Introduction to Gene Therapy

Many diseases such as cystic fibrosis, muscular dystrophy, haemophilia and cancer are caused by faulty genes. Gene therapy involves the addition of a healthy, working copy of the gene into appropriate cells in the body to replace or override the faulty copy present in the genome. Unlike most conventional medicines, instead of treating the symptoms of a disease, gene therapy has the potential to correct the underlying cause.



Why use Gene Therapy to Treat CF?

CF is a good candidate for gene therapy as it is primarily caused by mutations in a single gene. A normal copy of the gene could be delivered to patients via topical delivery to the lung, not requiring invasive techniques or surgery. A gene complementation approach would also directly target the cause of the disease and could correct many aspects of the complex lung pathology.



Other CF Gene Therapy Groups

The UKCFGTC are not the only organisation researching the use of gene therapy for Cystic Fibrosis. We have close contacts and interactions with a number of other groups who are making advances in the field.



Successful Applications of Gene Therapy

Over 1600 clinical trials have been conducted using gene therapy approaches. The Journal of Gene Medicine maintains an excellent publicly accessable database of all such studies. Despite the number of trials, progress into actual clinical products has been slow. However, increasingly more and more clinical trials are reaching phase III and have a good chance of becoming licensed products for a range of diseases.



CF Gene Therapy Clinical Trials

CF gene therapy approaches have been based on the assumption that the target cell population is the respiratory epithelial cells lining the lung, although the majority of clinical trials have used delivery of the GTA to the nasal and maxillary sinus epithelia of CF patient volunteers as a surrogate tissue. In total, there have been 25 published clinical trials for CF and non-viral approaches have accounted for nine of these (Griesenbach & Alton 2009).




A frozen vial of GL67A (left) and a frozen vial of pGM169 plasmid DNA (right)


Sheep lung parenchyma (cell nuclei blue) transduced with an adenoviral vector (green).


Pellets of DNA following precipitation.