Safety, efficacy, and availability of genetic therapies to treat neuromuscular disorders

Genetic mutation underlies the etiology of many debilitating neuromuscular disorders. Diseases such as spinal muscular atrophy and Duchenne muscular dystrophy have profound impact on quality of life, and often begin to manifest in infancy or childhood. Identification of the causative genetic mutations for diseases such as spinal muscular atrophy and Duchenne muscular dystrophy provides opportunities for the development of targeted genetic therapies that aim to correct protein deficiencies resulting from these mutations. Clinical trials have demonstrated some efficacy, but only in small studies. Purpose: The primary objective of this review was to determine the safety, efficacy, and availability of gene therapy treatments for neuromuscular diseases compared to standard of care or placebo. The secondary objective was to review clinical trials that are in progress to evaluate therapies currently in development. Methods: A systematic review was performed using databases Pubmed, Medline, Cochrane, and ClinicalTrials.gov. The search terms "gene therapy" and "neurological or muscular" were utilized. The search results from ClincalTrials.gov were limited to completed trials. Results: Published trials detail the utilization of several treatment modalities, including single gene replacement via vector-mediated delivery, transfection and infusion of autologous stem cells, and modification of protein translation by exon skipping. Conclusions: Many treatments demonstrate promise in slowing the progression of disease and exhibit mild side effect profiles. Larger studies are needed to ascertain superiority over standard of care procedures, but favorable tolerability potentially justifies expansion of clinical trials to larger cohorts.