NANJING, China, August 6, 2026
Leads Biolabs announced that its Phase II clinical study evaluating Opamtistomig (LBL-024) in combination with bevacizumab for the treatment of first-line hepatocellular carcinoma (HCC) has successfully completed the safety run-in phase and advanced into the expansion phase following expert review. The trial is led by Professor Zhou Jian, President of Zhongshan Hospital, Fudan University, and an Academician of the Chinese Academy of Sciences. Preliminary clinical findings demonstrated encouraging anti-tumor activity together with a favorable safety profile, supporting continued patient enrollment and broader clinical evaluation. The milestone further strengthens the development of Opamtistomig, the company’s proprietary PD-L1/4-1BB bispecific antibody, as a next-generation immunotherapy designed to improve outcomes for patients with advanced liver cancer who continue to face limited treatment options despite current standard-of-care therapies.
Positive Clinical Signals Support Phase II Expansion
The Phase II study is evaluating Opamtistomig combined with bevacizumab as a first-line treatment for hepatocellular carcinoma, one of the world’s most aggressive cancers. According to the company, preliminary results from the safety run-in phase showed promising efficacy signals alongside a manageable safety profile, allowing investigators to advance the study into the expansion stage. Current first-line treatment with PD-1/PD-L1 inhibitors plus bevacizumab has improved patient care but still delivers a median overall survival of only 19–20 months, progression-free survival below seven months, and objective response rates under 30%. These limitations highlight the continued need for more effective immunotherapy combinations capable of delivering longer-lasting responses and improved survival. The expansion phase will further evaluate the combination’s therapeutic potential in a broader patient population.
Bispecific Antibody Shows Broad Oncology Potential
Opamtistomig (LBL-024) is a proprietary PD-L1/4-1BB bispecific antibody developed using Leads Biolabs’ X-body™ platform, which is designed to activate the 4-1BB immune signaling pathway selectively within the tumor microenvironment, enhancing anti-tumor immune responses while minimizing systemic toxicity. Across nearly 800 treated patients, the investigational therapy has maintained a favorable safety profile while demonstrating encouraging activity in multiple solid tumors, including non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), extrapulmonary neuroendocrine carcinoma (EP-NEC), biliary tract cancer (BTC), and hepatocellular carcinoma. These results continue to support the company’s strategy of developing Opamtistomig as a next-generation IO 2.0 pan-tumor immunotherapy platform with broad application across several difficult-to-treat cancers.
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Program Strengthens Global Development Strategy
Leads Biolabs stated that advancing the HCC study into the expansion phase represents an important milestone in validating Opamtistomig’s differentiated mechanism of action and supports the company’s broader global clinical development and registration strategy. Chief Medical Officer Dr. Charles Cai noted that while PD-1/PD-L1-based therapies have become standard treatment for advanced HCC, substantial unmet medical needs remain due to limited long-term survival and response rates. The company believes the encouraging efficacy observed with Opamtistomig plus bevacizumab reinforces confidence in the therapy’s ability to improve patient outcomes and accelerate its global clinical development. With liver cancer remaining one of the leading causes of cancer-related mortality worldwide—particularly in China, where approximately 368,000 new HCC cases and 317,000 deaths occur annually—the continued advancement of innovative bispecific antibody immunotherapies may provide an important step toward expanding treatment options for patients with this devastating disease.
Source:Leads Biolabs press release
