Rare Daily Staff
UniQure said it has enrolled the first patient in its pivotal, late-stage study of AMT-061, an experimental gene therapy to treat hemophilia B.
Hemophilia B is a rare genetic bleeding disorder that results in a deficiency of factor IX, a blood clotting factor. People with hemophilia B are at risk for excessive and recurrent bleeding from modest injuries, which have the potential to be life-threatening. In severe cases, people with the condition can bleed spontaneously into their muscles or joints. In rare cases, they can bleed into the intracranial space, where bleeding can be fatal.
AMT-061 consists of an AAV5 viral vector carrying a gene cassette with the Padua variant of Factor IX (FIX-Padua). FIX-Padua has been reported to provide an approximate 8 to 9-fold increase in FIX activity compared to the wild-type FIX protein, as used in the company’s earlier version AMT-060. AAV5-based gene therapies have been demonstrated to be safe and well-tolerated in multiple clinical trials, including three UniQure trials conducted in 22 patients in hemophilia B and other indications.
The phase 3 HOPE-B pivotal trial is a multinational, multi-center, open-label, single-arm study to evaluate the safety and efficacy of AMT-061. Approximately 50 adult hemophilia B patients classified as severe or moderately severe will be enrolled in a six-month observational period during which time they will continue to use their current standard of care to establish a baseline control. After the six-month lead-in period, patients will receive a single intravenous administration of AMT-061. Dosing of patients in the HOPE-B pivotal trial is expected to start early in the first quarter of 2019.
The primary endpoint of the study will be based on the Factor IX activity level achieved following the administration of AMT-061, and the secondary endpoints will measure annualized FIX replacement therapy use rate and annualized bleed rate.
“AMT-061 has the potential to be a major advancement in gene therapy for patients affected by hemophilia B,” said Steven Pipe, professor of pediatrics and pathology and pediatric medical director of the hemophilia and coagulation disorders program at the University of Michigan and principal investigator of the HOPE-B clinical trial. “A one-time treatment, such as AMT-061, could be life-changing for these patients, many of whom struggle to manage ongoing challenges, including compliance with frequent infusions and recurrent episodes of bleeding.”
AMT-061 has been granted Breakthrough Therapy designation by the U.S. Food and Drug Administration and access to the Priority Medicines (PRIME) regulatory initiative by the European Medicines Agency.
June 28, 2019
Photo: Steven Pipe, principal investigator of the HOPE-B clinical trial