Last reviewed 2026-04-20 · How we verify

Hympavzi (MARSTACIMAB)

Hympavzi (generic name: MARSTACIMAB) is a Monoclonal Antibody Monoclonal antibody drug developed by Pfizer Inc. It is currently FDA-approved (first approved 2025) for hemophilia A (congenital factor VIII deficiency), hemophilia B (congenital factor IX deficiency), hemophilia A (congenital factor VIII deficiency).

Hympavzi works by binding to Factor Xa, a protein involved in blood clotting.

Hympavzi (marstacimab) is a monoclonal antibody developed by Pfizer Inc, targeting Factor Xa. It is approved for the treatment of hemophilia A (congenital factor VIII deficiency) and hemophilia B (congenital factor IX deficiency). Hympavzi works by binding to Factor Xa, thereby preventing the formation of blood clots. As a patented product, it is currently only available from Pfizer Inc. Key safety considerations include the potential for hypersensitivity reactions and the need for careful monitoring of patients with bleeding disorders.

At a glance

Mechanism of action

Marstacimab‑hncq is a human monoclonal IgG1 antibody directed against the Kunitz domain 2 (K2) of TFPI to neutralize TFPI activity and enhance coagulation. TFPI is the primary inhibitor of the extrinsic coagulation cascade and negatively regulates thrombin generation within the extrinsic pathway of coagulation by inactivating the protease functions of FXa/FVIIa/TF complex. TFPI binds to and inhibits the factor Xa active site via its second Kunitz inhibitor domain (K2).

Approved indications

• hemophilia A (congenital factor VIII deficiency)
• hemophilia B (congenital factor IX deficiency)
• hemophilia A (congenital factor VIII deficiency)
• hemophilia B (congenital factor IX deficiency)

Common side effects

• Injection site reaction
• Headache
• Venous thrombosis
• Pruritus

Drug interactions

• marstacimab-hncq

Key clinical trials

• A Study to Learn About How Changing Therapy From Emicizumab to Marstacimab Affects People With the Severe Hemophilia A. (PHASE1)
• A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B (PHASE3)
• A Study to Learn About the Study Medicine -Hympavzi in Congenital Hemophilia Patients Without Inhibitors in Japan.
• Monitoring of Anti-TFPI in Hemophilia
• Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors (PHASE3)
• Adult and Adolescent Hemophilia Patients Treated With Marstacimab: a Patient Experience Registry
• Study of the Efficacy and Safety PF-06741086 in Adult and Teenage Participants With Severe Hemophilia A or Moderately Severe to Severe Hemophilia B (PHASE3)
• Study to Evaluate Safety and Tolerability of a Single Dose of PF-06741086 in Chinese Adult Participants With Severe Hemophilia (PHASE1)

Patents

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Hympavzi CI brief — competitive landscape report
• Hympavzi updates RSS · CI watch RSS
• Pfizer Inc portfolio CI

Frequently asked questions about Hympavzi

Related

• Drug class: All Monoclonal Antibody drugs
• Target: All drugs targeting Factor Xa
• Manufacturer: Pfizer Inc — full pipeline
• Therapeutic area: All drugs in Rare Disease
• Indication: Drugs for hemophilia A (congenital factor VIII deficiency)
• Indication: Drugs for hemophilia B (congenital factor IX deficiency)
• Indication: Drugs for hemophilia A (congenital factor VIII deficiency)
• Compare: Hympavzi vs similar drugs
• Pricing: Hympavzi cost, discount & access