A Phase III, Multi-center, Open-label, Randomised, Controlled Trial of Intravenous Obrixtamig in Combination With Carboplatin and Etoposide vs. Carboplatin and Etoposide as First-line Therapy in DLL3-positive Patients With Unresectable Locally Advanced or Metastatic Extrapulmonary Neuroendocrine Carcinomas | Arctuva