The drug development process
To develop a gene therapy treatment, scientists discover what gene(s) are missing, mutated or defective, and if corrected could cure disease. Next, researchers find the most effective delivery vehicle to carry and incorporate the new gene into the patient and to the target cells.
Before any gene therapy is used to treat humans, the therapy undergoes rigorous testing and must satisfy strict safety, quality, efficacy and ethical requirements.
During preclinical testing, the efficacy and the safety of the vector is initially tested on isolated human cells. Next, the vector is tested in live whole organisms. This is a necessary step to determine the efficacy and safety of the gene therapy in a whole organism, as it may differ from tests in isolated target cells.
During the clinical stage, treatments are incrementally tested on humans for safety and efficacy. The first objective is to confirm product safety; if there is a notable safety concern, the trial cannot progress. In addition to safety, efficacy parameters are evaluated. Trials will start with small samples sizes and low vector dosages, and increase incrementally if safety and efficacy are confirmed throughout.
To perform preclinical and clinical tasks and beyond into commercial, it is important to be able to manufacture large quantities of the gene therapy product. Living cells are used to grow the AAV vector, followed by purification steps to isolate the vector from the living production cells.
These steps are carried out under tight quality controls and in exceptionally clean facilities to ensure the purity and quality of the product. Finally, the AAV vector is formulated into a solution that makes it injectable and it is filled into sterile vials for storing.