Tarlatamab in Advanced Delta-like 3 (DLL3)-Expressing Tumors Including Neuroendocrine Neoplasms

This is a phase II, multicenter, basket trial to evaluate the safety, tolerability, and efficacy of tarlatamab in DLL3-expressing tumors. The study will enroll patients with advanced tumors, other than small cell lung cancer or neuroendocrine prostate cancer, that are confirmed to exhibit DLL3 expression. Patients will be treated with tarlatamab until disease progression, death, unacceptable adverse effects, or withdrawal of consent. A Simon's two-stage optimum design will be used \[1\]. The primary objective of this phase II trial is the overall response rate (ORR, as defined by confirmed complete and partial response) per RECIST v1.1 criteria. Our null hypothesis is an ORR of 10% or lower, based on the requirements for prior therapies, and our alternative hypothesis is an ORR of 30% or greater. We will utilize a Simon two-stage design, in which 10 patients will be entered into the first stage. If 2 or more patients show a response, then an additional 19 patients will be enrolled. If 6 or more patients out of 29 show a response, then the trial will reject the null hypothesis.