Incyte reported Phase 1/2 data showing latarcibart reduced annualized bleeding by 81% in von Willebrand disease and supported ongoing Phase 3 VIVID-6 development.
Written By: Farha Farheen, PharmD
Reviewed By: Pharmacally Editorial Team
Incyte has reported complete Phase 1/2 multidose results showing that latarcibart (VGA039), an investigational Protein S-targeting monoclonal antibody, reduced the median annualized bleeding rate (ABR) by 81% in patients with von Willebrand disease (VWD). The once-monthly subcutaneous therapy also demonstrated a favorable safety profile across all enrolled patients, supporting its ongoing pivotal Phase 3 VIVID-6 trial.
The data, presented during an oral session at the 34th Congress of the International Society on Thrombosis and Haemostasis (ISTH 2026) in Paris, included all 16 participants who completed six doses of latarcibart. The findings strengthen evidence that the therapy could become the first targeted prophylactic treatment for all major types of VWD.
Latarcibart Targets Protein S to Improve Hemostasis
Von Willebrand disease is the most common inherited bleeding disorder and results from deficient or dysfunctional von Willebrand factor (VWF), a protein essential for normal blood clotting. Many patients experience recurrent bleeding episodes requiring frequent intravenous infusions of VWF replacement products.
Latarcibart offers a different therapeutic approach by targeting Protein S, a natural anticoagulant. By modulating Protein S activity, the monoclonal antibody enhances platelet attachment and fibrin formation, improving hemostasis without replacing VWF. Its once-monthly subcutaneous administration may also reduce treatment burden compared with current prophylactic therapies that often require multiple intravenous infusions each week.
Phase 1/2 Study Demonstrated Consistent Bleeding Reduction
The multidose study (NCT05776069) evaluated six monthly doses of latarcibart in 16 patients with various forms of VWD. As of the May 5, 2026 data cutoff, every participant had completed treatment.
The study showed clinically meaningful reductions in bleeding across all disease types and bleeding categories, including gastrointestinal bleeding and hemophilia-like joint and muscle bleeds.
Key efficacy findings included
- Median annualized bleeding rate reduction of 81% across all VWD types and bleeding categories.
- Patients switching from prior VWF-containing intravenous prophylaxis achieved 75% to 100% reductions in bleeding episodes.
- Among seven patients with historical ABRs greater than 12 who were not receiving previous IV prophylaxis, bleeding reductions ranged from 46% to 100%, with six patients achieving reductions exceeding 73%.
- Treatment reduced VWF-treated breakthrough bleeds by approximately 86%, while 70% of patients with previous breakthrough bleeds experienced none during treatment.
- All participants with substantial bleeding burden entered the ongoing open-label extension study to continue receiving latarcibart.
Safety Profile Supports Continued Development
Latarcibart was generally safe and well tolerated throughout the multidose study.
Only three treatment-related adverse events were reported, consisting of two Grade 2 headaches in one patient and one Grade 1 injection-site reaction. Investigators also reported one serious gastrointestinal bleeding event, which was considered unrelated to treatment in a patient with a history of severe recurrent GI bleeding.
The favorable safety findings support continued evaluation of long-term prophylactic therapy with monthly dosing.
Phase 3 VIVID-6 Trial Continues Global Enrollment
According to Incyte, the multidose results reinforce the clinical rationale for the ongoing Phase 3 VIVID-6 trial (NCT07115004), which is evaluating once-monthly subcutaneous latarcibart prophylaxis in patients with all major types of VWD who have a high bleeding burden.
Company leadership said the results demonstrate consistent bleeding protection across a diverse patient population, including those transitioning from intensive intravenous prophylaxis. Investigators also noted that the combination of substantial bleed reduction and convenient monthly dosing could lessen treatment burden while providing durable protection against recurrent bleeding.
Latarcibart has received Breakthrough Therapy, Fast Track, Orphan Drug, and Rare Pediatric Disease designations from the U.S. Food and Drug Administration. Incyte added the program to its pipeline through the July 2026 acquisition of Vega Therapeutics.
If the Phase 3 study confirms these findings, latarcibart could become the first targeted, once-monthly prophylactic therapy approved for patients with von Willebrand disease.
What This Means for Patients
Current preventive treatment for severe von Willebrand disease often requires frequent intravenous infusions, creating a substantial treatment burden. Latarcibart has shown the potential to reduce bleeding episodes with a single monthly subcutaneous injection while maintaining a favorable safety profile. If successful in Phase 3 and approved, it could offer patients a more convenient long-term option for preventing recurrent bleeding.
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About the Writer
Farha Farheen, PharmD (LinkedIn) is a pharmacy professional with a strong interest in pharmacovigilance and clinical research. She has completed her Doctor of Pharmacy (Pharm.D) along with her internship as a Clinical Pharmacist. She has hands-on experience in adverse drug reaction (ADR) reporting, safety data documentation, and pharmacovigilance workflows, and is proficient in using VigiFlow. She is also a patent holder for an antibacterial formulation enriched with bioactive substances, granted by the German Patent and Trademark Office.