European Commission approves Hympavzi (marstacimab) for the treatment of adults and adolescents with Hemophilia A or B with inhibitors – Pfizer

Pfizer announced that the European Commission has granted marketing authorization to expand the approved indication for Hympavzi (marstacimab) to include patients 12 years of age and older weighing at least 35 kg with hemophilia A (congenital factor VIII [FVIII] deficiency) with FVIII inhibitors or hemophilia B (congenital factor IX [FIX] deficiency) with FIX inhibitors.

HYMPAVZI offers a combination of superior bleed protection compared to on-demand (OD) treatment that is well-tolerated with a straightforward, once-weekly subcutaneous injection administration that does not require routine treatment-related lab monitoring for this difficult-to-treat inhibitor patient population 12 years of age and older.

Inhibitors limit treatment options for people living with hemophilia and are associated with an increased risk of uncontrolled bleeding. These inhibitory antibodies neutralize factor replacement therapies and render them ineffective. Of the more than 800,000 people in the world living with hemophilia A or hemophilia B, approximately 20% of those with hemophilia A and 3% of those with hemophilia B are unable to continue taking factor replacement therapies because they developed inhibitors to FVIII and FIX, respectively, and these therapies no longer prevent or stop bleeding episodes, particularly in individuals who are refractory to immune tolerance induction therapy.

Dr. Laurent Frenzel, Head of the Hemophilia Treatment and Research Center at the Necker-Enfants malades Hospital (Paris Cité) “Inhibitors present a substantial challenge for people living with hemophilia as they neutralize traditional factor replacement therapies, in turn limiting treatment options and leaving patients vulnerable to uncontrolled bleeding episode. The approval of Hympavzi offers adults and adolescents in the EU a once-weekly subcutaneous option that has demonstrated the ability to reduce bleeding episodes and maintain bleed reduction based on observation to date in a long-term extension study.”

This indication extension is based on results from the Phase 3 BASIS trial that evaluated the efficacy and safety of Hympavzi in adults and adolescents 12 years and older with severe hemophilia A or moderately severe to severe hemophilia B with inhibitors:

In the active treatment period of the study, Hympavzi treatment resulted in a statistically significant and clinically meaningful 93% reduction in the mean treated annualized bleeding rate (ABR) demonstrating superiority over OD therapy.

The safety profile for Hympavzi was consistent with Phase 1/2 results, and the most frequently reported adverse events in the study were injection site reactions, headache, pruritus, hypertension, and rash. The most serious adverse event reported from the clinical studies with Hympavzi was thrombosis.

This marketing authorization is valid in all 27 EU member states, as well as in Iceland, Liechtenstein, and Norway. Separately, the U.S. Food and Drug Administration (FDA) accepted and granted Priority Review for the supplemental Biologics License Application (sBLA) for HYMPAVZI to expand its approved indication to include the treatment of hemophilia A or B patients 6 years and older with inhibitors, and pediatric patients (ages 6 to 11) with hemophilia A or B without inhibitors earlier this year. In the U.S., HYMPAVZI is currently approved for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients 12 years of age and older with hemophilia A (congenital FVIII deficiency) without factor VIII inhibitors or hemophilia B (congenital FIX deficiency) without factor IX inhibitors. The FDA has set a Prescription Drug User Fee Act (PDUFA) action date in the second quarter of 2026.