ANAPTYSBIO, INC (ANAB) Business

Item 1. Business

Overview

We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics for autoimmune and inflammatory diseases. Our clinical-stage pipeline includes rosnilimab, a selective pathogenic T cell depleter, for which we completed a Phase 2b trial for the treatment of moderate-to-severe rheumatoid arthritis (“RA”), ANB033, a CD122 antagonist, in a Phase 1b trial for celiac disease (“CeD”) and eosinophilic esophagitis (“EoE”), and ANB101, a BDCA2 modulator, in a Phase 1a trial. We also discovered and out-licensed, in financial collaborations, multiple therapeutic antibodies, including a PD-1 antagonist (Jemperli (dostarlimab-gxly) or “Jemperli”) to GSK and an IL-36R antagonist (imsidolimab) to Vanda Pharmaceuticals Inc. (“Vanda”). We currently recognize revenue from milestones and royalties achieved under our immuno-oncology collaboration with GSK and license and transition services revenue from our collaboration with Vanda.

Intention to Separate Company

In September 2025, we announced that our board of directors (“Board of Directors”) approved plans to explore separating our business into two independent, publicly traded companies. One company is expected to hold and continue to manage the financial collaboration for Jemperli from GSK and for imsidolimab from Vanda, with a focus on protecting and returning value of the royalties to its shareholders. The other company is expected to be a clinical-stage biotechnology company focused on the development and potential commercialization of innovative therapeutics for autoimmune and inflammatory diseases, including rosnilimab, ANB033 and ANB101. Upon completion of the proposed separation, which we expect to complete in the second quarter of 2026, we intend to launch the clinical-stage biotechnology company with adequate capital to fund operations for at least twelve months after the date the proposed separation is completed. While the proposed separation is anticipated to be a taxable event, we are focused on minimizing overall corporate and shareholder-level taxes across the entire transaction. Completion of the proposed separation is subject to final approval by our Board of Directors and other customary conditions, including the effectiveness of a registration statement with the Securities and Exchange Commission (the “SEC”).

Our Wholly Owned Clinical-Stage Pipeline

Our antibodies are in development to treat inflammatory diseases. We believe these molecules have potential applicability across a broad range of autoimmune and inflammatory diseases, including in gastroenterology, rheumatology, dermatology, respiratory, and other therapeutic areas.

Rosnilimab

Rosnilimab is an IgG1 antibody that directly targets pathogenic T cells, such as activated Tph/Tfh and T effector cells, in the periphery or inflamed tissue. These T cells, when activated, proliferate and migrate, and secrete the inflammatory cytokines that are the drivers of autoimmune and inflammatory diseases. Rosnilimab is designed to selectively deplete pathogenic T cells in both inflamed tissue and the periphery while sparing non-pathogenic T cells, including naïve T cells, to preserve overall immune function and restore immune homeostasis. This drives specific immunological outcomes, such as a reduction in T cell proliferation, migration and cytokine secretion, and a reduction of plasma cell generation and autoantibody levels. We announced top-line data from a healthy volunteer Phase 1 trial of rosnilimab in November 2021 that supported advancement of rosnilimab into subsequent patient trials. 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 received subcutaneous (“SC”) or intravenous (“IV”) single 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. Rosnilimab demonstrated a sustained systemic exposure and dose-proportionality with an estimated two-week half-life for subcutaneous and IV routes of administration.

In February 2025, we announced initial data, which was subsequently updated in June 2025, from rosnilimab’s randomized, placebo-controlled, global 424-patient, Phase 2b clinical trial for moderate-to-severe rheumatoid arthritis. Patients were randomized to receive either 100mg of subcutaneous rosnilimab every four weeks (Q4W), 400mg Q4W, 600mg every two weeks, or placebo.

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During the three-month placebo-controlled period, the trial achieved its primary endpoint by observing the reduction of disease activity using the disease activity score, 28 joints (DAS-28) C-Reactive Protein (“CRP”) score, as well as ACR20 response (an accepted Phase 3 registrational endpoint), at Week 12 in all three doses of rosnilimab compared to placebo. Rosnilimab achieved its secondary endpoint by demonstrating statistical significance in at least one dose and numerical superiority at all doses, including once monthly administration, on ACR20, ACR50 and with respect to the clinical disease activity index (“CDAI”) low disease activity (“LDA”) score at Week 12. Specifically, at Week 12, ACR20 achieved statistical significance at 100 mg (p 0.05), 400 mg (p 0.01), and 600 mg (p 0.001); ACR50 achieved statistical significance at 600 mg (p 0.05); and CDAI LDA achieved statistical significance at 100 mg (p 0.05) and 400 mg (p 0.01).

Following completion of the Week 14 visit, 69% (or 220 of the 318) rosnilimab-treated patients who achieved CDAI LDA at this timepoint continued their assigned treatment through six months in a blinded, all-active treatment period. At six months, rosnilimab results demonstrated deepening of responses through six months on CDAI LDA, CDAI remission and ACR70 and independent of prior treatments, including anti-TNFα, anti-IL6R or JAK inhibitors. Importantly, this was particularly observed in b/tsDMARD-experienced patients for the 400mg Q4W and 600mg Q2W doses, showing a dose response relative to the 100mg Q4W dose. Furthermore, Week 28 clinical responses across multiple measures, including CDAI LDA, mean CDAI, mean DAS28-CRP and ACR50/70, were durable off-drug through at least three months after the last rosnilimab dose, results which we believe suggest the potential for extended dosing (e.g., Q8W/Q12W) after initial monthly dosing. Due to the trial design, max response rates for rosnilimab have not yet been observed as strict criteria at Week 14, which prevented additional patients with meaningful improvement from continuing treatment in the trial.

A table summarizing the results for primary and secondary endpoints follows:

*p0.05

**p0.01

***p0.001

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Clinical outcomes were further substantiated by objective translational data. An approximately 50% reduction in the mean CRP from baseline, an objective measure of inflammation, was observed through Week 28 in rosnilimab patients who entered the all-active period. Additionally, translational blood and synovial biopsy biomarker data showed differentiated and consistent immunological impact with on-target pharmacological activity in rosnilimab patients that was not observed on placebo. In blood, rosnilimab demonstrated rapid, deep and sustained reductions of approximately 90% in pathogenic T cells (largely Tph, Tph and Teff cells), and an increase in total Tregs. Additionally, synovial biopsies of the most impacted joint taken at baseline and after six weeks showed a deep reduction of approximately 90% in pathogenic T cells (largely Tph cells) at the 400mg Q4W and 600mg Q2W doses, showing a dose response relative to the 100mg Q4W dose.

Consistent with prior rosnilimab studies, all rosnilimab doses through end-of-trial follow up at week 38 demonstrated no treatment-related serious adverse events (“SAEs”), malignancies, anaphylaxis or systemic hypersensitivity, and a low incidence of injection site reactions. Most adverse events (“AEs”) were mild to moderate in severity. Less than 2% of patients in the trial discontinued rosnilimab due to an AE, including only one patient after three months for a moderate headache treated with over-the-counter pain medication. Non-treatment related SAEs observed were consistent with known RA patient history and comorbidities.

ANB033

ANB033 is an antagonist of CD122, the common beta subunit shared by the IL-15 and IL-2 receptors. IL-15 and IL-2 signaling mediate the proliferation and survival of subsets of CD8+ and CD4 T+ cells, NK cells, as well as ILC2s. ANB033 is an antibody designed with an optimal epitope and affinity to CD122 that inhibits IL-15 and IL-2 signaling through both the intermediate affinity IL-2 receptor (comprised of CD122 and the common gamma subunit, CD132) and the high affinity IL-2 receptor (comprised of CD122, CD132 and the alpha receptor subunit for IL-2, CD25) expressed by activated CD4 Th1 and Th2 T cells as well as ILC2. Antagonizing CD122 has the potential to achieve and maintain remission of inflammation through the reduction of disease-causing cytolytic CD8 T cell subsets, including intraepithelial lymphocytes, NK cells and reducing inflammatory cytokine secretion by activated CD4+ Th1 and Th2 cells, as well as ILC2 cells.

We announced top-line data from a healthy volunteer Phase 1a trial of ANB033 in October 2025 that demonstrated no safety concerns at any dose and a rapid and sustained pharmacokinetic (“PK”) profile. A total of 80 subjects were enrolled in the randomized, double-blind, placebo-controlled healthy volunteer Phase 1 trial, where SAD cohorts received SC or IV single doses of ANB033 or placebo, while MAD cohorts received four weekly SC doses of ANB033. ANB033 was generally well-tolerated and no SAE discontinuations or dose-limiting toxicities were observed in the study. ANB033 demonstrated an estimated two-to-three week half-life and full receptor occupancy for SC and IV routes of administration. A dose response was observed on relevant PD biomarkers. We observed responsive effects with both IV and SC modes of administration, with a 70-75% reduction in CD122-expressing CD8 T cells, which did not result in a meaningful reduction in overall CD8 T cells. Additionally, treatment with ANB033 effectively eliminated all CD122-expressing NK cells, but the overall NK cell count remained above the levels needed to maintain immune competency as not all NK cells in humans express CD122. No overall reductions were observed on regulatory T cell counts in the peripheral blood.

We are conducting a randomized placebo-controlled 60-patient, global Phase 1b trial cohort of ANB033 in CeD. This trial will assess both a cohort of patients with baseline villus height to crypt depth (“Vh:Cd”) ratio greater than 2.0 in a gluten-challenge to assess prevention of further mucosal damage, as well as a cohort of patients with a Vh:Cd ratio less than 2.0, who will not be subjected to a gluten-challenge, to assess the ability to heal mucosal damage in symptom-controlled patients. The two distinct cohorts will enroll 30 patients each, randomized 1:1 between one dose level of subcutaneously administered ANB033 dose and placebo. Key assessments include safety and tolerability, efficacy assessments including the change in Vh:Cd ratio, IEL counts, and PROs, such as the Celiac Disease Symptom Diary (“CDSD”), as well as PK and immunogenicity.

We are also conducting a randomized placebo-controlled 50-patient, global Phase 1b trial cohort of ANB033 in EoE. This trial will enroll adults who have histologic evidence of EoE with peak eosinophil count ≥15/hpf at the screening endoscopy and with symptomatic dysphagia. Key assessments include safety and tolerability, efficacy assessments including the Dysphagia Symptom Questionnaire (“DSQ”) and peak esophageal intraepithelial eosinophilic count (“eos/hpf”), as well as PK and immunogenicity.

ANB101

ANB101 is a blood dendritic cell antigen 2 (“BDCA2”) modulator antibody that targets plasmacytoid dendritic cells (“pDCs”) and inhibits interferon secretion and modulates antigen presentation for the treatment of autoimmune and inflammatory diseases.

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BDCA2 is a molecule specifically expressed on pDCs, a class of immune cells which, while found in relatively small numbers in healthy individuals, are enriched in patients with a variety of inflammatory diseases, that is critical to the regulation of toll-like receptor signaling and interferon secretion. pDCs are a key upstream node in the inflammatory cascade that serve as a bridge between innate and adaptive immunity. They have been shown to be prolific secretors of type I interferons, which drive activation of a variety of downstream cell types including T cells and monocytes. Together with their ability to present antigens to the adaptive immune system, this creates a pro-inflammatory environment for the establishment and perpetuation of autoimmune pathology. BDCA2 has been implicated in the pathophysiology of systemic lupus erythematosus (“SLE”), where there exists mechanistic clinical proof of concept for pDC modulation.

We initiated a Phase 1 clinical trial of ANB101 in healthy volunteers in March 2025 and the trial is ongoing. ANB101 preclinical data suggests it is a more potent antibody compared to litifilimab with a longer half-life that results in a deeper and more durable PD effect on pDC depletion.

Collaborative Programs

GSK Collaboration

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 a 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). In July 2023, the FDA approved Jemperli in combination with chemotherapy for the treatment of adult patients with dMMR MSI-H primary advanced or recurrent endometrial cancer. In December 2023, the EMA approved Jemperli plus chemotherapy for dMMR/MSI-H primary advanced or recurrent endometrial cancer. In August 2024, the FDA approved Jemperli plus chemotherapy for all adult patients with primary advanced or recurrent endometrial cancer. In January 2025, the EMA approved Jemperli plus chemotherapy for this same indication. In October 2025, GSK terminated the TIM-3 antagonist antibody development program under our existing collaboration, and all rights to the TIM-3 antagonist antibody will be reverted to us in the near future.

For the year ended December 31, 2025, GSK reported $1.1 billion in sales for Jemperli, a greater than 80% sales growth when compared to $598.0 million for the year ended December 31, 2024.

Vanda Collaboration

On January 31, 2025, we entered into an Exclusive License Agreement (the “Vanda License Agreement”) with Vanda pursuant to which we granted to Vanda an exclusive, global license for the development and commercialization of imsidolimab (IL-36R antagonist mAb), which has completed two registration-enabling global Phase 3 trials, GEMINI-1 and GEMINI-2, evaluating the safety and efficacy of imsidolimab in patients with generalized pustular psoriasis (“GPP”).

In December 2025, Vanda announced the submission of a BLA to the U.S. FDA for imsidolimab in GPP. The FDA accepted the BLA filing for imsidolimab in GPP in February 2026 with a target action date of December 12, 2026.

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Pursuant to the terms of the Vanda License Agreement, we received an upfront payment of $10.0 million and a $5.0 million payment for existing drug supply. We are also eligible to receive a 10% royalty on net sales, as well as the following milestones under the Vanda License Agreement:

For more information about these collaborations, see Note 4 — Collaborative Research and Development Agreements in the accompanying notes to the consolidated financial statements.

Our Product Candidates

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

(1)
We expect to provide an update on Phase 3 advancement in the first half of 2026.

Our Strategy

We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics. Our antibodies modulate key nodes governing the body’s regulation of autoimmunity and inflammation. Dysregulated immune responses may result in abnormal and pathological inflammation in diseases with large and substantially underserved patient populations in therapeutic areas including but not limited to gastroenterology, rheumatology, dermatology, and respiratory. The key elements of our strategy include:

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Enabling broad development of our autoimmunity and inflammation-focused portfolio.

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Generating translational and clinical data to characterize the mechanism and differentiation of our molecules from in-class competitors, other modalities in clinical development, and, relative to standard of care, to optimize development of our molecules to address diseases and treat patient subsets with unmet medical need.

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Innovating in clinical development and execution to efficiently and optimally achieve proof-of-concept and execute registrational studies in key global markets.

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Facilitating the global commercialization of our product candidates while retaining rights in key commercial markets to enable us to become a fully integrated development and commercial organization.

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Continuing to leverage our research expertise to identify, license and/or innovate on potentially best-in-class antibodies against high-value immunological targets.

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Maximizing return on equity through execution against a multi-year capital and operating plan, including to manage and return the potential value from our future royalty revenues from our GSK financial collaboration to shareholders.

As described in the section titled “Risk Factors” and elsewhere in this Annual 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:

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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.

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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.

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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.

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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 one gram quantities per course of therapy).

Our approach to antibody design focuses on discovering and optimizing therapeutic antibodies tailored to modulate immune function. We use a variety of technologies to optimize the Fab domain of an antibody in ways that we believe both create a therapeutic antibody with highly potent functional activity and mitigate potential manufacturing liabilities.

We also optimize the Fc domain of the antibody, when needed, to tailor it for specific activity such as reducing Fc receptor interactions or optimizing 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 recapitulate the conditions in which the antibody will need to have optimal activity in patients.

We believe that our approach to antibody design allows us to effectively tailor antibodies to achieve a unique therapeutic benefit.

Collaborations

GSK Collaboration

In March 2014, we entered into a Collaboration and Exclusive License Agreement (the “GSK Agreement”) with TESARO, Inc. (“Tesaro”), an oncology-focused biopharmaceutical company now a part of GSK (Tesaro and GSK are hereinafter referred to, collectively, as “GSK”). Currently, under the GSK Agreement, GSK is developing Jemperli (dostarlimab) as a monotherapy and in combination with additional therapies, for various solid tumor indications.

For each remaining development program under the GSK Agreement, we are eligible to receive milestone payments if certain preclinical and clinical trial events are achieved by GSK, if certain U.S. and European regulatory submissions and approvals in multiple indications are achieved, and upon the achievement of specified levels of annual worldwide net sales. We will also be eligible to receive tiered 4-8% royalties related to worldwide net sales of products developed under the collaboration. On October 23, 2020, Amendment No. 3 to the GSK Agreement (the “GSK Amendment No. 3”) was agreed to by both parties to permit GSK to conduct development and commercialization in combination with any third party molecules of Zejula, an oral, once-daily poly (ADP-ribose) polymerase (PARP) inhibitor (“Zejula”). Under GSK Amendment No.3, we were granted increased royalties upon sales of Jemperli, equal to 8% of Net Sales (as defined in the GSK Agreement) below $1.0 billion, 12% of Net Sales between $1.0 billion and $1.5 billion, 20% of Net Sales between $1.5 billion and $2.5 billion and 25% of Net Sales above $2.5 billion. Unless earlier terminated by either party upon specified circumstances, the GSK Agreement will terminate, with respect to each specific developed product, upon the later of the 12th anniversary of the first commercial sale of the product or the expiration of the last to expire of any patent.

In October 2021, we signed a royalty monetization agreement (“Jemperli Royalty Monetization Agreement”) with Sagard Healthcare Royalty Partners, LP (“Sagard”). Under the terms of the Jemperli Royalty Monetization Agreement, we received $250.0 million in exchange for royalties and milestones payable to us under our GSK collaboration on annual global net sales of Jemperli.

In May 2024, we entered into an amendment to the Jemperli Royalty Monetization Agreement, Amendment No. 1 (the “Jemperli Amendment”) under which we sold additional receivables to Sagard in exchange for $50.0 million. The Jemperli Amendment includes all Jemperli sales, including any product containing Jemperli, whether or not such product constitutes a combination product, and the threshold amounts of aggregate Jemperli royalties and milestones to be received by Sagard under the

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Jemperli Amendment is either $600.0 million if received by the end of March 31, 2031, or $675.0 million if received thereafter. Once either of these thresholds are met, the Jemperli Royalty Monetization Agreement and the Jemperli Amendment will expire, resulting in us regaining all subsequent Jemperli royalties and milestones. As of December 31, 2025, Sagard has accrued approximately $250.0 million in royalties and milestones. For more information, see Note 5 — Sale of Future Royalties in the accompanying notes to the consolidated financial statements.

The 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.

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 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 co-owned with GSK, patents licensed from Centessa Pharmaceuticals (UK) Ltd. (“Centessa”), and patents to certain antibody discovery technology consisted of approximately 96 issued patents and 120 pending patent applications as of December 31, 2025. The foregoing does not include certain patents and patent applications that are not material to our business and which we intend to let lapse.

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 are outlined below:

Rosnilimab

As of December 31, 2025, we owned 33 patents and pending 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/or other patent applications claiming priority thereto, and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued or that may issue from or claim priority to our pending applications could provide protection for aspects of this product candidate until June 2040.

ANB033

As of December 31, 2025, we owned 16 pending U.S. provisional patent application and one pending international (PCT) patent application directed to the antibody sequence of ANB033 and its variants, methods of use and related matters. We intend to prosecute these patent applications, file additional patent applications claiming priority to these patent applications, and pursue patent issuance, in key commercial markets where significant product sales may occur. Patents that may issue claiming priority to these patent applications could provide protection for aspects of this product candidate until September 2045.

ANB101

As of December 31, 2025, we owned rights to 17 pending patent applications in various countries directed to the antibody sequence of ANB101 and its variants, methods of use and related matters. We intend to prosecute the pending applications, and/or other patent applications claiming priority thereto, and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that may issue from or claim priority to the pending applications could provide protection for aspects of these product candidates until August 2040.

Dostarlimab (GSK4057190)

As of December 31, 2025, we owned or co-owned 26 patents and patent applications in various countries directed to the antibody sequence of GSK4057190 (dostarlimab), a PD-1 antagonist, and its variants, methods of use and related matters. We intend to prosecute our pending applications, and/or other patent applications claiming priority thereto, and pursue patent issuance and

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protection in key commercial markets where significant product sales may occur. Patents that have issued, or that may issue from or claim priority to our pending applications, could provide protection for aspects of this product until June 2038.

Imsidolimab

As of December 31, 2025, we owned 45 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/or other patent applications claiming priority thereto, and pursue patent issuance and protection in key commercial markets where significant product sales may occur. Patents that have issued, or that may issue from or claim priority to our pending applications could provide protection for aspects of this product candidate until May 2042.

License Agreement with Centessa

On November 24, 2023, we entered into an exclusive license agreement (as amended, the “Centessa Agreement”) with Centessa, pursuant to which we acquired the exclusive global development and commercialization rights to a blood dendritic cell antigen 2 (BDCA2) modulator antibody portfolio, including lead asset CBS004 (renamed ANB101) and the related family of antibodies, for the treatment of autoimmune and inflammatory diseases.

In connection with the Centessa Agreement, we paid Centessa an upfront cash payment of $4.0 million and an additional cash payment of $3.0 million as reimbursement to Centessa for manufacturing costs incurred. There were $0.3 million in transaction costs incurred. The total transaction amount of $7.3 million was expensed as in-process research and development and classified as an operating activity in the statement of cash flows. We accounted for the transaction as an asset acquisition as the set of acquired assets did not constitute a business.

Under the terms of the Centessa Agreement, Centessa may be entitled to receive potential future payments of up to $10.0 million upon the achievement of a certain event-based milestone and would be entitled to receive on a product-by-product and country-by-country basis, a royalty of low single digits on annual net sales of any product in the territory in each calendar year until, on a product-by-product and country-by-country basis, the latest of: (a) expiration of the last-to-expire licensed patent covering such product in such country, (b) expiration of regulatory exclusivity for such product in such country and (c) ten years after the first commercial sale of such product in such country. We have not recognized a liability for the associated $10.0 million contingent consideration because, as of December 31, 2025, achievement of the milestone is not probable in the near term.

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. 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

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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 research and development 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 our product candidates for clinical trial use in compliance with current good manufacturing practices (“cGMP”) regulations. The cGMP regulations include requirements relating to organization of personnel, buildings and facilities, equipment, control of materials, 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 global regulatory requirements before any product is approved and we can manufacture commercial products. Our third party manufacturers will be subject to periodic regulatory inspections of facilities by the FDA and other authorities, including procedures and operations used in the testing and manufacture of our products to assess 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 our product candidates for use in human clinical trials.

We rely on third party manufacturers to generate cGMP compliant cell lines and will rely on them to produce cGMP drug substance and 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 testing, labeling, packaging, storage and distribution of investigational drug products. We have personnel with significant technical, manufacturing, analytical, quality, including cGMP regulations, 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 regulations and have been previously inspected by regulatory authorities for compliance with cGMP standards.

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. Third party manufacturers often encounter difficulties involving production yields, quality control and quality assurance, as well as shortages of qualified personnel.

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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 rosnilimab, our competitors include non-depleting PD-1 agonist antibodies GS-0151, (Gilead) in Phase 1b development for the treatment of rheumatoid arthritis, and S-4321 (Seismic Therapeutics) in Phase 1 development. Our commercial-stage 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-CD122 antagonist antibody program, our clinical competitors include an anti-CD122 antagonist antibody, FB-102 (Forte Bioscience) in Phase 2a development for the treatment of CeD, Phase 1b development for the treatment of vitiligo, and Phase 1b development for the treatment of alopecia areata, and two anti-IL-15 monoclonal antibodies, GIA632 (Novartis) in Phase 2a development for atopic dermatitis and with proof-of-concept, Phase 1b data for the treatment of CeD and EoE, and TEV-53408 (Teva), in Phase 2 development for the treatment of CeD and vitiligo. To date, there are no FDA-approved therapies for the treatment of celiac disease and only one FDA-approved biologic, Dupixent, for the treatment of EoE.

For our anti-BDCA2 program, our competitors include another anti-BDCA2 antibody, litifilimab (Biogen) in Phase 3 development for SLE and CLE, and a bispecific fusion protein targeting BDCA2 and BAFF/APRIL, DNTH212 (Dianthus Therapeutics) in Phase 1 development, and an anti-ILT7 antibody, daxdilimab (Amgen) in Phase 2 development.

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.

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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.

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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 regulations 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:

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the investigator’s qualifications;

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a description of the research facilities;

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

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

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information showing that the study is adequate and well controlled;

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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;

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

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a description of how informed consent was obtained;

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

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

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

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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.

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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 from the date of marketing approval.

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 the drug covered by the patent for which a patent extension is being sought is likely to be approved. 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.

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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 cGMP regulations 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 cGMP regulations. Accordingly, manufacturers must continue to expend time, money, and effort in the areas of production and quality-control to maintain compliance with cGMP regulations. 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.

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 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 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.

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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.

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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. Further, reductions in health insurance and other healthcare funding as a result of the OBBBA may exacerbate the cost-consciousness of third-party payors and their willingness to provide coverage for newly developed products such as ours. As a result, 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. Healthcare reform initiatives include the enactment of the Inflation Reduction Act (“IRA”), which, among other things, allows 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 seven years (11 years for biologics) can be selected by CMS for negotiation, with the negotiated price taking effect two years after the selection year. For 2026, the first year in which negotiated prices become effective, CMS selected 10 high-cost Medicare Part D products in 2023, negotiations began in 2024, and the negotiated maximum fair price for each product has been announced. These negotiations resulted in significant price reductions for the products from their 2023 list prices, ranging from 38 to 79 percent, with an average price reduction of 59.4 percent. CMS has selected 15 additional Medicare Part D drugs for negotiated maximum fair pricing in 2027. For 2028, an additional 15 drugs, which may be covered under either Medicare Part B or Part D, will be selected, and for 2029 and subsequent years, 20 Part B or Part D drugs will be selected. Negotiations for Medicare Part D products begin in 2024 with the negotiated price taking effect in 2026, and negotiations for Medicare Part B products begin in 2026 with the negotiated price taking effect in 2028. In August 2023, HHS announced the 10 Medicare Part D drugs and biologics that it selected for

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negotiations, and by October 1, 2023, each manufacturer of the selected drugs signed a manufacturer agreement to participate in the negotiations. HHS announced the negotiated maximum fair prices on August 15, 2024, and this price cap, which cannot exceed a statutory ceiling price, came into effect on January 1, 2026. 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 and in November 2024, CMS finalized regulations pertaining to these inflation rebates. 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. Further, in July 2025, the OBBBA was signed into law, and restored immediate deductibility of domestic research and development expenditures, while foreign expenditures will continue to be capitalized and amortized over fifteen years. The OBBBA is expected to reduce Medicaid spending and enrollment by implementing work requirements for some beneficiaries, capping state-directed payments, reducing federal funding, and limiting provider taxes used to fund the program. The OBBBA also narrows access to ACA marketplace exchange enrollment and declined to extend the enhanced subsidies for individuals purchasing health insurance coverage in ACA marketplaces, which expired in 2025. Additionally, in June 2024, the U.S. Supreme Court overturned the longstanding Chevron doctrine, under which courts were required to give deference to regulatory agencies’ reasonable interpretations of ambiguous federal statutes. This decision could result in additional legal challenges to current regulations and guidance issued by federal agencies applicable to our operations, including those issued by the FDA. It is unclear to what extent other statutory, regulatory, and administrative initiatives will be enacted and implemented in the future.

We expect that additional state and federal healthcare reform measures will be adopted in the future.

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.

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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, 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.

Employees and Human Capital Resources

As of January 31, 2026, we had 104 employees. Of these employees, 72 were primarily engaged in research and development activities and 33 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 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.