Whitehawk Therapeutics Validates SEZ6 as High-Expression Target for Small Cell Lung Cancer ADC Development
核心洞察
Whitehawk Therapeutics (搜索) presented real-world analysis at ASCO 2026 demonstrating that SEZ6 (搜索) expression in small cell lung cancer exceeds approved and emerging ADC targets by at least 3-fold compared to HER2 (搜索), B7-H3 (搜索), DLL3 (搜索), PD-L1 (搜索) and PD-1 (搜索).
The analysis revealed SEZ6 (搜索) expression is highest in SCLC-A and SCLC-N molecular subtypes, which account for approximately 90% of all SCLC cases and are characterized by high neuroendocrine transcription factor expression.
SEZ6 (搜索) expression positively correlates with DLL3 (搜索) across neuroendocrine carcinomas, indicating potential for combination therapy approaches with existing DLL3-targeted treatments.
Whitehawk Therapeutics (搜索) has presented compelling real-world evidence supporting SEZ6 (搜索) as a highly expressed therapeutic target for small cell lung cancer (SCLC) and other neuroendocrine tumors, with expression levels significantly exceeding those of approved and emerging antibody-drug conjugate (ADC) targets. The findings were presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.
Superior Target Expression Profile
The large-scale RNA analysis demonstrated that SEZ6 (搜索), a cell surface transmembrane protein involved in neuronal development, shows remarkably high expression across SCLC and other neuroendocrine malignancies. In SCLC specifically, SEZ6 expression was at least 3-fold higher than established targets including HER2 (搜索), B7-H3 (搜索), DLL3 (搜索), PD-L1 (搜索), and PD-1 (搜索). The expression advantage extends to other neuroendocrine carcinomas, with SEZ6 showing 2- to 6-fold higher expression than B7-H3, DLL3, and TROP2 (搜索) in prostate neuroendocrine carcinoma.
"SEZ6 (搜索) demonstrates a compelling expression profile across SCLC and other neuroendocrine malignancies. In SCLC, it has levels of expression that are consistently high across disease stages and metastatic settings," said Afshin Dowlati, MD, from University Hospitals Seidman Cancer Center (搜索) and Case Western Reserve University. "The magnitude of SEZ6 expression relative to other therapeutic targets, along with its enrichment in neuroendocrine-high SCLC subtypes, supports its potential as an ADC target."
Molecular Subtype Distribution and Clinical Relevance
The analysis revealed that SEZ6 (搜索) expression is highest in SCLC-A and SCLC-N molecular subtypes, which collectively represent approximately 90% of SCLC cases. These subtypes are characterized by high expression of neuroendocrine transcription factors, making SEZ6 particularly relevant for the majority of SCLC patients. Importantly, expression remains consistently high across different disease stages and metastatic status, supporting potential therapeutic relevance across various treatment settings.
Combination Therapy Potential
A notable finding from the analysis was the positive correlation between SEZ6 (搜索) and DLL3 (搜索) expression across neuroendocrine carcinomas. This correlation suggests potential opportunities for combination approaches with DLL3-targeted therapies, potentially expanding treatment options for patients with these challenging malignancies.
HWK-206 Development Program
Whitehawk's lead candidate, HWK-206 (搜索), utilizes a dual epitope binding or biparatopic approach designed to potentially improve binding and internalization compared to single epitope ADCs. In preclinical models, HWK-206 has demonstrated the potential to outperform other single epitope ADCs currently in development.
"This real-world characterization of SEZ6 (搜索) expression across small cell lung cancer and other neuroendocrine tumors reinforce our conviction in SEZ6 as a clinically meaningful target for ADC development," said Margaret Dugan, MD, Chief Medical Officer of Whitehawk Therapeutics (搜索). "These findings add to the body of evidence supporting our biparatopic SEZ6-directed ADC, HWK-206 (搜索), and its potential to have a meaningful impact on patients with SCLC and neuroendocrine tumors."
Clinical Timeline
The company expects to submit an Investigational New Drug application for HWK-206 (搜索) in SCLC and neuroendocrine tumors in mid-2026, with Phase 1 trials planned to commence in Q3 2026. The analysis was conducted as part of a collaboration between Whitehawk and Tempus AI, demonstrating the company's commitment to leveraging real-world data to support its development programs.
The research represents a significant step forward in identifying and validating novel therapeutic targets for SCLC, a particularly aggressive form of lung cancer with limited treatment options. The superior expression profile of SEZ6 (搜索) compared to existing targets, combined with its broad expression across neuroendocrine tumor types, positions it as a promising candidate for next-generation ADC development.