Star Therapeutics Raises $125M to Advance Bleeding Disorder Drug

Star Therapeutics has announced the closing of an oversubscribed $125 million Series D financing round to accelerate the development of its pipeline of antibody-based therapies, particularly its lead program, VGA039, a potential treatment for bleeding disorders.

The round was co-led by Sanofi Ventures and Viking Global Investors, with participation from new and existing backers including Janus Henderson Investors, Frazier Life Sciences, GordonMD Global Investments, and others. The funding will primarily support Star’s ongoing clinical programs, including a pivotal Phase 3 trial of VGA039 in patients with von Willebrand disease (VWD), the most common inherited bleeding disorder.

VGA039 is a first-in-class monoclonal antibody targeting Protein S to help restore clotting balance. Administered as a once-monthly subcutaneous injection, it is designed to reduce the treatment burden compared to standard therapies like factor replacement prophylaxis, which often requires multiple IV infusions per week.

“We’re making significant progress across our pipeline, highlighted by the recent initiation of our Phase 3 trial of VGA039 to prevent bleeding in people with all types of VWD,” said Star CEO and founder Adam Rosenthal, Ph.D. “This new funding from leading life sciences investors reinforces the urgency and impact of our mission: to bring life-changing therapies to people living with serious bleeding disorders.”

In connection with the financing, Jason Hafler, Ph.D., of Sanofi Ventures will join Star’s board of directors, while Maneka Mirchandaney of Viking Global Investors will serve as a board observer.

Star’s approach in targeting VWD has attracted investor attention due to the size of the patient population—over 50,000 diagnosed and treated in the U.S.—and the unmet need for more convenient and effective therapies. The company is positioning VGA039 as a universal hemostatic therapy with the potential to reshape standard care not only in VWD, but across a range of bleeding conditions.