Leads Biolabs' Opamtistomig (LBL-024) Enrolls First ESCC Patient, Exploring Dual PD-L1/4-1BB Mechanism for Superior Survival Benefits in China's High-Incidence Cancer

NANJING, China, March 9, 2026 /PRNewswire/ -- 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.

Executive Commentary
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."

About ESCC
China is a region with a high incidence of esophageal cancer, accounting for approximately 50% of the newly diagnosed and fatal cases of esophageal cancer worldwide. Esophageal cancer is broadly classified into ESCC and esophageal adenocarcinoma, of which squamous cell carcinoma represents the predominant subtype in China. According to 2022 data published by the International Agency for Research on Cancer (IARC) of the World Health Organization, ESCC ranked seventh among all cancers in China in terms of incidence, with an estimated 224,000 new cases and approximately 187,000 deaths recorded annually. Early-stage esophageal cancer typically presents with no obvious clinical symptoms, and the majority of patients are diagnosed at a locally advanced stage or with distant metastases. As a result, prognosis remains poor, with a five-year survival rate of only 10.0% to 30.0%.

About Opamtistomig (LBL-024)
Opamtistomig (LBL-024) is a potential first-in-class bispecific antibody that simultaneously targets PD-L1 and the co-stimulatory receptor 4-1BB. It is the first 4-1BB–targeting bispecific antibody globally to advance to a single-arm pivotal trial as monotherapy, and it holds promise to become the first approved therapy specifically for extrapulmonary neuroendocrine carcinoma (EP-NEC)—a rare malignancy with substantial unmet clinical need.

Developed using Leads Biolabs' proprietary X-Body bispecific platform, Opamtistomig features a 2:2 molecular format, incorporating two binding domains each for PD-L1 and 4-1BB with an optimized affinity ratio. This unique design enables dual functionality: reversing PD-L1–mediated immune suppression while selectively enhancing T-cell activation, resulting in a potent and synergistic anti-tumor immune response.

In two ongoing clinical studies in China, Opamtistomig has demonstrated promising efficacy and a favorable safety profile in patients with advanced EP-NEC, both as monotherapy and in combination with chemotherapy. Given the absence of a globally accepted standard of care for EP-NEC, these results support the advancement of a single-arm pivotal study toward potential accelerated approval.

Recognizing its clinical potential, Opamtistomig received Breakthrough Therapy Designation (BTD) from China's National Medical Products Administration (NMPA) in October 2024, and Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA) for the treatment of neuroendocrine carcinoma in November 2024. Additionally, in January 2026, Opamtistomig was granted Fast Track Designation (FTD) by the FDA and ODD by the European Commission for the treatment of EP-NEC, further underscoring its potential to address unmet medical needs in this patient population.

Mechanistically, 4-1BB agonism can reactivate exhausted T cells and promote robust T-cell proliferation, offering significant promise for PD-1/PD-L1–resistant or immunologically "cold" tumors. Beyond EP-NEC, Opamtistomig has received clinical trial approvals across multiple tumor types with high unmet medical needs, including small cell lung cancer (SCLC), biliary tract cancer (BTC), ovarian cancer (OC), non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), gastric cancer (GC), triple-negative breast cancer (TNBC), and malignant melanoma. Encouraging clinical activity has already been observed in NSCLC, SCLC, BTC, OC, and other indications, underscoring Opamtistomig's potential as a broad-spectrum immuno-oncology therapy.

About Leads Biolabs
Founded in 2012, Leads Biolabs is a clinical-stage biotechnology company dedicated to the discovery, development, and commercialization of innovative therapies to address underserved medical needs in oncology, autoimmune, and other severe diseases both in China and globally.

We are a front-runner in next-generation immuno-oncology treatments with a differentiated pipeline of 14 innovative drug candidates, including seven clinical-stage drug candidates, of which four lead products are among the top-tier clinically advanced candidates globally.

We adopt a science-driven R&D approach and have successfully established comprehensive R&D capabilities spanning antibody discovery and engineering, in vivo and in vitro efficacy evaluation, as well as druggability assessment. We have also developed multiple proprietary technology platforms, including LeadsBody platform (a CD3 T-cell engager platform), X-body platform (a 4-1BB engager platform), TOPiKinectics (ADC platform), which serve as the cornerstone for our continued innovation and have been validated by the clinical outcomes of our bispecific antibody portfolios.

We have established integrated capabilities across early discovery, translational medicine, clinical development, CMC and business development. The innovative nature and competitive strengths of our drug candidates, coupled with our global perspectives, proactive strategy, and efficient clinical validation, have made us an attractive partner for leading industry players and investment institutions. For more information, please visit https://en.leadsbiolabs.com/

SOURCE Leads Biolabs