MORRISTOWN, N.J., May 30, 2026
Whitehawk Therapeutics announced new real-world data at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting highlighting SEZ6 as a highly expressed and clinically relevant therapeutic target across small cell lung cancer (SCLC) and other neuroendocrine tumors. The findings reinforce the development strategy for the company’s investigational antibody-drug conjugate (ADC), HWK-206, which targets SEZ6 and is expected to enter clinical testing later this year. The analysis demonstrated that SEZ6 is consistently expressed at high levels across multiple neuroendocrine malignancies, positioning it as a potentially valuable target for next-generation cancer therapies.
SEZ6 Outperforms Existing and Emerging ADC Targets in SCLC
The study revealed that SEZ6 expression exceeded several approved and emerging ADC targets in SCLC, including HER2, B7-H3, DLL3, PD-L1, and PD-1. Researchers reported that SEZ6 levels were at least three times higher than these targets in SCLC samples. In prostate neuroendocrine carcinoma, SEZ6 expression was found to be two- to six-fold higher than B7-H3, DLL3, and TROP2.
Importantly, the highest SEZ6 expression was observed in SCLC-A and SCLC-N molecular subtypes, which account for approximately 90% of SCLC cases and are characterized by strong neuroendocrine signaling. The target also maintained high expression across different disease stages and metastatic settings, suggesting broad applicability across patient populations.
Correlation with DLL3 Supports Future Combination Strategies
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Another significant finding from the analysis was the positive correlation between SEZ6 and DLL3 expression across neuroendocrine carcinomas. DLL3 has already emerged as an important therapeutic target in SCLC, and the observed relationship suggests potential opportunities for combination treatment approaches.
Investigators noted that SEZ6’s enrichment in neuroendocrine-high tumors and its overlap with DLL3 biology could provide a foundation for future combination regimens aimed at improving outcomes in patients with difficult-to-treat cancers. The data further strengthen the scientific rationale for targeting SEZ6 as part of a broader neuroendocrine tumor treatment strategy.
HWK-206 Advances Toward Clinical Development
Whitehawk Therapeutics stated that its lead SEZ6-directed ADC, HWK-206, utilizes a unique biparatopic design that binds two distinct epitopes on the target protein. This dual-binding approach is intended to enhance tumor targeting, improve internalization, and potentially deliver greater anti-tumor activity than conventional single-epitope ADCs. Preclinical studies have shown encouraging activity, with HWK-206 demonstrating the potential to outperform competing ADC candidates.
The company plans to submit an Investigational New Drug (IND) application in mid-2026, followed by the initiation of a Phase 1 clinical trial during the third quarter of 2026 in patients with SCLC and other neuroendocrine tumors. Company executives emphasized that the ASCO 2026 findings provide further validation of SEZ6 as a promising oncology target and support continued advancement of HWK-206 toward clinical development.
Source: Whitehawk Therapeutics press release
