Leads Biolabs' Opamtistomig (PD-L1/4-1BB Bispecific Antibody) NDA Accepted by NMPA, Poised to Become World's First Approved 4-1BB-Targeting Therapy

NANJING, China, Aug. 21, 2026 /PRNewswire/ -- Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) today announced the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA) has accepted the New Drug Application (NDA) for Opamtistomig (LBL-024), the Company's proprietary PD-L1/4-1BB bispecific antibody, as a monotherapy for the treatment of previously treated advanced extrapulmonary neuroendocrine carcinoma (EP-NEC).

Opamtistomig is the first PD-L1/4-1BB bispecific antibody globally to enter NDA review and was granted Priority Review by the CDE on July 10, 2026. If approved, Opamtistomig would become the world's first approved antibody drug directly targeting 4-1BB, as well as the first approved agonistic antibody. This milestone would also make 4-1BB the fourth immuno-oncology target worldwide with an approved therapy, following PD-1/PD-L1, CTLA-4 and LAG-3.

The NDA is supported by positive results from a registrational clinical study led by Professor Shen Lin of Peking University Cancer Hospital and conducted across 34 clinical sites. The study completed enrollment of 96 patients with EP-NEC in August 2025. Detailed results are planned for presentation at a leading international medical congress.

Executive Commentary

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, said: "The acceptance of Opamtistomig's NDA marks a major milestone in our mission to develop differentiated immunotherapies for patients with high unmet medical needs. Opamtistomig has received multiple regulatory designations that have accelerated its development, including Breakthrough Therapy Designation and Priority Review from China's CDE, Orphan Drug Designation and Fast Track designation from the U.S. FDA, and Orphan Drug Designation from the European Medicines Agency.

As the first 4-1BB-targeting bispecific antibody globally to advance into registrational clinical development, Opamtistomig represents a significant breakthrough in the treatment of EP-NEC, a highly aggressive, immunologically 'cold' tumor for which there are currently no approved therapies worldwide. Beyond EP-NEC, we are advancing our clinical program across multiple high-burden indications, including non‑small cell lung cancer, biliary tract cancer, hepatocellular carcinoma, esophageal squamous cell carcinoma, and ovarian cancer. Clinical data generated from seven indications have shown promising antitumor activities and support the broad therapeutic potential of Opamtistomig.

We believe Opamtistomig has the potential to become a cornerstone of next-generation immunotherapy and to establish a new paradigm for T-cell agonist development. The NDA acceptance represents an important validation of our differentiated approach and brings us one step closer to delivering a novel treatment option to patients with limited therapeutic alternatives."

Dr. Xiaoqiang Kang, Founder, Chairman, and CEO of Leads Biolabs, added: "The acceptance of Opamtistomig's NDA marks a critical step forward as Leads Biolabs transitions toward commercialization. Since our founding, we have deliberately moved beyond the highly competitive PD-1/PD-L1 space to pursue differentiated mechanisms and address areas of significant unmet medical needs, with 4-1BB representing one of the most promising frontiers in immuno-oncology.

Today, Opamtistomig stands poised to become the world's first approved 4-1BB-targeting drug. This achievement reflects our 14-year commitment to differentiated innovation and our determination to tackle some of the most challenging targets in oncology.

We are grateful to the patients, investigators, clinical research teams, regulatory authorities, and all our employees and partners who have contributed to the development of Opamtistomig. We will work closely with regulatory authorities throughout the review process to bring Opamtistomig to patients as quickly as possible."

About EP-NEC

Neuroendocrine carcinoma ("NEC") is a highly malignant immunologically "cold" tumor, accounting for approximately 10% to 20% of neuroendocrine neoplasms. NEC may arise in various organs, including the lung, gastrointestinal tract and bladder. NEC can be classified into pulmonary NEC and extrapulmonary NEC. EP-NEC shares the highly aggressive and metastatic characteristics of small cell lung cancer ("SCLC"), progresses rapidly, and most patients with NEC present with advanced-stage disease or distant metastases at diagnosis. Systemic treatment options for NEC are limited, with suboptimal efficacy and poor prognosis.

There are currently no therapies specifically approved by regulatory authorities worldwide for EP-NEC. First-line treatment for advanced EP-NEC primarily consists of platinum-based chemotherapy, with an objective response rate ("ORR") of approximately 30% to 50% and a median overall survival ("mOS") of only around one year. There is no standard treatment following progression on first-line therapy. Second-line treatment options may include oxaliplatin-based FOLFOX, irinotecan-based FOLFIRI, CAPTEM with or without bevacizumab, or temozolomide monotherapy. However, the efficacy of these treatment options remains limited, with an ORR of approximately 10% to 25% and an mOS of approximately eight months. Accordingly, there remains a substantial unmet medical need for patients with advanced EP-NEC, underscoring the urgent need for new and effective 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/

SOURCE Nanjing Leads Biolabs Co., Ltd.