PTK7 is the third most highly expressed tumor marker among clinically validated and emerging ADC targets, present in ~70% of tumors

PTK7 expression is stable across histologic subtype, disease stage and metastatic status in high-potential indications, including lung, ovarian and endometrial cancers

Findings support potential of PTK7 as a pan-tumor target, reinforcing Whitehawk’s development of PTK7-directed ADC HWK-007

MORRISTOWN, N.J., Oct. 24, 2025 /PRNewswire/ — Whitehawk Therapeutics, Inc. (Nasdaq: WHWK), an oncology therapeutics company applying advanced technologies to established tumor biology to efficiently deliver improved antibody drug conjugate (ADC) cancer treatments, today presented data from a real-world analysis of Protein Tyrosine Kinase 7 (PTK7) at the 2025 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics. As part of a collaboration between Whitehawk and Tempus AI, the analysis evaluated real-world data from the Tempus AI database and the Clinical Proteomic Tumor Analysis Consortium to, for the first time, robustly characterize PTK7 expression.

PTK7 is an oncofetal transmembrane pseudokinase that drives early embryonic development, has restricted expression in adult tissues and frequent overexpression in a wide range of cancers. There are no approved PTK7-directed ADCs.

This large-scale RNA analysis of >157,000 tumor samples, nearly half from metastatic lesions, confirms PTK7 as one of the most broadly and highly expressed targets across solid tumors, reinforcing its potential as a clinically meaningful pan-tumor ADC target, and further support development of HWK-007, Whitehawk’s PTK7-directed ADC candidate.

Key findings include:

PTK7 is expressed in ~70% of solid tumors.
PTK7 is the third most highly expressed tumor marker among clinically validated and emerging ADC targets, after HER2 and HER3.
Highest median PTK7 mRNA expression¹ observed in endometrial (7.4), ovarian (7.2), head and neck (7.1), non-small cell lung cancer (NSCLC) (6.9) and breast (6.7) tumors.
Stable expression across disease stages and metastatic status, underscoring relevance in both early- and late-stage disease.
Expression levels comparable to or exceeding clinically validated and emerging ADC targets:
- Lung cancer: Comparable to HER2, HER3, Trop-2 and cMET.
- Ovarian cancer: Comparable to HER2 and FRα; markedly higher than CDH6, B7-H4 and CLDN6.
- Endometrial cancer: Comparable to Trop-2; markedly higher than FRα, B7-H4 and HER2.

“These results emphasize the translational potential of PTK7 as a broadly expressed and stable target across solid tumors,” said Grace Dy, MD, Chief, Thoracic Oncology, Professor of Oncology, Department of Medicine, Roswell Park Comprehensive Cancer Center. “By demonstrating consistent expression across histologies, disease stages and sample types, this analysis builds on the foundational rationale for developing next-generation ADCs that have the potential to reach a wide range of patients.”

Whitehawk is advancing HWK-007, a PTK7-targeting ADC that leverages an advanced ADC technology platform which consists of a highly stable yet cleavable linker that delivers a Topoisomerase I (TOPO1) inhibitor payload. The Company plans to submit an Investigational New Drug application to the U.S. Food and Drug Administration for HWK-007 by year-end, with initial clinical evaluation planned in NSCLC, ovarian and endometrial cancers.

“These findings reinforce PTK7’s promise as one of the most compelling and underexplored ADC targets in oncology,” said Dave Lennon, PhD, President and Chief Executive Officer, Whitehawk Therapeutics. “As the third most abundant tumor marker across all cancer patients – present in approximately 70% of solid tumors – the opportunity for HWK-007 has never been clearer. We believe we are well positioned to develop a differentiated ADC that could have a meaningful impact for the nearly 750,000² patients in the US with PTK7-expressing cancers.”

The analysis was conducted as part of a previously announced collaboration between Whitehawk and Tempus AI. The abstract is available as a freely available supplement in the AACR journal Molecular Cancer Therapeuticshere.

About Whitehawk Therapeutics
Whitehawk Therapeutics is an 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, statements relating to: the anticipated timing of the Company’s development of its portfolio of ADC assets, including the expected timing to submit an Investigational New Drug application forHWK-007 by year-end; expectations regarding the beneficial characteristics, safety, efficacy, therapeutic effects of HWK-007 and the size of the potential PTK7 targeted market; and the sufficiency of the Company’s existing capital resources and the expected timeframe to fund the Company’s 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; failure to demonstrate the efficacy of the ADC portfolio in preclinical and clinical studies; the risk that unforeseen adverse reactions or side effects may occur in the course of testing of the ADC assets; 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, 2024, 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.

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¹ Among groups with sample sizes ≥4000.
² 2019 SEER Data