Star Therapeutics recently announced interim data from an ongoing phase 1/2 clinical trial evaluating its investigational von Willebrand disease (VWD) therapy VGA039.
VGA039 is a subcutaneous (sub-Q) monoclonal antibody therapy designed to target the clot regulating protein known as Protein S to regulate excessive clotting and coagulation in people with all subtypes of VWD. Sub-Q therapies require an injection just under the skin, as opposed to intravenously administered products which necessitate venous access. As an easier to administer therapy, sub-Q treatments have the advantage of greater convenience which in turn may increase rates of adherence.
The interim data was based on 16 patients currently participating in the phase 1/2 trial. It includes safety data on all 16 patients and efficacy data on the eight patients who had completed treatment with VGA039, which encompasses once per monthly prophylactic doses of the therapy. According to a company press release, the therapy was safe, well tolerated, and showed a major reduction (73%-87%) in annual bleeding rate (ABR) across various VWD types. For patients who switched to VGA039 from a prophylactic regimen that included intravenous doses of von Willebrand factor products multi times per week, ABR decreased 75%-100%. The data was presented at the 67th American Society of Hematology Annual Meeting and Exposition, held December 6-9 in Orlando, FL.
“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. VGA039’s ability to consistently reduce bleeding across these groups along with its favorable safety and tolerability profile indicate that VGA039 has the potential to improve outcomes for all patients with VWD,” said Steven Pipe, MD, 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,” added Pipe.
Patient recruitment for a phase 3 trial of VGA039 is underway. The U.S. Food and Drug Administration had granted fast track designation for Star Therapeutics’ VGA039 at the beginning of this year.
Source: Star Therapeutics press release dated December 6, 2025
