FDA approves recombinant treatment for hemophilia A or B with inhibitors


The Food and Drug Administration has approved a new rabbit-derived recombinant analog of human coagulation factor VII (Sevenfact) for the treatment of hemophilia A or B, according to a release from the agency.

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The treatment’s approval is for use in patients aged 12 years and older who’ve developed inhibitors (neutralizing antibodies). This factor VII (FVII) analog bypasses the FVIII and FIX reactions, which are no longer effective pathways for treatment in these patients because of the inhibitors they’ve developed.

According to the release, “the active ingredient of Sevenfact is a recombinant analog of human FVII, which is expressed in the mammary gland of genetically engineered rabbits and secreted into the rabbits’ milk. During purification and processing of the milk, FVII is converted into activated FVII.” The FDA’s Center for Veterinary Medicine has, after “comprehensive analysis of the scientific evidence,” determined that the process is safe for both the rabbits and handlers and that it is an effective means of producing the coagulation factor.

The approval is based on a clinical study that evaluated 27 patients with hemophilia A or B and included treatment for 465 mild to moderate events and 3 severe ones. The low (75 mcg/kg) or high (225 mcg/kg) dose was able to successfully treat 86% of the mild to moderate episodes, and all three of the severe ones were successfully treated with the high dose.

The most common side effects were headache, dizziness, infusion-site discomfort, infusion-related reaction, infusion-site hematoma, and fever. This product is contraindicated in patients with known allergies or hypersensitivities to rabbits or rabbit proteins. There is potential for increased risk of serious arterial or venous thrombotic events among patients with other risk factors for blood clots. More safety information can be found in the prescribing information, and more information about the approval can be found in the full release.

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