Vascular Delivery of alpha-Sarcoglycan for LGMD2D

描述（由申请人提供）：最近完成了一项LGMD 2D肌内基因治疗试验，以替代由肌肉肌酸激酶启动子控制的rAAV 1递送的人α-肌聚糖基因（hSGCA）。观察基因表达长达6个月。未发生不良反应。这项研究为推进血管输送试验提供了基础和动力。在实验室中，我们已经确定rAAV.rh.74可以通过非人灵长类动物的股动脉有效地将hSGCA递送到特定的肌肉群。通过在输注部位近端使用临时结扎线和在膝盖处使用血压袖带将肢体与体循环隔离来实现输送。遏制病毒以提高安全性是肌肉萎缩症中首次血管基因递送试验的重要考虑因素。该方法安全、有效、重现性好。我们已经将这些发现提交给了FDA（IND前会议），他们接受了这种方法。此外，我们还获得了目前正在进行的毒理学-生物分布研究的资金（MDA），该研究将导致IND，允许进入临床试验。我们的中心拥有两个肌营养不良基因治疗的IND，我们有一个专门的工作人员，是自给自足的，能够准备所有必要的监管文件（IND，RAC，IRB）的临床试验。目前的赠款提案分为两个目标。Aim 1是临床试验用载体（自身互补rAAV.rh.74.tMCK.hSGCA）的制备。全国儿童医院具有及时制造载体的独特优势，因为儿童医院研究所的基因治疗中心已经建立了载体制造设施。临床级载体的生产可以在收到本赠款提案授予的资金后立即开始。目的2要求在LGMD 2D患者中进行剂量递增试验。NCH的基因治疗中心在基因治疗试验方面具有高素质和独特的经验。所提出的研究将是通过股动脉递送的rAAV.rh.74.tMCK.hSGCA的剂量递增试验。针对股四头肌肌肉将提供一种手段，提高肌肉力量，从而延长amperion。两条肢体将在一次治疗中进行灌注，这是FDA在我们的IND前会议上批准的方法。3名患者将接受低剂量载体（6 × 1011 vg/kg），另外3名患者将接受高剂量（2 × 1012 vg/kg）。对病毒和转基因的免疫应答将像我们在先前的基因治疗研究中所做的那样进行充分研究。在我们的临床试验项目中被证明是令人满意的并被广泛使用的结局指标将决定这种方法的有效性。

DESCRIPTION (provided by applicant): An intramuscular gene therapy trial in LGMD2D to replace the human alpha-sarcoglycan gene (hSGCA) delivered by rAAV1 under control of a muscle creatine kinase promoter was recently completed. Gene expression was observed for as long as 6 months. No adverse effects were encountered. That study provided the foundation and the impetus to move forward with a vascular delivery trial. In the laboratory we have established that rAAV.rh.74 can effectively deliver hSGCA to specific muscle groups through the femoral artery in the non-human primate. Delivery is achieved with the extremity isolated from the systemic circulation using a temporary ligature proximal to the site of infusion and a blood pressure cuff at the knee. Containment of virus to promote safety is an important consideration for the first vascular gene delivery trial in muscular dystrophy. The method is safe, effective and reproducible. We have presented these findings to the FDA (pre- IND meeting) and they were receptive to this approach. In addition we have obtained funding (MDA) for the toxicology-biodistribution study that is currently underway that will lead to an IND, permitting entrie to the clinical trial. Our Center holds two INDs for muscular dystrophy gene therapy and we have a devoted staff that is self sufficient and capable of preparing all of the necessary regulatory documents (IND, RAC, IRB) for the clinical trial. The current grant proposal is divided into two aims. Aim1 is the preparation of vector for the clinical trial (self-complementary rAAV.rh.74.tMCK.hSGCA). Nationwide Children's Hospital is uniquely positioned to make vector in a timely manner because a vector manufacturing facility has been established in the Center for Gene Therapy within the Children's Hospital Research Institute. Production of clinical grade vector can start immediately upon receiving funds awarded by this grant proposal. Aim 2 calls for the performance of a dose-escalation trial in LGMD2D patients. The Center for Gene Therapy at NCH is highly qualified and uniquely experienced in gene therapy trials. The proposed study will be a dose escalation trial of rAAV.rh.74.tMCK.hSGCA delivered through the femoral artery. Targeting the quadriceps muscle will provide a means for improving muscle strength and thereby prolong ambulation. Both limbs will be perfused within a single treatment episode, an approach approved by the FDA in our pre-IND meeting. Three patients will receive low dose vector (6x1011 vg/kg) and three others will receive the high dose (2x1012 vg/kg). The immune response to virus and transgene will be fully studied as we have done in prior gene therapy studies. The outcome measures proven to be satisfactory and used extensively in our clinical trials program will determine efficacy of this approach.