Phase 3 tarlatamab (Amgen) DLL3×CD3 bispecific T‑cell engager compares SC vs IV dosing

Amgen’s DeLLphi-315 is a Phase 3, open-label, randomized, multicenter study in relapsed extensive-stage small cell lung cancer (ES-SCLC) after platinum-based first-line chemotherapy. Participants are randomized to receive tarlatamab either subcutaneously (SC) or intravenously (IV). Tarlatamab is a DLL3×CD3 bispecific T-cell engager that binds DLL3 on SCLC cells and CD3 on T cells to direct an immune attack against the cancer. The primary goal is to determine whether subcutaneous dosing can achieve drug exposure comparable to IV dosing, with additional measures of efficacy, safety, and tolerability. Tarlatamab is already an FDA-approved treatment for ES-SCLC that has progressed on or after platinum-based chemotherapy, so this study is not testing whether the drug works. Instead, it asks whether a subcutaneous version can preserve its activity while making treatment easier and more convenient to deliver.