WCLC 2025: Bispecific antibody dose shows promising potential for extensive-stage SCLC

MD Anderson Research News September 08, 2025

Pumitamig is a novel bispecific antibody targeting both the PD-L1 checkpoint and VEGF, a driver of angiogenesis, being studied in patients with extensive-stage small cell lung cancer (ES-SCLC). Pumitamig plus chemotherapy was shown to improve outcomes for Chinese patients with SCLC, leading John Heymach, M.D., Ph.D., and colleagues to examine its optimal dose in a global Phase II trial of patients with treatment-naïve ES-SCLC. In 43 patients enrolled in cohort 1 – receiving pumitamig plus etoposide and carboplatin chemotherapy for four cycles followed by pumitamig maintenance – 22 patients received a lower dose of 20 mg/kg and 21 received a higher dose of 30 mg/kg. Among 38 evaluable patients, the overall response rate (ORR) was 85% and 66.7% with the low and high doses, respectively, with 89.5% of patients overall achieving early tumor shrinkage. Six patients (14%) discontinued pumitamig due to adverse events. These are the first results highlighting the therapeutic potential of a bispecific antibody targeting both checkpoint inhibition and angiogenesis in a global ES-SCLC patient population, supporting further development of pumitamig, which is currently being evaluated in Phase III trials. Heymach presented the results at the World Confernce on Lung Cancer (WCLC) on Sept. 8.