MUC16 Expression Remained High and Stable Following Standard-of-Care Therapies, Supporting Its Potential Utility in Both Combination Approaches and Relapsed Settings

High MUC16 Expression Was Associated with Poor Real-World Overall Survival in High-Grade Serous Ovarian Carcinoma, the Most Common Subtype of Ovarian Cancer

Findings Reinforce the Scientific Rationale for HWK-016, Whitehawk’s Next-Generation MUC16-Directed ADC Currently in Phase 1 Development

MORRISTOWN, N.J., Oct. 1, 2026 /PRNewswire/ — Whitehawk Therapeutics, Inc. (Nasdaq: WHWK), a clinical-stage oncology therapeutics company applying advanced technologies to established tumor biology to efficiently develop improved antibody drug conjugate (ADC) cancer treatments, today announced the presentation of two real-world analyses supporting mucin 16 (MUC16) as a durable therapeutic target and potential prognostic biomarker in ovarian cancer. These data will be presented at the International Gynecologic Cancer Society (IGCS) Annual Global Meeting taking place October 1-3, 2026, in Montreal, Canada.

In tumor samples from patients with ovarian cancer, MUC16 expression remained high and largely stable following standard-of-care (SoC) treatments, including platinum and non-platinum chemotherapy, bevacizumab-containing regimens, PARP inhibitors and mirvetuximab soravtansine. Treatment-associated changes in MUC16 expression were consistently small, and MUC16 demonstrated less treatment-associated variation than several other ADC targets, including FRα, TROP2 and NaPi2b. These findings suggest MUC16 is a durable therapeutic target for ADCs across multiple lines of therapy, and support development strategies that include both combination approaches and treatment in relapsed disease.

“For an ADC target to have broad clinical utility in ovarian cancer, it’s important that it remains consistently expressed as patients move through multiple lines of therapy,” said Margaret Dugan, MD, Chief Medical Officer of Whitehawk Therapeutics. “These findings suggest MUC16 is durable throughout the treatment continuum and support the exploration of HWK-016 both in combination with established therapies and in patients whose disease has progressed following prior treatment.”

In a separate analysis of patients with high-grade serous ovarian carcinoma (HGSOC) – the most common histologic subtype accounting for approximately 70% of cases – high tumor MUC16 expression was prognostically associated with poor real-world overall survival (rwOS). This association remained statistically significant after adjustment for key clinical and molecular covariates and was also observed among patients who were treatment-naïve at first metastatic diagnosis.

“Ovarian cancer continues to be a difficult-to-treat disease with new therapeutic approaches urgently needed,” said Robert L. Coleman, MD, Texas Oncology. “The observation that high MUC16 expression was independently associated with poorer real-world overall survival indicates it is an important marker of more aggressive disease biology, and supports the continued investigation of MUC16-directed ADCs in this disease.”

Poster Details:

Title: Durable and Treatment-Agnostic MUC16 Expression in Ovarian Cancer Supports Targeted Antibody-Drug Conjugate Development
Poster: 950
Presenter: Kathleen N. Moore, MD, University of Nebraska Medical Center, Omaha, Nebraska
Date & Time: E-Poster

Key Findings:

• MUC16 expression remained largely stable following platinum and non-platinum chemotherapy, bevacizumab-containing regimens, PARP inhibitors and mirvetuximab soravtansine.
• Findings suggest that the target may be suitable for MUC16-directed therapy after prior SoC treatment and in combination with standard early-line platinum-based treatment.
• Stable MUC16 expression is also observed in paired tumor samples.
• MUC16 demonstrated less treatment-associated variation than several late-stage ADC targets, including FRα, TROP2 and NaPi2b.

Title: High MUC16 Expression Is Associated With Poor Real-World Overall Survival in Patients With High-Grade Serous Ovarian Carcinoma
Poster: 519
Presenter: Robert L. Coleman, MD, Texas Oncology, The Woodlands, Texas
Date & Time: October 1, 2026, 2:35-2:40 ET

Key Findings:

• MUC16 expression at metastatic diagnosis was prognostically associated with poor rwOS.
• Results were similar in the treatment-naïve subpopulation.
• Eastern Cooperative Oncology Group performance status, BRCA mutation status and age at diagnosis were also independent prognostic factors of rwOS.
• High circulating CA125 was also associated with poor prognosis in patients with heavily pretreated HGSOC.

HWK‑016 is a MUC16-directed, next-generation ADC targeting the non-shed extracellular domain that is being evaluated in an ongoing Phase 1 clinical trial in patients with advanced ovarian and endometrial cancers (NCT07470853). 

These analyses were conducted as part of a previously announced collaboration between Whitehawk and Tempus AI. The posters will be accessible on the Presentations page of the Investors & News section of the Company’s website at www.whitehawktx.com.

About Whitehawk Therapeutics
Whitehawk Therapeutics is a clinical-stage oncology therapeutics company applying advanced technologies to established tumor biology to efficiently develop improved antibody drug conjugate (ADC) cancer treatments. Whitehawk’s portfolio includes HWK-007, HWK-016 and HWK-206, ADCs 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.

Whitehawk’s underlying ADC platform leverages CPT113 as the core linker-payload technology, enhanced with its proprietary Carbon Bridge Cysteine Re-pairing (CBCR) bioconjugation process to support improved stability and therapeutic index. More information on the Company is available at www.whitehawktx.com and connect with us on LinkedIn. Any references to the Company’s website or other online resources are provided solely for convenience and are not incorporated by reference into this press release. Investors should rely only on the information contained in this press release and the Company’s filings with the Securities and Exchange Commission.

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, statements relating to the potential therapeutic value and market opportunity for HWK-016 and expectations regarding the beneficial characteristics, design features and the potential targeted markets with respect to HWK-016. 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 HWK-016.

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:
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