Multinational phase 1 trial of obrixtamig for DLL3-positive small cell lung cancer or neuroendocrine carcinoma

Obrixtamig (BI 764532) is a delta-like ligand 3/CD3 IgG-like T-cell engager. A multinational phase 1b trial evaluated obrixtamig in patients with previously treated DLL3-positive small cell lung cancer (SCLC), extrapulmonary neuroendocrine carcinomas (epNEC), or large cell neuroendocrine carcinoma of the lung (LCNEC-L). Dose-limiting toxicities were reported in seven patients, most occurred during the initial step-up dose administration, and the maximum tolerated dose was not reached. Cytokine release syndrome was the most common treatment-related adverse event. Across all doses, regimes, and tumor types, the overall response rate was 23%, with a median duration of response 8.5 months. The authors conclude that these results support further exploration of obrixtamig in DLL3-positive SCLC, epNEC, and LCNEC-L.