At the World Conference on Lung Cancer (WCLC) 2025, several investigational treatments for small cell lung cancer (SCLC) showed promising yet mixed clinical trial results. BioNTech and Bristol Myers presented Phase II data for pumitamig, a bispecific PD-1 and VEGF inhibitor, achieving 76% tumor shrinkage in extensive-stage SCLC patients, supporting ongoing Phase III trials. Conversely, Summit Therapeutics’ ivonescimab, targeting PD-1 and VEGF, improved progression-free survival but failed to extend overall survival in a global Phase III study. Daiichi Sankyo and Merck’s antibody-drug conjugate ifinatamab deruxtecan reported nearly a 50% objective response rate, earning FDA breakthrough therapy designation for extensive-stage SCLC. These developments highlight both advancements and challenges in the rapidly evolving therapeutic landscape for aggressive lung cancers.