One of the biggest difficulties of bringing new therapeutic methods into clinical practice is targeted delivery. A recent study 1 shows the potential of using a gel for topical gene therapy.
Recessive dystrophic epidermolysis bullosa is a genetic disease that affects proper skin formation. The affected people have an extremely fragile skin, which often suffers from painful wounds and blisters. The disease is caused by a mutation in a collagen gene, COL7A1, which codes for collagen VII, a protein necessary for collagen stabilization. As collagen is an intrinsic component of skin cells, and responsible for their strength and elasticity (that is why most anti-aging skin products always include it among its components), this mutation affects the integrity of the skin allowing for easy “breaks”: wounds.
The authors of this study used gene therapy to introduce a working copy of the mutated gene, COL7A1, via a herpes simplex virus type-1 (HSV1) vector. Using de-activated viral vectors incapable of replicating inside the host is a common method for delivery of gene therapy into the cell nucleus and correct the mutation responsible for the disease.
After successful results in vitro and in model animals, the team started a Phase III trial on 31 patients (both adults and children), where they delivered the gene therapy in gel form in what is, so far, the first time that topical gene therapy has been used clinically.
This was a placebo-controlled trial in which one wound was treated with the gene therapy gel and another with placebo once a week until the wounds healed. The results of the study showed a significant improvement on wound healing of the topical gene therapy. At 12 weeks, 71% of the wounds receiving the “healing” gel had healed, compared to only 20% of those receiving placebo. In addition, neither relevant immune activation in response to the gel nor side effects were reported after application of the gel.
Both researchers and patients are very happy and optimistic about the results of the trial and intend to apply for FDA (Federal Drug Administration) approval in the next months.