(marstacimab-hncq)

Prescribing Information
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HIGHLIGHTS OF PRESCRIBING INFORMATION

HIGHLIGHTS OF PRESCRIBING INFORMATION

These highlights do not include all the information needed to use HYMPAVZI safely and effectively. See full prescribing information for HYMPAVZI.

HYMPAVZI® (marstacimab-hncq) injection, for subcutaneous use
Initial U.S. Approval: 2024

RECENT MAJOR CHANGES

Indications and Usage (1)

06/2026

Dosage and Administration (2.2, 2.5, 2.8)

06/2026

Warnings and Precautions, Increased Laboratory Values of Fibrin D-dimer and Prothrombin Fragment 1.2 (5.4)

06/2026

INDICATIONS AND USAGE

HYMPAVZI is a tissue factor pathway inhibitor (TFPI) antagonist indicated for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adults and pediatric patients 6 years of age and older with:

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hemophilia A (congenital factor VIII deficiency) with or without factor VIII inhibitors, or
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hemophilia B (congenital factor IX deficiency) with or without factor IX inhibitors. (1)

DOSAGE AND ADMINISTRATION

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See Full Prescribing Information for important dosing and administration instructions. (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8)
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Recommended Dosage in Adults and Pediatric Patients 12 Years of Age and Older:
o
Loading dose: 300 mg (two 150 mg injections) by subcutaneous injection. (2.1)
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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)
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Dose adjustment to 300 mg subcutaneous injection weekly can be considered. (2.1)
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Recommended Dosage in Pediatric Patients 6 to less than 12 Years of Age:
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Loading dose: 150 mg (one 150 mg injection or two 75 mg injections) by subcutaneous injection. (2.2)
o
Maintenance dose: One week after the loading dose, initiate maintenance dosing of 75 mg every week by subcutaneous injection on the same day each week, at any time of day. (2.2)
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Dose adjustment to 150 mg subcutaneous injection (one 150 mg injection or two 75 mg injections) weekly can be considered. (2.2)
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Factor VIII and factor IX products or bypassing agents (e.g., rFVIIa or aPCC) can be administered for the treatment of breakthrough bleeds in patients receiving HYMPAVZI. Do not use additional doses of HYMPAVZI to treat breakthrough bleeds. (2.5)
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Temporarily pause HYMPAVZI at least 7 days before major surgery. (2.6)

DOSAGE FORMS AND STRENGTHS

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Injection: 150 mg/mL and 75 mg/0.5 mL in a single-dose prefilled syringe (3)
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Injection: 150 mg/mL and 75 mg/0.5 mL in a single-dose prefilled pen (3)

CONTRAINDICATIONS

None. (4)

WARNINGS AND PRECAUTIONS

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Thromboembolic Events: Thromboembolic events may occur. Interrupt HYMPAVZI prophylaxis if symptoms occur. (5.1)
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Hypersensitivity: Hypersensitivity reactions may occur. In the event of a severe allergic reaction, discontinue HYMPAVZI. (5.2)
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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)
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Increased Laboratory Values of Fibrin D-dimer and Prothrombin Fragment 1.2: HYMPAVZI can cause sporadic or transient increases in fibrin D-dimer and prothrombin fragment 1.2 above physiological values. (5.4)

ADVERSE REACTIONS

Adverse reactions reported in ≥2% of HYMPAVZI-treated patients were injection site reaction, headache, pyrexia, arthralgia, diarrhea, pruritus, and rash. (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.

See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling.

Revised: 6/2026

Medication Guide

MEDICATION GUIDE

     

This Patient Information has been approved by the U.S. Food and Drug Administration.          Revised: 6/2026

PATIENT INFORMATION

HYMPAVZI® (him-PAV-zee)

(marstacimab-hncq)

injection, for subcutaneous use

Important information:

•
Before you start using HYMPAVZI, it is very important to talk to your healthcare provider about using factor VIII and factor IX products or bypassing agents (products that help blood clot but work in a different way than HYMPAVZI).
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Your healthcare provider may prescribe factor VIII, factor IX medicines, or bypassing agents to treat episodes of breakthrough bleeding during your treatment with HYMPAVZI. Carefully follow your healthcare provider’s instructions regarding when to use these medicines and the prescribed dose during your treatment with HYMPAVZI. Do not use additional doses of HYMPAVZI to treat breakthrough bleeds.

What is HYMPAVZI?

HYMPAVZI is a prescription medicine used regularly to prevent or reduce the frequency of bleeding episodes in adults and children 6 years of age and older with:

•
hemophilia A with or without factor VIII inhibitors, or
•
hemophilia B with or without factor IX inhibitors.

It is not known if HYMPAVZI is safe and effective in people receiving ongoing Immune Tolerance Induction (ITI).

It is not known if HYMPAVZI is safe and effective in children younger than 6 years of age.

Before using HYMPAVZI, tell your healthcare provider about all of your medical conditions, including if you:

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have a planned surgery. Your healthcare provider may stop treatment with HYMPAVZI before your surgery. Talk to your healthcare provider about when to stop using HYMPAVZI and when to start it again if you have a planned surgery.
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have a severe short-term (acute) illness such as an infection or injury.
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have been told that you have a risk for blood clots.
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are pregnant or plan to become pregnant. HYMPAVZI may harm your unborn baby.
 
Females who are able to become pregnant:
o
Your healthcare provider will do a pregnancy test before you start your treatment with HYMPAVZI.
o
Use effective birth control (contraception) during treatment with HYMPAVZI and for 2 months after the last dose of HYMPAVZI.
o
Tell your healthcare provider right away if you become pregnant or think that you may be pregnant during treatment with HYMPAVZI.
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are breastfeeding or plan to breastfeed. It is not known if HYMPAVZI passes into your breast milk.

Tell your healthcare provider about all the medicines you take, including prescription medicines, over‑the‑counter medicines, vitamins, and herbal supplements.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

How should I use HYMPAVZI?

See the detailed “Instructions for Use” that comes with your HYMPAVZI for information on how to inject a dose of HYMPAVZI, and how to properly throw away (dispose of) used HYMPAVZI prefilled syringe or HYMPAVZI prefilled pen.

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Use HYMPAVZI exactly as prescribed by your healthcare provider.
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Your healthcare provider will provide instructions for stopping (discontinuing) your current treatment when switching from factor- or non-factor-based medicines or bypassing agents to HYMPAVZI.
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HYMPAVZI comes in two different strengths in a single-dose prefilled syringe or single-dose prefilled pen.
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HYMPAVZI is given as an injection under your skin (subcutaneous injection) by you or your caregiver.
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People 12 years of age and older, or their caregiver may inject HYMPAVZI if your healthcare provider decides that it is appropriate. Your healthcare provider should show you or your caregiver how to inject HYMPAVZI before the first injection.
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Do not inject yourself or someone else until you have been shown how to inject HYMPAVZI.
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Inject HYMPAVZI 1 time a week on the same day each week. Inject HYMPAVZI at any time of day.
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Dosing for adults and children 12 years of age and older:
o
Your first dose (loading dose) of HYMPAVZI is 300 mg (two 150 mg injections). Then you will inject a weekly (maintenance) dose as prescribed by your healthcare provider.
o
If you miss a maintenance dose of 150 mg of HYMPAVZI:
▪
Give the dose as soon as possible before the day of your next scheduled dose, and then continue with your usual weekly dosing schedule. You may inject your next dose at your regularly scheduled time or continue dosing based on the new day you injected your missed dose. In case you are not sure when to inject HYMPAVZI, call your healthcare provider.
▪
If more than 13 days have passed since your last dose was given, you will need to restart with a loading dose. Call your healthcare provider right away for dosing instructions.
o
If you miss 1 or more doses of maintenance dose of 300 mg of HYMPAVZI:
▪
Give a dose as soon as possible, and then continue with your usual weekly dosing schedule. You may inject your next dose at your regularly scheduled time or continue dosing based on the new day you injected your missed dose. In case you are not sure when to inject HYMPAVZI, call your healthcare provider.
•
Dosing for children 6 years to less than 12 years of age:
o
Your first dose (loading dose) of HYMPAVZI is 150 mg (one 150 mg injection or two 75 mg injections) as prescribed by your healthcare provider. Then you will inject a weekly (maintenance) dose as prescribed by your healthcare provider.
o
If you miss a maintenance dose of 75 mg of HYMPAVZI:
▪
Give the dose as soon as possible before the day of your next scheduled dose, and then continue with your usual weekly dosing schedule. You may inject your next dose at your regularly scheduled time or continue dosing based on the new day you injected your missed dose. In case you are not sure when to inject HYMPAVZI, call your healthcare provider.
▪
If more than 13 days have passed since your last dose was given, you will need to restart with a loading dose. Call your healthcare provider right away for dosing instructions.
o
If you miss 1 or more doses of maintenance dose of 150 mg of HYMPAVZI:
▪
Give a dose as soon as possible, and then continue with your usual weekly dosing schedule. You may inject your next dose at your regularly scheduled time or continue dosing based on the new day you injected your missed dose. In case you are not sure when to inject HYMPAVZI, call your healthcare provider.
•
If you inject too much HYMPAVZI, call your healthcare provider or the Poison Help Line at 1-800-222-1222 or go to the nearest hospital emergency room right away.

What are the possible side effects of HYMPAVZI?

HYMPAVZI may cause serious side effects, including:

•
blood clots (thromboembolic events). HYMPAVZI may increase the risk for your blood to clot in blood vessels in your arm, leg, lung, or head and can be life-threatening. Blood clots have happened in people using HYMPAVZI. You may have an increased risk of blood clots if you have certain risk factors. Stop using HYMPAVZI and get medical help right away if you develop any of these signs or symptoms of blood clots:
o
swelling or pain in arms or legs
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redness or discoloration in your arms or legs
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shortness of breath
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pain in chest or upper back
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fast heart rate
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cough up blood
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feel faint
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headache
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numbness in your face
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eye pain or swelling
o
trouble seeing
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allergic reactions. HYMPAVZI may cause allergic reactions, including rash and itching. Stop using HYMPAVZI and get medical help right away if you develop any of the following symptoms of a severe allergic reaction:
o
swelling of your face, lips, mouth, or tongue
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trouble breathing
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wheezing
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dizziness or fainting
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fast heartbeat or pounding in your chest
o
sweating

The most common side effects of HYMPAVZI include:

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swelling, hardening, redness, bruising, bleeding, and pain at injection site
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headache
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fever
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joint pain
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diarrhea
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itching
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rash

These are not all of the possible side effects of HYMPAVZI.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How should I store HYMPAVZI?

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Store HYMPAVZI in a refrigerator at 36°F to 46°F (2°C to 8°C).
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Store HYMPAVZI in the original carton to protect from light.
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If needed, HYMPAVZI may be stored one time at room temperature up to 86°F (30°C) in its original carton for up to 7 days. Do not return HYMPAVZI to the refrigerator after storing at room temperature.
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Throw away (dispose of) HYMPAVZI that has been left out of the refrigerator for more than 7 days.
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Do not freeze HYMPAVZI.
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Do not shake HYMPAVZI.

Keep HYMPAVZI and all medicines out of the reach of children.

General information about the safe and effective use of HYMPAVZI.

Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use HYMPAVZI for a condition for which it was not prescribed. Do not give HYMPAVZI to other people, even if they have the same symptoms that you have. It may harm them. You can ask your pharmacist or healthcare provider for information about HYMPAVZI that is written for health professionals.

What are the ingredients in HYMPAVZI?

Active ingredient: marstacimab‑hncq

Inactive ingredients: edetate disodium, histidine, L-histidine monohydrochloride, polysorbate 80, sucrose, and water for injection

This product's labeling may have been updated. For the most recent prescribing information, please visit www.pfizer.com.

Pfizer logo
US License No. 2001
Distributed by: Pfizer Labs, Division of Pfizer Inc., New York, NY 10001
LAB-1575-3.0
For more information, go to website www.HYMPAVZI.com or call 1-800-438-1985.

Additional Resources

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Submit a medical question for a Pfizer medicine or a vaccine. 

The submission will be reviewed during our standard business hours.

To report an adverse event related to a Pfizer product and you are not part of a clinical trial* for this medication, click the link below to submit your information: 
Pfizer Safety Reporting Site

*If you are involved in a clinical trial for either product, adverse events should be reported to your coordinating study site.

If you cannot use the above website to report an adverse event related to a Pfizer medication, please call (800) 438-1985.

You may also contact the U.S. Food and Drug Administration (FDA) directly to report adverse events or product quality concerns either online at www.fda.gov/medwatch or by calling (800) 332-1088.