Niemeyer Glenn P, Herzog Roland W, Mount Jane, Arruda Valder R, Tillson D Michael, Hathcock John, van Ginkel Frederik W, High Katherine A, Lothrop Clinton D
Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, AL, USA.
Blood. 2009 Jan 22;113(4):797-806. doi: 10.1182/blood-2008-10-181479. Epub 2008 Oct 28.
Preclinical studies and initial clinical trials have documented the feasibility of adenoassociated virus (AAV)-mediated gene therapy for hemophilia B. In an 8-year study, inhibitor-prone hemophilia B dogs (n = 2) treated with liver-directed AAV2 factor IX (FIX) gene therapy did not have a single bleed requiring FIX replacement, whereas dogs undergoing muscle-directed gene therapy (n = 3) had a bleed frequency similar to untreated FIX-deficient dogs. Coagulation tests (whole blood clotting time [WBCT], activated clotting time [ACT], and activated partial thromboplastin time [aPTT]) have remained at the upper limits of the normal ranges in the 2 dogs that received liver-directed gene therapy. The FIX activity has remained stable between 4% and 10% in both liver-treated dogs, but is undetectable in the dogs undergoing muscle-directed gene transfer. Integration site analysis by linear amplification-mediated polymerase chain reaction (LAM-PCR) suggested the vector sequences have persisted predominantly in extrachromosomal form. Complete blood count (CBC), serum chemistries, bile acid profile, hepatic magnetic resonance imaging (MRI) and computed tomography (CT) scans, and liver biopsy were normal with no evidence for tumor formation. AAV-mediated liver-directed gene therapy corrected the hemophilia phenotype without toxicity or inhibitor development in the inhibitor-prone null mutation dogs for more than 8 years.
临床前研究和初步临床试验已证明腺相关病毒（AAV）介导的B型血友病基因治疗的可行性。在一项为期8年的研究中，接受肝脏定向AAV2因子IX（FIX）基因治疗的易产生抑制剂的B型血友病犬（n = 2）没有一次出血需要FIX替代治疗，而接受肌肉定向基因治疗的犬（n = 3）的出血频率与未治疗的FIX缺乏犬相似。在接受肝脏定向基因治疗的2只犬中，凝血试验（全血凝固时间[WBCT]、活化凝血时间[ACT]和活化部分凝血活酶时间[aPTT]）一直保持在正常范围的上限。在两只接受肝脏治疗的犬中，FIX活性在4%至10%之间保持稳定，但在接受肌肉定向基因转移的犬中检测不到。通过线性扩增介导的聚合酶链反应（LAM-PCR）进行的整合位点分析表明，载体序列主要以染色体外形式存在。全血细胞计数（CBC）、血清化学、胆汁酸谱、肝脏磁共振成像（MRI）和计算机断层扫描（CT）扫描以及肝脏活检均正常，没有肿瘤形成的证据。AAV介导的肝脏定向基因治疗在易产生抑制剂的无效突变犬中纠正了血友病表型，且在超过8年的时间里没有毒性或抑制剂产生。
