Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) announced on March 6, 2026 that the first patient has been successfully dosed in a Phase Ⅱ clinical study evaluating Opamtistomig (LBL-024), the company's core investigational PD-L1/4-1BB bispecific antibody, for the first-line treatment of locally advanced or metastatic esophageal squamous cell carcinoma (ESCC).

ESCC ranks as the seventh most common cancer in China, characterized by insidious onset and poor prognosis. Although immune checkpoint inhibitors combined with chemotherapy have improved objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) compared to chemotherapy alone, median OS remains only 12-17 months. This underscores the limitations of current treatment approaches and the urgent need for improved outcomes, highlighting the necessity to explore more effective innovative strategies to address this significant clinical challenge.

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).

The open-label, multi-center Phase Ⅱ clinical study is led by Professor Shen Lin of Beijing Cancer Hospital and is being conducted across multiple hospitals in China. The trial aims to evaluate the efficacy and safety of Opamtistomig administered in patients with ESCC.

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, stated: "ESCC is highly prevalent with poor prognosis in China. While immune-chemotherapy combinations have shown progress, the overall survival benefit remains very limited, necessitating breakthrough solutions. The dosing of the first ESCC patient with Opamtistomig marks a critical milestone in our clinical strategy for this core pipeline asset. We anticipate it will overcome current immunotherapy limitations, delivering both higher response rates and prolonged survival benefits for patients."