China’s NMPA accepted the NDA for opamtistomig (LBL-024), a PD-L1/4-1BB–directed bispecific antibody, for previously treated advanced extrapulmonary neuroendocrine carcinoma (EP-NEC). The Center for Drug Evaluation granted priority review on July 10, 2026, with the regulatory decision expected to follow the next stage of the filing process. The submission is supported by a registrational study led by Lin Shen, MD, of Peking University Cancer Hospital. Enrollment was completed for 96 patients across 34 sites in August 2025. Previously reported results cited in the filing show an objective response rate of 33.3% in EP-NEC. If approved, opamtistomig would mark the first marketed therapy directly targeting 4-1BB and the first approved agonistic antibody against the costimulatory receptor in the setting described. The company positions the mechanism as combining PD-L1 immune suppression blockade with conditional 4-1BB agonist signaling aimed at reactivating exhausted T cells. The NDA also builds on broader development activity for opamtistomig across solid tumor indications in China, including one pivotal registration trial and multiple proof-of-concept studies, with detailed data slated for presentation at an international meeting.