Advancements in AAV-mediated Gene Therapy for Pompe Disease

Abstract

Pompe disease (glycogen storage disease type II) is caused by mutations in acid α-glucosidase (GAA) resulting in lysosomal pathology and impairment of the muscular and cardio-pulmonary systems. Enzyme replacement therapy (ERT), the only approved therapy for Pompe disease, improves muscle function by reducing glycogen accumulation but this approach entails several limitations including a short drug half-life and an antibody response that results in reduced efficacy. To address these limitations, new treatments such as gene therapy are under development to increase the intrinsic ability of the affected cells to produce GAA. Key components to gene therapy strategies include the choice of vector, promoter, and the route of administration. The efficacy of gene therapy depends on the ability of the vector to drive gene expression in the target tissue and also on the recipient's immune tolerance to the transgene protein. In this review, we discuss the preclinical and clinical studies that are paving the way for the development of a gene therapy strategy for patients with early and late onset Pompe disease as well as some of the challenges for advancing gene therapy.

Keywords: Pompe disease; adeno-associated virus (AAV); autophagy; immune-response; intramuscular; intrathecal; intravenous; lysosomes; manufacturing; promoter.

Fig.1

PAS-stained sections (shown in black and white) of gastrocnemius muscle from a 7-month-old GAA^-/- mouse after 4 ERT injections. Arrows indicate “holes” in the core of muscle fibers.