Pfizer has announced encouraging topline results from its Phase 3 BASIS trial evaluating HYMPAVZI (marstacimab) in patients with hemophilia A or B who have developed inhibitors. The study demonstrated a significant reduction in annualized bleeding rates (ABR) among participants treated with HYMPAVZI compared to those receiving on-demand treatment.
In the 12-month study period, HYMPAVZI reduced ABR by 93% (1.39 vs. 19.78) in patients with severe hemophilia A or B with inhibitors. The treatment also showed superiority across multiple bleeding-related secondary endpoints, including spontaneous bleeds, joint bleeds, target joint bleeds, and total bleeds.
HYMPAVZI is a once-weekly subcutaneous therapy that targets the tissue factor pathway inhibitor (TFPI), offering a novel mechanism of action for patients with inhibitors who have limited treatment options. The therapy has already received FDA approval for use in patients without inhibitors and is administered via a pre-filled auto-injector pen, simplifying the treatment process.
These results highlight HYMPAVZI’s potential to address unmet needs in the hemophilia community, particularly for those with inhibitors who face challenges with existing prophylactic treatments.
