Plasma-derived von Willebrand factor (VWF) was safe and effective at preventing and treating hemorrhage among children with severe von Willebrand disease (VWD) aged younger than 6 years old, according to the results of a phase 3 trial published in the journal Einstein.
The safety and efficacy of VWF was previously reported for adolescent and adult patients with VWD. The aim of this trial was to further evaluate VWF among younger children for the prevention and treatment of bleeding episodes, including during surgery.
The multicenter, open-label, phase 3 trial included 9 patients with severe VWD aged younger than 6 years who were treated with VWF in response to a bleeding episode or to prevent bleeding during a surgical or invasive procedure. The primary endpoint was the ability to control bleeding episodes at last infusion and at hospital discharge for surgical/invasive procedures using a 4-point scale. Secondary endpoints included safety assessments.
Treatment with VWF was required for 62 of 92 total bleeding episodes that occurred during the study. Of the treated episodes, bleeding control was rated at excellent or good among 90.3% of cases, with the remaining 9.7% rated as moderate. There were 2 major bleeding episodes, and bleeding control was rated good in both cases.
The bleeding episodes were controlled with 1 infusion among 73% of episodes and with 2 infusions among 16%. The median dose administered per infusion was 54 IU/kg.
There were 6 patients who underwent 11 minor, preplanned procedures. Hemostasis was rated excellent for all procedures, with no blood transfusions required. The loading dose was a median of 56 IU/kg administered immediately before the procedure. There were 3 surgeries in which a dose after the procedure was required.
In the cohort, there were 2 patients with type 3 VWD who were treated with VWF as long-term prophylaxis due to a history of multiple bruises and traumatic bleeding from increased physical activity. There was 1 patient who received 624 infusions during 4 years, and demonstrated a reduction in intensity and number of bruises. The second patient began prophylactic treatment shortly before the study ended.
There were 139 treatment-emergent adverse events (AEs) reported, but none were considered treatment-related. None of the AEs resulted in treatment discontinuation. None of the patients developed VWF of FVIII inhibitors.
The authors concluded that “results from this prospective study are an addition to the limited data on VWF replacement therapy in pediatric patients.” They added that these data support that VWF “has an excellent efficacy and safety profile in children under 6 years of age with VWD.”
Disclosures: This study was funded by LFB. Please see the original reference for a full list of disclosures.
Gouider E, Klukowska A, Maes P, et al. Efficacy and safety of von Willebrand factor concentrate almost devoid of factor VIII (Wilfactin®) in paediatric patients under 6 years of age with severe von Willebrand disease. Blood Transfus. Published online April 19, 2022. doi: 10.2450/2022.0329-21