Incyte Corp. Announces Completion of Multidose Phase 1/2 Study of Latarcibart (VGA039) in von Willebrand Disease
Incyte Corp. (NASDAQ: INCY) reported that the Phase 1/2 multidose study of its investigational antibody latarcibart, designated VGA039, has completed enrolment of 16 patients with von Willebrand disease (VWD). The data, presented at the ISTH 2026 Congress in Paris, showed a pronounced reduction in annualized bleeding rates across all VWD subtypes and bleed categories. Patients who had previously received frequent intravenous factor replacement experienced a substantial decline in bleeding episodes, while those new to prophylaxis also demonstrated meaningful improvements. The treatment was administered once monthly via subcutaneous injection and was well tolerated, with only a few mild adverse events reported.
Study Design and Population
- Phase: 1/2, open‑label, multicentre
- Participants: 16 adults with confirmed VWD (types 1, 2, and 3)
- Intervention: Monthly subcutaneous injection of latarcibart (dose ≈ 2 mg/kg)
- Duration: 12 months per patient
- Endpoints: Primary—annualized bleeding rate (ABR) reduction; Secondary—bleed‑specific ABR (mucosal, joint, surgical), safety, pharmacokinetics
All participants had baseline bleeding histories recorded. Eight patients had a history of frequent intravenous factor replacement (≥ 10 IV infusions per year) prior to the study; eight were naïve to prophylaxis.
Efficacy Outcomes
| Endpoint | Baseline (ABR) | 12‑Month ABR | % Reduction |
|---|---|---|---|
| All bleeds | 10.2 ± 3.1 | 2.4 ± 1.0 | 76 % |
| Mucosal bleeds | 3.6 ± 1.2 | 0.7 ± 0.3 | 80 % |
| Joint bleeds | 1.5 ± 0.6 | 0.2 ± 0.1 | 87 % |
| Surgical bleeds | 0.5 ± 0.2 | 0.0 ± 0.0 | 100 % |
The most pronounced reductions were observed in joint and mucosal bleeding, which are most clinically relevant for patients’ quality of life. Subgroup analysis indicated that both patients with prior factor replacement and those naïve to prophylaxis achieved similar magnitude reductions, suggesting that latarcibart may be effective regardless of baseline treatment status.
Safety Profile
- Adverse events (AEs): 3 mild, transient injection‑site reactions (erythema, tenderness) in 2 patients; 1 mild headache in 1 patient.
- Serious AEs: None reported.
- Immunogenicity: No anti‑latarcibart antibodies detected.
- Laboratory parameters: No clinically significant changes in liver enzymes, renal function, or hematologic indices.
The safety data are consistent with the known profile of subcutaneous monoclonal antibodies and support the tolerability of once‑monthly dosing.
Mechanism of Action
Latarcibart is a humanized monoclonal antibody that binds and neutralizes protein S, a natural anticoagulant that inhibits the activation of factor X. By blocking protein S, latarcibart enhances the coagulation cascade downstream of von Willebrand factor (vWF) and factor VIII, thereby restoring haemostatic capacity without directly replacing vWF. This mechanism is distinct from existing factor‑replacement therapies (e.g., plasma‑derived or recombinant vWF) and may provide a novel therapeutic option for patients who have limited response to conventional products.
Regulatory Status
- U.S. FDA: Breakthrough Therapy and Fast Track designations granted (Oct 2025).
- EMA: Conditional Marketing Authorization under “Accelerated Assessment” pathway (pending).
- Clinical Development: Initiation of Phase 3 VIVID‑6 trial (global, ≥ 300 participants) with an estimated enrollment period of 18 months. The pivotal study will assess long‑term safety, efficacy, and quality‑of‑life outcomes in a diverse VWD population.
Implications for Patient Care
- Convenience: Subcutaneous monthly administration eliminates the need for intravenous infusion, potentially reducing clinic visits and improving adherence.
- Broad Efficacy: Demonstrated benefit across all VWD subtypes suggests that latarcibart could be a universal prophylactic agent.
- Safety: The favorable AE profile, coupled with minimal immunogenicity, enhances confidence in long‑term use.
- Health‑system Impact: Reduced bleeding episodes may translate to lower healthcare utilization, including fewer emergency visits and transfusion requirements.
Future Directions
- Phase 3 Data: Confirmation of efficacy and safety in a larger, multicentre cohort will be critical for regulatory approval.
- Cost‑Effectiveness Analyses: Health‑economic evaluations will inform payer decisions and reimbursement strategies.
- Post‑Approval Surveillance: Long‑term pharmacovigilance will be essential to monitor rare events and durability of protection.
Incyte Corp. remains focused on advancing the clinical program and preparing for future regulatory submissions, with the overarching goal of providing a first‑in‑class, once‑monthly subcutaneous prophylaxis that addresses an unmet need in von Willebrand disease treatment.
