Manipulating a patient’s DNA to effectively treat disease has now become a reality. In 2017, we saw the first gene editing therapies approved by the FDA (i.e. CAR-T cell therapies for cancer and adenovirus-vector based gene therapy for retinal dystrophy). Clinical trials have demonstrated efficacy in treating patients with sickle-cell disease and hemophilia. Additionally, gene therapy is being investigated in hundreds of preclinical studies including type 2 diabetes, obesity, multiple sclerosis and Parkinson’s disease. Given the vast pipeline, Massachusetts Institute of Technology researchers estimate approximately 40 gene therapies will be approved in the US by 2022.
Gene therapy aims to cure diseases by correcting the underlying genetic cause. The mechanism of action differs depending on the pathophysiology of disease. Generally, engineered genes are introduced to replace inactive, missing or malfunctioning genes, or lead to the death of specific cells (e.g. cancer cells). Viral vectors are typically used to introduce genes into cells, either in vivo or in vitro (in this case, modified cells are then infused back into the patient).
The FDA has recognized the benefit of gene therapy and recently published guidance documents aimed at fostering developments in the field. It will be interesting to see whether Health Canada adopts a similar approach and how these novel therapies come to life in the Canadian market.