Diverse Strategies to Correct the Dystrophin Gene Using Vascular Delivery (U54)

描述(申请人提供)：目前，原则证明研究已经证实，基因替代疗法是治疗Duchenne肌营养不良症(DMD)的一种有前途的方法。我们通过肌肉注射rAAV-mini-dystrophin基因对这种疾病进行了临床I期安全基因治疗试验。整个领域都承认，血管输送，到达许多肌肉群，是我们改善患者功能的最大希望。在与FDA为U54做准备的初步讨论中，考虑到潜在的安全问题，我们被鼓励通过循环进行基因传递。我们目前的项目考虑到了这些因素。我们在初步研究中发现，rAAVS可以有效地将微肌营养不良蛋白输送到mdx小鼠的肌肉中。此外，我们有数据预测，这种AAV血清型可以通过将转基因传递给大型动物物种而跨越物种界限。这为我们目前的提议奠定了基础，整合了血管输送的安全性和有效性问题。我们计划将其引入IND并进行血管交付的I期安全性试验：该项目(AIM1)的第一个目标是确定我们设计的微营养不良蛋白转基因(基于文献中的最佳信息)可以从功能上改善营养不良肌肉。对于我们目前的IND，我们在MDX小鼠身上使用了一块分离的肌肉来证明功能有效性，我们将在这个提案中遵循这个例子。对于我们的第二个目标(目标2)，我们将把rAAV.microdystrophin传递给恒河猴。关于AAV及其携带的货物的免疫原性提出了许多问题。恒河猴允许我们在一个接近模拟临床试验的环境中解决所有这些问题。眼下有两个问题，一是病毒的安全传递，以实现转导；二是患者的安全，避免病毒的不良传播。因此，我们将通过放置在股动脉的球囊导管来传递我们的病毒构建。我们还将使用一些对AAV已有免疫力的猴子和其他对病毒具有NATve免疫力的猴子来测试免疫抑制方案在基因传递方面的适当性。在最终的目标3中，我们将根据我们与FDA的讨论进行毒理学/生物分布研究。从这个项目中获得的信息将允许我们提交一份用于DMD Boys的I期安全试验的IND。

Description (provided by applicant): Currently, proof-of-principle studies have established that gene replacement therapy represents a promising means of treatment for Duchenne muscular dystrophy (DMD). We have moved forward in a clinical phase I safety gene therapy trial for this disease by intramuscular delivery of an rAAV mini-dystrophin gene. It is acknowledged throughout the field that vascular delivery, reaching many muscle groups, is our best hope for improving patient function. In preliminary discussions with the FDA in preparation for this U54, we were encouraged to move forward with gene delivery through the circulation, being mindful of potential safety concerns. Our current project takes these considerations into account. We have found in preliminary studies that rAAVS can deliver micro-dystrophin efficiently to muscle in the mdx mouse. Further, we have data that predicts that this AAV serotype can cross species lines with delivery of a transgene to a large animal species. This sets the stage for our current proposal, integrating safety and efficacy concerns of vascular delivery. Our plan to bring this to IND and a phase I safety trial for vascular delivery is as follows: The first goal for this project (AIM1) is to establish that the micro-dystrophin transgene that we designed (based on the best information from the literature) can functionally improve dystrophic muscle. For our current IND we used an isolated muscle in the mdx mouse to prove functional efficacy and we will follow this example in this proposal. For our second goal (AIM 2) we will deliver the rAAVS.micro-dystrophin to the rhesus macaque. There have been many issues raised regarding the immunogenicity of both AAV and the cargo it carries. The rhesus macaque permits us to address all of these issues in an environment that closely simulates a clinical trial. Two concerns are at hand, safe passage of virus to achieve transduction and safety to the patient avoiding undesirable spread of virus. Thus, we will deliver our viral construct through a balloon catheter placed in the femoral artery. We will also test appropriateness of immunosuppression regimens for gene delivery using some monkeys with pre-existing immunity to AAV and others naTve to the virus. In the final AIM 3, we will do the toxicology/biodistribution studies in accordance with our discussions with FDA. The information derived from this project will permit us to submit an IND for a phase I safety trial in DMD boys.