Outcomes and Adverse Effects of Voretigene Neparvovec Treatment for Biallelic RPE65-Mediated Inherited Retinal Dystrophies in a Cohort of Patients from a Single Center.

Our study evaluated the morphological and functional outcomes, and the side effects, of voretigene neparvovec (VN) gene therapy for RPE65-mediated inherited retinal dystrophies (IRDs) in 12 eyes (six patients) at the Oxford Eye Hospital with a mean follow-up duration of 8.2 (range 1-12) months. All patients reported a subjective vision improvement 1 month after gene therapy. Best-corrected visual acuity (BCVA) remained stable (baseline: 1.28 (±0.71) vs. last follow-up: 1.46 (±0.60); p = 0.25). Average white Full-Field Stimulus Testing (FST) showed a trend towards improvement (baseline: -4.41 (±10.62) dB vs. last follow-up: -11.98 (±13.83) dB; p = 0.18). No changes in central retinal thickness or macular volume were observed. The side effects included mild intraocular inflammation (two eyes) and cataracts (four eyes). Retinal atrophy occurred in 10 eyes (eight mild, two severe) but did not impact FST measurements during the follow-up period. Increased intraocular pressure (IOP) was noted in three patients (six eyes); four eyes (two patients) required glaucoma surgery. The overall safety and effectiveness of VN treatment in our cohort align with previous VN clinical trials, except for the higher occurrence of retinal atrophy and increased IOP in our cohort. This suggests that raised IOP and retinal atrophy may be more common than previously reported.

Amiloride does not protect retinal nerve fibre layer thickness in optic neuritis in a phase 2 randomised controlled trial.

BACKGROUND: Recent basic and clinical evidence suggests amiloride may be neuroprotective in multiple sclerosis (MS) through the blockade of the acid sensing ion channel (ASIC). OBJECTIVE: To examine the neuroprotective efficacy of amiloride in acute optic neuritis (ON). METHODS: A total of 48 patients were recruited to a phase 2, double blind, single site, randomised controlled trial. Scanning laser polarimetry (GDx) at 6 months was the primary outcome measure and optical coherence tomography (OCT) and visual and electrophysiological measures were secondary outcome measures. Participants aged 18-55 years, ≤28 days of onset of first episode unilateral ON, were randomised to amiloride (10 mg daily for 5 months) or placebo ( clinicaltrials.gov , NCT 01802489). RESULTS: Intention-to-treat (ITT) cohort consisted of 43 patients; 23 placebo and 20 amiloride. No significant drug-related adverse events occurred. No significant differences were found in GDx ( p = 0.840). Visual evoked potentials (VEP) were significantly prolonged in the amiloride group compared to placebo ( p = 0.004). All other secondary outcome measures showed no significant difference. Baseline analysis of OCT data demonstrated a significant pre-randomisation thinning of ganglion cell layer. CONCLUSION: Amiloride has not demonstrated any neuroprotective benefit within this trial paradigm, but future neuroprotective trials in ON should target the window of opportunity to maximise potential neuroprotective benefit.

Electrophysiological verification of enhanced S-cone syndrome caused by a novel c.755T>C NR2E3 missense variant.

BACKGROUND: Nuclear hormone receptor gene, NR2E3, plays a critical role in retinogenesis and determination of the rod photoreceptor phenotype. Mutations in NR2E3 typically lead to recessive enhanced S-cone syndrome (ESCS), where affected individuals show higher sensitivity to short wavelength light and early onset rod dysfunction. Patients with ESCS present in early childhood with nyctalopia, enhanced sensitivity to blue light and display a very heterogeneic retinal phenotype with varying degrees of clumped pigmentation and occasional retinoschisis. PURPOSE: To confirm the pathogenicity of a novel mutation in NR2E3 using electrophysiological studies. MATERIALS AND METHODS: Patient underwent detailed clinical evaluation and ophthalmic imaging followed by next generation sequencing analysis and electrophysiological studies. RESULTS: We describe a case of a young man of Greek descent with a family history of retinal degeneration. His fundal features at presentation were atypical of ESCS, with striking macular involvement in both eyes, including fibrotic subretinal material overlying the pigment epithelial detachment in one eye and schisis in the other. Genetic testing revealed a novel homozygous variant in NR2E3 gene of uncertain pathogenicity. Instead of performing further genetic analyses, electrophysiological studies showed pathognomonic changes in the S-cone response. CONCLUSIONS: With the recent clinical endorsement of a gene therapy for RPE65 related-inherited retinal degeneration it is of paramount importance to correctly identify the pathogenic genetic mutation. In this particular syndrome, we highlight the value of electrophysiology to confirm the pathogenicity of a novel mutation in NR2E3 and aid the diagnosis of ESCS, with potential for gene therapy in the future.

Assessment of the Electronic Retinal Implant Alpha AMS in Restoring Vision to Blind Patients with End-Stage Retinitis Pigmentosa.

PURPOSE: To report the initial efficacy results of the Retina Implant Alpha AMS (Retina Implant AG, Reutlingen, Germany) for partial restoration of vision in end-stage retinitis pigmentosa (RP). DESIGN: Prospective, single-arm, investigator-sponsored interventional clinical trial. Within-participant control comprising residual vision with the retinal implant switched ON versus OFF in the implanted eye. PARTICIPANTS: The Retina Implant Alpha AMS was implanted into the worse-seeing eye of 6 participants with end-stage RP and no useful perception of light vision. Eligibility criteria included previous normal vision for ≥12 years and no significant ocular or systemic comorbidity. METHODS: Vision assessments were scheduled at 1, 2, 3, 6, 9, and 12 months postimplantation. They comprised tabletop object recognition tasks, a self-assessment mobility questionnaire, and screen-based tests including Basic Light and Motion (BaLM), grating acuity, and greyscale contrast discrimination. A full-field stimulus test (FST) was also performed. MAIN OUTCOME MEASURES: Improvement in activities of daily living, recognition tasks, and assessments of light perception with the implant ON compared with OFF. RESULTS: All 6 participants underwent successful implantation. Light perception and temporal resolution with the implant ON were achieved in all participants. Light localization was achieved with the implant ON in all but 1 participant (P4) in whom the chip was not functioning optimally because of a combination of iatrogenic intraoperative implant damage and incorrect implantation. Implant ON correct grating detections (which were at chance level with implant OFF) were recorded in the other 5 participants, ranging from 0.1 to 3.33 cycles/degree on 1 occasion. The ability to locate high-contrast tabletop objects not seen with the implant OFF was partially restored with the implant ON in all but 1 participant (P4). There were 2 incidents of conjunctival erosion and 1 inferotemporal macula-on retinal detachment, which were successfully repaired, and 2 incidents of inadvertent damage to the implant during surgery (P3 and P4). CONCLUSIONS: The Alpha AMS subretinal implant improved visual performance in 5 of 6 participants and has exhibited ongoing function for up to 24 months. Although implantation surgery remains challenging, new developments such as OCT microscope guidance added refinements to the surgical technique.

Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations.

Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy). Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640). Functional outcome measures included (1) screen-based standardized 2- or 4-alternative forced-choice (AFC) tests of light perception, light localization, grating detection (basic grating acuity (BaGA) test), and Landolt C-rings; (2) gray level discrimination; (3) performance during activities of daily living (ADL-table tasks). Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree) in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA) assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10) were discerned. Improvements (power ON vs. OFF) of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs) were transient and mostly of mild to moderate intensity. Conclusions: Psychophysical and subjective data show that RETINA IMPLANT Alpha AMS is reliable, well tolerated and can restore limited visual functions in blind patients with degenerations of the outer retina. Compared with the previous implant Alpha IMS, longevity of the new implant Alpha AMS has been considerably improved. Alpha AMS has meanwhile been certified as a commercially available medical device, reimbursed in Germany by the public health system.

Subretinal Visual Implant Alpha IMS--Clinical trial interim report.

A subretinal visual implant (Alpha IMS, Retina Implant AG, Reutlingen, Germany) was implanted in 29 blind participants with outer retinal degeneration in an international multicenter clinical trial. Primary efficacy endpoints of the study protocol were a significant improvement of activities of daily living and mobility to be assessed by activities of daily living tasks, recognition tasks, mobility, or a combination thereof. Secondary efficacy endpoints were a significant improvement of visual acuity/light perception and/or object recognition (clinicaltrials.gov, NCT01024803). During up to 12 months observation time twenty-one participants (72%) reached the primary endpoints, of which thirteen participants (45%) reported restoration of visual function which they use in daily life. Additionally, detection, localization, and identification of objects were significantly better with the implant power switched on in the first 3 months. Twenty-five participants (86%) reached the secondary endpoints. Measurable grating acuity was up to 3.3 cycles per degree, visual acuities using standardized Landolt C-rings were 20/2000, 20/2000, 20/606 and 20/546. Maximal correct motion perception ranged from 3 to 35 degrees per second. These results show that subretinal implants can restore very-low-vision or low vision in blind (light perception or less) patients with end-stage hereditary retinal degenerations.

Retinal gene therapy in patients with choroideremia: initial findings from a phase 1/2 clinical trial.

BACKGROUND: Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1). We assessed the effects of retinal gene therapy with an adeno-associated viral (AAV) vector encoding REP1 (AAV.REP1) in patients with this disease. METHODS: In a multicentre clinical trial, six male patients (aged 35-63 years) with choroideremia were administered AAV.REP1 (0·6-1·0×10(10) genome particles, subfoveal injection). Visual function tests included best corrected visual acuity, microperimetry, and retinal sensitivity tests for comparison of baseline values with 6 months after surgery. This study is registered with ClinicalTrials.gov, number NCT01461213. FINDINGS: Despite undergoing retinal detachment, which normally reduces vision, 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. Mean gain in visual acuity overall was 3·8 letters (SE 4·1). Maximal sensitivity measured with dark-adapted microperimetry increased in the treated eyes from 23·0 dB (SE 1·1) at baseline to 25·3 dB (1·3) after treatment (increase 2·3 dB [95% CI 0·8-3·8]). In all patients, over the 6 months, the increase in retinal sensitivity in the treated eyes (mean 1·7 [SE 1·0]) was correlated with the vector dose administered per mm(2) of surviving retina (r=0·82, p=0·04). By contrast, small non-significant reductions (p>0·05) were noted in the control eyes in both maximal sensitivity (-0·8 dB [1·5]) and mean sensitivity (-1·6 dB [0·9]). One patient in whom the vector was not administered to the fovea re-established variable eccentric fixation that included the ectopic island of surviving retinal pigment epithelium that had been exposed to vector. INTERPRETATION: 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. FUNDING: UK Department of Health and Wellcome Trust.

Muscarinic receptor protein expression in the ocular tissues of the chick during normal and myopic eye development.

Muscarinic receptor signalling has been implicated in both the embryonic and postnatal development of ocular structures as well as in myopic eye growth. A radioligand binding assay was used to determine whether changes in muscarinic receptor density and/or affinity occurred in the chick retina, choroid and sclera during early post-hatching development or with the induction of myopia. Specific receptor binding sites were saturable with increasing concentrations of the muscarinic receptor ligand [3H]N-methyl-scopolamine in the retina and choroid but not in the sclera. In normal eyes, binding density in the retina was not altered from age P5 to P10 (447+/-14 vs. 411+/-13 fmol/mg of protein, P=0.07). However, in the choroid, the number of receptor binding sites significantly increased between P5 and P10 (637+/-39 vs. 1125+/-121 fmol/mg of protein, P<0.01). Binding affinity (K(D)) was not altered with age in either the retina or choroid. Myopia was induced in chicks by deprivation of form vision, using translucent diffusers, from age P3. Despite the induction of significant degrees of ocular elongation and myopia at P5 (-8.7+/-0.3 D, P<0.01) and P10 (-22.5+/-1.3 D, P<0.01), neither muscarinic receptor density nor affinity were altered in the retina or choroid of myopic eyes. These findings indicate that regulation of muscarinic receptor numbers in the chick choroid is occurring in normal post-hatching development of this tissue. However, myopic eye enlargement was not associated with changes in muscarinic receptor protein expression in the chick retina and choroid.

Pirenzepine affects scleral metabolic changes in myopia through a non-toxic mechanism.

Whilst the precise mechanism regulating ocular growth is unknown, it has been shown that various pharmacological agents, including the muscarinic receptor antagonists, atropine and pirenzepine, are effective at preventing the development of myopia. A recent study, which demonstrated that muscarinic antagonists reduce the synthesis of glycosaminoglycans and DNA in chick sclera in vitro, led to the suggestion that such drugs may act directly on the sclera, possibly through a toxic mechanism. Accepted markers of scleral metabolism and cell viability were used in conjunction with a non-invasive, physiological method of ocular growth regulation to determine whether the selective muscarinic antagonist pirenzepine inhibits the development of myopia via toxicity to the sclera. Chicks were monocularly deprived (MD) of pattern vision and given daily intravitreal injections of either pirenzepine (700 microg) or saline vehicle into the deprived eye over 5 days. Unoccluded animals also received intravitreal injections of either pirenzepine or saline into one eye (n=6, all groups). The contralateral eye of all animals was left untreated for comparison. Optical and ocular biometric measures were collected on the final experimental day. Following in vivo delivery of [(35)S] labelled sulphate, levels of sulphate incorporation into scleral glycosaminoglycans were measured in proteinase K digests following selective precipitation with alcian blue dye. The DNA content was also assessed through luminescence spectrometry after binding to Hoechst 33258 dye. To allow comparison with an accepted non-invasive, physiological method of ocular growth regulation, myopia was prevented in additional groups of MD animals by allowing 3hr of unoccluded vision each day, over 5 days, before levels of sulphate incorporation were measured. Scleral DNA content, a marker of cell viability, was not significantly altered between treated and control eyes in any injected group. Relative levels of sulphate incorporation (% difference between treated and contralateral control eyes) were significantly lower in the cartilaginous sclera of pirenzepine-MD animals, compared to saline-MD controls (+35.9 +/- 10.1% vs +121.2 +/- 28.6%, P<0.05), after 2hr of incorporation. However, after 6hr incorporation, there was no significant difference in sulphate incorporation in the cartilaginous sclera between the two groups (+87.2 +/- 33.1% vs +111.0 +/- 14.4%, P=0.53). No significant change was found in the levels of glycosaminoglycan synthesis in the fibrous sclera of any pirenzepine treated group, when compared to the appropriate saline control. Relative patterns of sulphate incorporation, between treatment and control groups, were essentially identical at both time points examined, regardless of whether myopia was prevented through pirenzepine injection or periods of unoccluded vision. The present study shows that, at a dose of pirenzepine sufficient to prevent experimentally-induced axial myopia, glycosaminoglycan synthesis in the cartilaginous sclera was significantly reduced for a transient period following the injection. These pirenzepine-induced reductions in glycosaminoglycan synthesis were not caused by direct drug toxicity to scleral cells as these changes were reversible and no significant reduction in DNA content was observed in pirenzepine treated eyes. Similar patterns of scleral glycosaminoglycan synthesis changes were found following the provision of brief periods of unoccluded vision further demonstrating that pirenzepine is effective in myopia prevention via a non-toxic mechanism. Consequently, the prevention of myopia development in chicks, with either pirenzepine or brief periods of unoccluded vision, is associated with the transient modulation of scleral glycosaminoglycan synthesis in the cartilaginous sclera.