Pfizer Inc Approves Hympavzi for Treatment of Adults and Adolescents with Hemophilia A or B with Inhibitors

Pfizer Inc. announced that the European Commission (EC) 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. This indication extension is based on results from the Phase 3 BASIS trial (NCT03938792) 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) (1.39 [95% CI: 0.85-2.29] vs.

19.78 [95% CI: 16.12-24.27]; pAbout HYMPAVZI. Discovered by Pfizer scientists, HYMPAVZI has a unique mechanism of action that is differentiated from FVIII and FIX replacement treatments. Instead of replacing missing or insufficient clotting factors, HYMPAVZI is intentionally designed to target tissue factor pathway inhibitor (TFPI), one of the body?s natural mechanisms that inhibits the initiation of blood clotting.

By targeting the Kunitz 2 domain of TFPI, HYMPAVZI may help re-establish balance between bleeding and blood clot formation with the goal of offering a combination of bleed protection and straightforward administration. HYMPAVZI is a hemophilia treatment that has received regulatory approvals in more than 40 countries for eligible patients living with hemophilia A without factor VIII inhibitors, or hemophilia B without factor IX inhibitors. HYMPAVZI was the first anti-TFPI approved in the U.S. and EU for the treatment of hemophilia A or B and the first hemophilia medicine approved in the U.S. and EU to be administered via a pre-filled auto-injector pen.

For eligible people living with hemophilia B, it is the first once-weekly subcutaneous prophylactic treatment. HYMPAVZI is a subcutaneous treatment option with a once-weekly dosing schedule and minimal preparation required for each individual administration. Pfizer is also conducting BASIS KIDS, an open-label study investigating the safety and efficacy of HYMPAVZI in children About the BASIS Clinical Trial.

The pivotal BASIS study is a global, Phase 3, open-label, multicenter study to evaluate the efficacy data and safety profile of HYMPAVZI in adolescent and adult participants ages 12 to About Hemophilia. Hemophilia is a family of rare genetic blood diseases caused by a clotting factor deficiency (FVIII in hemophilia A, FIX in hemophilia B), which prevents normal blood clotting. Hemophilia is diagnosed in early childhood and impacts more than 800,000 people worldwide.

The inability of the blood to clot properly can increase the risk of painful bleeding, including inside the joints, which can cause joint scarring and damage. People living with hemophilia can suffer permanent joint damage following repeated bleeding episodes. For decades, the most common treatment approach for hemophilia A and B has been factor replacement therapy, which replaces the missing clotting factors.

Factor replacement therapies increase the amount of clotting factor in the body to levels that improve clotting, resulting in less bleeding. The burden of intravenous infusions is believed to be a barrier to treatment adherence for some people living with hemophilia due in part to inconvenience, time constraints, and poor venous access. Approximately 20% of people with hemophilia A and 3% of people with hemophilia B are unable to continue taking factor replacement therapies because they develop inhibitors to FVIII and FIX, respectively.

These patients often have higher treatment burden, including potential complications from bleeding such as hospitalization and death, as well as higher treatment-related costs.