The NMPA accepted the NDA for the PD-L1/4-1BB–directed bispecific antibody opamtistomig in previously treated advanced extrapulmonary NEC.
The Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) has accepted the new drug application (NDA) for opamtistomig (LBL-024), a PD-L1/4-1BB–directed bispecific antibody, as monotherapy for the treatment of patients with previously treated advanced extrapulmonary neuroendocrine carcinoma (EP-NEC).¹
The CDE granted the application priority review on July 10, 2026.
If approved, opamtistomig would become the first agent directly targeting 4-1BB to reach the market, as well as the first approved agonistic antibody, making 4-1BB the fourth immuno-oncology target with an approved therapy, after PD-1/PD-L1, CTLA-4, and LAG-3. The NDA is supported by results from a registrational study led by Lin Shen, MD, of Peking University Cancer Hospital in Beijing, China, which completed enrollment of 96 patients with EP-NEC across 34 sites in August 2025; detailed data are expected to be presented at a future international medical meeting.
“As the first 4-1BB-targeting bispecific antibody globally to advance into registrational clinical development, opamtistomig represents a significant breakthrough in the [management] of EP-NEC, a highly aggressive, immunologically ‘cold’ tumor for which there are currently no approved therapies worldwide,” Charles Cai, MD, PhD, chief medical officer of Leads Biolabs, stated in the news release.
The agent has been evaluated across 13 solid tumor indications in China, comprising 1 pivotal registration trial and 8 proof-of-concept studies.
Opamtistomig is a bispecific antibody that simultaneously targets PD-L1 and the costimulatory receptor 4-1BB, developed using the X-Body bispecific platform. The agent is designed to block PD-1/PD-L1–mediated immune suppression and conditionally activate 4-1BB agonist signaling, an approach intended to produce a synergistic antitumor immune response. 4-1BB agonism can reactivate exhausted T cells and promote T-cell proliferation, offering a potential mechanism against PD-1/PD-L1–resistant tumors.
Opamtistomig has received several regulatory designations across its development, including
The most detailed clinical data for opamtistomig in EP-NEC come from an ongoing phase 1/2 trial (NCT05170958) evaluating the agent in patients with advanced malignant tumors and neuroendocrine carcinoma.² Findings presented at the
Among patients with EP-NEC treated across the study, the median duration of response was 5.3 months, and the median progression-free survival was 2.8 months. The median overall survival (OS) was not reached at a median follow-up of 8.5 months, with a 6-month OS rate of 61.7% in the overall population.
The phase 1/2 trial enrolled patients at least 18 years with advanced malignant tumors who had progressed on prior standard-of-care therapy and had an ECOG performance status of 0 or 1. In the phase 2b portion, patients were required to have centrally confirmed EP-NEC and to have received at least 2 prior lines of chemotherapy; ORR by independent review committee assessment served as the primary end point.
