FDA approved Hympavzi (marstacimab) for Routine Prophylaxis in Hemophilia A and B Without InhibitorsFDA approved Hympavzi to prevent bleeding in hemophilia A and B.

FDA From the archive Source published October 11, 2024 Summary added June 11, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Consider Hympavzi as a subcutaneous prophylaxis option for hemophilia A or B without inhibitors, but use factor concentrates for breakthrough bleeds.

The FDA has approved Hympavzi (marstacimab) 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 factor VIII deficiency) without factor VIII inhibitors or hemophilia B (congenital factor IX deficiency) without factor IX inhibitors. Hympavzi is a tissue factor pathway inhibitor (TFPI) antagonist, offering a novel mechanism of action for these patients. The approval provides an additional subcutaneous prophylactic option for patients who may prefer an alternative to factor replacement therapy. The recommended dosing includes a loading dose of 300 mg followed by weekly maintenance doses of 150 mg, with a possible dose adjustment to 300 mg weekly for patients weighing at least 50 kg if bleeding control is inadequate.

＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)

Mechanism of Action

Hympavzi is a tissue factor pathway inhibitor (TFPI) antagonist. It binds to TFPI and inhibits its activity, thereby promoting thrombin generation and enhancing hemostasis.

Indication & Patient Population

Hympavzi is indicated 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 factor VIII deficiency) without factor VIII inhibitors, or hemophilia B (congenital factor IX deficiency) without factor IX inhibitors.

Dosing & Administration

The recommended dosage is a loading dose of 300 mg (two 150 mg subcutaneous injections) followed one week later by maintenance dosing of 150 mg every week by subcutaneous injection. Dose adjustment to 300 mg weekly can be considered in patients weighing ≥50 kg when bleeding control is inadequate. Factor VIII or IX products can be used for breakthrough bleeds; do not use additional Hympavzi doses for breakthrough bleeds. Temporarily discontinue Hympavzi before major surgery.

Key Clinical Trial Data

Trial data not available in label.

Warnings & Contraindications

Not reported in label.

Place in Therapy

Hympavzi offers a subcutaneous prophylactic option for patients with hemophilia A or B without inhibitors, potentially reducing the burden of intravenous factor replacement. It is not indicated for treatment of breakthrough bleeds, and factor concentrates should be used for such events.

The U.S. Food and Drug Administration has approved a new medicine called Hympavzi (marstacimab) for people with hemophilia. Hemophilia is a rare bleeding disorder where the blood does not clot properly. Hympavzi is for adults and children ages 12 and older who have hemophilia A or B and do not have inhibitors (antibodies that block standard treatments).

Hympavzi works in a new way. It blocks a protein called tissue factor pathway inhibitor (TFPI) that normally stops blood clotting. By blocking TFPI, the medicine helps the blood clot more easily. This can prevent or reduce how often bleeding episodes happen. The medicine is given as a shot under the skin once a week, after a first larger dose.

This approval gives patients a new option that does not require replacing the missing clotting factor. Some people may prefer this type of treatment. However, Hympavzi is not a cure. It is meant to be used regularly to prevent bleeding, not to stop bleeding that is already happening.

If you or a loved one has hemophilia, talk to your doctor about whether Hympavzi might be right for you. Your doctor can help you understand the benefits and risks based on your personal health history.

What this means for you:

Hympavzi is a new weekly shot that helps prevent bleeding in some people with hemophilia.

Study Details

Study typeFda approval

PublishedOct 2024

View Original Abstract ↓

1 INDICATIONS AND USAGE HYMPAVZI is indicated 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 factor VIII deficiency) without factor VIII inhibitors, or • hemophilia B (congenital factor IX deficiency) without factor IX inhibitors. HYMPAVZI is a tissue factor pathway inhibitor (TFPI) antagonist indicated 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 factor VIII deficiency) without factor VIII inhibitors, or • hemophilia B (congenital factor IX deficiency) without factor IX inhibitors. ( 1 )

FDA approved Hympavzi (marstacimab) for Routine Prophylaxis in Hemophilia A and B Without InhibitorsFDA approved Hympavzi to prevent bleeding in hemophilia A and B.

Study Details

Biomarkers and clinical factors show statistical associations with sepsis-induced coagulopathy in 37,459 patients

Your Blood May Signal a Deadly Clotting Crisis Before It Strikes

Clinical research that matters. Delivered to your inbox.

FDA approved Hympavzi (marstacimab) for Routine Prophylaxis in Hemophilia A and B Without InhibitorsFDA approved Hympavzi to prevent bleeding in hemophilia A and B.

Study Details

Biomarkers and clinical factors show statistical associations with sepsis-induced coagulopathy in 37,459 patients

Your Blood May Signal a Deadly Clotting Crisis Before It Strikes

Clinical research that matters. Delivered to your inbox.

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