Etranacogene dezaparvovec

Hemophilia B - also called factor IX deficiency or Christmas disease - is an X-linked genetic disorder resulting in an absence or deficiency of clotting factor IX.^L44176 Clotting factors, including factor IX, are necessary components of the signaling cascade responsible for blood clotting and subsequent wound healing.^L44181 Symptoms of hemophilia B, therefore, involve a heightened susceptibility to bleeding episodes - in mild cases, bleeding may only occur after injury, while in more severe cases bleeding may occur after a minor injury or even spontaneously.^L44181

Hemophilia B is the second most common type of hemophilia,^L44181 with a prevalence of approximately one in 40,000.^L44161 Men are most likely to experience symptomatic illness due to the X-linked provenance of the disorder.^L44161 Treatment of hemophilia B primarily involves the routine replacement of factor IX using recombinant or donor-derived factor IX products that, while effective, may be burdensome for the patient due to the requirement of routine intravenous infusions.L44161,L44181

Etranacogene dezaparvovec (Hemgenix, CSL Bering LLC) is a gene therapy for the treatment of hemophilia B that provides a new treatment modality for its patients. The therapy involves a one-time infusion of a viral vector carrying a codon-optimized DNA sequence of the gain-of-function Padua variant of human Factor IX controlled by a liver-specific promotor 1.^L44156 It delivers a copy of the deficient gene that results in cell transduction and an eventual increase in circulating factor IX activity.^L44156 Etranacogene dezaparvovec was approved by the FDA in November 2022 for the treatment of select patients with hemophilia B, becoming the first gene therapy approved for this indication.^L44161 It is additionally notable for its cost per treatment - approximately 3.5 million USD - earning it the title of most expensive drug in the world.^L44186 In December 2022, the EMA's Committee for Medicinal Products for Human Use (CHMP) recommended etranacogene dezaparvovec be granted marketing authorization for the treatment of severe and moderately severe Haemophilia B.^L45255 Etranacogene dezaparvovec was approved by the EMA in February 2023L45439,L45444 and by Health Canada in October 2023.^L48801