The one-time gene therapy from uniQure and CSL Behring called Hemgenix or etranacogene dezaparvovec-drlb has been approved by the FDA, making it the first Hemophilia B gene therapy to receive the FDA green light. With the approval, it also became the most expensive medicine available around the globe with a price tag of $3.5M.
Hemophilia is a blood clotting disorder that is hereditary and generally rare among the population. It is usually treated using clotting protein factor IX injections. Single gene defect causes inadequate production of clotting factor IX, which in turn causes the bodies of the patients to not be able to stop bleeding by themselves.
Matt Kapusta, the CEO of uniQure, labeled it a historic achievement that is backed by over a decade of R&D. He said that the biggest challenge in the development of the therapy was when the company switched Factor IX variant to the Padua-variant from the wild-type FIX. The change called for reasoning, and the team convinced the FDA that even though the change had a substantial impact on patients, it was not big enough for the trial to be restarted.
Kapusta said that one of the reasons for being the first to bring the product forward is that the team was able to swiftly move to the second generation from the first.
The price point of the medicine is very high, but it is not necessarily unforeseen. Previously, FDA approved two rare illness gene therapies developed by bluebird bio, and both were at comparable prices. Skysona, for CALD (Cerebral Adrenoleukodystrophy), had a price tag of $3M while Zynteglo, for beta-thalassemia, stood at $2.8M.
Hemophilia is predominantly found in the male population with a three-year-old study revealing that there were between 6,994 and 7,751 males with the condition in the United States at the time.
A CSL spokesperson stated, “We are confident this price point will generate significant cost savings for the overall healthcare system and significantly lower the economic burden of hemophilia B.”
CSL paid $500M upfront to uniQure according to the deal terms. Royalties and commercial milestone payments could rise to a maximum of $1.5B.
The approval was based on the data from the biggest Hemophilia B trial till now; Hope-B. The data showed that Hemgenix curtailed the rate of annual bleeds. 94% of the patients stopped factor IX prophylaxis and stayed prophylaxis-free.
Therapy-treated patients had a mean factor IX activity of 39% at half a year and 36.7% at 2 years post-dosing. The mean adjusted ABR (annual bleeding rate) was abridged by 54% in 7 to 18 months post-dosing.
Kapusta said that following this, he is now most excited about the Huntington’s disease gene therapy that the company has in the works. He also said that uniQure has the only AAV gene therapy that is being clinically tested at this point and very significant data will be read out in the coming year.