NANJING, China, October 16, 2026
Nanjing Leads Biolabs Co., Ltd. (HKEX: 9887) announced that the first patient has been dosed in an open-label, multicenter Phase Ib/II clinical trial evaluating opamtistomig (LBL-024), an investigational PD-L1/4-1BB bispecific antibody, in combination therapy for metastatic colorectal cancer (mCRC). The trial expands the company’s strategy to develop immunotherapies for immunologically cold tumors, which typically show limited responses to conventional immune checkpoint inhibitors. The program focuses on a substantial unmet medical need among patients with microsatellite-stable (MSS) or mismatch repair-proficient (pMMR) colorectal cancer, who account for approximately 95% of cases according to the company. Opamtistomig is designed to combine PD-L1 blockade with conditional activation of 4-1BB, a receptor involved in T-cell activation, with the aim of enhancing antitumor immune responses. Led by Academician Xu Ruihua of Sun Yat-sen University Cancer Center, the study will be conducted across multiple hospitals in China to evaluate the candidate’s safety and efficacy in combination therapy. Leads Biolabs said translational research involving opamtistomig in MSS colorectal cancer has also been selected for poster presentation at the 2026 European Society for Medical Oncology (ESMO) Congress. The candidate remains investigational for mCRC, and its clinical benefit in this indication has yet to be established.
Bispecific Mechanism Targets Immunologically Cold Tumors
Opamtistomig is designed to address two mechanisms relevant to antitumor immunity. Its PD-L1-blocking component is intended to relieve immunosuppressive signaling, while conditional activation of 4-1BB is designed to stimulate and expand T cells involved in immune responses against tumors. The company aims to use this dual mechanism to improve immune activity in tumors that have limited T-cell infiltration and respond poorly to conventional checkpoint inhibitors. This approach is particularly relevant to MSS/pMMR colorectal cancer, where existing immunotherapy options have had limited effectiveness compared with those available for microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) disease. Leads Biolabs Chief Medical Officer Dr. Charles Cai said the combination of PD-L1 blockade and conditional 4-1BB activation represents a differentiated strategy for immunologically cold tumors. He cited translational research in MSS colorectal cancer and clinical findings across other tumor types as the basis for further evaluating opamtistomig. The ongoing Phase Ib/II trial will provide additional evidence regarding the safety and antitumor activity of the candidate when administered in combination with other therapy. The company has not disclosed detailed enrollment targets, specific combination partners or a projected completion date in the announcement
Phase Ib/II Study Expands Clinical Evaluation
The multicenter, open-label Phase Ib/II trial is intended to evaluate the safety and efficacy of opamtistomig combination therapy in metastatic colorectal cancer. Academician Xu Ruihua of Sun Yat-sen University Cancer Center is leading the study, which will run concurrently across multiple hospitals nationwide in China. The program builds on the candidate’s clinical development in other tumor types, including extrapulmonary neuroendocrine carcinoma (EP-NEC), biliary tract cancer (BTC), hepatocellular carcinoma (HCC) and platinum-resistant ovarian cancer (PROC). According to Leads Biolabs, opamtistomig has shown a trend toward prolonged survival compared with historical data across these indications. Such comparisons are preliminary and do not establish superiority over standard treatments; further controlled clinical evidence is needed to determine the candidate’s therapeutic value. The company also reported that a translational medicine study examining opamtistomig in MSS colorectal cancer was selected for poster presentation at the 2026 ESMO Congress. Together, the trial and translational research are intended to support evaluation of the drug’s biological activity and potential role in a patient population with limited immunotherapy responsiveness.
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High Unmet Need in Metastatic Colorectal Cancer
Colorectal cancer remains a major global health burden. According to figures cited by Leads Biolabs from the International Agency for Research on Cancer, approximately 1.93 million new cases and 904,000 deaths occurred worldwide in 2022. In China, National Cancer Center data cited in the announcement recorded approximately 517,000 new cases and 240,000 deaths that year. The company noted that approximately 15%–30% of patients have metastatic disease at initial diagnosis, while 20%–50% of patients initially diagnosed with localized disease eventually develop metastases. Although treatment options have advanced, metastatic colorectal cancer continues to carry a poor prognosis, with the announcement citing an approximate five-year survival rate of 15%. Current immunotherapy approaches are primarily used in patients with MSI-H or dMMR disease, a minority of cases. The much larger MSS/pMMR population generally responds poorly to conventional immune checkpoint inhibitors, leaving a significant need for alternative strategies. Leads Biolabs is evaluating whether opamtistomig’s combined immune-modulating mechanism can address this gap. The Phase Ib/II study marks an early clinical step toward determining whether the approach can deliver meaningful benefits for patients with metastatic colorectal cancer..
Source::: Leads Biolabs,,press release
