uniQure’s gene therapy shows promise in Hemophilia B treatmentPublished: May 13, 2019
Amsterdam-based gene therapy company uniQure has announced 6-month clinical data of its AAV5-based gene therapy trial for treating patients with severe and moderately severe hemophilia B, a rare genetic bleeding disorder.
The ongoing Phase 2b clinical trial is designed to determine the safety and kinetics of a single intravenous infusion of AMT-061 in Hemophilia B patients. AMT-061 is a recombinant AAV5 vector carrying a patent-protected Padua variant of Factor IX (FIX-Padua). Factor IX is a blood clotting protein which is deficient in Hemophilia patients.
3 patients with severe hemophilia (endogenous FIX activity less than 1%) were enrolled in the study and received a single intravenous infusion of AMT-061 at a dose of 2×1013 vc/kg. Updated data presented at the Hemostasis & Thrombosis Research Society Scientific Symposium last week showed clinically significant increase in Factor IX activity in all three patients up to six months after a single dose of AMT-061.
Mean FIX activity for the three patients at six months increased to 47% (ranging from 33% to 57%) of normal, exceeding threshold FIX levels generally considered enough to eliminate or significantly reduce the risk of bleeding events. Two of the three patients have now achieved FIX activity in the normal range. No patient experienced any bleeding event or serious adverse events.
The levels were also higher than at the six- (31%) and 12-(38%) week study points. If it continues, Factor IX levels are expected to hit 43%-64% in the first year, 50%-75% in the second year and 53%-80% beyond that.
uniQure had previously used the wild-type FIX for gene therapy, however following the lower effect observed with wild-type FIX, it had reached an agreement with FDA to switch the transgene from wild-type FIX to FIX-Padua, which gives rise to much higher levels of expression of factor IX protein.
Patients will be followed for 52 weeks to assess FIX activity and bleeding rates and will be monitored for five years to evaluate the safety of AMT-061.
AMT-061 received FDA’s Breakthrough Therapy Designation and EMA’s access to the Priority Medicine regulatory initiative.
Following the news, shares in uniQure rose 6.7% in premarket trading.
Source: uniQure Announces Updated Clinical Data from Phase IIb Study of AMT-061 in Patients with Hemophilia B; Press Release