Marstacimab

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.

• 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.

• None. None.contraindicated

• See Full Prescribing Information for important dosing and administration instructions. ( 2.1 , 2.2 , 2.3 , 2.4 , 2.5 , 2.6 ) • The recommended dosage of HYMPAVZI is: o Loading dose: 300 mg (two 150 mg injections) by subcutaneous injection o Maintenance dose: One week after the loading dose, initiate maintenance dosing of 150 mg every week by subcutaneous injection on the same day each week, at any time of day. ( 2.1 ) • Dose adjustment to 300 mg subcutaneous injection weekly can be considered. ( 2.1 ) • Factor VIII and factor IX products can be administered for the treatment of breakthrough bleeds in patients receiving HYMPAVZI. Do not use additional doses of HYMPAVZI to treat breakthrough bleeds. ( 2.4 ) • Temporarily discontinue HYMPAVZI before major surgery. ( 2.5 ) 2.1 Recommended Dosage For subcutaneous use only. The recommended dosage of HYMPAVZI for adult and pediatric patients 12 years of age and older is as follows: Loading Dose 300 mg (two 150 mg subcutaneous injections) If more than one injection is required to deliver a complete dose, administer each injection at a different injection site. Maintenance Dose One week after the loading dose, initiate maintenance dosing of 150 mg every week by subcutaneous injection on the same day each week, at any time of day. Dose Adjustment During Treatment Consider a dose adjustment to 300 mg subcutaneous injection weekly in patients weighing greater than or equal to 50 kg when control of bleeding events is judged to be inadequate by the healthcare provider.

• Thromboembolic Events: Thromboembolic events may occur. Interrupt HYMPAVZI prophylaxis if symptoms occur. ( 5.1 ) • Hypersensitivity: Hypersensitivity reactions may occur. In the event of a severe allergic reaction, discontinue HYMPAVZI. ( 5.2 ) • Embryofetal Toxicity: May cause fetal harm. Advise females of reproductive potential of the potential risk to the fetus and to use effective contraception. ( 5.3 , 8.1 , 8.3 ) 5.1 Thromboembolic Events HYMPAVZI is a tissue factor pathway inhibitor (TFPI) antagonist, and may increase the risk of thromboembolic complications. Venous thrombotic events were reported in clinical studies with HYMPAVZI [see Adverse Reactions (6.1) ] . Patients with independent risk factors for thromboembolic events may be at increased risk of thromboembolic events with use of HYMPAVZI. HYMPAVZI has not been studied in patients with a history of previous thromboembolic events [see Clinical Studies (14.1) ] . Consider the benefit and risk of using HYMPAVZI in patients with known risk factors for thromboembolism. Interrupt HYMPAVZI prophylaxis if diagnostic findings consistent with thromboembolism occur and manage as clinically indicated. If factor VIII or factor IX products are indicated in a patient receiving HYMPAVZI prophylaxis, the minimum effective dose of factor VIII or factor IX according to the product label is recommended [see Dosage and Administration (2.4) ] . 5.2 Hypersensitivity HYMPAVZI may cause hypersensitivity reactions (including, but not limited to urticaria and pruritus).

The following clinically significant adverse reactions are described elsewhere in the labeling: • Thromboembolic Events [see Warnings and Precautions (5.1) ] • Hypersensitivity [see Warnings and Precautions (5.2) ] Adverse reactions reported in ≥3% of HYMPAVZI-treated patients were injection site reaction, headache, and pruritus. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc. at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of HYMPAVZI was evaluated in adolescent and adult patients with severe hemophilia A or B without inhibitors (coagulation factor activity <1%) enrolled in the BASIS study [see Clinical Studies (14.1) ] . Patients (N = 116) received HYMPAVZI prophylaxis 300 mg loading dose followed by 150 mg every week starting at Day 8 administered subcutaneously. Among patients receiving HYMPAVZI, 97% were exposed for 6 months or longer and 75% were exposed for at least 1 year. A serious adverse reaction of peripheral swelling occurred in one patient. Table 1 summarizes the adverse reactions reported in ≥3% of patients who received HYMPAVZI prophylaxis. Table 1.

8.1 Pregnancy Risk Summary Based on its mechanism of action, HYMPAVZI may cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1) ] . There are no available data on HYMPAVZI use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. Female animal reproduction studies have not been conducted with HYMPAVZI. Although there are no data on marstacimab‑hncq, monoclonal antibodies can be actively transported across the placenta, and marstacimab‑hncq may cause fetal harm. The background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. 8.2 Lactation Risk Summary There are no data on the presence of marstacimab‑hncq in either human or animal milk, the effects on the breastfed child, or the effects on milk production. Endogenous maternal IgG and monoclonal antibodies are known to be present in human milk. The effects of local gastrointestinal exposure and limited systemic exposure in the breastfed child to marstacimab‑hncq are unknown.

Metabolism

Estimated mean marstacimab‑hncq C min,ss , C max,ss , and C avg,ss for adults and adolescents weighing at least 35 kg following marstacimab‑hncq 150 mg subcutaneous once-weekly administration are shown in Table 2. Marstacimab‑hncq area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C max ) increase in a greater than dose-proportional manner over the dose range of 100 mg to 450 mg (0.67 to 3 times the approved recommended dosage).

• Oct 11, 2024BLABLA761369Pfizer Inc

1. 1Haemarthrosis1020%
2. 2Device Failure47.8%
3. 3Haemorrhage47.8%
4. 4Arthralgia35.9%
5. 5Contusion35.9%
6. 6Device Defective35.9%
7. 7Drug Dose Omission By Device35.9%
8. 8Epistaxis35.9%
9. 9Alanine Aminotransferase Increased23.9%
10. 10Aspartate Aminotransferase Increased23.9%
11. 11Brain Fog23.9%
12. 12Device Delivery System Issue23.9%
13. 13Drug Ineffective23.9%
14. 14Fall23.9%
15. 15Fracture23.9%

The 10 most recently updated of 12 ClinicalTrials.gov registrations naming Marstacimab as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• A Study to Learn About How Changing Therapy From Emicizumab to Marstacimab Affects People With the Severe Hemophilia A.
  Recruiting · Phase 1 · Interventional · 15 enrolled · Pfizer
  NCT06703606updated 2026-06-03
• A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
  Recruiting · Phase 3 · Interventional · 100 enrolled · Pfizer
  NCT05611801updated 2026-05-07
• Adult and Adolescent Hemophilia Patients Treated With Marstacimab: a Patient Experience Registry
  Recruiting · Observational · 100 enrolled · Institute of Hematology & Blood Diseases Hospital, China
  NCT06992076updated 2026-04-29
• Open-Label Extension Study of Marstacimab in Hemophilia Participants With or Without Inhibitors
  Recruiting · Phase 3 · Interventional · 245 enrolled · Pfizer
  NCT05145127updated 2026-04-14
• A Study to Learn About the Study Medicine -Hympavzi in Congenital Hemophilia Patients Without Inhibitors in Japan.
  Active not recruiting · Observational · 50 enrolled · Pfizer
  NCT07161687updated 2026-03-30
• Monitoring of Anti-TFPI in Hemophilia
  Recruiting · Observational · 11 enrolled · Hospices Civils de Lyon
  NCT07101926updated 2026-03-23
• Study of the Efficacy and Safety PF-06741086 in Adult and Teenage Participants With Severe Hemophilia A or Moderately Severe to Severe Hemophilia B
  Completed · Phase 3 · Interventional · 189 enrolled · Pfizer
  NCT03938792updated 2025-06-10
• Study to Evaluate Safety and Tolerability of a Single Dose of PF-06741086 in Chinese Adult Participants With Severe Hemophilia
  Completed · Phase 1 · Interventional · 6 enrolled · Pfizer
  NCT04878731updated 2023-07-07
• A Study of Marstacimab to Compare Prefilled Pen (PFP) Device to Prefilled Syringe (PFS) Device
  Terminated · Phase 1 · Interventional · 22 enrolled · Pfizer
  NCT04832139updated 2022-07-11
• PF-06741086 Long-term Treatment in Severe Hemophilia
  Completed · Phase 2 · Interventional · 20 enrolled · Pfizer
  NCT03363321updated 2021-07-27

Frequently asked questions

How does Marstacimab work?

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.

What is Marstacimab used for?

According to FDA labeling, Marstacimab carries indications including: 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.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Marstacimab?

Marstacimab is classified as Other systemic hemostatics, Antibody Interactions, Increased Coagulation Factor Activity.

What are the brand names for Marstacimab?

Marstacimab is marketed under brand names including Hympavzi.

What are the contraindications for Marstacimab?

Marstacimab labeling lists contraindications including: None. None.. Always consult the full prescribing information and a clinician.