Dana-Farber said researchers will present primary analysis data from the Phase 3 DeLLphi-305 trial of tarlatamab plus durvalumab versus durvalumab alone in extensive-stage small cell lung cancer at ESMO 2026. The study targets patients whose first-line regimen included durvalumab, platinum chemotherapy, and etoposide, evaluating whether adding tarlatamab improves maintenance outcomes. The company’s release confirms the presentation of the primary analysis but does not disclose numerical efficacy or safety results. As a result, the immediate impact for the market and peers is informational—what’s known is the trial design, timing, and the specific maintenance question—rather than any magnitude of benefit. For trial watchers, DeLLphi-305 is a key late-stage readout aligned with the broader push to refine maintenance strategies in a disease where subsequent lines are often rapid and prognosis-dependent. The ESMO slot also increases attention on secondary endpoints and subgroup durability once results are released with the abstract.