Alprolix® [Coagulation Factor IX (Recombinant), Fc Fusion Protein] logo
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Man with rolling suitcase outdoors (patient portrayal)

ALPROLIX®
Side effects and safety

Bleed protection* with a proven safety profile

For over 10 years, ALPROLIX has been a trusted choice for people living with hemophilia B

*ALPROLIX has been proven to help prevent bleeding episodes in people using prophylaxis.

Most common side effects (≥1%)

1.3%

Previously treated adults, adolescents, and kids

  • Headache
  • Mouth numbness or tingling
  • Urinary blockage

3%

Previously untreated kids

  • Injection site redness and irritation
  • Allergic reactions
  • Factor IX inhibitors
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Contraindications

ALPROLIX should not be used by people who have a known history of allergic reactions, including anaphylaxis, to the product or its inactive ingredients

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Allergic reactions

Allergic reactions may occur with ALPROLIX. Call your healthcare provider or get emergency treatment right away if you have any of the following symptoms: hives, chest tightness, wheezing, difficulty breathing, or swelling of the face

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Formation of inhibitors

Your body can also make antibodies called “inhibitors” against ALPROLIX, which may stop ALPROLIX from working properly. Your healthcare provider should continue to monitor you for inhibitors with blood tests. If you have developed inhibitors with the use of another factor IX therapy, you may be at an increased risk of anaphylaxis with the use of ALPROLIX

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Blood clots

ALPROLIX may increase the risk of formation of abnormal blood clots in your body, especially if you have risk factors for developing blood clots. Call your healthcare provider or seek emergency care if you have symptoms of a possible abnormal blood clot, which may include chest pain, difficulty breathing, unexpected swelling of an arm or leg with or without pain or tenderness

"Since starting ALPROLIX...I am grateful I have the protection from bleeds I need."
—CJ, treating with ALPROLIX since 2014
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Patient CJ
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Important Safety Information and Indication
INDICATION
IMPORTANT SAFETY INFORMATION
INDICATION
ALPROLIX® [Coagulation Factor IX (Recombinant), Fc Fusion Protein] is an injectable medicine that is used to help control and prevent bleeding in people with hemophilia B. Hemophilia B is also called congenital Factor IX deficiency. Your healthcare provider may give you ALPROLIX when you have surgery.
IMPORTANT SAFETY INFORMATION
Do not use ALPROLIX if you are allergic to ALPROLIX or any of the other ingredients in ALPROLIX.

Tell your healthcare provider if you have or have had any medical problems, take any medicines, including prescription and non-prescription medicines, supplements, or herbal medicines, have any allergies and all your medical conditions, including if you are pregnant or planning to become pregnant, are breastfeeding, or have been told you have inhibitors (antibodies) to Factor IX.

Common side effects of ALPROLIX include headache, abnormal sensation in the mouth, and pain in your side with blood in your urine, which may be a sign of clot formation in the urinary collecting system.

Allergic reactions may occur with ALPROLIX. Call your healthcare provider or get emergency treatment right away if you have any of the following symptoms: hives, chest tightness, wheezing, difficulty breathing, or swelling of the face.

Redness to the skin at the injection site may also occur.

ALPROLIX may increase the risk of formation of abnormal blood clots in your body, especially if you have risk factors for developing blood clots. Call your healthcare provider or seek emergency care if you have symptoms of a possible abnormal blood clot, which may include: chest pain, difficulty breathing, unexpected swelling of an arm or leg with or without pain or tenderness.

Your body can also make antibodies called "inhibitors" against ALPROLIX, which may stop ALPROLIX from working properly.

These are not all of the possible side effects of ALPROLIX. Talk to your healthcare provider right away about any side effect that bothers you or does not go away, or if bleeding is not controlled using ALPROLIX.
© 2025 Sanofi. All rights reserved. ALPROLIX, Sanofi, and HemAssist are trademarks or registered trademarks of Sanofi or an affiliate. All the other trademarks above are the property of their respective owners, who have no affiliation or relationship with Sanofi. MAT-US-2021804-v9.0-10/2025 Last updated: October 2025