NANJING, China — August 25, 2026
Leads Biolabs announced that its proprietary Opamtistomig (LBL-024), a PD-L1/4-1BB bispecific antibody, has advanced into the expansion stage of a Phase II clinical study evaluating the candidate as a first-line treatment for patients with locally advanced or metastatic esophageal squamous cell carcinoma (ESCC). The company said the study completed its safety run-in based on encouraging efficacy signals and a favorable safety and tolerability profile observed with Opamtistomig combined with chemotherapy. The expansion represents an important step in the clinical development of the investigational immuno-oncology therapy and will further evaluate its potential in a disease setting where treatment options remain limited.
Randomized Expansion to Compare Opamtistomig With Current Therapy
The next stage of the Phase II ESCC study is designed as a randomized controlled trial comparing Opamtistomig plus chemotherapy directly with tislelizumab plus chemotherapy in the first-line setting. This head-to-head design is intended to determine whether the PD-L1/4-1BB bispecific approach can deliver improved clinical outcomes compared with an established immunotherapy-based treatment regimen. The study is led by Professor Shen Lin of Peking University Cancer Hospital, and the decision to advance follows evaluation of the safety run-in by the company and investigators. The expansion-stage data will therefore be important in determining whether the early efficacy signals translate into a stronger and more durable treatment benefit in a larger patient population. For cGxP.wire readers, the key development is the transition from initial safety assessment to a randomized expansion designed to generate comparative clinical evidence.
Opamtistomig Pipeline Expands Across Multiple Cancer Types
The ESCC program is part of a broader clinical development strategy for Opamtistomig, which is currently being evaluated in 11 clinical studies, including a pivotal single-arm registrational study, a confirmatory Phase III study and nine proof-of-concept programs. According to Leads Biolabs, three POC studies have completed patient enrollment in first-line extrapulmonary neuroendocrine carcinoma, small cell lung cancer and biliary tract cancer, with the EP-NEC program already advancing into confirmatory Phase III development. Programs in hepatocellular carcinoma and ESCC have also progressed into expansion stages. The company reported that clinical data from the first seven indications have shown encouraging antitumor activity, while safety and tolerability have remained favorable across approximately 800 treated patients. These developments position Opamtistomig as a potential next-generation immuno-oncology backbone, with the company continuing to evaluate its activity across different tumor types and treatment settings.
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ESCC Program Targets Significant Unmet Treatment Need
The advancement of the Opamtistomig study comes against a substantial disease burden in esophageal squamous cell carcinoma, particularly in China, where ESCC represents the predominant histological subtype of esophageal cancer. Despite improvements from immune checkpoint inhibitors combined with chemotherapy, patients with locally advanced or metastatic disease continue to face limited long-term outcomes. Leads Biolabs is therefore evaluating whether combining PD-L1 blockade with 4-1BB activation through a single bispecific antibody can provide a differentiated therapeutic approach. The company’s latest milestone does not yet establish superiority over tislelizumab, as the randomized expansion is intended to generate that comparative evidence. Nevertheless, the move into the expansion stage marks a meaningful clinical development milestone for Opamtistomig in first-line ESCC and provides a clearer path toward evaluating its potential role in future immuno-oncology treatment strategies.
Source:Leads Biolabs press relese
