Star Therapeutics Reports Promising Phase 1/2 Data for VGA039 in Von Willebrand Disease, Showing 73-100% Reduction in Bleeding Episodes
核心洞察
Star Therapeutics (搜索) presented interim Phase 1/2 data for VGA039, a first-in-class monoclonal antibody targeting Protein S, demonstrating substantial bleeding reductions across all von Willebrand disease (搜索) types at the ASH Annual Meeting.
The once-monthly subcutaneous therapy achieved 73-87% bleeding reduction in treatment-naive patients and 75-100% reduction in patients switching from current IV prophylaxis treatments.
VGA039 showed favorable safety and tolerability across 16 enrolled patients, with all 8 patients completing treatment transitioning to an open-label extension study.
Star Therapeutics (搜索) announced compelling interim results from its Phase 1/2 multidose study of VGA039 in von Willebrand disease (搜索) (VWD), demonstrating substantial reductions in bleeding episodes across all disease types. The data, presented at the 67th American Society of Hematology (ASH) Annual Meeting in Orlando, Florida, showed that the once-monthly subcutaneous therapy achieved bleeding reductions of 73-87% in treatment-naive patients and 75-100% in patients switching from current intravenous prophylaxis.
Novel Mechanism Targets Protein S for Hemostasis
VGA039 represents a first-in-class monoclonal antibody therapy with a novel mechanism of action that targets Protein S. The drug works through dual actions, promoting platelet attachment and enhancing fibrin deposition to restore hemostasis. This approach differs from current von Willebrand factor (VWF)-containing therapies that require multiple intravenous infusions per week.
"The data presented at ASH indicate that VGA039 could be transformative for people living with VWD, a condition with more than 130,000 diagnosed patients in the U.S. alone," said Allison Wheeler, M.D., MSCI, Associate Professor of Pediatrics at the University of Washington. "VWD can have a significant impact on quality of life, with patients experiencing frequent and severe bleeds that can require hospitalization."
Comprehensive Efficacy Across Patient Populations
The Phase 1/2 multidose study enrolled 16 patients with Types 1, 2, and 3 VWD who have high disease burden, including patients with serious gastrointestinal and hemophilia-like joint and muscle bleeds. As of November 14, 2025, interim data were available for all enrolled patients, with safety data on all 16 participants and efficacy data on the 8 patients who completed treatment.
The study demonstrated substantial reductions in annual bleeding rate (ABR) across all types of VWD and all types of bleeds. For participants with ABR ≥ 12 and no prior IV prophylaxis—matching the population being recruited for the Phase 3 trial—bleeding reductions ranged from 73-87%. Notably, patients switching from prior VWF-containing prophylaxis experienced even greater improvements, with bleeding reductions of 75-100%.
"This dataset is compelling, encompassing a diverse patient population across multiple VWD types, a full spectrum of bleed profiles, and individuals transitioning from prior prophylaxis regimens," said Steven Pipe, M.D., Professor of Pediatrics and Pathology at the University of Michigan. "Importantly, patients who transitioned from IV prophylaxis multiple times per week to once monthly subcutaneous VGA039 experienced marked improvements in bleed control, highlighting the potential to establish a new standard of care for people living with VWD."
Safety Profile and Patient Retention
VGA039 demonstrated a favorable safety and tolerability profile throughout the study. All participants who completed the multidose study opted to continue treatment in the open-label extension study, indicating strong patient acceptance of the therapy.
"These interim data provide further validation of VGA039 as a potential once monthly subcutaneous treatment for multiple bleeding disorders (搜索), starting with VWD," said Gary Patou, M.D., Chief Medical Officer of Star Therapeutics (搜索). "All patients to date have opted to continue treatment as part of our open-label extension study after finishing the multidose trial."
Advancing to Phase 3 Development
The company has initiated its pivotal Phase 3 study, VIVID-6 (NCT07115004), a global single-arm crossover study designed to investigate the safety and efficacy of subcutaneous VGA039 as prophylaxis for bleeding in patients with every type of VWD. VGA039 has received Fast Track and orphan drug designations from the U.S. Food and Drug Administration.
Von Willebrand disease (搜索) is the most common inherited bleeding disorder, caused by absent or defective von Willebrand factor. Current therapies for VWD prophylaxis include factor replacement therapies requiring multiple intravenous infusions every week, creating a significant treatment burden for patients.
The potential for VGA039 to serve as a universal hemostatic therapy extends beyond VWD, with the company positioning it to treat numerous bleeding disorders (搜索). As a subcutaneously self-administered antibody therapy with once-monthly dosing, VGA039 could dramatically reduce treatment burden while potentially providing superior bleed control compared to current standard-of-care options.