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From darkness to light: prospects for therapy for childhood retinal disease Anthony T Moore Moorfields Eye Hospital and Institute of Ophthalmology UCL Retinal dystrophies: pathways to therapy clinical phenotype gene mapping protein function animal models Human treatment trials UC Clinical trial of gene therapy for early-onset severeL retinal degeneration caused by defects in RPE65 JWB Bainbridge, AJ Smith, SS Barker, S Robbie, R Henderson, K Balaggan, A Viswanathan, GE Holder, A Stockman, N Tyler, S Petersen-Jones, SS Bhattacharya, AJ Thrasher, FW Fitzke, BJ Carter, GS Rubin, AT Moore, RR Ali and the Moorfields Eye Hospital and UCL Eye Gene Therapy Study Group Institute of Ophthalmology, University College London Moorfields Eye Hospital NHS Foundation Trust, London NIHR Biomedical Research Centre for Ophthalmology, University College London and Moorfields Eye Hospital London Department of Civil and Environmental Engineering , University College London Michigan State University, MI Institute of Child Health, University College London Targeted Genetics Corporation, Seattle Bainbridge J et al N Eng J Med 2008 April [Epub] Lebers amaurosis • first described 1869 • infantile onset rod-cone dystrophy • 2-3 per 100,000 live births • 5% of congenital blindness • AR inheritance • genetically heterogenous • poor vision from infancy • nystagmus • non-recordable ERG Courtesy of Professor Birgit Lorenz LCA Genes Lebercilin CPE290 RDH12 RPE65 1p31.2 • • • • • • • • 14 exons Encodes a 65 KD protein within RPE Crucial to Vit A metabolism in retina responsible for isomerisation of all-trans retinol to 11-cis retinol Mutations cause disease in man (6% LCA) mouse knockout Canine model Gene therapy rescue in mice and dogs Phenotype associated with RPE65 mutations – – – – – – – Infantile onset of visual impairment Light staring Profound night blindness Useful vision at young age Absent rod function Residual cone function Progression to severe visual loss in late teens – Late cell death Subject RJ age 21 VA Rt 2/48 (1.38) Lt 2/60 (1.48) Poor colour vision Visual field loss Non recordable ERG RPE65 gene therapy for LCA • Single gene loss-of-function defect • Condition is severe and has predictably poor prognosis • Window of opportunity for intervention • Intervention might improve function • Target RPE cells can be transduced efficiently by rAAV • Principle is proven in experimental models • UK human trial funded by 970K grant from Department of Health gene therapy intiative Design of clinical trial of RPE65 gene therapy for LCA • Aim: to determine whether gene therapy for retinal dystrophy caused by RPE65 mutations is safe and effective in humans • Study design phase I/II open-label single-centre dose-escalation study • IMP rAAV2.hRPE65p.hRPE65 • Primary outcome safety • Secondary outcome evidence of visual benefit Design of clinical trial of RPE65 gene therapy for LCA Inclusion criteria: • early-onset severe retinal dystrophy • missense mutations in RPE65 • between 8 and 30 yrs of age • in each case, the eye with the worse acuity was selected as the study eye Exclusion criteria: • visual acuity better than 20/120 in the study eye • null mutation in RPE65 • contra-indications for systemic immune suppression Trial stages and dose-escalation Stage 1 of the trial involved: • 3 young adults (aged 16 to 30 years) with advanced degeneration • subretinal injection involving up to 1/3 the total retinal area Subsequent stages will involve: • 9 subjects younger than 16 yrs • dose escalation involving larger areas of the retina Baseline characteristics of subjects ERG Age (yrs) Sex 1 23 M 2 17 3 18 Mutation Amino acid change VA (LogMAR) Ref. error Rods Cones (30Hz flicker) Macula (PERG/ Multifocal) Homozygous [1102T>C] p.Tyr368His 1.16 -3.75/ -0.50 x170 No definite response Residual Undetectable F c. [11+5G>A] +[118G>A] Splice site p.Gly40Ser 1.52 +1.50/ -1.00 x 90 Residual Very reduced and delayed (4.0uV;41ms) Untestable (nystagmus) M c.[16G>T] + [499G>T] p.[Glu6X] + [Asp167Tyr] 0.76 -0.25/ -2.00 x 52 No definite response Very reduced and delayed (10uV;42ms) Undetectable Subretinal injection of rAAV2.hRPE65p.hRPE65 (1x1011/ml; 1ml) QuickTime™ and a Animation decompressor are needed to see this picture. Resolution of induced retinal detachment pre-op #1 #2 #3 during surgery +1 day +4 months Resolution of induced retinal detachment Pre-op +1 day #1 #2 #3 scan unrecordable +2 days Adverse events Transient visual loss (associated with induced retinal detachment) Mild post operative inflammation No surgical complications No immune response to vector or RPE65 Visual acuity following subretinal injection #1 #2 #3 LogMAR (Snellen) Baseline 2 months post-op 4 months post-op 6 months post-op 12 months post-op Study eye 1.16 (20/286) 1.06 (20/226) 0.98 (20/190) 0.86 (20/145) Control eye 0.88 (20/150) 0.90 (20/156) 0.68 (20/95) 0.78 (20/120) Study eye 1.52 (20/662) 1.50 (20/632) 1.58 (20/760) 1.52 (20/662) Control eye 1.62 (20/833) 1.56 (20/662) 1.52 (20/662) 1.58 (20/760) Study eye 0.76 (20/115) 0.90 (20/156) 0.80 (20/126) 0.76 (20/115) Control eye 0.54 (20/69) 0.46 (20/58) 0.40 (20/50) 0.44 (20/55) Microperimetry Subject #1 control eye study eye Subject #2 control eye study eye Subject #3 study eye control eye Microperimetry: Subject #3; 6 months following surgery study eye control eye Microperimetry: Subject #3; 6 months following surgery study eye control eye Microperimetry: Subject #3; 6 months following surgery study eye control eye Dark-adapted perimetry; change in sensitivity over 6 months #1 control eye study eye #2 control eye study eye #3 study eye control eye Field of right eye Field of left eye Dark-adapted perimetry: Subject #3; 6 months following surgery Positive slope P<0.01 P<0.05 P<0.1 P>= 0.1 Negative slope P >= 0.1 P<0.1 P< 0.05 P< 0.01 study (right) eye control (left) eye P< 0.001 Dark-adapted perimetry: Subject #3; 6 months following surgery Positive slope P<0.01 P<0.05 P<0.1 P>= 0.1 Negative slope P >= 0.1 P<0.1 P< 0.05 P< 0.01 study (right) eye control (left) eye P< 0.001 Assessment of visually-guided mobility: UCL Pedestrian Accessibility & Movement Environment Laboratory Assessment of visually-guided mobility Subject #1 Subject #2 Subject #3 4 lux 4 lux 4 lux 240 lux 240 lux 240 lux Assessment of visually-guided mobility Subject #3; 6 months following surgery 4 lux Visually-guided mobility: Subject #3; 6 months following surgery Conclusions • Subretinal vector injection is safe • Even in advanced retinal degeneration, rAAV2.hRPE65p.hRPE65 can improve vision • These results support further studies in children with RPE65 defects Acknowledgements UC L The Moorfields Eye Hospital / UCL Eye Gene Therapy Study Group; G.W. Aylward, D. Boampong, C. Broderick, P. Buch, C. Childs, Y. Duran, D. Ehlich, S. Falk, M. Feely, T. Fujiyama, F. Ikeji, V. Luong, A. Milliken, R. Maclaren, P. Moradi, F. Mowat, M. Richardson, C. Ripamonti, A.G. Robson, H. Rostron, I. Russell-Eggitt, P. Schlottmann, M. Tschernutter and N. Wasseem. Andrew Dick and The UK RPE65 Gene Therapy Data Safety Monitoring Committee Alan Bird, Andrew Webster and Zdenek Gregor: Moorfields RPE65 Gene Therapy Advisory Committee Vivien Perry and Moorfields Pharmaceuticals Graeme Black and the Manchester Regional Genetics Laboratory David Wong The patients and their families Funding UK Department of Health The British Retinitis Pigmentosa Society Special Trustees of Moorfields Eye Hospital The Sir Jules Thorn Charitable Trust The European Union (EVI Genoret and Clinigene programmes) The Wellcome Trust The Medical Research Council Foundation Fighting Blindness USA Fight for Sight The Ulverscroft Foundation Fighting Blindness Ireland Moorfields Eye Hospital and UCL Institute of Ophthalmology Biomedical Research Centre for Ophthalmology JWBB is a Wellcome Advanced Fellow; AJT is a Wellcome Senior Fellow