腺相关病毒 1 型（rAAV1）α-1 抗胰蛋白酶载体在非人灵长类动物中的肢体灌注递送是安全的，但不足以用于治疗。

Limb Perfusion Delivery of a rAAV1 Alpha-1 Antitrypsin Vector in Non-Human Primates Is Safe but Insufficient for Therapy.

机构信息

Horae Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.

Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.

出版信息

Genes (Basel). 2024 Sep 10;15(9):1188. doi: 10.3390/genes15091188.

DOI:10.3390/genes15091188

PMID:39336779

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11431094/

Abstract

BACKGROUND/OBJECTIVES: α-1 antitrypsin (AAT) deficiency is an inherited, genetic condition characterized by reduced serum levels of AAT and increased risk of developing emphysema and liver disease. AAT is normally synthesized primarily in the liver, but muscle-targeting with a recombinant adeno-associated virus (rAAV) vector for α-1 antitrypsin (AAT) gene therapy has been used to minimize liver exposure to the virus and hepatotoxicity. Clinical trials of direct intramuscular (IM) administration of rAAV1-hAAT have demonstrated its overall safety and transgene expression for 5 years. However, the failure to reach the therapeutic target level after 100 large-volume (1.5 mL) IM injections of maximally concentrated vector led us to pursue a muscle-targeting approach using isolated limb perfusion. This targets the rAAV to a greater muscle mass and allows for a higher total volume (and thereby a higher dose) than is tolerable by multiple direct IM injections. Limb perfusion has been shown to be feasible in non-human primates using the rAAV1 serotype and a ubiquitous promoter expressing an epitope-tagged AAT matched to the host species.

METHODS

In this study, we performed a biodistribution and preclinical safety study in non-human primates with a clinical candidate rAAV1-human AAT (hAAT) vector at doses ranging from 3.0 × 10 to 1.3 × 10 vg/kg, bracketing those used in our clinical trials.

RESULTS

We found that limb perfusion delivery of rAAV1-hAAT was safe and showed a biodistribution pattern similar to previous studies. However, serum levels of AAT obtained with high-dose limb perfusion still reached only ~50% of the target serum levels.

CONCLUSIONS

Our results suggest that clinically effective AAT gene therapy may ultimately require delivery at doses between 3.5 × 10-1 × 10 vg/kg, which is within the dose range used for approved rAAV gene therapies. Muscle-targeting strategies could be incorporated when delivering systemic administration of high-dose rAAV gene therapies to increase transduction of muscle tissues and reduce the burden on the liver, especially in diseases that can present with hepatotoxicity such as AAT deficiency.

摘要

背景/目的：α-1 抗胰蛋白酶（AAT）缺乏症是一种遗传性遗传疾病，其特征是血清 AAT 水平降低，肺气肿和肝病的风险增加。AAT 通常主要在肝脏中合成，但使用重组腺相关病毒（rAAV）载体对肌肉进行靶向治疗可用于最大限度地减少病毒和肝毒性对肝脏的暴露。直接肌肉内（IM）给予 rAAV1-hAAT 的临床试验已证明其整体安全性和转基因表达可维持 5 年。然而，在进行了 100 次大容量（1.5mL）最大浓度载体的 IM 注射后未能达到治疗目标水平，促使我们采用孤立肢体灌注的肌肉靶向方法。这使得 rAAV 能够靶向更大的肌肉质量，并允许使用比多次直接 IM 注射更耐受的更高总容量（从而更高剂量）。已经证明，在非人类灵长类动物中，使用 rAAV1 血清型和表达与宿主物种匹配的表位标记 AAT 的普遍启动子可以进行肢体灌注。

方法

在这项研究中，我们在非人类灵长类动物中进行了一项生物分布和临床前安全性研究，使用的临床候选 rAAV1-人 AAT（hAAT）载体剂量范围为 3.0×10 至 1.3×10 vg/kg，涵盖了我们临床试验中使用的剂量。

结果

我们发现 rAAV1-hAAT 的肢体灌注递送是安全的，并且显示出与先前研究相似的生物分布模式。然而，高剂量肢体灌注获得的 AAT 血清水平仅达到目标血清水平的~50%左右。

结论

我们的结果表明，有效的临床 AAT 基因治疗最终可能需要在 3.5×10-1×10 vg/kg 的剂量范围内进行，这在已批准的 rAAV 基因治疗的剂量范围内。在向全身给予高剂量 rAAV 基因治疗时，可以采用肌肉靶向策略来增加肌肉组织的转导，减少对肝脏的负担，特别是在可能出现肝毒性的疾病中，如 AAT 缺乏症。