uniQure Announces Achievement of Planned Enrollment in HOPE-B Pivotal Trial of AMT-061 (Etranacogene Dezaparvovec) in Patients with Hemophilia B

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uniQure N.V. (NASDAQ: QURE), a leading gene therapy company advancing transformative therapies for patients with severe unmet medical needs, today announced that the planned enrollment of 56 patients has been achieved in the HOPE-B pivotal trial of etranacogene dezaparvovec (AMT-061), an investigational AAV5-based gene therapy incorporating the patent-protected FIX-Padua variant for the treatment of patients with severe and moderately severe hemophilia B. Due to the high level of interest in the study from both patients and study investigators, uniQure expects to over-enroll up to six additional patients before the end of September. Etranacogene dezaparvovec has been granted Breakthrough Therapy Designation by the United States Food and Drug Administration and access to Priority Medicines (PRIME) regulatory initiative by the European Medicines Agency.

“We are extremely pleased to reach this important milestone in our ongoing development of etranacogene dezaparvovec, which we believe has the potential to be the first and best-in-class gene therapy for patients with hemophilia B,” stated Matt Kapusta, chief executive officer of uniQure. “We appreciate the tremendous support from the hemophilia patient community in achieving this important goal ahead of schedule and look forward to sharing top-line data from the Phase III trial, which we expect to do next year.”

The pivotal Phase III HOPE-B study builds on the success of the interim 36-week results of the Company’s ongoing Phase IIb study of etranacogene dezaparvovec, which demonstrated that a single administration of the investigational gene therapy resulted in sustained increases in Factor IX (FIX) levels up to 54% of normal, and a mean FIX level of 45% of normal. During that time, no patient reported any bleeding events or required any infusion of FIX replacement therapy for bleeds or experienced any material loss of FIX activity. Additionally, an ongoing Phase I/II study of AMT-060, the Company’s first-generation gene therapy for the treatment of hemophilia B, demonstrated that all 10 patients continue to show sustained and stable increases in FIX activity and long-term clinical benefits at up to 3.5 years of observation.

“We are very excited and proud to have achieved the targeted patient enrollment in the HOPE-B study in just a little more than one year from study initiation,” added Robert Gut, M.D., Ph.D., chief medical officer at uniQure. “This multi-center, multinational trial involves 39 clinical sites across 9 countries, and highlights the outstanding effort and passion of our clinical operations, clinical development, medical affairs and project management teams. We would like to thank all study participants, advisors, primary investigators and the whole study staff in the United States and Europe for their great contribution and support.”

About the Pivotal Phase III HOPE-B Study
The pivotal Phase III HOPE-B trial is a multinational, open-label, single-arm study to evaluate the safety and efficacy of etranacogene dezaparvovec. Adult hemophilia B patients classified as severe or moderately severe are 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 receivea single intravenous administration of etranacogene dezaparvovec at the 2x1013 gc/kg dose. Dosing of patients in the HOPE-B pivotal trial was initiated in January 2019.

The study’s primary endpoint is the assessment of Factor IX activity 26 weeks after dosing. Secondary endpoints include annualized bleeding rate (ABR) and usage of Factor IX replacement therapy over a 52-week time frame, as well as other efficacy and safety aspects. Post-treatment, patients will be followed for 5 years.

Patients enrolled in the HOPE-B pivotal trial will be tested for the presence of pre-existing neutralizing antibodies to AAV5 but will not be excluded from the trial based on their titers. Previous studies performed by uniQure suggest that AAV5-based gene therapies may be viable treatments for at least 97% of patients.

About Etranacogene Dezaparvovec (AMT-061)
Etranacogene dezaparvovec, also known as AMT-061, consists of an AAV5 viral vector carrying a gene cassette with the patent-protected Padua variant of Factor IX (FIX-Padua). AAV5-based gene therapies have been demonstrated to be safe and well tolerated in many clinical trials, including four uniQure trials conducted in 25 patients in hemophilia B and other indications. No patient treated in clinical trials with the Company’s AAV5-based gene therapies has experienced any cytotoxic T-cell-mediated immune response to the capsid. Additionally, preclinical and clinical data show that AAV5-based gene therapies may be clinically effective in patients with pre-existing antibodies to AAV5, thereby potentially increasing patient eligibility for treatment compared to other gene therapy product candidates.