10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2025

Commission File Number 001-39386

ALX ONCOLOGY HOLDINGS INC.

(Exact name of registrant as specified in its charter)

323 Allerton AvenueSouth San Francisco, California 94080

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: 650-466-7125

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

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

Common Stock, par value $0.001 per share ALXO The Nasdaq Global Select Market

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

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

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

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

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

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

Large accelerated filer ☐ Accelerated filer ☐

Non-accelerated filer ☒ Smaller reporting company ☒

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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

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

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

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

The aggregate market value of the registrant’s common stock held by non-affiliates of the registrant on June 30, 2025, the last business day of its most recently completed second fiscal quarter, was $18.0 million based on the closing sales price of the registrant’s common stock on that date.

The number of shares of registrant’s Common Stock outstanding as of March 2, 2026 was 131,608,278.

DOCUMENTS INCORPORATED BY REFERENCE

Certain portions of the registrant’s definitive proxy statement relating to the Company’s 2024 Annual Meeting of Stockholders, to be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 31, 2025, are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements. All statements other than statements of historical facts contained in this report, including statements regarding our future results of operations and financial position, business strategy, product candidates, planned preclinical studies and clinical trials, results of clinical trials, research and development costs, regulatory approvals, timing and likelihood of success, as well as plans and objectives of management for future operations, are forward-looking statements. These statements involve known and unknown risks, uncertainties and other important factors that are in some cases beyond our control and may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential,” or “continue” or the negative of these terms or other similar expressions. Forward-looking statements contained in this Annual Report include, but are not limited to, statements about:

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our financial performance;

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the sufficiency of our existing cash to fund our future operating expenses and capital expenditure requirements;

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the accuracy of our estimates regarding expenses, future revenue, capital requirements, and needs for additional financing;

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our plans relating to commercializing our product candidates, if approved, including the geographic areas of focus and our ability to grow a sales team;

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the implementation of our strategic plans for our business and product candidates;

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our ability to obtain and maintain regulatory approval of our product candidates and the timing or likelihood of regulatory filings and approvals, including our expectation to seek special designations, such as orphan drug designation, for our product candidates for various diseases;

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our reliance on third parties to conduct preclinical research activities, and for the manufacture of our product candidates;

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the beneficial characteristics, mechanisms of action, safety profile, efficacy and therapeutic effects of our product candidates;

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the progress and focus of our current and future clinical trials, and the reporting of data from those trials;

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our ability to advance product candidates into and successfully complete clinical trials;

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the ability of our clinical trials, including collaborations and investigator sponsored trials, to demonstrate the safety and efficacy of our product candidates, and other positive results;

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

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developments relating to our competitors and our industry, including competing product candidates and therapies;

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our plans relating to the further development and manufacturing of our product candidates, including additional indications that we may pursue;

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existing regulations and regulatory developments in the United States and other jurisdictions;

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our potential and ability to successfully manufacture and supply our product candidates for clinical trials and for commercial use, if approved;

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our continued reliance on third parties to conduct clinical trials of our product candidates, and for the manufacture of our product candidates;

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our plans and ability to obtain or protect intellectual property rights, including extensions of existing patent terms where available;

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the scope of protection we are able to establish and maintain for intellectual property rights, including our technology platform and product candidates;

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our ability to retain the continued service of our key personnel, the impacts of any executive officer changes, and to identify, hire, and then retain additional qualified personnel;

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the impact of macroeconomic conditions and global economic environment, such as inflation, interest rate changes, trade and other global disputes and interruptions, including related to tariffs and trade protection measures, U.S. federal government shutdowns, economic downturns, bank failures or instability in the financial services sector, or geopolitical risks, disasters, and medical or public health crises, such as the COVID-19 pandemic;

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our plans for and prospects of our acquisitions and other business development activities, and our ability to successfully capitalize on these opportunities;

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changes in our financial and internal controls; and

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our anticipated use of our existing cash and cash equivalents, short-term and long-term investments, and the funds available from our term loan.

We have based these forward-looking statements largely on our current expectations and projections about our business, the industry in which we operate and financial trends that we believe may affect our business, financial condition, results of operations and prospects, and these forward-looking statements are not guarantees of future performance or development. These forward-looking statements speak only as of the date of this Annual Report on Form 10-K and are subject to a number of risks, uncertainties and assumptions described in the section titled “Risk Factors” and elsewhere in this Annual Report on Form 10-K. Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely on these forward-looking statements as predictions of future events. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events or otherwise.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain, and you are cautioned not to unduly rely upon these statements.

Table of Contents

Page

PART I

Item 1. Business 1

Item 1A. Risk Factors 36

Item 1B. Unresolved Staff Comments 84

Item 1C. Cybersecurity 84

Item 2. Properties 85

Item 3. Legal Proceedings 85

Item 4. Mine Safety Disclosures 85

PART II

Item 6. [Reserved] 86

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 99

Item 8. Financial Statements and Supplementary Data 99

Item 9A. Controls and Procedures 131

Item 9B. Other Information 131

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 131

PART III

Item 10. Directors, Executive Officers and Corporate Governance 132

Item 11. Executive Compensation 132

Item 14. Principal Accounting Fees and Services 132

PART IV

Item 15. Exhibits, Financial Statement Schedules 133

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PART I

Item 1. Business.

BUSINESS

Overview

We are a clinical-stage biotechnology company advancing a pipeline of novel therapies designed to treat cancer and extend patients’ lives. Our clinical pipeline includes two clinical-stage product candidates, the CD47 blocker evorpacept and an epidermal growth factor receptor (EGFR)-targeted antibody drug candidate (ADC) ALX2004. Our lead product candidate, evorpacept, has demonstrated potential to serve as a cornerstone therapy upon which the future of immuno-oncology can be built for patients whose cancer over-expresses CD47. Evorpacept is currently being evaluated in combination with trastuzumab and chemotherapy in patients with metastatic HER2-positive breast cancer in the Phase 2 ASPEN-09-Breast clinical trial and is also being studied in clinical trials with other targeted anti-cancer antibodies. Cancer cells leverage CD47, a cell surface protein, as a “don’t eat me” signal to evade macrophage phagocytosis. We are developing evorpacept to be a next-generation checkpoint inhibitor designed to have a high affinity for CD47 and to avoid the limitations caused by hematologic toxicities inherent in other CD47 blocking approaches. Our second pipeline candidate, ALX2004, is a novel EGFR-targeted antibody-drug conjugate with a differentiated mechanism of action entered into a Phase 1 clinical trial in August 2025.

Anti-cancer agents, including many chemotherapies, other small molecules and anti-cancer antibodies, can stimulate immune cells such as macrophages to engulf and kill cancer cells, a process known as phagocytosis, by providing so-called “eat me” signals on cancer cells. In response, cancer cells frequently overexpress CD47 to counteract these “eat me” signals. As a result, high expression of CD47 on cancer cells has been associated with reduced patient survival in multiple cancers. The therapeutic blockade of CD47 in combination with an “eat me” signal enables the immune system to detect and phagocytose cancer cells. However, healthy blood cells and nearly all other cells in the body also express CD47 as a way to protect against pathologic phagocytosis by immune cells. There have been a number of approaches to blocking CD47, including monoclonal antibodies and fusion proteins that include an active Fc region. These approaches have encountered limitations, including limited dosing and therapeutic window, limited ability to combine with other anti-cancer agents, limited efficacy in solid tumors and limited indications due to patient selection, that have challenged their ability to maximize the full potential of CD47 blockade. In addition, most of these therapeutic approaches to CD47 blockade have resulted in the destruction of patients’ healthy blood cells, causing cytopenias that limit the dosing and therapeutic potential of those molecules.

ALX Oncology was founded to address fundamental challenges in blocking CD47 and to realize the full potential of this therapeutic target. Clinical data on competing CD47 blockers to date have come from molecules that incorporate an active antibody Fc region in addition to a CD47 blocking region. The Fc region provides a positive, pro-phagocytic “eat me” signal to macrophages and other cells of the immune system. Since healthy blood cells also express CD47, these competing therapeutic approaches can cause a reduction in the number of blood cells in the body, resulting in anemia, thrombocytopenia and neutropenia, which can be dangerous to patients and may limit the ability to combine these agents with other anti-cancer medicines.

Evorpacept is a next-generation CD47 blocking therapeutic that we believe has significantly enhanced properties compared to competing CD47 blocking approaches. Evorpacept is a fusion protein that combines a high-affinity CD47 binding domain with a proprietary inactivated Fc domain. The CD47 binding domain of evorpacept is an affinity enhanced extracellular domain of SIRPα, a protein found on myeloid cells such as macrophages, that is the natural receptor to CD47. We have engineered the Fc domain of evorpacept so that it does not provide a pro-phagocytic signal while still maintaining an antibody-like half-life for the molecule. We believe our inactive Fc approach improves tolerability when compared to other CD47 blocking approaches that have an Fc domain that engages activating receptors on macrophages, causing phagocytosis and death of healthy cells in addition to cancer cells.

Evorpacept’s design has several additional advantages that we believe will make it broadly applicable to treating a number of oncology indications. Due to the inactive Fc, evorpacept is specifically designed for use in combination with other anti-cancer agents that provide a positive immune-stimulating signal. We believe evorpacept has a favorable tolerability profile that may enable higher dosing levels, increased tumor penetration, and greater combination potential with other leading anti-cancer agents. Additionally, the molecular weight of evorpacept is half that of a typical antibody, therefore allowing for higher dosing (10 mg/kg of evorpacept is equivalent to 20 mg/kg of a regular antibody). The relatively smaller size of our molecule may facilitate increased penetrance into the tumor microenvironment. We believe these properties may enable evorpacept to provide superior therapeutic benefits.

Clinical data to date in evorpacept have not shown the dose-dependent hematologic toxicities characteristic of other CD47 blockers that incorporate an active Fc domain. Approximately 800 subjects have been treated with evorpacept in combination with targeted anti-cancer agents, small molecules, and checkpoint inhibitors to date. Evorpacept has not reached a maximum tolerated dose in any of the combinations evaluated to date.

We are focused on evorpacept development with the standard-of-care agents that provide a stimulatory signal to the innate immune system. We are combining evorpacept with anti-cancer targeted antibodies with an active Fc domain, where evorpacept enables the Fc-mediated antibody dependent phagocytosis that is impaired by the expression of CD47 on cancer cells.

Data from the randomized ASPEN-06 Phase 2 clinical trial supports the clinical validation of this mechanism of action. ASPEN-06 evaluates the contribution of evorpacept to HERCEPTIN® (trastuzumab) plus standard of care (CYRAMZA® (ramucirumab) + paclitaxel) (Evo-TRP), versus trastuzumab, ramucirumab, and paclitaxel (TRP) in second line or later human epidermal growth factor receptor 2 (HER2)-positive gastric/gastroesophageal junction (GEJ) cancer, where all patients had received an anti-HER2 agent in prior lines of therapy. The full data set was previously presented. Results from a pre-planned exploratory analysis were presented at the Society for Immunotherapy of Cancer (SITC) Annual Meeting:

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In a pre-planned exploratory analysis of the ASPEN-06 clinical trial in gastric cancer, CD47 overexpression was identified as a key predictive biomarker for response and durable benefit in patients with retained HER2 expression. Retained HER2 expression is defined as patients who are HER-2 positive on a tumor biopsy after receiving a HER2-targeted treatment or by HER2 amplification by circulating tumor DNA (ctDNA). The data was highlighted as part of a poster presentation at the SITC Annual Meeting in November 2025.

In patients with retained HER2-positive and CD47-high gastric cancer (n=43), Evo-TRP had a 65.0% objective response rate (ORR) versus 26.1% ORR for TRP, while patients with retained HER2-positive and CD47-low gastric cancer (n=47), Evo-TRP had a 37.5% ORR compared to 26.1% ORR for TRP.

The duration of response (DOR) was three times longer in the Evo-TRP arm relative to TRP in these patients. Evo-TRP had a median DOR (mDOR) of 25.5 months versus 8.4 months mDOR for TRP, while patients with retained HER2-positive and CD47-low gastric cancer, had an mDOR of 11.2 months for Evo-TRP compared to 12 months for TRP. Progression free survival (PFS) and overall survival (OS) data were evaluated in these patients. Treatment with Evo-TRP resulted in a median PFS (mPFS) of 18.4 months versus 7.0 months for TRP, hazard ratio (HR) of 0.39. Treatment with Evo-TRP resulted in a median OS (mOS) of 17 months versus 9.9 months for TRP, HR of 0.70.

Evorpacept has been combined in clinical trials with multiple anti-cancer antibodies in addition to trastuzumab, including the CD20-targeted antibody rituximab, the CD38-targeted antibody isatuximab-irfc, and the HER2-targeted bispecific antibody zanidatamab. Our earlier ASPEN-01 Phase 1 positive data in combination with rituximab in non-Hodgkin lymphoma (NHL); the Phase 1/2 investigator-sponsored trial (IST) of evorpacept in combination with rituximab and lenalidomide in patients with relapsed refractory B-cell NHL (R/R B-NHL) and subsequently, in patients with newly diagnosed indolent B-cell NHL (iNHL); and the Phase 1b/2 trial of evorpacept with zanidatamab in patients with HER2-positive breast cancer provide additional support for the clinical validation of this mechanism of action and support exploring combinations of evorpacept with other anti-cancer antibodies.

Our second product candidate is ALX2004, a novel EGFR-targeted ADC. ALX2004 was created from our proprietary linker-payload library and fully designed and developed in-house by our scientists. ALX2004 comprises a matuzumab-derived affinity-selected EGFR antibody backbone engineered for optimal activity as an ADC, a proprietary topoisomerase I inhibitor payload with enhanced bystander effect, and a linker with enhanced stability. EGFR is clinically validated as a therapeutic target with several U.S. Food and Drug Administration (FDA)-approved targeted antibodies and small molecules. However, there are currently no approved EGFR-targeted ADCs and early-generation attempts to develop EGFR-targeted ADCs were limited by drug design, on-target off-tumor toxicities and toxicity of older generation payloads

We are engaged in the following clinical programs, collaborations, and investigator-sponsored trials:

Evorpacept

Combination with the HER2-targeted antibody trastuzumab

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ASPEN-09-Breast – HER2+ Breast Cancer

In March 2025, we announced intent to initiate a randomized Phase 2 clinical trial evaluating evorpacept in combination with trastuzumab and chemotherapy for the treatment of patients with HER2-positive metastatic breast cancer after prior treatment with fam-trastuzumab deruxtecan-nxki.

In August 2025, we announced that based on the magnitude of benefit in patients with high CD47 expression in HER2-positive gastric cancer, the ASPEN-09-Breast study in HER2-positive breast cancer evaluating evorpacept in combination with trastuzumab and chemotherapy has been amended to a single-arm design in all previously treated HER2 positive patients and will be evaluated by CD47 expression.

In January 2026, we announced that the first patient had been dosed in the trial.

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ASPEN-06 – Gastric/GEJ Cancer

In January 2020, the FDA granted Fast Track designation for evorpacept in combination with trastuzumab, ramucirumab and paclitaxel for the treatment of patients with HER2-overexpressing advanced gastric or GEJ adenocarcinoma with disease progression on or after prior trastuzumab and fluoropyrimidine or platinum containing chemotherapy.

In January 2022, the FDA’s Office of Orphan Products Development granted Orphan Drug Designation (ODD) to evorpacept for the treatment of patients with gastric/GEJ cancer.

In March 2022, we announced the dosing of the first patient in the multi-center, international ASPEN-06 trial, a randomized Phase 2/3 trial of evorpacept in combination with trastuzumab, ramucirumab and paclitaxel for the treatment of second- and third-line advanced HER2-overexpressing gastric/GEJ cancer, where all patients had received an anti-HER2 agent in prior lines of therapy.

In June 2023, the European Commission granted ODD to evorpacept for the treatment of patients with gastric/GEJ cancer.

In October 2023, we announced positive prespecified interim Phase 2 clinical data from our ASPEN-06 clinical trial. This prespecified interim analysis reported results from 54 randomized patients with second and third line gastric/GEJ cancer, including patients previously treated with fam-trastuzumab deruxtecan-nxki and checkpoint inhibitors. A confirmed ORR of 52% was demonstrated for the Evo-TRP treatment arm compared to 22% for the TRP control arm. An mDOR was not reached for the Evo-TRP treatment arm compared to 7.4 months for the control group. The safety profile of evorpacept was consistent with previous clinical trials and was well-tolerated.

In July 2024, we announced the topline data from our ASPEN-06 Phase 2 clinical trial. This topline data reported results from 127 randomized patients with second and third line gastric/GEJ cancer and was generally well-balanced across arms based on prespecified stratification factors including line of therapy, prior ENHERTU® use, Asia region, tumor location (GC or GEJ), HER2 expression level, and having HER2-positive disease based upon a tissue biopsy after anti-HER2 treatment. A confirmed ORR of 40.3% was demonstrated for the Evo-TRP treatment arm compared to 26.6% for the TRP control arm. The mDOR was 15.7 months for the Evo-TRP treatment arm and 7.6 months for the TRP control arm in the full trial population. In patients with fresh HER2-positive biopsies (n=48), Evo-TRP demonstrated an ORR of 54.8% compared to 23.1% for the TRP control.

In January 2025, we presented updated results from the ASPEN-06 Phase 2 clinical trial in an oral presentation at the 2025 American Society of Clinical Oncology Gastrointestinal Cancers Symposium. A confirmed ORR of 41.3% was demonstrated for the Evo-TRP treatment arm compared to 26.6% for the TRP control arm in the intent-to-treat patient population. In patients with confirmed HER2-positive expression as determined by either fresh biopsy or ctDNA HER2-positivity (n=96), the addition of evorpacept to TRP resulted in a 48.9% ORR, an mDOR of 15.7 months and mPFS of 7.5 months, compared to a 24.5% ORR, an mDOR of 9.1 months and mPFS of 6.7 months in the TRP control group, with a PFS HR of 0.64.

In April 2025, we received guidance from the FDA that the ASPEN-06 Phase 2 trial data evaluating Evo-TRP was not eligible for submission for accelerated approval given the availability of ENHERTU. A Phase 3 versus ENHERTU trial would be needed to pursue a regulatory approval of evorpacept in the second-line setting for HER2-positive gastric and GEJ. Given our disciplined focus and the allocation of our resources, we will not pursue a U.S. registrational path with a Phase 3 trial in gastric cancer and will consider exploring development partnerships to advance this program in gastric cancer.

In August 2025, we announced topline results from pre-planned exploratory analysis of the ASPEN-06 trial in gastric cancer, where CD47 overexpression was identified as a key predictive biomarker for response and durable benefit.

In November 2025, we presented a pre-planned exploratory analysis of the ASPEN-06 clinical trial in gastric cancer in which CD47 overexpression was identified as a key predictive biomarker for response and durable benefit in patients with retained HER2 expression.

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In patients with retained HER2-positive and CD47-high gastric cancer (n=43), Evo-TRP had a 65.0% ORR versus 26.1% ORR for TRP, while patients with retained HER2-positive and CD47-low gastric cancer (n=47), Evo-TRP had a 37.5% ORR compared to 26.1% ORR for TRP.

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The DOR was three times longer in the Evo-TRP arm relative to TRP in these patients. Evo-TRP had an mDOR of 25.5 months versus 8.4 months mDOR for TRP, while patients with retained HER2-positive and CD47-low gastric cancer, had an mDOR of 11.2 months for Evo-TRP compared to 12 months for TRP. PFS and OS data were evaluated in these patients. Treatment with Evo-TRP resulted in an mPFS of 18.4 months versus 7.0 months for TRP, HR of 0.39. Treatment with Evo-TRP resulted in an mOS of 17 months versus 9.9 months for TRP, HR of 0.70.

Combination with the EGFR-targeted antibody cetuximab

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ASPEN-CRC – Colorectal Cancer (CRC)

In March 2025, we announced intent to initiate a Phase 1b study evaluating evorpacept in combination with the EGFR-targeted antibody cetuximab and FOLFIRI for the treatment of patients with second-line metastatic CRC.

In August 2025, we streamlined evorpacept development program to focus our resources on the ASPEN-09-Breast trial and paused the ASPEN-CRC study announced earlier in March 2025.

Collaborations and Investigator-Sponsored Trials (ISTs)

Combination with the HER2-targeted bispecific, zanidatamab, and HER2-targeted ADC, fam-trastuzumab deruxtecan-nxki

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Jazz Pharmaceuticals plc – Breast Cancer

Our collaborator, Jazz Pharmaceuticals plc (Jazz), sponsored and managed the Phase 1b/2 trial of zanidatamab, a HER2-targeted anti-cancer antibody, for the treatment of advanced HER2-expressing breast cancer and other solid tumors in combination with evorpacept (Zanidatamab Trial). We announced the dosing of the first patient in this trial in October 2021.

Our initial collaborator for the Zanidatamab Trial was Zymeworks Inc. (Zymeworks), however in a series of transactions commencing in October 2022, Jazz assumed responsibility from Zymeworks for the development and commercialization of zanidatamab in the United States, Europe, Japan and certain other territories, including responsibility for the Zanidatamab Trial.

In December 2024, Phase 1b/2 data were presented in a poster presentation at the 2024 San Antonio Breast Cancer Symposium (SABCS). The SABCS poster presentation data-cut reported on efficacy findings from all three of the part-two trial cohorts: Cohort 1 (n=21) consisted of patients with HER2-positive breast cancer who had received prior ENHERTU and also a median of six prior systemic therapies in the metastatic setting. Patients were enrolled based on local assessment of tumor samples or central assessment. Of the 21 patients enrolled in Cohort 1, nine were found to be HER2-positive based on central assessment. Cohort 2 (n=15) consisted of patients with HER2-low breast cancer who had received a median of five prior systemic therapies. Cohort 3 (n=8) consisted of patients with other HER2-expressing cancers. Patients in Cohort 1 who were HER2-positive by central assessment (n=9) showed the greatest anti-tumor activity with a confirmed ORR of 55.6% and an mPFS of 7.4 months. Overall, patients in Cohort 1 (n=21) had a confirmed ORR and mPFS of 33.3% and 3.6 months, respectively. Patients in Cohort 2 had a confirmed ORR and mPFS of 20.0% and 1.9 months, respectively. As of the August 2024 data cutoff, median follow-up was 9.6 months, with six patients still on treatment. The mDOR was not reached for Cohort 1 patients (range: 3.6-25.9 months) and was 5.5 months for Cohort 2 patients (range: 3.6-11.0 months), with responses ongoing, including the longest observed response, in each cohort. The combination therapy was well tolerated with a manageable safety profile that was consistent with prior experience of each agent.

In January 2026, we announced that an exploratory biomarker analysis showed responses in the trial were largely restricted to patients with higher CD47 expression.

Combination with the CD20-targeted antibody rituximab

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MD Anderson Cancer Center – Non-Hodgkin Lymphoma

In 2021, an IST of evorpacept was initiated in combination with rituximab and lenalidomide (R2) for the treatment of patients with indolent and aggressive NHL, sponsored by MD Anderson Cancer Center in Texas. We announced the dosing of the first patient in September 2021.

In April 2024, MD Anderson Cancer Center reported clinical data from the ongoing Phase 1/2 IST of evorpacept in combination with R2 in patients with R/R B-NHL. The new data were presented in an oral presentation at the 2024 American Association for Cancer Research (AACR) Annual Meeting. The Phase 1 part of the clinical trial enrolled a total of 20 patients with indolent (n=18) and aggressive (n=2) R/R B-NHL where all patients had received prior rituximab and 72% had received prior chemoimmunotherapy. Patients received evorpacept 30 mg/kg every two weeks (Q2W) (n=3) or 60 mg/kg every four weeks (Q4W) (n=17) in combination with standard R2 treatment. The regimen was well tolerated, and there were no dose-limiting toxicities. Patients with indolent R/R B-NHL (n=18) had a best ORR of 94% and a complete response rate of 83%. The mDOR was not reached.

In April 2025, final data for the Phase 1 portion of the MD Anderson Cancer Center IST was presented at the 2025 AACR Annual Meeting. In the total population (n=20), after a median follow-up of 28 months (95% CI, 18-28 months) the two-year PFS rate was 69% and two-year OS rate was 84%. The Phase 2 portion of the clinical trial in patients with previously untreated indolent NHL is ongoing and has completed enrollment.

In December 2025, data for the Phase 2 portion of this trial, which enrolled patients with untreated indolent NHL was presented at the 2025 American Society of Hematology Annual Meeting. The combination of evorpacept with R2 generated complete responses in 92% of patients comparing favorably to an approximate 50% historical complete response rate for R2 alone.

Combination with the CD38-targeted antibody isatuximab-irfc

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Sanofi – Multiple Myeloma

In April 2023, we announced a collaboration with Sanofi who will sponsor and manage a Phase 1/2 trial of SARCLISA® (isatuximab-irfc), an anti-cancer antibody, and dexamethasone in combination with evorpacept for the treatment of patients with relapsed or refractory multiple myeloma. We announced the dosing of the first patients in September 2024.

In August 2025, we announced that the dose escalation portion of this trial was complete and Sanofi had begun the dose optimization portion of the trial.

Based on our clinical results to date in multiple oncology indications that show encouraging anti-tumor activity and tolerability, our strategy is to pursue evorpacept as a potentially critical component of future oncology treatments in combination with anticancer antibodies.

ALX2004

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In March 2025, we filed an investigational new drug (IND) application for our first ADC program, ALX2004 and in April 2025, the FDA cleared the IND to evaluate ALX2004 in a Phase 1 clinical trial for patients with EGFR-expressing solid tumors.

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In August 2025, we announced the dosing of the first patient in the first-in-human, open-label multi-center Phase 1 clinical trial of ALX2004 for the treatment of advanced or metastatic select EGFR-expressing solid tumors.

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In January 2026, we announced that the trial had begun enrolling patients in the third dose cohort at 4 mg/kg after successfully clearing the second dose cohort. No dose-limiting toxicities were observed in the first two dose cohorts.

Our team of industry veterans plans to continue to advance a broad development plan for evorpacept that balances speed to market, scale of unmet need and existing clinical evidence for evorpacept’s combination mechanisms. Members of our management team have brought multiple drugs to the FDA approval. Our Chief Executive Officer, Jason Lettmann, brings a broad suite of expertise as an institutional healthcare investor, most recently at Lightstone Ventures, and has been involved with ALX Oncology for nearly a decade since its founding, having co-led the Company’s first institutional financing and serving as a member of the Company’s Board of Directors. He also previously served as Chief Executive Officer of Promedior, Inc. During his tenure, Promedior was acquired by Roche in 2020 for up to $1.39 billion. Our Chief Medical Officer, Barbara Klencke, M.D., brings more than 30 years of experience in patient care, academic and scientific research and clinical drug development in hematology and oncology. She has served in various executive leadership roles at a range of small, mid-sized, and large biotech companies including Sierra Oncology, Inc., Onyx Pharmaceuticals and Genentech, a member of the Roche Group. Our Chairman and founder, Corey Goodman, Ph.D., an elected member of the National Academy of Sciences, has co-founded seven biopharmaceutical companies, including Exelixis and Labrys (acquired by Teva Pharmaceuticals in 2014), and led Pfizer’s Biotherapeutics and Bioinnovation Center. Our Chief Financial Officer, Harish Shantharam, has over 20 years of experience guiding public life science companies. Most recently, he was Chief Financial Officer of Cymabay Therapeutics, and prior to this role he was Vice President and Head of Global Commercial Finance at Gilead Sciences. We have funded our operations to date primarily through the issuance and sale of our convertible preferred stock, the issuance and sale of our common stock through an initial public offering in July 2020 and a registered offering in December 2020, a term loan facility in October 2022, a registered offering in October 2023, a registered offering in February 2026, and sales under our ATM offering program.

Our Strategy

Our goal is to transform treatment options for patients with cancer by developing evorpacept as a foundational checkpoint immunotherapy.

Key elements of our strategy to support this goal include:

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Expanding the therapeutic potential of CD47 blockade by combining with anti-cancer antibodies. We believe evorpacept can overcome the limitationsof other CD47 blocking approaches.

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Developing a best- and first-in-class EGFR-targeted ADC. We believe that our differentiated design of ALX2004 based on an affinity-selected matuzumab-derived antibody can overcome the toxicity challenges that limited the therapeutic window of earlier generation EGFR-targeted ADCs.

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Continuing to develop strategic partnerships to broaden the potential impact of our current and future product candidates across patient populations. In order to advance treatment options for the most patients, we have in the past and may in the future partner with other companies with complementary resources that will maximize the value of our current and future product candidates. Such partnerships may allow us to pair evorpacept and any future product candidates with other novel agents owned fully or in part by strategic partners. Partnerships may and will also help realize the full potential of our product candidates in markets where we are unlikely to pursue development or commercialization on our own. We intend to maintain significant economic interests in our product candidates and selectively consider partnership opportunities.

Pipeline

The chart below summarizes the development status of our product candidates pipeline.

CD47 Scientific Background

Cancer immunotherapies targeting adaptive immune system checkpoints, notably those related to T cells, have transformed the standard of care in oncology across multiple cancer types. Initial clinical successes in this area have focused on stimulating the adaptive immune system. However, emerging evidence demonstrates that the innate immune system plays a crucial role in the first line of defense to eliminate transformed malignant cells and the subsequent activation of the adaptive immune system. Dendritic cells and macrophages are a type of myeloid cell and are important parts of the innate immune system. These cells eliminate cancer cells by phagocytosis and present tumor-derived antigens to T cells, a process known as cross-priming, which activates the adaptive immune system.

Cancer cells evade phagocytosis by up-regulating CD47, a transmembrane protein that mainly functions as an anti-phagocytic “don’t eat me” signal for healthy cells. CD47 interacts with its cognate receptor SIRPα, a regulatory membrane glycoprotein, that is expressed on macrophages and other myeloid cells and serves to prevent phagocytosis (“don’t eat me”) and cross-priming of the adaptive immune system (“don’t activate T cells”) when bound to CD47. By overexpressing CD47, cancer cells are able to avoid phagocytosis by macrophages and thereby evade subsequent detection by the adaptive immune system.

High CD47 expression in cancer cells has been shown to be a prognostic indicator of decreased survival in multiple oncology indications. A study published by Majeti, et al. in 2009, assessed this association in a validation cohort of 137 subjects with acute myeloid leukemia, or AML. As shown in the figure below, normal karyotype AML, or NK-AML, subjects with high levels of CD47 expression had shorter mOS of 9.1 months compared to subjects with low levels of CD47 expression who had an mOS of 22.1 months.

Evorpacept’s 1-2 Punch: Harnessing the Power of CD47 Blocking to Unmask and Directly Unleash Combination Agent on Cancer Cells

Data generated by our and other studies in the field have demonstrated that activating the immune system against cancer requires both blocking phagocytosis checkpoints and inducing pro-phagocytic signals. This can be achieved by combining CD47 blockade with either conventional chemotherapies or targeted therapies, which together promote phagocytosis by macrophages and maximize adaptive immune system response.

Therapeutic antibodies that target tumor-specific antigens, such as the HER2 receptor, also induce cellular phagocytosis. These antibodies direct macrophages to cancer cells by binding to the tumor-specific antigen and activating the macrophage by engaging the Fcγ receptors to induce phagocytosis. However, if CD47 is not blocked, the “don’t eat me” signal can limit the activity of this mechanism. CD47 blocking therapies can therefore maximize a combination agent’s clinical efficacy by overcoming the “don’t eat me” signal that is co-opted by cancer cells.

Limitations of Prior Approaches to Blocking CD47 by Companies Other than ALX Oncology

There have been a number of approaches to blocking CD47 by companies other than ALX Oncology, including monoclonal antibodies and fusion proteins that include an active Fc region. These approaches have encountered limitations that have challenged their ability to maximize the full potential of CD47 blockade.

The majority of clinical data to date from other CD47 blocking agents come from drug candidates that incorporate an active Fc region that provides an “eat” me signal to macrophage. We believe that using an active Fc region in a CD47 inhibitor limits the therapeutic window of these approaches. Given that healthy blood cells express CD47, providing a pro-phagocytic “eat me” signal while simultaneously blocking CD47, it can lead to the destruction of healthy cells. Clinical trials of CD47 blocking agents with active Fc domains have shown frequent occurrences of treatment-related cytopenias that we believe are caused by this drug design choice.

The majority of clinical data to date from other CD47 blocking agents have come from approachesthat incorporate an active Fc region that provides an “eat me” signal to macrophages. Given that healthy blood cells express CD47, the presence of an “eat me” signal coupled with CD47 binding in a single-agent leads to destruction of blood cells. This mechanism is illustrated in the figure below. The trials of these other CD47 blocking agents have resulted in frequent occurrence of treatment-related cytopenias that we believe limits the therapeutic window of these agents. In addition to limiting the dosing, cytopenias can be dangerous for patients undergoing treatment for cancer as they may already have a compromised immune system related to intensive treatment regimens and disease progression.

Advantages of ALX’s Approach to Blocking CD47

We founded ALX Oncology because we believed the limitations described above would prevent CD47 blockade from reaching its full potential as a therapy for patients with cancer. From our inception, we designed evorpacept to overcome these limitations and to maximize the utility of CD47 blockade as an effective anti-cancer therapeutic for a broad range of tumors. Specifically, we believe evorpacept may provide the following significant advantages:

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Broader therapeutic window: We believe evorpacept’s broader therapeutic window will allow for greater drug exposure than otherCD47 blocking agents potentially translating into improved efficacy across a range of cancers compared to other CD47 blocking agents. Furthermore, flexibility in dosing has allowed for several administration schedules (weekly, bi-weekly, every three weeks, monthly) that are more amenable to combination therapy dosing schedules.

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Strong potential for combination with other anti-cancer agents: CD47 blocking agents are combined with other therapeutics inorder to maximize their potential in treating patients with cancer. Unlike other CD47 blocking agents, evorpacept was specifically designed to be combined with other anti-cancer agents. We believe evorpacept’s favorable toxicity profile will enable it to be combined with a wider range of anti-cancer agents, including anti-cancer antibodies, chemotherapy and cytotoxic containing regimens, compared to other CD47 blocking agents. Furthermore, we believe that evorpacept’s inactive Fc domain will neither compete with nor potentially limit the efficacy of anti-cancer antibodies when used in combination treatments.

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Targeted immune-oncology development: Biomarker analyses completed in 2025 and 2026 from clinical trials in with evorpacept combination treatments support the use of CD47 expression as a predictive biomarker for evorpacept activity. We believe that a biomarker-driven approach incorporating CD47 expression may optimize patient selection for evorpacept combinations in subsequent development.

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Broader potential indications: We believe evorpacept’s tolerability profile will allow for broad treatment of patient populations in awide range of oncology indications. Toxicities such as cytopenias associated with other CD47 blocking agents may potentially constrain their development strategies. We believe evorpacept is well positioned to expand the therapeutic potential of CD47 blockade across a broad spectrum of hematologic and solid tumor indications.

Evorpacept

Our lead product candidate, evorpacept, is a CD47 blocking biologic in development as a combination therapy with other anti-cancer agents for treatment of various oncology indications, including gastric/GEJ, breast cancer, multiple myeloma, and NHL. We engineered evorpacept to maximize CD47 blockade and to avoid hematologic toxicities. We believe evorpacept enhances the efficacy of both anti-cancer targeted antibodies, numerous small molecule drugs and T cell checkpoint inhibitors and exhibits no dose-dependent cytopenias. Evorpacept has demonstrated encouraging clinical responses in combination with multiple anti-cancer regimens for both hematologic and solid malignancies.

Other companies have pursued CD47 blocking approaches that prioritize single-agent activity, albeit with limited success in efficacy and significant toxicity. Rather than designing a molecule for monotherapy activity that has been associated with cytopenias, we designed evorpacept for use in combination with anti-cancer agents. Our product candidate exclusively blocks the “don’t eat me” pathway. A combination anti-cancer agent provides a specific pro-phagocytic signal on cancer cells. This approach may both increase the specificity to cancer cells and avoid dose-dependent destruction of healthy blood cells.

Fusion Protein Design

Evorpacept is a fusion protein designed to provide a high CD47 blocking potency while potentially eliminating any associated toxicities. Our fusion protein comprises an engineered CD47-binding domain of SIRPα that has been genetically linked to a modified human immunoglobulin-derived Fc domain that does not bind to Fcγ receptors. We engineered evorpacept in two important ways:

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We mutated the binding domain to optimize CD47 affinity. Evorpacept binding domain demonstrates an affinity that is over 3,000 times stronger than wildtype SIRPα.

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We fused the CD47-binding region of SIRPα to an inactive Fc domain. Incorporating an inactive Fc domain was intended to eliminate single-agent activation of macrophages while still maintaining an antibody-like pharmacokinetic, or PK, profile.

The successful design of evorpacept required in-house generation of approximately 280 different protein constructs to thoroughly evaluate and optimize the impact of differing designs on multiple important evaluation criteria.

In order to optimize evorpacept’s properties we conducted the following processes:

Design of the high-affinity CD47 binding domain:

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Optimization of binding affinity for human CD47;

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Optimization of cross-reactivity to rodent and monkey CD47 to enable key translational experiments; and

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Elimination of partially glycosylated sites in SIRPα to remove heterogeneity and enable consistent manufacturing.

Design of the optimal fusion combination for PK extension:

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Selection of an immunoglobulin isotype to prevent hemagglutination; and

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Selection of mutations to immunoglobulin G1, or IgG1, to functionally eliminate Fcγ binding and avoid associated cytopenias while maintaining neonatal Fc receptor binding that enables antibody-like PK.

As illustrated in the figure below, evorpacept comprises:

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A SIRPα binding domain optimized to bind to CD47 with high affinity at a picomolar level; and

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An inactive Fc domain that reduces cytopenias while preserving the desired PK properties of antibodies with an active Fc domain.

The resulting fusion protein has approximately one-half the molecular weight of a typical antibody. Evorpacept’s lower molecular weight enables it to deliver the molar equivalent of an antibody at one half the dose. For example, a 10mg/kg of evorpacept is equivalent to 20 mg/kg of a regular antibody. Evorpacept’s lower molecular weight may also facilitate increased solid tumor penetration and provide greater potency within the tumor microenvironment. Furthermore, evorpacept can be efficiently and consistently produced at high yield at commercial scale utilizing standard monoclonal antibody manufacturing techniques. We believe evorpacept’s differentiated properties potentially overcome the limitations of other CD47 blocking agents and may have utility as a combination agent in oncology.

Our lead candidate, evorpacept, is a fusion protein that potently and selectively binds CD47 to block the SIRPα interaction.

Pre-Clinical Differentiation

Our preclinical studies of evorpacept support a target product profile of favorable tolerability, the ability to be dosed at high levels and increased anti-tumor activity as compared to other CD47 blocking agents. These data include the following:

Lack of hematologic side effects

Our preclinical data demonstrate that CD47 blocking agents with an active Fc domain directly cause adverse hematologic side effects. To support this hypothesis, we engineered a fusion protein with a SIRPα CD47-binding domain identical to evorpacept’s binding domain but fused to an active, wild-type IgG1 Fc domain, ALX377. We administered 30 mg/kg evorpacept and 30 mg/kg ALX377 in mouse models and measured red blood cell, or RBC, platelet and white blood cell (lymphocyte, monocytes and granulocytes) counts. As shown in the figure below, mice treated with evorpacept having an inactive Fc domain showed blood count levels that were similar to the pre-dose baseline. In contrast, mice treated with ALX377 having an active Fc domain showed average decreases of 34% in RBC count, 70% in platelet count and 67% in white blood cell count three days post-dosing as compared to baseline counts.

The inactive Fc domain on evorpacept is responsible for improved hematologic tolerability in preclinical models.

In vitro and in vivo toxicology studies in monkeys show that evorpacept was well-tolerated at intravenous doses of up to 100 mg/kg/week in the 1-month study and up to 30 mg/kg every other week in the 3-month study with no target organ toxicity or toxicity related to the exaggerated pharmacology of evorpacept. Together, these preclinical studies demonstrate that inactivation of the Fc domain of evorpacept avoids adverse effects on normal blood cells seen on other CD47 blocking agents with an active Fc domain. They also support our expectation that evorpacept’s lack of overlapping toxicities with other anti-cancer therapies may result in fewer adverse outcomes in the clinic when combined with these therapies than combinations with conventional CD47 blocking agents.

Evorpacept elicits superior phagocytosis in combination with anti-cancer antibodies

The inactive Fc of evorpacept does not compete with the active Fc domain of other therapeutic antibodies for binding with Fcγ receptors on effector cells of the immune system. This fact, coupled with the high-affinity CD47 binding of our agent, results in enhanced phagocytosis from evorpacept in combination with other anti-cancer antibodies to a greater extent than other CD47 blockers. We believe this will allow us to explore evorpacept in combination with a higher number of leading anti-cancer antibodies compared to other CD47 blocking agents in both hematologic malignancies and solid tumors. In order to investigate the potential effects of the Fc domain and CD47 binding affinity on phagocytic activity, we produced two CD47 blocking agents with either an IgG4 or IgG1 active Fc domain, based on published sequences from two other clinical CD47 blockade programs. We combined these agents and evorpacept with cetuximab, an epidermal growth factor receptor, or EGFR, inhibitor that is the FDA approved for several solid tumors, to assess phagocytic activity as compared to single-agent cetuximab. Both cetuximab and the active Fc domain of a CD47 blocking agent bind to the same cell surface Fcγ receptors on a macrophage, potentially creating competition. IgG1 binds to receptors with higher affinity than IgG4 does, and evorpacept’s inactive Fc does not bind. This experiment shows that CD47 blocking agents with active Fc domains and lower affinity, combined with cetuximab result in lower phagocytic activity from macrophages as compared to evorpacept with cetuximab. This experiment suggests evorpacept, the only clinical CD47 blocking agent with an inactive Fc domain and high-affinity CD47 binding, may be unique in its anti-tumor activity when combined with anti-tumor antibodies.

Evorpacept has shown superior antibody-dependent cellular phagocytosis, or ADCP, of solid tumor cells compared to CD47 blockers with an active Fc domain and lower CD47 affinity when combined with an anti-tumor antibody.

ALX2004 scientific background: ADC target selection

EGFR is a transmembrane protein in the ERBB family of receptor tyrosine kinases that consists of EGFR (HER1), HER2, HER3, and HER4 and is over expressed in many cancer types. It is also expressed in normal tissues, but often to a lesser degree. It plays a prominent role in tumor initiation and growth through dysregulation of cell proliferation, differentiation, metabolism, and cell death. Cancers survive and proliferate through aberrant overexpression of and mutational activation of EGFR. Therefore, EGFR has been an attractive target for cancer therapies.

EGFR is a commercially validated antibody target with multiple FDA approved EGFR-targeted antibodies include cetuximab (ERBITUX®) and panitumumab (VECTIBIX®) in addition to several small molecules. However, there are no FDA approved EGFR-targeted ADCs. Earlier generation attempts at anti-EGFR ADCs failed to find a therapeutic window.

EGFR gene expression levels from RNA sequencing. ALX2004 Phase 1 trial includes patients with colorectal cancer, esophageal carcinoma, head and neck squamous cell carcinoma, and lung cancer. Source: GEPIA http://gepia.cancer-pku.cn/

ALX2004 design process and drug candidate selection

ALX2004 was developed in-house by ALX Oncology protein engineers and designed to maximize potential success based on a rigorous optimization and drug candidate selection process. The ALX2004 linker-payload was selected from a starting point of 600 payloads designed in silico with 60 topoisomerase I inhibitor payloads subsequently synthesized and tested in lab, which are now part of the ALX ADC library. From this payload library, we generated and tested 70 ADCs across 3 solid tumor antigen targets and 2 ultimately tested in rat and non-human primate (NHP) toxicity studies leading to the final linker and Top1i payload selection for ALX2004.

The anti-EGFR antibody for ALX2004 was also selected after a rigorous development process. Six different anti-EGFR antibodies with varying EGFR binding epitopes and binding affinities were tested. The goal of this process was to select an antibody that minimized off-tumor EGFR-related toxicity while maintaining an active therapeutic window. ALX2004 was the culmination of this development process. As part of this process, we also generated a proprietary library of potential ADC payloads for future drug candidates.

ALX2004 is designed using lessons learned from past attempts at EGFR-targeted ADCs

Several EGFR-targeted ADCs have previously entered clinical trials including depatuxizumab mafadotin, serclutamab talirine, and AMG595. Depatuxizumab mafadotin used a monomethyl auristatin F (MMAF) payload. Serclutamab talirine used a pyrrolobenzodiazapene (PBD) payload. AMG595 used a maytansinoid (DM1) payload. We believe the primary reason these drugs did not reach FDA approval was due to the toxicity profiles of these payload classes and not because they were EGFR-targeted. Consequently, we designed ALX2004 with a topoisomerase 1 inhibitor payload.

We further aimed to maximize the likelihood of technical success by using a matuzumab-derived anti-EGFR antibody with an affinity selected to minimize on-target, off-tumor skin toxicity. We believe that using a matuzumab-derived antibody increases the likelihood of finding a clinically meaningful therapeutic window. Additionally, matuzumab binds an EGFR epitope that is distinct from other FDA-approved antibodies. Consequently, patients who developed resistance to cetuximab or panitumumab due to mutations in the EGFR extracellular domain, may still be sensitive to ALX2004. This is important for establishing activity during early stage trials in EGFR-expressing tumors where patients may have been previously treated with EGFR-targeted antibodies.

ALX2004 linker payload selection: 600 payloads designed with 60 payloads synthesized and screened

We first designed 600 Top1i payload candidates in silico from which we synthesized and conducted in vitro screening for over 60 novel ALX Top1i payloads across 8 tumor cell lines each and benchmarked potentcy against two Top1i payloads from approved ADCs – SN38 (payload for TRODELVY®) and deruxtecan (payload for ENHERTU®).

Next, 14 payload candidates were selected for testing as full ADCs based on their cytotoxicity and membrane permeability. Each payload was conjugated to ALX’s proprietary linker, tested for in vitro activity against 6 tumor cell lines, and benchmarked against the deruxtecan payload. The ALX2004 linker-payload was selected for its consistent potency across these models, relatively high membrane permeability, and comparable activity to the deruxtecan benchmark.

Additionally, this process generated a library of ALX proprietary Top1i payload candidates with a range of potencies and varying properties such as ability to permeate cell membranes as a free payload. Relatively high membrane permeability may improve bystander effect cell killing; whereas low permeability may greatly decrease or eliminate the bystander effect.

Cytotoxicity EC50(nM) of synthesized TOP1i payloads robustly tested in eight cancer cell lines and compared to SN-38 (govitecan payload) and DXd (deruxtecan payload). Each x-axis tick corresponds to a payload. The arrow marks ALX2004_payload. The dashed lines show the average EC50 (nM) of DXd across cell lines.

ALX2004 shows improved stability compared to deruxtecan benchmark

The ALX2004 linker was designed to improve stability of the ADC in circulation in order to minimize off-tumor linker-payload release. Enhanced stability should both decrease off tumor toxicity and increase the amount of payload that is being delivered to the tumor. Deconjugation of the linker payloads from their antibody in circulation remains a challenge and may lead to increased toxicity.

In order to benchmark our lead linker-payload candidate’s stability, we conducted a head to head comparison against deruxtecan in non-human primates. We conjugated the ALX2004 linker-payload to trastuzumab (a HER2-targeted antibody) in order to make a direct comparison to trastuzumab deruxtecan. We then compared drug antibody ratios, or DAR, of the drugs in circulation over time. An ADC’s DAR is a measurement of how many payloads are conjugated to the antibody. Decreasing DAR over time in circulation indicates that payload has deconjugated from the antibody in a non-targeted way thereby potentially increasing toxicity.

The ALX linker-payload demonstrated superior stability and maintained a higher conjugation level, as indicated by DAR, in circulation over time. These data suggest that ALX2004 may deliver more payload to tumors while limiting exposure to healthy tissues due to decrease in linker-payload deconjugation.

Improved DAR stability of ALX2004_linkerpayload compared to deruxtecan. Graph shows DAR of two ADCs: trastuzumab conjugated to ALX2004_linkerpayload (DAR ~8) and trastuzumab conjugated to deruxtecan (DAR ~8), as a function of time in non-human primate (NHP) dosed at 30 mg/kg (n=2 per group). DAR was analyzed using reduced middle-down RP-LCMS.

ALX2004 shows comparable direct cell killing and improved bystander effect relative to deruxtecan comparator

ALX2004 was tested in several EGFR-expressing mouse models against a deruxtecan-based ADC comparator generated in-house. These tests showed that ALX2004 matched or exceeded the activity of the deruxtecan comparator ADC both in terms of direct cell killing and bystander effect.

The bystander effect is thought to be an important mechanism of cell killing in solid tumors for ADCs. The bystander effect begins when an ADC binds to its target on the cell surface and is internalized into the cell. Payload is then released within the target-expressing cell which results in the direct killing of the target-expressing cell. For some ADCs, the released payloads are then able to permeate into neighboring cells regardless of whether or not target is expressed killing those neighboring cells as well. In heterogenous solid tumors, it is potentially an important mechanism for tumor control as it results in the killing of both target expressing tumor cells and non-target expressing tumor cells in the tumor microenvironment.

We selected the ALX2004 payload from the over 60 we synthesized in part because we believed it could have enhanced bystander effect relative to deruxtecan due to the membrane permeability testing we conducted. In order to compare ALX2004’s direct cell killing and bystander effect to deruxtecan, we synthesized an ADC using the ALX2004 anti-EGFR antibody conjugated to the deruxtecan linker payload.

First, we tested the ALX2004 and deruxtecan comparator ADC in a cell-based bystander assay. As shown below, ALX2004 had comparable direct cytotoxicity (A) and improved bystander killing (B).

We then compared the potency of ALX2004 in several EGFR-expressing mouse models (A below) and a bystander effect model (B below) to the deruxtecan based comparator ADC.

Across multiple mouse models with varying levels of EGFR expression level, ALX2004 demonstrated equivalent or superior tumor eradication as shown by the percent of mice in which tumors were completely eradicated. ALX2004 outperformed the deruxtecan comparator in a bystander effect model that contained both EGFR high expressing and EGFR ultra-low expressing cancer cells.

Percent of tumor-free mice in CDX models dosed with ALX2004 or ALX2004_mAb-deruxtecan (ADC composed of ALX2004’s antibody conjugated to deruxtecan) (both ADCs, DAR ~8). (A) MDA-MB-468 (3 mg/kg, 1 dose), FaDu (1 mg/kg, 3 doses, Q1W), NCI-H292 (3 mg/kg, 3 doses, Q1W), (B) Bystander effect CDX model composed of 1:1 NCI-H292 cells (~80,000 EGFR/cell surface) and SW620 cells (~2000 EGFR/cell surface) dosed 3 mg/kg, 3 doses, Q1W. NOD SCID mice, n=5 per group.

ALX2004 showed tumor suppression across a range of cancer types and target expression levels

We tested ALX2004 in vivo anti-tumor activity in mouse models representing a range of commercially relevant EGFR-expressing tumor types, EGFR-expression levels, and common mutations. ALX2004 inhibited tumor growth in non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), CRC, triple negative breast cancer (TNBC), and pancreatic ductal adenocarcinoma (PDAC) mouse models. These models also show ALX2004’s activity in models harboring KRAS, BRAF, and P53 mutations. Importantly, tumor growth inhibition was seen at all levels of EGFR-target expression ranging from 12,000 units/cell surface to over 400,000 units/cell surface.

ALX2004 has inhibited tumor growth in vivo. Tumor volume (mm3) after IV administration of a single dose or three doses of ALX2004 at indicated dose levels (mg/kg) and dosing frequencies in CDX mouse models of NSCLC (A-D) and other EGFR-expressing tumors (E-J): (A) HCC827, (B) NCI-H1975, (C) NCI-H292, (D) A549, (E) FaDu, (F) COLO205, (G) HCT116, (H) MDA-MB-468, (I) CFPAC-1, (J) PDOX model CRC22420. Dosing frequency indicated by black arrows. Data represented as mean ± SEM, (A-B, E-J) n=12 per group, NU/NU mice, (C-D) n=5 per group, NOD SCID mice. (K) Representative IHC staining of EGFR in PDOX tissue. wt refers to EGFR wild-type tyrosine kinase domain.

GLP toxicity study in non-human primates supports ALX2004 design for improved therapeutic window

The toxicity and toxicokinetic profile of ALX2004 was evaluated in a 6-week repeat-dose (Q3W dosing) GLP toxicity study in monkeys, at doses of 5, 10, and 20 mg/kg. No dose-limiting major target organ toxicity, including on-target toxicity (i.e., skin or other EGFR-expressing cells), was observed. Furthermore, there was no evidence of ILD which is a concern for some Top1i-based ADCs. The no observable adverse event level (NOAEL) was 10 mg/kg and the highest non-severely toxic dose (HNSTD) was 20 mg/kg. All findings were minimal to moderate and fully recoverable.

These findings in addition to the rest of the preclinical data package for ALX2004 allowed us to start at a 1 mg/kg dose level in ALX2004’s first-in-human clinical trial.

ALX2004 first-in-human study is in patients with EGFR-expressing solid tumors

We designed ALX2004’s Phase 1 study to maximize both efficiency and the probability of technical success by selecting tumor types with the following characteristics:

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EGFR expression

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Sensitivity to topoisomerase I inhibitors

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Sensitivity to EGFR-targeted antibodies

By evaluating tumor types on these criteria, we selected NSCLC, HNSCC, CRC, and esophageal squamous cell carcinoma (ESCC) as eligible tumor types for the dose finding portion of the Phase 1 trial. Importantly, this group of tumor types represents a significant unmet need with over 450,000 patients living with these tumors in the metastatic stage in the US alone.

The study consists of a Phase 1a dose escalation portion followed by optional dose exploration, and a Phase 1b dose expansion. The dose escalation portion of the trial is enrolling patients with previously treated NSCLC, HNSCC, CRC, and ESCC.

The first patient was dosed in this trial in August 2025. As of January 2026, the first two dose levels had been cleared with no dose-limiting toxicities. Initial safety data is anticipated in the first half of 2026.

Licensing and Intellectual Property

Our commercial success depends in part on our ability to obtain and maintain proprietary protection for our current and future product candidates, novel discoveries, product development technologies and knowhow and to operate without infringing on the proprietary rights of others. We seek to protect our proprietary position by, among other methods, filing or in-licensing U.S. and foreign patents and patent applications related to technology, inventions and improvements that are important to the development and implementation of our business. Our patent portfolio is intended to cover our product candidates and related components, their methods of use and processes for their manufacture and any other inventions that are commercially important to our business. We also rely on trademarks, trade secrets, know-how, continuing technological innovation and confidential information to develop and maintain our proprietary position.

As of January 4, 2026, we own 11 issued U.S. patents, 86 foreign issued patents, 9 pending U.S. nonprovisional patent applications and a portfolio of national patent application filings in a variety of non-U.S. jurisdictions, including Europe, Hong Kong, Brazil, Mexico, New Zealand, Japan, Australia, Canada, China, India, Israel, Republic of Korea, Singapore, Taiwan and Russia. Of these patents and patent applications, the following relate to evorpacept: seven issued U.S. patents, six pending U.S. nonprovisional patent applications, and a portfolio of granted and pending patent filings in a variety of non-U.S. jurisdictions, including Europe, Hong Kong, Brazil, Mexico, New Zealand, Japan, Australia, Canada, China, India, Israel, Republic of Korea, Singapore and Russia. The following relate to antibody shielding technology and exatecan derivatives: one issued U.S. patent, three pending U.S. nonprovisional patent applications, and 49 pending foreign patent applications.

The term of individual patents depends upon the legal term for patents in the countries in which they are granted. Our 11 U.S. issued patents and, if issued as U.S. patents, our 8 U.S. nonprovisional patent applications are expected to expire between August 2036 and November 2043 excluding any additional term for patent term adjustments or patent term extensions, with an expiration of between August 2036 and May 2043 with respect to our patent and patent applications related to evorpacept, excluding any additional term for patent term extensions.

We obtained a worldwide, royalty-bearing, sublicensable license from the Board of Trustees of the Leland Stanford Junior University, or Stanford, under certain patents relating to high-affinity SIRPα variant polypeptides, to develop, manufacture and commercialize products for use in certain licensed fields, the scope of which would include the application of the licensed intellectual property in oncology. For more information regarding our license agreement with Stanford, please see “—Exclusive (Equity) Agreement with Stanford University.”

The patent portfolio we have exclusively licensed from Stanford contains patent families relating to high-affinity SIRPα variant polypeptides, which includes three issued patents in the U.S. and one each in Australia, Canada, China, Europe, Hong Kong and four in Japan. The European patent has been validated as national patents in 37 different European countries. The patent family includes one pending patent application in each of U.S., Europe, and China and two pending patent applications in Hong Kong. These patents and patent applications are subject to retained rights by Stanford to allow academic and nonprofit research institutions to practice the licensed technology and patents for noncommercial purposes. In addition, these patents are subject to certain pre-existing rights that Stanford has granted to two third parties. These patents are expected to expire in 2033 excluding any extension of patent term that may be available.

We are aware of a European patent (EP 2 429 574) owned by UHN and The Hospital for Sick Children that relates to the treatment of hematologic cancers with polypeptides comprising soluble human SIRPα, or a CD47-binding fragment thereof. This patent was subject to European Patent Office opposition proceedings, which resulted in the patent being upheld in amended form.

Additionally, we are aware of a second European Patent (EP 2 995 315), a divisional of European patent (EP 2 429 574), granted to UHN and The Hospital for Sick Children. This patent relates to the eradication of hematological CD47+ cancer cells and tumors with polypeptides comprising soluble human SIRPα, or a CD47-binding fragment thereof. This patent was upheld as granted by the European Patent Office Opposition Division on November 28, 2025. This decision is currently under appeal.

The patent claims of both EP 2 429 574 and EP 2 995 315 could potentially limit our ability to pursue evorpacept in certain indications in certain territories in the EU in the future unless we obtain a license under these patents, these patents are determined to be invalid or unenforceable by the European Patent Office or a national court in one or more relevant territories, these patents are revoked or otherwise limited by the European Patent Office or a national court, or until these patents expire. A license may however not be available on commercially reasonable terms or at all. The U.S. counterpart to EP 2 429 574 was granted in 2021 as US patent 10,907,209. However, we believe that we do not infringe claims listed in this U.S. patent. Further, with respect to the development of our ALX2004 program, many companies have filed, and continue to file, patent applications related to antibody drug conjugates and components thereof that are similar to our approach. As the biotechnology industry expands and more patents are issued, the risk increases that we may be subject to claims of infringement of the patent rights of third parties. There is no assurance that there are not third-party patents or patent applications of which we are aware, but which we do not believe are relevant to our business, which may, nonetheless, ultimately be found to limit our ability to make, use, sell, offer for sale or import our future approved products, if any, or impair our competitive position.

For more information regarding the risks related to our intellectual property, including the above referenced intellectual property proceedings, see “Risk Factors—Risks Related to Our Intellectual Property.”

Exclusive (Equity) Agreement with Stanford University

In March 2015, we entered into a license agreement, or the Stanford Agreement, with The Board of Trustees of the Leland Stanford Junior University under which we obtained a worldwide, royalty-bearing, sublicensable license under certain patents relating to our current product candidates, to develop, manufacture and commercialize products for use in certain licensed fields, the scope of which would include the application of the licensed intellectual property in oncology. The license granted to us in the Stanford Agreement includes an exclusive grant, subject to certain pre-existing non-exclusive or exclusive rights that Stanford retained for grant to third parties with respect to certain categories of the licensed patents in certain fields of use and retained rights by Stanford and all other nonprofit institutions to use and practice the licensed patents and technology for internal research and other nonprofit purposes. The license granted to us in the Stanford Agreement also includes non-exclusive grants to certain Stanford patents.

In consideration for the rights granted to us under the Stanford Agreement, we paid Stanford a nonrefundable license royalty and reimbursed Stanford for past patent expenses, together totaling less than $0.1 million, and granted Stanford a specified number of our common stock. In addition, we are obligated to pay Stanford ongoing patent expenses and an annual license maintenance fee, which are nominal and will be creditable against any royalties payable to Stanford in the applicable year. We are required to make milestone payments up to an aggregate of $5.0 million in respect of a specified number of licensed products that successfully satisfy certain clinical and regulatory milestones. We recorded the first milestone payment of $0.2 million during the year ended December 31, 2021. There have been no milestones met during the year ended December 31, 2025. We also agreed to pay Stanford tiered royalties on a specified percentage of net sales made by us, our affiliates and our sublicensees of licensed products at rates ranging within low single-digit percentages, subject to certain reductions and offsets. Our license, on a licensed product-by-licensed product and country-by-country basis, shall become royalty-free and fully paid-up upon the later of the date on which the last valid claim included in the exclusively or non-exclusively licensed patents expires and ten years after the first commercial sale of the licensed product in such country.

We may terminate the Stanford Agreement, on a licensed product-by-licensed product basis, at any time for any reason by providing at least 60 days’ written notice to Stanford. Stanford may terminate the Stanford Agreement if we are in breach of any provision of the Stanford Agreement and fail to remedy such breach within 60 days after written notice of such breach by Stanford. In addition, Stanford has the right to terminate the Stanford Agreement, on a licensed product-by-licensed product basis, if we are not

diligently developing and commercializing such licensed product under certain conditions or if we fail to achieve specified development milestones for such licensed product by certain dates, subject to our extension rights.

Other Third-Party Agreements

We have entered into license agreements with third parties related to the development and commercialization of our product candidates, including evorpacept, and SIRPα antibodies which we are exploring in our research program. In consideration of the foregoing, we have agreed to customary payment terms in these agreements, including certain milestone payments upon the achievement of clinical and commercial milestones and low single-digit royalties. See further details in Note 13 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.

Commercialization

We intend to retain significant development and commercial rights to our product candidates and, if marketing approval is obtained, to commercialize our product candidates on our own, or potentially with a partner, in the United States and other regions. We currently have no sales, marketing or commercial product distribution capabilities and have no experience as a company commercializing products. We intend to build the necessary infrastructure and capabilities over time for the United States, and potentially other regions, following further advancement of our product candidates. Clinical data, the size of the addressable patient population, the size of the commercial infrastructure and manufacturing needs may all influence or alter our commercialization plans.

Manufacturing and Supply

We do not own or operate and do not intend to establish our own manufacturing facilities. We rely on, and will continue to rely on, CMOs for both drug substance and drug product. Evorpacept and ALX2004 bulk drug substance and finished drug product are produced in accordance with current good manufacturing practices, or cGMPs.

Our existing supply of evorpacept and ALX2004 is sufficient to complete our clinical trials through the first quarter of 2026. We plan to manufacture additional supplies with our existing CMOs to produce evorpacept and ALX2004 drug product sufficient to complete the ongoing and planned clinical trials described in this document. We first entered into an engagement with KBI Biopharma, Inc. in 2015 for evorpacept analytical method development, formulation development, bulk drug manufacturing, release and stability testing. We first entered into an engagement with Patheon Biologics LLC in 2022 for evorpacept bulk drug manufacturing and release testing. We first entered into a drug product manufacturing agreement with Lyophilization Services of New England, Inc. (now PCI Pharma Services) in 2016 for evorpacept drug product used in clinical trials. We subsequently entered into a drug product manufacturing agreement with Patheon UK Limited in 2022 for drug product production of evorpacept drug product used in clinical trials. We first entered into an engagement with WuXi Biologics and WuXi XDC in 2023 for ALX2004 analytical method development, formulation development, bulk drug manufacturing, drug product manufacturing, release and stability testing, used in clinical trials.

Competition

The development and commercialization of new product candidates is highly competitive. We face competition with respect to evorpacept and ALX2004, and will face competition with respect to any product candidates that we may seek to develop or commercialize in the future, from major pharmaceutical, specialty pharmaceutical and biotechnology companies among others. We compete in the segments of the pharmaceutical, biotechnology and other related markets that develop immune-oncology therapies for the treatment of cancer. There are other companies working to develop immuno-oncology therapies for the treatment of cancer including divisions of large pharmaceutical and biotechnology companies of various sizes. Newly approved therapeutics could change the treatment paradigm or standard of care, which could negatively impact the design of our clinical trials and the prospects of our product candidates.

Some of these competitive products and therapies are based on scientific approaches that are the same as or similar to our approach, including with respect to the targeting of the CD47 pathway, targeting EGFR as an ADC target and others are based on entirely different approaches. We are aware that Adagene, Akesobio, Bio-Thera Solutions, Boehringer Ingelheim, Bristol Myers Squibb, Byondis, Centessa, Conjupro Biotherapeutics, CTTQ (SinoBiological), Daiichi Sankyo, Exelixis, GenSci, Gilead Sciences (through its acquisition of Forty Seven), Hanchor Bio, Hisun, Hutchmed, I-Mab, Ichnos, ImmuneOncia Therapeutics, ImmuneOnco Biopharma, Innovent, Kahr, LaNova, Lightchain Bioscience, Mabwell Therapeutics, Mabworks, Novimmune, OSE Immunotherapeutics, Pfizer (through its acquisition of Trillium Therapeutics), Phanes, Pyxis Oncology (through its acquisition of Apexigen), Shandong New Time, Shattuck Labs, Sorrento Therapeutics, Sumgen, SunHo Pharmaceutical, TG Therapeutics, Waterstone, and Zai Lab, among others, are developing or have begun development of drugs targeting the CD47 pathway that may have utility for the treatment of indications that we are targeting. We are also aware that AstraZeneca, BioNTech, Bristol Myers Squibb with Systimmune, CSPC, and Henlius, among others, are developing or have begun development of antibody drug conjugates targeting EGFR. Potential competitors also include academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization.

There are already a variety of available drug therapies marketed for cancer and some of the currently approved drug therapies are branded and subject to patent protection and others are available on a generic basis. Many of these approved drugs are well established therapies and are widely accepted by physicians, patients and third-party payors. Insurers and other third-party payors may also encourage the use of generic products. We expect that if evorpacept, ALX2004 and/or any of our other future product candidates are approved, they will be priced at a significant premium over competitive generic products. This may make it difficult for us to achieve our business strategy of using our product candidates in combination with existing therapies or replacing existing therapies with our product candidates.

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

We could see a reduction or elimination of our commercial opportunity if our competitors develop and commercialize products that are safer, more effective, more convenient or less expensive than any products that we or our collaborators may develop. Our competitors also may obtain FDA or foreign 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. The key competitive factors affecting the success of all our product candidates, if approved, are likely to be their efficacy, safety, convenience, price, the level of biosimilar or generic competition and the availability of reimbursement from government and other third-party payors. The inability to compete with existing or subsequently introduced drugs would harm our business, financial condition and results of operations.

Government Regulation

In the United States, the FDA, regulates biologic products under the Food, Drug, and Cosmetic Act, or FDCA, and Public Health Service Act, or PHSA. Biologic products and substances are subject to other federal, state and local statutes and regulations. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or post-market may subject an applicant to administrative or judicial sanctions. These sanctions could include, among other actions, the FDA’s refusal to approve pending applications, withdrawal of an approval, a clinical hold, untitled or warning letters, product recalls or market withdrawals, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement and civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.

The FDA and other regulatory authorities at federal, state and local levels, as well as in foreign countries, extensively regulate, among other things, the research, development, testing, manufacture, quality control, import, export, safety, effectiveness, labeling, packaging, storage, distribution, record keeping, approval, advertising, promotion, marketing, post-approval monitoring and post approval reporting of biologics such as those we are developing. We, along with third-party contractors, will be required to navigate the various preclinical, clinical and commercial approval requirements of the governing regulatory agencies of the countries in which we wish to conduct studies or seek approval or licensure of our product candidates.

U.S. Biologics Regulation

Any future product candidates must be approved by the FDA through the BLA process before they may be legally marketed in the United States.

The process generally involves the following:

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Completion of extensive preclinical laboratory tests and animal studies performed in accordance with the FDA’s current Good Laboratory Practices, or GLP, regulation.

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Submission to the FDA of an investigational new drug, or IND, application, which must become effective before clinical trials may begin and must be updated annually or when significant changes are made.

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Approval by an independent institutional review board, or IRB, or ethics committee at each clinical site before the trial is commenced.

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Performance of adequate and well-controlled human clinical trials in accordance with the applicable IND regulations, good clinical practice, or GCP, requirements to establish the safety and effectiveness of the proposed biologic product candidate for its intended purpose.

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Compliance with PREA, BPCA and FDARA regarding development of certain molecularly targeted oncology drugs for pediatric use.

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Preparation of and submission to the FDA of a BLA.

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A determination by the FDA within 60 days of its receipt of a BLA to file the application for review.

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Satisfactory completion of any FDA audit of selected clinical trial sites that generated the data in support of the BLA.

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Satisfactory completion of an FDA pre-approval inspection of the manufacturing facility or facilities at which the proposed product is produced to assess compliance with cGMPs, and to assure that the facilities, methods and controls are adequate to preserve the biological product’s continued safety, purity and potency.

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Satisfactory completion of an FDA Advisory Committee review, if applicable.

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FDA review and approval of a BLA to permit commercial marketing of the product for particular indications for use in the United States.

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If necessary, FDA review and approval of the combination partner NDA/BLA to address any cross-labeling requirements to permit commercial marketing of the combination product for the particular indications for use in the United States.

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Compliance with any post-approval requirements, including the potential requirement to implement a Risk Evaluation and Mitigation Strategy, or REMS, and the potential requirement to conduct post-approval studies.

Preclinical and Clinical Development

The data required to support a BLA are generated in two distinct developmental stages: preclinical and clinical. The preclinical and clinical testing and approval process require substantial time, effort and financial resources, and we cannot be certain that any approvals for any future product candidates will be granted on a timely basis, or at all.

The preclinical developmental stage generally involves laboratory evaluations of product chemistry, formulation and stability, as well as studies to evaluate toxicity in animals, including pharmacology, PK, toxicokinetic and metabolism studies, that support subsequent clinical testing in humans. The sponsor must submit the results of the preclinical studies, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. Preclinical studies include laboratory evaluation of product chemistry and formulation, as well as in vitro and animal studies to assess the potential for adverse events and in some cases to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations for safety/toxicology studies.

Prior to beginning the first clinical trial with a product candidate, we must submit an IND to the FDA. An IND is a request for authorization from the FDA to administer an investigational new biopharmaceutical product to humans.

The central focus of an IND submission is on the general investigational plan and the protocol(s) for clinical trials. An IND must become effective before human clinical trials may begin. The IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises any concerns or questions about the proposed clinical trial(s) and places the trial(s) on clinical hold. In such a case, the IND may be placed on clinical hold and the IND sponsor and the FDA must resolve any outstanding concerns or questions before the clinical trial can begin. Submission of an IND therefore may or may not result in FDA authorization to begin a clinical trial.

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCPs, which include the requirement that all research subjects provide their informed consent for their participation in any clinical trial. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria and the parameters to be used to monitor subject safety and assess efficacy. Each protocol, and any subsequent amendments to the protocol, must be submitted to the FDA as part of the IND. Furthermore, an independent IRB for each site proposing to conduct the clinical trial must review and approve the plan for any clinical trial and its informed consent form before the clinical trial begins at that site and must monitor the trial until completed. Regulatory authorities, the IRB, or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the subjects are being exposed to an unacceptable health risk or that the trial is unlikely to meet its stated objectives. Some trials also include oversight by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board, which provides authorization for whether or not a trial may move forward at designated check points based on access to certain data from the trial and may halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. There are also requirements governing the reporting of ongoing preclinical studies and clinical trials and clinical trial results to public registries.

A sponsor who wishes to conduct a clinical trial outside of the United States may, but need not, obtain FDA authorization to conduct the clinical trial under an IND. If a foreign clinical trial is not conducted under an IND, the sponsor may submit data from the clinical trial to the FDA in support of a BLA. The FDA will accept a well-designed and well-conducted foreign clinical trial not conducted under an IND if the trial was conducted in accordance with GCP requirements, the clinical data are relevant to the US patient population in terms of medical practice, standard of care, and patient population definition, and the FDA is able to validate the data through an onsite inspection if deemed necessary.

For purposes of BLA approval, human clinical trials are typically conducted in three sequential phases that may overlap.

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Phase 1. For biologics being studied in oncology indications, the investigational product is initially introduced into patients with a broader range of malignancies, and may later focus on the target disease or condition. These trials are generally designed to test the safety, dosage tolerance, absorption, metabolism and distribution of the investigational product in humans, to identify possible side effects associated with increasing doses, and, if possible, to gain early evidence on effectiveness.

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Phase 2. The investigational product is administered to a limited patient population with a specified disease or condition to evaluate the preliminary efficacy, optimal dosages and dosing schedule and to identify possible adverse side effects and safety risks and additional information on PK and PD. Multiple Phase 2 clinical trials may be conducted to obtain information prior to beginning larger and more expensive Phase 3 clinical trials.

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Phase 3. The investigational product is administered to an expanded patient population to further evaluate dosage, to provide statistically significant evidence of clinical efficacy and to further test for safety, purity and potency for an intended use, and generally at multiple geographically dispersed clinical trial sites. These clinical trials are intended to establish the overall risk/benefit ratio of the investigational product and to provide an adequate basis for product approval. These trials usually include comparisons with placebo and/or other comparator treatments.

In some cases, the FDA may require, or companies may voluntarily pursue, additional clinical trials after a product is approved to gain more information about the product. These so-called Phase 4 trials may be made a condition to approval of the BLA. Concurrent with clinical trials, companies may complete additional animal studies and develop additional information about the biological characteristics of the product candidate and must finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, must develop methods for testing the identity, strength, quality and purity of the final product, or for biologics, the safety, purity and potency. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

BLA Submission and Review

Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, the results of product development, nonclinical studies and clinical trials are submitted to the FDA as part of a BLA requesting approval to market the product for one or more indications. The BLA must include all relevant data available from pertinent preclinical studies and clinical trials, including negative or ambiguous results as well as positive findings, together with detailed information relating to the product’s chemistry, manufacturing, controls and proposed labeling, among other things. The submission of a BLA requires payment of a substantial application user fee to the FDA, unless a waiver or exemption applies.

Once a BLA has been submitted, the FDA’s goal is to review standard applications within ten months after it accepts the application for filing, or, if the application qualifies for priority review, six months after the FDA accepts the application for filing. In both standard and priority reviews, the review process often includes multiple FDA requests for additional information or clarification. The FDA reviews a BLA to determine, among other things, whether a product is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency. The FDA may convene an advisory committee to provide clinical insight on application review questions. Before approving a BLA, the FDA will typically inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications.

Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCPs. If the FDA determines that the application, manufacturing process or manufacturing facilities are not acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

After the FDA evaluates a BLA and conducts inspections of manufacturing facilities where the investigational product and/or its biopharmaceutical substance will be produced, the FDA may issue an approval letter or a Complete Response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A Complete Response letter will describe all of the deficiencies that the FDA has identified in the BLA, except that where the FDA determines that the data supporting the application are inadequate to support approval, the FDA may issue the Complete Response letter without first conducting required inspections, testing submitted product lots and/or reviewing proposed labeling. In issuing the Complete Response letter, the FDA may recommend actions that the applicant might take to place the BLA in condition for approval, including requests for additional information or clarification. The FDA may delay or refuse approval of a BLA if applicable regulatory criteria are not satisfied, require additional testing or information and/or require post-marketing testing and surveillance to monitor safety or efficacy of a product. Further, FDA’s “real-time” release of newly issued Complete Response Letters associated with withdrawn or abandoned applications, if applicable to any of our product candidates, can materially impact our business and competitive advantage.

If regulatory approval of a product is granted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may approve the BLA with a Risk Evaluation and Management Strategy (REMS) to ensure the benefits of the product outweigh its risks. A REMS is a safety strategy to manage a known or potential serious risk associated with a product and to enable patients to have continued access to such medicines by managing their safe use, and could include medication guides, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. Once approved, the FDA may withdraw the product approval if compliance with pre- and post-marketing requirements is not maintained or if problems occur after the product reaches the marketplace. The FDA may require one or more Phase 4 post-market trials and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization and may limit further marketing of the product based on the results of these post-marketing studies.

Expedited Development and Review Programs

The FDA offers a number of expedited development and review programs for qualifying product candidates. The Fast Track program is intended to expedite or facilitate the process for reviewing new products that meet certain criteria. Specifically, new products are eligible for Fast Track designation if they are intended to treat patients with a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a Fast Track product has opportunities for frequent interactions with the review team during product development and, once a BLA is submitted, the product may be eligible for priority review. A Fast Track product may also be eligible for rolling review, where the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

A product intended to treat patients with a serious or life-threatening disease or condition may also be eligible for breakthrough therapy designation to expedite its development and review. A product can receive breakthrough therapy designation if preliminary clinical evidence indicates that the product, alone or in combination with one or more other drugs or biologics, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product, including involvement of senior managers.

Any marketing application for a biologic submitted to the FDA for approval, including a product with a Fast Track designation and/or breakthrough therapy designation, may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as priority review and accelerated approval. A product is eligible for priority review if it has the potential to provide a significant improvement in the treatment, diagnosis or prevention of a serious disease or condition. For original BLAs, priority review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date (as compared to ten months under standard review).

Additionally, products studied for their safety and effectiveness in treating patients with serious or life-threatening diseases or conditions may receive accelerated approval upon a determination that the product has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. As a condition of accelerated approval, the FDA will generally require the sponsor to perform adequate and well-controlled post-marketing clinical trials to verify and describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval preapproval of promotional materials, which could adversely impact the timing of the commercial launch of the product. The Food and Drug Omnibus Reform Act made several changes to the FDA’s authorities and its regulatory framework, including, among other changes, reforms to the accelerated approval pathway, such as requiring the FDA to specify conditions for post-approval study requirements and setting forth procedures for the FDA to withdraw a product on an expedited basis for non-compliance with post-approval requirements.

Fast track designation, breakthrough therapy designation and priority review do not change the standards for approval but may expedite the development or approval process. Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biologic intended to treat patients with a rare disease or condition, which is a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States for which there is no reasonable expectation that the cost of developing and making available in the United States a drug or biologic for this type of disease or condition will be recovered from sales in the United States for that drug or biologic. Orphan drug designation must be requested before submitting a BLA. After the FDA grants orphan drug designation, the generic identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. The orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review or approval process.

If a product that has orphan drug designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan drug exclusive approval (or exclusivity), which means that the FDA may not approve any other applications, including a full BLA, to market the same biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug or biologic for the same disease or condition, or the same drug or biologic for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the BLA application fee.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

In a 2021 court case, the court expanded the scope of orphan drug exclusivity by finding that orphan drug exclusivity applies to all uses or indications within an entire disease or condition. This position was in contrast to the FDA’s longstanding view which ties the scope of orphan drug exclusivity to the uses or indications for which a drug is approved, and thus permits other sponsors to obtain approval of a drug for new uses or indications within the same orphan designated disease or condition that have not yet been approved. The Consolidated Appropriations Act of 2026, signed into law in February 2026, codified this longstanding FDA interpretation of the Orphan Drug Act, allowing the FDA to approve multiple versions of the same orphan drug for different subindications and subpopulations.

In June 2024, the U.S. Supreme Court overruled the Chevron doctrine, which gives deference to regulatory agencies’ statutory interpretations in litigation against federal government agencies, such as the FDA, where the law is ambiguous. This landmark Supreme Court decision may invite various stakeholders to bring lawsuits against the FDA to challenge longstanding decisions and policies, such as market exclusivities, which could lead to uncertainties in the industry. Further, changes in the leadership of the FDA and other federal agencies under the current U.S. presidential administration may lead to new policies, changes in the regulations, or disruptions to the normal operations of federal agencies, any of which may impact our clinical development plans.

Post-Approval Requirements

Any products manufactured or distributed by us pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to facility registration, biopharmaceutical product listing, record-keeping, reporting of adverse experiences, periodic reporting, product sampling and distribution and advertising and promotion of the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing user fee requirements, under which the FDA assesses an annual program fee for each product identified in an approved BLA. Biologic manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMPs, which impose certain procedural and documentation requirements upon us and our third-party manufacturers. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMPs and impose reporting requirements upon us and any third-party manufacturers that we may decide to use. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMPs and other aspects of regulatory compliance. Further, if there are any modifications to the drug or biologic, including changes in indications, labeling or manufacturing processes or facilities, the applicant may be required to submit and obtain FDA approval of a new BLA or a supplement submission, which may require the development of additional preclinical studies, clinical trials, data and/or assays, such as comparability protocols.

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

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Restrictions on the marketing or manufacturing of a product, complete withdrawal of the product from the market or product recalls.

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Fines, warning letters or holds on post-approval clinical trials.

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Refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of existing product approvals.

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Product seizure or detention, or refusal of the FDA to permit the import or export of products.

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Consent decrees, corporate integrity agreements, debarment or exclusion from federal healthcare programs.

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Mandated modification of promotional materials and labeling and the issuance of corrective information.

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The issuance of safety alerts, Dear Healthcare Provider letters, press releases and other communications containing warnings or other safety information about the product.

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Injunctions or the imposition of civil or criminal penalties.

The FDA closely regulates the marketing, labeling, advertising and promotion of biologics. A company can make only those claims relating to safety and efficacy, purity and potency that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses.

Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested by us and approved by the FDA. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products.

Biosimilars and Reference Product Exclusivity

The Patient Protection and Affordable Care Act, or ACA, includes a subtitle called the Biologics Price Competition and Innovation Act of 2009, or BPCIA, which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA approved reference biological product.

Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity and potency, can be shown through analytical studies, animal studies and a clinical trial or trials. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law. Additionally, prescribing physicians are free to specify “Do Not Substitute” in prescriptions, which would prohibit pharmacists from substituting a branded biologic product for a biosimilar product.

The BPCIA is complex and continues to be interpreted and implemented by the FDA. In addition, government proposals have sought to reduce the 12-year reference product exclusivity period. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. As a result, the ultimate impact, implementation and impact of the BPCIA are subject to uncertainty.

Government Regulation Outside of the United States

In addition to regulations in the United States, we are subject to a variety of regulations in other jurisdictions where we seek to commercialize any of our product candidates, including countries in Europe and Asia. Such foreign regulations govern, among other things, research and development, clinical trials, testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, advertising and other promotional practices involving biological products as well as authorization and approval of our product candidates. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries.

Whether or not we obtain FDA approval for a product candidate, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of a clinical trial or marketing of a product in those countries. Certain countries outside of the United States have a similar approval process that requires the submission of a clinical trial application, or CTA, much like the IND prior to the commencement of human clinical trials. In the European Union, for example, a CTA must be submitted for each clinical trial to each country’s national health authority and an independent ethics committee, much like the FDA and an IRB, respectively. Once the CTA is approved in accordance with a country’s requirements, the corresponding clinical trial may proceed. 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 must be conducted in accordance with GCP requirements, applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

European Union Drug Development

Similar to the United States, the various phases of preclinical and clinical research in the European Union are subject to significant regulatory controls. Although the E.U. Clinical Trials Directive 2001/20/EC has sought to harmonize the E.U. clinical trials regulatory framework, setting out common rules for the control and authorization of clinical trials in the European Union, the E.U. Member States have transposed and applied the provisions of the Directive differently. This has led to significant variations in the member state regimes. Under the current regime, before a clinical trial can be initiated, it must be approved in each of the E.U. countries where the trial is to be conducted by two distinct bodies: the National Competent Authority (NCA) and one or more Ethics Committees (ECs). Under the current regime, all suspected unexpected serious adverse reactions to the investigated drug that occur during the clinical trial have to be reported to the NCA and ECs of the Member State where they occurred. The Clinical Trials Regulation EU No 536/2014, which entered into force in January 2022 with a transition period and aims at harmonizing and streamlining clinical-trial authorization, simplifying adverse-event reporting procedures, improving the supervision of clinical trials and increasing their transparency. From January 31, 2025, or the end of the transition period, any trials approved under the Clinical Trials Directive that continue running will need to comply with the Clinical Trials Regulation, and their sponsors must enter information on the trials in the Clinical Trials Information System.

In the European Economic Area (EEA), which is comprised of the 27 Member States of the European Union (excluding Croatia), Norway, Iceland and Liechtenstein, medicinal products can only be commercialized after obtaining a Marketing Authorization (MA). There are two types of Marketing Authorizations:

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The Community MA is issued by the European Commission through the Centralized Procedure, based on the opinion of the Committee for Medicinal Products for Human Use (CHMP), of the European Medicines Agency (EMA), and is valid throughout the entire territory of the EEA. The Centralized Procedure is mandatory for certain types of products, such as biotechnology medicinal products, orphan medicinal products, advanced-therapy medicines such as gene-therapy, somatic cell-therapy or tissue-engineered medicines and medicinal products containing a new active substance indicated for the treatment of HIV, AIDS, cancer, neurodegenerative disorders, diabetes, auto-immune and other immune dysfunctions and viral diseases. The Centralized Procedure is optional for products containing a new active substance not yet authorized in the EEA, or for products that constitute a significant therapeutic, scientific or technical innovation or for products that are in the interest of public health in the European Union.

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National MAs, which are issued by the competent authorities of the Member States of the EEA and only cover their respective territory, are available for products not falling within the mandatory scope of the Centralized Procedure. Where a product has already been authorized for marketing in a Member State of the EEA, this National MA can be recognized in another Member States through the Mutual Recognition Procedure. If the product has not received a National MA in any Member State at the time of application, it can be approved simultaneously in various Member States through the Decentralized Procedure. Under the Decentralized Procedure an identical dossier is submitted to the competent authorities of each of the Member States in which the MA is sought, one of which is selected by the applicant as the Reference Member State (RMS). The competent authority of the RMS prepares a draft assessment report, a draft summary of the product characteristics (SPC) and a draft of the labeling and package leaflet, which are sent to the other Member States (referred to as the Member States Concerned) for their approval. If the Member States Concerned raise no objections, based on a potential serious risk to public health, to the assessment, SPC, labeling or packaging proposed by the RMS, the product is subsequently granted a national MA in all the Member States (i.e., in the RMS and the Member States Concerned).

Under the above described procedures, before granting the MA, the EMA or the competent authorities of the member states of the EEA make an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

Other U.S Healthcare Laws and Compliance Requirements

Biopharmaceutical companies are subject to additional healthcare regulation and enforcement by the federal government and by authorities in the states and foreign jurisdictions in which they conduct their business. Research, manufacturing, sales, promotion and other activities following product approval are subject to regulation by numerous regulatory authorities in the United States in addition to the FDA, including the U.S. Centers for Medicare & Medicaid Services, or CMS, other divisions of the Department of Health and Human Services, the Department of Justice, the Drug Enforcement Administration, the Consumer Product Safety Commission, the Federal Trade Commission, the Occupational Safety & Health Administration, the Environmental Protection Agency, and state and local governments. For example, in the United States, sales, marketing and scientific and educational programs also must comply with state and federal fraud and abuse laws, false claims laws, transparency laws, government price reporting and health information privacy and security laws. These laws include the following:

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The federal Anti-Kickback Statute, which makes it illegal for any person, including a prescription drug manufacturer (or a party acting on its behalf), to knowingly and willfully solicit, receive, offer or pay any remuneration that is intended to induce or reward referrals, including the purchase, recommendation, order or prescription of a particular drug, for which payment may be made under a federal healthcare program, such as Medicare or Medicaid. Moreover, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively, the ACA, provides that the government may assert 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 civil False Claims Act, or FCA. In addition, the intent standard under the federal Anti-Kickback Statute was amended by the ACA to eliminate the need to prove specific intent and actual knowledge to establish an Anti-Kickback Statute violation.

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The federal civil and criminal false claims, including the FCA that can be enforced by private citizens through civil whistleblower or qui tam actions, prohibit individuals or entities from, among other things, knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government.

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The civil monetary penalties laws impose 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 healthcare 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, or offering or transferring remuneration to a federal healthcare beneficiary that a person knows or should know is likely to influence the beneficiary’s decision to order or receive items or services reimbursable by the government from a particular provider or supplier.

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The Federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, prohibits, among other things, executing or attempting to execute a scheme to defraud any healthcare benefit program or making false statements relating to healthcare matters. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and their implementing regulations, also imposes obligations, including mandatory contractual terms, on certain covered healthcare providers, health plans, and healthcare clearinghouses and their respective business associates that perform services for them that involve the use, or disclosure of, individually identifiable health information as well as their covered subcontractors, with respect to safeguarding the privacy, security and transmission of individually identifiable health information.

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Federal consumer protection and unfair competition laws, which broadly regulate marketplace activities and activities that potentially harm consumers.

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The FDCA, which prohibits, among other things, the adulteration or misbranding of drugs, biologics and medical devices.

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The federal Physician Payments Sunshine Act requires applicable manufacturers of covered drugs, medical devices, biologics and medical supplies for which payment is available under Medicare, Medicaid, or the Children’s Health Insurance Program, with specific exceptions, to annually report to CMS information regarding payments and other transfers of value made in the previous year to covered recipients, including physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), certain non-physician healthcare professionals (such as physician assistants and nurse practitioners, among others) and teaching hospitals, as well as information regarding ownership and investment interests held by physicians and their immediate family members.

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The distribution of pharmaceutical products is subject to additional requirements and regulations, including extensive record-keeping, licensing, price reporting, storage and security requirements intended to prevent the unauthorized sale of pharmaceutical products. Pricing and rebate programs must also comply with the Medicaid rebate requirements of the U.S. Omnibus Budget Reconciliation Act of 1990 and more recent requirements in the ACA. If products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. For example, products must meet applicable child-resistant packaging requirements under the U.S. Poison Prevention Packaging Act. Manufacturing, sales, promotion and other activities also are potentially subject to federal and state consumer protection and unfair competition laws.

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The Foreign Corrupt Practices Act, or 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, if any, and to devise and maintain an adequate system of internal accounting controls for international operations.

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Analogous state and foreign laws and regulations, such as state anti-kickback, anti-referral and false claims laws, which may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers, state laws that require biotechnology or pharmaceutical companies to comply with the biotechnology or pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government and may require drug manufacturers to report certain information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures, state laws that require biotechnology companies to report information on the pricing of certain drug products, state and local laws that require the registration of pharmaceutical sales representatives, and state and foreign laws that govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts; and state laws related to insurance fraud in the case of claims involving private insurers.

Because of the breadth of these laws and the narrowness of available statutory and regulatory exemptions or safe harbors, it is possible that some of our activities, such as stock-option compensation paid to physicians, could be subject to challenge under one or more of such laws. The growth of our business and sales organization and our expansion outside of the United States may increase the potential of violating these laws or our internal policies and procedures. Any action brought against us for violations of these laws or regulations, even successfully defended, could cause us to incur significant legal expenses and divert our management’s attention from the operation of our business. Also, we may be subject to private “qui tam” actions brought by individual whistleblowers on behalf of the federal or state governments. If our operations are found to be in violation of any of the federal, state and foreign laws described above or any other current or future fraud and abuse or other healthcare laws and regulations that apply to us, we may be subject to penalties, including significant civil, criminal and administrative penalties, including damages, fines, disgorgement, imprisonment, exclusion from participation in government funded healthcare programs, such as Medicare and Medicaid, integrity oversight and reporting obligations, contractual damages, reputational harm, diminished profits and future earnings, injunctions, requests for recall, seizure of products, total or partial suspension of production, denial or withdrawal of product approvals or refusal to allow a firm to enter into supply contracts, including government contracts, and we could be required to curtail or cease our operations. Any of the foregoing consequences could seriously harm our business and our financial results.

Coverage and Reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we may 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 availability of coverage and adequate reimbursement from third-party payors. Third-party payors include government programs such as Medicare or Medicaid, managed care plans, private health insurers and other organizations. These third-party payors may deny coverage or reimbursement for a product or therapy in whole or in part if they determine that the product or therapy was not medically appropriate or necessary. Third-party payors may attempt to control costs by limiting coverage to specific drug products on an approved list, or formulary, which might not include all of the FDA-approved drug products for a particular indication, and by limiting the amount of reimbursement for particular procedures or drug treatments. Additionally, coverage and reimbursement for drug products can differ significantly from payor to payor. The Medicare and Medicaid programs are often used as models by private payors and other governmental payors to develop their coverage and reimbursement policies for drugs and biologics. However, one third-party payor’s decision to cover a particular drug product does not ensure that other payors will also provide coverage for the product or will provide coverage at an adequate reimbursement rate.

The cost of pharmaceuticals continues to generate substantial governmental and third-party payor interest. We expect that the pharmaceutical industry will experience pricing pressures due to the trend toward managed healthcare, the increasing influence of managed care organizations and additional legislative proposals. Third-party payors are increasingly challenging the price and examining the medical necessity and cost effectiveness of medical products and services, in addition to their safety and efficacy. We may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of our products to obtain third-party payor coverage, 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 drug product does not imply that an adequate reimbursement rate will be approved. 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.

Some third-party payors also require pre-approval of coverage for new or innovative drug therapies before they will reimburse healthcare providers who use such therapies. While we cannot predict whether any proposed cost-containment measures will be adopted or otherwise implemented in the future, these requirements or any announcement or adoption of such proposals could have a material adverse effect on our ability to obtain adequate prices for our product candidates and to operate profitably. In international markets, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies. There can be no assurance that our products will be considered medically reasonable and necessary for a specific indication, that our products will be considered cost-effective by third-party payors, that coverage or an adequate level of reimbursement will be available or that third-party payors’ reimbursement policies will not adversely affect our ability to sell our products profitably.

Other Healthcare Laws

U.S. Healthcare Reform

The United States and some foreign jurisdictions are considering or have enacted a number of reform proposals to change the healthcare system. There is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality or expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by federal and state legislative initiatives, including those designed to limit the pricing, coverage and reimbursement of pharmaceutical and biopharmaceutical products, especially under government-funded health care programs, and increased governmental control of drug pricing.

The ACA, which was enacted in March 2010, substantially changed the way healthcare is financed by both governmental and private insurers in the United States, and significantly affected the pharmaceutical industry. The ACA contains a number of provisions of particular import to the pharmaceutical and biotechnology industries, including, but not limited to, those governing enrollment in federal healthcare programs, a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected, a new licensure framework for follow on biologic products, and annual fees based on pharmaceutical companies’ share of sales to federal health care programs. In January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, reduced Medicare payments to several providers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

The Bipartisan Budget Act of 2018, or BBA, among other things, amended the ACA, effective January 1, 2019, to close the coverage gap in most Medicare Part D drug plans. In December 2018, CMS published a new final rule permitting further collections and payments to and from certain ACA-qualified health plans and health insurance issuers under the ACA risk adjustment program in response to the outcome of federal district court litigation regarding the method CMS uses to determine this risk adjustment. However, on April 27, 2020, the U.S. Supreme Court reversed a Federal Circuit decision that previously upheld Congress’ denial of $12 billion in “risk corridor” funding. There have been legislative and judicial efforts to repeal, replace, or change some or all of the ACA, including measures taken during the Trump administration. In June 2021 the U.S. Supreme Court held that Texas and other challengers had no legal standing to challenge the ACA, dismissing the case on procedural grounds without specifically ruling on the constitutionality of the ACA. Thus, the ACA will remain in effect in its current form. It is possible that the ACA will be subject to judicial or Congressional challenges in the future. It is unclear how any such challenges and healthcare measures promulgated by the Trump administration will impact the ACA, our business, financial condition and results of operations.

Other legislative changes have been proposed and adopted since the ACA was enacted. These changes include aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, effective April 1, 2013, which will stay in effect through 2032, unless additional congressional action is taken. Moreover, there has recently been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several congressional inquiries and proposed and enacted legislation designed, among other things, to bring more transparency to product pricing, to review the relationship between pricing and manufacturer patient programs, and to reform government program reimbursement methodologies for pharmaceutical products. For example, under the American Rescue Plan Act of 2021, Medicaid statutory rebates are no longer capped at 100% of the average manufacturer price. Elimination of this cap may require pharmaceutical manufacturers to pay more in rebates than it receives on the sale of products, which could have a material impact on our business. In August 2022, Congress passed the Inflation Reduction Act of 2022, which includes prescription drug provisions that have significant implications for the pharmaceutical industry and Medicare beneficiaries, including allowing the federal government to negotiate a maximum fair price for certain high-priced single source Medicare drugs, imposing penalties and excise tax for manufacturers that fail to comply with the drug price negotiation requirements, requiring inflation rebates for all Medicare Part B and Part D drugs, with limited exceptions, if their drug prices increase faster than inflation, and redesigning Medicare Part D to reduce out-of-pocket prescription drug costs for beneficiaries, among other changes. Only high-expenditure single-source drugs that have been approved for at least seven years (11 years for single-source biologics) can qualify 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 drugs in 2023, negotiations began in 2024, and the negotiated maximum fair price for each drug has been announced. CMS has selected 15 additional

Medicare Part D drugs for negotiated maximum fair pricing in 2027. For 2028, up to 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, up to 20 additional Part B or Part D drugs will be selected. The impact of these legislative, executive, and administrative actions and any future healthcare measures and agency rules implemented by the current U.S. presidential administration on us and the pharmaceutical industry as a whole is unclear. Various industry stakeholders have initiated lawsuits against the federal government asserting that the price negotiation provisions of the Inflation Reduction Act are unconstitutional. The impact of these judicial challenges and future regulations, healthcare measures and agency rules by the government on us and the pharmaceutical industry as a whole is currently unknown. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability, or commercialize our product candidates if approved. Complying with any new legislation and regulatory changes could be time-intensive and expensive, resulting in a material adverse effect on our business. At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. For example, a number of states are considering or have recently enacted state drug price transparency and reporting laws that could substantially increase our compliance burdens and expose us to greater liability under such state laws once we begin commercialization after obtaining regulatory approval for any of our products. FDA has authorized the state of Florida to develop a drug importation program to import certain prescription drugs from Canada for a limited period to help reduce drug costs, provided that Florida’s Agency for Health Care Administration meets the requirements set forth by the FDA. Other states may follow Florida. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could affect the prices we may obtain for any of our product candidates for which we may obtain regulatory approval or the frequency with which any such product candidate, if approved, is prescribed or used.

Employees and Human Capital Resources

As of December 31, 2025,we had 43 employees, 11 of whom hold Ph.D. or M.D. degrees and 29 of whom were engaged in research and development activities. None of our employees are represented by a labor union and we believe we maintain good relations with our employees. We rely on skilled, innovative, and passionate employees to conduct our research, development and business activities. Our employees are united by our goal of developing therapies that help patients fight cancer. Developing a diverse, equitable and inclusive culture is essential to our success and we are committed to building a workplace where all individuals feel welcomed and valued.

The biopharmaceutical industry is highly competitive and recruiting and retaining employees is critical to the continued success of our business. Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and new employees, advisors and consultants. The principal purposes of our equity and cash incentive plans are to attract, retain and reward personnel through the granting of stock-based and cash-based compensation awards, in order to increase stockholder value and the success of our company by motivating such individuals to perform to the best of their abilities and achieve our objectives. We also offer a collaborative work environment, flexible or remote work arrangements, ongoing professional development opportunities, career advancement opportunities, and a culture that values diversity and inclusion.

Corporate Information

Our predecessor company, ALX Oncology Limited, an Irish private company limited by shares, was initially incorporated in Ireland on March 13, 2015 under the name Alexo Therapeutics Limited and changed its name to ALX Oncology Limited on October 11, 2018. We were then incorporated in Delaware on April 1, 2020 under the name ALX Oncology Holdings Inc. We present the information included in this Annual Report on Form 10-K as that of ALX Oncology Holdings Inc. unless such information refers to a date prior to April 1, 2020, in which case it reflects that of our predecessor company.

Our principal executive offices are located at 323 Allerton Avenue, South San Francisco, California, 94080. Our telephone number is 650-466-7125. Our website address is alxoncology.com.

ALXO US Equity

ALXO · 10-K · period ended 2025-12-31

Item 1. Business.

ALXO US Equity☆

ALXO · 10-K · period ended 2025-12-31

Item 1. Business.

ALXO US Equity