The story

A combination of pumitamig and elfetabart drozuntecan showed a 70.4% overall objective response rate in 71 patients with small cell lung cancer, according to Phase 1b/2 trial data presented at the International Association for the Study of Lung Cancer 2026 World Conference on Lung Cancer in Seoul. Among the patients evaluated as of July 7, 2026, one achieved a complete response, 49 achieved partial responses, and 16 had stable disease. Response rates varied by treatment line: 92.3% in first-line SCLC, 77.3% in second-line disease, and 52.4% in third line or later. As of June 2, 2026, treatment-related adverse events occurred in 75.6% of 193 patients, including grade 3 or higher events in 23.3%, mostly gastrointestinal or hematologic.

A separate Phase 1b study evaluated subcutaneous administration of tarlatamab in extensive-stage small cell lung cancer. Among 40 patients who received a 15 mg target dose as of March 5, 2026, treatment-related adverse events occurred in 85%, with 10% experiencing grade 3 or higher events. The most common events included injection-site reactions (50%), dysgeusia (45%), cytokine release syndrome (38%), and decreased appetite (20%). No grade 5 treatment-related adverse events occurred, and cytokine release syndrome events were predominantly low-grade.

A randomized Phase 2 study examined different dosing intervals for tarlatamab in small cell lung cancer patients who had undergone platinum-based chemotherapy. As of May 7, 2026, 252 patients were randomized to receive 10 mg every two weeks, 20 mg every three weeks, or 30 mg every four weeks. Blinded independent central review confirmed objective response rates of 40% in the every-two-week group, 31% in the every-three-week group, and 27% in the every-four-week group. Investigator-assessed response rates were 36%, 37%, and 31%, respectively.