Data demonstrate preclinical proof-of-concept for HWK-007, HWK-016 and HWK-206, underpinned by Whitehawk's proprietary Carbon Bridge Cysteine Re-pairing platform

Tumor regressions observed across various cancer models at low single‑digit mg/kg doses, with favorable tolerability (HNSTD 60 mg/kg) and low systemic levels of free payload (≤0.01% AUC)

Phase 1 trials for HWK-007 and HWK-016 are ongoing; an IND submission for HWK-206 is on track for mid-2026

MORRISTOWN, N.J., April 19, 2026 /PRNewswire/ -- Whitehawk Therapeutics, Inc. (NASDAQ:WHWK), a clinical-stage oncology therapeutics company applying advanced technologies to established tumor biology to efficiently deliver improved antibody drug conjugate (ADC) cancer treatments, today announced the presentation of new preclinical data across its ADC portfolio at the American Association for Cancer Research (AACR) Annual Meeting 2026, taking place April 17-22, 2026, in San Diego, CA.

"Across our three ADC programs, we have a consistent preclinical profile characterized by potent tumor regressions, high plasma stability and favorable tolerability in non‑human primates, coupled with low systemic levels of free payload," said David Dornan, PhD, Chief Scientific Officer of Whitehawk Therapeutics. "These data support the potential for our next‑generation bioconjugation and proprietary Carbon Bridge Cysteine Re-pairing linker-payload to deliver a differentiated, potentially best-in-class therapeutic index among TOP1i-based ADCs, which is fundamental to realizing the promise of ADCs for patients."

Overview of Preclinical Presentations

"Preclinical assessment of HWK-007, a next-generation, PTK7-targeting ADC with novel bioconjugation and linker-payload technology" (Poster #4439)

HWK-007 targets PTK7, the third most highly expressed tumor marker among clinically validated and emerging ADC targets, present in ~70% of tumors. HWK‑007 is being evaluated in an ongoing Phase 1 clinical trial in patients with non-squamous, EGFR wild-type non-small cell lung cancer; platinum-resistant ovarian cancer; and endometrial cancer (NCT07444814). Key preclinical findings include:

High‑affinity binding and efficient internalization across a range of PTK7 expression levels
Demonstrates potent binding, internalization and tumor cell-killing in a range of solid cancer cell lines
Exhibits bystander activity and produces tumor regressions at doses as low as 1 mg/kg in small cell lung cancer and ovarian cancer models
Demonstrates favorable pharmacokinetics and is well tolerated in non‑human primates with an HNSTD of 60 mg/kg (the maximal dose tested)
Demonstrates high stability with free payload of 0.0067% AUC detected in circulation

"Preclinical assessment of HWK-016, a next-generation, MUC16-targeting ADC with novel bioconjugation and linker-payload technology" (Minisymposium Oral Presentation #1324)

HWK‑016 targets the non‑shed extracellular domain of MUC16 to avoid binding to circulating CA125 and associated antigen sink effects observed with earlier MUC16‑directed ADCs. HWK‑016 is being evaluated in an ongoing Phase 1 clinical trial in patients with advanced ovarian and endometrial cancers (NCT07470853). Key preclinical findings include:

Selectively binds membrane‑bound MUC16 to ensure delivery to the tumor instead of circulating CA125
Demonstrates potent binding, internalization and tumor cell-killing, and is minimally impacted by exogenous CA125
Exhibits bystander activity, and produces tumor regressions at doses as low as 1 mg/kg in ovarian cancer xenograft models that shed high levels of CA125
Demonstrates favorable pharmacokinetics and is well tolerated in non‑human primates with an HNSTD of 60 mg/kg (the maximal dose tested)
Demonstrates high stability with free payload of <0.01% AUC detected in circulation

"Preclinical assessment of HWK-206, a next-generation, biparatopic, SEZ6-targeting ADC with novel bioconjugation and linker-payload technology" (Poster #4440)

HWK‑206 targets SEZ6 with a biparatopic antibody designed to enhance binding, receptor clustering and internalization. Whitehawk plans to submit an Investigational New Drug (IND) application for HWK‑206 in mid-2026 and initiate a Phase 1 clinical trial in Q3 2026. Key preclinical findings include:

Increased binding and internalization compared with a parental monoclonal antibody alone, and compared with clinical-stage ADC, ABBV-706
Greater inhibition of cell viability compared with ABBV-706 in cell lines with varying SEZ6 expression
Produces tumor regressions at doses as low as 2 mg/kg in small cell lung cancer models
Demonstrates favorable pharmacokinetics and is well tolerated in non‑human primates with an HNSTD of 60 mg/kg (the maximal dose tested)
Demonstrates high stability with free payload of 0.01% AUC detected in circulation

More information can be found on the AACR 2026 meeting website. The posters and presentation will be accessible on the Presentations page of the Investors & News section of the Company's website at www.whitehawktx.com following presentation at the meeting.

About Whitehawk Therapeutics

Whitehawk Therapeutics is a clinical-stage oncology therapeutics company applying advanced technologies to established tumor biology to efficiently deliver improved cancer treatments. Whitehawk's advanced three-asset ADC portfolio is engineered to overcome the limitations of first-generation predecessors to deliver a meaningful impact for patients with difficult-to-treat cancers. These assets are in-licensed from WuXi Biologics under an exclusive development and global commercialization agreement. More information on the Company is available at www.whitehawktx.com and connect with us on LinkedIn.

Forward-Looking Statements 

This press release contains certain forward-looking statements regarding the business of Whitehawk Therapeutics that are not a description of historical facts within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are based on the Company's current beliefs and expectations and may include, but are not limited to: plans related to the Company's development of its portfolio of ADC assets, including the anticipated timing of the submission of an IND in mid-2026 for HWK-206 and initiation of the related Phase 1 trial in Q3 2026; statements relating to expectations regarding the beneficial characteristics, optimized ADC design features, safety, efficacy and therapeutic effects with respect to the ADC portfolio, including the Company's bioconjugation and linker payload platform; and the sufficiency of the Company's existing capital resources and the expected timeframe to fund its future operating expenses and capital expenditure requirements. Actual results could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, uncertainties associated with preclinical and clinical development of the ADC portfolio, including potential delays in the commencement, enrollment and completion of clinical trials and inability to replicate results from earlier studies; the risk that unforeseen adverse reactions or side effects may occur in the course of testing of the ADC portfolio; and risks related to the Company's estimates regarding future expenses, capital requirements and need for additional financing.

Additional risks and uncertainties that could cause actual outcomes and results to differ materially from those contemplated by the forward-looking statements are included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, including under the caption "Item 1A. Risk Factors," and in Whitehawk's subsequent Quarterly Reports on Form 10-Q, and elsewhere in Whitehawk's reports and other documents that Whitehawk has filed, or will file, with the SEC from time to time and available at www.sec.gov.

All forward-looking statements in this press release are current only as of the date hereof and, except as required by applicable law, Whitehawk undertakes no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise. All forward-looking statements are qualified in their entirety by this cautionary statement. This cautionary statement is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Contact:

IR@whitehawktx.com

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SOURCE Whitehawk Therapeutics, Inc.

Whitehawk Therapeutics Presents Comprehensive Preclinical Data Highlighting its Next-Generation ADC Portfolio at the AACR 2026