Generic name: marstacimab [ mar-STAK-i-mab ]
Brand name: Hympavzi Pre-filled Pen
Dosage form: subcutaneous solution (hncq 150 mg/mL)
Drug class: Miscellaneous coagulation modifiers

Medically reviewed by Drugs.com on Feb 4, 2025. Written by Cerner Multum.

What is marstacimab?

Marstacimab is used in adults and children at least 12 years old with hemophilia A or B (without inhibitors) to help prevent bleeding episodes or make them occur less often.

Your doctor will make sure you can be treated with marstacimab.

Marstacimab may also be used for purposes not listed in this medication guide.

Marstacimab side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Marstacimab may cause serious side effects. Call your doctor at once if you have:

• fast or pounding heartbeats;

• chest or back pain, feeling short of breath, coughing up blood;

• swelling, pain, redness, or skin discoloration in your arms or legs;

• headache, dizziness, fainting, sweating;

• numbness in your face; or

• eye pain or swelling, vision problems.

Common side effects of marstacimab may include:

• pain, bruising, swelling, redness, itching, irritation or hardening where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Marstacimab can cause unwanted blood clots, especially if you also use other medicines to help your blood clot.

Before taking this medicine

Tell your doctor if you also use factor or non-factor based medicines. Your healthcare provider will provide instructions for stopping your current treatment when switching to marstacimab.

Tell your doctor if you have or have ever had:

• a planned surgery;

• serious infection, sepsis (a severe reaction to an infection); or

• recent injury or trauma.

May harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant. Use effective birth control while using marstacimab and for at least 2 months after your last dose. Tell your doctor if you become pregnant.

Ask a doctor if it is safe to breastfeed while using marstacimab.

How should I use marstacimab?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Marstacimab is injected under the skin, usually once every week.

Your healthcare provider will show you where to inject marstacimab. Do not inject into the same place two times in a row.

Prepare an injection only when you are ready to give it. Call your pharmacist if the medicine looks cloudy, has changed colors or has particles in it.

Throw away a prefilled syringe after one use, even if there is still medicine left inside.

If you need surgery, tell the surgeon ahead of time that you are using marstacimab. You will need to stop using the medicine for a short time.

Do not use marstacimab to treat breakthrough bleeding. You may be given other medicines to treat breakthrough bleeding during treatment with marstacimab. Follow your doctor's instructions very carefully.

Call your doctor if your symptoms do not improve, or if they get worse.

Store this medicine in the original container in the refrigerator. Protect from light and do not freeze or shake the medicine.

Do not warm the medicine with hot water, sunlight, or a microwave.

Take the medicine out of the refrigerator and let it reach room temperature before using.

You may store this medicine at room temperature for up to 7 days. Throw the medicine away if not used within 7 days. Do not put it back into the refrigerator.

Marstacimab dosing information

Usual Adult Dose for Bleeding:

Loading dose: 300 mg subcutaneously (two 150 mg injections)
Maintenance dose: 150 mg subcutaneously every week

Comments:
-The dose may be increased to 300 mg every week for patients weighing 50 kg or more if bleeding control is inadequate. Safety and efficacy at doses above 300 mg every week have not been established.

Use: To prevent or reduce the frequency of bleeding episodes in patients with hemophilia A or B without inhibitors

Usual Pediatric Dose for Bleeding:

12 years or older:
Loading dose: 300 mg subcutaneously (two 150 mg injections)
Maintenance dose: 150 mg subcutaneously every week

Comments:
-The dose may be increased to 300 mg every week for patients weighing 50 kg or more if bleeding control is inadequate. Safety and efficacy at doses above 300 mg every week have not been established.

Use: To prevent or reduce the frequency of bleeding episodes in patients aged 12 years and older with hemophilia A or B without inhibitors

What happens if I miss a dose?

Use the medicine as soon as you remember, and then go back to your regular schedule. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using marstacimab?

Do not inject into areas where the skin is tender, bruised, red, or hard. Avoid injecting into skin that has scars or stretch marks.

What other drugs will affect marstacimab?

Other drugs may affect marstacimab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Biological Products Related to marstacimab

Find detailed information on biosimilars for this medication.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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