Michel Michaelides

BACKGROUND: Mutations in RPE65 cause Leber's congenital amaurosis, a progressive retinal degenerative disease that severely impairs sight in children. Gene therapy can result in modest improvements in night vision, but knowledge of its efficacy in humans is limited. METHODS: We performed a phase 1-2 open-label trial involving 12 participants to evaluate the safety and efficacy of gene therapy with a recombinant adeno-associated virus 2/2 (rAAV2/2) vector carrying the RPE65 complementary DNA, and measured visual function over the course of 3 years. Four participants were administered a lower dose of the vector, and 8 were administered a higher dose. In a parallel study in dogs, we investigated the relationship among vector dose, visual function, and electroretinography (ERG) findings. RESULTS: Improvements in retinal sensitivity were evident, to varying extents, in six participants for up to 3 years, peaking at 6 to 12 months after treatment and then declining. No associated improvement in retinal function was detected by means of ERG. Three participants had intraocular inflammation, and two had clinically significant deterioration of visual acuity. The reduction in central retinal thickness varied among participants. In dogs, RPE65 gene therapy with the same vector at lower doses improved vision-guided behavior, but only higher doses resulted in improvements in retinal function that were detectable with the use of ERG. CONCLUSIONS: Gene therapy with rAAV2/2 RPE65 vector improved retinal sensitivity, albeit modestly and temporarily. Comparison with the results obtained in the dog model indicates that there is a species difference in the amount of RPE65 required to drive the visual cycle and that the demand for RPE65 in affected persons was not met to the extent required for a durable, robust effect. (Funded by the National Institute for Health Research and others; ClinicalTrials.gov number, NCT00643747.).

OBJECTIVES: To report on the causes of blindness certifications in England and Wales in working age adults (16-64 years) in 2009-2010; and to compare these with figures from 1999 to 2000. DESIGN: Analysis of the national database of blindness certificates of vision impairment (CVIs) received by the Certifications Office. SETTING AND PARTICIPANTS: Working age (16-64 years) population of England and Wales. MAIN OUTCOME MEASURES: Number and cause of blindness certifications. RESULTS: The Certifications Office received 1756 CVIs for blindness from persons aged between 16 and 64 inclusive between 1 April 2009 and 31 March 2010. The main causes of blindness certifications were hereditary retinal disorders (354 certifications comprising 20.2% of the total), diabetic retinopathy/maculopathy (253 persons, 14.4%) and optic atrophy (248 persons, 14.1%). Together, these three leading causes accounted for almost 50% of all blindness certifications. Between 1 April 1999 and 31 March 2000, the leading causes of blindness certification were diabetic retinopathy/maculopathy (17.7%), hereditary retinal disorders (15.8%) and optic atrophy (10.1%). CONCLUSIONS: For the first time in at least five decades, diabetic retinopathy/maculopathy is no longer the leading cause of certifiable blindness among working age adults in England and Wales, having been overtaken by inherited retinal disorders. This change may be related to factors including the introduction of nationwide diabetic retinopathy screening programmes in England and Wales and improved glycaemic control. Inherited retinal disease, now representing the commonest cause of certification in the working age population, has clinical and research implications, including with respect to the provision of care/resources in the NHS and the allocation of research funding.

OBJECTIVE: To report the 2-year outcomes of the BOLT study, a prospective randomized controlled trial evaluating intravitreous bevacizumab and modified Early Treatment Diabetic Retinopathy Study (ETDRS) macular laser therapy (MLT) in patients with persistent clinically significant macular edema (CSME). METHODS: In a 2-year, single-center, randomized controlled trial, 80 patients with center-involving CSME and visual acuity of 20/40 to 20/320 were randomized to receive either bevacizumab or MLT. MAIN OUTCOME MEASURES: PRIMARY OUTCOME: difference in ETDRS best-corrected visual acuity (BCVA) between arms. SECONDARY OUTCOMES: mean change in BCVA, proportion gaining at least 15 and at least 10 ETDRS letters, losing fewer than 15 and at least 30 letters, change in central macular thickness, ETDRS retinopathy severity, and safety outcomes. RESULTS: At 2 years, mean (SD) ETDRS BCVA was 64.4 (13.3) (ETDRS equivalent Snellen fraction: 20/50) in the bevacizumab arm and 54.8 (12.6) (20/80) in the MLT arm (P=.005). The bevacizumab arm gained a median of 9 ETDRS letters vs 2.5 letters for MLT (P=.005), with a mean gain of 8.6 letters for bevacizumab vs amean loss of 0.5 letters for MLT. Forty-nine percent of patients gained 10 or more letters (P=.001) and 32% gained at least 15 letters (P=.004) for bevacizumab vs 7% and 4% for MLT. Percentage who lost fewer than 15 letters in the MLT arm was 86% vs 100% for bevacizumab (P=.03). Mean reduction in central macular thickness was 146 μm in the bevacizumab arm vs 118 μm in the MLT arm. The median number of treatments over 24 months was 13 for bevacizumab and 4 for MLT. CONCLUSIONS: This study provides evidence supporting longer-term use of intravitreous bevacizumab for persistent center-involving CSME. APPLICATION TO CLINICAL PRACTICE: Improvements in BCVA and central macular thickness seen with bevacizumab at 1 year were maintained over the second year with a mean of 4 injections. TRIAL REGISTRATION: eudract.ema.europa.eu Identifier: 2007-000847-89