The treatment is now available in the US. The US Food and Drug Administration (FDA) has approved the most expensive drug in the world: Hemgenix, a gene therapy treatment for the rare genetic disease hemophilia B. Hemophilia B is a rare bleeding disorder, caused by the lack of a blood protein called Factor IX. Treatments are available for the disorder, including regular intravenous infusions to help with clotting and prevent bleeding episodes. These treatments themselves are incredibly expensive over a lifetime. "Total adult lifetime costs per patient with severe and moderately severe [hemophilia B] were $21,086,607 for [standard half-life Factor IX] prophylaxis, $22,987,483 for [extended half-life Factor IX] prophylaxis, and $20,971,826 for on-demand [Factor IX] treatment," one study published in the Journal of Medical Economics found, calling it a "significant economic burden". This new therapy, created by pharmaceutical company CSL Behring, is a gene therapy that can be given as a single dose to cover your lifetime. "Hemgenix consists of a viral vector carrying a gene for clotting Factor IX," the FDA explains in a statement. "The gene is expressed in the liver to produce Factor IX protein, to increase blood levels of Factor IX and thereby limit bleeding episodes. " Studies found that the therapy cuts the bleeding rate in patients by 54 percent compared to their baseline annual bleed rate. “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,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in the statement about Tuesday's approval. “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.” Though the drug is cheaper than the cost of other treatments over a patient's lifetime, it still costs a hefty $3.5 million, making it the most expensive drug in the world. The price is a concern, though some analysts believe the nature of the condition may make patients take the treatment anyway. “While the price is a little higher than expected, I do think it has a chance of being successful because 1) existing drugs are also very expensive and 2) hemophilia patients constantly live in fear of bleeds,” biotechnology investor and CEO of Loncar Investments Brad Loncar told Bloomberg. Source