Leads Biolabs' PD-L1/4-1BB Bispecific Antibody Receives FDA Fast Track Designation for Rare Neuroendocrine Cancer
Key Insights
Leads Biolabs (search) announced that Opamtistomig (search) (LBL-024), its investigational PD-L1 (search)/4-1BB (search) bispecific antibody, received FDA Fast Track Designation for treating extra-pulmonary neuroendocrine carcinoma (search) (EP-NEC (search)).
This marks the third major regulatory designation for Opamtistomig (search), following Breakthrough Therapy Designation from China's NMPA and Orphan Drug Designation from the FDA.
The bispecific antibody is the first 4-1BB (search)-targeting therapy globally to advance to a single-arm pivotal trial as monotherapy and aims to become the first approved therapy specifically for EP-NEC (search).
Nanjing Leads Biolabs Co., Ltd. announced that its investigational PD-L1 (search)/4-1BB (search) bispecific antibody Opamtistomig (search) (LBL-024) has received Fast Track Designation from the U.S. Food and Drug Administration (search) for the treatment of extra-pulmonary neuroendocrine carcinoma (search) (EP-NEC (search)). This regulatory milestone represents the third major designation secured by the therapy, following Breakthrough Therapy Designation from China's National Medical Products Administration (search) in October 2024 and Orphan Drug Designation from the FDA in November 2024.
Triple Regulatory Acceleration Achievement
"With Opamtistomig (search) now receiving Fast Track Designation from the FDA—following Breakthrough Therapy Designation in China and Orphan Drug Designation in the United States—we have achieved a rare triple regulatory acceleration," stated Dr. Charles Cai, Chief Medical Officer of Leads Biolabs (search). "This milestone reflects strong regulatory confidence in the molecule's clinical potential and will meaningfully accelerate global development, shorten approval timelines, and help bring this innovative therapy to patients with high unmet needs worldwide."
The Fast Track Designation provides several procedural incentives, including more frequent regulatory communication and guidance from the FDA, as well as eligibility to submit new drug applications for regulatory approval on a rolling basis.
First-in-Class Bispecific Design
Opamtistomig (search) represents a potential first-in-class bispecific antibody that simultaneously targets PD-L1 (search) and the co-stimulatory receptor 4-1BB (search). The therapy is the first 4-1BB-targeting bispecific antibody globally to advance to a single-arm pivotal trial as monotherapy and aims to become the first approved therapy specifically for EP-NEC (search)—a rare malignancy with substantial unmet clinical need.
Developed using Leads Biolabs (search)' proprietary X-Body bispecific platform, Opamtistomig (search) features a 2:2 molecular format, incorporating two binding domains each for PD-L1 (search) and 4-1BB (search) 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.
Clinical Progress and Mechanism
In two ongoing clinical studies in China, Opamtistomig (search) has demonstrated promising efficacy and a favorable safety profile in patients with advanced EP-NEC (search), 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.
Mechanistically, 4-1BB (search) agonism can reactivate exhausted T cells and promote robust T-cell proliferation, offering significant development for PD-1 (search)/PD-L1 (search)-resistant or immunologically "cold" tumors. To date, Opamtistomig (search) has demonstrated first- or best-in-class potential in Phase II or registrational clinical trials across three indications: non-small cell lung cancer (search) (NSCLC (search)), small cell lung cancer (search) (SCLC (search)), and EP-NEC (search).
Broad Clinical Development Program
Beyond EP-NEC (search), Opamtistomig (search) has received clinical trial approvals across multiple tumor types with high unmet medical needs, including small cell lung cancer (search), biliary tract cancer (search), ovarian cancer (search), non-small cell lung cancer (search), esophageal squamous cell carcinoma (search), hepatocellular carcinoma (search), gastric cancer (search), triple-negative breast cancer (search), and malignant melanoma (search). Encouraging clinical activity has already been observed in NSCLC (search), SCLC (search), biliary tract cancer, ovarian cancer, and other indications, underscoring Opamtistomig's potential as a broad-spectrum immuno-oncology therapy.
Founded in 2012, Leads Biolabs (search) is a clinical-stage biotechnology company with a differentiated pipeline of 14 innovative drug candidates, including seven clinical-stage drug candidates. The company has developed multiple proprietary technology platforms, including the LeadsBody platform (a CD3 (search) T-cell engager platform), X-body platform (a 4-1BB (search) engager platform), and TOPiKinectics (ADC platform).