Treatment for Rare Hemophilia Approved by FDA

The FDA on Thursday approved a new treatment for adults who experience bleeding episodes from a rare and potentially life-threatening form of hemophilia.

Baxter International Inc’s antihemophilic Factor (Recombinant), Porcine Sequence (Obizur) treats acquired hemophilia (AHA), a bleeding disorder caused by the development of antibodies that are directed against a protein that is vital for blood clotting. When the FVIII protein is deactivated by the autoantibodies, the blood doesn’t clot normally and results in excessive bleeding that may occur following an injury or surgery.

The drug 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 of Obizur is welcome news for the hemophilia community based on the data from the first clinical trial designed specifically for acquired hemophilia A, which found that all patients responded to treatment within 24 hours,'' said Rebecca Kruse-Jarres, MD, principal investigator in the drug’s clinical trial, in a press release. ''Importantly, this new option to treat bleeding episodes will enable us to measure factor VIII levels, thus giving us an objective marker of hemostasis that can guide dosing and prevent overdosing.''

The approval of Obizur, which was previously granted orphan drug status by the FDA, follows a global, multi-center, open-label clinical trial that tested the efficacy of the drug in treating serious bleeding episodes of 29 AHA patients who were evaluated for safety and 28 who were evaluated for efficacy.

All 28 patients treated with Obizur had their bleeding stopped or reduced with clinical improvement at 24 hours following the initial infusion. Meanwhile, 24 of the 28 patients had successful treatment of the initial bleeding episode. Approximately 5% of the 29 patients in the safety clinical trial developed inhibitors to porcine FVIII. There were no safety concerns identified in the trial.

''As a new treatment option with the ability to measure FVIII activity in the body, OBIZUR will address important unmet needs for patients with acquired hemophilia A, a potentially life-threatening condition,'' said Brian Goff, head of Baxter's hemophilia franchise, in a press release.