Pivotal Advancement in Gene Therapy for Dominant RP
Genable, a Foundation-funded biotechnology company in Ireland, has used an innovative gene therapy to slow the progression of vision loss in mice affected by a dominant form of retinitis pigmentosa. The company is working toward a study of the treatment in larger animal models with the goal of launching a clinical trial thereafter.
Treating dominant forms of retinal degenerative disease with gene therapy is challenging, because the process requires two steps: 1) shutting down the defective gene and 2) delivering a new, healthy gene. Genable’s treatment employs RNA interference (RNAi) to shut down the disease-causing gene.
A benefit of RNAi is its effectiveness regardless of the variation in the unhealthy gene. In the mouse study, Genable’s RNAi technology shut down the gene rhodopsin, which can have more than 100 disease-causing variations.
An adeno-associated virus (AAV) was used to deliver both the suppressive and replacement components of the treatment. AAV is the same delivery technology currently being used in landmark clinical trials of gene therapy that are restoring vision in children and young adults with Leber congenital amaurosis.
“We are very encouraged by Genable’s progress,” says Steve Bramer, Ph.D., chief drug development officer with the Foundation’s clinical trial organization. “Their RNAi technology, its ability to suppress the unhealthy gene, overcomes a major hurdle in developing gene therapy for people with dominant forms of RP. Genable has made a big step forward.”
Results of Genable’s gene therapy study were presented at the XVIIIth Annual Congress of the European Society of Gene and Cell Therapy held October 22-25, 2010 in Milan, Italy.