US regulators have approved Baxter’s Obizur (antihaemophilic factor, porcine sequence), for the treatment of bleeding episodes in adults with the rare condition acquired haemophilia A.

The potentially life-threatening bleeding disorder is caused by the development of antibodies against the body’s own blood clotting mechanisms, leaving patients at risk from excessive bleeding episodes.

Unlike inherited haemophilia, acquired haemophilia A is not a genetic disorder and affects both males and females. Its development is sometimes linked to other medical conditions or health states, such as pregnancy, cancer, or the use of certain medications, but in around half of causes the underlying cause cannot be detected.

Obizur is the first recombinant porcine FVIII treatment approved for the disorder that allows physicians to manage its efficacy and safety by measuring factor VIII activity levels in addition to clinical assessments. Porcine FVIII is used because it is similar enough to human FVIII to be effective in blood clotting, but is less likely to be affected by the antibodies against human FVIII that are present in patients, the regulator noted.

Welcome news

"The approval of Obizur is welcome news for the haemophilia community based on the data from the first clinical trial designed specifically for acquired haemophilia A, which found that all patients responded to treatment within 24 hours," commented Rebecca Kruse-Jarres, Director of the Haemophilia Care Program at Puget Sound Blood Center in Seattle and the clinical trial's principal investigator. 

"Importantly, this new option to treat bleeding episodes will enable us to measure factor VIII levels, thus giving us an objective marker of haemostasis that can guide dosing and prevent overdosing,” she added.

According to Baxter, the drug will be commercially available in the US “in the coming months”, and it is also under the regulatory microscope in Europe and Canada.