Leads Biolabs’ Opamtistomig (PD-L1/4-1BB Bispecific Antibody) Phase II Clinical Study for First-Line Treatment of Esophageal Squamous Cell Carcinoma Advances to Expansion Stage

NANJING, China, Aug. 24, 2026 (GLOBE NEWSWIRE) -- Nanjing Leads Biolabs Co., Ltd. (“Leads Biolabs” or the “Company,” Stock Code: 9887.HK) today announced that Opamtistomig (LBL-024), the Company’s proprietary PD-L1/4-1BB bispecific antibody, as a first-line treatment for locally advanced or metastatic esophageal squamous cell carcinoma (ESCC), has completed its safety run‑in assessment and advanced to the expansion phase based on encouraging efficacy signals and a favorable safety profile.

The study is led by Professor Shen Lin of Peking University Cancer Hospital. In the safety run‑in stage, Opamtistomig in combination with chemotherapy demonstrated encouraging efficacy signals in patients with ESCC receiving first-line treatment, with a favorable overall safety and tolerability profile. Based on these findings and a comprehensive evaluation by the sponsor and investigators, the study has advanced to the combination therapy expansion phase.

This expansion phase is designed as a randomized controlled trial to conduct a head‑to‑head comparison of Opamtistomig plus chemotherapy versus tislelizumab plus chemotherapy as first‑line therapy for ESCC, aiming to further improve clinical outcomes over the current standard of care.

Opamtistomig is currently being evaluated in 11 clinical studies, including one pivotal single-arm registrational study, one confirmatory Phase III clinical study and nine proof-of-concept (“POC”) studies. To date, patient enrollment has been completed in three POC studies in first-line extrapulmonary neuroendocrine carcinoma (EP-NEC), small cell lung cancer (SCLC) and biliary tract cancer (BTC), of which the first-line EP-NEC program has advanced into confirmatory Phase III clinical development. Two additional POC studies in hepatocellular carcinoma (HCC) and ESCC have advanced to the expansion stage, further validating Opamtistomig’s pan‑tumor efficacy potential. Opamtistomig has demonstrated encouraging and durable efficacy signals across multiple indications. Clinical data from the first seven indications have demonstrated robust antitumor activity, while maintaining a favorable safety profile and good tolerability in approximately 800 patients, supporting its continued development as a potential next-generation immuno-oncology backbone therapy.

Executive Commentary
Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, commented: “Advancing this Phase II study of Opamtistomig in first‑line ESCC into the expansion phase is an important milestone in validating its potential as a next‑generation immuno‑oncology backbone therapy. While ESCC remains a significant disease burden, and despite advances in first-line treatment, patients continue to face substantial unmet medical needs. The encouraging efficacy signals and favorable safety profile observed with Opamtistomig in combination with chemotherapy during the safety run‑in provide further confidence in its potential to improve treatment outcomes for patients with ESCC. We will continue to accelerate clinical development to bring this innovative therapy to patients as quickly as possible.”

About ESCC
China is a high-incidence region for esophageal cancer, accounting for approximately half of the new cases and deaths from esophageal cancer globally. Esophageal cancer is primarily classified into ESCC and esophageal adenocarcinoma, with ESCC being the predominant histological subtype in China. According to data from the International Agency for Research on Cancer (IARC) in 2022, ESCC ranks seventh in cancer incidence in China, with approximately 224,000 new cases and 187,000 deaths annually. ESCC is often diagnosed at a locally advanced or metastatic stage and is associated with a poor prognosis. Although immune checkpoint inhibitors in combination with chemotherapy have improved objective response rate (ORR), progression-free survival (PFS) and overall survival (OS), median OS remains approximately 12 to 17 months and the five-year survival rate is approximately 10.0% to 30.0%. These limitations of existing therapies highlight a significant unmet medical need for more effective and durable treatment options.

About Opamtistomig
Opamtistomig (LBL-024) is emerging as a next-generation pan-cancer backbone therapy with potential overall survival (OS) benefit that simultaneously targets PD-L1 and the co-stimulatory receptor 4-1BB. Developed using Leads Biolabs’ proprietary X-Body bispecific platform, Opamtistomig is designed to simultaneously block PD-1/L1 immune suppression and conditionally activate 4-1BB, an agonist pathway, resulting in a potent and synergistic anti-tumor immune response. It has a safety profile comparable to PD-1/PD-L1 inhibitors and demonstrates broader-spectrum anti-cancer potential. To date, Opamtistomig has demonstrated first- or best-in-class potential in Phase II or registrational clinical trials across multiple indications, including non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), biliary tract cancer (BTC), and extrapulmonary neuroendocrine carcinoma (EP-NEC).

As the first 4-1BB–targeting bispecific antibody globally to advance to a single-arm pivotal trial as monotherapy, Opamtistomig has been evaluated in 13 solid tumor indications in China, including 1 pivotal registration trial and 8 proof-of-concept studies. These cover EP-NEC, NSCLC, SCLC, BTC, ovarian cancer (OC), esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), gastric cancer (GC), triple-negative breast cancer (TNBC), malignant melanoma, and other areas with high unmet medical needs.

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, and has the potential to deliver durable, long-tail survival benefits. 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.

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.

Leads Biolabs is a front-runner in next-generation immuno-oncology treatments with a differentiated pipeline of 14 innovative drug candidates, including five clinical-stage drug candidates and one registration-stage asset.

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

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