LEADS BIOLABS-B (09887) announced that on January 14, 2026, its PD-L1/4-1BB bispecific antibody, Velixin™ (Opatisumimab, LBL-024), was granted Fast Track Designation by the U.S. Food and Drug Administration (FDA) for the treatment of extra-pulmonary neuroendocrine carcinoma.

Fast Track Designation is an FDA process designed to facilitate the expedited development and review of drugs that treat serious or life-threatening conditions and address unmet medical needs.

This designation provides several important procedural incentives, including more frequent interactions and guidance from the FDA, as well as the eligibility to submit a New Drug Application on a rolling basis for regulatory approval.

Velixin™ is a bispecific antibody that simultaneously targets PD-L1 and 4-1BB, representing the world's first 4-1BB receptor-targeted therapy for extra-pulmonary neuroendocrine carcinoma to reach the registration clinical trial stage.

In Phase II or registration clinical trials for three indications—non-small cell lung cancer, small cell lung cancer, and extra-pulmonary neuroendocrine carcinoma—Velixin™ has demonstrated potential for best-in-class or first-in-class clinical activity.

Velixin™ also holds the promise of becoming the first approved drug for the treatment of advanced extra-pulmonary neuroendocrine carcinoma.

Leveraging the company's proprietary, self-developed X-body® platform, Velixin™ employs an optimal 2:2 structural design that can reverse PD-1/L1-mediated immune suppression while enhancing 4-1BB-regulated T-cell activation, achieving a synergistic tumor-killing effect and possessing broader-spectrum anti-cancer potential than PD-1/L1 inhibitors alone.

In two clinical trials conducted in China, Velixin™, whether used as a monotherapy or in combination with chemotherapy, demonstrated encouraging efficacy signals and a favorable safety profile in patients with advanced extra-pulmonary neuroendocrine carcinoma.

The company received approval from the National Medical Products Administration (NMPA) in April 2024 to initiate a single-arm registration clinical trial, obtained Breakthrough Therapy Designation (BTD) from the NMPA in October 2024 for Velixin™ in the treatment of late-line advanced extra-pulmonary neuroendocrine carcinoma, and was granted Orphan Drug Designation (ODD) from the FDA in November 2024 for the treatment of neuroendocrine carcinoma.

As an agonist, 4-1BB can reactivate exhausted T-cells and promote their massive expansion, making it particularly suitable for treating "cold tumors" that are resistant or unresponsive to PD-1/PD-L1 inhibitors.

Beyond extra-pulmonary neuroendocrine carcinoma, Velixin™ has shown encouraging clinical signals in multiple cancer types with significant unmet medical needs, including small cell lung cancer, biliary tract cancer, ovarian cancer, non-small cell lung cancer, esophageal squamous cell carcinoma, hepatocellular carcinoma, gastric cancer, triple-negative breast cancer, and melanoma, with particularly振奋ing clinical effects already observed in small cell lung cancer, biliary tract cancer, and ovarian cancer, positioning it as a promising and effective anti-tumor drug for a wide range of indications.