FDA approves treatment for acquired hemophilia

Woodruff Health Sciences Center | Nov. 21, 2014

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Quinn Eastman
404-727-7829
qeastma@emory.edu

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The drug Obizur was developed to treat acquired hemophilia A, one of the blood clotting disorders caused by a deficiency of clotting factor VIII.

On Oct. 24, the Food and Drug Administration approved Obizur, a treatment for acquired hemophilia A. Obizur was originally developed by a research team led by Emory hematologist Pete Lollar. The Obizur technology was licensed by Emory in 1998 to startup company Octagen and eventually brought to commercial availability by the pharmaceutical firm Baxter International.

Lollar is Hemophilia of Georgia Professor of Pediatrics in the Aflac Cancer and Blood Disorders Center at Emory University School of Medicine and Children's Healthcare of Atlanta. The team that developed the drug included Ernest Parker, John Healey and Rachel Barrow, and followed a research collaboration between Lollar and Emory cardiologist Marschall Runge (now at UNC).

Hemophilia is a group of blood clotting disorders leading to excessive bleeding that can occur spontaneously or following injury or surgery. Hemophilia A is caused by a deficiency of clotting factor VIII, and can be either inherited or acquired.

In acquired hemophilia A, the immune system is somehow provoked into making antibodies against factor VIII that inactivate it. Acquired hemophilia is a challenge for doctors to deal with because patients frequently present with severe, life threatening bleeding and also because it's a surprise: patients do not have a previous personal or family history of bleeding episodes. Antibodies to factor VIII also can be a problem for approximately 30 percent of patients with inherited hemophilia.

Lollar's team developed a modified form of factor VIII, derived from the protein sequence of pigs, which is less of a red flag to the immune system. According to the FDA:

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 people with acquired hemophilia A.

The safety and efficacy of Obizur was evaluated in a clinical trial of 29 adults with acquired hemophilia A who received Obizur to treat a serious bleeding episode. The trial demonstrated the effectiveness of Obizur in the treatment of bleeding episodes. No safety concerns were identified in the trial. Obizur received orphan drug designation by the FDA because the drug is intended for use in treatment of a rare disease or condition.

After licensing the technology from Emory, Octagen and a French partner, Ipsen Biopharm, pursued preclinical and clinical studies and completed a phase II clinical trial in 2006. Ipsen purchased the rights to the modified factor VIII in 2008, and developed a partnership with Inspiration Biopharmaceuticals in 2010. The pivotal phase III clinical trial took place between 2010 and 2013, and the rights to what became Obizur were bought by Baxter in 2013.