Leads Biolabs' Opamtistomig NDA Accepted by China's NMPA for Rare Neuroendocrine Cancer

China's National Medical Products Administration (NMPA) has accepted the new drug application (NDA) for opamtistomig (LBL-024), Leads Biolabs' programmed cell death ligand 1 (PD-L1)/4-1BB bispecific antibody, as a monotherapy for previously treated advanced extrapulmonary neuroendocrine carcinoma (EP-NEC), the company announced August 21, 2026.¹ Opamtistomig is the first PD-L1/4-1BB bispecific antibody globally to enter NDA review and received priority review from China's Center for Drug Evaluation (CDE) on July 10, 2026, according to the company.¹

"The acceptance of Opamtistomig's NDA marks a major milestone in our mission to develop differentiated immunotherapies for patients with high unmet medical needs," said Charles Cai, MD, chief medical officer of Leads Biolabs, in a company press release.¹ "As the first 4-1BB-targeting bispecific antibody globally to advance into registrational clinical development, Opamtistomig represents a significant breakthrough in the treatment of EP-NEC, a highly aggressive, immunologically 'cold' tumor for which there are currently no approved therapies worldwide."

Why is a new treatment needed for EP-NEC?

EP-NEC is a highly aggressive, immunologically "cold" subtype of neuroendocrine carcinoma with no therapies specifically approved in any world region.¹ First-line treatment relies on platinum-based chemotherapy, with an objective response rate of about 30% to 50% and median overall survival of roughly 1 year; no standard second-line therapy exists, and available second-line options have an objective response rate of only about 10% to 25% and median overall survival of about 8 months.¹

What clinical evidence supports the NDA?

The NDA is supported by a registrational trial led by Professor Shen Lin of Peking University Cancer Hospital, conducted across 34 sites, which completed enrollment of 96 patients with EP-NEC in August 2025. Detailed results are planned for presentation at an international medical congress.¹

Earlier data from opamtistomig's phase 1b/2 trial combining the drug with etoposide/platinum chemotherapy in treatment-naive advanced EP-NEC, presented at the 2025 ASCO Annual Meeting, showed treatment-related adverse events in all 53 evaluable patients, with grade 3 or higher events in 17 patients (32.1%).² Earlier monotherapy data from opamtistomig's first-in-human trial showed a 33.3% objective response rate and 51.1% disease control rate at the recommended phase 2 dose of 15 mg/kg in patients with EP-NEC.³

How does opamtistomig work, and what would approval mean?

Opamtistomig is designed to simultaneously block programmed cell death protein 1 (PD-1)/PD-L1-mediated immune suppression and activate 4-1BB, a co-stimulatory receptor that can reactivate exhausted T cells, intended to produce a synergistic anti-tumor immune response particularly in PD-1/PD-L1-resistant or immunologically cold tumors.¹ If approved, opamtistomig would become the world's first approved antibody directly targeting 4-1BB and the first approved agonistic antibody, making 4-1BB the fourth immuno-oncology target with an approved therapy worldwide, following PD-1/PD-L1, CTLA-4, and LAG-3.¹ Opamtistomig has also received breakthrough therapy designation and orphan drug designation from FDA, and orphan drug designation from the European Medicines Agency.¹

What's next for Leads Biolabs' broader pipeline?

Beyond EP-NEC, Leads Biolabs is advancing opamtistomig across non-small cell lung cancer, biliary tract cancer, hepatocellular carcinoma, esophageal squamous cell carcinoma, and ovarian cancer, with clinical data generated across 7 indications to date. The company's pipeline includes 14 drug candidates, including 5 clinical-stage candidates and 1 registration-stage asset, built on proprietary platforms including its X-Body bispecific antibody technology.¹

What are the limitations?

NDA acceptance does not guarantee approval, and the pivotal 96-patient trial's detailed results have not yet been presented or published. Data cited from the phase 1b/2 combination trial come from a different, earlier-line treatment setting (treatment-naive, chemotherapy-combination) than the monotherapy indication now under NDA review.

References

1. Nanjing Leads Biolabs. Leads Biolabs' Opamtistomig (PD-L1/4-1BB bispecific antibody) NDA accepted by NMPA, poised to become world's first approved 4-1BB-targeting therapy. News release. Published August 21, 2026. Accessed August 21, 2026. https://prnmedia.prnewswire.com/news-releases/leads-biolabs-opamtistomig-pd-l14-1bb-bispecific-antibody-nda-accepted-by-nmpa-poised-to-become-worlds-first-approved-4-1bb-targeting-therapy-302857237.html
2. Lu M, Zhang P, Liu B, et al. Assessment of efficacy of LBL-024, a novel and uniquely designed bispecific antibody against PD-L1 and 4-1BB, combined with etoposide/platinum-based chemotherapy in treatment-naive advanced extrapulmonary neuroendocrine carcinoma (EP-NEC): a multicenter phase Ib/II trial. J Clin Oncol. 2025;43(16_suppl):2500. doi:10.1200/JCO.2025.43.16_suppl.2500
3. Lu M, Zhang P, Luo S, et al. A novel and uniquely designed bispecific antibody (LBL-024) against PD-L1 and 4-1BB in patients with advanced malignant tumors and neuroendocrine carcinoma: a report of safety and robust efficacy of LBL-024 monotherapy in phase I/II, first-in-human, open-label, multicenter, dose escalation/expansion study. J Clin Oncol. 2024;42(16_suppl):4010. doi:10.1200/JCO.2024.42.16_suppl.4