New phase 1b DeLLphi-308 data presented at the International Association for the Study of Lung Cancer 2026 World Conference on Lung Cancer in Seoul reported safety and early antitumor activity for subcutaneous tarlatamab in extensive-stage small cell lung cancer. The study is testing a more convenient delivery format for a therapy already used to treat SCLC. The report positions subcutaneous administration as a potential operational shift for immunotherapy delivery, especially for patients who need ongoing dosing after first-line therapy. While the dataset is early, it adds to a growing emphasis on practicality alongside efficacy in SCLC. For the field, the update also adds context for how dosing logistics may evolve as tarlatamab and other DLL3-directed approaches move into broader settings. Clinicians will be watching for durability signals and for how administration route affects immune activation and tolerability. (Story coverage source: conference coverage.)