Nanjing, China - January 22, 2026 - Nanjing Leads Biolabs Co., Ltd. (“Leads Biolabs” or the “Company,” Stock Code: 9887.HK) today announced that Opamtistomig (LBL-024), its core investigational PD-L1/4-1BB bispecific antibody, has been granted Orphan Drug Designation (ODD) by the European Commission (EC) for the treatment of extra-pulmonary neuroendocrine carcinoma (EP-NEC). This marks another important milestone in the global development of this innovative therapy. 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 EP-NEC.

According to the EC definition, orphan drugs are intended for the diagnosis, prevention, or treatment of life-threatening or chronically debilitating conditions affecting not more than five in ten thousand persons in the European Union. The designation provides important development and commercialization incentives, including:

• Protocol assistance, under which the European Medicines Agency (EMA) offers scientific advice on study design and development strategies across quality, safety, and efficacy considerations.
• Ten years of market exclusivity in the European Union following marketing authorization, during which similar products for the same indication generally may not be approved, independent of patent protection.
• Reductions or exemptions from regulatory fees, including those related to protocol assistance, marketing authorization applications, inspections, post-authorization variations, and annual fees.
• Potential access to funding from European Union programs, including Horizon Europe and other public funding mechanisms; and
• Additional incentives for micro, small, and medium-sized enterprises (SMEs), including regulatory, administrative, and procedural support.

Executive Commentary

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, commented:

"The grant of ODD by EC marks further recognition of our technology platform and clinical data by international regulators. This designation will provide policy support for the development, registration, and commercialization of Opamtistomig in the EU, accelerating its global development process and bringing this innovative therapy to patients worldwide sooner."

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 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/

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