NANJING, China — September 28, 2026
Leads Biolabs announced that opamtistomig (LBL-024), its investigational PD-L1/4-1BB bispecific antibody, has received Orphan Drug Designation (ODD) from Japan’s Ministry of Health, Labour and Welfare (MHLW) for the treatment of extrapulmonary neuroendocrine carcinoma (EP-NEC). The designation represents the third orphan drug designation for opamtistomig, following previous designations from the U.S. Food and Drug Administration (FDA) and the European Commission (EC). Leads Biolabs said the Japanese designation provides access to regulatory and development incentives that may support the clinical development and potential registration of opamtistomig in Japan. The company is developing the bispecific antibody across multiple solid-tumor indications, with EP-NEC among the indications being evaluated in its global clinical development program.
Japan ODD Provides Development and Regulatory Incentives
Japan’s orphan drug framework can provide designated therapies with a range of development and regulatory incentives, which may include financial support for clinical development, regulatory consultation, priority consultation and potentially expedited review pathways, as applicable. Certain application and examination fees may also be reduced or exempted, while an extended re-examination period may be available following marketing authorization. Leads Biolabs said these measures could help facilitate development and regulatory submission of opamtistomig for EP-NEC in Japan. The company also views the designation as an opportunity to establish a regulatory pathway for evaluating the candidate in additional tumor indications. The Japanese ODD does not constitute marketing approval or establish the safety or efficacy of opamtistomig, and further clinical and regulatory review will be required before any potential authorization.
Opamtistomig Advances Global Regulatory Development
The Japan designation adds to a series of regulatory milestones achieved by opamtistomig across major pharmaceutical markets. Since October 2024, the candidate has received Breakthrough Therapy Designation from China’s NMPA, along with U.S. FDA Orphan Drug and Fast Track designations and European Commission Orphan Drug Designation. Leads Biolabs also reported that its New Drug Application for opamtistomig received Priority Review from the NMPA in July 2026, followed by an NDA submission in August that is currently under technical review. The company is evaluating opamtistomig across seven tumor types, including EP-NEC, non-small cell lung cancer, small cell lung cancer, biliary tract cancer, hepatocellular carcinoma, esophageal squamous cell carcinoma and ovarian cancer. Clinical findings from several studies have been presented at major oncology meetings including ASCO, WCLC and ESMO.
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Leads Biolabs Expands PD-L1/4-1BB Development Strategy
Opamtistomig is designed to combine PD-L1 targeting with 4-1BB immune activation in a single bispecific antibody, forming the basis of Leads Biolabs’ immuno-oncology development strategy. The company has reported efficacy signals across multiple tumor types and described the candidate as a potential next-generation immuno-oncology backbone, although these findings remain subject to ongoing clinical evaluation. In EP-NEC, a rare and difficult-to-treat tumor type, the Japanese orphan designation provides a regulatory development framework as the company advances the candidate toward potential registration. Leads Biolabs said the designation further strengthens its development strategy across China, the United States, Europe and Japan, while potentially supporting future expansion into additional indications. Opamtistomig remains investigational, and continued clinical studies will be required to determine its safety, efficacy and potential role in cancer treatment.
Source : Leads Biolabs, press release
