Robyn H. Guymer

A single EFEMP1 mutation associated with both Malattia Leventinese and Doyne honeycomb retinal dystrophy

Malattia Leventinese (ML) and Doyne honeycomb retinal dystrophy (DHRD) refer to two autosomal dominant diseases characterized by yellow-white deposits known as drusen that accumulate beneath the retinal pigment epithelium (RPE). Both loci were mapped to chromosome 2p16-21 (Refs 5,6) and this genetic interval has been subsequently narrowed. The importance of these diseases is due in large part to their close phenotypic similarity to age-related macular degeneration (AMD), a disorder with a strong genetic component that accounts for approximately 50% of registered blindness in the Western world. Just as in ML and DHRD, the early hallmark of AMD is the presence of drusen. Here we use a combination of positional and candidate gene methods to identify a single non-conservative mutation (Arg345Trp) in the gene EFEMP1 (for EGF-containing fibrillin-like extracellular matrix protein 1) in all families studied. This change was not present in 477 control individuals or in 494 patients with age-related macular degeneration. Identification of this mutation may aid in the development of an animal model for drusen, as well as in the identification of other genes involved in human macular degeneration.

Safety and Efficacy of a Flexible Dosing Regimen of Ranibizumab in Neovascular Age-Related Macular Degeneration: The SUSTAIN Study

OBJECTIVE To evaluate the safety and efficacy of individualized ranibizumab treatment in patients with neovascular age-related macular degeneration. DESIGN Twelve-month, phase III, multicenter, open-label, single-arm study. PARTICIPANTS A total of 513 ranibizumab-naïve SUSTAIN patients. INTERVENTION Three initial monthly injections of ranibizumab (0.3 mg) and thereafter pro re nata (PRN) retreatment for 9 months based on prespecified retreatment criteria. Patients switched to 0.5 mg ranibizumab after approval in Europe. MAIN OUTCOME MEASURES Frequency of adverse events (AEs), monthly change of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline, the time to first re-treatment, and the number of treatments were assessed. RESULTS A total of 249 patients (48.5%) reported ocular AEs, and 8 (1.5%) deaths, 5 (1.2%) patients with ocular serious AEs of the study eye (retinal hemorrhage, cataract, retinal pigment epithelial tear, reduced visual acuity [VA], vitreous hemorrhage), and 19 (3.7%) patients with arteriothromboembolic events were observed. Most frequent AEs in the study eye were reduced VA (18.5%), retinal hemorrhage (7.2%), increased intraocular pressure (7.0%), and conjunctival hemorrhage (5.5%). The average number of re-treatments from months 3 to 11 was 2.7. Mean best-corrected visual acuity increased steadily from baseline to month 3 to reach +5.8 letters, decreased slightly from month 3 to 6, and remained stable from month 6 to 12, reaching +3.6 at month 12. Mean change in CRT was -101.1 μm from baseline to month 3 and -91.5 μm from baseline to month 12. CONCLUSIONS The safety results are comparable to the favorable tolerability profile of ranibizumab observed in previous pivotal clinical studies; individualized treatment with less than monthly re-treatments shows a similar safety profile as observed in previous randomized clinical trials with monthly ranibizumab treatment. Efficacy outcomes were achieved with a low average number of re-treatments. Visual acuity in SUSTAIN patients with individualized re-treatment based on VA/optical coherence tomography assessment reached on average a maximum after the first 3 monthly injections, decreased slightly under PRN during the next 2 to 3 months, and was then sustained throughout the treatment period.

Efficacy and Safety of Monthly versus Quarterly Ranibizumab Treatment in Neovascular Age-related Macular Degeneration: The EXCITE Study

OBJECTIVE To demonstrate noninferiority of a quarterly treatment regimen to a monthly regimen of ranibizumab in patients with subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). DESIGN A 12-month, multicenter, randomized, double-masked, active-controlled, phase IIIb study. PARTICIPANTS Patients with primary or recurrent subfoveal CNV secondary to AMD (353 patients), with predominantly classic, minimally classic, or occult (no classic component) lesions. INTERVENTION Patients were randomized (1:1:1) to 0.3 mg quarterly, 0.5 mg quarterly, or 0.3 mg monthly doses of ranibizumab. Treatment comprised of a loading phase (3 consecutive monthly injections) followed by a 9-month maintenance phase (either monthly or quarterly injection). MAIN OUTCOME MEASURES Mean change in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 12 and the incidence of adverse events (AEs). RESULTS In the per-protocol population (293 patients), BCVA, measured by Early Treatment Diabetic Retinopathy Study-like charts, increased from baseline to month 12 by 4.9, 3.8, and 8.3 letters in the 0.3 mg quarterly (104 patients), 0.5 mg quarterly (88 patients), and 0.3 mg monthly (101 patients) dosing groups, respectively. Similar results were observed in the intent-to-treat (ITT) population (353 patients). The mean decrease in CRT from baseline to month 12 in the ITT population was -96.0 μm in 0.3 mg quarterly, -105.6 μm in 0.5 mg quarterly, and -105.3 μm in 0.3 mg monthly group. The most frequent ocular AEs were conjunctival hemorrhage (17.6%, pooled quarterly groups; 10.4%, monthly group) and eye pain (15.1%, pooled quarterly groups; 20.9%, monthly group). There were 9 ocular serious AEs and 3 deaths; 1 death was suspected to be study related (cerebral hemorrhage; 0.5 mg quarterly group). The incidences of key arteriothromboembolic events were low. CONCLUSIONS After 3 initial monthly ranibizumab injections, both monthly (0.3 mg) and quarterly (0.3 mg/0.5 mg) ranibizumab treatments maintained BCVA in patients with CNV secondary to AMD. At month 12, BCVA gain in the monthly regimen was higher than that of the quarterly regimens. The noninferiority of a quarterly regimen was not achieved with reference to 5.0 letters. The safety profile was similar to that reported in prior ranibizumab studies.

Common Variants near FRK/COL10A1 and VEGFA are Associated with Advanced Age-related Macular Degeneration

Despite significant progress in the identification of genetic loci for age-related macular degeneration (AMD), not all of the heritability has been explained. To identify variants which contribute to the remaining genetic susceptibility, we performed the largest meta-analysis of genome-wide association studies to date for advanced AMD. We imputed 6 036 699 single-nucleotide polymorphisms with the 1000 Genomes Project reference genotypes on 2594 cases and 4134 controls with follow-up replication of top signals in 5640 cases and 52 174 controls. We identified two new common susceptibility alleles, rs1999930 on 6q21-q22.3 near FRK/COL10A1 [odds ratio (OR) 0.87; P = 1.1 × 10−8] and rs4711751 on 6p12 near VEGFA (OR 1.15; P = 8.7 × 10−9). In addition to the two novel loci, 10 previously reported loci in ARMS2/HTRA1 (rs10490924), CFH (rs1061170, and rs1410996), CFB (rs641153), C3 (rs2230199), C2 (rs9332739), CFI (rs10033900), LIPC (rs10468017), TIMP3 (rs9621532) and CETP (rs3764261) were confirmed with genome-wide significant signals in this large study. Loci in the recently reported genes ABCA1 and COL8A1 were also detected with suggestive evidence of association with advanced AMD. The novel variants identified in this study suggest that angiogenesis (VEGFA) and extracellular collagen matrix (FRK/COL10A1) pathways contribute to the development of advanced AMD.

Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis.

Objective To evaluate the effectiveness of dietary antioxidants in the primary prevention of age related macular degeneration (AMD). Design Systematic review and meta-analysis. Data sources Search of seven databases without limits on year or language of publication, and retrieval of references in pertinent reviews and articles. Methods Two reviewers independently searched the databases and selected the studies, using standardised criteria. Randomised clinical trials and prospective cohort studies were included. Of the 4192 abstracts initially identified, 12 studies (nine prospective cohort studies and three randomised clinical trials) met the selection criteria and were included. Data extraction and study quality evaluation were independently reviewed, using standardised criteria. Results were pooled quantitatively using meta-analytic methods. Results The nine prospective cohort studies included 149 203 people, with 1878 incident cases of early AMD. The antioxidants investigated differed across studies, and not all studies contributed to the meta-analysis of each antioxidant. Pooled results from prospective cohort studies indicated that vitamin A, vitamin C, vitamin E, zinc, lutein, zeaxanthin, α carotene, β carotene, β cryptoxanthin, and lycopene have little or no effect in the primary prevention of early AMD. The three randomised clinical trials did not show that antioxidant supplements prevented early AMD. Conclusions There is insufficient evidence to support the role of dietary antioxidants, including the use of dietary antioxidant supplements, for the primary prevention of early AMD.

Perifoveal Muller Cell Depletion in a Case of Macular Telangiectasia Type 2

PURPOSE To assess the histopathologic changes in a postmortem sample derived from an eye donor with macular telangiectasia (MacTel) type 2 to gain further insight into the cause of the disease. DESIGN Clinicopathological case report. PARTICIPANTS Postmortem tissue was collected from 5 different donors: 1 MacTel type 2 patient; 1 healthy control; 2 type 2 diabetic patients, 1 with retinopathy and 1 without retinopathy; and 1 patient with unilateral Coats disease. METHODS Macular pigment distribution in the posterior part of freshly dissected eyes was documented by macrophotography. Paraffin sections from both the macular and peripheral regions were assessed using antigen retrieval and immunohistochemistry to study the distribution of cell-specific markers. Blood vessels were visualized with antibodies directed against collagen IV and claudin 5; glial cells with antibodies against glial fibrillary acidic protein (GFAP), vimentin, glutamine synthetase (GS), and retinaldehyde binding protein (RLBP1, also known as CRALBP); microglia with an antibody against allograft inflammatory factor 1 (also known as Iba1); and photoreceptors with antibodies against rhodopsin and opsin. Using anatomic landmarks, the sections then were matched with the macular pigment distribution and a fluorescein angiogram of the patient that was obtained before the patients death. MAIN OUTCOME MEASURES Presence and distribution of macular pigment and cell-specific markers. RESULTS Macular pigment was absent in the macula. Furthermore, abnormally dilated capillaries were identified in a macular region that correlated spatially with regions of fluorescein leakage in an angiogram that was obtained 12 years before death. These telangiectatic vessels displayed a marked reduction of the basement membrane component collagen IV, indicating vascular pathologic features. The presence of GFAP was limited to retinal astrocytes, and no reactive Müller cells were identified. Importantly, reduced immunoreactivity with Müller cell markers (vimentin, GS, and RLBP1) in the macula was observed. The area that lacked Müller cells corresponded with the region of depleted macular pigment. CONCLUSIONS These findings suggest that macular Müller cell loss or dysfunction is a critical component of MacTel type 2, which may have implications for future treatment strategies.

Identification of a rare coding variant in complement 3 associated with age-related macular degeneration

Macular degeneration is a common cause of blindness in the elderly. To identify rare coding variants associated with a large increase in risk of age-related macular degeneration (AMD), we sequenced 2,335 cases and 789 controls in 10 candidate loci (57 genes). To increase power, we augmented our control set with ancestry-matched exome-sequenced controls. An analysis of coding variation in 2,268 AMD cases and 2,268 ancestry-matched controls identified 2 large-effect rare variants: previously described p.Arg1210Cys encoded in the CFH gene (case frequency (fcase) = 0.51%; control frequency (fcontrol) = 0.02%; odds ratio (OR) = 23.11) and newly identified p.Lys155Gln encoded in the C3 gene (fcase = 1.06%; fcontrol = 0.39%; OR = 2.68). The variants suggest decreased inhibition of C3 by complement factor H, resulting in increased activation of the alternative complement pathway, as a key component of disease biology.

First-in-Human Trial of a Novel Suprachoroidal Retinal Prosthesis

Retinal visual prostheses (“bionic eyes”) have the potential to restore vision to blind or profoundly vision-impaired patients. The medical bionic technology used to design, manufacture and implant such prostheses is still in its relative infancy, with various technologies and surgical approaches being evaluated. We hypothesised that a suprachoroidal implant location (between the sclera and choroid of the eye) would provide significant surgical and safety benefits for patients, allowing them to maintain preoperative residual vision as well as gaining prosthetic vision input from the device. This report details the first-in-human Phase 1 trial to investigate the use of retinal implants in the suprachoroidal space in three human subjects with end-stage retinitis pigmentosa. The success of the suprachoroidal surgical approach and its associated safety benefits, coupled with twelve-month post-operative efficacy data, holds promise for the field of vision restoration. Trial Registration Clinicaltrials.gov NCT01603576

Hypomethylation of the IL17RC promoter associates with age-related macular degeneration.

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the elderly population worldwide. Although recent studies have demonstrated strong genetic associations between AMD and SNPs in a number of genes, other modes of regulation are also likely to play a role in the etiology of this disease. We identified a significantly decreased level of methylation on the IL17RC promoter in AMD patients. Furthermore, we showed that hypomethylation of the IL17RC promoter in AMD patients led to an elevated expression of its protein and messenger RNA in peripheral blood as well as in the affected retina and choroid, suggesting that the DNA methylation pattern and expression of IL17RC may potentially serve as a biomarker for the diagnosis of AMD and likely plays a role in disease pathogenesis.

Anti-VEGF treatment in neovascular age-related macular degeneration: a treat-and-extend protocol over 2 years.

Purpose: To evaluate 2-year visual acuity outcome of a treat-and-extend protocol of anti–vascular endothelial growth factor treatment in age-related macular degeneration. Methods: In this prospective cohort study, 120 age-related macular degeneration patients with choroidal neovascularization received 3 initial monthly ranibizumab or bevacizumab injections; monthly injections were continued until there was no choroidal neovascularization activity (subretinal/intraretinal fluid, loss of >5 letters, or persistent/recurrent retinal hemorrhage). When there was no choroidal neovascularization activity, the interval to the next visit/injection was extended by 2 weeks to a maximum of 12 weeks. In the presence of choroidal neovascularization activity, this interval was shortened by 2 weeks. Main outcome measures included the percentage losing <15 letters and the mean visual acuity change after 12 months and 24 months. Results: Mean baseline visual acuity was 51.2 ± 12.1 Early Treatment Diabetic Retinopathy Study scores. Mean visual acuity change from baseline was +9.5 ± 10.9 and +8.0 ± 12.9 letters after 12 months and 24 months, respectively, with, on average, 8.6 ± 1.1 visits/injections in the first year and 5.6 ± 2.0 in the second year. After 12 months and 24 months, 97.5% and 95.0% of patients, respectively, lost <15 letters. Conclusion: The “inject-and-extend” protocol—with fewer injections and visits—delivered outcomes comparable to those of the pivotal clinical trials of monthly ranibizumab.