Vascular Delivery of alpha-Sarcoglycan for LGMD2D

描述（由申请人提供）：最近完成了一项LGMD2D肌肉内基因治疗试验，以取代由rAAV1在肌肉肌酸激酶启动子控制下传递的人α -肌聚糖基因（hSGCA）。基因表达观察时间长达6个月。没有遇到任何不良反应。这项研究为推进血管输送试验提供了基础和动力。在实验室里我们已经确定raav。rh。74可以有效地将hSGCA通过股动脉输送到非人类灵长类动物的特定肌肉群。通过在输液部位近端使用临时结扎和在膝关节处使用血压袖带将四肢与体循环隔离，从而实现给药。遏制病毒以提高安全性是肌萎缩症患者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FDA （pre- IND会议），他们接受了这种方法。此外，我们已经为目前正在进行的毒理学-生物分布研究获得了资金（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萎缩症基因治疗的IND，我们有一个专门的工作人员，是自给自足的，有能力准备所有必要的临床试验的监管文件（IND， RAC， IRB）。目前的拨款提案分为两个目标。Aim1为临床试验载体的制备（自互补rAAV.rh.74.tMCK.hSGCA）。全国儿童医院在及时制造载体方面具有独特的优势，因为在儿童医院研究所的基因治疗中心建立了载体制造设施。临床级载体的生产可在收到本拨款提案所授予的资金后立即开始。目标2要求在LGMD2D患者中进行剂量递增试验。NCH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。拟议的研究将是rAAV.rh.74.tMCK的剂量递增试验。hSGCA通过股动脉输送。针对股四头肌将提供一种手段，提高肌肉力量，从而延长行走。两肢将在一次治疗中灌注，这是FDA在我们的ind前会议上批准的一种方法。3名患者接受低剂量载体（6 × 1011 vg/kg），另外3名患者接受高剂量载体（2 × 1012 vg/kg）。我们将充分研究对病毒和转基因的免疫反应，正如我们在先前的基因治疗研究中所做的那样。结果测量被证明是令人满意的，并在我们的临床试验项目中广泛使用，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.