Long-Term AAV-Mediated Factor VIII Expression in Nine Hemophilia A Dogs: A 10 Year Follow-up Analysis on Durability, Safety and Vector Integration

作者：Giang N. Nguyen, J.K. Everett, Hayley E. Raymond, Samita Kafle, Elizabeth P. Merricks, Haig H. Kazazian, Timothy C. Nichols, Frederic D. Bushman, Denise E. Sabatino · 发表于：Blood · 年份：2019 · DOI：10.1182/blood-2019-126007 · 被引用次数：27 · 研究领域：Hemophilia Treatment and Research、Virus-based gene therapy research、Cancer-related gene regulation

Hemophilia is an X-linked bleeding disorder caused by a deficiency in clotting factor VIII (FVIII)(hemophilia A, HA) or factor IX (FIX)(hemophilia B, HB). While early clinical trials of AAV delivery of FIX for HB have demonstrated stable FIX expression for >8 years, an ongoing clinical trial of AAV-FVIII delivery for HA achieved high levels of transgene expression that unexpectedly declined after 1 year. Here we describe preclinical studies of AAV-canine FVIII (cFVIII) delivery in nine HA dogs with sustained FVIII expression for the duration of the study, as long as 10 years. FVIII was delivered using two delivery approaches: (1) co-administration of two AAV vectors encoding separate cFVIII heavy and light chains driven by the thyroxine binding globulin (TBG) promoter (Two chain approach)(TC) (n=5) at two AAV doses (2.5 x 1013vg/kg; F24, Woodstock, J60) and (1.2 x 1013vg/kg; Linus, H19) or (2) delivery of cFVIII as a single chain driven by the human alpha-1 anti-trypsin (hAAT) promoter (Single chain approach)(SC)(n=4) at two AAV doses (4 x 1013 vg/kg; M50, M06) and (2 x 1013vg/kg; M66, L51) (Sabatino 2011). We demonstrated that both strategies were efficacious; preventing >95% of spontaneous bleeding episodes without toxicity. We now report the long-term follow-up of between 2.2 and 10.1 years for these treated dogs. Dose-dependent cFVIII:C (Coatest SP4 FVIII) was observed. At the final time point, the cFVIII:C was 2.7% (F24), 7.1% (Woodstock), 4.5% (J60), 11.3%...