This talk will cover the development and instigation of a clinical gene therapy trial for an inherited retinal disease; choroideremia. It will also outline some early results of the trial, which is currently ongoing.
Development of the gene therapy vector involved a range of in vitro and in vivo studies, from cell-based protein assays to electrophysiological testing in laboratory mice. Preclinical results showed AAV can successfully produce functional REP1 protein in patient fibroblasts. The vector shows targeting of retinal cells and has good safety and efficacy in animal models.

The trial itself is an open label dose escalation study, involving two groups treated with different doses of adeno-associated viral vector (AAV2) encoding Rab-escort Protein 1 (REP1). A range of clinical tests are used to assess the safety and efficacy of treatment. So far in the clinical trial, 6 patients have been treated with the low dose AAV.REP1 vector. Early results show good safety and some encouraging functional effects.

This is the first time gene therapy has been tested in people with normal visual acuity and may have implications for other inherited retinal diseases.