Efficacy of a 1:1 ratio VWF/FVIII concentrate in patients with von Willebrand disease.

ABSTRACT

INTRODUCTION: Patients with von Willebrand disease (VWD) require administration of von Willebrand factor (VWF) concentrates peri-operatively. Concerns about FVIII accumulation after repetitive injections of a 11 ratio VWF/FVIII clotting factor concentrate (CFC) led this study to explore the recovery and FVIII accumulation over time. METHODS: This monocentre study examined patients with VWD receiving perioperative 11 ratio CFC infusions. CFC dosing was based on body weight and endogenous VWF/FVIII activity. FVIII and VWF activity was monitored at T0 (baseline), T1 (15 min postinfusion), and trough levels at T2-T6 (24-120 h). RESULTS: We included 125 patients, undergoing 125 procedures (63 major surgeries, 62 minor), with a median of two CFC infusions (IQR 1-3). With a mean administered dose of 35.7 IU/kg CFC, recovery rates of FVIII and VWF were 2.6 IU/dL per IU/kg and 2.4 IU/dL per IU/kg, respectively. Mean FVIII levels at T0 were 62 (SD 51.9), T1 164 (SD 80.4), T2 155 (SD 62.8), T3 162 (SD 59.8), T4 124 (SD 78.4), and T5 120 (SD 65.3) IU/dL. Mean VWF activity levels at T0 were 29 (SD 25.0), T1 133 (SD 43.7), T2 92 (SD 37.2), and T3 86 (SD 37.5) IU/dL. Subgroup analysis in 47 patients with more than three infusions, showed no accumulation of mean FVIII levels. CONCLUSION: This perioperative study demonstrated excellent FVIII and VWF recovery of a 11 ratio VWF product in patients with VWD. Stable FVIII and VWF activity levels were observed after repeated infusions, without accumulation. Most major surgeries required only three CFC infusions.