The goal of gene therapy for DMD is to slow or stabilize muscle degeneration by delivering a gene encoding a functional mini-dystrophin (or micro-dystrophin) to muscle cells.1,5
Gene therapy aims to add a single gene, making it a potential modality for DMD—a disease caused by a mutation of a single gene.1,2,6
Studies with dystrophin-deficient animal models supported further clinical investigation into AAV gene therapy. In small mammals, systemic administration of AAV-micro-dystrophin preserved muscle function for at least 1 year by demonstrating a uniform, body-wide expression of dystrophin.1,7-9
Animal study data are not indicative of results in human clinical trials and are used only to measure the benefits and risks of further clinical investigation. However, preliminary results in animals support the investigation of gene therapy in DMD in clinical trials.1,7-9
Research is ongoing to understand Pfizer’s investigational gene therapy for DMD, including safety considerations, immune response, efficacy, durability, and post-treatment considerations.1-3,10,11
If Pfizer's gene therapy for DMD is FDA approved, patients will be monitored in the short and long term following treatment.
Description: The removal or correction of pieces of DNA within the genome.12
Status: Clinical trials are ongoing.1,13
FDA approval: Not FDA approved to treat DMD.1
Description: The delivery of a gene into target cells using a vector to produce a functional protein.4,12
Status: Clinical trials are ongoing.1
FDA approval: Accelerated approval of one treatment option.14
Exon skippers
Description: The restoration of the reading frame of the gene, leading to translation of a shortened but functional protein. Exon skippers are antisense oligonucleotides that bind to target exons during pre-mRNA splicing to influence the splicing machinery to skip a specific exon from the mature mRNA transcript.1,6
Status: Clinical trials are ongoing.1
FDA approval: Some exon skipping therapies are FDA approved to treat specific mutations of the DMD gene, and others are in ongoing clinical trials.2
Nonsense mutation read-through
Description: The suppression of premature stop codons. The subsequent read-through may lead to some protein production. Nonsense mutations are found in approximately 10%-15% of patients with DMD.1,2
Status: Clinical trials are ongoing.2
FDA approval: Not FDA approved to treat DMD.2