The U.S. Food and Drug Administration (FDA) approved Hympavzi (marstacimab-hncq) for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients aged 12 years and older with hemophilia A without factor VIII inhibitors or hemophilia B without factor IX inhibitors.

Unlike other drugs that replace a clotting factor, Hympavzi is a new type of drug that works by reducing the amount of the naturally occurring anticoagulation protein called tissue factor pathway inhibitor, thus increasing the amount of thrombin, an enzyme that is critical in blood clotting.

The approval is based on an open-label, multicenter study of 116 adult and pediatric male patients with either severe hemophilia A or severe hemophilia B, both without inhibitors. For the first six months, patients received treatment with replacement factor either on-demand (33 patients) or prophylactically (83 patients), followed by Hympavzi prophylaxis for 12 months. In the patients receiving on-demand factor replacement, the estimated annualized bleeding rate was 38 versus 3.2 with Hympavzi. In the initial six months, patients who received prophylactic factor replacement had an estimated annualized bleeding rate of 7.85, followed by 5.08 in the subsequent 12 months on Hympavzi prophylaxis.

“Today’s approval of Hympavzi provides patients with hemophilia a new treatment option that is the first of its kind to work by targeting a protein in the blood clotting process,” Ann Farrell, M.D., from the FDA Center for Drug Evaluation and Research, said in a statement. “This new type of treatment underscores the FDA’s commitment to advance the development of innovative, safe and effective therapies.”