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Effect of Gene Therapy on Visual Function in Leber's Congenital Amaurosis James W.B. Bainbridge, Ph.D., F.R.C.Ophth., Alexander J. Smith, Ph.D., Susie S. Barker, Ph.D., Scott Robbie, M.R.C.Ophth., Robert Henderson, M.R.C.Ophth., Kamaljit Balaggan, M.R.C.Ophth., Ananth Viswanathan, M.D., F.R.C.Ophth., Graham E. Holder, Ph.D., Andrew Stockman, Ph.D., Nick Tyler, Ph.D., Simon Petersen-Jones, Ph.D., Shomi S. Bhattacharya, Ph.D., Adrian J. Thrasher, Ph.D., M.R.C.P., F.R.C.P., Fred W. Fitzke, Ph.D., Barrie J. Carter, Ph.D., Gary S. Rubin, Ph.D., Anthony T. Moore, F.R.C.Ophth., and Robin R. Ali, Ph.D.
Early-onset, severe retinal dystrophy caused by mutations in the gene encoding reti- nal pigment epithelium–specific 65-kDa protein (RPE65) is associated with poor vi- sion at birth and complete loss of vision in early adulthood. We administered to three young adult patients subretinal injections of recombinant adeno-associated virus vector 2/2 expressing RPE65 complementary DNA (cDNA) under the control of a human RPE65 promoter. There were no serious adverse events. There was no clinically significant change in visual acuity or in peripheral visual fields on Gold- mann perimetry in any of the three patients. We detected no change in retinal re- sponses on electroretinography. One patient had significant improvement in visual From the Institute of Ophthalmology, Uni- function on microperimetry and on dark-adapted perimetry. This patient also versity College London (J.W.B.B., A.J.S., S.S. Barker, S.R., R.H., K.B., A.V., G.E.H., showed improvement in a subjective test of visual mobility. These findings provide A.S., S.S. Bhattacharya, F.W.F., G.S.R., support for further clinical studies of this experimental approach in other patients A.T.M., R.R.A.); Moorfields Eye Hospital with mutant RPE65. (ClinicalTrials.gov number, NCT00643747.) (J.W.B.B., A.V., G.E.H., A.T.M.); the Na-tional Institute of Health Research Bio-medical Research Centre for Ophthal-mology, University College London and Moorfields Eye Hospital (J.W.B.B., G.S.R., A.T.M., R.R.A.); the Department of Civil and Environmental Engineering, Univer- Leber's congenital amaurosis is a term used to describe a group of recessively inherited, severe, infantile-onset rod–cone dystrophies.1 Mutation of sity College London (N.T.); and the Insti- one of several genes, including RPE65, causes disease that involves impaired tute of Child Health, University College vision from birth2,3 and typically progresses to blindness in the third decade of life. London (A.J.T., R.R.A.) — all in London; Michigan State University, East Lansing There is no effective treatment. RPE65 is expressed in the retinal pigment epitheli- (S.P.-J.); and Targeted Genetics Corpora- um and encodes a 65-kD protein that is a key component of the visual cycle,1,4-8 a tion, Seattle (B.J.C.). Address reprint re- biochemical pathway that regenerates the visual pigment after exposure to light.9-14 quests to Dr. Ali at the Institute of Oph- thalmology, University College London, A lack of functional RPE65 results in deficiency of 11-cis retinal so that rod photo- Bath St., London EC1V 9EL, United King- receptor cells are unable to respond to light. Cone photoreceptor cells may have dom, or at [email protected].
access to 11-cis–retinaldehyde chromophore through an alternative pathway that does Drs. Bainbridge and Smith contributed not depend on retinal pigment epithelium–derived RPE65,15,16 thus allowing cone- equally to this article.
mediated vision in children with Leber congenital amaurosis. However, progressive This article (10.1056/NEJMoa0802268) was degeneration of cone photoreceptor cells ultimately results in loss of cone-mediated published at www.nejm.org on April 27, Although the retinal dystrophy caused by defects in RPE65 is severe, features of N Engl J Med 2008;358.
the disorder suggest that it may respond to gene-replacement therapy. There is use- Copyright 2008 Massachusetts Medical Society. n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. ful visual function in childhood, and retinal ducted in compliance with Good Clinical Practice imaging suggests that photoreceptor-cell death guidelines according to the European Clinical occurs late in the disease process.3 Gene trans- Trials Directive (Directive 2001 EU/20/EC) and fer therefore has the potential to improve visual the Declaration of Helsinki.
function as well as preserve existing vision. Before administration of the vector, we evalu- Gene-replacement therapy has been shown to ated the retinal structure and function by means improve visual function in the Swedish Briard of clinical assessment, retinal imaging, psycho- dog, a naturally occurring animal model with physical techniques, and electrodiagnostic meth- mutated RPE65.17 Subretinal delivery of recombi- ods. Retinal imaging techniques included color nant adeno-associated virus vector containing the fundus photography, fundus autofluorescence RPE65 cDNA results in improved retinal function imaging, and optical coherence tomography to and improved vision, as determined by visual determine retinal thickness and integrity. We mobility in low light.18-22 measured visual acuity, contrast sensitivity, color The purpose of this study was to determine vision, and cone flicker sensitivities. We investigat- whether gene therapy for retinal dystrophy caused ed the patients' visual fields by means of micro- by RPE65 mutations was associated with immedi- perimetry (see the Supplementary Appendix), ately obvious adverse events and whether efficacy Goldmann dynamic perimetry, and photopic and could be demonstrated in humans. In this explor- scotopic (dark-adapted) automated static perim- atory, open-label, single-center study involving etry (see the Supplementary Appendix). All testing three young adults, each of whom received a was performed according to standardized, de- single subretinal injection of recombinant adeno- tailed protocols, with controlled room lighting, associated virus 2/2.hRPE65p.hRPE65, the prima- a dark-adaptation period, and a fixed sequence ry outcome was safety, and the secondary out- of test patterns. Both microperimetry and dark- come was evidence of efficacy in terms of visual adapted perimetry are fully automated, so there was little opportunity for experimenter bias. We determined the visual mobility of the patients at different illumination levels by measuring their ability to navigate a simulated street scene (Fig. 1 Patients and Study Design
in the Supplementary Appendix). Electrophysio- In this study, we included young adults (17 to 23 logical evaluation included full-field, pattern, and years of age) with early-onset, severe retinal dys- multifocal electroretinography performed to in- trophy caused by missense mutations in RPE65 corporate the standards and guidelines of the (Table 1 of the Supplementary Appendix, avail- International Society for Clinical Electrophysiol- able with the full text of this article at www.nejm. ogy of Vision.
org). We excluded persons with visual acuity in We repeated assessments of visual function the study eye that was better than 20/120 on the and immune status (see below) at 2, 4, 6, and 12 Snellen visual acuity scale, null mutations, and months (the latter for Patient 1 only; Patients 2 contraindications to systemic immunosuppres- and 3 have not yet reached the 12-month point) sion, as well as women who were pregnant or after administration of the vector. The end point lactating. A National Health Service diagnostic for toxic effects for each patient was a grade 3 laboratory (Manchester Regional Genetics Labo- adverse event, defined as loss of visual acuity by ratory) confirmed the genotypes of potential sub- 15 or more letters according to the Early Treat- jects. In each patient, the eye with the worse acuity ment Diabetic Retinopathy Study scale (on which was selected as the study eye. The contralateral 20/20 denotes perfect vision), or severe, unrespon- eye was used as a control.
sive intraocular inflammation. The end point for The study was approved by the U.K. Gene efficacy for each patient was defined as any im- Therapy Advisory Committee, the Medicines and provement in visual function that was greater Health Products Regulatory Authority, the Moor- than the test–retest difference for each technique. fields Research Governance Committee, and the The assay of immune response and detection of local research ethics committee. All patients gave disseminated recombinant adeno-associated virus written informed consent. The study was con- are described in the Supplementary Appendix.
n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. Recombinant Adeno-Associated Virus
limited degree of residual retinal function de- and Subretinal Delivery
spite advanced retinal degeneration, and they The tgAAG76 vector is a recombinant adeno- might therefore be expected to benefit from inter- associated virus vector of serotype 2. The vector vention.
contains the human RPE65 coding sequence driven We performed vitrectomy and subretinal injec- by a 1400-bp fragment of the human RPE65 pro- tion of the vector without complication in each moter and terminated by the bovine growth hor- patient (Fig. 1 and Video 1). The vitreous gel was
mone polyadenylation site, as described else- relatively degenerate; a posterior vitreous detach- where.21 The vector was produced by Targeted ment was present in Patient 2 and was readily Genetics Corporation according to Good Manu- induced in Patients 1 and 3 by active aspiration facturing Practice guidelines with the use of a at the optic disk with the use of the vitreous cut- B50 packaging cell line,23 an adenovirus–adeno- ter. To deliver the vector to the relatively well- associated virus hybrid shuttle vector containing preserved retina at the posterior pole, we per- the tgAAG76 vector genome, and an adenovirus formed a retinotomy superior to the proximal 5 helper virus. The vector was filled in a buffered part of the superotemporal vascular arcade. To saline solution at a titer of 1×1011 vector particles minimize injection of the vector into the vitre- per milliliter and frozen in 1-ml aliquots at −70°C. ous or choroid, we first induced a small detach- Patients 1, 2, and 3 underwent surgery on ment of the neurosensory retina, using Hartmann's February 7, April 25, and July 11, 2007, respective- solution before injecting up to 1 ml of recombi- ly. After three-port vitrectomy, we administered nant adeno-associated virus vector (thus creating up to 1 ml of recombinant adeno-associated virus a "bleb") through the same single retinotomy. In vector by means of a subretinal cannula (de Juan, Patient 2, the bleb of the vector extended spon- Synergetics) to the subretinal space of one eye, taneously across the macula. We actively manipu- involving up to one third of the total retinal area, lated the bleb in Patients 1 and 3 — to involve including the macula. To reduce the possibility the macula — by injecting air into the vitreous of clinically significant intraocular inflammation, cavity. We caused no iatrogenic retinal tears, and patients were given a 5-week course of oral pred- we left the vector in situ under fluid without nisolone, at a dose of 0.5 mg per kilogram of retinopexy or intraocular tamponade. On clinical body weight for 1 week before administration of examination 24 hours after surgery, the induced the vector, 1 mg per kilogram for the first week retinal detachment had almost fully resolved in after administration, 0.5 mg per kilogram for each patient (Fig. 1A). Optical coherence tomog- the second week, 0.25 mg per kilogram for the raphy showed minimal persistent subretinal fluid third week, and 0.125 mg per kilogram for the at the macula that resolved 2 to 3 days after fourth week. Patients received betamethasone surgery (Fig. 1B). On clinical examination, the and cefuroxime subconjunctivally at the comple- appearance of the retinas was unchanged for tion of surgery and topical treatment with 0.5% the duration of the follow-up period (up to 12 chloramphenicol four times a day for 7 days, 0.1% months).
dexamethasone four times a day for 4 weeks, We detected no dissemination of the vector, and 1% atropine twice a day for 7 days after as assessed by means of polymerase-chain-reac- surgery. We performed a clinical examination, tion amplification of DNA isolated from samples fundus photography, and ocular coherence tomog- of tears, serum, and saliva collected 1 day and 30 raphy (Stratus OCT, Carl Zeiss Meditec) at fre- days after administration of the vector and from quent intervals in the early postoperative period semen collected at 30 days (data not shown). We to monitor for retinal reattachment and to iden- observed mild, self-limiting postoperative intra- tify any intraocular inflammation.
ocular inflammation, which typically follows vit- rectomy. There were no other adverse events. We found no evidence of cystoid macular edema clinically or on optical coherence tomography. Each patient had little or no vision in low light We detected no specific cellular or humoral im- from an early age but retained some limited vi- mune responses to adeno-associated virus capsid sual function in good lighting conditions. We (Fig. 2 of the Supplementary Appendix) or spe- selected these patients because they retained a cific humoral responses to the transgene prod- n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. 1 Day after Surgery
4 Months after Surgery
Patient 1
Patient 2
Patient 3
1 Day after Surgery
2 Days after Surgery
Patient 1
Patient 2
Scan unrecordable Patient 3
Figure 1. Images of the Fundus and Maculae before and after Experimental Treatment.
In Panel A, fundus photographs show the AUTHOR:
ce of the retina in each patient before administration of the vector (before surgery), immediately after subreFIGURE: on of the vector (during surgery), and at 1 day and 4 months after surgery. The site of injection CASE of the vector is indicated by white arrowRevised s (see Video 1). Panel B shows cross-sec- tional images of the retina obtained by optical coherence tomogra 4-C phy with th SIZE
e use of six 6-mm radial-line scans and a standardized mapping protocol to show the structure o H/T n each patient. The presence of residual subretinal vector 1 day after surgery is shown (arrows) in Patients 1 and 3 by an area of low signal (black). Images in
Patient 2 were unrecordable 1 day after surgery AUTHOR, PLEASE NOTE:
because of high-ampli tude nystagmus.
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Please check carefully.
uct (Fig. 2 and Table 2 of th 35821 plementary 05-22-08 eased predictably in asso- Appendix). We detected a small increase in non- ciation with the temporary retinal detachment specific activation of T cells in two patients, induced by administration of the vector and re- which is consistent with a rebound in the num- turned to preoperative levels by 6 months (Table bers of some lymphocyte subgroups after the 1). We observed no clinically significant improve- withdrawal of corticosteroids (Fig. 2A of the ment in visual acuity in any of the three patients (Table 1) or any change in peripheral visual n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. Table 1. Visual Acuities and Contrast Sensitivities at Baseline and in the Postoperative Period.*
Patient No. and Test
Study eye — logMAR (Snellen) Control eye — logMAR (Snellen) 0.88 (20/150) Study eye — logCS Control eye — logCS Study eye — logMAR (Snellen) Control eye — logMAR (Snellen) 1.62 (20/833) Study eye — logCS Control eye — logCS Study eye — logMAR (Snellen) Control eye — logMAR (Snellen) 0.54 (20/69) Study eye — logCS Control eye — logCS * The logarithm of the minimum angle of resolution (logMAR) is used here because it allows comparisons of visual acu- ity scores that are more precise than are scores on the Snellen visual acuity scale. LogCS denotes the logarithm of con- trast sensitivity.
fields on Goldmann perimetry testing. We de- nonsignificant decreases and red bars represent- tected no change in retinal responses to flash or ing significant decreases in sensitivity. In the pattern electroretinography. Before surgery, Pa- right (study) eye, 37 locations showed signifi- tient 2 had high-amplitude nystagmus, which did cant improvements in sensitivity (P<0.01). The not change after treatment.
mean sensitivity at nine locations in the infero- Microperimetry showed no change in retinal nasal region improved from 4 dB at baseline to function in Patients 1 and 2 but improved retinal 26 dB after treatment, and nine locations in the function in Patient 3 (Fig. 2A). The baseline data inferotemporal quadrant improved from 7 dB to for Patient 3 were obtained from the average of 28 dB. This finding is equivalent to an improve- two measurements taken 1 week apart. Measure- ment in sensitivity of more than 20 dB for these ments were performed on the same retinal loci 18 locations, or 100 times the sensitivity thresh- by registering the fundus image with the base- old observed at baseline.
line image. In an area extending from the outer Visual mobility in low light was unchanged in macula to a point beyond the major vascular Patients 1 and 2 but improved in Patient 3 (Fig. 3 arcade, the retinal sensitivity improved progres- and Video 2). In bright conditions, the visually sively in the right (study) eye by as much as 14 dB guided mobility in Patient 3 was within normal (a factor of 25). Thus, the patient could see small limits at baseline and follow-up. Under low illu- spots of light that were 1/25th as bright as those mination at baseline, the visual performance of that could be seen before treatment. There was Patient 3 was very poor with the study eye as no improvement in the left (control) eye.
compared with the control eye (with which he Dark-adapted perimetry showed no change in made no errors). At follow-up, we observed a retinal function in Patients 1 and 2 but showed small change for the control eye. We attribute improved retinal function in Patient 3 (Fig. 2). In this change to a general learning effect; a simi- Patients 1 and 2, there was no single location lar improvement in travel time to complete the that showed significant improvement or deterio- course under dim illumination was also observed ration (P<0.05). In Patient 3, some locations in in Patient 1. However, after administration of the the left (control) eye had yellow bars representing vector, the travel time for Patient 3 improved n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. (Control) Eye
Fundus of the Left
Visual Field of the
(Study) Eye
Right Eye
Fundus of the Right
Visual Field of the
Patient 3
SIZE 5 col
(Study) Ey
Fundus of the Left
Visual Field of the
Please check carefully.
AUTHOR, PLEASE NOTE:
Right Eye
Fundus of the Right
Visual Field of the
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Patient 2
12 Months
(Study) Eye
Fundus of the Left
Visual Field of the
Right Eye
Fundus of the Right
Visual Field of the
Patient 1
12 Months
n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. nally without causing tears in thinned, degener- Figure 2 (facing page). Assessment of Visual Function
ate retina. To investigate the effect of RPE65 gene by Microperimetry and Dark-Adapted Perimetry.
therapy on macular function, we included the The upper portion of each panel shows the micro-perimetry results for each patient. The size of the cir- macula in the area of vector administration by cular symbols indicates retinal sensitivity on a scale of injection of air into the vitreous cavity when nec- 0 to 14 dB. The change in sensitivity in Patient 3 at each essary. An important concern was that detach- tested location from baseline to 6 months' follow-up ment of the neurosensory retina as a result of was evaluated with pointwise linear regression. Of the subretinal injection could adversely affect vision 55 locations that were tested, 12 (indicated by aster-isks) had significant positive slopes (P<0.05), ranging in the long term, particularly if the detachment from 12 to 28 dB per year. We would expect no more involved the macula. We found that the induced than three points to pass this test by chance alone. retinal detachment resolved spontaneously and A major change in sensitivity of 9 dB or more (an in- fully within a few days after injection, with sub- crease in sensitivity by a factor of 8) is indicated by a sequent recovery of vision to preexisting levels. plus sign. The lower portion of each panel shows the dark-adapted perimetry results for each patient. The We did not identify any clinically significant ad- analysis provides significance levels for change over verse effect of subretinal vector delivery, and the time at each individual test location. We made a series absence of systemic dissemination suggests that of eight measurements during the 6-month follow-up any extraocular leakage of vector from the sub- period. Each measurement is depicted by a bar; the retinal space was minimal.
lengths of the bars represent sensitivity, with the long bars showing loss of sensitivity and the short bars To minimize the possibility of intraocular in- showing normal sensitivity. Yellow indicates a decline flammation elicited by vector capsid proteins, we in sensitivity that is not significant, red indicates a de- used perioperative systemic immunosuppressive cline that is significant (P<0.05), and green indicates agents. Because of concerns about the possibil- an improvement that is significant (P<0.01). One exam- ity of immune responses to the transgene prod- ple, at the X/Y coordinate –9, +3 of the right eye of Pa-tient 3, is magnified to show the sensitivity measure- uct, we used a tissue-specific promoter and ex- ments going from baseline on the left sequentially cluded patients with null mutations. We observed through the follow-up assessments on the right. In this no clinically significant intraocular inflammation example, the long gray bars on the left indicate that and detected no immune responses to either the patient was unable to see the light stimulus at maxi- adeno-associated virus capsid or RPE65.
mum intensity. The shorter bars on the right indicate progressive improvement in sensitivity (P<0.01).
We found consistent evidence, on the basis of both microperimetry and dark-adapted perim- etry, of improved vision in one patient (Patient from 77 seconds to 14 seconds for the study eye, 3). The improvement in his visual mobility in and mobility errors decreased from 8 to 0. Simi- low light was also substantially greater than lar results were obtained in a second follow-up that which would be due to a modest learning test 4 weeks later.
effect and was consistent with the improvement in visual function established by means of pe- rimetry. It is not clear whether the improvement in visual responses in the peripheral macula is Recombinant adeno-associated virus 2/2 vector rod-mediated or cone-mediated. Neither can we efficiently transduces retinal pigment epithelial be sure that the improvement in visual function cells after subretinal delivery in animal models.24 is entirely due to enhanced levels of RPE65 in the We investigated the feasibility of subretinal vec- retina. Evidence for this could be obtained only tor injection in patients with advanced retinal by biopsy of retinal material, which would be degeneration and found that we could achieve unsafe and unethical. Central macula function this outcome predictably and without immediate and visual acuity did not improve, despite expo- adverse events, using a transvitreal, transretinal sure of this region to the vector; this may be due approach after pars plana vitrectomy. A relatively either to amblyopia (i.e., the study eye was am- degenerate vitreous facilitated detachment and blyopic) or to a requirement for higher levels of removal of the posterior vitreous cortex, which RPE65 at the fovea. Visual function improved in otherwise might have resisted passage of the fine only one patient (Patient 3); he had better base- cannula. We found that we could deliver through line visual acuity in both the study (amblyopic) a single retinotomy up to 1 ml of vector subreti- eye and the control eye than either of the other n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. A Patient 1
Travel Time
Total Errors
Travel Time
Total Errors
B Patient 2
Travel Time
Total Errors
Travel Time
Total Errors
C Patient 3
Travel Time
Total Errors
Travel Time
Total Errors
Figure 3. Assessment of Visual Mobility.
Visually guided mobility was assessed at the ICM Pedestrian Accessibility and Movement Environment Laboratory at University College London (see Fig. 1 and the videos of the Supplement REG Appendix). Panels A, B, and C show data for P 3rd atients 1, 2, and 3, respectively, at ambient il- lumination levels of 4 lux and 240 lux. Averag CASE e travel times for completing the course (Revised ±1 SD) for five control subjects are indicated.
patients. He was not the youngest patient, but he e AUTHOR, PLEASE NOTE: ration is delayed in any of the patients will be-
Figure has been redrawn and type has been reset.
probably had less advanced retinal disease at Please check carefully. come apparent only after several years.
baseline, which may explain why the improve- The results of this study suggest that subreti- ment in this patient 35821 ot observed in the nal ad 05-23-08 ration of recombinant adeno-asso- other patients. Whether further retinal degen- ciated virus vector is not associated with imme- n engl j med 10.1056/nejmoa0802268 Downloaded from www.nejm.org by HANNAH BOYD on April 28, 2008 . Copyright 2008 Massachusetts Medical Society. All rights reserved. diate adverse events in patients with severe retinal Drs. Bainbridge and Ali report being the inventors associ- dystrophy and that adeno-associated virus–medi- ated with a U.S. patent application assigned to University Col- lege London and Targeted Genomics Corporation entitled, ated RPE65 gene therapy can lead to modest im- "Devices and methods for delivering polynucleotides into reti- provements in visual function, even in patients nal cells of the macula and fovea"; Drs. Fitzke and Viswanathan with advanced degeneration. Our findings pro- report being two of the inventors of Progressor software, the intellectual property rights for which are owned by University vide support for the development of further clini- College London and Moorfields Eye Hospital and licensed to cal studies in children with RPE65 deficiency; Medisoft; Dr. Carter reports being an employee of Targeted Ge- these children are more likely to benefit than netics and receiving consulting fees from Sangamo Biosciences. No other potential conflict of interest relevant to this article was reported.
Supported by grants from the U.K. Department of Health, the We thank Andrew Dick and the U.K. RPE65 Gene Therapy British Retinitis Pigmentosa Society, and the Special Trustees of Data and Safety Monitoring Committee; Alan Bird and the Moorfields Eye Hospital, and by the Sir Jules Thorn Charitable Moorfields Eye Hospital RPE65 Gene Therapy Advisory Commit- Trust, the Wellcome Trust, the European Union (EVI-Genoret tee; Vivien Perry and Moorfields Pharmaceuticals; Graeme Black, and Clinigene programs), the Medical Research Council, Foun- for help with genotyping; David Wong, for advice on surgical dation Fighting Blindness, Fight for Sight, the Ulverscroft Foun- techniques; and the patients and their families for their effort dation, Fighting Blindness (Ireland), Moorfields Eye Hospital, and commitment.
and Institute of Ophthalmology Biomedical Research Centre for Ophthalmology, University College London.
The following investigators, who are members of the Moorfields Eye Hospital and University College London Eye Gene Therapy Study Group, participated in this trial: 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.
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