uniQure Announces Publication in the Journal Blood of Clinical Data from Phase I/II Trial of AMT-060 In Patients with Severe Hemophilia B
The published manuscript, entitled "Gene therapy with adeno-associated virus vector 5-human factor IX in adults with hemophilia B," shows that AAV5 liver-directed wildtype hFIX gene transfer was well tolerated and clinically effective in patients with severe and moderate-severe hemophilia B. No cellular immune responses to the AAV5 vector were detected and Factor IX (FIX) expression levels were stable over the entire observation period. The manuscript is available online today and will be included in a future print edition of Blood.
The study included ten adults with hemophilia B and severe-bleeding phenotype. A single infusion of AMT-060 had a favorable safety profile and resulted in stable and clinically-important FIX activity increases, along with a marked reduction in spontaneous bleeds and FIX concentrate use, without detectable cellular-immune responses against capsids. In the higher-dose cohort, mean FIX activity increased to 6.9% of normal. Annualized FIX use decreased by 73%, and mean annual bleeding rate declined by 70%, from 3.0 to 0.9. FIX activity was stable in both cohorts and eight of nine participants receiving FIX at study entry stopped prophylaxis.
"Blood's publication of this manuscript is a testament to the quality of the study and its significance to the advancement of gene therapy in hemophilia," stated Professor Wolfgang Miesbach, M.D., of the University Hospital Frankfurt, Germany. "We're very pleased to have these data published in a journal as highly regarded as Blood."
Additional follow-up on the patients from this study was presented on December 11, 2017, at the American Society of Hematology (ASH) Annual Meeting. The AAV5-based AMT-060 remains safe and well-tolerated with now up to two years of follow-up in the low-dose cohort and 1.5 years in the higher-dose cohort. There were no new serious adverse events and no development of inhibitors. To date, no patient in the study has had any loss of Factor IX activity or encountered a capsid-specific, T-cell-mediated immune response.
uniQure is preparing to initiate a pivotal study in 2018 with AMT-061, which combines an AAV5 vector with the FIX-Padua mutant. AMT-061 and AMT-060 are identical in structure apart from two nucleotide substitutions in the coding sequence for FIX. The gene variant, referred to as FIX-Padua, has been reported in multiple preclinical and nonclinical studies to provide an approximate 8 to 9-fold increase in FIX clotting activity compared to the wild-type FIX gene. 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.
"The data from the Phase I/II trial show that our AAV5-based gene therapies offer multi-year durability and a favorable immunogenicity profile, enabling hemophilia B patients to discontinue frequent infusions of FIX replacement therapy and to reduce the risk of spontaneous bleeding," stated Dr. Steven Zelenkofske, chief medical officer of uniQure. "With AAV5 emerging as a potential best-in-class vector for systemic administration to the liver, we look forward to advancing AAV5-FIX-Padua (AMT-061) into a pivotal trial in 2018."
uniQure is delivering on the promise of gene therapy - single treatments with potentially curative results. We are leveraging our modular and validated technology platform to rapidly advance a pipeline of proprietary and partnered gene therapies to treat patients with hemophilia, Huntington's disease and cardiovascular diseases. www.uniQure.com
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Maria E. Cantor
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