China’s NMPA accepted the NDA for opamtistomig (LBL-024), a PD-L1/4-1BB-directed bispecific antibody, as monotherapy for previously treated advanced extrapulmonary neuroendocrine carcinoma (EP-NEC). The agency granted priority review, and the application is supported by registrational trial enrollment of 96 patients across 34 sites. The submission also reinforces 4-1BB’s growing role as an immune-activation lever in oncology. Opamtistomig is designed to block PD-L1–mediated immune suppression while conditionally activating 4-1BB agonist signaling, which targets exhausted T cells—particularly relevant for tumors described as immunologically “cold.”