Incyte said on June 8 it has agreed to acquire Vega Therapeutics, a wholly owned subsidiary of Star Therapeutics, for $1.25 billion in cash, pushing the hematology-focused company further into bleeding disorders. Star is eligible for up to $750 million more tied to sales milestones, for total potential consideration of up to $2.0 billion.
The prize is VGA039, an investigational monoclonal antibody. Despite the deal’s framing around von Willebrand disease (VWD), the antibody does not target von Willebrand factor directly: per Incyte, it modulates Protein S to improve hemostasis. The company describes it as a potential first subcutaneous, once-monthly prophylactic option for patients with VWD, the most common inherited bleeding disorder, who often rely on two to three intravenous infusions a week.
What the trial actually shows so far
VGA039 is in the Phase 3 VIVID-6 study (NCT07115004), which the registry lists as recruiting with a planned enrollment of 60. It is an open-label, single-sequence cross-over design — there is no concurrent control arm — pairing an observational period of at least 24 weeks with roughly 49 weeks of active treatment. The primary endpoint is the incidence of bleeding events; secondary endpoints include treated-bleed incidence, safety, drug levels and anti-drug antibodies. Primary completion is not expected until October 2028, and no Phase 3 results have been posted.
The data behind Incyte’s interest come from an earlier, much smaller study. At the December 2025 ASH annual meeting, Star presented interim Phase 1/2 multidose results: as of a November 14, 2025 cutoff, 16 patients were enrolled, with efficacy data available on the 8 who had completed dosing. The company reported annualized-bleeding-rate (ABR) reductions of 73-87% in prophylaxis-naive patients with a baseline ABR of 12 or more — the same threshold VIVID-6 requires — and 75-100% in patients switching from prior intravenous factor prophylaxis, and called the once-monthly subcutaneous regimen “safe and well tolerated.” These are interim, open-label, single-arm, company-reported figures in just 8 evaluable patients, with no control group and no confidence intervals disclosed; they are early signals, not established clinical benefit.
VGA039 fits directly into our strategy of building a top-tier growth company for the future. — Bill Meury, Incyte CEO
The FDA has granted VGA039 Breakthrough Therapy, Fast Track, orphan drug and rare pediatric disease designations. The transaction, approved by both boards, is expected to close in the third quarter of 2026 pending Hart-Scott-Rodino review. This is not investment advice.