uniQure recently announced that their investigational hemophilia B gene therapy, AMT-060, has received “breakthrough” therapy designation from the U.S. Food and Drug Administration (FDA). UniQure is an Amsterdam-based company specializing in developing gene therapies to treat rare conditions, such as central nervous system disorders, liver/metabolic and cardiovascular diseases. Breakthrough drugs are put on a fast-track approval program and given intensive guidance from the FDA.

The technology behind AMT-060 employs adeno-associated viruses (AAV). These small viruses, which do not cause disease and typically produce mild immune responses, are used as vectors (delivery vehicles) to introduce a functioning factor IX (FIX) gene into the liver cells of patient’s with hemophilia B. The goal of the trial is to trigger long-term FIX protein production through a single administration of the therapy. This could dramatically reduce the frequency of bleeding episodes in people with hemophilia B.

Breakthrough designation was achieved in light of new data from an ongoing phase I/II clinical trial, which were presented at the 58th Annual Meeting of the American Society of Hematology in December 3-6, 2016. The trial divided 10 people with hemophilia B into two groups: five received a low-dose intravenous administration of AMT-060 and five received a considerably higher dose. The new data include up to 52 weeks of follow-up from the low-dose group and up to 31 weeks of follow-up from the high-dose group.

The new data from the high-dose group showed a dose response indicating a significant improvement in disease state in all five patients. This prompted the discontinuation of precautionary FIX infusions in all four patients who had previously required chronic replacement therapy. To date, only one spontaneous bleed was reported after discontinuation of prophylactic FIX therapy. In addition, all five patients in the low-dose group whose bleeds were previously uncontrolled despite being managed with prophylactic therapy, continue to maintain “robust, constant and clinically meaningful” levels of FIX activity for up to 52 weeks post treatment, with a cessation of spontaneous bleeds in the last 14 weeks of observation.

“We are very pleased the FDA has designated AMT-060 a Breakthrough Therapy for patients with hemophilia B,” stated Matthew Kapusta, chief executive officer of uniQure.  “The FDA’s decision to prioritize and expedite the review of AMT-060 is an important milestone for uniQure and we are committed to working closely with the FDA to rapidly advance our hemophilia B program into late-stage development.”

Source: uniQure press release dated January 30, 2017