U.S. FDA Approves Pfizer’s HYMPAVZI for the Treatment of Two Additional Hemophilia A or B Patient Populations with Significant Medical Need

June 8, 2026

Today, the U.S. Food and Drug Administration (FDA) approved an expanded indication for Pfizer’s HYMPAVZI® (marstacimab-hncq), a once-weekly subcutaneous therapy.

When HYMPAVZI was first approved in 2024, it was indicated for people with hemophilia A or B without inhibitors. Today’s FDA approval expands its use to two new groups:

• People ages 12 and older with hemophilia A or B who have inhibitors

• Children ages 6 to 11 with hemophilia A or B, with or without inhibitors

For our community, one milestone stands out: HYMPAVZI is now the first subcutaneous, non-factor therapy available to children ages 6 to 11 living with hemophilia B.

For families managing bleeding episodes from an early age, and for those living with inhibitors, expanded treatment options are always welcome. Treatment decisions are personal, and we encourage you to discuss this option, including its important safety information, with your hematologist or treatment center.

Pfizer’s full announcement follows below.