Gene therapy is an experimental technique that uses genes to treat or prevent disease. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery.

A number of gene therapies have now received marketing authorizations in the US and Europe. The first to have received approval from the US and Europe was Glybera, which was approved in Europe in 2012 by the EMA for lipoprotein lipase (LPL) deficiency. Although gene therapy is a promising treatment option for a number of diseases (including inherited disorders, some types of cancer, and certain viral infections), the technique remains risky and is still under study to make sure that it will be safe and effective.

The drug uses a viral vector that inserts the wild-type lipoprotein lipase (LPL)-encoding gene in patients for whom the gene is mutated, causing the protein it encodes to be non-functional. Alternately, a sample of the patient’s cells can be removed and exposed to the vector in a laboratory setting. The cells containing the vector are then returned to the patient. If the treatment is successful, the new gene delivered by the vector will make a functioning protein.

In subsequent years, more gene therapy products have been approved; this includes an oncolytic virus, a stem cell-based gene therapy, and, as of 2017, two chimeric antigen receptor (CAR)-T cell therapies. Researchers must overcome many technical challenges before gene therapy will be a practical approach to treating disease.

The current pipeline for gene therapies is very large, covering 985 active programs across all therapy areas. Although the majority (76%) are at either the Discovery or Preclinical stages and will not reach the market for a number of years, the general trend indicates that gene therapies will continue to grow in prominence. More approvals can be anticipated across various indications.