Pfizer announced that the European Commission has approved HYMPAVZI (marstacimab) for adolescents and adults with hemophilia A or B with inhibitors, supported by Phase 3 BASIS trial data showing a 93% reduction in treated annualized bleeding rate compared with on-demand therapy.
Written By: Dr. Preethi Putti, PharmD
Reviewed By: Pharmacally Editorial Team
Pfizer announced that the European Commission has granted marketing authorisation for HYMPAVZI to expand its approved indication to include patients aged 12 years and older weighing at least 35 kg with hemophilia A (congenital factor VIII deficiency) with factor VIII inhibitors or hemophilia B (congenital factor IX deficiency) with factor IX inhibitors.
HYMPAVZI targets tissue factor pathway inhibitor (TFPI), a natural anticoagulation pathway involved in regulating blood clot formation. By targeting the Kunitz 2 domain of TFPI, the therapy aims to restore the balance between bleeding and clotting through once-weekly subcutaneous administration.
The approval was supported by results from the Phase 3 BASIS study (NCT03938792), a global, open-label, multicenter trial evaluating HYMPAVZI in patients aged 12 to under 75 years with severe hemophilia A or moderately severe to severe hemophilia B, with or without inhibitors.
During the active treatment period, HYMPAVZI reduced mean treated annualized bleeding rate (ABR) by 93% compared with on-demand therapy (1.39 vs. 19.78; p<0.0001). Superiority was also demonstrated across all bleeding-related secondary endpoints, including spontaneous bleeds, joint bleeds, target joint bleeds, and total treated and untreated bleeds.
In an interim analysis of the ongoing open-label extension study, patients treated with HYMPAVZI for up to an additional 41 months, representing up to 53 months of total exposure, maintained low mean and median treated ABRs of 1.19 and 0.00, respectively.
The safety profile remained consistent with earlier Phase 1/2 findings. The most serious adverse event reported was thrombosis, while common adverse events included injection site reactions, headache, pruritus, hypertension, and rash.
Laurent Frenzel said inhibitors remain a major challenge in hemophilia because they reduce the effectiveness of traditional factor replacement therapies, leaving patients vulnerable to uncontrolled bleeding. He added that HYMPAVZI offers a once-weekly subcutaneous treatment option that has shown sustained bleed reduction in long-term follow-up studies.
Alexandre de Germay said recurrent bleeding episodes in patients with inhibitors can significantly affect daily life and joint health. He described the EU approval as an important step in expanding treatment options for patients facing complex and limited care choices, while reinforcing Pfizer’s long-standing commitment to hemophilia care.
According to Pfizer, HYMPAVZI is the first once-weekly subcutaneous treatment approved in the European Union for people living with hemophilia A or B, with or without inhibitors. The therapy has already been approved in more than 40 countries for eligible patients with hemophilia A or B without inhibitors. Pfizer also noted that HYMPAVZI was the first approved anti-TFPI therapy in both the U.S. and EU for hemophilia management and the first hemophilia treatment approved in both regions to be administered through a pre-filled auto-injector pen.
The European Commission decision applies across all 27 EU member states, as well as Iceland, Liechtenstein, and Norway. Earlier this year, the U.S. Food and Drug Administration granted Priority Review to Pfizer’s supplemental Biologics License Application seeking expanded approval of HYMPAVZI for patients aged 6 years and older with inhibitors and pediatric patients aged 6 to 11 years without inhibitors.
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About the Writer
Dr.Preethi Putti, PharmD (LinkedIn) is a pharmaceutical researcher with experience in healthcare and pharmaceutical market research and competitive intelligence. She specializes in analyzing drug pipelines, clinical data, and industry trends and translating complex scientific data into clear and structured medical content. Strong foundation in clinical research, data interpretation, and evidence-based healthcare analysis. Committed to advancing a global career in clinical research and healthcare innovation.