FDA has approved Antihemophilic Factor (Recombinant), Porcine Sequence] (Obizur, Baxter) for the treatment of bleeding episodes in adults with acquired hemophilia A.
Acquired hemophilia A is a rare, but potentially life-threatening, bleeding disorder caused by the development of antibodies directed against the body’s own FVIII, a protein important for blood clotting. When FVIII is inactivated by these autoantibodies, a person’s blood doesn’t clot normally, resulting in excessive bleeding that can occur spontaneously or following an event such as injury or surgery.
“The FDA approval of Obizur offers an important, and often life-changing, treatment option for those patients diagnosed a rare form of hemophilia,” according to Abimbola Farinde, PharmD, MS, who serves on the faculty at Columbia Southern University, Orange Beach, Ala.
Obizur was granted orphan-drug status by FDA and its review was prioritized based on hemophilia A’s classification as a rare disease and the potential for the treatment to address an important unmet medical need.
Obizur is the first recombinant porcine (pig) FVIII treatment approved for AHA that allows physicians to manage the treatment's efficacy and safety by measuring factor VIII activity levels in addition to clinical assessments. Obizur replaces the inhibited human factor VIII with a recombinant porcine sequence factor VIII based on the rationale that it is less susceptible to inactivation by circulating human factor VIII antibodies.
The approval is based on a global, prospective, controlled, multicenter phase 2/3 open-label clinical trial that examined the efficacy of Obizur in the treatment of serious bleeding episodes in adults with hemophilia A (29 patients evaluated for safety, 28 evaluated for efficacy). All patients treated with Obizur (28/28) showed a positive response, meaning an effective or partially effective response with bleeding stopped or reduced and clinical improvement, at 24 hours after the initial infusion. Eighty-six percent (24/28) had successful treatment of the initial bleeding episode. The overall treatment success was determined by the investigator based on the ability to discontinue or reduce the dose and/or dosing frequency of Obizur. Common adverse reactions observed in greater than 5% of 29 patients in the clinical trial were development of inhibitors to porcine FVIII.
Obizur will be commercially available in the United States in the coming months and is currently under regulatory review in Europe and Canada.