CHICOPEE, Mass. (WWLP)- The FDA has just approved the most expensive drug on the market to date. The drug known as Hemgenix costs $3.5 million per dose and is administered to patients with the rare disorder Hemophilia B.

Hemophilia B is a blood clotting disorder resulting from insufficient amounts of a protein called Protein IX. Hemgenix is a gene therapy drug that is given in one dose via IV infusion. Most patients with Hemophilia B are men and about one in every 40,000 people has the disorder. Women are often carriers, displaying no symptoms but passing the disorder on to their children.

“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, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research. 

Famous people who have had Hemophilia B include Alexei Nikolaevichm, the ill fated only son of Russian Zar Nicholas II who was killed with the rest of his family in 1918 at the start of the Russian Revolution. Richard Burton, actor in movies like Cleopatra and 1984, was one of the first actors to publicly reveal he had Hemophilia.