Nanjing Leads Biolabs Co., Ltd. (“Leads Biolabs” or the “Company,” Stock Code: 9887.HK) announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to its core product opamtistomig (LBL-024), a PD-L1/4-1BB bispecific antibody, for the first-line treatment of advanced or metastatic biliary tract cancer (BTC).

This is the second FDA Fast Track Designation for opamtistomig, following its previous designation in extrapulmonary neuroendocrine carcinoma (EP-NEC). The BTC designation was granted just nine days after submission, reflecting the urgency of addressing unmet medical needs in this patient population and the potential clinical value of the program. The FDA has also recommended that the Company promptly initiate discussions regarding the U.S. registration plans for opamtistomig in combination with chemotherapy for BTC. These developments provide important regulatory momentum for the program and may help streamline its development and registration pathway in the United States.

FDA Fast Track Designation: Supporting Development in an Area of High Unmet Medical Need

Fast Track Designation is an FDA program designed to facilitate the development and expedite the review of drugs and biologics intended to treat serious or life-threatening conditions and to address unmet medical needs. The designation provides opportunities for more frequent communication with the FDA and guidance on key development considerations, including clinical trial design and data requirements. If applicable regulatory criteria are met, Fast Track-designated products may also qualify for rolling review of their marketing applications, allowing completed sections to be submitted for review before the entire application is finalized. These mechanisms can facilitate development planning and potentially expedite the regulatory review process. For opamtistomig, the designation represents an important step in advancing a differentiated immunotherapy approach for first-line advanced BTC, a disease characterized by poor prognosis and limited effective treatment options.

Opamtistomig: A Differentiated Approach to Immunologically Cold Tumors

Opamtistomig is a PD-L1/4-1BB bispecific antibody designed to conditionally activate 4-1BB-mediated T-cell stimulation in the tumor microenvironment. By combining PD-L1 blockade with localized immune costimulation, opamtistomig is designed to relieve tumor-associated immune suppression while enhancing antitumor T-cell activity. This differentiated mechanism may offer particular potential in immunologically cold tumors, where existing immunotherapies often provide limited benefit.

In the Company’s Phase I/IIa basket study of opamtistomig monotherapy, initiated in 2022, 175 patients with advanced solid tumors were enrolled. Preliminary clinical findings across several difficult-to-treat tumor types—including BTC, platinum-resistant ovarian cancer, PD-1-refractory advanced hepatocellular carcinoma (HCC), and previously treated EP-NEC—have shown encouraging signals of potential survival benefit. These findings that are expected to be published in an international journal support further investigation of opamtistomig as a potential treatment option for patients with high unmet medical needs.

First-Line BTC Program Advances Toward Further Clinical Development

Leads Biolabs’ first-line advanced BTC program has continued to progress. In April 2026, following encouraging safety and efficacy findings, the Phase II study of opamtistomig in combination with chemotherapy advanced into the expansion phase. The Company subsequently completed enrollment across the study, marking an important milestone in evaluating this combination regimen.

The FDA’s Fast Track Designation, together with the agency’s recommendation to initiate discussions on the U.S. registration strategy, provides further impetus for the program’s continued development. The Company plans to engage proactively with the FDA to align on the clinical evidence and development strategy needed to support potential registration.

Executive Commentary

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

“The FDA’s decision to grant Fast Track Designation just nine days after submission is an encouraging milestone for opamtistomig and our first-line BTC program. We appreciate the FDA’s engagement and its recommendation to initiate discussions on the U.S. registration strategy for opamtistomig in combination with chemotherapy.

BTC represents a significant unmet medical need, and immunologically cold tumors remain a major challenge for cancer immunotherapy. Opamtistomig’s differentiated PD-L1/4-1BB mechanism is designed to address this challenge by combining immune checkpoint blockade with conditional T-cell costimulation. Across multiple difficult-to-treat tumor types, we have observed encouraging clinical signals that support further exploration of its potential. We will continue to advance our clinical programs with scientific rigor and executional focus, working closely with regulatory authorities to accelerate development and bring potentially meaningful new treatment options to patients worldwide.”