NANJING, China, July 30, 2026
Leads Biolabs announced that its Phase II clinical trial evaluating Opamtistomig (LBL-024), a proprietary PD-L1/4-1BB bispecific antibody, for first-line advanced biliary tract cancer (BTC) has completed enrollment of all 70 patients. The study entered its expansion phase in April 2026 following encouraging safety and efficacy observations, enabling rapid patient recruitment across multiple clinical sites in China. The multicenter study is assessing Opamtistomig in combination with chemotherapy for patients with advanced BTC, an aggressive gastrointestinal malignancy with limited treatment options. The company believes the successful completion of enrollment marks another important milestone in advancing its IO 2.0 immuno-oncology platform and further strengthens its growing gastrointestinal oncology pipeline.
Opamtistomig Shows Strong Promise in Immune-Cold Tumors
BTC remains one of the most challenging immune-cold tumors, where currently approved PD-(L)1 inhibitor plus chemotherapy regimens have delivered objective response rates below 30% and median overall survival of approximately 12–13 months, highlighting significant unmet medical need. According to Leads Biolabs, Opamtistomig’s dual mechanism simultaneously blocks the PD-L1 immune checkpoint while conditionally activating the 4-1BB co-stimulatory pathway, restoring anti-tumor immune activity and enhancing T-cell function. Across multiple clinical programs, including small cell lung cancer (SCLC), extrapulmonary neuroendocrine carcinoma (EP-NEC), and now biliary tract cancer, the bispecific antibody has demonstrated encouraging anti-tumor activity, long-term survival potential, and a safety profile comparable to conventional PD-(L)1 monoclonal antibodies, positioning it as a potential pan-tumor immunotherapy candidate.
ESMO 2026 Data Presentation Planned Following Enrollment Completion
The Phase II study is led by Academician Zhou Jian of Zhongshan Hospital, Fudan University, with participation from multiple hospitals throughout China. Initial safety run-in data demonstrated a favorable safety profile, good tolerability, and no new safety signals, while preliminary efficacy analyses showed encouraging tumor shrinkage among treated patients. Leads Biolabs confirmed that detailed clinical findings from the completed Phase II trial will be presented during the European Society for Medical Oncology (ESMO) Annual Meeting 2026, scheduled for October 23–27 in Madrid, Spain. The company expects these data to provide further evidence supporting the clinical potential of Opamtistomig in difficult-to-treat gastrointestinal cancers and additional immune-cold tumor indications.
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Leads Biolabs Expands Next-Generation Immunotherapy Portfolio
Leads Biolabs continues to position Opamtistomig as a next-generation IO 2.0 bispecific immunotherapy with broad applications across multiple solid tumors. The company stated that encouraging efficacy observed in both adenocarcinoma and squamous cell carcinoma reinforces the therapy’s broad-spectrum anti-cancer potential. With enrollment now complete in the BTC trial and additional clinical studies ongoing across several gastrointestinal cancers, Leads Biolabs aims to accelerate development of innovative immunotherapies capable of overcoming resistance commonly seen in immune-cold tumors. If future clinical data continue to confirm these early findings, Opamtistomig could emerge as a differentiated treatment option for patients with advanced cancers where existing immunotherapy approaches have shown limited benefit.
Source: Leads Biolabs, press release
