A Pilot Crossover Trial of Prophylactic Wilate Compared to Placebo for Heavy Menstrual Bleeding in Patients with VWD

The EMPOWER trial is a pilot multi-center, placebo-controlled (normal saline), double-blind (patient and outcome assessor), crossover, 2-year randomized trial in female outpatients with von Willebrand disease (VWD) and heavy menstrual bleeding to determine trial feasibility and viability, and explore assay sensitivity of the proposed efficacy clinical outcomes for a definitive randomized controlled trial. For the first treatment period, patients will be randomized to receive either plasma derived von Willebrand factor:Factor VIII (pdVWF:FVIII) concentrate (plus standard of care) or placebo (plus standard of care) for VWD-associated heavy menstrual bleeding for 4 cycles, crossing over to the comparator treatment during the second treatment period. The first treatment period will be followed by a 1 cycle washout period when no study-based treatment will be delivered. The main purpose of the pilot will be to evaluate viability and feasibility of the trial design, as well as to explore assay sensitivity to inform determination of the primary efficacy outcome for the definitive randomized trial which will evaluate the effect of prophylaxis with pdVWF:FVIII concentrate compared with placebo on HMB in women with VWD. A secondary objective is to conduct a preliminary assessment of the effect on clinical outcomes of 2-3 doses of prophylaxis with pdVWF:FVIII concentrate when provided on the first 4 days of menstruation compared with placebo.