Quarterly Report for Quarter Ending September 30, 2025 (Form 10-Q)

Management's Discussion and Analysis of Financial Condition and Results of Operations

You should read the following discussion of our financial condition and results of operations in conjunction with the condensed consolidated financial statements and related notes included elsewhere in this Quarterly Report, as well as our audited consolidated financial statements and the related notes included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission ("SEC"). The following discussion contains forward-looking statements that reflect our current plans, forecasts, estimates and beliefs and involve risks and uncertainties. Our historical results are not necessarily indicative of the results that may be expected for any period in the future. Our actual results, outcomes and the timing of events could differ materially from those discussed in the forward-looking statements. Factors that could cause or contribute to these differences include those discussed below and elsewhere in this Quarterly Report, particularly in the section titled "Special Note Regarding Forward Looking Statements" and "Risk Factors." We urge you to consider these factors carefully in evaluating the forward-looking statements contained in this Quarterly Report. Forward-looking statements are not historical facts, reflect our current views with respect to future events, and apply only as of the date made. We do not intend, and undertake no obligation, to update these forward-looking statements, except as required by law. Unless the context requires otherwise, references to "we," "us," "our," "Apogee" or "the Company" refer to Apogee Therapeutics, Inc. and its subsidiaries.

This Quarterly Report contains references to our programs, which are used interchangeably to refer to our clinical programs within our pipeline and our products under development.

Overview

We are a clinical stage biotechnology company advancing optimized, novel biologics with the potential for differentiated efficacy and dosing in the largest inflammatory and immunology ("I&I") markets, including for the treatment of atopic dermatitis ("AD"), asthma, eosinophilic esophagitis ("EoE"), chronic obstructive pulmonary disease ("COPD"), and other I&I indications. Our antibody programs are designed to overcome limitations of existing therapies by targeting well-established mechanisms of action and incorporating advanced antibody engineering to optimize half-life and other properties.

Our pipeline comprises multiple antibody programs being developed initially for the treatment of I&I indications as monotherapies and combinations, including APG777, APG279, APG273, APG990, APG333 and APG808. With four validated targets in our portfolio, we are seeking to achieve best-in-class efficacy and dosing through monotherapies and combinations of our novel antibodies. Based on a broad pipeline and depth of expertise, we believe we can deliver value and meaningful benefit to patients underserved by today's standard of care. We believe each of our programs has potential for broad application across multiple I&I indications.

APG777 - anti-IL13 antibody, same mechanism of action as EBGLYSS (lebrikizumab)

APG777 is a subcutaneous ("SQ") extended half-life monoclonal antibody ("mAb") targeting IL-13. In August 2023, we announced the dosing of our first participant in our first clinical trial for APG777. In 2024, we announced positive interim safety and pharmacokinetic ("PK") data from this trial with APG777 demonstrating a potential best-in-class PK profile, including a half-life of 77 days, supporting the potential for every three- to six- month maintenance dosing in AD. Single doses of APG777 demonstrated a deep and sustained effect on pharmacodynamic ("PD") markers out to approximately 12 months. APG777 was well-tolerated across all dose groups. In May 2024, we announced the dosing of our first participant in the Phase 2 APEX trial. In July 2025, we announced positive 16-week data from the Part A portion of the APEX Phase 2 clinical trial of APG777.

The APEX trial is a randomized, placebo-controlled study evaluating APG777 in patients with moderate-to-severe AD. Part A of the trial enrolled 123 adult patients who were randomized 2:1 to APG777 versus placebo and received an induction regimen dosing of 720mg at Weeks 0 and 2, followed by 360mg at Weeks 4 and 12. The primary endpoint for the induction arm of Part A was percentage change in Eczema Area Severity Index ("EASI") score from baseline at Week 16. Secondary endpoints included EASI-75, EASI-90, Validated Investigator Global Assessment ("vIGA") 0/1 and Itch Numeric Rating Scale ("NRS") at Week 16. In non-head-to-head trial comparisons, the initial 16-week findings from Part A include efficacy results, which compare favorably versus standard of care across endpoints as well as rapid onset of itch relief and lesion reduction, and a favorable safety profile consistent with its class.

The trial met its primary endpoint, with APG777 showing significantly greater least squares mean percent change from baseline at Week 16 with an EASI reduction of 71.0% compared to placebo of 33.8% (p < 0.001). APG777 showed the highest absolute and placebo-adjusted EASI-75 of any biologic in a 16-week global study with 66.9% of participants treated with APG777 achieving EASI-75 compared to 24.6% on placebo (p < 0.001). Pre-specified sensitivity analysis showed consistent results in both moderate and severe patients based on baseline EASI score. The results demonstrated a vIGA 0/1 of 34.9% compared to placebo of 17.3% (p < 0.05) and an

EASI-90 of 33.9% compared to placebo of 14.7% (p < 0.05). Treatment of patients with APG777 led to rapid onset of itch relief and achieved a statistically significant reduction by Week 1, with a 50.7% reduction of Itch NRS from baseline compared to placebo of 23.2% (p < 0.01) at Week 16. APG777 was well tolerated, with 56.1% of APG777-exposed patients experiencing treatment-emergent adverse events ("TEAEs") (vs. 63.4% in placebo). The most common TEAEs, occurring in more than 5% of patients, were non-infective conjunctivitis (14.6% vs. 2.4% in placebo), upper respiratory tract infection (8.5% vs 12.2% in placebo), nasopharyngitis (4.9% vs. 12.2% in placebo), and pain in extremity (0.0% vs. 7.3% in placebo) with the latter three being numerically lower in APG777 treated patients compared to placebo. Serious TEAEs were rare for APG777-exposed patients (1.2% vs. 2.4% in placebo). The discontinuation rate due to adverse events was low for APG777-exposed patients (2.4%). There were no injection site reactions in the APG777 treated group.

All Part A patients that benefited from treatment in the induction arm will have the opportunity to continue to APG777 maintenance treatment, which will evaluate three and six-month dosing intervals. In February 2025, we also announced that we had commenced dosing of the Part B portion of the APEX Phase 2 trial, and, in October 2025, we announced that we had increased the expected patient population to 320 patients. We expect to complete enrollment in the Part B portion of the APEX Phase 2 trial by the end of 2025. Part B is testing a higher and a lower dose of APG777. We anticipate topline maintenance data from Part A in the first quarter of 2026, 16-week topline induction data from Part B in the second quarter of 2026 and initiation of a Phase 3 trial in AD in the second half of 2026.

In April 2025, we initiated a Phase 1b trial in patients with asthma with topline results expected in the first quarter of 2026. Results from this trial, in addition to topline induction data from the Part B portion of the APEX Phase 2 trial in AD, will allow us to determine dose selections for further expansion indications in 2027 and beyond, including but not limited to asthma and EoE. We expect to announce plans for Phase 2b trials in asthma and EoE in 2026. Based on our clinical data, we expect to further evaluate additional opportunities to develop APG777 for other I&I indications, including alopecia areata, chronic rhinosinusitis with nasal polyps ("CRSwNP"), chronic spontaneous urticaria, and prurigo nodularis.

In addition, we plan to evaluate APG777 in combination with other investigational therapies within our pipeline to potentially enable greater efficacy for I&I conditions. The first of these combinations is APG279, which combines APG777 with APG990, our novel, SQ, half-life extended mAb targeting OX40L.

APG990 - anti-OX40L antibody, same mechanism of action as amlitelimab and APG279, a potential combination therapy of APG777 + APG990

APG990 is an SQ extended half-life mAb that utilizes advanced antibody engineering to target OX40L. In August 2024, we initiated a Phase 1 clinical trial of APG990 in healthy volunteers and in March 2025, we announced positive interim safety and PK data from the APG990 Phase 1 clinical trial. PK data showed a half-life of approximately 60 days across doses tested. APG990, in single doses up to 1,200mg, was well tolerated and showed a favorable safety profile, consistent with other assets targeting OX40L.

We plan to develop APG777 and APG990 ("APG279") together as a potential first-in-class coformulation for the treatment of AD by combining deep and sustained inhibition of Type 2 inflammation via APG777's inhibition of IL-13 with broader inhibition of Type 1-3 inflammation through APG990's inhibition of OX40L. APG279 has been shown to retain stability, injectability, and convenience of individual components in preclinical studies. In preclinical studies, APG279 has also demonstrated broad inhibition of Type 1, Type 2 and Type 3 inflammation, similar to what was seen with Janus kinase ("JAK") inhibition, but with potential for better tolerability than JAK inhibitors. In preclinical toxicology studies, the combination of APG777 and APG990 showed no findings at any dose level, including the highest dose tested of 150-mg/kg per agent per week. We believe these combined mechanisms offer the potential for improved clinical responses over monotherapy while our planned approach of coformulating two extended half-life mAbs holds the potential for best-in-class dosing.

In July 2025, we announced that we commenced dosing in the Phase 1b trial of APG279 against DUPIXENT in approximately 50 patients with moderate-to-severe AD with a data readout expected in the second half of 2026. The initial clinical trial of APG279 is being conducted as a coadministration of APG777 and APG990. We plan to advance the development of APG279 in future studies as a coformulation. The PK data for APG990, when considered together with APG279 coformulation data, provides the potential for dosing the combination two to four times per year with a single 2 mL coformulated injection.

APG333 - anti-TSLP antibody, same mechanism of action as TEZPIRE (tezepelumab) and APG273, a potential combination therapy of APG777 + APG333

APG333 is a novel, SQ extended half-life mAb targeting thymic stromal lymphopoietin ("TSLP"), an epithelial cell-derived cytokine that has emerged as an attractive, clinically validated target for the treatment of I&I indications because the target plays an

important role in promoting immune cell recruitment and activation. In addition, a TSLP-targeting mAb may be used in combination with other mAbs for potentially greater efficacy in broader populations. TSLP inhibition has been clinically validated, with one approved product on the market for the treatment of severe asthma without biomarker or phenotype restrictions.

In December 2024, we initiated a Phase 1 clinical trial of APG333 in healthy volunteers, and in November 2025, we announced positive interim safety, PK and PD results from the clinical trial. APG333 demonstrated a half-life of approximately 55 days, supporting the potential for every three- and six- month dosing. In addition, key biomarkers of eosinophils and IL-5 showed depth of suppression in line with TSLP analogs and durability out to 6 months (limit of available follow-up).

APG333, with single doses of up to 1,000 mg, was well tolerated across the four cohorts. The most common TEAEs occurring in ≥10% of APG333 treated participants were headache and upper respiratory tract infection. TEAEs were generally mild and self-limited and there were no dose dependent trends in TEAEs seen. There were no Grade 3 TEAEs or severe adverse events; and no adverse events led to study discontinuation.

The Phase 1 interim clinical trial results support development of a quarterly or less frequently dosed co-formulation of APG273 (APG777+APG333) for respiratory indications.

APG808 - anti-IL4Rα antibody, same mechanism of action as DUPIXENT

APG808 is an SQ extended half-life mAb targeting IL-4Rα, a target with clinical validation across eight different Type 2 allergic diseases. In March 2024, we commenced dosing of the first healthy volunteers in the APG808 Phase 1 trial and in September 2024, we commenced dosing of the first asthma patients as a cohort in that Phase 1 trial. In December 2024, we announced positive interim safety, PK and PD data from the Phase 1 trial. APG808 demonstrated a potential best-in-class PK profile, including a half-life of approximately 55 days at projected, clinically relevant steady state exposures, supporting the potential for every two- to three-month maintenance dosing. Single doses of APG808 demonstrated a deep and sustained effect on PD markers out to approximately three months (longest follow-up available at time of data cut). APG808 was well-tolerated across all dose groups.

In May 2025, we announced positive interim results from the Phase 1b trial of APG808 in patients with mild-to-moderate asthma. The trial was a double-blind, placebo-controlled, multiple-dose trial, which evaluated the safety and tolerability of APG808 in 22 adult patients with mild-to-moderate asthma. The trial also evaluated fractional exhaled nitric oxide concentration ("FeNO"), thymus and activation-regulated chemokine ("TARC"), and pSTAT6. Participants were randomized 3:1, receiving 600mg of APG808 or placebo on day 1 and day 29.

The results demonstrated that APG808 was well-tolerated, with multiple doses of APG808 resulting in rapid suppression of FeNO, a biomarker of Type 2 inflammation that is associated with exacerbations in asthma, with a maximal robust FeNO decrease from baseline of 53% and sustained FeNO decrease from baseline of 50% at 12 weeks. APG808 also demonstrated sustained and near-complete reduction in pSTAT6 as well as deep reduction of TARC maintained through 12 weeks. The most common TEAEs observed were headache, injection site erythema, and upper respiratory tract infections. There were no Grade 3 TEAEs or severe adverse events, and no adverse events led to study discontinuation.

APG808's optimized PK profile coupled with FeNO suppression out to 12-weeks reinforces the potential for 2-months or longer maintenance dosing, offering a significant advantage compared to the current bi-weekly standard of care.

Funding and Capital Resources

Since our inception in February 2022, we have devoted substantially all of our resources to raising capital, organizing and staffing our company, business and scientific planning, conducting discovery and research activities, acquiring product programs, establishing and protecting our intellectual property portfolio, developing and progressing our pipeline, establishing arrangements with third parties for the manufacture of our product candidates and component materials, and providing general and administrative support for these operations. We do not have any product candidates approved for sale and have not generated any revenue from product sales. To date, we have funded our operations primarily with proceeds from the issuance of preferred units and sale of common stock. Prior to our IPO, we received gross proceeds of $169.0 million from sales of our preferred units. On July 13, 2023, our Registration Statement on Form S-1, as amended (File Nos. 333-272831 and 333-273236) (the "IPO Registration Statement"), relating to our IPO was declared effective by the SEC. Pursuant to the IPO Registration Statement, we issued and sold an aggregate of 20,297,500 shares of common stock (inclusive of 2,647,500 shares pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a public offering price of $17.00 per share, for aggregate net proceeds of $315.4 million after deducting underwriting discounts and commissions and other offering expenses.

On March 7, 2024, our Registration Statement on Form S-1, as amended (File Nos. 333-277664 and 333-277763) (the "2024 Registration Statement"), relating to our public offering (the "March 2024 Offering") was declared effective by the SEC. Pursuant to the 2024 Registration Statement, we issued and sold an aggregate of 7,790,321 shares of common stock (inclusive of 1,016,128 shares pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a public offering price of $62.00 per share, for aggregate net proceeds of $450.0 million after deducting underwriting discounts and commissions and other offering expenses.

On October 10, 2025, pursuant to our Registration Statement on Form S-3, which became effective in August 2024 (File No 333-281503), we issued and sold an aggregate of 8,048,782 shares of common stock (inclusive of 1,097,561 shares of common stock pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a public offering price of $41.00 per share, and, in lieu of common stock to certain investors, pre-funded warrants to purchase up to 365,853 shares of common stock at a public offering price of $40.99999 per pre-funded warrant (the "October 2025 Offering"). The pre-funded warrants have an exercise price of $0.00001 per share and are exercisable immediately. The aggregate net proceeds from the offering were $324.1 million after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company.

We have incurred significant operating losses since inception. Our ability to generate sufficient product revenue to achieve profitability will depend heavily on the successful development and eventual commercialization of any product candidates we may develop. We generated a net loss of $186.5 million for the nine months ended September 30, 2025. As of September 30, 2025, we had an accumulated deficit of $492.4 million. We expect to continue to incur significantly increased expenses for the foreseeable future if and as we:

We will not generate revenue from product sales unless and until we successfully initiate and complete clinical development and obtain regulatory approval for any product candidates. If we obtain regulatory approval for any of our product candidates and do not enter into a commercialization partnership, we expect to incur significant expenses related to developing our commercialization capability to support product sales, manufacturing, marketing, and distribution. Further, we expect to incur additional costs associated with operating as a public company, including increased costs of accounting, audit, legal, regulatory and tax-related services associated with compliance with exchange listing and SEC requirements, director and officer insurance costs and investor and public relations costs.

As a result, we will need substantial additional funding to support our continued operations and growth strategy. Until such a time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through the sale of equity, debt

financings or other capital sources, including licensing arrangements, royalty financings, collaborations with other companies or other strategic transactions. We may be unable to raise additional funds or enter into such other agreements on favorable terms, or at all. If we fail to raise capital or enter into such agreements as, and when, needed, we may have to significantly delay, scale back or discontinue the development and commercialization of one or more of our product candidates.

Because of the numerous risks associated with product development, we are unable to accurately predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

We expect that our cash and cash equivalents of $107.9 million, marketable securities of $419.4 million and long-term marketable securities of $61.6 million as of September 30, 2025, in addition to the $324.1 million in net proceeds from the October 2025 Offering, will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into the second half of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. See "Liquidity and Capital Resources" for further information.

Reorganization

Apogee Therapeutics, LLC was formed as a limited liability company under the laws of the State of Delaware in February 2022. Apogee Therapeutics, Inc. was incorporated in June 2023 in connection with our IPO to serve as a holding company that would wholly own the assets of Apogee Therapeutics, LLC. Prior to July 13, 2023, our business was conducted by Apogee Therapeutics, LLC and its subsidiary at the time, Apogee Biologics, Inc. In July 2023, in connection with our IPO, we completed a series of transactions which are referred to, collectively, as the "Reorganization," and pursuant to which Apogee Therapeutics, Inc., became the parent and holding company that wholly owns the assets of Apogee Therapeutics, LLC, including stock of its subsidiary at the time, Apogee Biologics, Inc. In connection with our Reorganization:

Effective December 31, 2024, Apogee Biologics, Inc. merged with and into Apogee Therapeutics, Inc. with Apogee Therapeutics, Inc. surviving the merger.

Collaboration, License and Services Agreements

Paragon Option Agreements

In February 2022, we entered into an antibody discovery and option agreement with Paragon Therapeutics, Inc. ("Paragon"), which was subsequently amended in November 2022 (as amended, the "2022 Option Agreement"). Under the terms of the 2022 Option Agreement, Paragon identifies, evaluates and develops antibodies directed against certain mutually agreed therapeutic targets of interest to us. The 2022 Option Agreement initially included two selected targets, IL-13 and IL-4Rα, and was subsequently amended in November 2022 to include an additional selected target, OX40L. Under the 2022 Option Agreement, we have the exclusive option to, on a research program-by-research program basis, be granted an exclusive, worldwide license to all of Paragon's right, title and interest in and to the intellectual property resulting from the applicable research program to develop, manufacture and commercialize the antibodies and products directed to the selected targets (each, an "Option"). From time to time, we can choose to add additional targets to the collaboration by mutual agreement with Paragon.

Pursuant to the terms of the 2022 Option Agreement, the parties initiated certain research programs that generally focused on a particular target (each, a "Research Program"). Each Research Program is aimed at discovering, generating, identifying and/or

characterizing antibodies directed to the respective target. For each Research Program, the parties established a research plan that sets forth the activities that will be conducted, and the associated research budget (each, a "Research Plan"). Upon execution of the 2022 Option Agreement, we agreed with Paragon on an initial Research Plan that outlined the services that will be performed commencing at inception of the arrangement related to IL-13 and IL-4Rα. The Research Plan for OX40L was agreed to prior to December 31, 2022. Our exclusive option with respect to any future Research Program is exercisable at our sole discretion at any time during the period beginning on the initiation of activities under the associated Research Program and ending a specified number of days following the delivery of the data package from Paragon related to the results of the Research Plan activities (the "Option Period"). There is no payment due upon exercise of an Option pursuant to the 2022 Option Agreement.

In consideration for the exclusive options granted under the 2022 Option Agreement, we paid an upfront cash amount of $1.3 million and issued 1,250,000 common units to Paragon. Paragon was also entitled to up to an additional 3,750,000 of common units in exchange for the rights granted under the 2022 Option Agreement, which were issued in connection with the closings of the additional tranches of the Series A Preferred Unit financing. Under the 2022 Option Agreement, on a Research Program-by-Research Program basis following the finalization of the Research Plan for each respective Research Program, we are required to pay Paragon a nonrefundable fee in cash of $0.5 million. We are also obligated to compensate Paragon on a quarterly basis for its services performed under each Research Program based on the actual costs incurred.

In November 2023, we entered into an additional antibody discovery and option agreement with Paragon (the "2023 Option Agreement" and together with the 2022 Option Agreement, collectively, the "Option Agreements"). Under the terms of the 2023 Option Agreement, Paragon identifies, evaluates and develops antibodies directed against certain mutually agreed therapeutic targets of interest to us. The 2023 Option Agreement initially includes one target, TSLP. Under the 2023 Option Agreement, we have the exclusive option to, on a research program-by-research program basis, be granted an exclusive, worldwide license to all of Paragon's right, title and interest in and to the intellectual property resulting from the applicable research program to develop, manufacture and commercialize the antibodies and products directed to the selected targets. From time to time, we can choose to add additional targets to the collaboration by mutual agreement with Paragon.

Pursuant to the terms of the 2023 Option Agreement, the parties may initiate Research Programs. Each Research Program will be aimed at discovering, generating, identifying and/or characterizing antibodies directed to the respective target. For each Research Program, the parties must establish a Research Plan. In January 2024, we agreed on an initial Research Plan with Paragon that outlined the services that will be performed commencing at inception of the arrangement related to TSLP. Our exclusive option with respect to each Research Program is exercisable at our sole discretion at any time during the period beginning on the initiation of activities under the associated Research Program and ending a specified number of days following the delivery of the data package from Paragon related to the results of the Research Plan activities. There is no payment due upon exercise of an Option pursuant to the 2023 Option Agreement.

Under the 2023 Option Agreement, on a Research Program-by-Research Program basis following the finalization of the Research Plan for each respective Research Program, we are required to pay Paragon a nonrefundable fee in cash of $2.0 million. We are also obligated to compensate Paragon on a quarterly basis for its services performed under each Research Program based on the actual costs incurred. We expense the service fees as the associated costs are incurred when the underlying services are rendered. In January 2024, we finalized the Research Plan with Paragon related to the TSLP target. As such, we made a one-time non-refundable payment of $2.0 million to Paragon in the first quarter of 2024.

Unless terminated earlier, the Option Agreements shall continue in force on a Research Program-by-Research Program basis until the earlier of: (i) the end of the Option Period for such Research Program, as applicable, if such Option is not exercised by us; and (ii) the effective date of the license agreement for such Research Program if we exercise our Option with respect to such Research Program (the "Term"). Upon the expiration of the Term for all then-existing Research Programs, the applicable Option Agreement will automatically expire in its entirety. We may terminate either Option Agreement or any Research Program at any time for any or no reason upon 30 days' prior written notice to Paragon, provided that we must pay certain unpaid fees due to Paragon upon such termination, as well as any non-cancellable obligations reasonably incurred by Paragon in connection with its activities under any terminated Research Program. Each party has the right to terminate either Option Agreement or any Research Program upon (i) 30 days' prior written notice of the other party's material breach that remains uncured for the 30-day period and (ii) the other party's bankruptcy.

Paragon License Agreements

In November 2022, we exercised our option available under the 2022 Option Agreement with respect to the IL-13 Research Program. Upon such exercise, the parties entered into an associated license agreement (the "IL-13 License Agreement"). In April 2023, we exercised our option available under the 2022 Option Agreement with respect to the IL-4Rα Research Program and the OX40L Research Program. Upon such exercise, the parties entered into associated license agreements (the "IL-4Rα License Agreement" and the "OX40L License Agreement," respectively). In August 2024, we exercised our option available under the 2023 Option Agreement

with respect to the TSLP Research Program and entered into the associated license agreement (the "TSLP License Agreement," and collectively with the IL-13 License Agreement, the IL-4Rα License Agreement and the OX40L License Agreement, the "License Agreements"). Under the terms of the License Agreements, Paragon granted to us an exclusive, worldwide, royalty-bearing, sublicensable right and license with respect to certain information, patent rights and sequence information related to antibodies directed at the respective target to use, make, sell, import, export and otherwise exploit the antibodies directed at the respective target. Pursuant to the License Agreements, we granted to Paragon a similar license (except that such license we granted to Paragon is non-exclusive) to the respective licenses with respect to multispecific antibodies that are directed at the respective targets and one or more other antibodies. We were also granted a right of first negotiation with Paragon concerning the development, license and grant of rights to certain multispecific antibodies associated with each respective license. We are solely responsible for the continued development, manufacture and commercialization of products at our own cost and expense for each licensed target.

Under the IL-13 License Agreement, the IL-4Rα License Agreement and the OX40L License Agreement, we are obligated to pay Paragon up to $3.0 million upon the achievement of specific development and clinical milestones for the first product under each of the License Agreements that achieves such specified milestones, including a payment of $1.0 million upon the nomination of a development candidate and $2.0 million upon the first dosing of a human patient in a Phase 1 trial. Under the TSLP License Agreement, we are obligated to pay Paragon up to $28.0 million upon the achievement of specific development and clinical milestones for the first product, including a payment of $3.0 million upon the nomination of a development candidate and $5.0 million upon the first dosing of a human patient in a Phase 1 trial.

Upon execution of the IL-13 License Agreement, we paid Paragon a $1.0 million fee for the nomination of a development candidate. In August 2023, we announced the dosing of our first participants in the Phase 1 trial of APG777 and made a milestone payment of $2.0 million in the fourth quarter of 2023. In November 2023, we finalized the nomination of a development candidate under the IL-4Rα License Agreement and made a milestone payment of $1.0 million to Paragon in the fourth quarter of 2023. In March 2024, we announced the dosing of our first participants in a Phase 1 trial of APG808 and made a milestone payment of $2.0 million to Paragon in the first quarter of 2024. In May 2024, we finalized the nomination of a development candidate under the OX40L License Agreement and made a milestone payment of $1.0 million to Paragon in the second quarter of 2024. In August 2024, we announced the dosing of our first participants in the Phase 1 trial of APG990 and made a milestone payment of $2.0 million in the third quarter of 2024. In October 2024, we finalized the nomination of a development candidate under the TSLP License Agreement and made a milestone payment of $3.0 million to Paragon in the fourth quarter of 2024. In December 2024, we announced the dosing of our first participant in the Phase 1 trial of APG333 and made a milestone payment of $5.0 million in the fourth quarter of 2024.

We are also obligated to pay royalties to Paragon equal to a low-single digit percentage of net sales of any products under each of the respective License Agreements, and Paragon has a similar obligation to pay royalties to us with respect to each of the multispecific licenses. Royalties are due on a product-by-product and country-by-country basis beginning upon the first commercial sale of each product and ending on the later of (i) 12 years after the first commercial sale of such product in such country and (ii) expiration of the last valid claim of a patent covering such product in such country (the "Royalty Term").

Unless earlier terminated, the License Agreements remain in effect until the expiration of the last-to-expire Royalty Term for any and all products associated with the respective license. We may terminate the agreement in its entirety or on a country-by-country or product-by-product at any time for any or no reason upon 60 days' advance written notice to Paragon, and either party may terminate for (i) the other party's material breach that remains uncured for 90 days (or 30 days with respect to any failure to make payments) following notice of such breach and (ii) the other party's bankruptcy. Upon any termination prior to the expiration of a License Agreement, all licenses and rights granted pursuant to such License Agreement will automatically terminate and revert to the granting party and all other rights and obligations of the parties will terminate.

We concluded that each of the License Agreements constitutes an asset acquisition of in-process research and development assets with no alternative future use. Each of the arrangements did not qualify as a business combination because substantially all of the fair value of the assets acquired was concentrated in the license which comprises a single identifiable asset. Therefore, the aggregate acquisition cost for each license was recognized as research and development expense.

Biologics Master Services Agreement - WuXi Biologics (Hong Kong) Limited

In June 2022, Paragon and WuXi Biologics (Hong Kong) Limited ("WuXi Biologics") entered into a biologics master services agreement (the "WuXi Biologics MSA"), which was subsequently novated to us by Paragon in the second quarter of 2023. The WuXi Biologics MSA governs all development activities and GMP manufacturing and testing for APG777, APG990, APG333 and APG808 , as well as potential future product candidates, on a work order basis. Under the WuXi Biologics MSA, we are obligated to pay WuXi Biologics a service fee and all non-cancellable obligations in the amount specified in each work order associated with the agreement for the provision of services.

The WuXi Biologics MSA terminates on the later of (i) June 20, 2027 or (ii) the completion of services under all work orders executed by the parties prior to June 20, 2027, unless terminated earlier. The term of each work order terminates upon completion of the services under such work order, unless terminated earlier. We can terminate the WuXi Biologics MSA or any work order at any time upon 30 days' prior written notice and immediately upon written notice if WuXi Biologics fails to obtain or maintain required material governmental licenses or approvals. Either party may terminate a work order (i) at any time upon six months' prior notice with reasonable cause, provided however that if WuXi Biologics terminates a work order in such manner, no termination or cancellation fees shall be paid by us and (ii) immediately for cause upon (a) the other party's material breach that remains uncured for 30 days after notice of such breach, (b) the other party's bankruptcy or (c) a force majeure event that prevents performance for a period of at least 90 days.

Cell Line License Agreement - WuXi Biologics (Hong Kong) Limited

In June 2022, Paragon and WuXi Biologics entered into a cell line license agreement (the "Cell Line License Agreement"), which was subsequently novated to us by Paragon in the second quarter of 2023. Under the Cell Line License Agreement, we received a non-exclusive, worldwide, sublicensable license to certain of WuXi Biologics' know-how, cell line, biological materials (the "WuXi Biologics Licensed Technology") and media and feeds to make, have made, use, sell and import certain therapeutic products produced through the use of the cell line licensed by WuXi Biologics under the Cell Line License Agreement (the "WuXi Biologics Licensed Products"). Specifically, the WuXi Biologics Licensed Technology is used to manufacture APG777, APG990, APG333 and APG808 product candidates.

In consideration for the license, we have paid WuXi Biologics a non-refundable license fee of $150,000. Additionally, if we manufacture all of our commercial supplies of bulk drug product with a manufacturer other than WuXi Biologics or its affiliates, we are required to make royalty payments to WuXi Biologics in an amount equal to a fraction of a single digit percentage of global net sales of WuXi Biologics Licensed Products manufactured by a third-party manufacturer (the "Royalty"). If we manufacture part of our commercial supplies of the WuXi Biologics Licensed Products with WuXi Biologics or its affiliates, then the Royalty will be reduced accordingly on a pro rata basis.

The Cell Line License Agreement will continue indefinitely unless terminated (i) by us upon six months' prior written notice and our payment of all undisputed amounts due to WuXi Biologics through the effective date of termination, (ii) by WuXi Biologics for a material breach by us that remains uncured for 60 days after written notice, (iii) by WuXi Biologics if we fail to make a payment and such failure continues for 30 days after receiving notice of such failure, or (iv) by either party upon the other party's bankruptcy.

Master Services Agreement and Project Specific Agreements - Samsung Biologics Limited

In March 2025, we entered into a Master Services Agreement (the "Samsung Biologics MSA"), made effective as of February 28, 2025, with Samsung Biologics Co., Ltd. ("Samsung Biologics"), pursuant to which Samsung Biologics will manufacture and supply us with APG777 drug substance (the "Samsung Biologics Product") for clinical development and commercial sale, if approved. We are obligated to pay Samsung Biologics service fees for each manufactured batch, as well as the costs of materials purchased by Samsung Biologics and expenses including testing and storage, which such costs and fees will be specified in Project Specific Agreements (each a "PSA").

Also in March 2025, we entered into a PSA (the "Initial PSA") with Samsung Biologics, made effective as of February 28, 2025, pursuant to which Samsung Biologics will produce clinical batches of the Samsung Biologics Product at its facility in Incheon, South Korea, perform process characterization and validation, and manufacture process performance qualification lots of the Samsung Biologics Product. Under the Initial PSA, we must purchase certain minimum quantities of the Samsung Biologics Product and have agreed to pay Samsung Biologics as determined pursuant to the terms of the Initial PSA. We have also agreed to enter into a separate PSA with Samsung Biologics for the manufacture of commercial supply of APG777 drug substance, which will provide for certain minimum purchase commitments for each year from 2029 to 2034. If we elect not to enter into the PSA for commercial supply, we will incur an exit fee in the high single digit millions. The Samsung Biologics MSA will terminate in February 2035, or, if a PSA is still in effect, when such PSA terminates, and may be extended upon mutual agreement of the parties. The Initial PSA will terminate in December 2034. We or Samsung Biologics may terminate the Samsung Biologics MSA or the Initial PSA in the event of an uncured material breach by, insolvency of or inability to perform due to a force majeure event by the other party. In the event all applicable PSAs have been terminated, Samsung Biologics has agreed to provide assistance with certain technology transfer matters, subject to exceptions. If we terminate the Samsung Biologics MSA or Initial PSA without cause, we will generally be responsible for paying the purchase price for our aggregate product commitment for the remainder of the term, less any amounts we have already paid.

For additional detail regarding the agreements described above, see the section titled "Notes to Condensed Consolidated Financial Statements-Other Significant Agreements" included elsewhere in this Quarterly Report.

Overview of Financial Results

Revenue

We have not generated any revenue from product sales and do not expect to generate any revenue from the sale of products for several years, if at all. If our development efforts for our programs are successful and result in regulatory approval or collaboration or license agreements with third parties, we may generate revenue in the future from product sales or payments from collaboration or license agreements that we may enter into with third parties, or any combination thereof.

Operating Expenses

Our operating expenses consist of (i) research and development expenses and (ii) general and administrative expenses.

Research and Development

Research and development expenses consist primarily of costs incurred in connection with the development and research of our programs. These expenses include:

We measure and recognize asset acquisitions or licenses to intellectual property that are not deemed to be business combinations based on the cost to acquire or license the asset or group of assets, which includes transaction costs. In an asset acquisition or license to intellectual property, the cost allocated to acquired in-process research and development, with no alternative future use is recognized as research and development expense on the acquisition date.

We expense research and development costs as incurred. Non-refundable advance payments that we make for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed, or when it is no longer expected that the goods will be delivered or the services rendered.

Our primary focus since inception has been the identification and development of our pipeline programs. Our research and development costs primarily consist of external costs, such as fees paid to Paragon under the Option Agreements and the License Agreements. We do not separately track or segregate the amount of costs incurred under the Option Agreements due to the early-stage and discovery nature of the services. We do not allocate personnel-related costs by program because these resources are used and these costs are deployed across multiple programs under development, and, as such, are not separately classified.

We expect that our research and development expenses will increase substantially for the foreseeable future as we continue to invest in research and development activities for our programs, and any potential future programs, including investments in manufacturing. The success of programs we may identify and develop will depend on many factors, including the following:

Any changes in the outcome of any of these variables with respect to the development of programs that we may identify could mean a significant change in the costs and timing associated with the development of such programs. For example, if the U.S. Food and Drug Administration ("FDA") or another regulatory authority were to require us to conduct clinical trials beyond those that we currently anticipate will be required for the completion of clinical development of a program, or if we experience significant delays in our clinical trials due to patient enrollment or other reasons, we would be required to expend significant additional financial resources and time on the completion of clinical development. We may never obtain regulatory approval for any of our programs.

General and Administrative

General and administrative expenses consist primarily of personnel-related expenses, including salaries, bonuses, and equity-based compensation, for individuals in our executive, finance, legal, operations, human resources, business development, commercial and other administrative functions. Other significant general and administrative expenses include legal fees relating to corporate matters, professional fees for accounting, auditing, tax and administrative consulting services, insurance costs and recruiting costs. These costs relate to the operation of the business, unrelated to the research and development function, or any individual program.

We expect that our general and administrative expenses will increase substantially for the foreseeable future as we increase our headcount to support the expected growth in our research and development activities and the potential commercialization of our product candidates, if approved. We also expect to continue incurring expenses associated with being a public company, including increased costs of accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance costs, and investor and public relations costs.

Other Income (Expense), Net

Interest Income

Interest income consists of interest income earned from our cash, cash equivalents, and marketable securities and amortization of investment discounts.

Income Taxes

Since our inception, we have not recorded any income tax benefits for the net losses we have incurred or for the research and development tax credits generated in each period as we believe, based upon the weight of available evidence, that it is more likely than not that all of our net operating loss ("NOL") carryforwards and the vast majority of our tax credit carryforwards will not be realized.

As of December 31, 2024, we had U.S. federal NOL carryforwards of approximately $68.1 million, which may be available to reduce future taxable income and have an indefinite carryforward period but are limited in their usage to an annual deduction equal to 80% of annual taxable income. We also had state net operating loss carryforwards of approximately $28.5 million, which will begin to expire in 2043 for state tax purposes. As of December 31, 2024, we also had U.S. federal and research and development tax credit carryforwards of approximately $10.5 million, which may be available to reduce future tax liabilities. We also had California research and development credit carryforwards of approximately $1.5 million. Additionally, we had Massachusetts research and development credit carryforwards of approximately $2.1 million. The U.S. federal and Massachusetts research and development tax credit carryforwards expire at various dates beginning in 2042 and the California research and development tax credit carryforwards do not expire. We have recorded a full valuation allowance against our net deferred tax assets at the balance sheet date.

Our provision for state income taxes was $0.1 million and $0.2 million for the three and nine months ended September 30, 2025, respectively. There was no provision for state income taxes for the three and nine months ended September 30, 2024.

On July 4, 2025, the One Big Beautiful Bill Act ("OBBBA") was signed into law. OBBBA introduces significant changes to U.S. income-tax legislation. Key provisions affecting the Company include (i) permanent immediate expensing of domestic research and experimental expenditures starting January 1, 2025, and (ii) 100 percent bonus depreciation for qualified property placed in service after January 19, 2025. We have completed our analysis of OBBBA's tax implications and concluded that the impact on our financial statements is immaterial.

Results of Operations

A discussion regarding our financial condition and results of operations for the three and nine months ended September 30, 2025 compared to the three and nine months ended September 30, 2024 is presented below.

Comparison of the Three Months Ended September 30, 2025 and 2024

Results of Operations

The following table summarizes our consolidated statements of operations for the periods presented (in thousands):

Research and Development Expense

The following table summarizes our research and development expenses incurred for the periods presented (in thousands):

Research and development expenses for the three months ended September 30, 2025 and 2024 were $54.2 million and $45.7 million, respectively. The increase of $8.5 million was primarily driven by further development of our APG777 program and increases in personnel costs and equity-based compensation, associated with the growth in our research and development team, partially offset by decreases in expenses related to the APG990/APG279, APG333/APG273 and APG808 programs.

Research and development expense related to the APG777 program increased by $7.8 million in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily driven by an increase in clinical trial-related expenses and clinical manufacturing activities to support our Phase 1 and Phase 2 clinical trials. Research and development expense related to the APG990/APG279 program decreased by $1.4 million in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily due to a decrease in expenses incurred under the Option Agreements and License Agreements, including a milestone payment of $2.0 million to Paragon in August 2024, related to the first dosing of human participants in a Phase 1 clinical trial, partially offset by an increase in clinical trial expenses. Research and development expense related to the APG333/APG273 program decreased by $7.3 million in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily due to a reduction in clinical manufacturing activities and a decrease in preclinical research and development expenses. Research and development expense related to the APG808 program decreased by $1.6 million in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily driven by a decrease in clinical manufacturing expenses.

External-discovery related costs and other expenses increased by $1.0 million in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily driven by an increase in professional service fees. Personnel-related expenses and equity-based compensation increased by $6.7 million and $3.3 million, respectively, in the three months ended September 30, 2025, compared to the three months ended September 30, 2024, primarily due to increased headcount and an increase in the fair value of equity awards granted.

General and Administrative Expense

The following table summarizes our general and administrative expenses for the periods presented (in thousands):

General and administrative expenses for the three months ended September 30, 2025 were $17.1 million, compared to $13.0 million for the three months ended September 30, 2024. The increase of $4.1 million was primarily due to increases in personnel-related expenses and equity-based compensation of $2.5 million and $2.8 million, respectively, primarily driven by increased headcount and an increase in the fair value of equity awards granted, partially offset by a $1.2 million decrease in legal and professional fees. The increase in total general and administrative expense was the result of the expansion of our operations to support the growth in our business.

Other Income, Net

Interest income decreased $3.4 million for the three months ended September 30, 2025, compared to the three months ended September 30, 2024, which was primarily related to interest on our cash, cash equivalents and marketable securities.

Comparison of the Nine Months Ended September 30, 2025 and 2024

The following table summarizes our consolidated statements of operations for the periods presented (in thousands):

Research and Development Expense

The following table summarizes our research and development expenses incurred for the periods presented (in thousands):

Research and development expenses for the nine months ended September 30, 2025 and 2024 were $156.3 million and $107.6 million, respectively. The increase of $48.7 million was primarily driven by further development of our APG777 program and increases in personnel costs and equity-based compensation, associated with the growth in our research and development team, partially offset by decreases in expenses related to the APG990/APG279, APG333/APG273 and APG808 programs.

Research and development expense related to the APG777 program increased by $30.3 million in the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, primarily driven by an increase in clinical trial-related expenses and clinical manufacturing activities to support our ongoing clinical trials. Research and development expense related to the APG990/APG279 program decreased by $6.3 million in the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, primarily due to a reduction in clinical manufacturing activities and a decrease in expenses incurred under the Option Agreements and License Agreements, which included milestone payments of $1.0 million and $2.0 million to Paragon, related to the nomination of a development candidate in May 2024, and the first dosing of human participants in a Phase 1 clinical trial in August 2024, respectively, partially offset by an increase in clinical trial expenses. Research and development expense related to the APG333/APG273 program decreased by $11.1 million in the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, primarily due to a reduction in clinical manufacturing activities and a decrease in expenses incurred under the Option Agreements and License Agreements, including a payment of $2.0 million to Paragon in January 2024 for the finalization of the TSLP research plan, partially offset by an increase in clinical trial expenses. Research and development expense related to the APG808 program decreased by $5.0 million in the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, primarily driven by a decrease in expenses incurred under the Option Agreements and License Agreements,

including a milestone payment of $2.0 million to Paragon in March 2024 for the first dosing of a human patient in a Phase 1 trial, as well as decreases in clinical trial and clinical manufacturing expenses.

External-discovery related costs and other expenses increased by $6.1 million in the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, primarily due to increases in non-program specific research and development expenses, travel and other employee related expenses, and professional service fees. Personnel-related expenses and equity-based compensation increased by $24.4 million and $10.1 million, respectively, in the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024, primarily due to increased headcount and an increase in the fair value of equity awards granted.

General and Administrative Expense

The following table summarizes our general and administrative expenses for the periods presented (in thousands):

General and administrative expenses for the nine months ended September 30, 2025 were $51.3 million, compared to $33.4 million for the nine months ended September 30, 2024. The increase of $17.9 million was primarily due to an increase in personnel costs and equity-based compensation of $8.0 million and $8.5 million, respectively, primarily driven by increased headcount and an increase in the fair value of equity awards granted. Additionally, other expenses increased by $2.4 million, primarily due to increases in rent expense, as well as travel and other employee related expenses. The increase in total general and administrative expenses was the result of the expansion of our operations to support the growth in our business.

Other Income, Net

Interest income decreased by $4.8 million for the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024, which was primarily related to interest on our cash, cash equivalents and marketable securities.

Liquidity and Capital Resources

Sources of Liquidity

Since our inception, we have incurred significant losses. We have not yet commercialized any of our product candidates, which are in various phases of early-stage development, and we do not expect to generate revenue from sales of any of our product candidates for several years, if at all. To date, we have financed our operations with the proceeds from the issuance of preferred units and the sale of common stock in our IPO, our March 2024 Offering, our ATM (as defined below) and our October 2025 Offering. As of September 30, 2025, we had cash and cash equivalents of $107.9 million, marketable securities of $419.4 million and long-term marketable securities of $61.6 million (excluding proceeds from our October 2025 Offering).

Prior to our IPO, we received gross proceeds of $169.0 million from sales of our preferred units. In connection with our IPO in July 2023, we issued and sold an aggregate of 20,297,500 shares of common stock (inclusive of 2,647,500 shares pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a price of $17.00 per share for aggregate net proceeds of $315.4 million, after deducting underwriting discounts and commissions and other offering expenses. In connection with our March 2024 Offering, we issued and sold an aggregate of 7,790,321 shares of common stock (inclusive of 1,016,128 shares pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a public offering price of $62.00 per share, for aggregate net proceeds of $450.0 million after deducting underwriting discounts and commissions and other offering expenses.

In August 2024, we entered into an Open Market Sale Agreement (the "Sale Agreement") with Jefferies LLC (the "Sales Agent"), pursuant to which we may offer and sell shares of common stock up to a maximum aggregate offering price of $300.0 million, from time to time, through an at the market offering program (the "ATM"). In December 2024, we sold 926,049 shares of common stock under the ATM at a price per share of $48.50 resulting in net proceeds of $43.6 million. In the three months ended September 30, 2025,

we sold 527,437 shares of common stock under the ATM for gross proceeds of $20.0 million, less commissions and other offering expenses of $0.6 million. As of September 30, 2025, $235.1 million remained available for sale under the Sale Agreement.

On October 10, 2025, pursuant to our Registration Statement on Form S-3, which became effective in August 2024 (File No 333-281503), we issued and sold an aggregate of 8,048,782 shares of common stock (inclusive of 1,097,561 shares of common stock pursuant to the exercise in full of the underwriters' option to purchase additional shares) at a public offering price of $41.00 per share, and, in lieu of common stock to certain investors, pre-funded warrants to purchase up to 365,853 shares of common stock at a public offering price of $40.99999 per pre-funded warrant. The pre-funded warrants have an exercise price of $0.00001 per share and are exercisable immediately. The aggregate net proceeds from the offering were $324.1 million after deducting underwriting discounts and commissions and other offering expenses payable by the Company.

Cash Flows

The following table provides information regarding our cash flows for the periods presented (in thousands):

Net Cash used in Operating Activities

Cash used in operating activities resulted primarily from our net losses adjusted for non-cash charges and changes in components of operating assets and liabilities, which are generally attributable to timing of payments, and the related effect on certain account balances, operational and strategic decisions and contracts to which we may be a party.

For the nine months ended September 30, 2025, operating activities used $164.8 million of cash, primarily due to a net loss of $186.5 million, net changes in our operating assets and liabilities of $10.6 million and amortization of discounts on marketable securities of $5.8 million. This was partially offset by non-cash charges of $34.3 million and $2.7 million for equity-based compensation and lease expense, respectively.

For the nine months ended September 30, 2024, operating activities used $103.5 million of cash, primarily due to a net loss of $114.9 million and amortization of discounts on marketable securities of $9.3 million. This was partially offset by a non-cash charge of $15.7 million for equity-based compensation and net changes in operating assets and liabilities of $4.0 million.

Net Cash provided by (used in) Investing Activities

For the nine months ended September 30, 2025, net cash provided by investing activities of $109.1 million was related to $367.3 million in maturities of marketable securities, partially offset by the $253.2 million purchase of marketable securities and $5.1 million purchase of property and equipment.

For the nine months ended September 30, 2024, net cash used in investing activities of $346.8 million was primarily related to the $588.9 million purchase of marketable securities, partially offset by $243.2 million in maturities of marketable securities.

Net Cash provided by Financing Activities

For the nine months ended September 30, 2025, financing activities provided $21.5 million of cash, primarily related to the issuance and sale of 527,437 shares of common stock, net of paid issuance costs, pursuant to the ATM.

For the nine months ended September 30, 2024, financing activities provided $450.8 million of cash, primarily related to the issuance and sale of 7,790,321 shares of common stock, net of paid issuance costs, in our March 2024 Offering.

Future Funding Requirements

To date, we have not generated any revenue from product sales. We do not expect to generate revenue from product sales unless and until we successfully complete preclinical and clinical development of, receive regulatory approval for, and commercialize a product candidate and we do not know when that will occur, if at all. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical and clinical activities. In addition, if we obtain regulatory approval for any product candidates, we expect to incur significant expenses related to product sales, marketing, and distribution to the extent that such sales, marketing and distribution are not the responsibility of potential collaborators. We expect to incur additional costs associated with operating as a public company. The timing and amount of our operating expenditures will depend largely on the factors set out above. For more information, see the section titled "Risk Factors-Risks Related to Our Limited Operating History, Financial Position and Capital Requirements."

Our funding requirements and timing and amount of our operating expenditures will depend on many factors, including, but not limited to:

Identifying potential programs and product candidates and conducting preclinical studies and clinical trials is a time consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve product sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of products that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds to achieve our business objectives.

Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, our stockholders' ownership interests could be diluted, and the terms of these securities may include liquidation or other preferences that could adversely affect our stockholders' rights.

Additional debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring debt, making capital expenditures or declaring dividends, and may require the issuance of warrants, which could potentially dilute our stockholders' ownership interests.

If we raise additional funds through strategic collaborations, licensing arrangements, royalty financings or other collaborations with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our business.

If we are unable to raise additional funds when needed or on acceptable terms, we may be required to delay, limit, suspend, or terminate our product development programs or any future commercialization efforts or grant rights to develop and market product candidates to third parties that we would otherwise prefer to develop and market ourselves.

As of September 30, 2025, we had $107.9 million of cash and cash equivalents, $419.4 million of marketable securities and $61.6 million of long-term marketable securities. Based on our current operating plan, as of the date of this Quarterly Report, we estimate that our existing cash, cash equivalents, marketable securities and long-term marketable securities will be sufficient to enable us to fund our operating expenses and capital expenditure requirements through at least the next 12 months following the issuance of our consolidated financial statements included elsewhere in this Quarterly Report. Moreover, based on our current operating plan, we estimate that such funds (including the $324.1 million in net proceeds from the October 2025 Offering) will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into the second half of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect.

Contractual Obligations and Other Commitments

We enter into contracts in the normal course of business with contract research organizations ("CROs"), contract manufacturing organizations ("CMOs") and other third parties for preclinical research studies and testing, clinical trials, manufacturing and other services. These contracts do not contain any minimum purchase commitments and provide for termination by us upon prior written notice. Payments due upon cancellation consist only of payments for services provided and expenses incurred up to the date of cancellation, including non-cancelable obligations of our service providers and, in some cases, wind-down costs. The exact amounts of such obligations are dependent on the timing of termination and the terms of the associated agreement. Accordingly, these payments are not disclosed as the amount and timing of such payments are not known.

Our agreements to license intellectual property include potential milestone payments that are dependent upon the development of products using the intellectual property licensed under the agreements and contingent upon the achievement of specific development and clinical milestones. As of September 30, 2025, we have incurred $17.0 million of the maximum aggregate potential milestone payments. We are also obligated to pay royalties to (i) Paragon at a royalty rate of a low single-digit percentage based on net sales of any products under the License Agreements, once commercialized and (ii) WuXi Biologics at a royalty rate of a fraction of a single digit percentage of global net sales of WuXi Biologics Licensed Products manufactured by a third-party manufacturer.

We do not have any off-balance sheet arrangements that are material or reasonably likely to become material to our financial condition or results of operations.

Critical Accounting Policies and Significant Judgments and Estimates

Our management's discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of these condensed consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, as well as the reported revenues recognized and expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

We define our critical accounting policies as those accounting principles generally accepted in the United States of America that are most critical to the judgments and estimates used in the preparation of our condensed consolidated financial statements. While our significant accounting policies are described in more detail in Note 2 to our condensed consolidated financial statements appearing elsewhere in this Quarterly Report, we believe that our most critical accounting policies are those relating to Research and Development

Expenses, which are described under the heading "Management's Discussion and Analysis of Financial Condition and Results of Operations - Critical Accounting Policies and Significant Judgment and Estimates" in our Annual Report on Form 10-K. There have been no material changes to our critical accounting policies from those described in the Annual Report on Form 10-K.

Recently Issued Accounting Pronouncements

We have reviewed all recently issued accounting standards and have determined that, other than as disclosed in Note 2 to our condensed consolidated financial statements included elsewhere in this Quarterly Report, such standards are not expected to have a material impact on our consolidated financial statements or do not otherwise apply to our operations.