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
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.”
