Nanjing Leads Biolabs Co, Ltd (9887.HK) announced on Thursday that it has completed patient enrollment in its pivotal single-arm registrational trial (CTR20213023) evaluating Opamtistomig (LBL-024) monotherapy for extrapulmonary neuroendocrine carcinoma (EP-NEC). This is the first global registrational study of an immunotherapy monotherapy for EP-NEC, led by Professor Shen Lin of Peking University Cancer Hospital across multiple centres in China.

The study targets patients with advanced EP-NEC who have failed at least two lines of chemotherapy. EP-NEC is a rare, aggressive, immunologically 'cold' tumour with no established second-line standard of care, underscoring significant unmet need.

Opamtistomig, developed using the company's X-Body bispecific platform, is a first-in-class PD-L1/4-1BB bispecific antibody. Its dual mechanism both reverses PD-L1-mediated immune suppression and selectively activates T cells, aiming to deliver synergistic anti-tumour effects. Phase I/II trials in China have shown encouraging efficacy and safety in EP-NEC, supporting the pursuit of accelerated approval.

Regulatory milestones include Breakthrough Therapy Designation from China's National Medical Products Administration in October 2024 and Orphan Drug Designation from the U.S. Food and Drug Administration in November 2024. Beyond EP-NEC, the therapy is in clinical trials for multiple high-need cancers including small cell lung cancer, biliary tract cancer, ovarian cancer and gastric cancer, with early signs of broad-spectrum oncology potential.