all of the other information contained in or incorporated by reference into this prospectus. We cannot assure you that any of the events discussed herein or therein will not occur. These events could have a material and adverse impact on our business, results of operations, financial condition and cash flows. If that were to happen, the trading price of our common stock could decline, and you could lose all or part of your investment.

Risks Related to this Offering

Our management will have broad discretion over the use of the proceeds we receive in this offering and might not apply the proceeds in ways that increase the value of your investment.

Our management will have broad discretion to use the net proceeds from this offering, including for any of the purposes described in the section entitled “Use of Proceeds,” and you will be relying on the judgment of our management regarding the application of these proceeds. You will not have the opportunity to influence our decisions on how to use the proceeds, and we may not apply the net proceeds of this offering in ways that increase the value of your investment. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. The failure by our management to apply these funds effectively could harm our business. Pending their use, we intend to invest the net proceeds from this offering in marketable securities that may include investment-grade interest-bearing securities, money market accounts, certificates of deposit, commercial paper and guaranteed obligations of the U.S. government. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

If you purchase our common stock in this offering, you will incur immediate and substantial dilution in the book value of your shares.

You will suffer immediate and substantial dilution in the net tangible book value of our common stock you purchase in this offering. Assuming a public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, purchasers of common stock in this offering will experience immediate dilution of $26.08 per share in net tangible book value of our common stock. In the past, we issued options, warrants and other securities to acquire common stock at prices below the public offering price. To the extent these outstanding securities are ultimately exercised, or we issue equity or convertible debt securities in the future at a price less than the public offering price, investors purchasing common stock in this offering will sustain further dilution. See “Dilution” for a more detailed description of the dilution to new investors in the offering.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference into this prospectus, including the sections entitled “Prospectus Summary,” “Risk Factors,” “Use of Proceeds,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and “Business”, contains forward-looking statements. The words “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan” “expect,” and similar expressions that convey uncertainty of future events or outcomes are intended to identify forward-looking statements.

The forward-looking statements in this prospectus and the documents incorporated by reference into this prospectus include, among other things, statements about:

• the success, cost and timing of our product candidate development activities and ongoing and planned clinical trials;

• our plans to develop and commercialize antibodies, including our lead product candidates ANB020 for patients with severe allergic and atopic diseases and ANB019 for patients with GPP and PPP;

• the likelihood that the clinical data generated in any study we are performing or plan to perform in a non-U.S. jurisdiction will be subsequently accepted by the FDA and its foreign regulatory authorities outside of the jurisdiction where the study was being performed;

• the timing and ability of our collaborators to develop and commercialize our partnered product candidates;

• the potential benefits and advantages of our product candidates and approaches versus those of our competitors;

• our ability to execute on our strategy, including advancing our lead product candidates, identifying emerging opportunities in key therapeutic areas, continuing to expand our wholly-owned pipeline and retaining rights to strategic products in key commercial markets;

• our ability to obtain funding for our operations, including funding necessary to complete further development and commercialization of our product candidates;

• the timing of and our ability to obtain and maintain regulatory approvals for ANB020 and ANB019 and our other product candidates;

• our ability to develop our product candidates;

• the rate and degree of market acceptance and clinical utility of any approved product candidates;

• the size and growth potential of the markets for any approved product candidates, and our ability to serve those markets;

• our commercialization, marketing and manufacturing capabilities and strategy;

• our expectations regarding our ability to obtain and maintain intellectual property protection for our product candidates;

• regulatory developments in the United States, the United Kingdom, Australia and other foreign countries;

• the success of competing therapies that are or may become available;

• our ability to attract and retain key scientific or management personnel;

• our use of the net proceeds from this offering;

• our ability to identify additional products or product candidates with significant commercial potential that are consistent with our commercial objectives; and

• our estimates regarding expenses, future revenue, capital requirements and needs for additional financing.

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These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described or incorporated by reference in “Risk Factors” and elsewhere in this prospectus. Moreover, we operate in a competitive and rapidly changing environment, and new risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee that the future results, levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or occur. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this prospectus to conform these statements to actual results or to changes in our expectations, except as required by law.

You should read this prospectus, the documents incorporated by reference into this prospectus and the documents that we reference in this prospectus and have filed with the SEC as exhibits to the registration statement of which this prospectus is a part with the understanding that our actual future results, levels of activity, performance, and events and circumstances may be materially different from what we expect.

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MARKET AND INDUSTRY DATA

Unless otherwise indicated, information contained in or incorporated by reference into this prospectus concerning our industry and the markets in which we operate, including our general expectations and market position, market opportunity, and market size, is based on information from various sources and on assumptions that we have made that are based on those data and other similar sources and on our knowledge of the markets for our products. This information involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. While we believe the market position, market opportunity and market size information included in or incorporated by reference into this prospectus is generally reliable, such information is inherently imprecise. In addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate is necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Risk Factors” and in the documents incorporated by reference into this prospectus. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

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USE OF PROCEEDS

We estimate that the net proceeds from our sale of 3,000,000 shares of common stock in this offering at an assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, will be approximately $98.6 million, or $113.4 million if the underwriters exercise their option to purchase additional shares in full.

A $1.00 increase (decrease) in the assumed public offering price would increase (decrease) the net proceeds to us from this offering by $2.8 million, assuming the number of shares offered by us, remains the same, and after deducting the estimated underwriting discounts and commissions. Similarly, each increase or decrease of one million in the number of shares of common stock offered by us would increase (decrease) the net proceeds that we receive from this offering by $32.9 million, assuming that the assumed public offering price remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

We currently intend to use the net proceeds we receive from this offering, together with our existing cash, cash equivalents and investments, to fund research and development activities for our clinical development programs, including, but not limited to, our ongoing and planned clinical trials for ANB020 and ANB019, including related manufacturing costs, and our ongoing preclinical, discovery and research programs, and for working capital and other general corporate purposes.

Based on our planned use of the net proceeds, we estimate such funds, together with our existing cash, cash equivalents and investments, will be sufficient for us to fund our operating expenses and capital expenditure requirements through at least the next 24 months.

The expected use of the net proceeds from this offering represents our intentions based upon our current plans and business conditions. As of the date of this prospectus, we cannot predict with any certainty all of the particular uses for the net proceeds or the amounts that we will actually spend on the uses set forth above. We may use a portion of the net proceeds for the acquisition of, or investment in, technologies, solutions or businesses that complement our business, although we have no present commitments or agreements to do so.

The amounts and timing of our clinical expenditures and the extent of clinical development may vary significantly depending on numerous factors, including the status, results and timing of our current and planned preclinical studies and clinical trials, product approval process with the FDA and other regulatory agencies, our current collaborations and any new collaborations we may enter into with third parties and any unforeseen cash needs. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering.

The expected net proceeds of this offering will not be sufficient for us to fund any of our product candidates through regulatory approval, and we will need to raise substantial additional capital to complete the development and commercialization of our product candidates.

Pending their use as described above, we intend to invest the net proceeds from this offering in short term and long-term, investment-grade interest-bearing securities such as money market accounts, certificates of deposit, commercial paper and guaranteed obligations of the U.S. government.

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MARKET PRICE OF OUR COMMON STOCK

Our common stock has been listed on The NASDAQ Global Select Market under the symbol “ANAB” since January 25, 2017. Prior to that date, there was no public trading market for our common stock. The following table sets forth for the periods indicated the high and low sale prices per share of our common stock as reported on The NASDAQ Global Select Market for the periods indicated:

	High		Low
Fiscal Year 2017
First Quarter (beginning January 25, 2017)	$	29.96	$	15.17
Second Quarter	$	28.40	$	18.15
Third Quarter	$	37.62	$	20.12
Fourth Quarter (through October 9, 2017)	$	36.31	$	34.56

On October 9, 2017, the last reported sale price of our common stock on The NASDAQ Global Select Market was $35.00 per share. As of June 30, 2017, we had 95 registered holders of record of our common stock. The actual number of stockholders is greater than this number of record holders and includes stockholders who are beneficial owners but whose shares are held in street name by brokers and other nominees.

DIVIDEND POLICY

We have never declared or paid cash dividends on our common stock. We currently intend to retain all available funds and any future earnings for use in the operation of our business and do not anticipate paying any dividends on our common stock in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors and will depend on our financial condition, operating results, capital requirements, general business conditions and other factors that our board of directors may deem relevant. In addition, under the terms of our current credit facility, we are prohibited from paying cash dividends without the consent of Silicon Valley Bank.

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CAPITALIZATION

The following table sets forth our cash, cash equivalents and short-term investments and capitalization as of June 30, 2017 on:

• an actual basis; and

• an as adjusted basis, giving effect to the sale of 3,000,000 shares of common stock by us in this offering, based on an assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.

The as adjusted information set forth in the table below is illustrative only and will be adjusted based on the actual public offering price and other terms of this offering determined at pricing.

You should read this table together with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our audited and unaudited consolidated financial statements and related notes incorporated by reference into this prospectus.

	As of June 30, 2017 (unaudited)
(in thousands, except share and par value data)	Actual			As Adjusted(1)
Cash, cash equivalents and short-term investments	$	106,359		$	205,002
Notes payable, net of current portion	$	10,987		$	10,987
Deferred rent, net of current portion		168			168
Stockholders’ equity:
Preferred Stock, $0.001 par value; 10,000,000 shares authorized, no shares issued or outstanding, actual and as adjusted		—			—
Common stock, $0.001 par value; 500,000,000 shares authorized, 20,289,907 shares issued and outstanding, actual; 500,000,000 shares authorized, 23,289,907 shares issued and outstanding, as adjusted		20			23
Additional paid in capital		178,297			276,937
Accumulated other comprehensive loss Accumulated deficit		(59 (69,083	)  )		(59 (69,083	)  )
Total stockholders’ equity		109,175			207,818
Total capitalization	$	120,330		$	218,973

(1) Each $1.00 increase (decrease) in the assumed offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, would increase (decrease) each of our as adjusted cash, cash equivalents and short-term investments, additional paid-in capital, total stockholders’ equity and total capitalization by approximately $2.8 million, assuming that the number of shares offered by us remains the same and after deducting estimated underwriting discounts and commissions. Similarly, each increase (decrease) of one million shares in the number of shares offered by us would increase (decrease) each of our as adjusted cash, cash equivalents and short-term investments, additional paid-in capital, total stockholders’ equity and total capitalization by approximately $32.9 million, assuming the assumed offering price remains the same and after deducting the estimated underwriting discounts and commissions.

The number of shares of our common stock to be outstanding after this offering is based on 20,289,907 shares of our common stock outstanding as of June 30, 2017, and excludes:

• 2,643,180 shares of common stock issuable upon the exercise of options outstanding as of June 30, 2017, with a weighted-average exercise price of $10.62 per share;

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• 96,965 shares of common stock issuable upon the exercise of options granted after June 30, 2017, with a weighted-average exercise price of $26.77 per share;

• 198,009 shares of our common stock issuable upon exercise of warrants for shares of common stock that were outstanding as of June 30, 2017, with an exercise price of $4.55 per share; and

• 1,462,014 shares of common stock reserved for future issuance under our stock-based compensation plans, consisting of (a) 1,244,014 shares of common stock reserved for future issuance under our 2017 Equity Incentive Plan and (b) 218,000 shares of common stock reserved for future issuance under our 2017 Employee Stock Purchase Plan. Our 2017 Equity Incentive Plan and 2017 Employee Stock Purchase Plan also provide for automatic annual increases in the number of shares reserved under the plans each year, as more fully described in the section “Executive Compensation—Employee Benefit and Stock Plans” of our Quarterly Report on Form 10-Q for the period ended June 30, 2017 and our Annual Report on Form 10-K for the year ended December 31, 2016.

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DILUTION

If you invest in our common stock, your interest will be diluted to the extent of the difference between the amount per share paid by purchasers of shares of common stock in this offering and the as adjusted net tangible book value per share of common stock immediately after this offering.

As of June 30, 2017, our net tangible book value was approximately $109.2 million, or $5.38 per share of common stock. Our net tangible book value per share represents the amount of our total tangible assets reduced by the amount of our total liabilities and divided by the total number of shares of our common stock outstanding as of June 30, 2017.

After giving effect to our sale in this offering of 3,000,000 shares of our common stock at an assumed offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us, our net tangible book value as of June 30, 2017 would have been approximately $207.8 million, or $8.92 per share of common stock. This represents an immediate increase in net tangible book value of $3.54 per share to our existing stockholders and an immediate dilution of $26.08 per share to investors purchasing shares in this offering, as follows:

Assumed offering price per share			$	35.00
Net tangible book value per share as of June 30, 2017	$	5.38
Increase in net tangible book value per share attributable to new investors		3.54
As adjusted net tangible book value per share after this offering			$	8.92
Dilution per share to investors in this offering			$	26.08

A $1.00 increase (decrease) in the assumed public offering price of $35.00 per share, the last reported sale price of our common stock on The NASDAQ Global Select Market on October 9, 2017, would increase (decrease) our net tangible book value, as adjusted to give effect to this offering, by $0.12 per share and the dilution in as adjusted net tangible book value per share to new investors in this offering by $0.88 per share, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same, and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Similarly, each increase of one million shares in the number of shares offered by us in this offering would increase our as adjusted net tangible book value per share, and decrease the dilution per share to investors in this offering, by $0.99 per share. Each decrease of one million shares in the number of shares offered by us would decrease our as adjusted net tangible book value per share, and increase the dilution per share to investors in this offering, by $1.07 per share.

If the underwriters exercise their option in full to purchase additional shares, the net tangible book value per share of our common stock after giving effect to this offering would be $9.38 per share, and the dilution in net tangible book value per share to investors in this offering would be $25.62 per share.

The number of shares of our common stock to be outstanding after this offering is based on 20,289,907 shares of our common stock outstanding as of June 30, 2017, and excludes:

• 2,643,180 shares of common stock issuable upon the exercise of options outstanding as of June 30, 2017, with a weighted-average exercise price of $10.62 per share;

• 96,965 shares of common stock issuable upon the exercise of options granted after June 30, 2017, with a weighted-average exercise price of $26.77 per share;

• 198,009 shares of our common stock issuable upon exercise of warrants for shares of common stock that were outstanding as of June 30, 2017, with an exercise price of $4.55 per share; and

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• 1,462,014 shares of common stock reserved for future issuance under our stock-based compensation plans, consisting of (a) 1,244,014 shares of common stock reserved for future issuance under our 2017 Equity Incentive Plan and (b) 218,000 shares of common stock reserved for future issuance under our 2017 Employee Stock Purchase Plan. Our 2017 Equity Incentive Plan and 2017 Employee Stock Purchase Plan also provide for automatic annual increases in the number of shares reserved under the plans each year, as more fully described in the section “Executive Compensation—Employee Benefit and Stock Plans” of our Quarterly Report on Form 10-Q for the period ended June 30, 2017 and our Annual Report on Form 10-K for the year ended December 31, 2016.

To the extent that options or warrants outstanding as of June 30, 2017 have been or may be exercised, or we issue new options or warrants, investors purchasing our common stock in this offering may experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS

We describe below transactions and series of similar transactions since January 1, 2014 to which we were a party or will be a party, in which:

• the amounts involved exceeded or will exceed $120,000; and

• any of our directors, executive officers or beneficial holders of more than 5% of any class of our capital stock, or any member of the immediate family of the foregoing persons, had or will have a direct or indirect material interest.

Other than as described below, there have not been, nor are there any currently proposed, transactions or series of similar transactions to which we have been or will be a party other than compensation arrangements, which are described where required under the section entitled “Executive Compensation” in our Annual Report on Form 10-K for the year ended December 31, 2016.

Equity Financings

Series C-1 Preferred Stock Financing

In April 2014, we issued an aggregate of 474,001 shares of our Series C-1 convertible preferred stock at a purchase price of $4.55 per share, in exchange for the cancellation of secured convertible promissory notes originally issued in July 2013, which as of April 2014 had an aggregate principal and unpaid interest of $2.2 million.

The following table summarizes the Series C-1 convertible preferred stock issued to our executive officers, members of our board of directors and persons who hold more than 5% of our outstanding capital stock:

Name of Stockholder	Shares of Series C-1 Convertible Preferred Stock		Total Purchase Price
Entities affiliated with Frazier Healthcare(1)		195,751	$	890,670
Novo A/S(2)		195,751	$	890,670
Alloy Ventures 2005, L.P.		77,320	$	351,810
Hamza Suria(3)		781	$	3,555

(1) Represents shares held by Frazier Healthcare V, L.P., an affiliate of Frazier Healthcare Ventures. Dr. Topper, a member of our Board of Directors, is a General Partner of Frazier Healthcare and may be deemed to have voting and investment power with respect to these shares.

(2) Dr. Aynechi, a former member of our board of directors, is employed as a Partner at Novo Ventures (US) Inc., which provides certain consultancy services to Novo A/S, and Dr. Aynechi has no beneficial ownership of or pecuniary interest in these shares.

(3) Mr. Suria is our President and Chief Executive Officer and is a member of our Board of Directors.

Each share of our Series C-1 convertible preferred stock converted automatically into one share of our common stock upon the closing of our initial public offering. The purchasers of our Series C-1 convertible preferred stock are entitled to specified registration rights, as described under “Description of Capital Stock—Registration Rights.”

Series D Preferred Stock Financing

In July 2015, we sold an aggregate of 5,490,973 shares of our Series D convertible preferred stock at a purchase price of $7.42 per share, for an aggregate cash purchase price of $40.8 million.

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The following table summarizes the Series D convertible preferred stock purchased by our executive officers, members of our board of directors and persons who hold more than 5% of our outstanding capital stock:

Name of Stockholder	Shares of Series D Convertible Preferred Stock		Total Purchase Price
Entities affiliated with Biotechnology Value Fund, L.P		1,010,600	$	7,503,111
HBM Healthcare Investments (Cayman) Ltd		942,835	$	6,999,999
Entities affiliated with Frazier Healthcare(1)		942,835	$	6,999,999
Novo A/S(2)		673,454	$	5,000,000
Nicholas B. Lydon, Ph.D., FRS(3)		67,345	$	499,999
Carol G. Gallagher, Pharm.D.(4)		21,439	$	159,174
Robert E. Hoffman(5)		6,734	$	49,999
Hamza Suria(6)		2,020	$	14,999
Marco Londei, M.D.(7)		2,020	$	14,999

(1) Consists of shares held by Frazier Healthcare VII, L.P. and Frazier Healthcare VII-A, L.P., both affiliates of Frazier Healthcare. Dr. Topper, a member of our Board of Directors, is a General Partner of Frazier Healthcare and may be deemed to have voting and investment power with respect to these shares.

(2) Dr. Aynechi, a former member of our board of directors, is employed as a Partner at Novo Ventures (US) Inc., which provides certain consultancy services to Novo A/S, and Dr. Aynechi has no beneficial ownership of or pecuniary interest in these shares.

(3) Dr. Lydon is a member of our Board of Directors.

(4) Dr. Gallagher is a member of our Board of Directors.

(5) Mr. Hoffman is our former Chief Financial Officer.

(6) Mr. Suria is our President and Chief Executive Officer and is a member of our Board of Directors.

(7) Dr. Londei is our Chief Medical Officer.

Each share of our Series D convertible preferred stock converted automatically into one share of our common stock upon the closing of our initial public offering. The purchasers of our Series D convertible preferred stock are entitled to specified registration rights, as described below under “Description of Capital Stock—Registration Rights.”

Participation in our Initial Public Offering

Certain of our principal stockholders and their affiliated entities, including stockholders affiliated with certain of our directors, purchased an aggregate of 1,316,666 shares of our common stock in our initial public offering on January 31, 2017 at the initial public offering price of $15.00 per share. The following table summarizes common stock purchased by members of our board of directors and entities who held more than 5% of our outstanding capital stock at the time of the purchase:

Name	Number of Purchased Shares		Aggregate Purchase Price
Entities affiliated with Biotechnology Value Fund(1)		850,000	$	12,750,000
Entities affiliated with Frazier Healthcare(2)		400,000	$	6,000,000
Novo A/S		50,000	$	750,000
Nicholas B. Lydon, Ph.D.,FRS(3)		16,666	$	249,990
Total		1,316,666	$	19,749,990

(1) Consists of 414,373 shares purchased by Biotechnology Value Fund, L.P., 269,019 shares purchased by Biotechnology Value Fund II, L.P., 74,064 shares purchased by Biotechnology Value Trading Fund OS, L.P. and 92,544 shares purchased by MSI BVF SPV LLC.

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(2) Consists of 311,291 shares purchased by Frazier Healthcare VII, L.P and 88,709 shares purchased by Frazier Healthcare VII-A, L.P. Dr. Topper, a member of our Board of Directors, is a General Partner of Frazier Healthcare and may be deemed to have voting and investment power with respect to these shares.

(3) Dr. Lydon is a member of our Board of Directors.

Amended and Restated Investors’ Rights Agreement

We have entered into an amended and restated investors’ rights agreement with certain holders of our convertible preferred stock, including entities with which certain of our directors are affiliated. These stockholders are entitled to rights with respect to the registration of their shares. For a description of these registration rights, see “Description of Capital Stock—Registration Rights.”

Indemnification Agreements

We have entered into indemnification agreements with each of our directors and executive officers. The indemnification agreements, our restated certificate of incorporation and our restated bylaws will require us to indemnify our directors to the fullest extent not prohibited by Delaware law. Subject to certain limitations, our restated bylaws also require us to advance expenses incurred by our directors and officers.

Policies and Procedures for Related Party Transactions

We adopted a written related person transactions policy that our executive officers, directors, nominees for election as a director, beneficial owners of more than 5% of our common stock, and any members of the immediate family of and any entity affiliated with any of the foregoing persons, are not permitted to enter into a material related person transaction with us without the review and approval of our audit committee, or a committee composed solely of independent directors in the event it is inappropriate for our audit committee to review such transaction due to a conflict of interest. The policy provides that any request for us to enter into a transaction with an executive officer, director, nominee for election as a director, beneficial owner of more than 5% of our common stock or with any of their immediate family members or affiliates in which the amount involved exceeds $120,000 will be presented to our audit committee for review, consideration and approval. In approving or rejecting any such proposal, our audit committee will consider the relevant facts and circumstances available and deemed relevant to the audit committee, including, but not limited to, whether the transaction is on terms no less favorable than terms generally available to an unaffiliated third party under the same or similar circumstances and the extent of the related person’s interest in the transaction.

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PRINCIPAL STOCKHOLDERS

The following table sets forth certain information with respect to the beneficial ownership of our common stock at August 31, 2017, and as adjusted to reflect the sale of common stock in this offering, for:

• each of our directors;

• each of our named executive officers;

• all of our current directors and executive officers as a group; and

• each person, or group of affiliated persons, who beneficially owned more than 5% of our common stock.

We have determined beneficial ownership in accordance with the rules of the SEC, and the information is not necessarily indicative of beneficial ownership for any other purpose. Except as indicated by the footnotes below, we believe, based on information furnished to us, that the persons and entities named in the table below have sole voting and sole investment power with respect to all shares of common stock that they beneficially owned, subject to applicable community property laws.

Applicable percentage ownership is based on 20,469,570 shares of common stock outstanding as of August 31, 2017. For purposes of the table below, we have assumed that 3,000,000 shares of common stock will be issued by us in this public offering. In computing the number of shares of common stock beneficially owned by a person and the percentage ownership of that person, we deemed to be outstanding all shares of common stock subject to options held by that person or entity that are currently exercisable or that will become exercisable within 60 days of August 31, 2017. We did not deem these shares outstanding, however, for the purpose of computing the percentage ownership of any other person. Unless otherwise indicated, the address of each beneficial owner listed in the table below is c/o AnaptysBio, Inc., 10421 Pacific Center Court, Suite 200, San Diego, California 92121.

	Beneficial Ownership Prior to this Offering					Beneficial Ownership After this Offering
Name of Beneficial Owner	Number		Percent			Number		Percent
5% Stockholders:
Entities affiliated with Frazier Healthcare(1)		3,688,447		18.0	%		3,688,447		15.7	%
Novo Holdings A/S(2)		1,936,604		9.5			1,936,604		8.3
Alloy Ventures 2005, L.P.(3)		1,282,485		6.3			1,282,485		5.5
Entities affiliated with Biotechnology Value Fund, L.P.(4)		1,904,600		9.3			1,904,600		8.1
Directors and Named Executive Officers:
Hamza Suria(5)		562,330		2.7			562,330		2.3
Marco Londei, M.D.(6)		212,938		1.0			212,938		*
Matthew Moyle Ph.D.(7)		49,411		*			49,411		*
Carol G. Gallagher, Pharm.D.(8)		162,018		*			162,018		*
Nicholas B. Lydon, Ph.D., FRS(9)		335,118		1.6			335,118		1.4
Hollings Renton(10)		51,156		*			51,156		*
John Schmid(11)		42,337		*			42,337		*
James A. Schoeneck(12)		42,337		*			42,337		*
James N. Topper, M.D., Ph.D.(1)		3,688,447		18.0			3,688,447		15.7
J. Anthony Ware, M.D.(13)		1,588		*			1,588		*
All executive officers and directors as a group (11 persons)(14)		5,147,680		23.9			5,147,680		21.0

* Represents beneficial ownership of less than one percent.

(1) Based on Schedule 13-D filed by Frazier Healthcare V, L.P. on February 10, 2017. Consists of (a) 2,345,612 shares of common stock held directly by Frazier Healthcare V, L.P., (b) 1,045,031 shares of common stock held directly by Frazier Healthcare VII, L.P., (c) 297,804 shares of common stock held directly by Frazier Healthcare VII-A, L.P.. The general partner of Frazier Healthcare V, L.P. is FHM V, L.P., a Delaware

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limited partnership. The general partner of FHM V, L.P. is FHM V, LLC, a Delaware limited liability company. The general partner of Frazier Healthcare VII, L.P. and Frazier Healthcare VII-A, L.P. is FHM VII, L.P., a Delaware limited partnership. The general partner of FHM VII, L.P. is FHM VII, LLC, a Delaware limited liability company. Dr. Topper, a member of our Board of Directors, Alan Frazier, Nader Naini, Nathan Every and Patrick Heron are members of FHM V, LLC and FHM VII, LLC and may be deemed to share voting and investment power with respect to the shares held by FHM V, LLC and FHM VII, LLC. The address of Frazier Healthcare is 601 Union, Two Union Square, Suite 3200, Seattle WA 98101.

(2) Based on Form 4 filed by Novo Holdings A/S on August 21, 2017. Consists of (a) 1,936,604 shares of common stock held directly by Novo Holdings A/S. The board of directors of Novo A/S, which is currently comprised of Sten Scheibye, Gôran Ando, Jeppe Christiansen, Steen Riisgaard and Per Wold-Olsen, has shared voting and investment power with respect to these shares and may exercise such control only with the support of a majority of the board. As such, no individual member of the board is deemed to hold any beneficiary ownership in these shares. The address of Novo A/S is Tuborg Havnevej 19, 2900 Hellerup, Denmark.

(3) Consists of 1,282,485 shares of common stock held directly by Alloy Ventures 2005, L.P. The general partner of Alloy Ventures 2005, L.P. is Alloy Ventures 2005, LLC. The managing members of Alloy Ventures 2005, LLC are Craig Taylor, Doug Kelly John Shoch, Dan Rubin and Tony Di Bona.

(4) Based on Schedule 13-G filed by Biotechnology Value Fund L.P. on January 26, 2017. Consists of (a) 907,116 shares of common stock held directly by Biotechnology Value Fund, L.P., (b) 551,019 shares of common stock directly by Biotechnology Value Fund II, L.P., (c) 74,064 shares of common stock held directly by Trading Fund OS and (d) 372,401 shares of common stock held directly in the Partners Managed Accounts.

(5) Consists of (a) 4,998 shares of common stock held directly by Mr. Suria and (b) 557,332 shares of common stock issuable to Mr. Suria upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 102,499 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

(6) Consists of (a) 2,020 shares of common stock held directly by Dr. Londei and (b) 210,918 shares of common stock issuable to Dr. Londei upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 40,241 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

(7) Mr. Moyle resigned as our Chief Scientific Officer effective July 21, 2017. Consists of (a) 30,000 shares of common stock held directly by Mr. Moyle and (b) 19,411 shares of common stock issuable to Mr. Moyle upon the exercise of stock options that are exercisable within 60 days of August 31, 2017.

(8) Consists of (a) 64,296 shares of common stock held directly by Dr. Gallagher and (b) 97,722 shares of common stock issuable to Dr. Gallagher upon the exercise of stock options that are exercisable within 60 days of August 31, 2017.

(9) Consists of (a) 287,623 shares of common stock held directly by Dr. Lydon, (b) 16,483 shares of common stock issuable upon the exercise of a warrant held directly by Dr. Lydon and (c) 31,012 shares of common stock issuable to Dr. Lydon upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 2,134 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

(10) Represents 51,156 shares of common stock issuable to Mr. Renton upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 11,652 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

(11) Represents 42,337 shares of common stock issuable to Mr. Schmid upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 12,275 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

(12) Represents 42,337 shares of common stock issuable to Mr. Schoeneck upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 15,288 shares were unvested but were early exercisable, as of 60 days after August 31, 2017.

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(13) Represents 1,588 shares of common stock issuable to Mr. Ware upon the exercise of stock options that are exercisable within 60 days of August 31, 2017.

(14) Includes shares beneficially owned by our executive officers and directors. Consists of (a) 4,077,384 shares of common stock, (b) 16,483 shares of common stock issuable upon the exercise of warrants and (b) 1,053,813 shares of common stock issuable upon the exercise of stock options that are exercisable within 60 days of August 31, 2017, of which 184,089 shares were unvested but early exercisable, as of 60 days after August 31, 2017.

The above table does not include Dominic G. Piscitelli, who commenced his employment with us as our Chief Financial Officer in January 2017. As of August 31, 2017, Mr. Piscitelli was granted options to purchase 245,241 shares of our common stock, none of which are exercisable within 60 days of August 31, 2017.

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DESCRIPTION OF CAPITAL STOCK

Our authorized capital stock consists of 500,000,000 shares of common stock, $0.001 par value per share, and 10,000,000 shares of undesignated preferred stock, $0.001 par value per share. The following description summarizes the most important terms of our capital stock. Because it is only a summary, it does not contain all the information that may be important to you. For a complete description, you should refer to our restated certificate of incorporation and restated bylaws, which are included as exhibits to the registration statement of which this prospectus forms a part, and to the applicable provisions of Delaware law.

As of June 30, 2017, there were 20,289,907 shares of our common stock issued, held by approximately 95 stockholders of record, and no shares of our preferred stock outstanding. Our board of directors is authorized, without stockholder approval, to issue additional shares of our capital stock.

Common Stock

Dividend Rights

Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends out of funds legally available if our board of directors, in its discretion, determines to issue dividends and then only at the times and in the amounts that our board of directors may determine. See “Dividend Policy” above.

Voting Rights

Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders. We have not provided for cumulative voting for the election of directors in our restated certificate of incorporation. Accordingly, pursuant to our restated certificate of incorporation, holders of a majority of the shares of our common stock can elect all of our directors. Our restated certificate of incorporation establishes a classified board of directors, divided into three classes with staggered three-year terms. Only one class of directors is elected at each annual meeting of our stockholders, with the other classes continuing for the remainder of their respective three-year terms.

No Preemptive or Similar Rights

Our common stock is not entitled to preemptive rights, and is not subject to conversion, redemption or sinking fund provisions.

Right to Receive Liquidation Distributions

Upon our liquidation, dissolution or winding-up, the assets legally available for distribution to our stockholders would be distributable ratably among the holders of our common stock and any participating preferred stock outstanding at that time, subject to prior satisfaction of all outstanding debt and liabilities and the preferential rights of and the payment of liquidation preferences, if any, on any outstanding shares of preferred stock.

Preferred Stock

Our board of directors is authorized, subject to limitations prescribed by Delaware law, to issue preferred stock in one or more series, to establish from time to time the number of shares to be included in each series and

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to fix the designation, powers, preferences and rights of the shares of each series and any of their qualifications, limitations or restrictions, in each case without further vote or action by our stockholders. Our board of directors can also increase or decrease the number of shares of any series of preferred stock, but not below the number of shares of that series then outstanding, without any further vote or action by our stockholders. Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of our common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in control of our company and might adversely affect the market price of our common stock and the voting and other rights of the holders of our common stock. We have no current plan to issue any shares of preferred stock.

Warrants

As of June 30, 2017, we had outstanding warrants to purchase an aggregate of 198,009 shares of our common stock, with an exercise price of $4.55 per share.

Options

As of June 30, 2017, we had outstanding options to purchase an aggregate of 2,643,180 shares of our common stock, with a weighted-average exercise price of $10.62. Subsequent to June 30, 2017, we granted stock options to purchase 96,965 shares of common stock, with a weighted-average exercise price of $26.77 per share.

Registration Rights

Pursuant to the terms of our Amended and Restated Investor Rights Agreement, the holders of approximately 9,240,026 shares of our common stock are entitled to rights with respect to the registration of these shares under the Securities Act, as described below. We refer to these shares collectively as registrable securities.

Demand Registration Rights

At any point, the holders of at least a majority of the then-outstanding registrable securities may make a written request to us for the registration of any of the registrable securities under the Securities Act. Within 30 days of such request, we are obligated to provide written notice of such request to all stockholders to file a registration statement under the Securities Act covering all registrable securities that the initiating holders requested to be registered and any additional registrable securities requested to be included in such registration by any other holders. We are only required to file two registration statements that are declared effective upon exercise of these demand registration rights. We may postpone taking action with respect to such filing not more than once during any 12-month period for a total period of not more than 60 days if our board of directors determines in its good faith judgment that it would be seriously detrimental to us and our stockholders for such registration statement to be effected at such time.

Form S-3 Registration Rights

Any holder of then-outstanding registrable securities can request that we register all or part of their shares on Form S-3 if we are eligible to file a registration statement on Form S-3 and if the aggregate price to the public of the shares offered is at least $2,000,000. The stockholders may only require us to effect two registration statements on Form S-3 in a 12-month period. We may postpone taking action with respect to such filing once during any 12-month period for a total cumulative period of not more than 90 days if our board of directors determines in its good faith judgment that the filing would be materially detrimental to us and our stockholders.

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Piggyback Registration Rights

In connection with this offering, holders of registrable securities were entitled to, and the necessary percentage of holders waived, their rights to notice of this offering and to include their registrable securities in this offering. If we register any of our securities for public sale in another offering, holders of registrable securities will have the right to include their shares in the registration statement. However, this right does not apply to a registration relating to employee benefit plans, a registration relating to a corporate reorganization or a registration of only common stock issuable upon conversion of debt securities that are also being registered. We have the right to terminate any registration we have initiated before the effective date of such registration, whether or not any holder has elected to include registrable securities in such registration. The underwriters of any underwritten offering will have the right to limit the number of shares registered by these holders if they determine in good faith that marketing factors require limitation, in which case the number of shares to be registered will be apportioned pro rata among these holders, according to the total amount of securities entitled to be included by each holder, or in a manner mutually agreed upon by the holders. However, in any underwriting not in connection with an initial public offering, the number of shares to be registered by these holders cannot be reduced below 30% of the total shares covered by the registration statement.

Expenses of Registration Rights

We generally will pay all expenses, other than underwriting discounts and commissions.

Expiration of Registration Rights

The registration rights described above will expire, with respect to any particular holder of these rights, on the earlier of the fifth anniversary of the closing of our initial public offering, a merger, consolidation, sale or disposition of our company or a sale by a holder of equity securities representing at least a majority of the voting power of our company, or when that holder can sell all of its registrable securities in a three-month period without restriction under Rule 144 of the Securities Act.

Anti-Takeover Provisions

The provisions of Delaware law, our restated certificate of incorporation and our restated bylaws could have the effect of delaying, deferring or discouraging another person from acquiring control of our company. These provisions, which are summarized below, may have the effect of discouraging takeover bids. They are also designed, in part, to encourage persons seeking to acquire control of us to negotiate first with our board of directors. We believe that the benefits of increased protection of our potential ability to negotiate with an unfriendly or unsolicited acquirer outweigh the disadvantages of discouraging a proposal to acquire us because negotiation of these proposals could result in an improvement of their terms.

Delaware Law

We are subject to the provisions of Section 203 of the Delaware General Corporation Law regulating corporate takeovers. In general, Section 203 prohibits a publicly-held Delaware corporation from engaging in a business combination with an interested stockholder for a period of three years following the date on which the person became an interested stockholder unless:

• Prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

• The interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the voting stock outstanding, but

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not the outstanding voting stock owned by the interested stockholder, (1) shares owned by persons who are directors and also officers and (2) shares owned by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

• At or subsequent to the date of the transaction, the business combination is approved by the board of directors of the corporation and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66.67% of the outstanding voting stock that is not owned by the interested stockholder.

Generally, a business combination includes a merger, asset or stock sale, or other transaction or series of transactions together resulting in a financial benefit to the interested stockholder. An interested stockholder is a person who, together with affiliates and associates, owns or, within three years prior to the determination of interested stockholder status, did own 15% or more of a corporation’s outstanding voting stock. We expect the existence of this provision to have an anti-takeover effect with respect to transactions our board of directors does not approve in advance. We also anticipate that Section 203 may also discourage attempts that might result in a premium over the market price for the shares of common stock held by stockholders.

Restated Certificate of Incorporation and Restated Bylaw Provisions

Our restated certificate of incorporation and our restated bylaws include a number of provisions that could deter hostile takeovers or delay or prevent changes in control of our company, including the following:

• Board of Directors Vacancies. Our restated certificate of incorporation and restated bylaws authorize only our board of directors to fill vacant directorships, including newly created seats. In addition, the number of directors constituting our board of directors is permitted to be set only by a resolution adopted by a majority vote of our entire board of directors. These provisions would prevent a stockholder from increasing the size of our board of directors and then gaining control of our board of directors by filling the resulting vacancies with its own nominees. This makes it more difficult to change the composition of our board of directors but promotes continuity of management.

• Classified Board. Our restated certificate of incorporation and restated bylaws provide that our board is classified into three classes of directors, each with staggered three-year terms. A third party may be discouraged from making a tender offer or otherwise attempting to obtain control of us as it is more difficult and time consuming for stockholders to replace a majority of the directors on a classified board of directors.

• Stockholder Action; Special Meetings of Stockholders. Our restated certificate of incorporation provides that our stockholders may not take action by written consent, but may only take action at annual or special meetings of our stockholders. As a result, a holder controlling a majority of our capital stock would not be able to amend our restated bylaws or remove directors without holding a meeting of our stockholders called in accordance with our restated bylaws. Further, our restated bylaws provide that special meetings of our stockholders may be called only by a majority of our board of directors, the chairman of our board of directors, our Chief Executive Officer or our President, thus prohibiting a stockholder from calling a special meeting. These provisions might delay the ability of our stockholders to force consideration of a proposal or for stockholders controlling a majority of our capital stock to take any action, including the removal of directors.

• Advance Notice Requirements for Stockholder Proposals and Director Nominations. Our restated bylaws provide advance notice procedures for stockholders seeking to bring business before our annual meeting of stockholders or to nominate candidates for election as directors at our annual meeting of stockholders. Our restated bylaws also specify certain requirements regarding the form and content of a stockholder’s notice. These provisions might preclude our stockholders from bringing matters before our annual meeting of stockholders or from making nominations for directors at our annual meeting of stockholders

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if the proper procedures are not followed. We expect that these provisions might also discourage or deter a potential acquirer from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company.

• No Cumulative Voting. The Delaware General Corporation Law provides that stockholders are not entitled to the right to cumulate votes in the election of directors unless a corporation’s certificate of incorporation provides otherwise. Our restated certificate of incorporation and restated bylaws do not provide for cumulative voting.

• Directors Removed Only for Cause. Our restated certificate of incorporation provides that stockholders may remove directors only for cause and only by the affirmative vote of the holders of at least two-thirds of our outstanding common stock.

• Amendment of Charter Provisions. Any amendment of the above provisions in our restated certificate of incorporation would require approval by holders of at least two-thirds of our outstanding common stock.

• Issuance of Undesignated Preferred Stock. Our board of directors has the authority, without further action by the stockholders, to issue up to 10,000,000 shares of undesignated preferred stock with rights and preferences, including voting rights, designated from time to time by our board of directors. The existence of authorized but unissued shares of preferred stock would enable our board of directors to render more difficult or to discourage an attempt to obtain control of us by merger, tender offer, proxy contest or other means.

• Choice of Forum. Our restated certificate of incorporation provides that the Court of Chancery of the State of Delaware will be the exclusive forum for any derivative action or proceeding brought on our behalf; any action asserting a breach of fiduciary duty; any action asserting a claim against us arising pursuant to the Delaware General Corporation Law, our restated certificate of incorporation or our restated bylaws; or any action asserting a claim against us that is governed by the internal affairs doctrine.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer and Trust Company, LLC. The transfer agent’s address is 6201 15th Avenue, Brooklyn, New York 11219, and its telephone number is (800) 937-5449.

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MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS

This section summarizes the material U.S. federal income tax considerations relating to the acquisition, ownership and disposition of our common stock acquired in this offering by “non-U.S. holders” (as defined below). This summary does not provide a complete analysis of all potential U.S. federal income tax considerations relating thereto. The information provided below is based upon provisions of the Internal Revenue Code of 1986, as amended, or the Code, Treasury regulations promulgated thereunder, administrative rulings and judicial decisions currently in effect. These authorities may change at any time, possibly retroactively, or the Internal Revenue Service, or IRS, might interpret the existing authorities differently. In either case, the tax considerations of owning or disposing of our common stock could differ from those described below. As a result, we cannot assure you that the tax consequences described in this discussion will not be challenged by the IRS or will be sustained by a court if challenged by the IRS.

This summary does not address the tax considerations arising under the laws of any non-U.S., state or local jurisdiction, or under U.S. federal gift and estate tax laws, except to the limited extent provided below. In addition, this discussion does not address tax considerations applicable to an investor’s particular circumstances or to investors that may be subject to special tax rules, including, without limitation:

• banks, insurance companies or other financial institutions;

• partnerships or other entities treated as partnerships or pass-through entities for U.S. federal tax purposes (or investors in such entities);

• corporations that accumulate earnings to avoid U.S. federal income tax;

• persons subject to the alternative minimum tax or the Medicare contribution tax on net investment income;

• tax-exempt organizations or tax-qualified retirement plans;

• controlled foreign corporations or passive foreign investment companies;

• persons who acquired our common stock as compensation for services;

• dealers in securities or currencies;

• traders in securities that elect to use a mark-to-market method of accounting for their securities holdings;

• persons that own, or are deemed to own, more than 5% of our capital stock (except to the extent specifically set forth below);

• certain former citizens or long-term residents of the United States;

• persons who hold our common stock as a position in a hedging transaction, “straddle,” “conversion transaction” or other risk reduction transaction;

• persons who do not hold our common stock as a capital asset within the meaning of Section 1221 of the Code (generally, for investment purposes); or

• persons deemed to sell our common stock under the constructive sale provisions of the Code.

In addition, if a partnership or entity classified as a partnership or other pass-through entity for U.S. federal income tax purposes is a beneficial owner of our common stock, the tax treatment of a partner in the partnership or an owner of the entity will depend upon the status of the partner or other owner and the activities of the partnership or other entity. Accordingly, this summary does not address tax considerations applicable to partnerships that hold our common stock, and partners in such partnerships should consult their tax advisors.

INVESTORS CONSIDERING THE PURCHASE OF OUR COMMON STOCK SHOULD CONSULT THEIR OWN TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME AND ESTATE TAX LAWS TO THEIR PARTICULAR SITUATIONS AND THE CONSEQUENCES OF FOREIGN, STATE OR LOCAL LAWS, AND TAX TREATIES.

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Non-U.S. Holder Defined

For purposes of this summary, a “non-U.S. holder” is any beneficial owner of our common stock, other than a partnership, that is not:

• an individual who is a citizen or resident of the United States;

• a corporation, or other entity taxable as a corporation for U.S. federal income tax purposes, created or organized under the laws of the United States, any state therein or the District of Columbia;

• a trust if it (i) is subject to the primary supervision of a U.S. court and one of more U.S. persons have authority to control all substantial decisions of the trust or (ii) has a valid election in effect under the applicable Treasury regulations to be treated as a U.S. person; or

• an estate whose income is subject to U.S. income tax regardless of source.

If you are a non-U.S. citizen who is an individual, you may, in some cases, be deemed to be a resident alien, as opposed to a nonresident alien, by virtue of being present in the United States for at least 31 days in the calendar year and for an aggregate of at least 183 days during a three-year period ending in the current calendar year. Generally, for this purpose, all the days present in the current year, one-third of the days present in the immediately preceding year, and one-sixth of the days present in the second preceding year are counted. Resident aliens are subject to U.S. federal income tax as if they were U.S. citizens. Such an individual is urged to consult his or her own tax advisor regarding the U.S. federal income tax consequences of the ownership or disposition of our common stock.

Dividends

We do not expect to declare or make any distributions on our common stock in the foreseeable future. If we do pay dividends on shares of our common stock, however, such distributions will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Distributions in excess of our current and accumulated earnings and profits will constitute a return of capital that is applied against and reduces, but not below zero, a non-U.S. holder’s adjusted tax basis in shares of our common stock. Any remaining excess will be treated as gain realized on the sale or other disposition of our common stock. See “—Sale of Common Stock.”

Any dividend paid to a non-U.S. holder on our common stock that is not effectively connected with a non-U.S. holder’s conduct of a trade or business in the United States will generally be subject to U.S. withholding tax at a 30% rate. The withholding tax might apply at a reduced rate, however, under the terms of an applicable income tax treaty between the United States and the non-U.S. holder’s country of residence. You should consult your tax advisors regarding your entitlement to benefits under a relevant income tax treaty. Generally, in order for us or our paying agent to withhold tax at a lower treaty rate, a non-U.S. holder must certify its entitlement to treaty benefits. A non-U.S. holder generally can meet this certification requirement by providing a Form W-8BEN or Form W-8BEN-E (or any successor of such forms) or appropriate substitute form to us or our paying agent. If the non-U.S. holder holds the stock through a financial institution or other agent acting on the holder’s behalf, the holder will be required to provide appropriate documentation to the agent. The holder’s agent will then be required to provide certification to us or our paying agent, either directly or through other intermediaries. If you are eligible for a reduced rate of U.S. federal withholding tax under an income tax treaty, you may obtain a refund or credit of any excess amounts withheld by filing an appropriate claim for a refund with the IRS in a timely manner.

Dividends received by a non-U.S. holder that are effectively connected with a U.S. trade or business conducted by the non-U.S. holder, and if required by an applicable income tax treaty between the United States and the non-U.S. holder’s country of residence, are attributable to a permanent establishment maintained by the

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non-U.S. holder in the United States, are not subject to U.S. withholding tax. To obtain this exemption, a non-U.S. holder must provide us or our paying agent with an IRS Form W-8ECI properly certifying such exemption. Such effectively connected dividends, although not subject to withholding tax, are taxed at the same graduated rates applicable to U.S. persons, net of certain deductions and credits. In addition to being taxed at graduated tax rates, dividends received by corporate non-U.S. holders that are effectively connected with a U.S. trade or business of the corporate non-U.S. holder may also be subject to a branch profits tax at a rate of 30% or such lower rate as may be specified by an applicable tax treaty.

See also the section below titled “—Foreign Account Tax Compliance Act” for additional withholding rules that may apply to dividends paid to certain foreign financial institutions or non-financial foreign entities.

Sale of Common Stock

Subject to the discussions below regarding Backup Withholding and Information Reporting and the Foreign Account Tax Compliance Act, non-U.S. holders will generally not be subject to U.S. federal income tax on any gains realized on the sale, exchange or other disposition of our common stock unless:

• the gain (i) is effectively connected with the conduct by the non-U.S. holder of a U.S. trade or business and (ii) if required by an applicable income tax treaty between the United States and the non-U.S. holder’s country of residence, is attributable to a permanent establishment maintained by the non-U.S. holder in the United States (in which case the special rules described below apply);

• the non-U.S. holder is an individual who is present in the United States for 183 days or more in the taxable year of the sale, exchange or other disposition of our common stock, and certain other requirements are met (in which case the gain would be subject to a flat 30% tax, or such reduced rate as may be specified by an applicable income tax treaty, which may be offset by U.S. source capital losses, even though the individual is not considered a resident of the United States); or

• the rules of the Foreign Investment in Real Property Tax Act, or FIRPTA, treat the gain as effectively connected with a U.S. trade or business.

The FIRPTA rules may apply to a sale, exchange or other disposition of our common stock if we are, or were within the shorter of the five-year period preceding the disposition and the non-U.S. holder’s holding period, a “U.S. real property holding corporation,” or USRPHC. In general, we would be a USRPHC if interests in U.S. real estate comprised at least half of the value of our business assets. We do not believe that we are a USRPHC and we do not anticipate becoming one in the future. Even if we become a USRPHC, gain realized by a Non U.S. Holder on a disposition of our common stock will not be subject to U.S. federal income tax so long as (1) the Non U.S. Holder owned, directly, indirectly or constructively, no more than five percent of our common stock at all times within the shorter of (i) the five year period preceding the disposition or (ii) the holder’s holding period and (2) our common stock is regularly traded on an established securities market.

If any gain from the sale, exchange or other disposition of our common stock, (i) is effectively connected with a U.S. trade or business conducted by a non-U.S. holder and (ii) if required by an applicable income tax treaty between the United States and the non-U.S. holder’s country of residence, is attributable to a permanent establishment maintained by such non-U.S. holder in the United States, then the gain generally will be subject to U.S. federal income tax at the same graduated rates applicable to U.S. persons, net of certain deductions and credits. If the non-U.S. holder is a corporation, under certain circumstances, that portion of its earnings and profits that is effectively connected with its U.S. trade or business, subject to certain adjustments, generally would be subject also to a “branch profits tax.” The branch profits tax rate is 30%, although an applicable income tax treaty between the United States and the non-U.S. holder’s country of residence might provide for a lower rate.

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U.S. Federal Estate Tax

The estates of nonresident alien individuals generally are subject to U.S. federal estate tax on property with a U.S. situs. Because we are a U.S. corporation, our common stock will be U.S. situs property and therefore will be included in the taxable estate of a nonresident alien decedent, unless an applicable estate tax treaty between the United States and the decedent’s country of residence provides otherwise. The terms “resident” and “nonresident” are defined differently for U.S. federal estate tax purposes than for U.S. federal income tax purposes. Investors are urged to consult their own tax advisors regarding the U.S. federal estate tax consequences of the ownership or disposition of our common stock.

Backup Withholding and Information Reporting

The Code and the Treasury regulations require those who make specified payments to report the payments to the IRS. Among the specified payments are dividends and proceeds paid by brokers to their customers. The required information returns enable the IRS to determine whether the recipient properly included the payments in income. This reporting regime is reinforced by “backup withholding” rules. These rules require the payors to withhold tax from payments subject to information reporting if the recipient fails to cooperate with the reporting regime by failing to provide his taxpayer identification number to the payor, furnishing an incorrect identification number, or failing to report interest or dividends on his returns. The backup withholding tax rate is currently 28%. The backup withholding rules do not apply to payments to corporations, whether domestic or foreign, provided they establish such exemption.

Payments to non-U.S. holders of dividends on common stock generally will not be subject to backup withholding, and payments of proceeds made to non-U.S. holders by a broker upon a sale of common stock will not be subject to information reporting or backup withholding, in each case so long as the non-U.S. holder certifies its nonresident status (and we or our paying agent do not have actual knowledge or reason to know the holder is a U.S. person or that the conditions of any other exemption are not, in fact, satisfied) or otherwise establishes an exemption. The certification procedures to claim treaty benefits described under “—Dividends” will generally satisfy the certification requirements necessary to avoid the backup withholding tax. We must report annually to the IRS any dividends paid to each non-U.S. holder and the tax withheld, if any, with respect to these dividends. Copies of these reports may be made available to tax authorities in the country where the non-U.S. holder resides.

Under the Treasury regulations, the payment of proceeds from the disposition of shares of our common stock by a non-U.S. holder made to or through a U.S. office of a broker generally will be subject to information reporting and backup withholding unless the beneficial owner certifies, under penalties of perjury, among other things, its status as a non-U.S. holder (and the broker does not have actual knowledge or reason to know the holder is a U.S. person) or otherwise establishes an exemption. The payment of proceeds from the disposition of shares of our common stock by a non-U.S. holder made to or through a non-U.S. office of a broker generally will not be subject to backup withholding and information reporting, except as noted below. Information reporting, but not backup withholding, will apply to a payment of proceeds, even if that payment is made outside of the United States, if you sell our common stock through a non-U.S. office of a broker that is:

• a U.S. person (including a foreign branch or office of such person);

• a “controlled foreign corporation” for U.S. federal income tax purposes;

• a foreign person 50% or more of whose gross income from certain periods is effectively connected with a U.S. trade or business; or

• a foreign partnership if at any time during its tax year (a) one or more of its partners are U.S. persons who, in the aggregate, hold more than 50% of the income or capital interests of the partnership or (b) the foreign partnership is engaged in a U.S. trade or business;

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unless the broker has documentary evidence that the beneficial owner is a non-U.S. holder and certain other conditions are satisfied, or the beneficial owner otherwise establishes an exemption (and the broker has no actual knowledge or reason to know to the contrary).

Backup withholding is not an additional tax. Any amounts withheld from a payment to a holder of common stock under the backup withholding rules can be credited against any U.S. federal income tax liability of the holder and may entitle the holder to a refund, provided that the required information is furnished to the IRS in a timely manner.

Foreign Account Tax Compliance Act

A U.S. federal withholding tax of 30% may apply to dividends and the gross proceeds of a disposition of our common stock paid to a foreign financial institution (as specifically defined by the applicable rules) unless such institution enters into an agreement with the U.S. government to withhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity holders of such institution, as well as certain account holders that are foreign entities with U.S. owners). This U.S. federal withholding tax of 30% will also apply to dividends and the gross proceeds of a disposition of our common stock paid to a non-financial foreign entity unless such entity provides the withholding agent with either a certification that it does not have any substantial direct or indirect U.S. owners or provides information regarding direct and indirect U.S. owners of the entity. The 30% federal withholding tax described in this paragraph cannot be reduced under an income tax treaty with the United States or by providing an IRS Form W-8BEN or similar documentation. The withholding tax described above will not apply if the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from the rules. Under certain circumstances, a non-U.S. holder might be eligible for refunds or credits of such taxes. Holders should consult with their own tax advisors regarding the possible implications of the withholding described herein. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing FATCA may be subject to different rules.

The withholding provisions described above generally will apply to proceeds from a sale or other disposition of common stock if such sale or other disposition occurs on or after January 1, 2019 and currently apply to payments of dividends on our common stock.

EACH PROSPECTIVE INVESTOR SHOULD CONSULT ITS OWN TAX ADVISOR REGARDING THE PARTICULAR U.S. FEDERAL, STATE, LOCAL AND FOREIGN TAX CONSEQUENCES OF PURCHASING, HOLDING AND DISPOSING OF OUR COMMON STOCK, INCLUDING THE CONSEQUENCES OF ANY PROPOSED CHANGE IN APPLICABLE LAWS.

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UNDERWRITING

Under the terms and subject to the conditions contained in an underwriting agreement dated                 , we have agreed to sell to the underwriters named below, for whom Credit Suisse Securities (USA) LLC, Jefferies LLC and Stifel, Nicolaus & Company, Incorporated are acting as representatives, the following respective numbers of shares of common stock:

Underwriter	Number of Shares
Credit Suisse Securities (USA) LLC
Jefferies LLC
Stifel, Nicolaus & Company, Incorporated
Total		3,000,000

The underwriting agreement provides that the underwriters are obligated to purchase all the shares of common stock in the offering if any are purchased, other than those shares covered by the option to purchase additional shares described below. The underwriting agreement also provides that if an underwriter defaults the purchase commitments of non-defaulting underwriters may be increased or the offering may be terminated.

We have granted to the underwriters a 30-day option to purchase on a pro rata basis up to 450,000 additional shares at the public offering price less the underwriting discounts and commissions.

The underwriters propose to offer the shares of common stock initially at the public offering price on the cover page of this prospectus and to selling group members at that price less a selling concession of $        per share. The underwriters and selling group members may allow a discount of $        per share on sales to other broker/dealers. After the public offering the underwriters may change the public offering price and concession and discount to broker/dealers.

The following table summarizes the compensation we will pay:

	Per Share		Total
	Without Option to Purchase Additional Shares	With Option to Purchase Additional Shares	Without Option to Purchase Additional Shares	With Option to Purchase Additional Shares
Underwriting Discounts and Commissions paid by us	$	$	$	$

We estimate that our out of pocket expenses for this offering will be approximately $407,327. We have also agreed to reimburse the underwriters for up to $35,000 for their FINRA counsel fee. In accordance with FINRA Rule 5110, this reimbursed fee is deemed underwriting compensation for this offering. In addition, the underwriters have agreed to reimburse us for certain expenses.

We and our executive officers and directors (other than Dr. Lydon) have agreed with the underwriters that, for a period of 90 days after the date of this prospectus, and Dr. Lydon and entities affiliated with Frazier Healthcare have agreed with the underwriters that, for a period of 60 days after the date of this prospectus, subject to certain exceptions, we and they will not (1) offer, sell, pledge, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition), directly or indirectly, including the filing (or participation in the filing) with the SEC of a registration statement under the Securities Act to register, any shares of our common stock or any securities convertible into or exercisable or exchangeable for our common stock or warrants or other rights to acquire shares of our common stock of which such officer, director or holder is now, or may in the future become, the beneficial owner (within the meaning of Rule 13d-3 under the Exchange Act), or (2) enter into any

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swap or other derivatives transaction that transfers to another, in whole or in part, directly or indirectly, any of the economic benefits or risks of ownership of such common stock, securities, warrants or other rights to acquire common stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of common stock or other securities, in cash or otherwise, or (3) publicly disclose the intention to enter into any transaction described in clause (1) or (2) above, except with the prior written consent of Credit Suisse Securities (USA) LLC.

The restrictions on our executive officers and directors and their affiliates above do not apply to the following, subject to certain limitations set forth in the lock-up agreements:

• transfers of securities as a bona fide gift;

• transfers or dispositions of securities to any trust for the direct or indirect benefit of the lock-up signatory or any member of the immediate family of the lock-up signatory;

• transfers of securities to affiliates;

• transfers of securities by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the lock-up signatory;

• transfers or dispositions of shares of our common stock or securities convertible or exchangeable into shares of our common stock acquired in open market purchases after the closing of this offering;

• entry into any trading plan established pursuant to Rule 10b5-1 under the Exchange Act;

• exercise of options, warrants or other rights to acquire shares of common stock in accordance with their terms pursuant to an employee benefit plan, option, warrant or other right;

• transfers pursuant to a court order or settlement agreement related to the distribution of assets in connection with the dissolution of a marriage or civil union;

• transfers to us pursuant to agreements under which we have the option to repurchase such shares or a right of first refusal with respect to transfers of such shares upon termination of service of the lock-up signatory;

• transfers by certain stockholders of shares purchased in this offering; or

• transfers of shares of our common stock or any security convertible into or exercisable or exchangeable for common stock pursuant to a liquidation, tender offer, merger, consolidation or similar transaction that results in all of our stockholders having the right to exchange their securities for cash, securities or other property.

We have agreed to indemnify the underwriters against liabilities under the Securities Act, or contribute to payments that the underwriters may be required to make in that respect.

Our common stock is listed on The NASDAQ Global Select Market under the symbol “ANAB.”

In connection with the offering the underwriters may engage in stabilizing transactions, over-allotment transactions, syndicate covering transactions and penalty bids and passive market making in accordance with Regulation M under the Securities Exchange Act of 1934, as amended, or the Exchange Act.

• Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum.

• Over-allotment involves sales by the underwriters of shares in excess of the number of shares the underwriters are obligated to purchase, which creates a syndicate short position. The short position may be either a covered short position or a naked short position. In a covered short position, the number of shares over-allotted by the underwriters is not greater than the number of additional shares that they have

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the option to purchase. In a naked short position, the number of shares involved is greater than the number of additional shares that they have the option to purchase. The underwriters may close out any covered short position by either exercising their option to purchase additional shares and/or purchasing shares in the open market.

• Syndicate covering transactions involve purchases of the common stock in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares to close out the short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which they may purchase additional shares through their option. If the underwriters sell more shares than could be covered by the option to purchase additional shares, a naked short position, the position can only be closed out by buying shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that there could be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase in the offering.

• Penalty bids permit the representatives to reclaim a selling concession from a syndicate member when the common stock originally sold by the syndicate member is purchased in a stabilizing or syndicate covering transaction to cover syndicate short positions.

• In passive market making, market makers in the common stock who are underwriters or prospective underwriters may, subject to limitations, make bids for or purchases of our common stock until the time, if any, at which a stabilizing bid is made.

These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of the common stock. As a result the price of our common stock may be higher than the price that might otherwise exist in the open market. These transactions may be effected on The NASDAQ Global Select Market or otherwise and, if commenced, may be discontinued at any time.

A prospectus in electronic format may be made available on the web sites maintained by one or more of the underwriters, or selling group members, if any, participating in this offering and one or more of the underwriters participating in this offering may distribute prospectuses electronically. The representatives may agree to allocate a number of shares to underwriters and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the underwriters and selling group members that will make internet distributions on the same basis as other allocations.

The underwriters and their respective affiliates are full-service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. Certain of the underwriters and their respective affiliates have, from time to time, performed, and may in the future perform, various financial advisory and investment banking services for us, for which they received or will receive customary fees and expenses.

In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. These investments and securities activities may involve securities and/or instruments of ours or our affiliates. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

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Selling Restrictions:

General

Other than in the United States, no action has been taken by us or the underwriters that would permit a public offering of the securities offered by this prospectus in any jurisdiction where action for that purpose is required. The securities offered by this prospectus may not be offered or sold, directly or indirectly, nor may this prospectus or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus. This prospectus does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus in any jurisdiction in which such an offer or a solicitation is unlawful.

Notice to Prospective Investors in Switzerland

This document is not intended to constitute an offer or solicitation to purchase or invest in the securities described herein. The securities may not be publicly offered, sold or advertised, directly or indirectly, in, into or from Switzerland and will not be listed on the SIX Swiss Exchange or on any other exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the securities constitutes a prospectus as such term is understood pursuant to article 652a or article 1156 of the Swiss Code of Obligations or a listing prospectus within the meaning of the listing rules of the SIX Swiss Exchange or any other regulated trading facility in Switzerland, and neither this document nor any other offering or marketing material relating to the securities may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, nor the Company nor the securities have been or will be filed with or approved by any Swiss regulatory authority. The securities are not subject to the supervision by any Swiss regulatory authority, e.g., the Swiss Financial Markets Supervisory Authority FINMA (FINMA), and investors in the securities will not benefit from protection or supervision by such authority.

Notice to Prospective Investors in the European Economic Area

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a Relevant Member State), each underwriter represents and agrees that with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State, it has not made and will not make an offer of securities which are the subject of the offering contemplated by this prospectus to the public in that Relevant Member State other than:

(a) to any legal entity which is a qualified investor as defined in the Prospectus Directive;

(b) to fewer than 100 or, if the Relevant Member State has implemented the relevant provision of the 2010 PD Amending Directive, 150, natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the representatives for any such offer; or

(c) in any other circumstances falling within Article 3(2) of the Prospectus Directive, provided that no such offer of securities shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive.

For the purposes of this provision, the expression an “offer to the public” in relation to any securities in any Relevant Member State means the communication in any form and by any means of sufficient information on the

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terms of the offer and the securities to be offered so as to enable an investor to decide to purchase or subscribe the securities, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State, the expression Prospectus Directive means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State), and includes any relevant implementing measure in the Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

Notice to Prospective Investors in the United Kingdom

Each of the underwriters severally represents warrants and agrees as follows:

(a) it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the Financial Services and Markets Act 2000 (FSMA) received by it in connection with the issue or sale of the securities in circumstances in which Section 21 of the FSMA does not apply to us; and

(b) it has complied with, and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to the securities in, from or otherwise involving the United Kingdom.

Notice to Canadian Residents

Resale Restrictions

The distribution of shares of common stock offered hereby in Canada is being made only in the provinces of Ontario, Quebec, Alberta and British Columbia on a private placement basis exempt from the requirement that we prepare and file a prospectus with the securities regulatory authorities in each province where trades of these securities are made. Any resale of the shares offered hereby in Canada must be made under applicable securities laws which may vary depending on the relevant jurisdiction, and which may require resales to be made under available statutory exemptions or under a discretionary exemption granted by the applicable Canadian securities regulatory authority. Purchasers are advised to seek legal advice prior to any resale of the shares.

Representations of Canadian Purchasers

By purchasing shares of common stock offered hereby in Canada and accepting delivery of a purchase confirmation, a purchaser is representing to us and the dealer from whom the purchase confirmation is received that:

• the purchaser is entitled under applicable provincial securities laws to purchase the shares without the benefit of a prospectus qualified under those securities laws as it is an “accredited investor” as defined under National Instrument 45-106—Prospectus Exemptions,

• the purchaser is a “permitted client” as defined in National Instrument 31-103—Registration Requirements, Exemptions and Ongoing Registrant Obligations,

• where required by law, the purchaser is purchasing as principal and not as agent, and

• the purchaser has reviewed the text above under Resale Restrictions.

Conflicts of Interest

Canadian purchasers are hereby notified that the underwriters are relying on the exemption set out in section 3A.3 or 3A.4, if applicable, of National Instrument 33-105—Underwriting Conflicts from having to provide certain conflict of interest disclosure in this document.

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Statutory Rights of Action

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if the offering memorandum (including any amendment thereto) such as this document contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser of these securities in Canada should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Enforcement of Legal Rights

All of our directors and officers as well as the experts named herein may be located outside of Canada and, as a result, it may not be possible for Canadian purchasers to effect service of process within Canada upon us or those persons. All or a substantial portion of our assets and the assets of those persons may be located outside of Canada and, as a result, it may not be possible to satisfy a judgment against us or those persons in Canada or to enforce a judgment obtained in Canadian courts against us or those persons outside of Canada.

Taxation and Eligibility for Investment

Canadian purchasers of shares of common stock offered hereby should consult their own legal and tax advisors with respect to the tax consequences of an investment in the shares in their particular circumstances and about the eligibility of the shares for investment by the purchaser under relevant Canadian legislation.

Notice to Prospective Investors in France

Neither this prospectus nor any other offering material relating to the securities described in this prospectus has been submitted to the clearance procedures of the Autorité des Marchés Financiers or of the competent authority of another member state of the European Economic Area and notified to the Autorité des Marchés Financiers. The securities have not been offered or sold and will not be offered or sold, directly or indirectly, to the public in France. Neither this prospectus nor any other offering material relating to the securities has been or will be:

• to any legal entity which is a qualified investor as defined in the Prospectus Directive;

• to fewer than 100 or, if the relevant member state has implemented the relevant provision of the 2010 PD Amending Directive, 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the relevant Dealer or Dealers nominated by us for any such offer; or

• in any other circumstances falling within Article 3(2) of the Prospectus Directive,

• released, issued, distributed or caused to be released, issued or distributed to the public in France; or

• used in connection with any offer for subscription or sale of the securities to the public in France.

Such offers, sales and distributions will be made in France only:

• to qualified investors (investisseurs qualifiés) and/or to a restricted circle of investors (cercle restreint d’investisseurs), in each case investing for their own account, all as defined in, and in accordance with articles L.411-2, D.411-1, D.411-2, D.734-1, D.744-1, D.754-1 and D.764-1 of the French Code monétaire et financier;

• to investment services providers authorized to engage in portfolio management on behalf of third parties; or

• in a transaction that, in accordance with article L.411-2-II-1° -or-2° -or 3° of the French Code monétaire et financier and article 211-2 of the General Regulations (Règlement Général) of the Autorité des Marchés Financiers, does not constitute a public offer (appel public à l’épargne).

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The securities may be resold directly or indirectly, only in compliance with articles L.411-1, L.411-2, L.412-1 and L.621-8 through L.621-8-3 of the French Code monétaire et financier.

Notice to Prospective Investors in the Republic of Italy

The offering of securities has not been registered with the Commissione Nazionale per le Società e la Borsa (“CONSOB”) pursuant to Italian securities legislation and, accordingly, no securities may be offered, sold or delivered, nor copies of this prospectus supplement, the accompanying prospectus or any other documents relating to the securities may not be distributed in Italy except:

(a) to “qualified investors”, as referred to in Article 100 of Legislative Decree No. 58 of 24 February 1998, as amended (the “Decree No. 58”) and defined in Article 26, paragraph 1, letter d) of CONSOB Regulation No. 16190 of 29 October 2007, as amended (“Regulation No. 16190”) pursuant to Article 34-ter, paragraph 1, letter. b) of CONSOB Regulation No. 11971 of 14 May 1999, as amended (“Regulation No. 11971”); or

(b) in any other circumstances where an express exemption from compliance with the offer restrictions applies, as provided under Decree No. 58 or Regulation No. 11971.

Any offer, sale or delivery of the securities or distribution of copies of this prospectus supplement, the accompanying prospectus or any other documents relating to the securities in the Republic of Italy must be:

(a) made by investment firms, banks or financial intermediaries permitted to conduct such activities in the Republic of Italy in accordance with Legislative Decree No. 385 of 1 September 1993, as amended (the “Banking Law”), Decree No. 58 and Regulation No. 16190 and any other applicable laws and regulations;

(b) in compliance with Article 129 of the Banking Law, and the implementing guidelines of the Bank of Italy, as amended; and

(c) in compliance with any other applicable notification requirement or limitation which may be imposed, from time to time, by CONSOB or the Bank of Italy or other competent authority.

Please note that, in accordance with Article 100-bis of Decree No. 58, where no exemption from the rules on public offerings applies, the subsequent distribution of the securities on the secondary market in Italy must be made in compliance with the public offer and the prospectus requirement rules provided under Decree No. 58 and Regulation No. 11971.

Furthermore, securities which are initially offered and placed in Italy or abroad to qualified investors only but in the following year are regularly (“sistematicamente”) distributed on the secondary market in Italy to non-qualified investors become subject to the public offer and the prospectus requirement rules provided under Decree No. 58 and Regulation No. 11971. Failure to comply with such rules may result in the sale of the securities being declared null and void and in the liability of the intermediary transferring the securities for any damages suffered by such non-qualified investors.

Notice to Prospective Investors in Germany

This prospectus does not constitute a Prospectus Directive-compliant prospectus in accordance with the German Securities Prospectus Act (Wertpapierprospektgesetz) and does therefore not allow any public offering in the Federal Republic of Germany (“Germany”) or any other Relevant Member State pursuant to § 17 and § 18 of the German Securities Prospectus Act. No action has been or will be taken in Germany that would permit a public offering of the securities, or distribution of a prospectus or any other offering material relating to the securities. In particular, no securities prospectus (Wertpapierprospekt) within the meaning of the German Securities Prospectus Act or any other applicable laws of Germany, has been or will be published within Germany, nor has this prospectus been filed with or approved by the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht) for publication within Germany.

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Each manager will represent, agree and undertake, (i) that it has not offered, sold or delivered and will not offer, sell or deliver the securities within Germany other than in accordance with the German Securities Prospectus Act (Wertpapierprospektgesetz) and any other applicable laws in Germany governing the issue, sale and offering of securities, and (ii) that it will distribute in Germany any offering material relating to the securities only under circumstances that will result in compliance with the applicable rules and regulations of Germany.

This prospectus is strictly for use of the person who has received it. It may not be forwarded to other persons or published in Germany.

Notice to Prospective Investors in the United Arab Emirates

The securities have not been, and are not being, publicly offered, sold, promoted or advertised in the United Arab Emirates (“U.A.E.”) other than in compliance with the laws of the U.A.E. Prospective investors in the Dubai International Financial Centre should have regard to the specific notice to prospective investors in the Dubai International Financial Centre set out above.

The information contained in this prospectus supplement and the accompanying prospectus does not constitute a public offer of securities in the U.A.E. in accordance with the Commercial Companies Law (Federal Law No. 8 of 1984 of the U.A.E., as amended) or otherwise and is not intended to be a public offer. This prospectus supplement and the accompanying prospectus have not been approved by or filed with the Central Bank of the United Arab Emirates, the Emirates Securities and Commodities Authority or the Dubai Financial Services Authority, or DFSA. If you do not understand the contents of this prospectus supplement or the accompanying prospectus, you should consult an authorized financial adviser. This prospectus supplement and the accompanying prospectus are provided for the benefit of the recipient only, and should not be delivered to, or relied on by, any other person.

Notice to Prospective Investors in the Dubai International Financial Centre

This document relates to an exempt offer in accordance with the Offered Securities Rules of the Dubai Financial Services Authority. This document is intended for distribution only to persons of a type specified in those rules. It must not be delivered to, or relied on by, any other person. The Dubai Financial Services Authority has no responsibility for reviewing or verifying any documents in connection with exempt offers. The Dubai Financial Services Authority has not approved this document nor taken steps to verify the information set out in it, and has no responsibility for it. The notes which are the subject of the offering contemplated by this offering memorandum may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the notes offered should conduct their own due diligence on the notes. If you do not understand the contents of this document you should consult an authorized financial advisor.

Notice to Prospective Investors in the Kingdom of Saudi Arabia

This prospectus may not be distributed in the Kingdom of Saudi Arabia except to such persons as are permitted under the Offers of Securities Regulations issued by the Capital Market Authority of Saudi Arabia (the “Capital Market Authority”). The Capital Market Authority does not make any representations as to the accuracy or completeness of this prospectus, and expressly disclaims any liability whatsoever for any loss arising from, or incurred in reliance upon, any part of this prospectus. Prospective purchasers of the securities offered hereby should conduct their own due diligence on the accuracy of the information relating to the securities. If a prospective purchaser does not understand the contents of this prospectus he or she should consult an authorised financial adviser. By accepting this prospectus and other information relating to the offering of the securities in the Kingdom of Saudi Arabia, each recipient represents that he is a “sophisticated investor”, as set out in the prospectus.

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Notice to Prospective Investors in Israel

This prospectus does not constitute a prospectus under the Israeli Securities Law, 5728-1968, and has not been filed with or approved by the Israel Securities Authority. In Israel, this prospectus is being distributed only to, and is directed only at, investors listed in the first addendum, or the Addendum, to the Israeli Securities Law, consisting primarily of joint investment in trust funds, provident funds, insurance companies, banks, portfolio managers, investment advisors, members of the Tel Aviv Stock Exchange, underwriters purchasing for their own account, venture capital funds, entities with equity in excess of NIS 50 million and qualified individuals, each as defined in the Addendum (as it may be amended from time to time), collectively referred to as qualified investors. Qualified investors may be required to submit written confirmation that they meet the criteria for one of the categories of investors set forth in the prospectus.

Notice to Prospective Investors in South Africa

Due to restrictions under the securities laws of South Africa, the securities are not offered, and the offer of our securities shall not be transferred, sold, renounced or delivered, in South Africa or to a person with an address in South Africa, unless one or other of the following exemptions applies:

(i) the offer, transfer, sale, renunciation or delivery is to duly registered banks, mutual banks, financial services provider, financial institution, the Public Investment Corporation (in each case registered as such in South Africa), a person who deals with securities in their ordinary course of business, or a wholly owned subsidiary of a bank, mutual bank, authorized services provider or financial institution, acting as agent in the capacity of an authorized portfolio manager for a pension fund (duly registered in South Africa), or as manager for a collective investment scheme(registered in South Africa); or

(ii) the contemplated acquisition cost of the securities, for any single addressee acting as principal is equal to or greater than R1,000,000.

This document does not, nor is it intended to, constitute an “offer to the public” (as that term is defined in the South African Companies Act, 2008 (the “SA Companies Act”) and does not, nor is it intended to, constitute a prospectus prepared and registered under the SA Companies Act. This document is not an “offer to the public” and must not be acted on or relied on by persons who do not fall within Section 96(1)(a) of the SA Companies Act (such persons being referred to as “relevant persons”). Any investment or investment activity to which this document relates is available only to relevant persons and will be engaged in only with relevant persons. A South African resident person or company or any non-South African company which is a subsidiary of a South African company is not permitted to acquire the securities unless such person has obtained exchange control approval to do so.

Notice to Prospective Investors in Hong Kong

The securities may not be offered or sold in Hong Kong by means of any document other than (i) to “professional investors” as defined in the Securities and Futures Ordinance (Cap.571) of Hong Kong and any rules made under that Ordinance, or (ii) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies Ordinance (Cap.32) of Hong Kong or which do not constitute an offer to the public within the meaning of that Ordinance. No advertisement, invitation or document relating to the depositary securities may be issued or may be in the possession of any person for the purpose of issue, whether in Hong Kong or elsewhere, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to depositary securities which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the Securities and Futures Ordinance and any rules made under that Ordinance.

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Notice to Prospective Investors in Singapore

This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of securities may not be circulated or distributed, nor may the securities be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than

(i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”), (ii) to a relevant person pursuant to Section 275(1), or any person pursuant to Section 275(1A), and in accordance with the conditions specified in Section 275, of the SFA, or

(ii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the securities are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

(a) a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or

(b) a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary of the trust is an individual who is an accredited investor, securities (as defined in Section 239(1) of the SFA) of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the securities pursuant to an offer made under Section 275 of the SFA except:

(a) to an institutional investor or to a relevant person defined in Section 275(2) of the SFA, or to any person arising from an offer referred to in Section 275(1A) or Section 276(4)(i)(B) of the SFA;

(b) where no consideration is or will be given for the transfer;

(c) where the transfer is by operation of law;

(d) as specified in Section 276(7) of the SFA; or

(e) as specified in Regulation 32 of the Securities and Futures (Offers of Investments) (Shares and Debentures) Regulations 2005 of Singapore.

Notice to Prospective Investors in Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (Law No. 25 of 1948, as amended) and accordingly, will not be offered or sold, directly or indirectly, in Japan, or for the benefit of any Japanese Person or to others for re-offering or resale, directly or indirectly, in Japan or to any Japanese Person, except in compliance with all applicable laws, regulations and ministerial guidelines promulgated by relevant Japanese governmental or regulatory authorities in effect at the relevant time. For the purposes of this paragraph, “Japanese Person” shall mean any person resident in Japan, including any corporation or other entity organized under the laws of Japan.

Notice to Residents of Malaysia

The securities may not be offered for subscription or purchase and no invitation to subscribe for or purchase such Certificates in Malaysia may be made, directly or indirectly, and this prospectus or any document or other materials in connection therewith may not be distributed in Malaysia other than to persons falling within the categories specified under Schedule 6 or Section 229(l)(b), Schedule 7 or Section 230(l)(b) and Schedule 8 or Section 257(3) of the Capital Market and Services Act, 2007 of Malaysia. The Securities Commission of Malaysia shall not be liable for any non-disclosure on the part of the Issuer and assumes no responsibility for the correctness of any statements made or opinions or reports expressed in this prospectus.

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Notice to Prospective Investors in China

This prospectus does not constitute a public offer of the securities offered by this prospectus, whether by sale or subscription, in the People’s Republic of China, or the PRC. The securities are not being offered or sold directly or indirectly in the PRC to or for the benefit of, legal or natural persons of the PRC.

Further, no legal or natural persons of the PRC may directly or indirectly purchase any of the securities without obtaining all prior PRC’s governmental approvals that are required, whether statutorily or otherwise. Persons who come into possession of this document are required by the issuer and its representatives to observe these restrictions.

Notice to Prospective Investors in Korea

The securities have not been and will not be registered under the Financial Investments Services and Capital Markets Act of Korea and the decrees and regulations thereunder, or the FSCMA, and the securities have been and will be offered in Korea as a private placement under the FSCMA. None of the securities may be offered, sold or delivered directly or indirectly, or offered or sold to any person for re-offering or resale, directly or indirectly, in Korea or to any resident of Korea except pursuant to the applicable laws and regulations of Korea, including the FSCMA and the Foreign Exchange Transaction Law of Korea and the decrees and regulations thereunder, or the FETL. The securities have not been listed on any of securities exchanges in the world including, without limitation, the Korea Exchange in Korea. Furthermore, the purchaser of the securities shall comply with all applicable regulatory requirements (including but not limited to requirements under the FETL) in connection with the purchase of the securities. By the purchase of the securities, the relevant holder thereof will be deemed to represent and warrant that if it is in Korea or is a resident of Korea, it purchased the securities pursuant to the applicable laws and regulations of Korea.

Notice to Prospective Investors in Taiwan

The securities have not been and will not be registered with the Financial Supervisory Commission of Taiwan pursuant to relevant securities laws and regulations and may not be sold, issued or offered within Taiwan through a public offering or in circumstances which constitutes an offer within the meaning of the Securities and Exchange Act of Taiwan that requires a registration or approval of the Financial Supervisory Commission of Taiwan. No person or entity in Taiwan has been authorised to offer, sell, give advice regarding or otherwise intermediate the offering and sale of the securities in Taiwan.

Notice to Prospective Investors in Australia

No placement document, prospectus, product disclosure statement or other disclosure document has been lodged with the Australian Securities and Investments Commission (“ASIC”), in relation to the offering. This prospectus supplement does not constitute a prospectus, product disclosure statement or other disclosure document under the Corporations Act 2001 (the “Corporations Act”), and does not purport to include the information required for a prospectus, product disclosure statement or other disclosure document under the Corporations Act.

Any offer in Australia of the securities may only be made to persons (the “Exempt Investors”) who are “sophisticated investors” (within the meaning of section 708(8) of the Corporations Act), “professional investors” (within the meaning of section 708(11) of the Corporations Act) or otherwise pursuant to one or more exemptions contained in section 708 of the Corporations Act so that it is lawful to offer the securities without disclosure to investors under Chapter 6D of the Corporations Act. The securities applied for by Exempt Investors in Australia must not be offered for sale in Australia in the period of 12 months after the date of allotment under the offering, except in circumstances where disclosure to investors under Chapter 6D of the Corporations Act would not be required pursuant to an exemption under section 708 of the Corporations Act or otherwise or where

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the offer is pursuant to a disclosure document which complies with Chapter 6D of the Corporations Act. Any person acquiring securities must observe such Australian on-sale restrictions. This prospectus supplement contains general information only and does not take account of the investment objectives, financial situation or particular needs of any particular person. It does not contain any securities recommendations or financial product advice. Before making an investment decision, investors need to consider whether the information in this prospectus supplement is appropriate to their needs, objectives and circumstances, and, if necessary, seek expert advice on those matters.

Notice to Prospective Investors in the Cayman Islands

This prospectus does not constitute an invitation or offer to the public in the Cayman Islands of the securities, whether by way of sale or subscription. The underwriters have not offered or sold, and will not offer or sell, directly or indirectly, any securities in the Cayman Islands.

Notice to Prospective Investors in Bermuda

The securities offered by this prospectus may be offered or sold in Bermuda only in compliance with the provisions of the Investment Business Act of 2003 of Bermuda which regulates the sale of securities in Bermuda. Additionally, non-Bermudian persons (including companies) may not carry on or engage in any trade or business in Bermuda unless such persons are permitted to do so under applicable Bermuda legislation.

Notice to Prospective Investors in the British Virgin Islands

The securities are not being, and may not be offered to the public or to any person in the British Virgin Islands for purchase or subscription by us or on our behalf. The securities may be offered to companies incorporated under the BVI Business Companies Act, 2004 (British Virgin Islands) (each a BVI Company), but only where the offer will be made to, and received by, the relevant BVI Company entirely outside of the British Virgin Islands.

This prospectus has not been, and will not be, registered with the Financial Services Commission of the British Virgin Islands. No registered prospectus has been or will be prepared in respect of the securities for the purposes of the Securities and Investment Business Act, 2010, or SIBA or the Public Issuers Code of the British Virgin Islands.

The securities may be offered to persons located in the British Virgin Islands who are “qualified investors” for the purposes of SIBA. Qualified investors include (i) certain entities which are regulated by the Financial Services Commission in the British Virgin Islands, including banks, insurance companies, licensees under SIBA and public, professional and private mutual funds; (ii) a company, any securities of which are listed on a recognised exchange; and (iii) persons defined as “professional investors” under SIBA, which is any person (a) whose ordinary business involves, whether for that person’s own account or the account of others, the acquisition or disposal of property of the same kind as the property, or a substantial part of our property; or (b) who has signed a declaration that he, whether individually or jointly with his spouse, has net worth in excess of US$1,000,000 and that he consents to being treated as a professional investor.

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LEGAL MATTERS

The validity of the shares of common stock offered by this prospectus will be passed upon for us by Fenwick & West LLP, San Francisco, California. Certain legal matters relating to the offering will be passed upon for the underwriters by Cooley LLP, San Diego, California.

EXPERTS

The consolidated financial statements of AnaptysBio, Inc. as of December 31, 2015 and 2016, and for each of the years in the three-year period ended December 31, 2016, have been incorporated by reference herein and in the registration statement in reliance upon the report of KPMG LLP, an independent registered public accounting firm, incorporated by reference, and upon the authority of said firm as experts in accounting and auditing.

ADDITIONAL INFORMATION

We have filed with the SEC a registration statement on Form S-1 under the Securities Act with respect to the shares of common stock offered hereby. This prospectus, which constitutes a part of the registration statement, does not contain all of the information set forth in the registration statement or the exhibits filed therewith. For further information about us and the common stock offered hereby, reference is made to the registration statement and the exhibits filed therewith. Statements contained in this prospectus regarding the contents of any contract or any other document that is filed as an exhibit to the registration statement are not necessarily complete, and in each instance we refer you to the copy of such contract or other document filed as an exhibit to the registration statement. A copy of the registration statement and the exhibits filed therewith may be inspected without charge at the public reference room maintained by the SEC, located at 100 F Street, NE, Washington, DC 20549, and copies of all or any part of the registration statement may be obtained from that office. Please call the SEC at 1-800-SEC-0330 for further information about the public reference room. The SEC also maintains a website that contains reports, proxy and information statements and other information regarding registrants that file electronically with the SEC. The address of the website is www.sec.gov.

We are subject to the information and reporting requirements of the Exchange Act, and, in accordance with this law, file periodic reports and other information with the SEC. These periodic reports and other information are available for inspection and copying at the SEC’s public reference facilities and the website of the SEC referred to above. We also maintain a website at www.anaptysbio.com. You may access these materials free of charge as soon as reasonably practicable after they are electronically filed with, or furnished to, the SEC. Information contained on our website is not a part of this prospectus and the inclusion of our website address in this prospectus is an inactive textual reference only.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus.

We incorporate by reference into this prospectus and the registration statement of which this prospectus is a part the information or documents listed below that we have filed with the SEC (Commission File No. 001-37985).

• our Annual Report on Form 10-K for the year ended December 31, 2016, filed with the SEC on March 8, 2017;

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• our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2017 and June 30, 2017, filed with the SEC on May 12, 2017 and August 10, 2017, respectively; and

• our Current Reports on Form 8-K filed with the SEC on March 2, 2017, July 27, 2017, August 24, 2017 and October 10, 2017.

We will furnish without charge to you, on written or oral request, a copy of any or all of the documents incorporated by reference, including exhibits to these documents. You should direct any requests for documents to 10421 Pacific Center Court, Suite 200 San Diego, CA 92121, telephone (858) 362-6295. Copies of the above reports may also be accessed from our website at www.anaptysbio.com. We do not incorporate the information from our website into this prospectus or any supplement to this prospectus and you should not consider any information on, or that can be accessed through, our website as part of this prospectus or any supplement to this prospectus (other than those filings with the SEC that we specifically incorporate by reference into this prospectus or any supplement to this prospectus).

Any statement contained in a document incorporated or deemed to be incorporated by reference in this prospectus will be deemed modified, superseded or replaced for purposes of this prospectus to the extent that a statement contained in this prospectus modifies, supersedes or replaces such statement.

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3,000,000 Shares

AnaptysBio, Inc.

Common Stock

PRELIMINARY PROSPECTUS

Credit Suisse

Jefferies

Stifel

                    , 2017

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

The following table sets forth all costs and expenses, other than underwriting discounts and commissions, paid or payable by the Registrant in connection with the sale of the common stock being registered. All amounts shown are estimates except for the SEC registration fee and the FINRA filing fee:

	Amount Paid or to be Paid
SEC registration fee		$15,077
FINRA filing fee		16,250
Blue sky qualification fees and expenses		10,000
Printing and engraving expenses		62,500
Legal fees and expenses		215,000
Accounting fees and expenses		35,000
Transfer agent and registrar fees and expenses		3,500
Miscellaneous expenses		50,000
Total		$407,327

ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation’s board of directors to grant, indemnity to directors and officers under certain circumstances and subject to certain limitations. The terms of Section 145 of the Delaware General Corporation Law are sufficiently broad to permit indemnification under certain circumstances for liabilities, including reimbursement of expenses incurred, arising under the Securities Act.

As permitted by the Delaware General Corporation Law, the Registrant’s restated certificate of incorporation to be effective in connection with the closing of this offering contains provisions that eliminate the personal liability of its directors for monetary damages for any breach of fiduciary duties as a director, except liability for the following:

• any breach of the director’s duty of loyalty to the Registrant or its stockholders;

• acts or omissions not in good faith or that involve intentional misconduct or a knowing violation of law;

• under Section 174 of the Delaware General Corporation Law (regarding unlawful dividends and stock purchases); or

• any transaction from which the director derived an improper personal benefit.

As permitted by the Delaware General Corporation Law, the Registrant’s restated bylaws to be effective upon the closing of this offering, provide that:

• the Registrant is required to indemnify its directors and executive officers to the fullest extent permitted by the Delaware General Corporation Law, subject to limited exceptions;

• the Registrant may indemnify its other employees and agents as set forth in the Delaware General Corporation Law;

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• the Registrant is required to advance expenses, as incurred, to its directors and executive officers in connection with a legal proceeding to the fullest extent permitted by the Delaware General Corporation Law, subject to limited exceptions; and

• the rights conferred in the restated bylaws are not exclusive.

The Registrant has entered into indemnification agreements with each of its current directors and executive officers to provide these directors and executive officers additional contractual assurances regarding the scope of the indemnification set forth in the Registrant’s restated certificate of incorporation and restated bylaws and to provide additional procedural protections. There is no pending litigation or proceeding involving a director or executive officer of the Registrant for which indemnification is sought. Reference is also made to Section 9 of the underwriting agreement to be filed as Exhibit 1.1 to this registration statement, which provides for the indemnification of executive officers, directors and controlling persons of the Registrant against certain liabilities. The indemnification provisions in the Registrant’s restated certificate of incorporation, restated bylaws and the indemnification agreements entered into or to be entered into between the Registrant and each of its directors and executive officers may be sufficiently broad to permit indemnification of the Registrant’s directors and executive officers for liabilities arising under the Securities Act.

The Registrant currently carries liability insurance for its directors and officers.

Reference is made to the following documents filed as exhibits to this Registration Statement regarding relevant indemnification provisions described above and elsewhere herein:

Exhibit Document	Number
Form of Underwriting Agreement		1.1
Restated Certificate of Incorporation		3.1
Restated Bylaws		3.2
Fourth Amended and Restated Investors’ Rights Agreement dated July 13, 2015 among the Registrant and certain of its stockholders		4.2
Form of Indemnity Agreement		10.1

ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES.

The following lists set forth information regarding all securities sold or granted by us within the past three years that were not registered under the Securities Act, and the consideration, if any, received by us for such securities:

(a) Stock Option Grants

Between August 31, 2014 until January 26, 2017, the Registrant granted options to purchase 1,760,974 shares of common stock under its 2006 Equity Incentive Plan to its directors, officers, employees, consultants, and other service providers with per share exercise prices ranging from $0.70 to $11.34. During this same period, the Registrant issued 174,139 shares of common stock upon exercise of stock options previously issued under the 2006 Equity Incentive Plan to its directors, officers, employees, consultants, and other service providers for cash consideration in the aggregate amount of $195,180.

The stock options and the common stock issuable upon the exercise of such options as described in this section (a) of Item 15 were issued pursuant to written compensatory plans or arrangements with the Company’s employees and directors in reliance on the exemption provided by Rule 701 promulgated under the Securities Act. All recipients either received adequate information about the Company or had access, through employment or other relationships, to such information.

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(b) Warrants

In December 2014, the Registrant issued warrants to accredited investors to purchase an aggregate of 41,208 shares of the Registrant’s Series C convertible preferred stock. The preferred stock warrants have a per share exercise price of $4.55. The securities issued in this transaction were exempt from the registration requirements of the Securities Act in reliance upon Section 4(a)(2) under the Securities Act.

In December 2016, the Registrant issued warrants to accredited investors to purchase an aggregate of 82,416 shares of the Registrant’s Series C convertible preferred stock. The preferred stock warrants have a per share exercise price of $4.55. The securities issued in this transaction were exempt from the registration requirements of the Securities Act in reliance upon Section 4(a)(2) under the Securities Act.

Since January 31, 2017, the Registrant has issued a total of 397,445 shares of common stock pursuant to the exercise of warrants, each with an exercise price of $4.55 per share. The securities issued in this transaction were exempt from the registration requirements of the Securities Act in reliance upon Section 4(a)(2) under the Securities Act.

(c) Sales of Preferred Stock

In July 2015, the Registrant issued an aggregate of 5,490,973 shares of the Registrant’s Series D convertible preferred stock at a purchase price of $7.42 per share for an aggregate purchase price of $40.8 million to 19 purchasers that represented to us that they are each a sophisticated accredited investor and qualified institutional buyer. The securities issued in this transaction were exempt from registration requirements of the Securities Act in reliance on Rule 506 promulgated under the Securities Act.

None of the foregoing transactions involved any underwriters, underwriting discounts or commissions or any public offering, and the Registrant believes each transaction was exempt from the registration requirements of the Securities Act as stated above. All recipients of the foregoing transactions either received adequate information about the Registrant or had access, through their relationships with the Registrant, to such information. Furthermore, the Registrant affixed appropriate legends to the share certificates and instruments issued in each foregoing transaction setting forth that the securities had not been registered and the applicable restrictions on transfer.

ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

(a) Exhibits.

Exhibit Number

Description of Document

Form

File No.

Incorporated by Reference Exhibit No.

Filing Date

Filed Herewith

1.1

Form of Underwriting Agreement, including Form of Lock-Up Agreement.

X

3.1

Restated Certificate of Incorporation.

10-Q

001-37985

3.1

May 12, 2017

3.2

Restated Bylaws.

S-1

333-206849

3.4

September 9, 2015

4.1

Form of Common Stock Certificate.

S-1/A

333-206849

4.1

December 23, 2015

4.2

Fourth Amended and Restated Investors’ Rights Agreement, dated July  13, 2015, by and among the Registrant and certain of its stockholders.

S-1

333-206849

4.2

September 9, 2015

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Exhibit Number		Description of Document	Form		File No.		Incorporated by Reference Exhibit No.		Filing Date		Filed Herewith
	5.1	Opinion of Fenwick & West LLP.										X
	10.1	Form of Indemnity Agreement.		S-1		333-206849		10.1		September 9, 2015
	10.2	Amended and Restated 2006 Equity Incentive Plan and forms of award agreements.		S-1/A		333-206849		10.2		January 17, 2017
	10.3	2017 Equity Incentive Plan and forms of award agreements.		S-1/A		333-206849		10.3		January 17, 2017
	10.4	2017 Employee Stock Purchase Plan and forms of award agreements.		S-1/A		333-206849		10.4		January 17, 2017
	10.5	Employment Agreement, effective as of January 1, 2012, by and between the Registrant and Hamza  Suria, as amended.		S-1		333-206849		10.5		September 9, 2015
	10.6	Employment Agreement, effective as of March 22, 2016, by and between the Registrant and Matthew Moyle.		S-1/A		333-206849		10.6		December 28, 2016
	10.7	Employment Agreement, effective as of October 20, 2014, by and between the Registrant and Marco Londei.		S-1		333-206849		10.8		September 9, 2015
	10.8	Employment Agreement, effective as of January 9, 2017, by and between the Registrant and Dominic Piscitelli.										X
	10.9	Office Lease, dated April 19, 2011, by and between the Registrant and Kilroy Realty, L.P., as amended.		S-1/A		333-206849		10.8		December 23, 2015
	10.10	Antibody Generation Agreement, dated December  22, 2011, by and between the Registrant and Celgene Corporation, as modified.		S-1/A		333-206849		10.9		December 28, 2016
	10.11+	Collaboration and Exclusive License Agreement, dated March 10, 2014, by and  among the Registrant, TESARO, Inc. and TESARO Development, Ltd., as amended.		S-1/A		333-206849		10.10		May 10, 2016

II-4

Exhibit Number

Description of Document

Form

File No.

Incorporated by Reference Exhibit No.

Filing Date

Filed Herewith

10.12+

License Agreement, dated August 30, 2006, by and between the Registrant and Medical Research Council, as amended.

S-1

333-206849

10.12

September 9, 2015

10.13+

Non-Exclusive Research and Commercial License Agreement, dated May  15, 2009, by and between the Registrant and Millipore Corporation.

S-1

333-206849

10.13

September 9, 2015

10.14

Loan and Security Agreement, dated December  24, 2014, by and among the Registrant, Oxford Finance LLC and Silicon Valley Bank, as amended.

S-1/A

333-206849

10.13

February 16, 2016

21.1

Subsidiaries of the Registrant.

10-K

001-37985

21.1

March 8, 2017

23.1

Consent of KPMG LLP, an independent registered public accounting firm.

X

23.2

Consent of Fenwick & West LLP (included in Exhibit 5.1).

X

24.1

Power of Attorney (reference is made to the signature page hereto).

X

+ Registrant has omitted and filed separately with the SEC portions of the exhibit pursuant to a confidential treatment request under Rule 406 promulgated under the Securities Act.

(b) Financial Statement Schedules.

No financial statement schedules are provided because the information called for is not required or is shown either in the financial statements or notes.

ITEM 17. UNDERTAKINGS.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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The undersigned Registrant hereby undertakes that:

(a) For purposes of determining any liability under the Securities Act, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this registration statement as of the time it was declared effective.

(b) For the purpose of determining any liability under the Securities Act, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

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SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant has duly caused this amendment to the registration statement on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized, in San Diego, California, on the 10th day of October, 2017.

ANAPTYSBIO, INC.

/s/ Hamza Suria

Hamza Suria

Chief Executive Officer

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Hamza Suria and Dominic G. Piscitelli, and each of them, as his or her true and lawful attorneys-in-fact, proxies and agents, each with full power of substitution, for him or her in any and all capacities, to sign any and all amendments to this registration statement (including post-effective amendments or any abbreviated registration statement and any amendments thereto filed pursuant to Rule 462(b) increasing the number of securities for which registration is sought), and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact, proxies and agents full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully for all intents and purposes as he or her might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact, proxies and agents, or their or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement on Form S-1 has been signed by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/s/ Hamza Suria Hamza Suria	President, Chief Executive Officer and Director (Principal Executive Officer)	October 10, 2017
/s/ Dominic G. Piscitelli Dominic G. Piscitelli	Chief Financial Officer (Principal Accounting and Financial Officer)	October 10, 2017
/s/ Carol G. Gallagher, Pharm.D. Carol G. Gallagher, Pharm.D.	Director	October 10, 2017
/s/ Nicholas B. Lydon, Ph.D., FRS Nicholas B. Lydon, Ph.D., FRS	Director	October 10, 2017
/s/ Hollings Renton Hollings Renton	Director	October 10, 2017
/s/ John Schmid John Schmid	Director	October 10, 2017
/s/ James A. Schoeneck James A. Schoeneck	Director	October 10, 2017

Signature	Title	Date
/s/ James N. Topper, M.D., Ph.D. James N. Topper, M.D., Ph.D.	Director	October 10, 2017
/s/ J. Anthony Ware J. Anthony Ware	Director	October 10, 2017

EX-1.1

Exhibit 1.1

[•] Shares

ANAPTYSBIO, INC.

Common Stock, par value $0.001 per share

UNDERWRITING AGREEMENT

October [•], 2017

CREDIT SUISSE SECURITIES (USA) LLC

JEFFERIES LLC

STIFEL, NICOLAUS & COMPANY, INCORPORATED,

As Representatives of the Several Underwriters,

c/o Credit Suisse Securities (USA) LLC,

Eleven Madison Avenue

New York, New York 10010-3629

c/o Jefferies LLC

520 Madison Avenue

New York, New York 10022

and

c/o Stifel, Nicolaus & Company, Incorporated

One Montgomery Street, Suite 3700

San Francisco, California 94104

Ladies and Gentlemen:

AnaptysBio, Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell an aggregate of [•] shares (the “Firm Shares”) of the Company’s common stock, $0.001 par value per share (the “Common Stock”), to the several underwriters (collectively, the “Underwriters”) named in Schedule I to this agreement (this “Agreement”), for whom Credit Suisse Securities (USA) LLC, Jefferies LLC and Stifel, Nicolaus & Company, Incorporated are acting as representatives (the “Representatives”). The Company has also agreed to grant to the Underwriters an option (the “Option”) to purchase up to an additional [•] shares of Common Stock (the “Option Shares”) on the terms set forth in Section 1(b) hereof. The Firm Shares and the Option Shares are hereinafter collectively referred to as the “Shares.”

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The Company confirms as follows its agreement with the Representatives and the several other Underwriters:

1. Agreement to Sell and Purchase.

(a) Purchase of Firm Shares. On the basis of the representations, warranties and agreements of the Company contained herein and subject to all the terms and conditions of this Agreement, the Company agrees to sell to the several Underwriters and each of the several Underwriters, severally and not jointly, agrees to purchase from the Company, at a purchase price per share of $[•] (the “Purchase Price”), the number of Firm Shares set forth opposite the name of such Underwriter in Schedule I, plus such additional number of Firm Shares which such Underwriter may become obligated to purchase pursuant to Section 8 hereof.

(b) Purchase of Option Shares. Subject to all the terms and conditions of this Agreement, the Company grants the Option to the several Underwriters to purchase, severally and not jointly, the Option Shares at the Purchase Price less an amount per share equal to any dividends or distributions declared by the Company and payable on the Firm Shares but not payable on the Option Shares. The Option may be exercised in whole or in part at any time on or before the 30th day after the date of this Agreement, upon written notice (the “Option Shares Notice”) by the Representatives to the Company no later than 12:00 noon, New York City time, at least two and no more than five business days before the date specified for closing in the Option Shares Notice (the “Option Closing Date”) setting forth the aggregate number of Option Shares to be purchased and the time and date for such purchase. On the Option Closing Date, the Company shall issue and sell to the Underwriters the number of Option Shares set forth in the Option Shares Notice and each Underwriter shall purchase from the Company such percentage of the Option Shares as is equal to the percentage of Firm Shares that such Underwriter is purchasing, as adjusted by the Representatives in such manner as they deem advisable to avoid fractional shares.

2. Delivery and Payment.

(a) Closing. Delivery of the Firm Shares shall be made to the Representatives through the facilities of the Depository Trust Company (“DTC”) for the respective accounts of the Underwriters against payment of the Purchase Price by wire transfer of immediately available funds to the Company. Such payment shall be made at 10:00 a.m., New York City time, on the third business day (the fourth business day, should the offering be priced after 4:00 p.m., Eastern Time) after the date on which the first bona fide offering of the Firm Shares to the public is made by the Underwriters or at such time on such other date, not later than ten business days after such date, as may be agreed upon by the Company and the Representatives (such date is hereinafter referred to as the “Closing Date”).

(b) Option Closing. To the extent the Option is exercised, delivery of the Option Shares against payment by the Representatives (in the manner and at the location specified above) shall take place at the time and date (which may be the Closing Date, but not earlier than the Closing Date) specified in the Option Shares Notice.

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(c) Electronic Transfer. Electronic transfer of Shares shall be made at the time of purchase in such names and in such denominations as the Representatives shall specify.

(d) Tax Stamps. The cost of original issue tax stamps, if any, in connection with the issuance and delivery of the Shares by the Company to the respective Underwriters shall be borne by the Company. The Company shall pay and hold each Underwriter and any subsequent holder of the Shares harmless from any and all liabilities with respect to or resulting from any failure or delay in paying Federal and state stamp and other transfer taxes, if any, which may be payable or determined to be payable in connection with the original issuance or sale to such Underwriter of the Shares.

3. Representations and Warranties of the Company. The Company represents and warrants to, and covenants with, each Underwriter as follows:

(a) Compliance with Registration Requirements. A registration statement on Form S-1 (Registration No. 333-[•]) relating to the Shares, including a preliminary prospectus and such amendments to such registration statement as may have been required to the date of this Agreement, has been prepared by the Company under the provisions of the Securities Act of 1933, as amended (the “Act”), and the rules and regulations (collectively referred to as the “Rules and Regulations”) of the Securities and Exchange Commission (the “Commission”) thereunder, and has been filed with the Commission. Copies of such registration statement and of each amendment thereto, if any, including the related preliminary prospectuses, heretofore filed by the Company with the Commission have been delivered to the Representatives. The term “Registration Statement” means the registration statement as amended at the time it becomes or became effective, including financial statements and all exhibits, all documents incorporated by reference therein and any information deemed to be included therein by Rule 430A, Rule 430B or Rule 430C of the Rules and Regulations, as applicable. If the Company files a registration statement to register a portion of the Shares and relies on Rule 462(b) of the Rules and Regulations for such registration statement to become effective upon filing with the Commission (the “Rule 462 Registration Statement”), then any reference to the “Registration Statement” shall be deemed to include the Rule 462 Registration Statement, as amended from time to time. The term “preliminary prospectus” as used herein means a preliminary prospectus as contemplated by Rule 430, Rule 430A or Rule 430B of the Rules and Regulations included at any time as part of, or deemed to be part of or included in, the registration statement. The term “Prospectus” means the final prospectus in connection with this offering as first filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations or, if no such filing is required, the form of final prospectus included in the Registration Statement at the effective date. The term “Testing-the-Waters Communication” means any oral or written communication with potential investors in reliance on Section 5(d) of the Act. The term “Written Testing-the-Waters Communication” means any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 of the Rules and Regulations.

(b) Effectiveness of Registration. The Registration Statement, any Rule 462 Registration Statement and any post-effective amendment thereto have been declared effective by the Commission under the Act or have become effective pursuant to Rule 462 of the Rules and Regulations. The Company has responded to all requests, if any, of the Commission for additional or supplemental information. No stop order suspending the effectiveness of the Registration Statement or any Rule 462 Registration Statement is in effect and no proceedings for such purpose have been instituted or are pending or, to the knowledge of the Company, are threatened by the Commission.

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(c) Accuracy of Registration Statement. Each of the Registration Statement, any Rule 462 Registration Statement and any post-effective amendment thereto, at the time it became effective and at the Closing Date and the Option Closing Date, complied and will comply in all material respects with the Act and the Rules and Regulations, and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading. The Prospectus, as amended or supplemented, as of its date and at the Closing Date and the Option Closing Date, complied and will comply in all material respects with the Act and the Rules and Regulations, and did not or will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein not misleading, in the light of the circumstances under which they were made. Each preliminary prospectus (including the preliminary prospectus or prospectuses filed as part of the Registration Statement or any amendment thereto) complied when so filed in all material respects with the Rules and Regulations, and each preliminary prospectus and the Prospectus delivered to the Underwriters for use in connection with this offering is identical to the electronically transmitted copies thereof filed with the Commission on the Commission’s Electronic Data Gathering, Analysis and Retrieval system or any successor system (“EDGAR”), except to the extent permitted by Regulation S-T. The foregoing representations and warranties in this Section 3(c) do not apply to any statements or omissions made in reliance on and in conformity with information relating to any Underwriter furnished in writing to the Company by the Representatives specifically for inclusion in the Registration Statement or Prospectus or any amendment or supplement thereto. For all purposes of this Agreement, [•] set forth in the Prospectus under the caption “Underwriting” constitute the only information (the “Underwriters’ Information”) relating to any Underwriter furnished in writing to the Company by the Representatives specifically for inclusion in the preliminary prospectus, the Registration Statement or the Prospectus.

(d) Company Not Ineligible Issuer. (i) At the time of filing the Registration Statement relating to the Shares and (ii) as of the date of the execution and delivery of this Agreement (with such date being used as the determination date for purposes of this clause (ii)), the Company was not and is not an “ineligible issuer” (as defined in Rule 405 of the Rules and Regulations).

(e) Disclosure at the Time of Sale. As of the Applicable Time (as defined below), neither (i) the Issuer General Use Free Writing Prospectus(es) (as defined below) issued at or prior to the Applicable Time, the most recent preliminary prospectus related to this offering, and the information included on Schedule III hereto, all considered together (collectively, the “General Disclosure Package”), nor (ii) any individual Issuer Limited Use Free Writing Prospectus (as defined below), when considered together with the General Disclosure Package, , when considered together with the General Disclosure Package, included any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the General Disclosure Package based upon and in conformity with written information furnished to the Company by any Underwriter through the Representatives specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the Underwriters’ Information.

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As used in this subsection and elsewhere in this Agreement:

“Applicable Time” means [•] p.m. (Eastern Time) on [•], 2017 or such other time as agreed by the Company and the Representative(s).

“Issuer Free Writing Prospectus” means any “issuer free writing prospectus,” as defined in Rule 433 of the Rules and Regulations, relating to the Shares that (i) is required to be filed with the Commission by the Company, (ii) is a “a written communication that is a road show” within the meaning of Rule 433(d)(8)(i), whether or not required to be filed with the Commission or (iii) is exempt from filing pursuant to Rule 433(d)(5)(i) because it contains a description of the Shares or of the offering that does not reflect the final terms, in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g); provided, however, that a Written Testing-the-Waters Communication shall be deemed not to be an Issuer Free Writing Prospectus.

“Issuer General Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is intended for general distribution to prospective investors, as evidenced by its being specified in Schedule II hereto.

“Issuer Limited Use Free Writing Prospectus” means any Issuer Free Writing Prospectus that is not an Issuer General Use Free Writing Prospectus.

All references in this Agreement to the Registration Statement, any preliminary prospectus, the General Disclosure Package and the Prospectus shall include the documents incorporated by reference therein. All references in this Agreement to financial statements and schedules and other information which are “contained,” “included,” “stated” or “set forth” in the Registration Statement, any preliminary prospectus, the General Disclosure Package or the Prospectus, and all other references of like import, shall be deemed to mean and include all such financial statements and schedules and other information which is incorporated by reference in the Registration Statement, any preliminary prospectus, the General Disclosure Package or the Prospectus, as the case may be.

(f) Incorporation of Documents by Reference. The Company meets the requirements to incorporate documents by reference in the Registration Statement pursuant to General Instruction VII to Form S-1 under the Act and the Rules and Regulations. The documents incorporated by reference in the Registration Statement, any preliminary prospectus, the General Disclosure Package and the Prospectus, at the time they were filed with the Commission, or became effective under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), as the case may be, complied in all material respects with the requirements of the Exchange Act and the rules and regulations of the Commission under the Exchange Act (the “Exchange Act Regulations”).

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(g) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the Prospectus Delivery Period (defined below), does not include any information that conflicts with the information contained in the Registration Statement. The foregoing sentence does not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with the Underwriters’ Information. If at any time following the issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information contained in the Registration Statement relating to the Shares or included or would include an untrue statement of material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in light of the circumstances prevailing at that subsequent time, not misleading, the Company has promptly notified or will promptly notify the Representatives and has promptly amended or will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict, untrue statement, or omission.

(h) Distribution of Offering Material by the Company. The Company has not distributed and will not distribute, prior to the later of the Closing Date and the completion of the Underwriters’ distribution of the Shares, any offering material in connection with the offering or sale of the Shares other than the Registration Statement, the preliminary prospectus, the Permitted Free Writing Prospectuses reviewed and consented to by the Representatives and included in Schedule II hereto, and the Prospectus.

(i) Due Incorporation; Subsidiary.

(i) The Company is, and at the Closing Date will be, a corporation duly organized, validly existing and in good standing under the laws of its jurisdiction of incorporation. The Company has, and at the Closing Date will have, full power and authority to conduct all the activities conducted by it, to own or lease all the assets owned or leased by it and to conduct its business as described in the Registration Statement, the General Disclosure Package and the Prospectus. The Company is, and at the Closing Date will be, duly licensed or qualified to do business in and in good standing as a foreign corporation in all jurisdictions in which the nature of the activities conducted by it or the character of the assets owned or leased by it makes such licensing or qualification necessary, except to the extent that the failure to be so qualified or be in good standing would not (i) have a material adverse effect on the business, properties, assets, business prospects, financial condition, results of operations or capitalization of the Company and its subsidiary, taken as a whole, or (ii) prevent or materially interfere with the consummation of the transactions contemplated by this Agreement or the performance by the Company of its obligations hereunder (any such effect, prevention or interference, a “Material Adverse Effect”).

(ii) AnaptysBio Pty Ltd. is the only subsidiary of the Company (as defined in Rule 405 of the Rules and Regulations), and has been duly incorporated, is validly existing as a corporation in good standing under the laws of the jurisdiction of its incorporation, has the corporate power and authority to own its property and to conduct its business as described in the Registration Statement, the General Disclosure Package and Prospectus and is duly qualified to transact business and is in good standing, if applicable, in each jurisdiction in which such qualification is required, except to the extent that the failure to be so qualified or be

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in good standing would not have a Material Adverse Effect; all of the issued share capital or other equity interests of AnaptysBio Pty Ltd. have been duly and validly authorized and issued, are fully paid and non-assessable and are owned directly by the Company, free and clear of all liens, charges, encumbrances, equities, security interests, restrictions on voting or transfer or any other claims.

(j) Capitalization. The authorized, issued and outstanding capital stock of the Company is as set forth in the Registration Statement, the General Disclosure Package and the Prospectus under the caption “Capitalization.” The outstanding shares of Common Stock and any other outstanding capital stock of the Company have been, and the Shares will be, duly authorized, validly issued, fully paid and non-assessable and will not be subject to any preemptive, first refusal, or similar right. The description of the Common Stock included in the Registration Statement, the General Disclosure Package and the Prospectus is now, and at the Closing Date will be, complete and accurate in all material respects. Except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, the Company does not have outstanding, and at the Closing Date will not have outstanding, any options to purchase, or any rights or warrants to subscribe for, or any securities or obligations convertible into, or any contracts or commitments to issue or sell, any shares of capital stock of the Company or any such warrants, convertible securities or obligations. Upon the issuance and delivery pursuant to the terms of this Agreement, the Underwriters will acquire good and marketable title to the Shares, free and clear of any lien, charge, claim, encumbrance, pledge, security interest, defect or other restriction or equity of any kind whatsoever.

(k) Financial Statements. The financial statements (including the related notes thereto) and schedules included in the Registration Statement, the General Disclosure Package and the Prospectus present fairly the financial condition of the Company and its consolidated subsidiary as of the respective dates thereof and their results of operations and cash flows for the respective periods covered thereby, all in conformity with generally accepted accounting principles applied in the United States on a consistent basis throughout the entire period involved. The selected financial data and the summary financial information included in the Registration Statement, the General Disclosure Package and the Prospectus present fairly, in all material respects, the information shown therein and have been compiled on a basis consistent with that of the financial statements included therein and the books and records of the Company and its consolidated subsidiary. The pro forma financial statements, if any, and the other pro forma financial information included in the Registration Statement, the General Disclosure Package and the Prospectus present fairly, in all material respects, the information shown therein, have been prepared in accordance with the Commission’s rules and guidelines with respect to pro forma financial statements and have been properly computed on the bases described therein. The assumptions used in the preparation of the pro forma financial statements, if any, and other pro forma financial information included in the Registration Statement, the General Disclosure Package and the Prospectus are reasonable and the adjustments used therein are appropriate to give effect to the transactions or circumstances referred to therein. No other financial statements, schedules or reconciliations of “non-GAAP financial measures” (as such term is defined by the rules and regulations of the Commission) of the Company are required by the Act, the Exchange Act, the Rules and Regulations or the Exchange Act Regulations to be included in the Registration Statement, the General Disclosure Package and the Prospectus. The interactive data in eXtensible Business Reporting Language included or included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospectus fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto.

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(l) Independent Accountants. KPMG LLP (the “Accountants”), who certified the financial statements and supporting schedules of the Company and its consolidated subsidiary included in the Registration Statement, the General Disclosure Package and the Prospectus, are (i) independent accountants as required by the Act, the Exchange Act, the Rules and Regulations, the Exchange Act Regulations and by the rules of the Public Company Accounting Oversight Board (United States) (the “PCAOB”), (ii) in compliance with the applicable requirements relating to the qualification of accountants under Rule 2-01 of Regulation S-X under the Act, and (iii) a registered public accounting firm as defined by the PCAOB whose registration has not been suspended or revoked and who has not requested such registration to be withdrawn.

(m) No Material Adverse Changes. Since the respective dates as of which information is given in the Registration Statement and the Prospectus and prior to the Closing Date and any Option Closing Date, except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, (i) there has not been a material adverse change, or any development that would be expected to result in a material adverse change, in the business, properties, assets, business prospects, financial condition, results of operations or capitalization of the Company and its subsidiary, taken as a whole, arising for any reason whatsoever (a “Material Adverse Change”), (ii) the Company has not incurred, nor will it incur, any material liabilities or obligations, direct or contingent, nor has it entered into, nor will it enter into, any material transactions not in the ordinary course of business, other than pursuant to this Agreement and the transactions referred to herein, and (iii) the Company has not and will not have paid or declared any dividends or other distributions of any kind on any class of its capital stock.

(n) Investment Company. The Company is not, and, after giving effect to the issuance and sale of the Shares and the use of the proceeds therefrom as described in the General Disclosure Package and the Prospectus, will not be, an “investment company” or an “affiliated person” of, or “promoter” or “principal underwriter” for, an “investment company,” as such terms are defined in the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission promulgated thereunder.

(o) Litigation. Except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, there are no actions, suits or proceedings pending, or to the Company’s knowledge, threatened against or affecting, the Company or its subsidiary or any of its officers in their capacity as such, before or by any federal or state court, commission, regulatory body, including the Financial Industry Regulatory Authority, Inc. (“FINRA”) and the Nasdaq Stock Market LLC, administrative agency or other governmental body, domestic or foreign, wherein an unfavorable ruling, decision or finding would reasonably be expected to have a Material Adverse Effect. The Company has not received any notice of proceedings relating to the revocation or modification of any authorization, approval, order, license, certificate, franchise or permit. There are no pending investigations known to the Company involving the Company by any governmental agency having jurisdiction over the Company or its business or operations.

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(p) Compliance with Laws and Regulations and Performance of Obligations and Contracts. The Company and its subsidiary have, and at the Closing Date will have, (i) complied in all material respects with all laws, regulations and orders applicable to it or its business and (ii) performed in all material respects the obligations required to be performed by it, and is not, and at the Closing Date will not be, in default under any indenture, mortgage, deed of trust, voting trust agreement, loan agreement, bond, debenture, note agreement, lease or other agreement or instrument (individually, a “Contract” and collectively, “Contracts”) to which it is a party or by which its property is bound or affected. To the knowledge of the Company, no other party under any Contract to which it is a party is in default in any respect thereunder or has given written or oral notice to the Company or any of its officers or directors of such other party’s intention to terminate, cancel or refuse to renew any Contract. The Company is not now, and at the Closing Date will not be, in violation of any provision of its certificate of incorporation or by-laws. The disclosures included in the Registration Statement, the General Disclosure Package and the Prospectus concerning the effects of Federal, state, local and foreign laws, rules and regulations on the business of the Company as currently conducted and as proposed to be conducted are correct in all material respects.

(q) No Consent of Governmental Body Needed. No consent, approval, authorization, license, registration, qualification or order of, or any filing or declaration with, any court or arbitrator or governmental or regulatory authority, agency or body is required in connection with the authorization, issuance, transfer, sale or delivery of the Shares by the Company, in connection with the execution, delivery and performance of this Agreement by the Company or in connection with the taking by the Company of any action contemplated hereby, except as have been obtained under the Act and such as may be required under state securities or Blue Sky laws or the by-laws and rules of FINRA in connection with the purchase and distribution by the Underwriters of the Shares to be sold by the Company.

(r) Agreement Duly Authorized. The Company has full corporate power and authority to enter into this Agreement. This Agreement has been duly authorized, executed and delivered by the Company and constitutes a valid and binding agreement of the Company enforceable against the Company in accordance with the terms hereof, except as the enforcement may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting creditors’ rights generally or general equitable principles.

(s) No Conflicts. The execution and delivery by the Company of this Agreement and the performance of this Agreement, the consummation of the transactions contemplated hereby, and the application of the net proceeds from the offering and sale of the Shares to be sold by the Company in the manner set forth in the General Disclosure Package and the Prospectus under “Use of Proceeds” do not and will not (i) violate the certificate of incorporation or by-laws of the Company or (ii) result in the creation or imposition of any lien, charge or encumbrance upon any of the assets of the Company or its subsidiary pursuant to the terms or provisions of, or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or give any other party a right to terminate any of its obligations under, or result in the acceleration of any obligation under any Contract to which the Company

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or its subsidiary is a party or by which the Company or its subsidiary or any of its properties is bound or affected, or violate or conflict with any judgment, ruling, decree, order, law, statute, rule or regulation of any court or other governmental agency or body applicable to the business or properties of the Company or its subsidiary, except, in the case of clause (ii) above, as would not be expected to have a Material Adverse Effect.

(t) Title to Real and Personal Property. The Company and its subsidiary have good and marketable title to all properties and assets described in the Registration Statement, the General Disclosure Package and the Prospectus as being owned respectively by it, free and clear of all liens, charges, encumbrances or restrictions, except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus or are not material to the business of the Company or its subsidiary. The Company and its subsidiary have valid, subsisting and enforceable leases for the properties described in the General Disclosure Package and the Prospectus as leased by them, with such exceptions as are not material and do not materially interfere with the use made and proposed to be made of such properties by the Company and its subsidiary.

(u) Documents Described in Registration Statement. There is no document or Contract required to be described in the Registration Statement, the General Disclosure Package and the Prospectus or to be filed as an exhibit to the Registration Statement that is not described or filed as required. All such documents and Contracts described in the Registration Statement, General Disclosure Package and the Prospectus or filed as an exhibit to the Registration Statement were duly authorized, executed and delivered by the Company, constitute valid and binding agreements of the Company and are enforceable against the Company in accordance with the terms thereof.

(v) No Untrue Statement; Statistical and Market Data. No statement, representation, warranty or covenant made by the Company in this Agreement or made in any certificate or document required by this Agreement to be delivered to Representatives was or will be, when made, inaccurate, untrue or incorrect. All statistical or market-related data included in the Registration Statement, the General Disclosure Package and the Prospectus are based on or derived from sources that the Company believes to be reliable and accurate, and the Company has obtained the written consent to the use of such data from such sources to the extent required.

(w) No Price Stabilization or Manipulation. Neither the Company nor any of its directors, officers or controlling persons has taken, directly or indirectly, any action intended to cause or result in, or which might reasonably be expected to cause or result in, or which has constituted, stabilization or manipulation, under the Act or otherwise, of the price of any security of the Company to facilitate the sale or resale of the Shares.

(x) No Registration Rights. No holder of securities of the Company has rights to register any securities of the Company because of the filing of the Registration Statement, the Prospectus or the offering of the Shares, except for rights that have been duly waived with respect to such holder, have expired or have been fulfilled by registration prior to the date of this Agreement.

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(y) Stock Exchange Listing. The Shares are registered pursuant to Section 12(b) of the Exchange Act and are listed on the NASDAQ Global Select Market, and the Company has taken no action designed to, or likely to have the effect of, terminating the registration of the Shares under the Exchange Act or delisting the Shares from the NASDAQ Global Select Market, nor has the Company received any notification that the Commission or the NASDAQ Global Select Market is contemplating terminating such registration or listing. To the Company’s knowledge, it is in compliance with all applicable listing requirements of the NASDAQ Global Select Market.

(z) Labor Matters. Neither the Company nor its subsidiary is involved in any labor dispute except, where the dispute would not, individually or in the aggregate, have a Material Adverse Effect, nor, to the knowledge of the Company, is any such dispute threatened.

(aa) No Unlawful Payments. Neither the Company nor its subsidiary, nor any director or officer of the Company or its subsidiary, nor, to the knowledge of the Company, any agent, employee or representative of the Company or its subsidiary, affiliate or other person associated with or acting on behalf of the Company or its subsidiary, has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made or taken an act in furtherance of an offer, promise or authorization of any direct or indirect unlawful payment of corporate funds or benefit to any foreign or domestic government or regulatory official or employee, including, without limitation, of any government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office; (iii) violated or is in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977, as amended, the U.K. Bribery Act 2010, or any applicable law or regulation implementing the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions, or committed an offense under any other applicable anti-bribery or anti-corruption laws; or (iv) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including, without limitation, any rebate, payoff, influence payment, kickback or other unlawful or improper payment or benefit. The Company has instituted, maintained and enforced, and will continue to maintain and enforce policies and procedures designed to promote and ensure compliance with all applicable anti-bribery and anti-corruption laws.

(bb) Compliance with Anti-Money Laundering Laws. The operations of the Company and its subsidiary are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements, including those of the Currency and Foreign Transactions Reporting Act of 1970, as amended, those of the Bank Secrecy Act, as amended by Title III of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act), and the applicable money laundering statutes of all jurisdictions in which the Company and its subsidiary conduct business, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental or regulatory agency (collectively, the “Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or its subsidiary with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

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(cc) No Conflicts with Sanctions Laws. Neither the Company nor its subsidiary, nor any director or officer of the Company or its subsidiary, nor, to the knowledge of the Company, any agent, employee or representative of the Company or its subsidiary, affiliate or other person associated with or acting on behalf of the Company or its subsidiaries is currently the subject or target of any sanctions administered or enforced by the U.S. government (including, without limitation, the Office of Foreign Assets Control of the U.S. Treasury Department or the U.S. Department of State and including, without limitation, the designation as a “specially designated national” or “blocked person”), the United Nations Security Council, the European Union, Her Majesty’s Treasury or other relevant sanctions authority (collectively, “Sanctions”), nor is the Company or its subsidiary located, organized or resident in a country or territory that is the subject or the target of Sanctions, including, without limitation, Cuba, Iran, North Korea, Sudan and Syria (each, a “Sanctioned Country”); and the Company will not directly or indirectly use the proceeds of the offering of the Shares hereunder, or lend, contribute or otherwise make available such proceeds to its subsidiary, any joint venture partner or other person or entity (i) to fund or facilitate any activities of or business with any person that, at the time of such funding or facilitation, is the subject or the target of Sanctions, (ii) to fund or facilitate any activities of or business in any Sanctioned Country or (iii) in any other manner that will result in a violation by any person (including any person participating in the transaction, whether as underwriter, advisor, investor or otherwise) of Sanctions. For the past five years, the Company and its subsidiary have not knowingly engaged in, are not now knowingly engaged in, and will not engage in, any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any Sanctioned Country.

(dd) Taxes. The Company and its subsidiary have filed all federal, state and foreign income and franchise tax returns and have paid all taxes required to be filed or paid by them and, if due and payable, any related or similar assessment, fine or penalty levied against them. The Company has made adequate charges, accruals and reserves in the applicable financial statements referred to in Section 3(j) hereof in respect of all material federal, state and foreign income and franchise taxes for all periods as to which the tax liability of the Company has not been finally determined.

(ee) Insurance. The Company and its subsidiary carry, or are covered by, insurance in such amounts and covering such risks as the Company believes are adequate for the conduct of their business and the value of their properties and is customary for companies engaged in similar industries, and all such insurance is in full force and effect. The Company has no reason to believe that it and its subsidiary. will not be able to (i) renew their existing insurance coverage as and when such policies expire or (ii) obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct their business as currently conducted or proposed to be conducted and at a cost that would not, individually or in the aggregate, result in a Material Adverse Effect. Neither the Company nor its subsidiary has been denied any insurance coverage which it has sought or for which it has applied.

(ff) Benefit Plans. The Company has not maintained or contributed to a defined benefit plan as defined in Section 3(35) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”). No plan maintained or contributed to by the Company that is subject to ERISA (an “ERISA Plan”) (or any trust created thereunder) has engaged in a

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“prohibited transaction” within the meaning of Section 406 of ERISA or Section 4975 of the Internal Revenue Code of 1986, as amended (the “Code”) that could subject the Company to any material tax penalty on prohibited transactions or has not adequately been corrected. Each plan maintained or contributed to by the Company is in compliance in all material respects with all reporting, disclosure and other requirements of the Code and ERISA as they relate to such plan, except for any noncompliance which would not result in the imposition of a material liability or penalty. With respect to each ERISA Plan that is intended to be “qualified” within the meaning of Section 401(a) of the Code, each ERISA Plan has obtained a favorable determination letter or opinion or advisory letter, if applicable as to its qualified status under the Code, each such ERISA Plan has timely adopted all currently effective amendments to the Code to the extent any such amendments are required under the Code, and, to the knowledge of the Company, there are no existing circumstances or any events that have occurred that would affect the qualified status of any such ERISA Plan. The Company has never completely or partially withdrawn from a “multiemployer plan,” as defined in Section 3(37) of ERISA. Each plan maintained or contributed to by the Company that is subject to Section 409A of the Code has been administered in compliance with its terms and the operational and documentary requirements of Section 409A of the Code and the regulations thereunder.

(gg) Title to Intellectual Property. Except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, the Company and its subsidiary own, have valid and enforceable licenses for or otherwise have adequate rights to use technology (including but not limited to patented, patentable and unpatented inventions and unpatentable proprietary or confidential information, systems or procedures), designs, processes, licenses, patents, patent applications, trademarks, service marks, trade and service mark registrations, trade secrets, trade names, know how, copyrights and other works of authorship, computer programs, technical data and information and other intellectual property (collectively, the “Intellectual Property”) that are or would reasonably be expected to be material to their business as currently conducted or as currently proposed to be conducted (including upon the commercialization of products or services described in the Registration Statement, the General Disclosure Package or the Prospectus as under development) or to the development, manufacture, operation and sale of any products and services sold or proposed to be sold by any of the Company or its subsidiary. The Company’s Intellectual Property has not been adjudged by a court of competent jurisdiction invalid or unenforceable in whole or in part. Except as disclosed in the Registration Statement, the General Disclosure Package and the Prospectus, (i) to the knowledge of the Company, there are no third parties who have or, or who will be able to establish rights to any Intellectual Property owned by, or licensed to, the Company or its subsidiary, except for, and to the extent of, the ownership rights of the owners of the Intellectual Property which the Registration Statement, the General Disclosure Package and the Prospectus disclose is licensed to the Company; (ii) to the knowledge of the Company, there is no infringement by third parties of any Intellectual Property owned by, or licensed to, the Company or its subsidiary; (iii) there is no pending or, to the knowledge of the Company, threatened action, suit, proceeding or claim by others challenging the Company’s rights in or to any Intellectual Property owned by, or licensed to, the Company or its subsidiary, and the Company is unaware of any facts which could form a reasonable basis for any such action, suit, proceeding or claim; (iv) there is no pending or, to the knowledge of the Company, threatened action, suit, proceeding or claim by others challenging the validity, enforceability or scope of any Intellectual Property owned by, or licensed to, the Company and its subsidiary, and the Company is unaware

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of any facts which could form a reasonable basis for any such action, suit, proceeding or claim; (v) there is no pending or, to the knowledge of the Company, threatened action, suit, proceeding or claim by others that (nor has the Company received any claim from a third party that) the Company or its subsidiary infringe or otherwise violate, or would, upon the commercialization of any product or service as described in the Registration Statement, the General Disclosure Package or the Prospectus, infringe or otherwise violate, any patent, trademark, tradename, service name, copyright, trade secret or other proprietary rights of another, and the Company and its subsidiary are unaware of any facts which could form a reasonable basis for any such action, suit, proceeding or claim; (vi) to the knowledge of the Company, no employee of the Company is or has been in violation of any term of any employment contract, patent disclosure agreement, invention assignment agreement, non-competition agreement, non-solicitation agreement, nondisclosure agreement or any restrictive covenant to or with a former employer where the basis of such violation relates to such employee’s employment with the Company; (vii) the Company and its subsidiary have complied with the terms of each agreement pursuant to which Intellectual Property has been licensed to the Company and its subsidiary, and all such agreements are in full force and effect; (viii) to the knowledge of the Company, there is no prior art that may render any patent within the Intellectual Property invalid or that may render any patent application within the Intellectual Property unpatentable that has not been disclosed to the U.S. Patent and Trademark Office; and (ix) to the knowledge of the Company, there are no material defects in any of the patents or patent applications within the Intellectual Property. Except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, the Company and its subsidiary are not obligated or under any liability whatsoever to make any material payment by way of royalties, fees or otherwise to any owner or licensee of, or other claimant to, any Intellectual Property, with respect to the use thereof or in connection with the conduct of their respective businesses or otherwise.

(hh) Trademarks. The Company and its subsidiary own, or are licensed or otherwise have the full exclusive right to use, all material trademarks and trade names that are used in or reasonably necessary for the conduct of their business as described in the Prospectus. The Company has not received any notice of infringement of or conflict with asserted rights of others with respect to any such trademarks or trade names, or challenging or questioning the validity or effectiveness of any such trademark or trade name. The use, in connection with the business and operations of the Company and its subsidiary of such trademarks and trade names does not, to the Company’s knowledge, infringe on the rights of any person. Except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus, the Company and its subsidiary are not obligated or under any liability whatsoever to make any payment by way of royalties, fees or otherwise to any owner or licensee of, or other claimant to, any trademark, service mark or trade name with respect to the use thereof or in connection with the conduct of their business or otherwise.

(ii) Protection of Intellectual Property. The Company and its subsidiary have taken reasonable security measures to protect the secrecy, confidentiality and value of all their Intellectual Property in all material aspects, including, but not limited to complying with all duty of disclosure requirements before the U.S. Patent and Trademark Office and any other non-U.S. Patent Offices as appropriate, and has no reason to believe that such Intellectual Property is not or, if not yet patented or registered, would not be, valid and enforceable against an unauthorized user.

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(jj) Related Party Transactions. There are no business relationships or related party transactions involving the Company or any other person required to be described in the General Disclosure Package and the Prospectus that have not been described. Without limiting the generality of the immediately preceding sentence, no relationship, direct or indirect, exists between or among the Company on the one hand, and the directors, officers, stockholders, customers or suppliers of the Company on the other hand, that is required to be described in the General Disclosure Package and the Prospectus and that is not so described. Since inception, the Company has not, directly or indirectly, extended or maintained credit, arranged to extend credit, or renewed any extension of credit, in the form of a personal loan, to or for any director or executive officer of the Company, or to or for any family member or affiliate of any director or executive officer of the Company in violation of applicable laws, including Section 13(k) of the Exchange Act.

(kk) Environmental Matters. Each of the Company and its subsidiary (i) is in compliance with any and all applicable federal, state, local and non-U.S. laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”), (ii) has received all permits, licenses or other approvals required of it under applicable Environmental Laws to conduct its businesses and (iii) is in compliance with all terms and conditions of any such permit, license or approval.

(ll) Controls and Procedures.

(i) Disclosure Controls and Procedures. The Company has established and maintains disclosure controls and procedures (as such term is defined in Rules 13a-15 and 15d-15 under the Exchange Act) that (A) are designed to ensure that material information relating to the Company and its subsidiary is made known to the Company’s principal executive officer and its principal financial officer by others within those entities, particularly during the periods in which the periodic reports required under the Exchange Act are being prepared; (B) provide for the periodic evaluation of the effectiveness of such disclosure controls and procedures as of the end of the period covered by the Company’s most recent annual or quarterly report filed with the Commission; and (C) are effective in all material respects to perform the functions for which they were established.

(ii) Internal Control Over Financial Reporting and Internal Accounting Controls. The Company maintains (i) effective “internal control over financial reporting” as defined in, and in compliance with, Rules 13a-15 and 15d-15 under the Exchange Act, and (ii) a system of internal accounting controls sufficient to provide reasonable assurance that (A) transactions are executed in accordance with management’s general or specific authorizations; (B) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (C) access to assets is permitted only in accordance with management’s general or specific authorization; (D) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences; and (E) the interactive data in eXtensible Business Reporting Language included or incorporated by reference in the Registration Statement, the General Disclosure Package and the Prospecus fairly presents the information called for in all material respects and is prepared in accordance with the Commission’s rules and guidelines applicable thereto.

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(iii) No Material Weakness in Internal Controls. Since the end of the Company’s most recent audited fiscal year, there has been (A) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (B) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting. The Company is not aware of (x) any significant deficiency in the design or operation of its internal control over financial reporting which is reasonably likely to adversely affect the Company’s ability to record, process, summarize and report financial data or any material weaknesses in its internal controls, except as disclosed in the Registration Statement, the General Disclosure Package and the Prospectus, or in any document incorporated by reference therein, since the end of the Company’s most recent audited fiscal year; or (y) any fraud, whether or not material, that involves management or other employees who have a significant role in the Company’s internal controls.

(mm) Off-Balance Sheet Transactions. Except as described in the Registration Statement, the General Disclosure Package and the Prospectus, there are no off-balance sheet transactions (including, without limitation, transactions related to, and the existence of, “variable interest entities” within the meaning of Financial Accounting Standards Board Accounting Standards Codification Topic 810), arrangements, obligations (including contingent obligations), or any other relationships with unconsolidated entities or other persons, that may have a material current or future effect on the Company’s financial condition, changes in financial condition, results of operations, liquidity, capital expenditures, capital resources, or significant components of revenues or expenses.

(nn) Audit Committee. The Company’s Board of Directors has validly appointed an audit committee whose composition satisfies the requirements of Section 10A of, and Rule 10A-3 under, the Exchange Act and the Board of Directors and/or the audit committee has adopted a charter that satisfies the requirements of Section 10A of, and Rule 10A-3 under, the Exchange Act. The audit committee has reviewed the adequacy of its charter. Neither the Board of Directors nor the audit committee has been informed, nor is any director of the Company aware, of (i) any significant deficiency in the design or operation of the Company’s internal control over financial reporting which is reasonably likely to adversely affect the Company’s ability to record, process, summarize and report financial data or any material weakness in the Company’s internal controls; or (ii) any fraud, whether or not material, that involves management or other employees of the Company who have a significant role in the Company’s internal controls.

(oo) Sarbanes-Oxley. The Company is, and after giving effect to the offering and sale of the Shares will be, in compliance in all material respects with all applicable effective provisions of the Sarbanes-Oxley Act of 2002 and the rules and regulations of the Commission promulgated thereunder.

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(pp) Accurate Disclosure. The statements included in the Registration Statement, the General Disclosure Package and the Prospectus (including those contained in any document incorporated by reference therein) under the captions “Material U.S. Federal Income Tax Considerations for Non-U.S. Holders,” “Description of Capital Stock,” “Shares Eligible for Future Sale,” and “Underwriting,” and the statements in the Registration Statement under Items 14 and 15 thereof, insofar as such statements contain descriptions of the terms of statutes, rules, regulations or legal or governmental proceedings, or contracts or other documents, are fair and accurate in all material respects.

(qq) Data Presentation. The preclinical studies and clinical trials conducted by or on behalf of the Company that are described in the Registration Statement, General Disclosure Package and the Prospectus (the “Company Studies”) were and, if still pending, are being, conducted in all material respects in accordance with their experimental protocols; the descriptions of the results of the Company Studies contained in the Registration Statement, General Disclosure Package and the Prospectus are accurate in all material respects; the Company has no knowledge of any other preclinical studies or clinical trials not described in the Registration Statement, General Disclosure Package and the Prospectus the results of which are inconsistent with or otherwise call into question the results described or referred to in the Registration Statement, General Disclosure Package and the Prospectus; and the Company has not received any written notices or correspondence from the FDA or any foreign, state or local governmental body exercising comparable authority (the “Regulatory Agencies”) requiring the termination, suspension or material modification of any Company Studies that would reasonably be expected to have a Material Adverse Effect and, to the Company’s knowledge, there are no reasonable grounds for the same. To the Company’s knowledge, none of the Company Studies involved any investigator who has been disqualified as a clinical investigator or has been found by the FDA to have engaged in scientific misconduct.

(rr) Regulatory Filings. The Company has not failed to file with the Regulatory Agencies any required filing, declaration, listing, registration, report or submission with respect to the Company’s product candidates that are described or referred to in the Registration Statement, the General Disclosure Package or the Prospectus or any other filing required by any other applicable Regulatory Agency or governmental authority; all such filings, declarations, listings, registrations, reports or submissions were in material compliance with applicable laws when filed; all such filings, declarations, listings, registrations, reports or submissions were timely, complete, accurate and not misleading on the date filed in all material respects (or were corrected or supplemented by subsequent submission); and no deficiencies regarding compliance with applicable law have been asserted by any applicable Regulatory Agency or other governmental authority with respect to any such filings, declarations, listings, registrations, reports or submissions.

(ss) Licenses and Permits. Except as would not, individually or in the aggregate, have a Material Adverse Effect, (i) the Company and its subsidiary hold, and are operating in compliance with, such permits, licenses, franchises, registrations, exemptions, approvals, authorizations and clearances of any other governmental authorities (including, without limitation, the FDA) required for the conduct of its business as currently conducted (collectively, the “Permits”), and all such Permits are in full force and effect; and (ii) the Company and its subsidiary have fulfilled and performed all of their obligations with respect to the Permits, and, to the Company’s knowledge, no event has occurred which allows, or after notice or lapse of time would allow, revocation or termination thereof or results in any other

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impairment of the rights of the holder of any Permit. All applications, notifications, submissions, information, claims, reports and statistics, and other data and conclusions derived therefrom, utilized as the basis for any and all requests for a Permit from the FDA or other governmental authority relating to the Company or its subsidiary, its business and its products, when submitted to the FDA or other governmental authority by or on behalf of the Company or its subsidiary, were true, complete and correct in all material respects. Any necessary or required updates, changes, corrections or modification to such applications, notifications, submissions, information, claims, reports and statistics and other data have been submitted to the FDA or other governmental authority, except as would not, individually or in the aggregate, have a Material Adverse Effect. The Company and its subsidiary have not received any notification, correspondence or any other written communication, including notification of any pending or, to the Company’s knowledge, threatened claim, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any governmental authority, including, without limitation, the FDA, of potential or actual material non-compliance by, or material liability of, the Company or its subsidiary under any Permits. To the Company’s knowledge, there are no facts or circumstances that would reasonably be expected to give rise to any material liability of the Company or its subsidiary under any Permits.

(tt) Compliance with Certain Regulatory Matters. The Company, its subsidiary, its directors and officers and, to the Company’s knowledge, its employees and agents have operated and currently are in compliance in all material respects with applicable Health Care Laws. For purposes of this Agreement, “Health Care Laws” includes, without limitation: the federal Anti-kickback Statute (42 U.S.C. § 1320a-7b(b)); the Federal Food, Drug, and Cosmetic Act (21 U.S.C. §§ 301 et seq.); the regulations promulgated pursuant to such laws; and any other applicable local, state or federal law or regulation. Neither the Company nor its subsidiary, are a party to, and do not have any ongoing reporting obligations pursuant to, any corporate integrity agreement, deferred prosecution agreement, monitoring agreement, consent decree, settlement order, plan of correction or similar agreement imposed by any governmental authority. Neither the Company, its subsidiary, nor, to the knowledge of the Company, any of their respective directors, officers, employees or agents has been debarred, excluded or suspended from participation in or receiving payment from any federal, state or local government health care program or is subject to an audit, investigation, proceeding, or other similar action by any governmental authority that could reasonably be expected to result in debarment, suspension or exclusion.

(uu) Absence of Certain Regulatory Actions. Except as described in the Registration Statement, the General Disclosure Package and the Prospectus, or as would not, individually or in the aggregate, have a Material Adverse Effect, the Company and its subsidiary, have not had any product or manufacturing site (whether Company-owned or that of a contract manufacturer for Company product candidates) subject to a governmental authority (including, without limitation, the FDA) shutdown or import or export prohibition, nor have the Company and its subsidiary received any FDA Form 483 or other governmental authority notice of inspectional observations, “warning letters,” “untitled letters,” requests to make changes to the Company products, processes or operations, or similar correspondence or notice from the FDA or other governmental authority alleging or asserting material noncompliance with any applicable laws. To the Company’s knowledge, neither the FDA nor any other governmental authority has threatened such action. Neither the Company nor its subsidiary, has received

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written notice of any claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any court, arbitrator, Regulatory Agency, or other governmental authority or third party alleging that any product operation or activity is in violation of any Health Care Laws nor, to the Company’s knowledge, is any such claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action threatened.

(vv) Emerging Growth Company Status. From the time of initial confidential submission of the registration statement relating to the Company’s initial public offering to the Commission (or, if earlier, the first date on which the Company engaged directly or through any Person authorized to act on its behalf in any Testing-the-Waters Communication) through the date hereof, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the Act (an “Emerging Growth Company”).

(ww) Testing-the-Waters Communications. The Company (i) has not engaged in any Testing-the-Waters Communication and (ii) has not authorized anyone to engage in Testing-the-Waters Communications. The Company has not distributed or approved for distribution any Written Testing-the-Waters Communications.

(xx) Confidential Submission of Registration Statement. The Company has filed publicly on EDGAR at least 48 hours prior to the requested effective time and date, any confidentially submitted registration statement and registration statement amendments relating to the offer and sale of the Shares.

(yy) No Rating. Neither the Company nor its subsidiary, has debt securities or preferred stock that is rated by any “nationally recognized statistical rating organization” (as such term is defined in Section 3(a)(62) of the Exchange Act).

(zz) No Broker’s Fees. The Company is not a party to any contract, agreement or understanding with any person (other than this Agreement) that would give rise to a valid claim against the Company or any Underwriter for a brokerage commission, finder’s fee or like payment in connection with the offering and sale of the Shares.

(aaa) Required Filings. The Company has timely made all filings required to be made by it under the Exchange Act.

4. Agreements of the Company. The Company agrees with each Underwriter as follows:

(a) Amendments and Supplements to Registration Statement. The Company shall not, either prior to any effective date or thereafter during such period as the Prospectus is required by law to be delivered (whether physically or through compliance with Rule 172 of the Rules and Regulations or any similar rule) (the “Prospectus Delivery Period”) in connection with sales of the Shares by an Underwriter or dealer, amend or supplement the Registration Statement, the General Disclosure Package or the Prospectus, unless a copy of such amendment or supplement thereof shall first have been submitted to the Representatives within a reasonable period of time prior to the filing or, if no filing is required, the use thereof and the Representatives shall not have objected thereto in good faith.

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(b) Amendments and Supplements to the Registration Statement, the General Disclosure Package, and the Prospectus and Other Securities Act Matters. If, during the Prospectus Delivery Period, any event or development shall occur or condition exist as a result of which the General Disclosure Package or the Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances then prevailing or under which they were made, as the case may be, not misleading, or if it shall be necessary to amend or supplement the General Disclosure Package or the Prospectus in order to make the statements therein, in the light of the circumstances then prevailing or under which they were made, as the case may be, not misleading, or if in the reasonable opinion of the Representatives it is otherwise necessary to amend or supplement the Registration Statement, the General Disclosure Package or the Prospectus, or to file a new registration statement containing the Prospectus, in order to comply with law, including in connection with the delivery of the Prospectus, the Company agrees to (i) promptly notify the Representatives of any such event or condition and (ii) promptly prepare (subject to Section 4(a) and 4(f) hereof), file with the Commission (and use its best efforts to have any amendment to the Registration Statement or any new registration statement to be declared effective) and furnish at its own expense to the Underwriters (and, if applicable, to dealers), amendments or supplements to the Registration Statement, the General Disclosure Package or the Prospectus, or any new registration statement, necessary in order to make the statements in the General Disclosure Package or the Prospectus as so amended or supplemented, in the light of the circumstances then prevailing or under which they were made, as the case may be, not misleading or so that the Registration Statement, the General Disclosure Package or the Prospectus, as amended or supplemented, will comply with law.

(c) Notifications to the Representatives. The Company shall use its best efforts to cause the Registration Statement to become effective, and shall notify the Representatives promptly in writing, (i) when any post-effective amendment to the Registration Statement has become effective and when any post-effective amendment thereto becomes effective, (ii) of any request by the Commission for amendments or supplements to the Registration Statement or the Prospectus or for additional information, (iii) of the commencement by the Commission or by any state securities commission of any proceedings for the suspension of the qualification of any of the Shares for offering or sale in any jurisdiction or of the initiation, or the threatening, of any proceeding for that purpose, including, without limitation, the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or the initiation of any proceedings for that purpose or the threat thereof, (iv) of the happening of any event during the Prospectus Delivery Period that in the judgment of the Company makes any statement made in the Registration Statement or the Prospectus untrue or that requires the making of any changes in the Registration Statement or the Prospectus in order to make the statements therein, in light of the circumstances in which they are made, not misleading (v) of receipt by the Company or any representative of the Company of any other communication from the Commission relating to the Company, the Registration Statement, any preliminary prospectus or the Prospectus and (vi) of any distribution of Written Testing-the-Waters Communication by or on behalf of the Company (other than through any Underwriter). If at any time the Commission shall issue any order suspending the effectiveness of the Registration Statement, the Company shall use best efforts to obtain the withdrawal of such order at the earliest possible moment. The Company shall comply with the provisions of and make all requisite filings with the Commission pursuant to Rules 424(b), 430A, 430B, 430C and 462(b) of the Rules and Regulations and notify the Representatives promptly of all such filings.

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(d) Executed Registration Statement. Upon request of the Representatives, to the extent not available on EDGAR, the Company shall furnish to the Representatives, without charge, for transmittal to each of the other Underwriters, two signed copies of the Registration Statement and of any post-effective amendment thereto, including financial statements and schedules, and all exhibits thereto, and shall furnish to the Representatives, without charge, for transmittal to each of the other Underwriters, a copy of the Registration Statement and any post-effective amendment thereto, including financial statements and schedules but without exhibits.

(e) Undertakings. The Company shall comply with all the provisions of any undertakings contained and required to be contained in the Registration Statement.

(f) Prospectus. The Company shall prepare the Prospectus in a form approved by the Representatives and shall file such Prospectus pursuant to Rule 424(b) of the Rules and Regulations with a filing date not later than the second business day following the execution and delivery of this Agreement. Promptly after the effective date of the Registration Statement, and thereafter from time to time, the Company shall deliver to each of the Underwriters, without charge, as many copies of the Prospectus and any amendment or supplement thereto as the Representatives may reasonably request. The Company consents to the use of the Prospectus and any amendment or supplement thereto by the Underwriters and by all dealers to whom the Shares may be sold, both in connection with the offering or sale of the Shares and for any period of time thereafter during the Prospectus Delivery Period. If, during the Prospectus Delivery Period any event shall occur that in the judgment of the Company or counsel to the Underwriters should be set forth in the Prospectus in order to make any statement therein, in the light of the circumstances under which it was made, not misleading, or if it is necessary to supplement or amend the Prospectus to comply with law, the Company shall forthwith prepare and duly file with the Commission an appropriate supplement or amendment thereto, and shall deliver to each of the Underwriters, without charge, such number of copies thereof as the Representatives may reasonably request.

(g) Permitted Free Writing Prospectuses. The Company represents and agrees that it has not made and, unless it obtains the prior consent of the Representatives, will not make, any offer relating to the Shares that would constitute a “free writing prospectus” as defined in Rule 405 of the Rules and Regulations, required to be filed with the Commission or retained by the Company under Rule 433 of the Rules and Regulations; provided that the prior written consent of the Representatives hereto shall be deemed to have been given in respect of the Issuer Free Writing Prospectuses included in Schedule II hereto. Any such free writing prospectus consented to by the Representatives is herein referred to as a “Permitted Free Writing Prospectus.” The Company agrees that (i) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus, and (ii) has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 of the Act applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

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(h) Compliance with Blue Sky Laws. Prior to any public offering of the Shares by the Underwriters, the Company shall cooperate with the Representatives and counsel to the Underwriters in connection with the registration or qualification (or the obtaining of exemptions from the application thereof) of the Shares for offer and sale under the securities or Blue Sky laws of such jurisdictions as the Representatives may request, including, without limitation, the provinces and territories of Canada and other jurisdictions outside the United States; provided, however, that in no event shall the Company be obligated to qualify to do business in any jurisdiction where it is not now so qualified or to take any action which would subject it to general service of process in any jurisdiction where it is not now so subject.

(i) Delivery of Financial Statements. During the period of five years commencing on the effective date of the Registration Statement applicable to the Underwriters, the Company shall furnish to the Representatives and each other Underwriter who may so request copies of such financial statements and other periodic and special reports as the Company may from time to time distribute generally to the holders of any class of its capital stock, and will furnish to the Representatives and each other Underwriter who may so request a copy of each annual or other report it shall be required to file with the Commission; provided, however, that electronically transmitted copies filed with the Commission pursuant to EDGAR shall satisfy the Company’s obligation to furnish copies hereunder.

(j) Availability of Earnings Statements. The Company shall make generally available to holders of its securities as soon as may be practicable but in no event later than the last day of the fifteenth full calendar month following the calendar quarter in which the most recent effective date occurs in accordance with Rule 158 of the Rules and Regulations, an earnings statement (which need not be audited but shall be in reasonable detail) for a period of 12 months ended commencing after the effective date of the Registration Statement, and satisfying the provisions of Section 11(a) of the Act (including Rule 158 of the Rules and Regulations).

(k) Payment of Expenses. Whether or not any of the transactions contemplated by this Agreement are consummated or this Agreement is terminated, the Company will pay or cause to be paid, or reimburse if paid by the Representatives, all costs and expenses incident to the performance of the obligations of the Company under this Agreement, including but not limited to: (i) any filing fees and other expenses (including reasonable and documented fees and disbursements of counsel to the Underwriters) incurred in connection with qualification of the Shares for sale under the laws of such jurisdictions as the Representatives designate pursuant to Section 4(g) hereof and the securities laws of Canada, including the reasonable and documented fees, disbursements and other charges of counsel to the Underwriters in connection therewith, and, if requested by the Representatives, the preparation and printing of preliminary, supplemental and final Blue Sky memoranda, collectively not to exceed $5,000, (ii) the preparation and printing of memoranda relating thereto, costs and expenses related to the review by FINRA of the Shares (including filing fees and the fees and expenses of counsel for the Underwriters relating to such review), collectively not to exceed $35,000, (iii) costs and expenses relating to investor presentations or any “road show” in connection with the offering and sale of the Shares including, without limitation, the travel expenses of the Company’s officers, employees and agents and 50% of the cost of chartering aircraft in connection with any “road show,” such aircraft not to be chartered without the written consent of the Company (the

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remaining 50% of the cost of such aircraft shall be paid by the Underwriters), (iv) fees and expenses incident to listing the Shares on the NASDAQ Global Select Market, (v) fees and expenses in connection with the registration of the Shares under the Exchange Act, (vi) expenses incurred in distributing preliminary prospectuses and the final prospectus (including any amendments and supplements thereto) to the Underwriters, (vii) for expenses incurred for preparing, printing and distributing any Issuer Free Writing Prospectuses to investors or prospective investors, (viii) the fees and expenses of counsel to the Company, (ix) the costs and charges of DTC and the transfer agent for the Shares and (x) the fees and expenses of the Accountants.

(l) Reimbursement of Expenses upon Termination of Agreement. If this Agreement shall be terminated by the Company pursuant to any of the provisions hereof or if for any reason the Company shall be unable to perform its obligations or to fulfill any conditions hereunder or if the Underwriters shall terminate this Agreement pursuant to Section 7 hereof or the Agreement is terminated pursuant to the second sentence of Section 8 hereof, (A) the Company shall reimburse the Underwriters for all reasonable and documented out-of-pocket expenses (including the documented fees, disbursements and other charges of counsel to the Underwriters) reasonably incurred by them in connection herewith; and (B) if such termination is after the Closing Date, with respect to the proposed purchase of any Option Shares pursuant to a notice delivered by the Underwriters to the Company, the Company shall reimburse the Underwriters for the reasonable and documented fees and expenses of Underwriters’ counsel and for such other out-of-pocket expenses, such fees and expenses collectively not to exceed $50,000, as shall have been reasonably and actually incurred by them following the Closing Date pursuant to this Agreement in connection with such proposed purchase of such Option Shares; provided, however, that the Company shall not be obligated to reimburse the expenses of any defaulting Underwriter under Section 8 hereof.

(m) No Stabilization or Manipulation. The Company shall not at any time, directly or indirectly, take any action intended to cause or result in, or which would reasonably be expected to cause or result in, or which will constitute, stabilization or manipulation, under the Act or otherwise, of the price of the shares of Common Stock to facilitate the sale or resale of any of the Shares.

(n) Use of Proceeds. The Company shall apply the net proceeds from the offering and sale of the Shares to be sold by the Company in the manner set forth in the General Disclosure Package and the Prospectus under “Use of Proceeds”.

(o) Lock-Up Agreements of Company, Management and Affiliates. The Company shall not, for a period of 90 days after the date of the Prospectus (the “Lock-Up Period”), without the prior written consent of Credit Suisse Securities (USA) LLC (which consent may be withheld in its sole discretion), (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, or file with the Commission a registration statement under the Act to register, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (2) enter into any swap or other derivatives transaction that transfers to another, in whole or in part, directly or indirectly, any of the economic benefits or risks of ownership of such shares of

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Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or other securities, in cash or otherwise, or publicly disclose the intention to enter into any transaction described in clause (1) or (2) above. The foregoing sentence shall not apply to (A) the Shares to be sold hereunder; (B) any shares of Common Stock issued by the Company upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof and referred to in the Registration Statement, General Disclosure Package and the Prospectus; (C) any shares of Common Stock issued by the Company upon the exercise of an option to purchase Common Stock granted pursuant to employee stock option plans or stock ownership plans of the Company in effect on the date hereof and described in the Registration Statement, General Disclosure Package and the Prospectus (but for the avoidance of doubt, not any sale of such shares issued upon such exercise); (D) entry into agreements providing for the issuance by the Company of shares of Common Stock or any security convertible into or exercisable for shares of Common Stock in connection with the acquisition by the Company or its subsidiary of the securities, business, property or other assets of another person or entity pursuant to an employee benefit plan assumed by the Company in connection with such acquisition, and issue any such securities pursuant to any such agreement; (E) entry into agreements providing for the issuance of shares of Common Stock or any security convertible into or exercisable for shares of Common Stock in connection with joint ventures, commercial relationships or other strategic transactions, and the issuance of any such securities pursuant to any such agreements; provided that in the case of clauses (D) and (E), the aggregate number of shares of Common Stock that the Company may sell or issue or agree to sell or issue pursuant to clauses (D) and (E), taken together, shall not exceed 5.0% of the total number of shares of Common Stock issued and outstanding immediately subsequent to the completion of the transactions contemplated by this Agreement; provided further that in the case of clauses (D) and (E), it shall be a condition to the sale, issuance or transfer of shares of any such securities that the transferee executes and delivers to the Representatives, acting on behalf of the Underwriters, not later than one business day prior to such transfer, a written agreement, in substantially the form of Exhibit A to this Agreement, and otherwise satisfactory in form and substance to the Representatives; (F) the filing of or amendment to a registration statement on Form S-8 under the Securities Act to register the offer and sale of securities to be issued pursuant to any employee benefit or equity incentive plan of the Company in effect on the date hereof and that is described in the Registration Statement, General Disclosure Package and the Prospectus, and issuance of securities pursuant to any such employee benefit or equity incentive plan (including, without limitation, the issuance of shares of Common Stock upon the exercise of options or other securities issued pursuant to such employee benefit or equity incentive plan), provided that (1) this clause (F) shall not be available unless each executive officer or director recipient of shares of Common Stock, or securities exchangeable or exercisable for or convertible into Common Stock, pursuant to any such employee benefit or equity incentive plan shall be contractually prohibited from selling, offering, disposing of or otherwise transferring any such shares or securities during the remainder of the Lock-Up Period. The Company shall cause each of its executive officers and directors and their affiliated entities to enter into agreements with the Representatives in the form set forth in Exhibit A.

(p) Emerging Growth Company Status. The Company shall promptly notify the Representatives if the Company ceases to be an Emerging Growth Company at any time prior to the later of (x) the time when a prospectus relating to the offering or sale of the Shares is not required by the Act to be delivered (whether physically or through compliance with Rule 172 of the Rules and Regulations or any similar rule) and (B) completion of the Lock-Up Period.

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(q) Transfer Agent. The Company shall maintain, at its expense, a registrar and transfer agent for the Shares.

(r) Listing. The Company will maintain the listing of the Shares on the Nasdaq Global Select Market.

5. Conditions of the Obligations of the Underwriters. The obligation of each Underwriter to purchase the Firm Shares on the Closing Date or the Option Shares on the Option Closing Date, as the case may be, as provided herein is subject to the performance by the Company of its covenants and other obligations hereunder and to the following additional conditions:

(a) Post Effective Amendments and Prospectus Filings. Notification that the Registration Statement has become effective shall be received by the Representatives not later than 6:00 p.m., New York City time, on the date of this Agreement or at such later date and time as shall be consented to in writing by the Representatives and all filings made pursuant to Rules 424, 430A, 430B or 430C of the Rules and Regulations, as applicable, shall have been made or will be made prior to the Closing Date in accordance with all such applicable rules.

(b) No Stop Orders, Requests for Information and No Amendments. (i) No stop order suspending the effectiveness of the Registration Statement shall have been issued and no proceedings for that purpose shall be pending or are, to the knowledge of the Company, threatened by the Commission, (ii) no order suspending the qualification or registration of the Shares under the securities or Blue Sky laws of any jurisdiction shall be in effect and no proceeding for such purpose shall be pending before or threatened or contemplated by the authorities of any such jurisdiction, (iii) any request for additional information on the part of the staff of the Commission or any such authorities shall have been complied with to the satisfaction of the staff of the Commission or such authorities and (iv) after the date hereof no amendment or supplement to the Registration Statement or the Prospectus shall have been filed unless a copy thereof was first submitted to the Representatives and the Representatives did not object thereto in good faith, and the Representatives shall have received certificates, dated the Closing Date and the Option Closing Date and signed by the Chief Executive Officer or the Chairman of the Board of Directors and the Chief Financial Officer of the Company (who may, as to proceedings threatened, rely upon the best of their information and belief), to the effect of clauses (i), (ii) and (iii).

(c) No Material Adverse Changes. Since the respective dates as of which information is given in the Registration Statement and the Prospectus, except as set forth in the Registration Statement, the General Disclosure Package and the Prospectus (i) there shall not have been a Material Adverse Change, (ii) the Company shall not have incurred any material liabilities or obligations, direct or contingent, (iii) the Company shall not have entered into any material transactions not in the ordinary course of business other than pursuant to this Agreement and the transactions referred to herein, (iv) the Company shall not have issued any securities (other than the Shares) or declared or paid any dividend or made any distribution in respect of its capital stock of any class or debt (long-term or short-term), and (v) no material amount of the assets of the Company shall have been pledged, mortgaged or otherwise encumbered.

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(d) No Actions, Suits or Proceedings. Since the respective dates as of which information is given in the Registration Statement, the General Disclosure Package and the Prospectus, there shall have been no actions, suits or proceedings instituted, or to the Company’s knowledge, threatened against or affecting, the Company or any of its officers in their capacity as such, before or by any Federal, state or local court, commission, regulatory body, administrative agency or other governmental body, domestic or foreign, except as would not reasonably be expected to have a Material Adverse Effect.

(e) All Representations True and Correct and All Conditions Fulfilled. Each of the representations and warranties of the Company contained herein shall be true and correct at the Closing Date as if made at the Closing Date and, with respect to the Option Shares, at the Option Closing Date as if made at the Option Closing Date, and all covenants and agreements contained herein to be performed by the Company and all conditions contained herein to be fulfilled or complied with by the Company at or prior to the Closing Date and, with respect to the Option Shares, at or prior to the Option Closing Date, shall have been duly performed, fulfilled or complied with.

(f) Opinions of Counsel to the Company. The Representatives shall have received the opinions and letters, each dated the Closing Date and, with respect to the Option Shares, the Option Closing Date, reasonably satisfactory in form and substance to counsel for the Underwriters, from Fenwick & West LLP, counsel to the Company, to the effect set forth in Exhibit B, Leydig, Voit & Mayer, Ltd., intellectual property counsel to the Company, to the effect set forth in Exhibit C, Hyman, Phelps & McNamara P.C., regulatory counsel to the Company, to the effect set forth in Exhibit D, and Griffith Hack, local regulatory counsel to the Company, to the effect set forth in Exhibit E.

(g) Opinion of Counsel to the Underwriters. The Representatives shall have received an opinion, dated the Closing Date and the Option Closing Date, from Cooley LLP, counsel to the Underwriters, with respect to the Registration Statement, the Prospectus and this Agreement, which opinion shall be satisfactory in all respects to the Representatives.

(h) Accountants’ Comfort Letter. On the date of the Prospectus, the Representatives shall have received from the Accountants a letter dated the date of its delivery, addressed to the Representatives, in form and substance reasonably satisfactory to the Representatives, containing statements and information of the type ordinarily included in accountant’s “comfort letters” to underwriters, delivered according to Statement of Auditing Standards No. 72 (or any successor bulletin), with respect to the audited and unaudited financial statements and certain financial information contained in the Registration Statement and the Prospectus. At the Closing Date and, as to the Option Shares, the Option Closing Date, the Representatives shall have received from the Accountants a letter dated such date, in form and substance reasonably satisfactory to the Representatives, to the effect that they reaffirm the statements made in the letter furnished by them pursuant to the preceding sentence and have conducted additional procedures with respect to certain financial figures included in the Prospectus, except that the specified date referred to therein for the carrying out of procedures shall be no more than three business days prior to the Closing Date or the Option Closing Date, as applicable.

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(i) Chief Financial Officer Certificate. At the time of execution of this Agreement and at the Closing Date and, as to the Option Shares, the Option Closing Date, there shall be furnished to the Representatives an accurate certificate, dated the date of its delivery, signed by the Chief Financial Officer of the Company, in form and substance satisfactory to the Representatives.

(j) Officers’ Certificates. At the Closing Date and, as to the Option Shares, the Option Closing Date, there shall be furnished to the Representatives an accurate certificate, dated the date of its delivery, signed by each of the Chief Executive Officer and the Chief Financial Officer of the Company, in form and substance satisfactory to the Representatives, to the effect that:

(i) each signer of such certificate has carefully examined the Registration Statement and the Prospectus;

(ii) there has not been a Material Adverse Change;

(iii) no stop order suspending the effectiveness of the Registration Statement has been issued; and no proceedings or examination for that purpose have been instituted or, to the knowledge of such signer, threatened;

(iv) each of the representations and warranties of the Company contained in this Agreement are, at the time such certificate is delivered, true and correct; and

(v) each of the covenants required herein to be performed by the Company on or prior to the date of such certificate has been duly, timely and fully performed and each condition herein required to be complied with by the Company on or prior to the delivery of such certificate has been duly, timely and fully complied with.

(k) Lock-Up Agreements. At the date of this Agreement, the Representatives shall have received the executed “lock-up” agreements referred to in Section 4(o) hereof from the Company’s executive officers and directors and their affiliated entities.

(l) Compliance with Blue Sky Laws. The Shares shall be qualified for sale in such states and jurisdictions as the Representatives may reasonably request, including, without limitation, the provinces and territories of Canada and other jurisdictions outside the United States, and each such qualification shall be in effect and not subject to any stop order or other proceeding on the Closing Date and the Option Closing Date.

(m) Stock Exchange Listing. The Shares shall have been duly authorized for listing or quotation on the NASDAQ Global Select Market, subject only to notice of issuance.

(n) Good Standing. At the Closing Date and the Option Closing Date, the Company shall have furnished to the Representatives satisfactory evidence of the good standing of the Company and, if applicable, its subsidiary in their respective jurisdictions of organization and their good standing as foreign entities in such other jurisdictions as the Representatives may reasonably request, in each case in writing or any standard form of telecommunication from the appropriate governmental authorities of such jurisdictions

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(o) Company Certificates. The Company shall have furnished to the Representatives such certificates, in addition to those specifically mentioned herein, as the Representatives may have reasonably requested as to the accuracy and completeness at the Closing Date and the Option Closing Date of any statement in the Registration Statement or the Prospectus, as to the accuracy at the Closing Date and the Option Closing Date of the representations and warranties of the Company herein, as to the performance by the Company of its obligations hereunder, or as to the fulfillment of the conditions concurrent and precedent to the obligations hereunder of the Underwriters.

(n) No Objection. FINRA has confirmed that it has not raised any objection with respect to the fairness and reasonableness of the underwriting terms and arrangements relating to the offering of the Shares.

If any of the conditions hereinabove provided for in this Section 5 shall not have been fulfilled when and as required by this Agreement to be fulfilled, the obligations of the Underwriters hereunder may be terminated by the Representatives by notifying the Company of such termination in writing at or prior to the Closing Date or the Option Closing Date, as the case may be

6. Indemnification.

(a) Indemnification of the Underwriters. The Company will indemnify and hold harmless each Underwriter, its partners, members, directors, officers, employees, agents, affiliates and each person, if any, who controls such Underwriter within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each an “Indemnified Party”), against any and all losses, claims, damages or liabilities, joint or several, to which such Indemnified Party may become subject, under the Act, the Exchange Act, other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any part of any Registration Statement at any time (or any amendment thereto), including any information deemed to be a part thereof pursuant to Rules 430A, 430B or 430C, any preliminary prospectus, any preliminary prospectus supplement, any Issuer Free Writing Prospectus, the Prospectus or any Written Testing-the-Waters Communication, any materials or information provided to investors by, or with the approval of, the Company in connection with the marketing of the offering of the Shares, including any roadshow or investor presentations made to investors by the Company (whether in person or electronically) or arise out of or are based upon the omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse each Indemnified Party for any documented legal or other expenses reasonably incurred by such Indemnified Party in connection with investigating or defending against any loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Indemnified Party is a party thereto), whether threatened or commenced, and in connection with the enforcement of this provision with respect to any of the above as such expenses are incurred; provided, however, that

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the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement in or omission or alleged omission from any of such documents in reliance upon and in conformity with written information furnished to the Company by any Underwriter specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the Underwriters’ Information. This indemnity agreement will be in addition to any liability that the Company might otherwise have.

(b) Indemnification of the Company. Each Underwriter will severally and not jointly indemnify and hold harmless the Company, each of its directors and each of its officers who signs a Registration Statement and each person, if any, who controls the Company within the meaning of Section 15 of the Act or Section 20 of the Exchange Act (each, an “Underwriter Indemnified Party”) against any losses, claims, damages or liabilities to which such Underwriter Indemnified Party may become subject, under the Act, the Exchange Act, or other Federal or state statutory law or regulation or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in any part of any Registration Statement at any time (or any amendment thereto) , including any information deemed to be a part thereof pursuant to Rules 430A, 430B or 430C, any preliminary prospectus, any preliminary prospectus supplement, any Issuer Free Writing Prospectus, the Prospectus or any Written Testing-the-Waters Communication or arise out of or are based upon the omission or the alleged omission of a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in reliance upon and in conformity with written information furnished to the Company by such Underwriter through the Representatives specifically for use therein, and will reimburse any legal or other expenses reasonably incurred by such Underwriter Indemnified Party in connection with investigating or defending against any such loss, claim, damage, liability, action, litigation, investigation or proceeding whatsoever (whether or not such Underwriter Indemnified Party is a party thereto), whether threatened or commenced, based upon any such untrue statement or omission, or any such alleged untrue statement or omission as such expenses are incurred, it being understood and agreed that the only such information furnished by any Underwriter consists of Underwriters’ Information. This indemnity will be in addition to any liability that each Underwriter might otherwise have.

(c) Actions against Parties; Notification. Promptly after receipt by an indemnified party under this Section 6 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under Section 6(a) or 6(b) above, notify the indemnifying party of the commencement thereof; but the failure to notify the indemnifying party shall not relieve it from any liability that it may have under Section 6(a) or 6(b) above except to the extent that it has been materially prejudiced (through the forfeiture of substantive rights or defenses) by such failure; and provided further that the failure to notify the indemnifying party shall not relieve it from any liability that it may have to an indemnified party otherwise than under Section 6(a) or 6(b) above. In case any such action is brought against any indemnified party and it notifies an indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate therein and, to the extent that it may wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the

- 29 -

consent of the indemnified party, be counsel to the indemnifying party), and after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party will not be liable to such indemnified party under this Section 6 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof other than reasonable costs of investigation. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened action in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party unless such settlement (i) includes an unconditional release of such indemnified party from all liability on any claims that are the subject matter of such action and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act by or on behalf of an indemnified party.

(d) Contribution. If the indemnification provided for in this Section 6 is unavailable or insufficient to hold harmless an indemnified party under Section 6(a) or 6(b) above, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of the losses, claims, damages or liabilities referred to in Section 6(a) or 6(b) above (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other from the offering of the Shares or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total underwriting discounts and commissions received by the Underwriters. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The amount paid by an indemnified party as a result of the losses, claims, damages or liabilities referred to in the first sentence of this Section 6(d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any action or claim which is the subject of this Section 6(d). Notwithstanding the provisions of this Section 6(d), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations in this Section 6(d) to contribute are several in proportion to their respective underwriting obligations and not joint. The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 6(d) were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in this Section 6(d).

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(e) Survival. The indemnity and contribution agreements contained in this Section 6 and the representations and warranties of the Company contained in this Agreement shall remain operative and in full force and effect regardless of (i) any investigation made by or on behalf of the Underwriters, (ii) acceptance of any of the Shares and payment therefor or (iii) any termination of this Agreement.

7. Termination. The obligations of the several Underwriters under this Agreement may be terminated at any time prior to the Closing Date (or, with respect to the Option Shares, on or prior to the Option Closing Date), by notice to the Company from the Representatives, without liability on the part of any Underwriter to the Company, if, prior to delivery and payment for the Firm Shares (or the Option Shares, as the case may be), in the sole judgment of the Representatives, any of the following shall occur:

(a) trading or quotation in any of the equity securities of the Company shall have been suspended or limited by the Commission or by an exchange or otherwise;

(b) trading in securities generally on the New York Stock Exchange, the NASDAQ Global Market or the NASDAQ Global Select Market shall have been suspended or limited or minimum or maximum prices shall have been generally established on such exchange, or additional material governmental restrictions, not in force on the date of this Agreement, shall have been imposed upon trading in securities generally by such exchange or by order of the Commission or any court or other governmental authority;

(c) a general banking moratorium shall have been declared by any of Federal, New York or Delaware authorities;

(d) the United States shall have become engaged in new hostilities, there shall have been an escalation in hostilities involving the United States or there shall have been a declaration of a national emergency or war by the United States or there shall have occurred such a material adverse change in general economic, political or financial conditions, including, without limitation, as a result of terrorist activities after the date hereof (or the effect of international conditions on the financial markets in the United States shall be such), or any other calamity or crisis shall have occurred, the effect of any of which is such as to make it impracticable or inadvisable to market the Shares on the terms and in the manner contemplated by the Prospectus;

(e) the Company shall have sustained a loss material or substantial to the Company by reason of flood, fire, accident, hurricane, earthquake, theft, sabotage, or other calamity or malicious act, whether or not such loss shall have been insured, the effect of any of which is such as to make it impracticable or inadvisable to market the Shares on the terms and in the manner contemplated by the Prospectus; or

(f) there shall have been a Material Adverse Change.

8. Default of Underwriters. If any Underwriter or Underwriters default in their obligations to purchase Shares hereunder on either the Closing Date or any Option Closing Date and the aggregate number of shares of Shares that such defaulting Underwriter or Underwriters agreed but failed to purchase does not exceed 10% of the total number of shares of Shares that the

- 31 -

Underwriters are obligated to purchase on such Closing Date, the Representatives may make arrangements satisfactory to the Company for the purchase of such Shares by other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date, the non-defaulting Underwriters shall be obligated severally, in proportion to their respective commitments hereunder, to purchase the Shares that such defaulting Underwriters agreed but failed to purchase on such Closing Date. If any Underwriter or Underwriters so default and the aggregate number of Shares with respect to which such default or defaults occur exceeds 10% of the total number of Shares that the Underwriters are obligated to purchase on such Closing Date and arrangements satisfactory to the Representatives and the Company for the purchase of such Shares by other persons are not made within 48 hours after such default, this Agreement will terminate without liability on the part of any non-defaulting Underwriter or the Company, except as provided in Section 4(l) and 9(c) (provided that if such default occurs with respect to Option Shares after the Closing Date, this Agreement will not terminate as to the Firm Shares or any Option Shares purchased prior to such termination). As used in this Agreement, the term “Underwriter” includes any person substituted for an Underwriter under this Section. Nothing herein will relieve a defaulting Underwriter from liability for its default.

9. Miscellaneous.

(a) Notices. Notice given pursuant to any of the provisions of this Agreement shall be in writing and, unless otherwise specified, shall be mailed, hand delivered or telecopied (a) if to the Company, at the office of the Company, 10421 Pacific Center Court, Suite 200, San Diego, California 92121, Attention: President or (b) if to the Underwriters, c/o Credit Suisse Securities (USA) LLC, Eleven Madison Avenue, New York, N.Y. 10010-3629, Attention: LCD-IBD; c/o Jefferies LLC, 520 Madison Avenue, New York, New York 10022, Attention: General Counsel and c/o Stifel, Nicolaus & Company, Incorporated, One Montgomery Street, Suite 3700, San Francisco, California 94104, Attention: Legal Department. Any such notice shall be effective only upon receipt. Any notice under Section 6 hereof may be made by telecopy or telephone, but if so made shall be subsequently confirmed in writing.

(b) No Third Party Beneficiaries; Successors. This Agreement has been and is made solely for the benefit of and will inure to and be binding on the several Underwriters, the Company and the controlling persons, directors, officers, employees, counsel and agents referred to in Section 6 hereof, and their respective successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. The term “successors and assigns” as used in this Agreement shall not include a purchaser of Shares from the Underwriters in his, her or its capacity as such a purchaser.

(c) Survival of Representations and Warranties. All representations, warranties and agreements of the Company or its officers contained herein or in certificates or other instruments delivered pursuant hereto shall remain operative and in full force and effect regardless of any investigation made by or on behalf of any Underwriter or any of their controlling persons and shall survive delivery of and payment for the Shares hereunder.

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(d) Absence of Fiduciary Relationship. The Company acknowledges and agrees that:

(i) No Other Relationship. The Underwriters have been retained solely to act as underwriters in connection with the sale of the Shares and that no fiduciary, advisory or agency relationship between the Company, on the one hand, and the Underwriters, on the other, has been created in respect of any of the transactions contemplated by this Agreement or the final prospectus, irrespective of whether the Underwriters or any of its affiliates have advised or are advising the Company on other matters;

(ii) Arms’ Length Negotiations. The price of the Shares set forth in this Agreement, including the public offering price and any related discounts and commissions, was established by Company following discussions and arms-length negotiations with the Underwriters and the Company is capable of evaluating and understanding and understand and accept the terms, risks and conditions of the transactions contemplated by this Agreement;

(iii) Absence of Obligation to Disclose. The Company has been advised that the Underwriters and their affiliates are engaged in a broad range of transactions which may involve interests that differ from those of the Company and that the Underwriters have no obligation to disclose such interests and transactions to the Company by virtue of any fiduciary, advisory or agency relationship;

(iv) Waiver. The Company waives, to the fullest extent permitted by law, any claims they may have against the Underwriters for breach of fiduciary duty or alleged breach of fiduciary duty and agree that the Underwriters shall have no liability (whether direct or indirect) to the Company in respect of such a fiduciary duty claim or to any person asserting a fiduciary duty claim on behalf of or in right of the Company, including stockholders, employees or creditors of the Company; and

(v) Accounting, Regulatory and Tax. The Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated by this Agreement and the Company has consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate.

(e) Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED ENTIRELY WITHIN SUCH STATE. Each party hereto hereby irrevocably submits for purposes of any action arising from this Agreement brought by the other party hereto to the jurisdiction of the courts of New York State located in the Borough of Manhattan and the U.S. District Court for the Southern District of New York.

(f) Counterparts. This Agreement may be signed in two or more counterparts with the same effect as if the signatures thereto and hereto were upon the same instrument.

(g) Survival of Provisions Upon Invalidity of Any Single Provision. In case any provision in this Agreement shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.

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(h) Waiver of Jury Trial. The Company and the Underwriters each hereby irrevocably waive any right they may have to a trial by jury in respect of any claim based upon or arising out of this Agreement or the transactions contemplated hereby.

(i) Titles and Subtitles. The titles of the sections and subsections of this Agreement are for convenience and reference only and are not to be considered in construing this Agreement.

(j) Entire Agreement. This Agreement embodies the entire agreement and understanding between the parties hereto and supersedes all prior agreements and understandings relating to the subject matter hereof. This Agreement may not be amended or otherwise modified or any provision hereof waived except by an instrument in writing signed by the Representatives and the Company.

[Signature page follows]

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Please confirm that the foregoing correctly sets forth the agreement between the Company and the several Underwriters.

Very truly yours,
ANAPTYSBIO, INC.
By:
	Name:
	Title:

Confirmed as of the date first above

mentioned:

CREDIT SUISSE SECURITIES (USA) LLC

JEFFERIES LLC

STIFEL, NICOLAUS & COMPANY, INCORPORATED

Acting on behalf of themselves and as

Representatives of the several

Underwriters named in Schedule I hereof

CREDIT SUISSE SECURITIES (USA) LLC

By:
	Name:
	Title:

JEFFERIES LLC

By:
	Name:
	Title:

STIFEL, NICOLAUS & COMPANY, INCORPORATED

By:
	Name:
	Title:

Schedule I

Underwriter	Number of Firm Shares
Credit Suisse Securities (USA) LLC	[•]
Jefferies LLC	[•]
Stifel, Nicolaus & Company, Incorporated	[•]
[•]	[•]
Total	[•]

S-I-1

Schedule II

ISSUER FREE WRITING PROSPECTUSES:

[None].

S-III-1

Schedule III

1. The public offering price per share of Common Stock shall be $[•].

2. The Company is selling [•] shares of Common Stock.

3. The Company has granted an option to the Underwriters, severally and not jointly, to purchase up to an additional [•] shares of Common Stock.

S-III-1

EXHIBIT A

Form of Lock-up Agreement

            , 2017

Credit Suisse Securities (USA) LLC

Jefferies LLC

Stifel, Nicolaus & Company, Incorporated

As Representatives of the Several Underwriters

c/o Credit Suisse Securities (USA) LLC

Eleven Madison Avenue

New York, N.Y. 10010-3629

c/o Jefferies LLC

520 Madison Avenue

New York, New York 10022

and

c/o Stifel, Nicolaus & Company, Incorporated

One Montgomery Street, Suite 3700

San Francisco, California 94104

Ladies and Gentlemen:

In consideration of the agreement of the several underwriters (the “Underwriters”), for which Credit Suisse Securities (USA) LLC (“Credit Suisse”), Jefferies LLC and Stifel, Nicolaus & Company, Incorporated intend to act as Representatives, to underwrite a proposed public offering (the “Offering”) of shares of common stock, par value $0.001 per share (the “Stock”), of AnaptysBio, Inc., a Delaware corporation (the “Company”), the undersigned hereby irrevocably agrees that the undersigned shall not, for a period (the “Lock-Up Period”) beginning on the date of this Lock-Up Agreement and ending 90 days after the date of the final prospectus for the Offering (the “Prospectus”), without the prior written consent of Credit Suisse (which consent may be withheld in its sole discretion), (1) offer to sell, sell, pledge, contract to sell, purchase any option to sell, grant any option for the purchase of, lend, or otherwise dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition by the undersigned or any controlled affiliate of the undersigned), directly or indirectly, including the filing (or participation in the filing) with the Securities and Exchange Commission of a registration statement under the Securities Act of 1933, as amended (the “Securities Act”), to register, any shares of Stock or any securities convertible into or exercisable or exchangeable for Stock or warrants or other rights to acquire shares of Stock of which the undersigned is now, or may in the future become, the beneficial owner (within the meaning of Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) (such shares, securities, warrants or rights, collectively, the “Restricted Securities”), or (2) enter into any swap or other derivatives transaction that transfers to another, in whole or in part, any of the economic benefits

or risks of ownership of such Restricted Securities, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Stock or other securities, in cash or otherwise, or (3) publicly disclose the intention to enter into any transaction described in clause (1) or (2) above. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of Restricted Securities owned either of record or beneficially by the undersigned except in compliance with the foregoing restrictions. Any securities of the Company acquired by the undersigned in the Offering (including, without limitation, in any issuer-directed share program) will also be Restricted Securities subject to this Lock-Up Agreement.

The foregoing restrictions shall not apply to: (i) transfers of Restricted Securities as a bona fide gift or gifts by the undersigned; (ii) transfers or dispositions of Restricted Securities to any trust for the direct or indirect benefit of the undersigned or any member of the immediate family of the undersigned; (iii) transfers or dispositions of Restricted Securities to any of the undersigned’s affiliates (within the meaning set forth in Rule 405 under the Securities Act, including any wholly-owned subsidiary of the undersigned or to the parent entity of the undersigned), limited partners, general partners, limited liability company members or stockholders; (iv) transfers of Restricted Securities by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the undersigned; (v) transfers or dispositions of shares of Stock or securities convertible into or exercisable for shares of Stock acquired by the undersigned in open market purchases after the completion of the Offering; (vi) entry by the undersigned into any trading plan established pursuant to Rule 10b5-1 under the Exchange Act; (vii) the exercise of options, warrants or other rights to acquire shares of Stock or any security convertible into or exercisable for shares of Stock in accordance with their terms (including the settlement of restricted stock units and including, in each case, by way of net exercise and/or to cover withholding tax obligations in connection with such exercise, but for the avoidance of doubt, excluding all manners of exercise that would involve a sale of any securities, whether to cover the applicable aggregate exercise price, withholding tax obligations or otherwise) pursuant to an employee benefit plan, option, warrant or other right disclosed in the Prospectus, (viii) transfers pursuant to a court order or settlement agreement related to the distribution of assets in connection with the dissolution of a marriage or civil union, (ix) transfers to the Company pursuant to agreements under which the Company has the option to repurchase such shares or a right of first refusal with respect to transfers of such shares upon termination of service of the undersigned, or (x) the transfer of shares of Stock or any security convertible into or exercisable or exchangeable for Stock pursuant to a liquidation, tender offer, merger, consolidation, binding share exchange or other similar transaction involving a change in control that results in all of the Company’s stockholders having the right to exchange their Stock for cash, securities or other property; provided that if such transaction is not consummated, any such securities shall remain subject to the restrictions set forth in this Lock-Up Agreement; provided, however, that (a) in the case of (i), (ii) (iii), (iv) or (viii) above, it shall be a condition to the transfer or disposition that the donee, trustee, heir, distributee or other transferee, as the case may be, agrees to be bound in writing to the restrictions set forth herein during the Lock-Up Period; (b) any transfer or disposition pursuant to (i), (ii), (iii) or (iv) above shall not involve a disposition for value; (c) in the case of a transfer or distribution pursuant to (i), (ii), (iii) or (v) above, no filing by the undersigned or any other party under the Exchange Act or other public announcement shall be required or made voluntarily during the Lock-Up Period in connection with such transfer or

3

distribution (other than a filing on a Form 5 made after the expiration of the Lock-Up Period and, with respect to clause (viii), other than a filing required to be made on a Form 4 by the undersigned reporting a reduction in beneficial ownership of shares of Stock; provided, that the undersigned shall include a statement in such report to the effect that the transfer occurred by operation of law, such as pursuant to a qualified domestic order or in connection with a divorce settlement, as applicable); (d) in the case of (vi) above, such trading plan does not provide for any sales or other dispositions of Restricted Securities during the Lock-Up Period and no public announcement or filing under the Exchange Act or otherwise is made by or on behalf of the undersigned or the Company regarding the establishment of, or sales under, such plan during the Lock-Up Period; and (e) in the case of (vii) above, the shares of Stock delivered upon such exercise are issued in the name of the undersigned and are subject to the restrictions set forth in this Lock-Up Agreement, and no filing under the Exchange Act or other public announcement (whether voluntarily or otherwise) shall be made during the Lock-Up Period unless such filing or announcement clearly states that no Stock was sold by the undersigned and that the Stock received upon such exercise is subject to this Lock-Up Agreement. For purposes of clause (x) above, “change in control” shall mean the transfer (whether by tender offer, merger, consolidation or similar transaction), in one transaction or a series of related transactions, to a person or group of affiliated persons (other than an Underwriter of the Offering), of the Company’s voting securities if, after such transfer, such person or group of affiliated persons would hold more than 50% of the outstanding voting securities of the Company (or the surviving entity). For the purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage, domestic partnership or adoption, not more remote than first cousin.

With respect to the Offering only, the undersigned waives any registration rights relating to registration under the Securities Act of any shares of Stock owned either of record or beneficially by the undersigned, including rights to receive notice of the Offering, including, without limitation, any registration rights owned by the undersigned pursuant to the Fourth Amended and Restated Investor Rights Agreement dated as of July 13, 2015, by and among the Company and the investors listed in Exhibit A thereto, as may be amended from time to time.

This Lock-Up Agreement shall automatically terminate and become null and void (i) at such time as Credit Suisse or the Company advises the other in writing, prior to the execution of the Underwriting Agreement, that it has determined not to proceed with the Offering, (ii) upon the termination of the Underwriting Agreement if prior to the closing of the Offering, or (iii) on October 31, 2017, if the Offering shall not have closed by such date.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. All authority herein conferred or agreed to be conferred and any obligations of the undersigned shall be binding upon the successors, assigns, heirs or personal representatives of the undersigned. The undersigned understands that the Underwriters are entering into the Underwriting Agreement and proceeding with the Offering in reliance upon this Lock-Up Agreement.

[Signature page follows]

4

This Lock-Up Agreement and any claim, controversy or dispute arising under or related to this Lock-Up Agreement shall be governed by and construed in accordance with the laws of the State of New York applicable to agreements made and to be performed entirely within such state.

Very truly yours,

Name of Security Holder (Print exact name)

By:                                                                                                  

      Signature

If not signing in an individual capacity:

Name of Authorized Signatory (Print)

Title of Authorized Signatory (Print)

(indicate capacity of person signing if signing as custodian, trustee, or on behalf of an entity)

A-1

EX-5.1

EXHIBIT 5.1

October 10, 2017

AnaptysBio, Inc.

10421 Pacific Center Court, Suite 200

San Diego, California 92121

Gentlemen/Ladies:

At your request, we have examined the Registration Statement on Form S-1 filed by AnaptysBio, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”) on October 10, 2017 (the “Registration Statement”) in connection with the registration under the Securities Act of 1933, as amended, of an aggregate of 3,450,000 shares of the Company’s Common Stock (the “Stock”).

In connection with our opinion expressed below we have examined originals or copies of the Company’s Restated Certificate of Incorporation (the “Restated Certificate”) and Amended and Restated Bylaws (the “Restated Bylaws”), certain corporate proceedings of the Company’s board of directors (the “Board”) and stockholders relating to the Registration Statement, the Company’s Restated Certificate and Restated Bylaws, and such other agreements, documents, certificates and statements of the Company, its transfer agent and public or government officials, as we have deemed advisable, and have examined such questions of law as we have considered necessary. We have assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures on documents submitted to us, the conformity to originals of all documents submitted to us as copies, and the absence of any undisclosed termination, waiver or amendment to any document reviewed by us. In giving our opinion, we have also relied upon a good standing certificate regarding the Company issued under other outstanding securities or plans of the Company, to enable the Company to issue and deliver all of the Stock as of the date of this letter.

We render this opinion only with respect to, and express no opinion herein concerning the application or effect of the laws of any jurisdiction other than, the existing laws of the Delaware General Corporation Law.

Based upon, and subject to, the foregoing, we are of the opinion that up to 3,450,000 shares of Stock to be issued and sold by the Company, when issued, sold and delivered in the manner and for the consideration stated in the Registration Statement and the Prospectus and in accordance with the resolutions adopted by the Company’s Board and to be adopted by the Pricing Committee of the Board, will be validly issued, fully paid and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement and further consent to all references to us, if any, in the Registration Statement, the Prospectus constituting a part thereof and any amendments thereto. We do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission

October 10, 2017

Page 2

thereunder. This opinion is intended solely for use in connection with issuance and sale of the Stock subject to the Registration Statement and is not to be relied upon for any other purpose. In providing this letter, we are opining only as to the specific legal issues expressly set forth above, and no opinion shall be inferred as to any other matter or matters. This opinion is rendered on, and speaks only as of, the date of this letter first written above, and does not address any potential change in facts of law that may occur after the date of this opinion letter. We assume no obligation to advise you of any fact, circumstance, event or change in the law or the facts that may hereafter be brought to our attention, whether or not such occurrence would affect or modify any of the opinions expressed herein.

Very truly yours,

/s/ Fenwick & West LLP

FENWICK & WEST LLP

EX-10.8

Exhibit 10.8

ANAPTYSBIO, INC.

EMPLOYMENT AGREEMENT

This EMPLOYMENT AGREEMENT (this “Agreement”) is made effective from January 9^th, 2017 (the “Effective Date”) by and among ANAPTYSBIO, INC. (the “Company”) and Dominic Piscitelli (“CFO”). The Company and CFO are hereinafter collectively referred to as the “Parties”, and individually referred to as a “Party”.

RECITAL

The Company desires to employ CFO, and CFO is willing to accept such employment by Company, on the terms and subject to the conditions set forth in this Agreement.

AGREEMENT

In consideration of the foregoing Recitals and the mutual promises and covenants herein contained, and for other good and valuable consideration, the Parties, intending to be legally bound, agree as follows:

1. EMPLOYMENT.

1.1 Title. Effective as of the Effective Date, CFO’s position shall be Chief Financial Officer of the Company, subject to the terms and conditions set forth in this Agreement.

1.2 Term. The term of this Agreement shall begin on the Effective Date and shall continue until it is terminated pursuant to Section 4 herein (the “Term”).

1.3 Duties. CFO shall do and perform all services, acts or things necessary or advisable to manage and conduct the business of the Company and that are normally associated with the position of Chief Financial Officer. CFO shall report to the Chief Executive Officer.

1.4 Policies and Practices. The employment relationship between the Parties shall be governed by this Agreement and by the policies and practices established by the Company and/or the Board, or any designated committee thereof. In the event that the terms of this Agreement differ from or are in conflict with the Company’s policies or practices or the Company’s Employee Handbook, this Agreement shall control.

1.5 Location. Unless the Parties otherwise agree in writing, during the Term CFO shall perform the services CFO is required to perform pursuant to this Agreement at the Company’s offices in San Diego, California, provided, however, that the Company may from time to time require CFO to travel temporarily to other locations in connection with the Company’s business.

2. LOYALTY; NONCOMPETITION; NONSOLICITATION.

2.1 Loyalty. During CFO’s employment with the Company, CFO shall devote CFO’s full business energies, interest, abilities and productive time to the proper and efficient performance of CFO’s duties under this Agreement.

2.2 Agreement not to Participate in Company’s Competitors. During CFO’s employment with the Company, CFO agrees not to acquire, assume or participate in, directly or indirectly, any position, investment or interest known by CFO to be adverse or antagonistic to the Company, its business, or prospects, financial or otherwise, or in any company, person, or entity that is, directly or indirectly, in competition with the business of the Company or any of its Affiliates (as defined below). Ownership by CFO, in professionally managed funds over which CFO does not have control or discretion in investment decisions, or as a passive investment, of less than two percent (2%) of the outstanding shares of capital stock of any corporation with one or more classes of its capital stock listed on a national securities exchange or publicly traded on a national securities exchange or in the over-the-counter market shall not constitute a breach of this Section. For purposes of this Agreement, “Affiliate,” means, with respect to any specific entity, any other entity that, directly or indirectly, through one or more intermediaries, controls, is controlled by or is under common control with such specified entity.

2.3 Covenant not to Compete. During CFO’s employment with the Company, CFO shall not engage in competition with the Company and/or any of its Affiliates in any manner or capacity, as adviser, principal, agent, affiliate, promoter, partner, officer, director, employee, owner, co-owner, consultant, in any phase of the business of developing, manufacturing and marketing of products or services that directly compete with the products or services of the Company, except with the prior written consent of the CEO. CFO shall be entitled to request written consent of the CEO with respect to potential advisory and/or director opportunities presented to CFO by a third party, which CFO believes in good faith will not interfere or compete with the on-going business of the Company.

3. COMPENSATION OF CFO.

3.1 Base Salary. The Company shall pay CFO a base salary at the annualized rate of $365,000 (the “Base Salary”), less payroll deductions and all required withholdings, payable in regular periodic installments in accordance with the Company’s normal payroll practices. The Base Salary shall be prorated for any partial year of employment on the basis of a 365-day fiscal year.

3.2 Discretionary Bonus. At the sole discretion of the Board and Chief Executive Officer, promptly following each calendar year of employment CFO shall be eligible to receive a discretionary cash bonus of up to 30% of CFO’s then-current base salary (the “Bonus”), based on CFO’s achievement relative to certain performance goals (“Performance Goals”) to be established by the Chief Executive Officer in writing in a manner reasonably consistent with the Company’s priorities. The determination of whether CFO has met the Performance Goals for any given year, and if so, the amount of any Bonus that will be paid for such year (if any), shall be determined by the Board and Chief Executive Officer in their sole and

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absolute discretion. In order to be eligible to earn or receive any Bonus, CFO must remain employed by the Company through and including the date of payment of such Bonus. For the first calendar year of CFO’s employment with Company, the Bonus payable shall be pro-rated in accordance with the percentage of the calendar year that the CFO is an employee of the Company.

3.3 Sign-On Bonus. Conditional upon the CFO initiating employment with the Company as of the Effective Date, Company agrees to pay CFO an aggregate sign-on bonus of $100,000, of which one-half ($50,000) is payable to CFO within thirty (30) days of the Effective Date, and the second half ($50,000) will be payable thirty (30) days subsequent to the earlier of (i) closing of an initial public offering of the Company’s stock and (ii) the six (6) month anniversary of the Effective Date.

3.4 Relocation. CFO in good faith intends to relocate his household to the San Diego area as soon as practical, but no later than four (4) months following the Effective Date. Until such time as CFO relocates, CFO agrees to spend at least 4 days per week at the Company’s offices in San Diego, unless as otherwise approved on a week-to-week basis by the Chief Executive Officer. The Company will cover the actual and reasonable costs, including out-of-pocket relocation, commuting and related tax expense, associated with CFO’s relocation to the San Diego area, up to a maximum of $40,000, exclusive of any tax gross-up payment. CFO must remain employed by the Company through and including the date of payment of any such amounts payable under this Section 3.4, and all such payments will be subject to any necessary payroll deductions and all required withholdings.

3.5 Stock Option. As soon as practicable following the Effective Date, CFO will be granted an option to purchase up to 1,191,695 shares of the Company’s Common Stock (the “Base Option”) pursuant to the terms of the Company’s 2006 Equity Incentive Plan, as amended from time to time (the “Plan”). The Base Option shall be subject to vesting such that, subject to CFO’s continued employment with the Company, 1/4 of the shares subject to the Base Option shall vest as of the first anniversary of the Effective Date and l/48^th of the shares subject to the Base Option shall vest in equal monthly installments on the monthly anniversary of the Effective Date of each month for the 36 months thereafter. The exercise price per share of the Base Option will be equal to the fair market value of a single share of Common Stock on the date the Base Option is granted, as determined in good faith by the Board. The Base Option will be governed by the Plan and shall be granted pursuant to a separate stock option grant notice and stock option agreement.

3.6 Expense Reimbursements. The Company will reimburse CFO for all reasonable business expenses CFO incurs in conducting his duties hereunder, pursuant to the Company’s usual expense reimbursement policies; provided that CFO supplies the appropriate substantiation for such expenses no later than the end of the calendar month following the month in which such expenses were incurred by CFO.

3.7 Changes to Compensation. CFO’s compensation will be reviewed annually and may be changed from time to time in the Company’s sole discretion.

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3.8 Employment Taxes. All of CFO’s compensation shall be subject to customary withholding taxes and any other employment taxes as are commonly required to be collected or withheld by the Company.

3.9 Benefits. CFO shall, in accordance with Company policy and the terms of the applicable plan documents, be eligible to participate in benefits under any benefit plan or arrangement that may be in effect from time to time and made available to the Company’s senior management employees.

3.10 Holidays and Vacation. CFO shall be eligible for paid holiday and vacation time in accordance with Company policy as in effect from time to time.

4. TERMINATION.

4.1 Termination by the Company. CFO’s employment with the Company is at will and may be terminated by the Company at any time and for any reason, or for no reason, including, but not limited to, under the following conditions:

4.1.1 Termination by the Company for Cause. The Company may terminate CFO’s employment under this Agreement for “Cause” (as defined below) by delivery of written notice to CFO. Any notice of termination given pursuant to this section shall effect termination as of the date of the notice, or as of such other date specified in the notice.

4.1.2 Termination by the Company without Cause. The Company may terminate CFO’s employment under this Agreement without Cause at any time and for any reason, or for no reason. Such termination shall be effective on the date CFO is so informed, or as otherwise specified by the Company.

4.2 Termination by CFO. CFO may terminate his employment with the Company at any time and for any reason, or for no reason, upon thirty (30) days written notice to the Company.

4.3 Termination for Death or Disability. CFO’s employment with the Company shall automatically terminate effective upon the date of CFO’s death or Disability (as defined in the Plan).

4.4 Termination by Mutual Agreement of the Parties. CFO’s employment with the Company may be terminated at any time upon a mutual agreement in writing of the Parties. Any such termination of employment shall have the consequences specified in such agreement.

4.5 Compensation upon Termination.

4.5.1 Death or Disability. If CFO’s employment is terminated by death or Disability, the Company shall pay to CFO, or to CFO’s heirs, CFO’s accrued and unpaid base salary and accrued and unused vacation benefits earned through the date of termination at the rate in effect at the time of termination, less standard deductions and withholdings. The

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Company shall thereafter have no further obligations to CFO and/or CFO’s heirs under this Agreement, except as otherwise provided by law.

4.5.2 Termination For Cause. If the Company terminates CFO’s employment for Cause, then the Company shall pay CFO’s accrued and unpaid base salary and accrued and unused vacation benefits earned through the date of termination, at the rate in effect at the time of termination, less standard deductions and withholdings. The Company shall thereafter have no further obligations to CFO under this Agreement, except as otherwise provided by law.

4.5.3 Termination by Company Without Cause or by CFO for Good Reason Not In Connection with a Change in Control. If the Company terminates CFO’s employment without Cause or if CFO resigns his employment for Good Reason, in either case at any time other than upon the occurrence of, or within the 13 months immediately following, the effective date of a “Change in Control” (as defined in the Plan), the Company shall pay CFO’s accrued and unpaid base salary and accrued and unused vacation benefits earned through the date of termination, at the rate in effect at the time of termination, less standard deductions and withholdings. In addition to the above, if CFO furnishes to the Company an executed waiver and release of claims in the form attached hereto as Exhibit A (or in such other form as may be specified by the Company) (the “Release”) within the time period specified therein, but in no event later than 45 days following CFO’s termination, and if CFO allows such Release to become effective in accordance with its terms, then (i) CFO shall be entitled to severance in the form of continuation of his base salary, at the base salary rate equal to the greater of the rate in effect at the time of termination or immediately prior to the event giving rise to the Good Reason (the “Severance Payments”), for a period of nine (9) months following the termination date (the “Severance Period”), and (ii) the Company will pay directly to the insurance provider the premium for COBRA continuation coverage for CFO and CFO’s family during the Severance Period or until he obtains new employment, whichever comes first (the “COBRA Coverage”); provided, however, that notwithstanding anything herein, if the Company determines in its sole discretion that it cannot provide the foregoing COBRA Coverage benefit without potentially violating, or being subject to an excise tax under, applicable law (including, without limitation, Section 2716 of the Public Health Service Act), the Company will in lieu thereof provide to CFO a taxable monthly payment, payable on the last day of a given month, in an amount equal to the monthly COBRA Coverage that CFO would be required to pay to continue CFO’s group health coverage in effect on the termination of employment date (which amount will be based on the premium for the first month of COBRA coverage). The Severance Payments will be subject to standard payroll deductions and withholdings and will be made on the Company’s regular payroll cycle, provided, however, that any Severance Payments otherwise scheduled to be made prior to the effective date of the Release shall accrue and be paid in the first payroll period that follows such effective date. The Company shall thereafter have no further obligations to CFO under this Agreement, except as otherwise provided by law.

4.5.4 Termination by Company Without Cause or by CFO for Good Reason In Connection with a Change in Control. If the Company terminates CFO’s employment without Cause or if CFO resigns his employment for Good Reason, in either case upon the occurrence of, or within the 13 months immediately following, the effective date of a Change in Control, the Company shall pay CFO’s accrued and unpaid base salary and accrued

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and unused vacation benefits earned through the date of termination, at the rate in effect at the time of termination, less standard deductions and withholdings. In addition, if CFO furnishes to the Company an executed Release within the time period specified therein, but in no event later than 45 days following CFO’s termination, and if CFO allows such Release to become effective in accordance with its terms, then CFO shall be entitled to: (1) the Severance Payments and COBRA coverage described in Section 4.5.3 above and (2) accelerated vesting of any unvested shares subject to the Base Option, such that CFO shall become vested in 100% of the shares subject to such Base Option on the effective date of the Release. The Company shall thereafter have no further obligations to CFO under this Agreement, except as otherwise provided by law.

4.6 Definitions. For purposes of this Agreement, the following terms shall have the following meanings:

4.6.1 “Cause” shall mean the occurrence of any one or more of the following: (i) CFO’s commission of any crime involving fraud, dishonesty or moral turpitude; (ii) CFO’s attempted commission of or participation in a fraud or act of dishonesty against the Company that results in (or might have reasonably resulted in) material harm to the business of the Company; (iii) CFO’s intentional, material violation of any contract or agreement between CFO and the Company or any statutory duty CFO owes to the Company; or (iv) CFO’s conduct that constitutes gross insubordination, incompetence or habitual neglect of duties and that results in (or might have reasonably resulted in) material harm to the business of the Company; provided, however, that the action or conduct described in clauses (iii) and (iv) above will constitute “Cause” only if such action or conduct continues after the Company has provided CFO with written notice thereof and thirty (30) days to cure, or otherwise remedy to the extent possible under direct control of the CFO, the same. An occurrence of “Cause” as set forth in the preceding sentence shall be based upon a good faith determination by the Board. CFO’s Disability shall not constitute Cause as set forth herein. The determination that a termination is for Cause shall be by the Board in its sole and exclusive judgment and discretion.

4.6.2 “Good Reason” shall mean any of the following actions: (i) the assignment to CFO of any duties or responsibilities that results in a material diminution in CFO’s function (for Section 4.5.4, as in effect immediately prior to the effective date of the Change in Control); provided, however, that a change in CFO’s title or reporting relationships shall not provide the basis for a voluntary termination with Good Reason; (ii) a reduction by the Company in CFO’s annual base salary as in effect immediately prior to the effective date of the Change in Control; provided, however, that Good Reason shall not be deemed to have occurred in the event of a reduction in CFO’s annual base salary that is pursuant to a salary reduction program affecting substantially all of the employees of the Company and that does not adversely affect CFO to a greater extent than other similarly situated employees; or (iii) a relocation of CFO’s primary business office to a location more than 50 miles from the location of CFO’s primary business office and which increases the CFO’s commute (for Section 4.5.4, as in effect immediately prior to the effective date of the Change in Control), except for required travel by CFO on the Company’s business to an extent substantially consistent with CFO’s business travel obligations prior to the effective date of the Change in Control; provided, that CFO may not resign for Good Reason without first providing the Company with written notice within ninety (90) days of the date of the initial existence of the condition that CFO believes constitutes Good Reason specifically identifying the acts or omissions constituting the grounds for Good Reason

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and a reasonable cure period of not less than thirty (30) days and not more than ninety (90) days following the date of such notice.

4.7 Survival of Certain Sections. Sections 3.4, 3.6 and 4 through 18 of this Agreement will survive the termination of this Agreement.

4.8 Parachute Payment. If any payment or benefit CFO would receive pursuant to this Agreement (“Payment”) would (i) constitute a “Parachute Payment” within the meaning of Section 280G of the Internal Revenue Code of 1986, as amended (the “Code”), and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then such Payment shall be equal to the Reduced Amount. The “Reduced Amount” shall be either (x) the largest portion of the Payment that would result in no portion of the Payment being subject to the Excise Tax or (y) the largest portion, up to and including the total of the Payment, whichever amount, after taking into account all applicable federal, state and local employment taxes, income taxes, and the Excise Tax (all computed at the highest applicable marginal rate), results in CFO’s receipt, on an after-tax basis, of the greatest economic benefit notwithstanding that all or some portion of the Payment may be subject to the Excise Tax. If a reduction in payments or benefits constituting Parachute Payments is necessary so that the Payment equals the Reduced Amount, reduction shall occur in the manner that results in the greatest economic benefit for CFO. If more than one method of reduction will result in the same economic benefit, the items so reduced will be reduced pro rata.

In the event it is subsequently determined by the Internal Revenue Service that some portion of the Reduced Amount (as determined pursuant to clause (x) in the preceding paragraph) is subject to the Excise Tax, CFO agrees to promptly return to the Company a sufficient amount of the Payment so that no portion of the Reduced Amount is subject to the Excise Tax. For the avoidance of doubt, if the Reduced Amount is determined in accordance with clause (y) in the preceding paragraph, CFO will have no obligation to return any portion of the Payment pursuant to the preceding sentence.

Unless CFO and the Company agree on an alternative accounting or law firm, the accounting firm then engaged by the Company for general tax compliance purposes shall perform the foregoing calculations. If the accounting firm so engaged by the Company is serving as accountant or auditor for the individual, entity or group effecting the Change in Control, the Company shall appoint a nationally recognized accounting, law or consulting firm to make the determinations required hereunder. The Company shall bear all expenses with respect to the determinations by such accounting, law or consulting firm required to be made hereunder.

The Company shall use commercially reasonable efforts such that the accounting, law or consulting firm engaged to make the determinations hereunder shall provide its calculations, together with detailed supporting documentation, to CFO and the Company within 15 calendar days after the date on which CFO’s right to a Payment is triggered (if requested at that time by CFO or the Company) or such other time as requested by CFO or the Company.

4.9 Application of Internal Revenue Code Section 409A. Notwithstanding anything to the contrary set forth herein, any payments and benefits provided under this Agreement (the “Severance Benefits”) that constitute “deferred compensation” within the

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meaning of Section 409A of the Code and the regulations and other guidance thereunder and any state law of similar effect (collectively “Section 409A”) shall not commence in connection with CFO’s termination of employment unless and until CFO has also incurred a “separation from service” (as such term is defined in Treasury Regulation Section 1.409A-1(h) (“Separation From Service”), unless the Company reasonably determines that such amounts may be provided to CFO without causing CFO to incur the additional 20% tax under Section 409A.

It is intended that each installment of the Severance Benefits payments provided for in this Agreement is a separate “payment” for purposes of Treasury Regulation Section 1.409A-2(b)(2)(i). For the avoidance of doubt, it is intended that payments of the Severance Benefits set forth in this Agreement satisfy, to the greatest extent possible, the exemptions from the application of Section 409A provided under Treasury Regulation Sections 1.409A-1(b)(4), 1.409A-1(b)(5) and 1.409A-1(b)(9). However, if the Company (or, if applicable, the successor entity thereto) determines that the Severance Benefits constitute “deferred compensation” under Section 409A and CFO is, on the termination of service, a “specified employee” of the Company or any successor entity thereto, as such term is defined in Section 409A(a)(2)(B)(i) of the Code, then, solely to the extent necessary to avoid the incurrence of the adverse personal tax consequences under Section 409A, the timing of the Severance Benefit payments shall be delayed until the earlier to occur of: (i) the date that is six months and one day after CFO’s Separation From Service, or (ii) the date of CFO’s death (such applicable date, the “Specified Employee Initial Payment Date”), the Company (or the successor entity thereto, as applicable) shall (A) pay to CFO a lump sum amount equal to the sum of the Severance Benefit payments that CFO would otherwise have received through the Specified Employee Initial Payment Date if the commencement of the payment of the Severance Benefits had not been so delayed pursuant to this Section and (B) commence paying the balance of the Severance Benefits in accordance with the applicable payment schedules set forth in this Agreement.

Notwithstanding anything to the contrary set forth herein, CFO shall receive the Severance Benefits described above, if and only if CFO duly executes and returns to the Company within the applicable time period set forth therein, but in no event more than forty-five days following Separation From Service, the Release and permits the Release to become effective in accordance with its terms. Notwithstanding any other payment schedule set forth in this Agreement, none of the Severance Benefits will be paid or otherwise delivered prior to the effective date of the Release. Except to the extent that payments may be delayed until the Specified Employee Initial Payment Date pursuant to the preceding paragraph, on the first regular payroll pay day following the effective date of the Release, the Company will pay CFO the Severance Benefits CFO would otherwise have received under the Agreement on or prior to such date but for the delay in payment related to the effectiveness of the Release, with the balance of the Severance Benefits being paid as originally scheduled. All amounts payable under the Agreement will be subject to standard payroll taxes and deductions.

5. CONFIDENTIAL AND PROPRIETARY INFORMATION.

CFO has already executed, as a condition of CFO’s employment with the Company, the Company’s standard form of Proprietary Information and Inventions Agreement (the “PIIA”). The PIIA remains in full force and effect.

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6. ASSIGNMENT AND BINDING EFFECT.

This Agreement shall be binding upon and inure to the benefit of CFO and CFO’s heirs, executors, personal representatives, assigns, administrators and legal representatives. Because of the unique and personal nature of CFO’s duties under this Agreement, neither this Agreement nor any rights or obligations under this Agreement shall be assignable by CFO. This Agreement shall be binding upon and inure to the benefit of the Company and its successors, assigns and legal representatives. Any such successor of the Company will be deemed substituted for the Company under the terms of this Agreement for all purposes. For this purpose, “successor” means any person, firm, corporation or other business entity which at any time, whether by purchase, merger or otherwise, directly or indirectly acquires all or substantially all of the assets or business of the Company.

7. NOTICES.

All notices or demands of any kind required or permitted to be given by the Company or CFO under this Agreement shall be given in writing and shall be personally delivered (and receipted for) or faxed during normal business hours or mailed by certified mail, return receipt requested, postage prepaid, addressed as follows:

If to the Company:

10421 Pacific Center Court, Suite 200

San Diego, CA 92121

Attention: Chief Executive Officer

If to CFO:

Dominic Piscitelli

Any such written notice shall be deemed given on the earlier of the date on which such notice is personally delivered or three days after its deposit in the United States mail as specified above. Either Party may change its address for notices by giving notice to the other Party in the manner specified in this Section.

8. CHOICE OF LAW.

This Agreement shall be construed and interpreted in accordance with the internal laws of the State of California without regard to its conflict of laws principles.

9. INTEGRATION.

This Agreement, including Exhibit A and the PIIA, contains the complete, final and exclusive agreement of the Parties relating to the terms and conditions of CFO’s employment and the termination of CFO’s employment, and supersedes any and all prior and/or contemporaneous oral and written employment agreements or arrangements between the Parties.

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10. AMENDMENT.

This Agreement cannot be amended or modified except by a written agreement signed by CFO and the Company.

11. WAIVER.

No term, covenant or condition of this Agreement or any breach thereof shall be deemed waived, except with the written consent of the Party against whom the wavier is claimed, and any waiver or any such term, covenant, condition or breach shall not be deemed to be a waiver of any preceding or succeeding breach of the same or any other term, covenant, condition or breach.

12. SEVERABILITY.

The finding by a court of competent jurisdiction of the unenforceability, invalidity or illegality of any provision of this Agreement shall not render any other provision of this Agreement unenforceable, invalid or illegal. Such court shall have the authority to modify or replace the invalid or unenforceable term or provision with a valid and enforceable term or provision, which most accurately represents the Parties’ intention with respect to the invalid or unenforceable term, or provision.

13. INTERPRETATION; CONSTRUCTION.

The headings set forth in this Agreement are for convenience of reference only and shall not be used in interpreting this Agreement. This Agreement has been drafted by legal counsel representing the Company, but CFO has been encouraged to consult with, and has consulted with, CFO’s own independent counsel and tax advisors with respect to the terms of this Agreement. The Parties acknowledge that each Party and its counsel has reviewed and revised, or had an opportunity to review and revise, this Agreement, and any rule of construction to the effect that any ambiguities are to be resolved against the drafting party shall not be employed in the interpretation of this Agreement.

14. REPRESENTATIONS AND WARRANTIES.

CFO represents and warrants that CFO is not restricted or prohibited, contractually or otherwise, from entering into and performing each of the terms and covenants contained in this Agreement, and that CFO’s execution and performance of this Agreement will not violate or breach any other agreements between CFO and any other person or entity.

15. COUNTERPARTS.

This Agreement may be executed in two counterparts, each of which shall be deemed an original, all of which together shall contribute one and the same instrument.

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16. ARBITRATION.

To ensure the rapid and economical resolution of disputes that may arise in connection with CFO’s employment with the Company, CFO and the Company agree that any and all disputes, claims, or causes of action, in law or equity, arising from or relating to CFO’s employment, or the termination of that employment, will be resolved, to the fullest extent permitted by law, by final, binding and confidential arbitration pursuant to both the substantive and procedural provisions of the Federal Arbitration Act in San Diego, California conducted by the Judicial Arbitration and Mediation Services/Endispute, Inc. (“JAMS”), or its successors, under the then current rules of JAMS for employment disputes; provided that the arbitrator shall: (a) have the authority to compel adequate discovery for the resolution of the dispute and to award such relief as would otherwise be permitted by law; and (b) issue a written arbitration decision including the arbitrator’s essential findings and conclusions and a statement of the award. Accordingly, CFO and the Company hereby waive any right to a jury trial. Both CFO and the Company shall be entitled to all rights and remedies that either CFO or the Company would be entitled to pursue in a court of law. The Company shall pay any JAMS filing fee and shall pay the arbitrator’s fee. Nothing in this Agreement is intended to prevent either CFO or the Company from obtaining injunctive relief in court to prevent irreparable harm pending the conclusion of any such arbitration. Notwithstanding the foregoing, CFO and the Company each have the right to resolve any issue or dispute involving confidential, proprietary or trade secret information, or intellectual property rights, by Court action instead of arbitration.

17. TRADE SECRETS OF OTHERS.

It is the understanding of both the Company and CFO that CFO shall not divulge to the Company and/or its subsidiaries any confidential information or trade secrets belonging to others, including CFO’s former employers, nor shall the Company and/or its Affiliates seek to elicit from CFO any such information. Consistent with the foregoing, CFO shall not provide to the Company and/or its Affiliates, and the Company and/or its Affiliates shall not request, any documents or copies of documents containing such information.

18. ADVERTISING WAIVER.

CFO agrees to permit the Company, and persons or other organizations authorized by the Company, to use, publish and distribute advertising or sales promotional literature concerning the products and/or services of the Company, or the machinery and equipment used in the provision thereof, in which CFO’s name and/or pictures of CFO taken in the course of CFO’s provision of services to the Company appear. CFO hereby waives and releases any claim or right CFO may otherwise have arising out of such use, publication or distribution.

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IN WITNESS WHEREOF, the Parties have executed this Agreement as of the dates below.

ANAPTYSBIO, INC.
By:	/s/ Hamza Suria
Its:	President & CFO
Dated:	January 8, 2017
CFO:
/s/ Dominic Piscitelli
DOMINIC PISCITELLI
Dated: 1/8/17

[SIGNATURE PAGE TO EMPLOYMENT AGREEMENT]

EXHIBIT A

RELEASE AND WAIVER OF CLAIMS

TO BE SIGNED ON OR FOLLOWING THE SEPARATION DATE ONLY

In consideration of the payments and other benefits set forth in the Employment Agreement effective                         , 201    , to which this form is attached, I, Dominic Piscitelli, hereby furnish ANAPTYSBIO, INC. (the “Company”), with the following release and waiver (“Release and Waiver”).

In exchange for the consideration provided to me by the Employment Agreement that I am not otherwise entitled to receive, I hereby generally and completely release the Company and its current and former directors, officers, employees, stockholders, partners, agents, attorneys, predecessors, successors, parent and subsidiary entities, insurers, affiliates, and assigns (collectively, the “Released Parties”) from any and all claims, liabilities and obligations, both known and unknown, that arise out of or are in any way related to events, acts, conduct, or omissions occurring prior to or on the date that I sign this Agreement (collectively, the “Released Claims”). The Released Claims include, but are not limited to: (a) all claims arising out of or in any way related to my employment with the Company, or the termination of that employment; (b) all claims related to my compensation or benefits from the Company including salary, bonuses, commissions, vacation pay, expense reimbursements, severance pay, fringe benefits, stock, stock options, or any other ownership interests in the Company; (c) all claims for breach of contract, wrongful termination, and breach of the implied covenant of good faith and fair dealing; (d) all tort claims, including claims for fraud, defamation, emotional distress, and discharge in violation of public policy; and (e) all federal, state, and local statutory claims, including claims for discrimination, harassment, retaliation, misclassification, attorneys’ fees, or other claims arising under the federal Civil Rights Act of 1964 (as amended), the federal Americans with Disabilities Act of 1990, the federal Age Discrimination in Employment Act of 1967 (as amended) (the “ADEA”), the California Labor Code, and the California Fair Employment and Housing Act (as amended). Notwithstanding the foregoing, the following are not included in the Released Claims (the “Excluded Claims”): (a) any rights or claims for indemnification I may have pursuant to the charter or bylaws of the Company or under applicable law; (b) any rights or claims to unemployment compensation, funds accrued in my 401k account, or any vested equity incentives; (c) any rights that are not waivable as a matter of law; or (d) any claims arising from the breach of this Agreement. I hereby represent and warrant that, other than the Excluded Claims, I am not aware of any claims I have or might have against any of the Released Parties that are not included in the Released Claims.

I also acknowledge that I have read and understand Section 1542 of the California Civil Code which reads as follows: “A general release does not extend to claims which the creditor does not know or suspect to exist in his or her favor at the time of executing the release, which if known by him or her must have materially affected his or her settlement with the debtor.” I hereby expressly waive and relinquish all rights and benefits under that Section and any law of any jurisdiction, including New York, of similar effect with respect to any claims I may have against the Company.

I acknowledge that, among other rights, I am waiving and releasing any rights I may have under ADEA, that this Release and Waiver is knowing and voluntary, and that the consideration given for this Release and Waiver is in addition to anything of value to which I was already entitled as an executive of the Company. I further acknowledge that I have been advised, as required by the Older Workers Benefit Protection Act, that: (a) the release and waiver granted herein does not relate to claims under the ADEA which may arise after this Release and Waiver is executed; (b) I should consult with an attorney prior to executing this Release and Waiver; and (c) if I am age 40 or older at the time of execution of this release, I have 21 days from the date of termination of my employment with the Company in which to consider this Release and Waiver (although I may choose voluntarily to execute this Release and Waiver earlier); and (d) if I am age 40 or older at the time of execution of this release, I have seven days following the execution of this Release and Waiver to revoke my consent to this Release and Waiver and this Release and Waiver shall not be effective until the seven day revocation period has expired without my having previously revoked this Release and Waiver.

I agree not to disparage the Company and its officers, directors, employees, shareholders and/or agents, in any manner likely to be harmful to them or their business, business reputations or personal reputations; provided that I may respond accurately and fully to any question, inquiry or request for information when required by legal process (e.g., a valid subpoena or other similar compulsion of law) or as part of a government investigation.

I acknowledge my continuing obligations under my Proprietary Information and Inventions Agreement. Pursuant to the Proprietary Information and Inventions Agreement I understand that among other things, I must not use or disclose any confidential or proprietary information of the Company and I must immediately return all Company property and documents (including all embodiments of proprietary information) and all copies thereof in my possession or control. I understand and agree that my right to the severance pay I am receiving in exchange for my agreement to the terms of this Release and Waiver is contingent upon my continued compliance with my Proprietary Information and Inventions Agreement.

This Release and Waiver constitutes the complete, final and exclusive embodiment of the entire agreement between the Company and me with regard to the subject matter hereof. I am not relying on any promise or representation by the Company that is not expressly stated herein. This Release and Waiver may only be modified by a writing signed by both me and a duly authorized officer of the Company.

Date:                                                                             By:                                                                          

Dominic Piscitelli

2

EX-23.1

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

The Board of Directors

AnaptysBio, Inc.:

We consent to the use of our report incorporated by reference and to the reference to our firm under the heading “Experts” in the prospectus.

/s/ KPMG LLP

San Diego, California

October 10, 2017