On April 10, 2026 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, reported three posters from a real-world analysis supporting the therapeutic potential of targeting mucin 16 (MUC16) with a next-generation ADC for the treatment of ovarian and endometrial cancers at the Society of Gynecologic Oncology (SGO) 2026 Annual Meeting on Women’s Cancer, being held April 10-13, 2026, in San Juan, Puerto Rico.

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MUC16 is a cell-surface glycoprotein that promotes tumor cell proliferation, metastasis and immune evasion. MUC16 is overexpressed in multiple tumor types with limited expression in normal tissue. A large-scale RNA analysis demonstrated that MUC16 is highly and stably expressed across ovarian cancers and in the most aggressive and most common subtypes of endometrial cancer, including in later-stage disease, supporting its potential as a clinically meaningful ADC target and reinforcing the rationale for clinical development of HWK-016.

"Across both ovarian and endometrial cancers, MUC16 shows a high level of stable expression that is uncommon among many therapeutic targets," said Kathleen N. Moore, MD, Deputy Director and Director of Phase 1 Oncology Trials, The Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center. "The consistency of MUC16 expression across disease stage and platinum sensitivity supports the relevance of a MUC16-targeted ADC in earlier-line settings, as well as for heavily pretreated patients and as part of combination strategies."

Key Findings Include:

MUC16 in Ovarian Cancer

MUC16 has high, tumor‑selective expression, with concordance between MUC16 mRNA expression and MUC16 protein abundance by IHC.
MUC16 is highly expressed across most histologic subtypes, including the most common subtype, high-grade serous ovarian carcinoma (HGSOC), which accounts for ~70% of cases.
In HGSOC, MUC16 expression is stable across disease stages, metastatic status and platinum sensitivity, underscoring relevance in early- and late-line treatment settings.
MUC16 has the highest median expression, ranging from 2- to >100-fold higher than other clinically validated and emerging ADC targets, including NaPi2b, HER2, FRα, TROP2, B7-H4, CDH6 and CLDN6.
MUC16 in Endometrial Cancer

MUC16 has high, tumor‑selective expression, with concordance with MUC16 protein abundance by IHC.
MUC16 is most highly expressed in serous adenocarcinoma (the most aggressive subtype accounting for ~40% of deaths), followed by endometrioid adenocarcinoma (the most common subtype, accounting for ~90% of cases).
In serous adenocarcinoma, MUC16 expression is stable across disease stages and metastatic status, and has the highest median expression, 1.4- to 3.7-fold higher than other clinically validated and emerging ADC targets, including NaPi2b, HER2, TROP2, FRα and B7H4.
Earlier MUC16‑directed ADCs targeted the cleaved extracellular portion of the protein (CA125), which is shed into circulation, limiting tumor delivery. HWK‑016, Whitehawk’s investigational, next‑generation MUC16‑targeted ADC, is designed to overcome this antigen sink effect by selectively targeting the membrane‑bound, non‑shed portion of MUC16. HWK‑016 leverages a stable, cleavable linker to deliver a novel topoisomerase I (TOP1) inhibitor payload. HWK-016 is currently being evaluated in a Phase 1 clinical trial in patients with advanced ovarian and endometrial cancers [NCT07470853]. Initial clinical data are expected in the first half of 2027.

"The real-world data reported at SGO reinforce MUC16 as a ‘super expressed’ and durable target for gynecological cancers, strengthening the biological rationale for HWK-016," said Margaret Dugan, MD, Chief Medical Officer of Whitehawk Therapeutics. "By combining selective targeting of the membrane‑bound, non‑shed portion of MUC16 with our differentiated carbon‑bridge cystine‑repairing linker‑payload technology, HWK‑016 exemplifies our broader strategy of applying advanced ADC engineering to well‑validated tumor biology to potentially generate meaningfully improved outcomes for patients."

Poster Presentation Details:

Title: MUC16 in ovarian cancer: high, stable expression across histologic subtypes, disease stages, and platinum sensitivity status supports antibody-drug conjugate development
Presenter: Ursula A. Matulonis, MD, Dana-Farber Cancer Institute
Date & Time: April 12, 2026, 11:00 AM – 12:00 PM and 4:00 – 4:45 PM

Title: MUC16 as a therapeutic target: advancing antibody-drug conjugates for ovarian cancer treatment
Presenter: David M. O’Malley, MD, The Ohio State University
Date & Time: April 12, 2026, 11:00 AM – 12:00 PM and 4:00 – 4:45 PM

Title: High and stable MUC16 expression in endometrial cancer highlights potential for targeted antibody-drug conjugate development
Presenter: Kathleen N. Moore, MD, University of Nebraska Medical Center
Poster Tour – Group 9: Targeted Tactics and Therapies
Date & Time: April 12, 2026, 11:30 AM – 12:00 PM

The analysis was 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.

(Press release, Whitehawk Therapeutics, APR 10, 2026, View Source [SID1234664302])