uniQure is advancing a promising clinical program focused on hemophilia B, a severe orphan blood clotting disorder. Our gene therapy product candidate AMT-061 consists of an AAV5 viral vector carrying a gene cassette with the Padua variant of Factor IX (FIX-Padua). uniQure is now enrolling patients in the Phase III HOPE-B pivotal study of AMT-061 for the treatment of patients with severe and moderately severe hemophilia B (view press release).
Our goal in hemophilia B is to develop the safest and most effective gene therapy with the broadest application to patients. We believe AMT-061 may be the first gene therapy to provide durable, curative benefits to nearly all patients with hemophilia B, with optimized clinical and safety benefits (view press release).
AMT-061 and AMT-060, the latter of which has been tested in 10 patients in an ongoing Phase I/II study, are identical gene therapies apart from two nucleotide substitutions in the coding sequence for FIX. The gene variant, referred to as FIX-Padua, has been reported to provide an approximate 8 to 9-fold increase in FIX activity compared to the wild-type FIX protein used in AMT-060. All other critical quality attributes of AMT-061 are expected to be comparable to those of AMT-060, as AMT-061 utilizes the same AAV5 capsid and proprietary insect cell-based manufacturing platform.
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.
uniQure’s AAV5-based gene therapies have been demonstrated to be generally safe and well-tolerated in three uniQure trials conducted in 22 patients in hemophilia B and other indications. In contrast to data reported using other AAV capsids, no patient treated in clinical trials with our AAV5 gene therapies has experienced any T-cell-mediated immune response to the capsid.
Additionally, our hemophilia B gene therapy has demonstrated a very low screening failure rate, providing the opportunity for all, or nearly all, hemophilia B patients to be eligible for gene transfer with AMT-061. We also have presented clinical data demonstrating that the presence of pre-existing anti-AAV5 neutralizing antibodies does not predict the potential efficacy of AAV5-mediated gene transfer in patients with hemophilia B (view press release). We believe these factors contribute to making AAV5 a potential best-in-class vector for delivering gene therapies more effectively and safely to a greater portion of patients in need of treatment.
These factors, along with our commercial-scale manufacturing capabilities, differentiate AMT-061 from other hemophilia gene therapies in development. In addition to advancing our Phase III pivotal trial, we have also initiated patient recruitment for our Phase IIb dose-confirmation study and expect to commence enrollment in July. We look forward to announcing top-line FIX data from the dose-confirmation study before the end of the year.
The Company is in pre-clinical evaluation for a gene therapy to treat hemophilia A.