FDA Approves $3.5 Million Hemophilia B Gene Therapy

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CSL’s Hemgenix (etranacogene dezaparvovec) will cost approximately $3.5 million, making it the most expensive single-use medicine in the United States.

FDA announced the approval of CSL’s Hemgenix (etranacogene dezaparvovec), the first one-time gene therapy for adults with hemophilia B, on Nov. 22, 2022. The treatment is approved for use in adults with hemophilia B who currently use factor IX prophylaxis therapy, or those who have had life-threatening hemorrhage or repeated spontaneous bleeding episodes. The therapy will cost approximately $3.5 million, making it the most expensive single-use therapy in the United States.

According to the agency press release, Hemophilia B is a genetic bleeding disorder resulting from missing or insufficient levels of blood clotting Factor IX, a protein needed to produce blood clots to stop bleeding. In an ongoing clinical trial, etranacogene dezaparvovec reduced the rate of annual bleeds by 54%. Additionally, 94% percent of patients were able to discontinue factor IX prophylaxis and remained prophylaxis-free.

“Gene therapy for hemophilia has been on the horizon for more than two decades. Despite advancements in the treatment of hemophilia, the prevention and treatment of bleeding episodes can adversely impact individuals’ quality of life,” said Peter Marks, director, FDA Center for Biologics Evaluation and Research, in the release. “Today’s approval provides a new treatment option for patients with Hemophilia B and represents important progress in the development of innovative therapies for those experiencing a high burden of disease associated with this form of hemophilia.”


“As part of our promise to patients, CSL is committed to delivering innovative and groundbreaking solutions to address unmet medical needs, and we are proud to introduce the next wave of breakthrough medicines for people living with hemophilia B,” said Paul Perreault, CEO and managing director, CSL, in a company press release. “We recognize and thank all trial participants, scientists and investigators—without whom this important achievement would not have been possible—and look forward to seeing the positive impact of HEMGENIX on the hemophilia B community.”

Source: FDA, CSL