Results from the Phase 1 DAREON-7 trial, presented at the North American Neuroendocrine Tumor Society (NANETS) 2025 Symposium, showed that adding obrixtamig, a T-cell engager, to standard chemotherapy produced strong responses in patients with DLL3-positive neuroendocrine carcinomas. The study reported a 72% objective response rate, with 88% of patients achieving disease control. The median duration of response was 8.8 months, and median progression-free survival reached 7.6 months.
Side effects were common but generally consistent with platinum-based chemotherapy. No dose-limiting toxicities were reported during the safety evaluation period. The most frequent serious side effects were neutropenia (80%) and anemia (40%), mainly related to chemotherapy. Cytokine release syndrome occurred in 72% of patients but was mild to moderate, and neurologic toxicity was rare.
The study enrolled 25 patients with DLL3-positive extrapulmonary or large cell neuroendocrine carcinomas. Patients received obrixtamig plus carboplatin and etoposide for six cycles, followed by maintenance obrixtamig. Researchers said the results are promising for these aggressive cancers and support moving forward with larger trials to determine whether this combination could become a new standard treatment.