HYMPAVZI® (marstacimab-hncq) 5 WARNINGS AND PRECAUTIONS

(marstacimab-hncq)

Prescribing Information

5 WARNINGS AND PRECAUTIONS

5.1 Thromboembolic Events

HYMPAVZI is a tissue factor pathway inhibitor (TFPI) antagonist, and may increase the risk of thromboembolic complications. Venous and arterial thromboembolic events were reported in 0.8% of patients (2/259) treated with HYMPAVZI in the open-label extension study [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 or bypassing agents are indicated in a patient receiving HYMPAVZI prophylaxis, the minimum effective dose according to the product label is recommended [see Dosage and Administration (2.5)].

5.2 Hypersensitivity

HYMPAVZI may cause hypersensitivity reactions (including but not limited to urticaria and pruritus). If HYMPAVZI-treated patients develop a severe hypersensitivity reaction, advise patients to discontinue HYMPAVZI and seek immediate emergency treatment.

5.3 Embryofetal Toxicity

Based on its mechanism of action, HYMPAVZI may cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)]. Advise pregnant women of the potential risk to the fetus. Advise females of reproductive potential to use effective contraception during treatment with HYMPAVZI and for 2 months after the last dose [see Use in Specific Populations (8.1, 8.3)].

5.4 Increased Laboratory Values of Fibrin D-dimer and Prothrombin Fragment 1.2

Consistent with its mechanism of action and hemostatic effect, HYMPAVZI causes an increase in fibrin D‑dimer and prothrombin fragment 1.2 [see Clinical Pharmacology (12.1, 12.2)]. Sporadic or transient increases in levels of these biomarkers above physiological values were reported with no associated safety concerns [see Clinical Pharmacology (12.2)]. Increased levels of fibrin D-dimer were seen in 10 (8.1%) pediatric patients age 6 to less than 18 years and 6 (4.4%) adults. Increased levels of prothrombin fragment 1.2 were seen in 13 (10.5%) pediatric patients age 6 to less than 18 years and 6 (4.4%) adults. For patients taking HYMPAVZI, these coagulation biomarkers may not be reliable predictive markers for clinical decision-making with suspicion of thrombosis such as deep vein thrombosis (DVT) and pulmonary embolism (PE).

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). • 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: • 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. • have a severe short-term (acute) illness such as an infection or injury. • have been told that you have a risk for blood clots. • 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. • 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. • Use HYMPAVZI exactly as prescribed by your healthcare provider. • 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. • HYMPAVZI comes in two different strengths in a single-dose prefilled syringe or single-dose prefilled pen. • HYMPAVZI is given as an injection under your skin (subcutaneous injection) by you or your caregiver. • 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. • Do not inject yourself or someone else until you have been shown how to inject HYMPAVZI. • Inject HYMPAVZI 1 time a week on the same day each week. Inject HYMPAVZI at any time of day. • 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 o redness or discoloration in your arms or legs o shortness of breath o pain in chest or upper back o fast heart rate o cough up blood		o feel faint o headache o numbness in your face o eye pain or swelling o trouble seeing
• 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 o trouble breathing o wheezing		o dizziness or fainting o fast heartbeat or pounding in your chest o sweating
The most common side effects of HYMPAVZI include:
• swelling, hardening, redness, bruising, bleeding, and pain at injection site • headache • fever		• joint pain • diarrhea • itching • 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? • Store HYMPAVZI in a refrigerator at 36°F to 46°F (2°C to 8°C). • Store HYMPAVZI in the original carton to protect from light. • 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. • Throw away (dispose of) HYMPAVZI that has been left out of the refrigerator for more than 7 days. • Do not freeze HYMPAVZI. • 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. 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.

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