anab-20221231

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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FORM 10-K

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For the fiscal year ended December 31, 2022

FOR THE TRANSITION PERIOD FROM TO

Commission File Number: 001-37985

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ANAPTYSBIO, INC.

(Exact name of registrant as specified in its charter)

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10770 Wateridge Circle, Suite 210

San Diego, CA92121

(Address of principal executive offices and zip code)

(858) 362-6295

(Registrant’s telephone number, including area code)

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

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock, $0.001 par value ANAB The Nasdaq Stock Market LLC

Securities registered pursuant to Section 12(g) of the Act: None

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

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

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

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒ No ☐

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 ☒ 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 pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

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

The aggregate market value of voting common equity held by non-affiliates of the registrant was $400,388,471 as of June 30, 2022.

The number of shares of Registrant’s Common Stock outstanding was 27,931,028 as of February 27, 2023.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Definitive Proxy Statement relating to the 2023 Annual Meeting of Stockholders, scheduled to be held on June 15, 2023, are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein. The Definitive Proxy Statement will be filed within 120 days of the Registrant’s fiscal year ended December 31, 2022. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.

TABLE OF CONTENTS

Page

PART I

Item 1. Business 2

Item 1A. Risk Factors 21

Item 1B. Unresolved Staff Comments 52

Item 2. Properties 52

Item 3. Legal Proceedings 52

Item 4. Mine Safety Disclosures 52

PART II

Item 6. Reserved 53

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 65

Item 8. Consolidated Financial Statements and Supplementary Data 67

Item 9A. Controls and Procedures 94

Item 9B. Other Information 94

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 95

PART III

Item 10. Directors, Executive Officers and Corporate Governance 95

Item 11. Executive Compensation 95

Item 14. Principal Accounting Fees and Services 95

PART IV

Item 15. Exhibits, Consolidated Financial Statement Schedules 96

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K (“Annual Report”) contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and section 27A of the Securities Act of 1933, as amended (the “Securities Act”). The words “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” and “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 report 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 two checkpoint agonists in clinical-stage development: rosnilimab and ANB032;

•the impact of political, economic or public health events, such as the coronavirus (“COVID-19”) pandemic on our business and the United States (“U.S.”) and global economies;

•the likelihood that the clinical data generated in any study we performed, are performing, or plan to perform in a non-U.S. jurisdiction will be subsequently accepted by the U.S. Food and Drug Administration (“FDA”) and/or by 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 find a licensing partner for imsidolimab and etokimab;

•our ability to obtain funding for our operations on favorable terms or at all, including funding necessary to complete further development and commercialization of our product candidates;

•general macro-economic factors, including volatility in equity markets, and fluctuations in interest rates and foreign exchange rates;

•the timing of and the ability to obtain and maintain regulatory approvals for our product candidates, partnered product candidates and/or product candidates for which we may receive royalties;

•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 U.S. and 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 our public offerings and other financing transactions;

•our ability to generate potentially best-in-class antibodies through our antibody research platform that are consistent with our commercial objectives; and

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

These forward-looking statements are subject to a number of risks, uncertainties, and assumptions, including those described in Item 1A, “Risk Factors,” and elsewhere in this Annual Report. 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 Annual Report 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 to conform these statements to actual results or to changes in our expectations, except as required by law.

You should read this Annual Report with the understanding that our actual future results, levels of activity, performance, and events and circumstances may be materially different from what we expect.

Unless the context indicates otherwise, as used in this Annual Report, the terms “AnaptysBio,” “company,” “we,” “us” and “our” refer to AnaptysBio, Inc., a Delaware corporation, and its subsidiaries taken as a whole, unless otherwise noted. AnaptysBio is our common law trademark. This Annual Report contains additional trade names, trademarks, and service marks of other companies, which are the property of their respective owners. We do not intend our use or display of other companies’ trade names, trademarks, or service marks to imply a relationship with, or endorsement or sponsorship of us by, these other companies.

PART I

Item 1. Business

Overview

We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics. We are developing immune cell modulating antibodies, including two wholly owned checkpoint agonists in clinical-stage development, for autoimmune and inflammatory disease: rosnilimab, our PD-1 agonist, previously referred to as ANB030, in a planned Phase 2b trial for the treatment of moderate-to-severe rheumatoid arthritis (“RA”); and ANB032, our BTLA agonist, in a planned Phase 2b trial for the treatment of moderate-to-severe atopic dermatitis (“AD”). We also have other preclinical immune cell modulator candidates in our portfolio, including ANB033, an anti-CD122 antagonist antibody for the treatment of autoimmune and inflammatory diseases. In addition, we have two cytokine antagonists that we are exploring options for out-licensing: imsidolimab, our anti-IL-36R antibody, in a Phase 3 trial for the treatment of generalized pustular psoriasis (“GPP”), and etokimab, our anti-IL-33 antagonist that is Phase 2/3 ready. We have also discovered multiple therapeutic antibodies licensed to GlaxoSmithKline, Inc. (“GSK”) in a financial collaboration for immune-oncology, including an anti-PD-1 antagonist antibody (JEMPERLI (dostarlimab-gxly)), an anti-TIM-3 antagonist antibody (cobolimab, GSK4069889) and an anti-LAG-3 antagonist antibody (GSK4074386). We currently recognize revenue from milestones and royalties achieved under our immuno-oncology collaboration with GSK.

Our Wholly Owned Product Candidate Pipeline

Our immune cell modulating antibodies, including anti-inflammatory checkpoint agonists for PD-1 and BTLA, treat inflammatory disorders by down regulating immune responses mediated by multiple immune cell types including T-cells, B-cells, and dendritic cells. We believe these molecules have potential applicability across a broad range of autoimmune and inflammatory disorders including dermatology, rheumatology, gastroenterology, respiratory, and neurology therapeutic areas.

Rosnilimab

Rosnilimab is designed to suppress aberrant T cell driven inflammation by augmenting signaling through PD-1 or targeted depletion of PD-1+ T cells.

Rosnilimab binds to PD-1 on a membrane proximal epitope that is on the opposite side of the receptor to that utilized by PD-L1 for binding, and thus preserves the ability of PD-L1 to agonize PD-1. In the setting of T cell activation, rosnilimab binding has been shown to induce agonistic signaling and the recruitment of SHP2 to PD-1, in a manner similar to that by PD-L1. In preclinical assays, rosnilimab prevented T cell expansion in antigen-specific response assays to numerous antigens, demonstrating prevention of T cell expansion and reduction in the secretion of inflammatory cytokines associated with multiple T cell types implicated in inflammatory pathology when dysregulated. In addition to direct agonistic activity, rosnilimab is an IgG1k antibody with effector function that can drive targeted depletion of PD-1+ T cells via the induction of antibody-dependent cellular cytotoxicity (ADCC). We believe this component of the mechanism of rosnilimab may provide more durable immune modulation by effectively eliminating the most pathogenic antigen-specific T cells in the setting of autoimmunity and inflammation. Genetic mutations in the PD-1 pathway are known to be associated with increased susceptibility to human inflammatory diseases, and hence we believe that rosnilimab is applicable to diseases where PD-1 checkpoint receptor function may be insufficient to maintain immune homeostasis.

We announced positive top-line data from a healthy volunteer Phase 1 trial of rosnilimab in November 2021. A total of 144 subjects were enrolled in the randomized, double-blind, placebo-controlled healthy volunteer Phase 1 trial, where single ascending dose (SAD) cohorts were administered single subcutaneous or intravenous (“IV”) doses of rosnilimab up to 600mg or placebo, while multiple ascending dose (MAD) cohorts received four weekly subcutaneous doses of rosnilimab ranging up to 400mg or placebo. Rosnilimab was generally well-tolerated and no dose limiting toxicities were observed. Two serious adverse events were reported in single dose cohorts, including obstructive pancreatitis in a placebo-dosed subject and COVID-19 infection in a rosnilimab-dosed subject leading to discontinuation. The COVID-19 infection was deemed unrelated to treatment. No serious adverse events were reported in subjects receiving multiple doses of rosnilimab or placebo. Rosnilimab demonstrated a favorable pharmacokinetic profile with an estimated two-week half-life for subcutaneous and IV routes of administration. Full PD-1 receptor occupancy was observed rapidly and was maintained for at least 30 days at or above 200mg following single subcutaneous rosnilimab doses. Rosnilimab pharmacodynamic activity demonstrated rapid and sustained reduction in the quantity and functional activity of PD-1+ T cells, which are known to be pathogenic drivers of inflammatory diseases. Conventional T (Tcon) cells (CD3+, CD25 low) PD-1+, which represented approximately 25% of peripheral T cells at baseline, were reduced by 50%, including in both CD4+ and CD8+ subsets, in a dose-dependent manner and in correlation with receptor occupancy. This effect was maximized on high-PD-1+ Tcon cells, which represented approximately 5% of peripheral T cells, with 90% reduction relative to baseline. Conversely, total T cells (CD3+), total Tcon cells (CD3+, CD25low) and total regulatory T (Treg) cells (CD3+, CD4+, CD25 bright, CD127-) were unchanged (<5% change from baseline), resulting in a

consistent ratio of PD-1+ Tcon cells to total Treg cells post-treatment in healthy volunteers. No effect (<5% reduction from baseline) was observed on any of the aforementioned cell types in placebo-dosed subjects.

We plan to conduct a randomized placebo-controlled multi-hundred patient global Phase 2b trial assessing three dose levels of subcutaneously administrated rosnilimab in moderate-to-severe RA for approximately six months on well-established endpoints including ACR 20/50/70 and DAS28. We expect to initiate this trial in the third quarter of 2023 with top-line interim data anticipated by mid-year 2025. We also plan to conduct a second global Phase 2 trial, in an indication to be announced, with trial initiation anticipated by the end of 2023.

During the fourth quarter of 2021, we initiated AZURE, a randomized placebo-controlled 45-patient Phase 2 trial of rosnilimab in moderate-to-severe alopecia areata patients. We conducted an interim review of blinded data in December 2022 which demonstrated robust reductions in peripheral PD-1+ T cells, including PD-1 high T cells reduction of >80%, across blinded pooled rosnilimab patients and placebo patients, which is consistent with observations in the healthy volunteer Phase 1 trial of >90% in rosnilimab treated patients. The blinded data suggests rosnilimab administration was generally safe and well tolerated. Interim results suggest that target improvement in severity of alopecia tool (SALT) was not achieved potentially due to an inadequate tested dose level, limited duration of treatment, and/or complexity of disease biology including the hair growth cycle. Further development in alopecia areata will not be pursued. The unblinded final results will be available in second half of 2023.

ANB032

ANB032 is designed to augment BTLA signaling, which is broadly applicable to human inflammatory diseases associated with lymphoid and myeloid immune cell dysregulation. Genetic studies have demonstrated that BTLA pathway mutations increase human susceptibility to multiple autoimmune diseases and insufficient BTLA signaling can lead to dysregulated T or B cell responses and changes in the function of dendritic cells. BTLA modulates signaling of HVEM, governing HVEM’s interaction with its natural ligands, including LIGHT. Polymorphisms in BTLA or molecules in the BTLA pathway such as HVEM are associated with inflammatory diseases, including aberrant T cell activity, B cell activity and dysregulation of downstream humoral immune responses (IgE, IgG secretion). Similarly, BTLA knockout animals have spontaneous or enhanced severity of inflammatory disease, demonstrating aberrant T cell activity, B cell activity and dysregulation of pathogenic antibody responses upon immunization. ANB032 is anticipated to down-modulate the activity of T cells, B cells and dendritic cells via several potential mechanisms: BTLA agonistic activity, stabilization of the interaction of BTLA and HVEM in cis which prevents pro-inflammatory signaling mediated by HVEM ligands such as LIGHT, and abrogation of pro-inflammatory HVEM signaling mediated by BTLA in trans.

We announced positive top-line data from a healthy volunteer Phase 1 trial of ANB032, under a CTN, in April 2022. A total of 96 subjects were enrolled in the randomized, double-blind, placebo-controlled healthy volunteer Phase 1 trial, where single ascending dose (SAD) cohorts received subcutaneous or IV single doses of ANB032 or placebo, while multiple ascending dose (MAD) cohorts received four weekly subcutaneous doses of ANB032 or placebo. ANB032 was generally well-tolerated and no dose limiting toxicities were observed. No serious adverse events were reported. ANB032 demonstrated a favorable pharmacokinetic profile with an estimated two-week half-life for subcutaneous and IV routes of administration. Full PD-1 receptor occupancy was observed rapidly and was maintained for at least 30 days.

In in vitro studies, ANB032 pharmacodynamic activity demonstrated inhibition of T cell proliferation and reduction in inflammatory cytokine secretion (Th1, Th2, Th17). While Th2 targeted therapies provide benefit to patients with chronic moderate-to-severe atopic dermatitis (AD), there is compelling evidence that AD is broader than a Th2 driven disease, as Th1, Th17 and other cell types, including dendritic cells, contribute significantly to the pathogenesis. ANB032 inhibition of inflammatory Th1, Th2 and Th17 activity, and modulation of additional cell types such as B cells and dendritic cells, creates the potential for broader, deeper and more durable responses than more narrowly targeted interventions.

We plan to conduct a randomized placebo-controlled 160 patient Phase 2 trial assessing three dose levels of subcutaneously administrated ANB032 in moderate-to-severe AD for 12 weeks on well-established endpoints including EASI75 and IGA 0/1. We expect to initiate this clinical trial in the second quarter of 2023 with top-line interim data anticipated by the end of 2024.

ANB033

ANB033 targets CD122, the common beta subunit shared by the IL-15 and IL-2 receptors. IL-15 signaling mediates the survival and maintenance of tissue resident memory T cells (TRM). The presence of long-lived and persistent TRM has been shown to drive tissue-specific immune-mediated inflammation. TRM are present in the skin in dermatologic diseases, where defined borders of inflammation often recur. TRM are also observed in other tissue-specific inflammatory disorders including gastroenterology, rheumatology and respiratory. ANB033 is designed with an affinity to CD122 that inhibits IL-15 signaling, leading to death of pathogenic TRM cells in diseased tissue, with the potential to achieve and maintain remission of inflammation through the elimination of these disease-causing cells. In addition, ANB033 inhibits IL-2 signaling through the

low affinity IL-2 receptor (comprised of CD122 and the common gamma subunit, CD132) expressed on T cells, while sparing regulatory T cells which express the high affinity IL-2 receptor (comprised of CD122, CD132 and the alpha receptor subunit for IL-2, CD25). This drives reduction of pathogenic T cell numbers while sparing or potentially enhancing regulatory T cell numbers. We anticipate submitting an IND for a Phase 1 clinical trial with ANB033 during the first half of 2024.

Imsidolimab

Imsidolimab inhibits the interleukin-36 receptor (IL-36R) and is being developed for the treatment of GPP. We completed a Phase 1 clinical trial in healthy volunteers, which was presented at the European Academy of Allergy and Clinical Immunology in 2018, where imsidolimab was well-tolerated, no dose-limiting toxicities were observed, and no serious adverse events were reported. In July 2020, the FDA granted Orphan Drug Designation for imsidolimab for the treatment of patients with GPP. We completed an open-label, multi-dose, single-arm Phase 2 clinical trial of imsidolimab in 8 GPP patients, also referred to as the GALLOP clinical trial, where top-line data through week 16 was presented at the European Academy of Dermatology and Venerology (EADV) Congress in October 2021.

We have initiated two Phase 3 trials for imsidolimab for GPP. The first, called GEMINI-1, will enroll approximately 45 moderate-to-severe GPP patients, each undergoing an active flare at baseline, which will be randomized equally to receive a single dose of 750mg IV imsidolimab, 300mg IV imsidolimab, or placebo. The primary endpoint of the Phase 3 program is the proportion of patients achieving clear or almost clear skin as determined by a GPPPGA score of zero or 1 at week 4 of GEMINI-1. Patients completing the GEMINI-1 trial will subsequently be enrolled in GEMINI-2, our second Phase 3 trial for imsidolimab in GPP, where they will receive monthly doses of 200mg subcutaneous imsidolimab or placebo depending upon whether they are responders, partial responders or non-responders to treatment under GEMINI-1. The objective of GEMINI-2 is to assess the efficacy and safety of imsidolimab after 3 years of monthly dosing. Top-line data from an interim analysis of GEMINI-1 is anticipated in the fourth quarter of 2023.

We announced in August 2022 that we intend to complete execution of our Phase 3 program in GPP and out-license imsidolimab prior to potential FDA approval.

Etokimab

Etokimab inhibits IL-33 function and acts upstream of key cell types involved in atopy and the subsequent release of Th2 cytokines. IL-33 is a pro-inflammatory cytokine that signals through the ST2 receptor, which multiple studies suggest serves as a central mediator of various immune responses leading to Th2-type inflammatory disorders, including asthma, COPD and atopic diseases. Individuals with asthma symptoms express higher levels of IL-33 than healthy control subjects. IL-33 initiates a diverse array of cellular immune responses, including the activation of mast cells, basophils and eosinophils, leading to production of downstream cytokines, such as IL-4, IL-5 and IL-13, which are associated with atopic diseases. IL-33 also acts on Th2 effector cells and Innate Lymphoid Cell Type 2 (ILC2), two types of white blood cells that initiate and orchestrate atopic responses. We have no ongoing clinical trials of etokimab and announced in January 2023 that etokimab is available to out-license.

Multiple Company-discovered antibody programs have been advanced to preclinical and clinical milestones under our collaborations. Our collaborations include an immuno-oncology-focused collaboration with GSK.

Under the GSK Agreement, a Biologics License Application (BLA) for our most advanced partnered program, which is an anti-PD-1 antagonist antibody called JEMPERLI (dostarlimab), was approved by the FDA in April 2021 for the treatment of advanced or recurrent deficient mismatch repair endometrial cancer (dMMREC). In February 2023, the FDA granted full approval for this indication (from an accelerated approval). In addition, in April 2021 the European Medicines Agency (“EMA”) granted conditional marketing authorization in the European Union (EU) for JEMPERLI for use in women with mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) recurrent or advanced endometrial cancer who have progressed on or following prior treatment with a platinum containing regimen. A second FDA approval was received in August 2021 for JEMPERLI in pan-deficient mismatch repair tumors (PdMMRT). JEMPERLI is currently in Phase 3 trials for various solid tumor indications, including first-line advanced/recurrent endometrial cancer and first-line ovarian cancer.

In addition, under the collaboration, GSK is developing dostarlimab in combination with two other development programs from the GSK Agreement: cobolimab, an anti-TIM-3 antibody, and GSK40974386, an anti-LAG-3 antibody for multiple solid tumor indications. GSK is conducting a Phase 3 trial, COSTAR Lung, which is a randomized, open label 3-arm trial comparing cobolimab plus dostarlimab plus docetaxel to dostarlimab plus docetaxel to docetaxel alone in patients with advanced non-small-cell lung cancer (“NSCLC”) who have progressed on prior anti-PD-(L)1 therapy and chemotherapy.

In June 2021, GSK estimated potential peak annual global JEMPERLI sales on a non-risk adjusted basis of £1-£2 billion for currently approved indications and first-line use in endometrial and ovarian cancer only.

Our Product Candidates

The following table summarizes certain key information about our wholly-owned product candidates:

Our Strategy

We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics. Our immune cell modulating antibodies, developed internally with our antibody research platform, modulate key nodes governing the body’s regulation of inflammation and autoimmunity. Dysregulated immune responses may result in abnormal and pathological inflammation in disorders with large and substantially underserved patient populations in the therapeutic areas of dermatology, rheumatology, gastroenterology, respiratory and neurology. The key elements of our strategy include:

•Enabling broad development of our immune cell modulator portfolio, including our checkpoint agonist programs, rosnilimab and ANB032, in indications including moderate-to-severe RA and AD, respectively.

•Generating in vitro and in vivo translational and clinical data to inform the potential differentiation of our molecules from in-class competitors and, relative to standard of care, treat patient populations most likely to have deeper and/or more durable responses by restoring immune balance.

•Facilitating the global commercialization of our checkpoint agonists while retaining rights in key therapeutic areas and/or commercial markets to enable us to become a fully integrated discovery, development and commercial organization.

•Continuing to leverage our research platform to generate potentially best-in-class antibodies against high-value immunological targets.

•Maximizing return on equity through execution against a multi-year capital and operating plan, including the potential for future royalty revenues from our GSK immuno-oncology collaboration and, where actionable, monetizing our legacy cytokine antagonist programs and enabling further external development and, potentially, commercialization.

As described in the section titled “Risk Factors” and elsewhere in this report, the clinical development of drug product candidates is subject to a wide range of risks and uncertainties, any of which could cause our actual development strategy or timeframes to vary.

Antibody Overview

Antibodies are complex proteins naturally generated by the immune system to neutralize foreign pathogens such as bacteria or viruses. B cells, a white blood cell type responsible for the generation of antibodies in response to pathogens, secrete billions of antibodies with different specificities into the bloodstream. Antibodies are structurally distinct Y-shaped proteins formed through the combination of two long proteins, called heavy chains, and two short proteins, called light chains. Each

heavy and light chain pair forms a binding site where the antibody specifically binds its target, otherwise known as an antigen, at the Fab domain of the antibody molecule. The specificity of each antibody to a target, and the potency of its binding strength to that target are defined by the amino acid sequences of heavy and light chains in the Fab domain of the antibody molecule. The other end of the antibody, called the Fc domain, is responsible for communication between the antibody and the rest of the immune system.

Therapeutic antibodies are typically non-naturally occurring, or recombinant, antibodies specifically developed to treat human diseases by binding to certain proteins, and thereby modulating key biological processes. Therapeutic antibodies are injectable products that are typically dosed subcutaneously or intravenously, unlike synthetic chemistry-based “small molecule” therapeutics that may also be administered orally. Therapeutic antibodies have the following key features that we believe make them more predictable than small molecules:

•Fab Domain. Due to the relatively large size and complex nature of the antibody Fab domain, antibodies generally bind with high specificity to the desired therapeutic target and tend to exhibit less off-target binding to unrelated proteins, which lowers the risk of unintended biological side effects such as toxicity. Because target proteins are typically larger than antibody Fab domains, antibodies can be generated against a variety of specific binding epitopes on a given single protein, which can alter the functional activity of the protein. For example, antibodies binding to unique epitopes on a single target protein can act as antagonists or agonists of the natural target protein function.

•Fc Domain. The Fc domain of an antibody is the tail region that interacts with cell surface receptors called Fc receptors and some proteins of the complement system. In humans, there are five Fc domains referred to as isotypes (IgA, IgD, IgM, IgG, IgE) and numerous Fc receptors expressed on specialized immune cells. Many therapeutic antibodies are subtypes of the IgG isotype and are chosen specifically to limit or induce immune system activity for therapeutic purposes. Engagement of Fc domains by specific Fc receptors can modulate biological activity, for example, by clustering the target protein on the cell surface in an immune synapse, leading to modulation of the target protein activity and hence altering the function of the cell expressing the target protein. Specific Fc domain and Fc receptor interactions may also trigger killing of a cell, often referred to as “effector function” of the antibody, via cytotoxic mechanisms depending on the cell type bearing the Fc receptor. In some therapeutic settings, mutations can be made to the Fc domain to weaken or entirely abrogate Fc receptor interactions. In creating the most efficacious therapeutic antibody, an appropriate Fc domain is often utilized to avoid or induce immune system activity that contributes to its broader mechanism of action. We believe that therapeutic antibodies can be significantly de-risked preclinically for specificity, toxicology, pharmacokinetics, and modulation of immune system activity, which is not generally true for small molecule drugs.

•Pharmacokinetics and Dosing Frequency. As complex proteins, antibodies are metabolized and distributed differently than small molecules. Full length antibodies tend to exhibit serum half-lives of seven to 24 days in humans, leading to bi-weekly or monthly dosing as typical practice for therapeutic antibodies.

•Potency and Dose Quantities. Antibodies are typically highly potent in binding affinity to their desired target, with binding dissociation constants in the low nanomolar to picomolar range. Hence, antibodies tend to be dosed at low amounts (less than 1 gram quantities per course of therapy).

Limitations of Competing Antibody Technologies

Despite the promise of antibodies as a therapeutic modality, historically it has been difficult and time consuming to generate therapeutic-grade antibodies utilizing competing antibody discovery technologies. Such technologies have relied primarily on mouse immunization methodologies (such as wild-type or engineered mice), microbial antibody display libraries (such as phage or yeast cell display) or human B cell screening to generate antibodies against therapeutic targets of interest. We believe the key limitations of these competitive approaches include insufficient diversity, lack of functional activity selection, and low potency. Antibody discovery technologies are often not utilized in combination, or iteratively in combination, or utilized in the appropriate immunological setting that would be conducive to co-discovery of appropriate Fab and Fc domains that work together to accomplish more challenging therapeutic mechanisms of action, such as immune cell modulation.

Our Antibody Research Platform

Our innovative antibody research platform is designed to discover and optimize therapeutic antibodies that are tailored to modulate immune function, whether they may be antagonists or immune cell modulators. Discovery and optimization occurs first on the Fab domain of the antibody where we often utilize a technology that replicates the natural process of somatic hyper mutation (“SHM”) employed by the human immune system through the expression of a key enzyme called activation-induced cytidine deaminase, (“AID”). SHM is a critical, endogenous process that generates the essential antibody diversity required to develop a natural immune response to pathogens, expanding the limited diversity encoded within human genomes to billions of antibody specificities. By coupling in vitro SHM with our mammalian cell system that simultaneously displays and secretes

antibodies, we believe SHM rapidly evolves in an iterative fashion the binding potency and function of antibodies to levels that we believe will be required for therapeutic use with high potency functional activity while simultaneously mitigating potential manufacturing liabilities.

In addition to optimizing the Fab domain of antibodies for therapeutic purposes using in vitro SHM, we also optimize the Fc domain of the antibody, when needed, to tailor it for specific activity. Appropriate Fc domains are utilized to reduce Fc receptor interactions or to optimize Fc receptor interactions, in combination with the Fab domain of the antibody, to specifically modulate immune cell function, engage effector function that kills specific targeted immune cells, or leverage a combination of both activities. We further optimize the overall antibody through humanization and removal of liabilities that could potentially affect the structure, stability, pharmacology, manufacturability or immunogenicity of the antibody.

Optimized antibodies are tested in an extensive suite of immune cell assays, using engineered cell lines, and more relevantly, primary human immune cells from healthy and diseased individuals that we believe most accurately recapitulates the conditions in which the antibody will need to have optimal activity in patients.

We believe that by combining the in vitro SHM discovery platform with an appropriate Fc domain, in combination with a suite of primary immune cell assays, and finally in vivo functional assessment, we effectively tailor antibody discovery to achieve a unique therapeutic benefit.

Collaborations

GlaxoSmithKline

In March 2014, we entered into a Collaboration and Exclusive License Agreement with GSK (the “GSK Agreement”) for the development and commercialization of therapeutic monospecific and bispecific antibodies that antagonize PD-1, TIM-3, LAG-3 and/or a fourth undisclosed checkpoint receptor. We received $17.0 million in upfront fees from GSK in March 2014, and in November 2014, we amended the agreement with GSK to include the development and commercialization of bispecific antibodies to another undisclosed target, for an additional upfront fee of $2.0 million. Both upfront fees were recognized over the same period that our research and development services for which we were reimbursed were performed, which was extended through December 31, 2016 by amendment of the GSK Agreement in February 2016.

For each of the targets under the GSK agreement, we are eligible to receive up to $273.0 million in milestone payments, which are comprised of $18.0 million for preclinical and clinical development milestone payments, $90.0 million upon certain regulatory events and $165.0 million upon worldwide commercial sales thresholds. In addition, GSK is obligated to pay us tiered royalties, ranging from 4% to 8%, for each product developed under the agreement, except in the case of JEMPERLI where the royalties payable will be 8% to 25% as described below, on annualized net sales of each antibody commercialized from the collaboration.

On October 23, 2020, we amended the GSK Agreement (the “2020 Amendment”). Under the 2020 Amendment, we were granted increased royalties upon sales of JEMPERLI (dostarlimab), an anti-PD-1 antagonist antibody under development by GSK for multiple oncological disorders, equal to 8% of Net Sales (as defined in the GSK Agreement) below $1.0 billion and from 12% up to 25% of Net Sales above $1.0 billion.The 2020 Amendment also provided for a one-time non-refundable cash payment of $60.0 million that we received in the fourth quarter of 2020. The $1.1 billion in cash milestone payments due under the GSK Agreement remain unchanged.Additionally, under the terms of the 2020 Amendment, GSK has agreed to certain diligence commitments with respect to the future development of JEMPERLI, and the parties have agreed to review such commitments under regular joint review committee meetings going forward.

In October 2021, we entered into the JEMPERLI Royalty Monetization Agreement (the “JEMPERLI Royalty Monetization Agreement”) with Sagard. Under the terms of the JEMPERLI Royalty Monetization Agreement, we received $250.0 million, upon closing in December 2021, in exchange for royalties payable to us under the GSK collaboration on annual global net sales of JEMPERLI below $1.0 billion, as well as certain milestone payments, starting in October 2021. The aggregate JEMPERLI royalties and certain future milestones to be received by Sagard under the JEMPERLI Royalty Monetization Agreement are capped at certain fixed multiples of the upfront payment based on time. For more information see Note 5 — Sale of Future Royalties in the accompanying notes to the consolidated financial statements.

This GSK Agreement, as amended, expires when no further payments are due to us, unless earlier terminated. Either party may terminate the GSK Agreement, as amended, in the event of an uncured material breach by the other party. GSK may terminate the GSK Agreement, as amended, at any time upon 90 days’ prior written notice to us.

Under the GSK Agreement, a Biologics License Application (“BLA”) for our most advanced partnered program, which is an anti-PD-1 antagonist antibody called JEMPERLI (dostarlimab), was approved by the FDA in April 2021 for the treatment of advanced or recurrent deficient mismatch repair endometrial cancer (dMMREC). In February 2023, the FDA granted full approval for this indication (from an accelerated approval). In addition, in April 2021 the European Medicines Agency (“EMA”) granted conditional marketing authorization in the European Union (“EU”) for JEMPERLI for use in women with mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) recurrent or advanced endometrial cancer who have progressed on or following prior treatment with a platinum containing regimen. A second FDA approval was received in August 2021 for JEMPERLI in pan-deficient mismatch repair tumors (PdMMRT). JEMPERLI is currently in Phase 3 trials for various solid tumor indications, including first-line advanced/recurrent endometrial cancer and first-line ovarian cancer.

In addition, under the collaboration, GSK is developing dostarlimab in combination with two other development programs from the GSK Agreement: cobolimab, an anti-TIM-3 antibody, and GSK40974386, an anti-LAG-3 antibody for multiple solid tumor indications. GSK is conducting a Phase 3 trial, COSTAR Lung, which is a randomized, open label 3-arm trial comparing cobolimab plus dostarlimab plus docetaxel to dostarlimab plus docetaxel to docetaxel alone in patients with advanced NSCLC who have progressed on prior anti-PD-(L)1 therapy and chemotherapy.

Bristol-Myers Squibb

In December 2011, we entered into a license and collaboration agreement (the “BMS Agreement”) with Celgene, now a part of Bristol-Myers Squibb (Celgene and Bristol-Myers Squibb are hereinafter referred to, collectively, as “BMS”), to develop therapeutic antibodies against multiple targets. We granted BMS 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 the agreement.

The BMS Agreement provided for an upfront payment of $6.0 million from BMS, which we received in 2011, and recognized through 2014, milestone payments of up to $53.0 million per target, low single-digit royalties on net sales of antibodies against each target, and reimbursement of specified research and development costs.

The BMS Agreement continues until our royalty rights on any BMS product resulting from the collaboration expire, which period will last at least ten years after any such product first goes to market. Either we or BMS may terminate the BMS Agreement in the event of an uncured material breach by the other party.

In-Licensing Agreements License Agreement with UKRI

In 2006, we entered into an exclusive worldwide license agreement with the Medical Research Council, which has subsequently been acquired by United Kingdom Research and Innovation (“UKRI”), to obtain rights to multiple patents and patent applications relating to fundamental discoveries with respect to SHM and AID. We since amended this license agreement to include additional subject matter and reflect the change in ownership. Under the terms of the agreement (the “UKRI Agreement”), we obtained an exclusive, worldwide, sub-licensable license under specified patent rights to manufacture, use, sell and commercialize products and methods covered by such patents for all fields of use. We are responsible for prosecution of the licensed patents and the development of therapeutic products covered by the intellectual property.

We are responsible for paying UKRI an annual fee of $55,000. Additionally, for each product developed and commercialized under the UKRI Agreement, we are obligated to pay UKRI up to an additional $175,000 upon the achievement of specified development milestone events and up to an additional $275,000 upon the achievement of specified regulatory milestone events. In addition, we owe UKRI royalties at 0.25% of annual net sales for worldwide sales on a product-by-product at or below $750.0 million and 1% of annual net sales of products worldwide above $750.0 million, payable on a country-by-country basis until the expiration of the last licensed patent covering such product in such country. Under this license agreement, we have rights to 10 patents worldwide as of December 31, 2022.

Unless earlier terminated, the UKRI Agreement will expire upon expiration of all royalty payment obligations under the UKRI Agreement. Either party may terminate the UKRI Agreement in the event of an uncured material breach by the other party or upon the occurrence of specified bankruptcy events for the other party. We may terminate the UKRI Agreement upon 60 days’ notice to UKRI.

License Agreement with Millipore

In May 2009, we signed a non-exclusive research and commercial license agreement with Millipore Corporation, or Millipore, to obtain a non-exclusive license to patents and patent applications directed to the ubiquitous chromatin opening elements technology for the expression of proteins, particularly antibodies, generated by us, which license may be sublicensed to our contractors and partners. Under the terms of the agreement, (the “Millipore Agreement”), we are obligated to pay Millipore $87,500 in annual license fees, adjusted annually for inflation using the Consumer Price Index. Additionally, for each product developed and commercialized under the Millipore Agreement, we are obligated to pay Millipore up to an additional $750,000 upon the achievement of specified development milestone events and up to an additional $4.4 million upon the achievement of specified commercial milestone events. We do not owe Millipore any royalties on net sales of products commercialized under the Millipore Agreement.

Unless affirmatively terminated by one of the parties, the Millipore Agreement will continue in effect. Either party may terminate the Millipore Agreement in the event of an uncured material breach by the other party. We may terminate the Millipore Agreement upon 90 days’ notice to Millipore.

Intellectual Property

Our intellectual property is critical to our business and we strive to protect it, including by obtaining and maintaining patent protection in the United States and internationally for our technology platform, product candidates, novel biological discoveries, epitopes, new therapeutic approaches and potential indications, and other inventions that are important to our business. In total, our patent portfolio, including patents to our technology platform licensed from UKRI, as well as patents co-owned with GSK consisted of approximately 82 issued patents and 90 pending patent applications as of December 31, 2022.

For our product candidates, generally we initially pursue patent protection covering compositions of matter including antibody sequences, methods of use, and methods of production. Throughout the development of our product candidates, we seek to identify additional means of obtaining patent protection that would potentially enhance commercial success.

The patent portfolios for our internal programs and platform technology are outlined below:

Rosnilimab

As of December 31, 2022, we owned 16 patent applications in various countries directed to the antibody sequence of rosnilimab and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that may issue from our pending applications could provide protection until June 2040.

ANB032

As of December 31, 2022, we owned one international (PCT) patent application and one U.S. provisional patent application directed to the antibody sequence of ANB032 and its variants, methods of use and related matters. We intend to prosecute the pending international patent application and file additional patent applications claiming priority to the U.S. provisional patent application, and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that may issue from our pending applications, or other patent applications claiming priority thereto, could provide protection until April 2043.

ANB033

As of December 31, 2022, we owned one pending U.S. provisional patent application directed to the antibody sequence of ANB033 and its variants, methods of use and related matters. We intend to file additional patent applications claiming priority to the U.S. provisional patent application, and pursue patent issuance, in key commercial markets where significant product sales may occur. Patents that may issue claiming priority to our provisional patent application could provide protection until November 2043.

Imsidolimab

As of December 31, 2022, we owned 24 patents and patent applications in various countries directed to the antibody sequence of imsidolimab and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or may issue from our pending applications could provide protection until May 2042.

Etokimab

As of December 31, 2022, we owned 17 patents and patent applications in various countries directed to the antibody sequence of etokimab and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or may issue from our pending applications could provide protection until January 2035.

Dostarlimab (GSK4057190)

As of December 31, 2022, we owned or co-owned 24 patents and patent applications in various countries directed to the antibody sequence of GSK4057190 (dostarlimab), an anti-PD-1 antagonist, and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or may issue from our pending applications could provide protection until June 2038.

Cobolimab (GSK4069889)

As of December 31, 2022, we owned or co-owned 23 patents and patent applications in various countries directed to the antibody sequence of GSK4069889 (cobolimab), an anti-TIM-3 antagonist, and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or may issue from our pending applications could provide protection until November 2037.

GSK4074386

As of December 31, 2022, we owned or co-owned 37 patents and patent applications in various countries directed to the antibody sequence of GSK4074386, an anti-LAG-3 antagonist, and its variants, methods of use and related matters. We intend to prosecute our pending applications and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or may issue from our pending applications could provide protection until April 2038.

Platform Technology

Our platform technology is covered by U.S. and foreign issued patents, emanating from our in-licensed portfolio and wholly-owned portfolio, in various jurisdictions.

Our portfolio includes patents directed to platform technology related inventions associated with antibody library design, antibody humanization, mammalian cell display and secretion, and other technical attributes relating to the discovery, maturation and optimization of antibodies using our technology platform. Patents relating to our platform technology that have been issued to date provide protection through May 2033.

Other Intellectual Property Matters

The patent positions of biotechnology companies like ours are generally uncertain and involve complex legal, scientific and factual questions. In addition, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted after issuance. Consequently, we may not obtain or maintain adequate patent protection for any of our product candidates or for our technology platform. We cannot predict whether the patent applications we are currently pursuing will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Any patents that we hold may be challenged, circumvented or invalidated by third parties. For a more comprehensive discussion of the risks related to our intellectual property, please see “Risk Factors— Risks Related to Our Intellectual Property.”

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is 20 years from the earliest date of filing a non-provisional patent application related to the patent. A U.S. patent also may be accorded a patent term adjustment (“PTA”) under certain circumstances to compensate for delays in obtaining the patent from the U.S. Patent and Trademark Office (“USPTO”). In some instances, such a PTA may result in a U.S. patent term extending beyond 20 years from the earliest date of filing a non-provisional patent application related to the U.S. patent. In addition, the term of a U.S. patent that covers an FDA-approved drug may also be eligible for patent term extension, which permits patent term restoration as compensation for the patent term lost during the FDA regulatory review process. The Hatch-Waxman Act permits a patent term extension of up to five years beyond the expiration of the patent. The length of the patent term extension is related to the length of time the drug is under regulatory review. Patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval and only one patent applicable to an approved drug may be extended. Similar provisions are available in Europe and

other foreign jurisdictions to extend the term of a patent that covers an approved drug. In the future, if and when our products receive FDA approval, we expect to apply for patent term extensions on patents covering those products. We plan to seek patent term extensions to any of our issued patents in any jurisdiction where these are available, however there is no guarantee that the applicable authorities, including the FDA in the United States, will agree with our assessment of whether such extensions should be granted, and if granted, the length of such extensions.

We also rely on trade secrets relating to our technology platform and product candidates and seek to protect and maintain the confidentiality of proprietary information to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. Although we take steps to protect our proprietary information and trade secrets, including through contractual means with our employees and consultants, third parties may independently develop substantially equivalent proprietary information and techniques or otherwise gain access to our trade secrets or disclose our technology. Thus, we may not be able to meaningfully protect our trade secrets.

It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. Our agreements with employees also provide that all inventions conceived by the employee in the course of employment with us or from the employee’s use of our confidential information are our exclusive property.

Manufacturing

We must manufacture drug product for clinical trial use in compliance with current good manufacturing practices (“cGMP”). The cGMP regulations include requirements relating to organization of personnel, buildings and facilities, equipment, control of components and drug product containers and closures, production and process controls, packaging and labeling controls, holding and distribution, laboratory controls, records and reports, and returned or salvaged products. The manufacturing facilities for our product candidates must meet cGMP requirements and FDA satisfaction before any product is approved and we can manufacture commercial products. Our third-party manufacturers will also be subject to periodic inspections of facilities by the FDA and other authorities, including procedures and operations used in the testing and manufacture of our products to assess our compliance with applicable regulations.

Our internal manufacturing capabilities include non-cGMP antibody and reagent production using small scale quantities for characterization and in vitro and in vivo preclinical assessment of product candidates. We do not have and we do not currently plan to acquire or develop the facilities or capabilities to manufacture cGMP drug substance or filled drug product for use in human clinical trials.

We rely on third-party manufacturers to generate cGMP-grade cell lines and will rely on them to produce cGMP drug product required for our clinical trials, and we expect to continue to rely on third parties to manufacture clinical trial drug supplies for the foreseeable future. We also contract with additional third parties for the filling, labeling, packaging, storage and distribution of investigational drug products. We have personnel with significant technical, manufacturing, analytical, quality, including cGMP, and project management experience to oversee our third-party manufacturers and to manage manufacturing and quality data and information for regulatory compliance purposes. While our contract manufacturers have not yet produced commercially-approved cGMP batches of our product candidates, they have previously manufactured products for other companies in compliance with cGMP and have been previously inspected by regulatory authorities for compliance with cGMP standards. Similarly, our personnel have had experience with cGMP at previous positions.

Failure to comply with statutory and regulatory requirements subjects a manufacturer to possible legal or regulatory action, including warning letters, the seizure or recall of products, injunctions, consent decrees placing significant restrictions on or suspending manufacturing operations and civil and criminal penalties. These actions could have a material impact on the availability of our products. Contract manufacturers often encounter difficulties involving production yields, quality control and quality assurance, as well as shortages of qualified personnel.

Competition

The biotechnology and pharmaceutical industries are characterized by continuing technological advancement and significant competition. While we believe that our product candidates, technology, knowledge, experience and scientific resources provide us with competitive advantages, we face competition from major pharmaceutical and biotechnology companies, academic institutions, governmental agencies and public and private research institutions, among others. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future. Key product features that would affect our ability to effectively compete with other therapeutics include the efficacy, safety and convenience of our products and the ease of use and effectiveness of any companion diagnostics. The level of generic competition and the availability of reimbursement from government and other third-party payors will also significantly affect the pricing and competitiveness of our products. Our competitors also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market.

Many of the companies against which we may compete have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

Specifically, there are several companies developing or marketing treatments that may be approved for the same indications and/or diseases as our product candidates, including major pharmaceutical companies.

For our anti-PD-1 agonist antibody program, our competitors include other anti-PD-1 agonist antibodies peresolimab (Eli Lilly) in Phase 2b development for the treatment of rheumatoid arthritis, JNJ-67484703 (Janssen) in Phase 2 development, a PD-1 agonist antibody (Boehringer Ingelheim) in Phase 1 development, PT627 and PT001 (Pandion Therapeutics, which has been acquired by Merck) in preclinical development, and MB151 (MiroBio, which has been acquired by Gilead) in preclinical development. Our competitors in moderate-to-severe rheumatoid arthritis include monoclonal antibodies targeting anti-TNF (Humira; Abbvie), IL-6 (Actemra; Roche and Kevzara; Regeneron), CD-80/86 (Orencia; BMS), CD-20 (Rituxan; Roche), and janus kinase inhibitors (Rinvoq; AbbVie, Olumiant; Eli Lilly, and Xeljanz; Pfizer).

For our anti-BTLA agonist antibody program, our competitors include other anti-BTLA agonist antibodies LY3361237 (Eli Lilly) in Phase 2 development, which has demonstrated efficacy in treatment of systemic lupus erythematosus as measured by the cutaneous lupus erythematosus disease area and severity index (CLASI), and MB272 (MiroBio, in Phase 1 development which has been acquired by Gilead). Our competitors in moderate-to-severe atopic dermatitis include topical and oral corticosteroids, calcineurin inhibitors (Protopic; LEO Pharma and Elidel; Bausch Health), monoclonal antibodies targeting IL-4/13 (Dupixent; Regeneron/Sanofi), IL-13 (Adbry; LEO Pharma and lebrikizumab; Eli Lilly), IL-31 (nemolizumab; Galderma), OX-40L (amlitelimab; Sanofi), and janus kinase inhibitors (Rinvoq; AbbVie and abrocitinib; Pfizer).

For our anti-CD122 antagonist antibody program, our competitors include one other anti-CD122 antagonist antibody, auremolimab (Villaris Therapeutics, which has been acquired by Incyte), currently in preclinical development, and an anti-IL-15 monoclonal antibody, AMG 714 (Amgen), currently in Phase 2 development for the treatment of vitiligo.

For imsidolimab in the treatment of GPP, our competitors include one other anti-IL-36 receptor antibody called SPEVIGO or spesolimab (Boehringer Ingelheim), recently approved for GPP flares in adults.

Government Regulation and Product Approval

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the EU, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

FDA approval process

In the United States, pharmaceutical products are subject to extensive regulation by the FDA. The Federal Food, Drug, and Cosmetic Act (“FDC Act”), and other federal and state statutes and regulations, govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting, sampling, and import and export of pharmaceutical products. Biological products used for the prevention, treatment, or cure of a disease or condition of a human being are subject to regulation under the FDC Act,

except the section of the FDC Act which governs the approval of new drug applications (“NDAs”). Biological products are approved for marketing under provisions of the Public Health Service Act (“PHSA”), via a BLA. However, the application process and requirements for approval of BLAs are similar to those for NDAs, and biologics are associated with similar approval risks and costs as drugs. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as clinical hold, FDA refusal to approve pending NDAs or BLAs, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties, and criminal prosecution.

Biological product development for a new product or certain changes to an approved product in the United States typically involves preclinical laboratory and animal tests, the submission to the FDA of an investigational new drug application (“IND”), which must become effective before clinical testing may commence in the United States, and adequate and well-controlled clinical trials to establish the safety and effectiveness of the drug for each indication for which FDA approval is sought. Satisfaction of FDA premarket approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity, and novelty of the product or disease.

Preclinical tests include laboratory evaluation of product chemistry, formulation, and toxicity, as well as animal trials to assess the characteristics and potential safety and efficacy of the product. The conduct of the preclinical tests must comply with federal regulations and requirements, including good laboratory practices (“GLPs”). The results of preclinical testing are submitted to the FDA as part of an IND along with other information, including information about product chemistry, manufacturing and controls, and a proposed clinical trial protocol. Long term preclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has neither commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin. Clinical trials involve the administration of the investigational biologic to healthy volunteers or patients under the supervision of a qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with good clinical practices (“GCPs”), an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators, and monitors; as well as (iii) under protocols detailing the objectives of the trial, the parameters to be used in monitoring safety, and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of the IND.

The FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other sanctions if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. The trial protocol and informed consent information for patients in clinical trials must also be submitted to an institutional review board (“IRB”) for approval. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions.

Clinical trials to support BLAs for marketing approval are typically conducted in three sequential phases, but the phases may overlap. In Phase 1, the initial introduction of the biologic into healthy human subjects or patients, the product is tested to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence on effectiveness. Phase 2 usually involves clinical trials in a limited patient population to determine the effectiveness of the drug or biologic for a particular indication, dosage tolerance, and optimal dosage, and to identify common adverse effects and safety risks. If a compound demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 clinical trials are undertaken to obtain the additional information about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit the FDA to evaluate the overall benefit risk relationship of the drug or biologic and to provide adequate information for the labeling of the product. In most cases, the FDA requires two adequate and well-controlled Phase 3 clinical trials to demonstrate the efficacy of the biologic. A single Phase 3 clinical trial may be sufficient in rare instances, including (i) where the clinical trial is a large multicenter clinical trial demonstrating internal consistency and a statistically persuasive finding of a clinically meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and confirmation of the result in a second clinical trial would be practically or ethically impossible or (ii) when in conjunction with other confirmatory evidence.

After completion of the required clinical testing, a BLA is prepared and submitted to the FDA. FDA approval of the BLA is required before marketing of the product may begin in the United States. The BLA must include the results of all preclinical, clinical, and other testing and a compilation of data relating to the product’s pharmacology, chemistry, manufacture, and controls. The cost of preparing and submitting a BLA is substantial. The submission of most BLAs is additionally subject to a substantial application user fee, and the applicant under an approved BLA is also subject to annual product and establishment user fees. These fees are typically increased annually. The FDA has 60 days from its receipt of a BLA to determine whether the application will be accepted for filing based on the agency’s threshold determination that it is sufficiently complete to permit substantive review. Once the submission is filed, the FDA begins an in-depth review. The FDA has agreed to certain performance goals in the review of BLAs. Most such applications for standard review biologic products are reviewed within 10 months of the date the BLA is filed with the FDA; most applications for priority review biologics are reviewed within

six months of the date the BLA is filed with the FDA. Priority review can be applied to a biologic that the FDA determines has the potential to treat a serious or life-threatening condition and, if approved, would be a significant improvement in safety or effectiveness compared to available therapies. The review process for both standard and priority review may be extended by the FDA for three additional months to consider certain late-submitted information or information intended to clarify information already provided in the submission.

The FDA may also refer applications for novel biologic products, or biologic products that present difficult questions of safety or efficacy, to an advisory committee—typically a panel that includes clinicians and other experts—for review, evaluation, and a recommendation as to whether the application should be approved. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations. Before approving a BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. Additionally, the FDA will inspect the facility or the facilities at which the biologic product is manufactured. The FDA will not approve the product unless compliance with cGMP is satisfactory and the BLA contains data that provide substantial evidence that the biologic is safe, pure, potent and effective in the indication studied.

After the FDA evaluates the BLA and the manufacturing facilities, it issues either an approval letter or a complete response letter. A complete response letter generally outlines the deficiencies in the submission and may require substantial additional testing, or information, in order for the FDA to reconsider the application. If, or when, those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the BLA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. An approval letter authorizes commercial marketing of the biologic with specific prescribing information for specific indications. As a condition of BLA approval, the FDA may require a risk evaluation and mitigation strategy (“REMS”) to help ensure that the benefits of the biologic outweigh the potential risks. REMS can include medication guides, communication plans for health care professionals, and elements to assure safe use (“ETASU”). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the product. Moreover, product approval may require substantial post-approval testing and surveillance to monitor the product’s safety or efficacy.

Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing. Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of a new BLA or BLA supplement before the change can be implemented. A BLA supplement for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing BLA supplements as it does in reviewing BLAs.

Foreign clinical studies to support an IND

The FDA will accept as support for an IND a well-designed, well-conducted, non-IND foreign clinical study if it was conducted in accordance with GCP and the FDA is able to validate the data from the study through an onsite inspection, if necessary. A sponsor or applicant who wishes to rely on a non-IND foreign clinical study to support an IND must submit the following supporting information to the FDA to demonstrate that the study conformed to GCP:

•the investigator’s qualifications;

•a description of the research facilities;

•a detailed summary of the protocol and study results and, if requested, case records or additional background data;

•a description of the drug substance and drug product, including the components, formulation, specifications, and, if available, the bioavailability of the drug product;

•information showing that the study is adequate and well controlled;

•the name and address of the independent ethics committee that reviewed the study and a statement that the independent ethics committee meets the required definition;

•a summary of the independent ethics committee’s decision to approve or modify and approve the study, or to provide a favorable opinion;

•a description of how informed consent was obtained;

•a description of what incentives, if any, were provided to subjects to participate;

•a description of how the sponsors monitored the study and ensured that the study was consistent with the protocol;

•a description of how investigators were trained to comply with GCP and to conduct the study in accordance with the study protocol; and

•a statement on whether written commitments by investigators to comply with GCP and the protocol were obtained.

Disclosure of clinical trial information

Sponsors of clinical trials of FDA-regulated products, including biological products, are required to register and disclose certain clinical trial information. Information related to the product, patient population, phase of investigation, trial sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are also obligated to discuss the results of their clinical trials after completion. Disclosure of the results of these clinical trials can be delayed in certain circumstances for up to two years after the date of completion of the clinical trial. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs.

Pediatric information

Under the Pediatric Research Equity Act (“PREA”), NDAs or BLAs or supplements to NDAs or BLAs must contain data to assess the safety and effectiveness of the biological product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the biological product is safe and effective. The FDA may grant full or partial waivers, or deferrals, for submission of data. Unless otherwise required by regulation, the PREA does not apply to any biological product for an indication for which Orphan Drug Designation has been granted.

The Best Pharmaceuticals for Children Act (“BPCA”), provides sponsors of NDAs with an additional six-month period of market exclusivity for all unexpired patent or non-patent exclusivity on all forms of the drug containing the active moiety if the sponsor submits results of pediatric studies specifically requested by the FDA under BPCA within required timeframes. The BPCA provides sponsors of BLAs an additional six-month extension for all unexpired non-patent market exclusivity on all forms of the biological containing the active moiety pursuant to the BPCA if the conditions under the BPCA are met.

Additional controls for biologics

To help reduce the increased risk of the introduction of adventitious agents, the PHSA emphasizes the importance of manufacturing controls for products whose attributes cannot be precisely defined. The PHSA also provides authority to the FDA to immediately suspend licenses in situations where there exists a danger to public health, to prepare or procure products in the event of shortages and critical public health needs, and to authorize the creation and enforcement of regulations to prevent the introduction or spread of communicable diseases in the United States and between states.

After a BLA is approved, the product may also be subject to official lot release as a condition of approval. As part of the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each lot of product to the FDA together with a release protocol showing a summary of the history of manufacture of the lot and the results of all of the manufacturer’s tests performed on the lot. The FDA may also perform certain confirmatory tests on lots of some products, such as viral vaccines, before releasing the lots for distribution by the manufacturer.

In addition, the FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of biological products. As with drugs, after approval of biologics, manufacturers must address any safety issues that arise, are subject to recalls or a halt in manufacturing, and are subject to periodic inspection after approval.

Patent term restoration

After approval, owners of relevant drug or biologic patents may apply for up to a five year patent extension. The allowable patent term extension is calculated as half of the drug’s testing phase—the time between IND application and NDA or BLA submission—and all of the review phase—the time between NDA or BLA submission and approval up to a maximum of five years. The time can be shortened if FDA determines that the applicant did not pursue approval with due diligence. The total patent term after the extension may not exceed 14 years.

For patents that might expire during the application phase, the patent owner may request an interim patent extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For each interim patent extension granted, the post-approval patent extension is reduced by one year. The director of the USPTO must determine that approval of the drug covered by the patent for which a patent extension is being sought is likely. Interim patent extensions are not available for a drug or biologic for which an NDA or BLA has not been submitted.

Biosimilars

The Biologics Price Competition and Innovation Act of 2009 (“BPCIA”), created an abbreviated approval pathway for biological products shown to be highly similar to or interchangeable with an FDA licensed reference biological product. Biosimilarity sufficient to reference a prior FDA-approved product requires that there be no differences in conditions of use, route of administration, dosage form, and strength, and no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency. Biosimilarity must be shown through analytical trials, animal trials, and a clinical trial or trials, unless the Secretary of the U.S. Department of Health and Human Services (“HHS”) waives a required element. A biosimilar product may be deemed interchangeable with a prior approved product if it meets the higher hurdle of demonstrating that it can be expected to produce the same clinical results as the reference product and, for products administered multiple times, the biologic and the reference biologic may be switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic. The first biosimilar was approved by the FDA in 2015, and the first interchangeable product was approved in 2021.

A reference biologic is granted 12 years of exclusivity from the time of first licensure of the reference product, and no application for a biosimilar can be submitted for four years from the date of licensure of the reference product. The first biologic product submitted under the abbreviated approval pathway that is determined to be interchangeable with the reference product has exclusivity against a finding of interchangeability for other biologics for the same condition of use for the lesser of (i) one year after first commercial marketing of the first interchangeable biosimilar, (ii) 18 months after the first interchangeable biosimilar is approved if there is no patent challenge, (iii) 18 months after resolution of a lawsuit over the patents of the reference biologic in favor of the first interchangeable biosimilar applicant, or (iv) 42 months after the first interchangeable biosimilar’s application has been approved if a patent lawsuit is ongoing within the 42-month period.

Post-approval requirements

Once a BLA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA closely regulates the post-approval marketing and promotion of biologics, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet.

Biologics may be marketed only for the approved indications and in accordance with the provisions of the approved labeling. Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, may require a submission to and approval by the FDA before the change can be implemented. A BLA supplement for a new indication typically requires clinical data similar to that in the original application and similar procedures and actions in reviewing BLA or supplements as in reviewing BLAs.

Adverse event reporting and submission of periodic reports are required following FDA approval of a BLA. The FDA also may require post-marketing testing, known as Phase 4 testing, REMS, and surveillance to monitor the effects of an approved product, or the FDA may place conditions on an approval that could restrict the distribution or use of the product. In addition, quality control, biological product manufacture, packaging, and labeling procedures must continue to conform to cGMPs after approval. Biologic manufacturers and certain of their subcontractors are required to register their establishments with the FDA and certain state agencies. Registration with the FDA subjects entities to periodic unannounced inspections by the FDA, during which the agency inspects manufacturing facilities to assess compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money, and effort in the areas of production and quality-control to maintain compliance with cGMPs. Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing, or if previously unrecognized problems are subsequently discovered. In addition, biological product manufacturers in the U.S. must comply with applicable provisions of the Drug Supply Chain Security Act and provide and receive product tracing information, maintain appropriate licenses, ensure they only work with other properly licensed entities and have procedures in place to identify and properly handle suspect and illegitimate products.

FDA regulation of companion diagnostics

If use of an in vitro diagnostic is essential for safe and effective use of a drug or biologic product, then the FDA generally will require approval or clearance of the diagnostic, known as a companion diagnostic, at the same time that the FDA approves the therapeutic product. The review of an in vitro companion diagnostic in conjunction with the review of a biologic involves coordination of review by the FDA’s Center for Biologics Evaluation and Research and by the FDA’s Center for Devices and Radiological Health. Pursuing FDA approval of an in vitro companion diagnostic would require us to obtain a premarket approval (“PMA”). The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are

subject to an application fee, which exceeds $250,000 for most PMAs. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (“QSR”), which imposes elaborate testing, control, documentation and other quality assurance requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA application submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the U.S.

Other U.S. health care laws and compliance requirements

In the United States, our activities are potentially subject to regulation by various federal, state and local authorities in addition to the FDA, including but not limited to, the Centers for Medicare and Medicaid Services (“CMS”), other divisions of the HHS (such as the Office of Inspector General), the U.S. Department of Justice (“DOJ”), and individual U.S. Attorney offices within the DOJ, and state and local governments. For example, sales, marketing and scientific/educational grant programs may have to comply with the anti-fraud and abuse provisions of the Social Security Act, anti-kickback statutes, false claims laws, the privacy and security provisions of the Health Insurance Portability and Accountability Act (“HIPAA”), and similar state laws, each as amended, as applicable.

The federal Anti-Kickback Statute prohibits, among other things, any person or entity, from knowingly and willfully offering, paying, soliciting or receiving any remuneration, directly or indirectly, overtly or covertly, in cash or in kind, to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any item or service reimbursable under Medicare, Medicaid or other federal health care programs. The term remuneration has been interpreted broadly to include anything of value. The Anti-Kickback Statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other. There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from prosecution. The exceptions and safe harbors are drawn narrowly and practices that involve remuneration that may be alleged to be intended to induce prescribing, purchasing or recommending may be subject to scrutiny if they do not qualify for an exception or safe harbor. Failure to meet all of the requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the Anti-Kickback Statute. Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all of its facts and circumstances. Our practices may not in all cases meet all of the criteria for protection under a statutory exception or regulatory safe harbor.

Additionally, the intent standard under the Anti-Kickback Statute was amended by the Patient Protection and Affordable Care Act (“ACA”) to a stricter standard such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the ACA codified case law that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal False Claims Act (discussed below).

The civil monetary penalties statute imposes penalties against any person or entity that, among other things, is determined to have presented or caused to be presented a claim to a federal health program that the person knows or should know is for an item or service that was not provided as claimed or is false or fraudulent.

Federal false claims and false statement laws, including the federal False Claims Act, prohibit, among other things, any person or entity from knowingly presenting, or causing to be presented, a false or fraudulent claim for payment to, or approval

by, the federal health care programs, including Medicare and Medicaid, or knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the federal government. As a result of a modification made by the Fraud Enforcement and Recovery Act of 2009, a claim includes “any request or demand” for money or property presented to the U.S. government. Recently, several pharmaceutical and other health care companies have been prosecuted under these laws for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the companies’ marketing of the product for unapproved, and thus generally non-reimbursable, uses.

HIPAA created additional federal criminal statutes that prohibit, among other things, knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or property owned by, or under the control or custody of, any health care benefit program, including private third-party payors, willfully obstructing a criminal investigation of a health care offense, and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for health care benefits, items or services. Like the Anti-Kickback Statute, the ACA amended the intent standard for certain health care fraud statutes under HIPAA such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

Also, many states have similar fraud and abuse statutes or regulations that apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Additionally, to the extent that our product is sold in a foreign country, we may be subject to similar foreign laws.

We may be subject to data privacy and security regulations by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act (“HITECH”), and its implementing regulations, imposes requirements relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly applicable to business associates, independent contractors or agents of covered entities that receive or obtain protected health information in connection with providing a service on behalf of a covered entity. HITECH also created four new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce HIPAA and seek attorneys’ fees and costs associated with pursuing federal civil actions. In addition, many state laws govern the privacy and security of health information in specified circumstances, many of which differ from each other in significant ways and may not have the same effect, thus complicating compliance efforts.

Additionally, the federal Physician Payments Sunshine Act within the ACA, and its implementing regulations, require that certain manufacturers of drugs, devices, biological and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) report annually to CMS information related to certain payments or other transfers of value made or distributed to physicians and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians and their immediate family members. Moreover, the Drug Supply Chain Security Act imposes new obligations on manufacturers of pharmaceutical products related to product tracking and tracing. Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products.

In order to distribute products commercially, we must comply with state laws that require the registration of manufacturers and wholesale distributors of drug and biological products in a state, including, in certain states, manufacturers and distributors who ship products into the state even if such manufacturers or distributors have no place of business within the state. Some states also impose requirements on manufacturers and distributors to establish the pedigree of product in the chain of distribution, including some states that require manufacturers and others to adopt new technology capable of tracking and tracing product as it moves through the distribution chain. Several states have enacted legislation requiring pharmaceutical and biotechnology companies to establish marketing compliance programs, file periodic reports with the state, make periodic public disclosures on sales, marketing, pricing, clinical trials and other activities, and/or register their sales representatives, as well as to prohibit pharmacies and other health care entities from providing certain physician prescribing data to pharmaceutical and biotechnology companies for use in sales and marketing, and to prohibit certain other sales and marketing practices. All of our activities are potentially subject to federal and state consumer protection and unfair competition laws.

If our operations are found to be in violation of any of the federal and state health care laws described above or any other governmental regulations that apply to us, we may be subject to penalties, including without limitation, civil, criminal and/or administrative penalties, damages, fines, disgorgement, exclusion from participation in government programs, such as Medicare and Medicaid, injunctions, private “qui tam” actions brought by individual whistleblowers in the name of the government, or refusal to allow us to enter into government contracts, contractual damages, reputational harm, administrative

burdens, diminished profits and future earnings, and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

Coverage, pricing and reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we obtain regulatory approval. In the United States and markets in other countries, sales of any products for which we receive regulatory approval for commercial sale will depend, in part, on the extent to which third- party payors provide coverage, and establish adequate reimbursement levels for such products. In the United States, third-party payors include federal and state health care programs, private managed care providers, health insurers and other organizations. The process for determining whether a third-party payor will provide coverage for a product may be separate from the process for setting the price of a product or for establishing the reimbursement rate that such a payor will pay for the product. Third-party payors may limit coverage to specific products on an approved list, also known as a formulary, which might not include all of the FDA-approved products for a particular indication. Third-party payors are increasingly challenging the price, examining the medical necessity and reviewing the cost-effectiveness of medical products, therapies and services, in addition to questioning their safety and efficacy. We may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of our products, in addition to the costs required to obtain the FDA approvals. Our product candidates may not be considered medically necessary or cost-effective. A payor’s decision to provide coverage for a product does not imply that an adequate reimbursement rate will be approved. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product. Adequate third-party reimbursement may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development.

Different pricing and reimbursement schemes exist in other countries. In the EU, governments influence the price of pharmaceutical products through their pricing and reimbursement rules and control of national health care systems that fund a large part of the cost of those products to consumers. Some jurisdictions operate positive and negative list systems under which products may only be marketed once a reimbursement price has been agreed. To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost effectiveness of a particular product candidate to currently available therapies. Other member states allow companies to fix their own prices for medicines, but monitor and control company profits. The downward pressure on health care costs has become intense. As a result, increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross-border imports from low-priced markets exert a commercial pressure on pricing within a country.

The marketability of any product candidates for which we receive regulatory approval for commercial sale may suffer if the government and third-party payors fail to provide adequate coverage and reimbursement. In addition, emphasis on managed care in the United States has increased and we expect will continue to increase the pressure on health care pricing. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Healthcare reform

Healthcare reforms that have been adopted, and that may be adopted in the future, could result in further reductions in coverage and levels of reimbursement for pharmaceutical products, increases in rebates payable under U.S. government rebate programs and additional downward pressure on pharmaceutical product prices. Recently, healthcare reform initiatives culminated in the enactment of the Inflation Reduction Act (“IRA”), in August 2022, which will, among other things, allow the HHS to negotiate the selling price of certain drugs and biologics that CMS reimburses under Medicare Part B and Part D, although only high-expenditure single-source drugs that have been approved for at least 7 years (11 years for biologics) can be selected by CMS for negotiation, with the negotiated price taking effect two years after the selection year. The negotiated prices, which will first become effective in 2026, will be capped at a statutory ceiling price. Beginning in January 2023 for Medicare Part B and October 2022 for Medicare Part D, the IRA will also penalize drug manufacturers that increase prices of Medicare Part B and Part D drugs at a rate greater than the rate of inflation. The IRA permits the Secretary of HHS to implement many of these provisions through guidance, as opposed to regulation, for the initial years. Manufacturers that fail to comply with the IRA may be subject to various penalties, including civil monetary penalties. The IRA also extends enhanced

subsidies for individuals purchasing health insurance coverage in ACA marketplaces through plan year 2025. These provisions will take effect progressively starting in 2023, although they may be subject to legal challenges.

The Foreign Corrupt Practices Act

The Foreign Corrupt Practices Act(“FCPA”), prohibits any U.S. individual or business from paying, offering, or authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to comply with accounting provisions requiring us to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

Additional regulation

In addition to the foregoing, we are also subject to numerous federal, state and local laws relating to such matters as safe working conditions, manufacturing practices, environmental protection, fire hazard control, and disposal of hazardous or potentially hazardous substances, including the Occupational Safety and Health Act, the Resource Conservancy and Recovery Act and the Toxic Substances Control Act. These and other laws govern our use, handling and disposal of various biological, chemical and radioactive substances used in, and wastes generated by, our operations. If our operations result in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued compliance therewith will not have a material adverse effect on our business. We cannot predict, however, how changes in these laws may affect our future operations.

Europe / rest of world government regulation

In addition to regulations in the United States, we will be subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products. Whether or not we obtain FDA approval of a product, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the submission of a clinical trial application much like the IND prior to the commencement of human clinical trials. In the United Kingdom (“UK”) and countries in the EU, for example, a Clinical Trial Authorisation (“CTA”) must be submitted to each country’s national health authority and an independent ethics committee, much like the FDA and IRB, respectively. Once the CTA is approved in accordance with a country’s requirements, clinical trial development may proceed. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries. The requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, the clinical trials are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

To obtain regulatory approval of an investigational drug or biological product under EU and UK regulatory systems, we must submit a marketing authorization application. The application used to file the BLA in the United States is similar to that required in the EU and the UK, with the exception of, among other things, country-specific document requirements. For other countries outside of the EU and the UK, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical trials are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

If we or our potential collaborators fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

Australia

Conducting clinical trials for therapeutic drug candidates in Australia is subject to regulation by Australian governmental entities. Approval for inclusion in the Australian Register of Therapeutic Goods (the “ARTG”), is required before a pharmaceutical drug product may be marketed in Australia.

Typically, the process of obtaining approval of a new therapeutic drug product for inclusion in the ARTG requires compilation of clinical trial data. Clinical trials conducted using “unapproved therapeutic goods” in Australia, being those which have not yet been evaluated by the Therapeutic Goods Administration (the “TGA”), for quality, safety and efficacy must occur pursuant to either the Clinical Trial Notification (“CTN”), or Clinical Trial Exemption (“CTX”), process.

The CTN process broadly involves submission to a Human Research Ethics Committee (the “HREC”) of all material relating to the proposed clinical trial after completion of pre-clinical laboratory and animal testing. The institution or organization at which the clinical trial will be conducted (the “Approving Authority”) then gives the final approval for the conduct of the clinical trial at the site, having due regard to the advice from the HREC. After receiving final approval, CTN clinical trials cannot commence until the clinical trial has been notified to the TGA. Following approval, responsibility for all aspects of the trial conducted under a CTN application remains with the HREC of each investigator’s institution.

Under the CTX process a sponsor submits an application to conduct a clinical trial to the TGA for evaluation and comment and a sponsor cannot commence a CTX clinical trial until written advice has been received from the TGA regarding the application and approval for the conduct of the clinical trial has been obtained from an ethics committee and the institution at which the clinical trial will be conducted.

In each of the CTN or CTX process, it is required that adequate and well-controlled clinical trials demonstrate the quality, safety and efficacy of the therapeutic product, evidence is compiled which demonstrates that the manufacture of the therapeutic drug product complies with the principles of cGMP and manufacturing and clinical data is derived to submit to the Australian Committee on Prescription Medicines. The Australian Committee on Prescription Medicines then makes recommendations to the TGA and the TGA ultimately decides whether to include the therapeutic drug product in the ARTG.

The TGA has developed guidelines for a CTN. Under the CTN process, all material relating to the proposed clinical trial is submitted directly to the HREC of each institution at which the clinical trial is to be conducted. An HREC is an independent review committee set up under guidelines of the Australian National Health and Medical Research Council. The role of an HREC is to ensure the protection of rights, safety and wellbeing of human subjects involved in a clinical trial by, among other things, reviewing, approving and providing continuing review of trial protocols and amendments, and of the methods and material to be used in obtaining and documenting informed consent of the trial subjects. The TGA is formally notified by submission of a CTN application but does not review the safety of the drug or any aspect of the proposed trial.

The standards for clinical research in Australia are set by the TGA and the National Health and Medical Research Council, and compliance with GCP is mandatory. Guidelines, such as those promulgated by the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (“ICH”), are required across all fields, including those related to pharmaceutical quality, nonclinical and clinical data requirements and study designs. The basic requirements for preclinical data to support a first-in- human study under ICH guidelines are applicable in Australia. Requirements related to adverse event reporting in Australia are similar to those required in other major jurisdictions.

Employees and Human Capital Resources

As of December 31, 2022, we had 96 full-time employees. Of these employees, 65 were primarily engaged in research and development activities and 23 held a doctorate degree such as an M.D., Ph.D., or PharmD. None of our employees are represented by a labor union or covered by collective bargaining agreements. We have never experienced a work stoppage and believe that we have good employee relations.

We view our diverse employee population and our culture as key to our success. Our company culture prioritizes learning, supports growth and empowers us to reach new heights. We recruit employees with the skills and training relevant to succeed and thrive in their functional responsibilities. We assess the likelihood that a particular candidate will contribute to the Company’s overall goals, and beyond their specifically assigned tasks. Depending on the position, our recruitment reach can be local as well as national. We provide competitive compensation and benefits that are tailored specifically to the needs and requests of our employees.

Corporate Information

We were incorporated under the laws of the State of Delaware in November 2005. Our principal executive offices are located at 10770 Wateridge Circle, Suite 210, 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 report.

Available Information

We file Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other information with the Securities and Exchange Commission (“SEC”). Our filings with the SEC are available free of charge on the SEC’s website at www.sec.gov and on our website under the “Investors” tab as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC.

Item 1A. Risk Factors

Investing in our common stock involves a high degree of risk. You should carefully consider the risks described below, as well as the other information in this report, including our consolidated financial statements and the related notes and “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” before deciding whether to invest in our common stock. The occurrence of any of the events or developments described below could harm our business, financial condition, results of operations, and growth prospects. In such an event, the market price of our common stock could decline, and you may lose all or part of your investment.

Summary of Risk Factors

An investment in our common stock involves various risks, and prospective investors are urged to carefully consider the matters discussed in the section titled “Risk Factors” prior to making an investment in our common stock. These risks include, but are not limited to, 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. Results from our initial clinical trials may not be representative of the results we will experience in later clinical trials. 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 product candidates when dosed in humans. Our ongoing and planned clinical trials or those of our collaborators may reveal significant adverse events, toxicities or other side effects and may result in a 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 expand our pipeline of product candidates and develop marketable products.

•We have recently commenced clinical development of rosnilimab and ANB032, and have no history of 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 product candidates may not achieve adequate market acceptance among physicians, patients, health care payors and others in the medical community necessary for commercial success.

•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, our ability to obtain marketing approval, or our ability to provide supply of our products for patients, if approved, could be delayed or stopped.

•Political, economic or public health events, such as the COVID-19 pandemic, may have a material impact on the U.S. and global economies and could have a material adverse impact on our employees, contractors and patients, which could adversely and materially impact our business, financial condition and results of operations.

•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 sales of our product candidates.

•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.

•We must attract and retain highly skilled employees in order to succeed.

•We currently have no marketing and sales force. If we are unable to establish effective sales or marketing capabilities or enter into agreements with third parties to sell or market our product candidates, we may not be able to effectively sell or market our product candidates, if approved, or generate product revenue.

•Our existing collaboration with GSK is important to our business, and future collaborations may also be important to us. If we are unable to maintain this collaboration, or if this collaboration is not successful, our business could be adversely affected.

•We may not succeed in establishing and maintaining additional development and commercialization collaborations, including the development or out-licensing of our legacy product candidates, which could adversely affect our ability to develop and commercialize product candidates.

•Even if our product candidates receive regulatory approval, they will be subject to significant post-marketing regulatory requirements.

•If we are unable to obtain or protect intellectual property rights, we may not be able to compete effectively in our market.

•We may not be able to protect our intellectual property rights throughout the world.

•The market price of our stock has been and may continue to be volatile, and you could lose all or part of your investment.

Risks Related to Discovery and Development of Our Product Candidates

Our product candidates are in early stages of development and may fail in development or suffer delays that adversely affect their commercial viability. Results from our initial clinical trials may not be representative of the results we will experience in later clinical trials. 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 are developing therapeutic antibodies, including our wholly-owned product candidates, as well as other programs that are being developed by our collaborators. However, all of our wholly-owned and most of partnered product candidates are in various stages of development, and, for a wide variety of reasons discussed below, may fail in development or suffer delays that adversely affect their commercial viability.

A product candidate can unexpectedly fail at any stage of preclinical and clinical development. The historical failure rate for product candidates is high due to scientific feasibility, safety, efficacy, changing standards of medical care, and other variables. The results from preclinical testing or early clinical trials of a product candidate may not predict the results that will be obtained in later phase clinical trials of the product candidate. For example, results from our initial Phase 2a clinical trial of etokimab in moderate-to-severe atopic dermatitis patients were not representative of the results we experienced in our later etokimab moderate-to-severe atopic dermatitis Phase 2b clinical trial called “ATLAS” and we ultimately discontinued development of etokimab.

Furthermore, we may conduct clinical trials of a product candidate in multiple indications based on assumptions about the product candidate’s mechanism of action. However, it is possible that our assumptions regarding the effectiveness of a product candidate’s mechanism of action may be incorrect and that the product candidate may be ineffective in certain diseases or disorders. If this were the case, then the results from any clinical trials of a product candidate that we conduct are less likely to be positive. For example, we believed imsidolimab’s mechanism of action, the inhibition of IL-36R, provided the potential for imsidolimab to be effective for treatment of a range of dermatological inflammatory diseases. However, top-line data from clinical trials of imsidolimab in indications other than GPP did not demonstrate efficacy, and we do not currently plan to conduct further development of imsidolimab in indications other than GPP.

If our other ongoing or future clinical trials of any of our product candidates, including rosnilimab, ANB032, imsidolimab or ANB033, are unsuccessful, whether for one of the reasons mentioned above or otherwise, our product candidates may be delayed in development or fail entirely, which would have a material adverse impact on our business.

The success of our current product candidates, and any other product candidates we may develop in the future, will depend on many factors, including the following:

•obtaining regulatory permission to initiate clinical trials;

•successful enrollment of patients in, and the completion of, our planned clinical trials;

•receiving marketing approvals from applicable regulatory authorities;

•establishing commercial manufacturing capabilities and/or making arrangements with third-party manufacturers;

•obtaining and maintaining patent and trade secret protection and non-patent exclusivity for our product candidates and their components;

•enforcing and defending intellectual property rights and claims;

•achieving desirable therapeutic properties for our product candidates’ intended indications;

•launching commercial sales of our product candidates, if and when approved, whether alone or in collaboration with third parties;

•acceptance of our product candidates, if and when approved, by patients, the medical community and third-party payors;

•effectively competing with other therapies; and

•maintaining an acceptable safety profile of our product candidates through clinical trials and following regulatory approval.

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to successfully commercialize our product candidates, which would harm our business.

Furthermore, delays or difficulties in patient enrollment or difficulties in retaining trial participants can result in increased costs, longer development times, or termination of a clinical trial. Clinical trials of a new product candidate require the enrollment of a sufficient number of patients, including patients who are suffering from the disease the product candidate is intended to treat and who meet other eligibility criteria. Rates of patient enrollment are affected by many factors, including the size of the patient population, the eligibility criteria for the clinical trial, the age and condition of the patients, the stage and severity of disease, the nature of the protocol, the proximity of patients to clinical sites, and the availability of effective treatments for the relevant disease. We may not be able to initiate our planned clinical trials if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA or foreign regulatory authorities. More specifically, some of our product candidates, including imsidolimab, initially target indications that are very rare, which can prolong the clinical trial timeline for the regulatory process if sufficient patients cannot be enrolled in a timely manner.

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

In order to obtain marketing approval for any of our product candidates, we must demonstrate the safety and efficacy of the product candidate for the relevant clinical indication or indications through preclinical studies and clinical trials as well as additional supporting data. If our product candidates are associated with undesirable side effects in preclinical studies or clinical trials or have characteristics that are unexpected, we may need to interrupt, delay or abandon their development or limit development to more narrow uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective.

We have conducted various preclinical studies of our product candidates, but we do not know the predictive value of these studies for humans, and we cannot guarantee that any positive results in preclinical studies will successfully translate to human patients. Phase 2 and Phase 3 clinical trials with rosnilimab, ANB032 and imsidolimab are ongoing or planned. It is not uncommon to observe results in human clinical trials that are unexpected based on preclinical testing, or to observe results in later stage clinical trials that are unexpected based on early clinical trials. Many product candidates fail in clinical trials despite promising preclinical and early clinical results. In addition, top-line results of a clinical trial, which generally reflect preliminary reviews of primary efficacy and/or safety results, do not necessarily predict final results, and any top-line findings or assessments are subject to change pending the completion of final data review procedures. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval for their products.

Some patients in our clinical trials have experienced adverse events, including serious adverse events. We reported that one patient dropped out of the GALLOP Phase 2 clinical trial for imsidolimab due to diagnosis with Staphylococcal aureus bacteremia on Day 3 post-imsidolimab administration, which was a serious adverse event deemed to be possibly drug-related. Subjects in our ongoing and planned clinical trials may in the future suffer significant adverse events or other side effects not observed in our preclinical studies or in our Phase 1 or Phase 2 clinical trials. The observed potency and kinetics of our product candidates in preclinical studies may not be observed in human clinical trials. We have tested the dosing frequency and route of administration of our product candidates in preclinical studies, which will inform our dosing strategy for future clinical trials, however such dose and route of administration may not result in sufficient exposure or pharmacological effect in humans and may lead to unforeseen toxicity not previously observed in preclinical testing. If preclinical studies of our product candidates fail to provide preliminary evidence of safety to the satisfaction of regulatory authorities or do not otherwise produce satisfactory results, we may incur additional costs or experience delays in initiating and/or advancing the development and commercialization of our product candidates. Further, if clinical trials of our product candidates fail to demonstrate safety and

efficacy to the satisfaction of regulatory authorities or do not otherwise produce positive results, we or our collaborators may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our product candidates.

If further significant adverse events or other side effects are observed in any of our current or future clinical trials, we may have difficulty recruiting patients to the clinical trial, patients may drop out of our trial, or we may be required to abandon the trial or our development efforts of that product candidate altogether. We, the FDA, or other applicable regulatory authorities, or an institutional review board or ethics committee, may suspend clinical trials of a product candidate at any time for various reasons, including a belief that subjects in such clinical trials are being exposed to unacceptable health risks or adverse side effects. Some potential therapeutics developed in the biotechnology industry that initially showed therapeutic promise in early-stage studies have later been found to cause side effects that prevented their further development. Even if the side effects do not preclude a product candidate from obtaining or maintaining marketing approval, undesirable side effects may inhibit market acceptance of the approved product due to its tolerability versus other therapies. Any of these developments could materially harm our business, financial condition and prospects.

Further, if any of our product candidates obtain marketing approval, toxicities associated with our product candidates may also develop after such approval and lead to a requirement to conduct additional clinical safety trials, additional warnings being added to the labeling, significant restrictions on the use of the product or the withdrawal of the product from the market. We cannot predict whether our product candidates will cause toxicities in humans that would preclude or lead to the revocation of regulatory approval based on preclinical studies or early stage clinical testing.

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.

Our ability to continue to develop our product candidates, and to have the potential to achieve and sustain profitability, depends on the FDA and foreign regulatory authorities permitting us to conduct human clinical trials and, if our product candidates are safe and effective, obtaining approval from the FDA and foreign regulatory authorities to market them and subsequently successfully commercializing them, either alone or with our collaborators. The research, testing, manufacturing, labeling, approval, selling, marketing and distribution of drug and biologic products are subject to extensive regulation by the FDA and foreign regulatory authorities. Before commencing clinical trials in the United States for any other product candidate, we must submit an IND to the FDA; foreign regulatory authorities enforce similar requirements for initiation of clinical trials in other countries. An IND or foreign equivalent requires extensive preclinical studies, and there is no guarantee that the FDA or foreign regulatory authorities will allow clinical trials to proceed based on the IND or equivalent submission. For example, although we have initiated toxicology studies for our product candidates, the FDA in the United States, or other foreign regulatory authorities, as applicable, may not allow our clinical trials to proceed in the regulatory authority’s jurisdiction if we are unable to show safety margins acceptable to the particular regulatory authority in appropriate animal species in our preclinical toxicology studies.

Even if we or our collaborators initiate and complete clinical trials for our product candidates, these product candidates will not be permitted to be marketed in the United States until approval of a BLA from the FDA is received, and will not be permitted to be marketed in other countries without marketing approval from foreign regulatory authorities. Obtaining approval of a BLA or other marketing approvals is often a lengthy, expensive and uncertain process over which the FDA and foreign regulatory authorities have substantial discretion. Other than submitting and receiving acceptance for initiation of our previous and current clinical trials in the United States and certain foreign jurisdictions, we have had only limited discussions with the FDA and no discussions with foreign regulatory authorities regarding the development plans for any of our product candidates or the designs of any of our later-stage clinical studies. We thus may not have the full benefit of the FDA’s or foreign regulatory authorities’ current thinking on clinical trial designs or product development for our target indications. For example, we believe our planned Phase 3 trials for imsidolimab for GPP, GEMINI-1 and GEMINI-2, with GEMINI-1 enrolling approximately 45 moderate-to-severe GPP patients, will be sufficient to demonstrate substantial evidence of efficacy and safety of imsidolimab in GPP patients and obtain BLA approval, and we discussed these plans with the FDA in an end-of-Phase 2 meeting, during the second quarter of 2021. However, the FDA may determine, based on future clinical efficacy and safety data from our GPP studies, that we will need additional clinical trials in order to obtain approval of a BLA.

Preclinical studies and clinical trials are expensive, difficult to design and implement, can take many years to complete, and are uncertain as to outcome. Product candidates, on average, take 10 to 15 years to be developed from the time they are discovered to the time they are approved and available for treating patients. The start or end of a clinical trial is often delayed or halted for many reasons, including:

•imposition of a clinical hold for safety reasons or following an inspection of clinical trial operations or site by the FDA or other regulatory authorities;

•manufacturing challenges;

•insufficient supply or quality of product candidates or other materials necessary to conduct clinical trials;

•delays in reaching or failure to reach agreement on acceptable clinical trial contracts or clinical trial protocols with prospective trial sites and CROs or failure by such CROs or trials sites to carry out the clinical trial in accordance with our agreed-upon terms;

•non-clinical or clinical sites becoming unavailable due to political, economic, or public health events, such as the COVID-19 pandemic;

•clinical sites electing to terminate their participation in one of our clinical trials;

•inability or unwillingness of patients or medical investigators to follow clinical trial protocols;

•required clinical trial administrative actions;

•slower than anticipated patient enrollment;

•changing standards of care;

•safety concerns;

•availability or prevalence of use of a comparative drug or required prior therapy; or

•clinical outcomes or financial constraints.

Our product candidates may not be effective, may be only moderately effective, or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing approval or prevent or limit commercial use. Regulatory authorities may refuse to accept any application or may decide that our data are insufficient for approval and require additional preclinical or other studies or clinical trials. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate. Moreover, regulatory authorities may determine that the clinical and other benefits of a product candidate do not outweigh the safety or other risks. Changes in marketing approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted product application may also cause delays in or prevent the approval of an application.

If we or our collaborators experience any of the issues described above, or other similar or related issues, we or our collaborators may:

•be delayed in obtaining marketing approval for our product candidates;

•not obtain marketing approval at all;

•obtain marketing approval in some countries and not in others;

•obtain approval for indications or patient populations that are not as broad as intended or desired;

•obtain approval with labeling that includes significant use or distribution restrictions or safety warnings, including boxed warnings;

•be subject to additional post-marketing testing requirements; or

•have the product removed from the market after obtaining marketing approval.

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

Because we have limited financial and managerial resources, we focus on research programs and product candidates that we identify for specific indications. Our business depends on our successful development and commercialization of the limited number of internal product candidates we have in preclinical and early-stage clinical development. Even if we are successful in continuing to build our pipeline, development of the potential product candidates that we identify will require substantial investment in additional clinical development, management of clinical, preclinical and manufacturing activities, regulatory approval in multiple jurisdictions, building a commercial organization, and significant marketing efforts before we generate any revenue from product sales. Furthermore, such product candidates may not be suitable for clinical development, including as a result of their harmful side effects, limited efficacy or other characteristics that indicate that they are unlikely to be products that will receive marketing approval and achieve market acceptance. If we cannot successfully develop, partner and/or commercialize product candidates, we may not be able to obtain product or partnership revenue in future periods, which would adversely affect our business, prospects, financial condition and results of operations.

As a result of our current focus on our lead product candidates, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs and product candidates for specific indications may not yield any commercially viable products. Our understanding and evaluation of biological targets for the discovery and development of new product candidates may fail to identify challenges encountered in subsequent preclinical and clinical development. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights.

We have recently commenced clinical development of rosnilimab and ANB032, and have no history of commercializing biotechnology products, which may make it difficult to evaluate the prospects for our future viability.

Our operations to date have been largely limited to financing and staffing our company, developing our technology, and developing our wholly-owned product candidates and other product candidates in partnerships with our collaborators. As a company, we have only very limited experience conducting pivotal Phase 3 clinical trials and have not had previous experience commercializing product candidates, including submitting a BLA to the FDA. In part because of this lack of experience, we cannot be certain that planned clinical trials will begin or be completed on time, if at all, that our planned development programs would be acceptable to the FDA or other regulatory authorities, or that, if approval is obtained, such product candidates can be successfully commercialized. Clinical trials and commercializing our wholly-owned product candidates will require significant additional financial and management resources, and reliance on third-party clinical investigators, CROs, consultants or collaborators. Relying on third-party clinical investigators, CROs or collaborators may result in delays that are outside of our control.

Furthermore, we may not have the financial resources to continue development of, or to enter into collaborations for, a product candidate if we experience any problems or other unforeseen events that delay or prevent regulatory approval of, or our ability to commercialize, product candidates, including:

•negative or inconclusive results from our clinical trials or the clinical trials of others for product candidates similar to ours, leading to a decision or requirement to conduct additional preclinical testing or clinical trials or abandon a program;

•delays in submitting INDs or comparable foreign applications or delays or failure in obtaining the necessary approvals from regulators to commence a clinical trial, or a suspension or termination of a clinical trial once commenced;

•conditions imposed by the FDA or foreign regulatory authorities regarding the number, scope or design of our clinical trials;

•delays in enrolling research subjects in clinical trials;

•high drop-out rates of research subjects;

•inadequate supply or quality of clinical trial materials or other supplies necessary for the conduct of our clinical trials;

•greater than anticipated clinical trial costs;

•poor effectiveness or unacceptable side effects of our product candidates during clinical trials;

•unfavorable FDA or other regulatory agency inspection and review of a clinical trial site;

•failure of our third-party contractors or investigators to comply with regulatory requirements or otherwise meet their contractual obligations in a timely manner, or at all;

•serious and unexpected drug-related side effects experienced by participants in our planned clinical trials or by individuals using drugs similar to our product candidates;

•delays and changes in regulatory requirements, policy and guidelines, including the imposition of additional regulatory oversight around clinical testing generally or with respect to our technology in particular; or

•varying interpretations of data by the FDA and foreign regulatory authorities.

Consequently, any predictions you make about our future success or viability based on our short operating history may not be as accurate as they could be if we had a longer operating history or an established track record in conducting clinical trials or commercializing products.

Further, as a clinical stage business, we may encounter unforeseen expenses, difficulties, complications, delays, and other known and unknown factors. We will need to transition from a company with a research focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

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.

ANAB US Equity

ANAB · 10-K · period ended 2022-12-31

Item 1. Business

Item 1A. Risk Factors

ANAB US Equity☆

ANAB · 10-K · period ended 2022-12-31

Item 1. Business

Item 1A. Risk Factors

ANAB US Equity