On 8 April 2026, Nanjing Leads Biolabs Co., Ltd. (Leads Biolabs) reported that its Phase II clinical study of Opamtistomig (LBL-024), a PD-L1/4-1BB bispecific antibody, for first-line treatment of advanced biliary tract cancer (BTC) has progressed from the safety run-in to the expansion phase. The first patient in the expansion cohort has already been enrolled.

During the safety run-in, 20 participants across multiple hospitals in China completed initial assessments. Combination therapy of LBL-024 with chemotherapy exhibited a favourable safety profile with no new signals and showed an early trend of tumour shrinkage, supporting the transition to an accelerated expansion phase. The trial is led by Academician Zhou Jian of Zhongshan Hospital, Fudan University.

BTC, encompassing gallbladder cancer and intra-/extrahepatic cholangiocarcinoma, registered about 419,100 new global cases in 2024. With most patients diagnosed at advanced stages, the five-year survival rate remains below 5%. Current PD-1/PD-L1 inhibitor regimens have raised median overall survival from 11.5 months to 12.8 months and maintain objective response rates under 30%, underscoring a continued high unmet medical need.

LBL-024 targets both PD-L1 and the co-stimulatory receptor 4-1BB, aiming to relieve PD-1/L1-mediated immunosuppression while activating T-cells. Built on the company’s proprietary X-body® platform with a 2:2 structural design, the molecule is also under investigation in non-small cell lung cancer, small cell lung cancer and extrapulmonary neuroendocrine carcinoma (EP-NEC), where it has shown first-in-class or best-in-class potential. Regulatory designations already include Breakthrough Therapy (China), Orphan Drug (US FDA, EC) and Fast Track (US FDA) status for EP-NEC.

Leads Biolabs cautions that development and commercialisation of LBL-024 are subject to ongoing clinical and regulatory outcomes.