Obizur (factor VIII) is a clotting factor replacement that's infused through the veins to treat bleeding episodes in adults with an autoimmune blood condition called acquired hemophilia A. It's typically given at a hospital that's designated as a hemophilia treatment center. How long your treatment is depends on things like your health status and how serious your bleed is. Obizur (factor VIII) doesn't treat the inherited form of this blood condition (congenital hemophilia A) like other similar medications do. Obizur (factor VIII) doesn't have many known side effects.
Bleeding in adults with acquired hemophilia A (AHA)
Obizur (factor VIII) is a coagulation (clotting) factor replacement for adults with acquired hemophilia A who have problems with their clotting factor VIII (FVIII). Clotting factors are proteins in the blood that help control bleeding.
Obizur (factor VIII) works by temporarily replacing factor FVIII in the blood. As a result, the medication helps control bleeds in people who have low levels of functioning factor VIII that's naturally found in the blood.
Source: DailyMed
Side effects that you should report to your care team as soon as possible:
Works well to treat bleeding episodes in adults with acquired hemophilia A
Only medication that directly replaces FVIII approved for the treatment of bleeding in AHA
Few known side effects
Provider can tailor additional doses based on your response to treatment and your FVIII levels (no "one-size-fits-all")
Can't give to yourself at home
Can't use to prevent bleeding episodes from happening (can only treat current bleeding episodes)
Not for people with allergy to hamsters; can cause allergic reactions since it's lab-made using genetically-engineered hamster cells
Unknown if safe during pregnancy or while breastfeeding
During treatment, your provider will check that your bleeding is improving. Your provider will also check your blood work to make sure that Obizur (factor VIII) is helping to bring your factor VIII levels back to normal.
Let your provider know right away if you have any problems or allergic reactions after your Obizur (factor VIII) infusion. These reactions can include chest tightness, trouble breathing, wheezing, itchy skin, hives, or lightheadedness. Your provider will probably need to stop the infusion and treat your symptoms right away.
Obizur (factor VIII) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Hamster allergy
Rarely, Obizur (factor VIII) can cause allergic reactions, which can be serious. Sometimes, these reactions can lead to life-threatening situations like anaphylaxis, which can include the closing of the throat. Get medical help right away if you experience chest tightness, shortness of breath, wheezing, swelling, or rash.
There's a chance that Obizur (factor VIII) can stop working well for you even though it worked well when you first started treatment. In a clinical study, nearly 1 out of 4 (26%) people who were treated with Obizur (factor VIII) developed inhibitory antibodies to the medication. These antibodies are proteins that can attach to the medication and make it work less well.
Your provider will keep track of how well Obizur (factor VIII) seems to be working for you during treatment. If you seem to stop responding to the medication, your provider might suspect that you've developed antibodies against the medication and might treat your bleeding another way.
This medication is given as an infusion through the veins (intravenously or IV). It must be given by a healthcare provider in a hospital or emergency care setting that's designated as a hemophilia treatment center.
Your provider will calculate your starting dose based on your body weight; the typical starting dose is 200 units/kg of weight.
Any following doses of Obizur (factor VIII) are given every 4 to 12 hours. How often the medication is given depends on how serious your bleed is, your response to the medication, and the FVIII levels in your blood (to make sure they're reaching a particular range that's safe for you).
Allergies to hamsters
Congenital hemophilia A with inhibitors
To treat or prevent bleeds in people with certain types of von Willebrand disease (VWD) and hemophilia A
To treat or control bleeding in people with hemophilia A or hemophilia B with inhibitors
Hemophilia A and B with inhibitors
Glanzmann thrombasthenia where platelet transfusions didn't work well
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bleedingdisorders.com. (n.d.). A quick look at bleeding disorders & coagulation.
Centers for Disease Control and Prevention. (n.d.). Division of Blood Disorders Gateway.
Centers for Disease Control and Prevention. (2022). Treatment of hemophilia.
Centers for Disease Control and Prevention. (2023). Testing for inhibitors and hemophilia.
Mahlangu, J. N., et al. (2017). Recombinant B-domain-deleted porcine sequence factor VIII (r-pFVIII) for the treatment of bleeding in patients with congenital haemophilia A and inhibitors. Haemophilia.
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National Bleeding Disorders Foundation. (n.d.). Hemophilia A.
National Human Genome Research Institute. (2023). Genetic engineering.
National Human Genome Research Institute. (2023). Recombinant DNA technology.
National Organization for Rare Disorders. (2022). Acquired hemophilia.
National Organization for Rare Disorders. (2023). Hemophilia A.
Takeda Pharmaceuticals America, Inc. (2023). Obizur (antihemophilic factor- recombinant, porcine sequence kit) [package insert]. DailyMed.
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