Leads Biolabs' PD-L1/4-1BB Bispecific Opamtistomig Wins Japanese Orphan Drug Designation for EP-NEC
核心洞察
Japan's Ministry of Health, Labour and Welfare granted orphan drug designation to opamtistomig (搜索) (LBL-024) for extrapulmonary neuroendocrine carcinoma (搜索), the antibody's third such designation globally.
The designation follows orphan status from the U.S. FDA and European Commission, plus FDA Fast Track and China NMPA Breakthrough Therapy Designation for the PD-L1 (搜索)/4-1BB (搜索) bispecific.
Opamtistomig (搜索) is being evaluated in 14 indications, including one pivotal single-arm registrational study, one confirmatory Phase III trial and nine proof-of-concept studies.
Nanjing Leads Biolabs (搜索) announced that opamtistomig (搜索) (LBL-024), its proprietary PD-L1 (搜索)/4-1BB (搜索) bispecific antibody, has been granted Orphan Drug Designation by Japan's Ministry of Health, Labour and Welfare for the treatment of extrapulmonary neuroendocrine carcinoma (搜索) (EP-NEC). The designation is the third orphan status awarded to the candidate, following designations from the U.S. Food and Drug Administration (搜索) and the European Commission, and extends its regulatory recognition into a major Asian market.
Under the designation, opamtistomig (搜索) gains access to Japanese regulatory and development incentives that may include financial support and subsidies for clinical development, regulatory consultation and advice from the MHLW and other relevant authorities, potential access to priority consultation and expedited review pathways, reduction or exemption of certain application and examination fees, and an extended re-examination period following marketing authorization. Leads Biolabs (搜索) said these incentives are expected to facilitate and potentially accelerate clinical development, regulatory submission and commercialization in Japan, particularly for EP-NEC and other high-potential indications.
Japan's pharmaceutical market exceeded $73 billion in 2025, with the immuno-oncology segment accounting for more than $8 billion, ranking behind only the United States, China and Europe, according to the company. Leads Biolabs (搜索) stated that securing orphan drug designation in this market establishes priority consultation and accelerated review pathways within Japan's regulatory framework for subsequent development and registration of opamtistomig (搜索) in other tumor indications.
Regulatory Timeline Across Four Markets
Opamtistomig (搜索) has accumulated designations in China, the United States, Europe and now Japan. It received Breakthrough Therapy Designation from China's National Medical Products Administration (搜索) in October 2024, and Orphan Drug Designation from the U.S. FDA in November 2024. In January 2026, the FDA granted Fast Track Designation and the European Commission granted Orphan Drug Designation. In July 2026, the NMPA granted priority review to the New Drug Application, and the NDA was accepted by the NMPA in August 2026 and is now under technical review.
Leads Biolabs (搜索) said the NDA acceptance positions opamtistomig (搜索) as a potential world's first approved 4-1BB (搜索)-targeting antibody, the first approved agonist antibody, and the first approved treatment for EP-NEC.
"The orphan drug designation in Japan represents an important milestone in the global development of opamtistomig (搜索) and further strengthens its regulatory recognition across the four key markets of China, the United States, Europe, and Japan," said Dr. Charles Cai, Chief Medical Officer of Leads Biolabs (搜索). "It underscores the innovative value and global development potential of opamtistomig, particularly in EP-NEC, a tumor type with substantial unmet medical needs."
Clinical Program and Mechanism
Opamtistomig (搜索) is being evaluated in 14 indications, comprising one pivotal single-arm registrational study, one confirmatory Phase III study and nine proof-of-concept studies, covering major indications such as non-small cell lung cancer (搜索) and multiple immunologically cold tumors. To date, the candidate has shown antitumor activity across seven tumor types: EP-NEC in first-line and post-line settings, NSCLC, small cell lung cancer (搜索), biliary tract cancer (搜索), hepatocellular carcinoma (搜索), esophageal squamous cell carcinoma (搜索) and ovarian cancer (搜索).
Clinical results from studies in EP-NEC, NSCLC and BTC have been presented at the American Society of Clinical Oncology Annual Meeting, the World Conference on Lung Cancer and the European Society for Medical Oncology Annual Congress.
Developed on Leads Biolabs (搜索)' proprietary X-Body bispecific platform, opamtistomig (搜索) is designed to simultaneously block PD-1/PD-L1 (搜索) immune suppression and conditionally activate 4-1BB (搜索), an agonist pathway, to produce a synergistic anti-tumor immune response. The company reports a safety profile comparable to PD-1/PD-L1 inhibitors. Mechanistically, 4-1BB agonism can reactivate exhausted T cells and promote T-cell proliferation, a rationale the company applies to PD-1/PD-L1-resistant or immunologically cold tumors.
Leads Biolabs (搜索), founded in 2012, is a clinical-stage biotechnology company focused on oncology, autoimmune and other severe diseases. Its pipeline includes 15 innovative drug candidates, of which five are clinical-stage and one is a registration-stage asset. The company's technology platforms include LeadsBody, a CD3 T-cell engager platform; X-body, a 4-1BB (搜索) engager platform; TOPiKinectics, an ADC platform; and ImBiTDC, a TDC platform.