Leads Biolabs' Opamtistomig (PD-L1/4-1BB Bispecific Antibody) Advances to Expansion Phase in First-Line Biliary Tract Cancer Following Positive Safety and Preliminary Efficacy Results

Nanjing, China - April 8, 2026 - Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) announced that its proprietary PD-L1/4-1BB bispecific antibody, Opamtistomig (LBL-024), has successfully completed the safety run-in stage of a Phase II clinical trial in the first-line treatment of advanced biliary tract cancer (BTC). Based on favorable safety and encouraging preliminary efficacy data, the study has progressed into the expansion phase, with the first patient already enrolled.

The study is led by Dr. Jian Zhou from Zhongshan Hospital, Fudan University, and is being conducted across multiple clinical sites in China. A total of 20 patients were included in the safety run-in cohort and completed preliminary evaluation. Results demonstrated that Opamtistomig in combination with chemotherapy was generally well tolerated, with a favorable safety profile and no new safety signals observed. Preliminary efficacy assessments indicated encouraging tumor reduction trends. Based on these results, the study has advanced to the expansion phase with accelerated enrollment underway.

Opamtistomig is a uniquely engineered bispecific antibody designed to simultaneously block PD-1/L1-mediated immune suppression and selectively activate the 4-1BB co-stimulatory pathway. By restoring T-cell functionality and expanding effector T-cell populations within the tumor microenvironment, Opamtistomig has the potential to deliver more potent and durable anti-tumor activity than PD-1/PD-L1 blockade alone, particularly in difficult-to-treat and immunotherapy-resistant tumors. To date, Opamtistomig has demonstrated first- or best-in-class potential in Phase II or registrational clinical trials across three indications: non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and extrapulmonary neuroendocrine carcinoma (EP-NEC).

Executive Commentary

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, commented:" Based on favorable safety and encouraging efficacy signals from the safety run-in cohort, Opamtistomig has advanced into the expansion phase of the Phase II BTC study, with strong support from investigators unanimously. This represents an important milestone for the program and reinforces our confidence in its clinical potential. As additional efficacy data mature, we plan to initiate a confirmatory study, leveraging our extensive clinical network to accelerate development and bring a differentiated immunotherapy option to patients with advanced biliary tract cancer as early as possible."

About Biliary Tract Cancer

Biliary tract malignancies primarily include gallbladder cancer and intrahepatic/extrahepatic cholangiocarcinoma, with approximately 419,100 new cases globally in 2024. These malignancies are predominantly adenocarcinomas with high invasiveness, and most cases are diagnosed at advanced stages, leading to poor prognosis (5-year survival rate



This release was published on openPR.