From UK a small phase 1/2 clinical trial based on retinal gene therapy in patients with choroideremia. This is a X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1). The multicentre clinical trial included just 6 patients which were administered adeno-associated viral (AAV) vector encoding REP1 (AAV.REP1). Aim of the study to test the treatment’s safety but not its effectiveness. The paper published on The Lancet, explains that two patients with advanced choroideremia who had low baseline best corrected visual acuity gained 21 letters and 11 letters (more than two and four lines of vision). Four other patients with near normal best corrected visual acuity at baseline recovered to within one to three letters. In all patients, over the 6 months, the increase in retinal sensitivity in the treated eyes was correlated with the vector dose administered per mm2 of surviving retina. The initial results of this retinal gene therapy trial are consistent with improved rod and cone function that overcome any negative effects of retinal detachment. These findings lend support to further assessment of gene therapy in the treatment of choroideremia and other diseases, such as age-related macular degeneration, for which intervention should ideally be applied before the onset of retinal thinning.