Incidence and Progression of Nongeographic Atrophy in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT) Clinical Trial

Gene and cell therapy for age-related macular degeneration: A review

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss among the elderly in Western communities, with an estimated global prevalence of 10 - 20% in people older than 65 years. AMD leads to central vision loss due to degeneration of the photoreceptors, retinal pigment epithelium and the choriocapillaris. Beckman's classification for AMD, based upon color fundus photographs, divides the disease into early, intermediate, and late forms. The late, vision-threatening stage includes both neovascular AMD and geographic atrophy. Despite its high prevalence and impact on patients' quality of life, treatment options for AMD are limited. While neovascular AMD can be medically managed with anti-VEGF intravitreal injections, until very recently there has been no approved treatment options for atrophic AMD; however, in February 2023 the first treatment for geographic atrophy - pegcetacoplan - was approved by the US FDA. We describe the current landscape of potential gene and cell therapeutic strategies for late-stage AMD, with an emphasis on the therapeutic options that might become available in the next few years.

Botulinum toxin type A in multimodal management of age-related macular degeneration and related diseases

Age related macular degeneration (AMD) is the major cause of visual loss in the aging population in the Western world. In past decade, intra ocular injections of anti-vascular endothelial growth factor (anti-VEGF) pharmaceuticals have revolutionized therapy for exudative (edematous-wet) AMD and become standard practice for the near term. However repeated intra-ocular injections are required for years and long terms results have been limited. The pathogenesis of this condition is multifactorial involving genetic, ischemic, inflammatory factors leading to neovascularization, edema and retinal pigment epithelial scaring resulting in photoreceptor destruction. Based on coincidental observation in reduction in AMD related macular edema on ocular coherence tomography (OCT) in a BoNT A treated patient with facial movement disease, BoNT-A at conventional doses targeting the para orbital area was added to therapeutic regiment in a small number of patients with exudative macular degeneration or related diseases. Measurements of edema and choriocapillaris using Spectral Doman (OCT) and Ocular Coherence Angiography (OCT-A) and Snellen visual acuity were made over the evaluation period. 15 eyes in 14 patients averaged 361 μm central sub foveal edema (CSFT) pre injection and average of 266 μm (CSFT) post injection over an average of 21 months and 5.7 cycles using BoNT A alone at conventional doses (n = 86 post injection measurements, paired t-test p < 0.001 two tailed). Visions at baseline in patients with 20/40 or worse averaged 20/100- pre injection improved to an average of 20/40- in the post injection period (n = 49 measurements p < 0.002 paired t-test). The previous data was added to a group of 12 more severely afflicted patients receiving anti VEGF (aflibercept or bevacizumab) (total 27 patients). With this 27-patient group, patients were followed for an average of 20 months and receiving average of 6 cycles at conventional doses. Improvement in exudative edema and vision were noted with pre injection baseline CSFT average 399.5, post injection average 267, n = 303 post measurement, independent t-test P < 0.0001.). Snellen vision 20/128 baseline average improved to average of 20/60- during post injection period (n = 157 post injection measurements, p < 0.0001 paired t-test to baseline). No substantial adverse effects were noted. Cyclic effects were noted corresponding to duration of action of BoNT-A on a number of patients. The above data is preliminary and is skewed toward early leakage for all conditions. BoNT A may have a role in the treatment of aged related macular degeneration. Controlled studies are needed with careful staging and baseline stratifications for multi-modal management paradigms. The findings are discussed relative to known botulinum toxin type A pharmacology and AMD pathogenesis.

Impact of Prophylactic Ranibizumab to Prevent Neovascular Age-Related Macular Degeneration on Eyes With Intermediate Age-Related Macular Degeneration

Purpose

The purpose of this study was to determine the impact of prophylactic ranibizumab (PR) injections given every 3 months in eyes with intermediate nonexudative age-related macular degeneration (AMD) on drusen volume, macular layer thicknesses, and progression of geographic atrophy (GA) area over 24 months in the PREVENT trial.

Methods

This post hoc analysis of the prospective PREVENT trial compared eyes with intermediate AMD randomized to PR versus sham injections to determine rates of conversion to neovascular AMD over 24 months. Drusen area and volume, macular thickness and volume, and retinal layer thicknesses were measured on spectral-domain optical coherence tomography images and analyzed. Masked grading of GA area and subretinal drusenoid deposits (SDDs) using fundus autofluorescence images was performed.

Results

There were no statistical differences in drusen area and volumes between groups, and similar reductions in central subfield thickness, mean cube thickness, cube volume, and retinal sublayer thickness from baseline to 24 months (P = 0.018 to < 0.001), with no statistical differences between groups in any of these anatomic parameters. These findings were not impacted by the presence or absence of SDD. Among the 9 eyes with GA in this study, mean GA growth rate from baseline to 24 months was 1.34 +/- 0.79 mm2/year after PR and 1.95 +/- 1.73 mm2/year in sham-treated eyes (P = 0.49), and similarly showed no statistical difference with square root transformation (P = 0.61).

Conclusions

Prophylactic ranibizumab given every 3 months did not appear to affect drusen volume, macular thinning, or GA progression in eyes with intermediate AMD.

Translational Relevance

This work investigates the impact of PR on progressive retinal degeneration in a clinical trial.

iPSC-RPE in Retinal Degeneration: Recent Advancements and Future Perspectives

Regenerative medicine is a great hope for patients suffering from diseases for which no effective treatment is available. With the creation of induced pluripotent stem cells (iPSCs) in 2006, research and development has accelerated expeditiously, reaching a practical stage worldwide. The iPSC-regenerative medicine in ophthalmology is one of the pioneers, which has kicked off clinical application ahead of other fields owing to its advantages. The clinical safety issues of iPSC-derived retinal pigment epithelial (iPSC-RPE) transplantation for exudative age-related macular degeneration have been addressed to a certain extent. Preparations are being made for the next clinical study based on the improvement of its therapeutic effects and expansion of indications globally. Steady progress toward the practical applications of regenerative medicine for the treatment of retinal disorders is expected in the future while strengthening global cooperation amid various research areas, clinical fields, and regulations.

Impact of intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell and nerve fibre layer thickness in Neovascular age‐related macular degeneration

PURPOSE

To compare the effects of monotherapy with intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell layer (RGCL) and retinal nerve fibre layer (RNFL) in patients with naïve neovascular age-related macular degeneration (nAMD).

METHODS

This is a retrospective cohort study with three-groups comparison. 83 patients and 97 eyes on continuous monotherapy with an intravitreal anti-vascular endothelial growth factor (anti-VEGF) were followed for 24 months and divided into three groups according to anti-VEGF (aflibercept: 25 eyes, ranibizumab: 34 eyes, bevacizumab: 38 eyes). Main outcome measures included: RGCL and RNFL thickness, best corrected visual acuity (BCVA), central macular thickness (CMT), macular volume (MV) and the presence of intraretinal fluids (IRF), subretinal fluids (SRF) and retinal pigment epithelial atrophy (RPE-atrophy). All outcome measures were recorded at the time of the first injection, 1 and 2 years after treatment and compared longitudinally and between groups.

RESULTS

The mean age was 79 ± 7 years. The RGCL thickness, MV, CMT and the presence of IRF and SRF decreased significantly within all three medication groups (p < 0.05 for all) with no significant difference between groups over the 2-year follow-up period (p > 0.10 for all). The decrease in RNFL thickness was not significant within or between the groups after a 2-year follow-up (p > 0.055 for all). RPE-atrophy increased significantly after 2 years in all three groups (p < 0.028 for all) with no significant difference between groups at all three time points (p > 0.307 for all). BCVA was comparable between the three groups over the 2-year follow-up period (p > 0.22 for all).

CONCLUSIONS

Monotherapy with intravitreal aflibercept, bevacizumab and ranibizumab was associated with comparable significant decreases in RGCL thickness, CMT, MV, IRF and SRF in naïve nAMD patients during the first 2 years of treatment. Furthermore, no significant differences either in BCVA or RNFL thickness were observed between the three intravitreal anti-VEFGs during the first 2 years of treatment.

Role of Erythropoietin Receptor Signaling in Macrophages or Choroidal Endothelial Cells in Choroidal Neovascularization

Erythropoietin (EPO) has been proposed to reduce the progression of atrophic age-related macular degeneration (AMD) due to its potential role in neuroprotection. However, overactive EPO receptor (EPOR) signaling increased laser-induced choroidal neovascularization (CNV) and choroidal macrophage number in non-lasered mice, which raised the question of whether EPOR signaling increased CNV through the recruitment of macrophages to the choroid that released pro-angiogenic factors or through direct angiogenic effects on endothelial cells. In this study, we addressed the hypothesis that EPOR signaling increased CNV by direct effects on macrophages or endothelial cells. We used tamoxifen-inducible macrophage-specific or endothelial cell-specific EPOR knockout mice in the laser-induced CNV model, and cultured choroidal endothelial cells isolated from adult human donors. We found that macrophage-specific knockout of EPOR influenced laser-induced CNV in females only, whereas endothelial-specific knockout of EPOR reduced laser-induced CNV in male mice only. In cultured human choroidal endothelial cells, knockdown of EPOR reduced EPO-induced signal transducer and activator of transcription 3 (STAT3) activation. Taken together, our findings suggest that EPOR signaling in macrophages or choroidal endothelial cells regulates the development of CNV in a sex-dependent manner. Further studies regarding the role of EPO-induced signaling are required to assess EPO safety and to select or develop appropriate therapeutic approaches.

Local Geographic Atrophy Growth Rates Not Influenced by Close Proximity to Non-Exudative Type 1 Macular Neovascularization

Purpose

The local growth rates of geographic atrophy (GA) adjacent to non-exudative type 1 macular neovascularization (MNV) were investigated to determine if MNV influenced GA growth.

Methods

Eyes with GA and non-exudative type 1 MNV were followed for at least 1 year. Both GA and the MNV were imaged and measured using swept-source optical coherence tomography angiography (SS-OCTA) scans. Pearson correlations were computed between local growth rates of GA, which were estimated using a biophysical GA growth model, and local distances-to-MNV. Corresponding P values for the null hypothesis of no Pearson correlation were computed using a Monte Carlo approach that adjusts for spatial autocorrelations.

Results

Nine eyes were included in this study. There were positive correlations (Pearson's r > 0) between distance-to-MNV and local GA growth in eight (89%) of the eyes; however, in all but one eye (11%), correlations were relatively weak and statistically nonsignificant after Bonferroni correction (corrected P > 0.05).

Conclusions

SS-OCTA imaging combined with GA growth modeling and spatial statistical analysis enabled quantitative assessment of correlations between local GA growth rates and local distances-to-MNV. Our results are not consistent with non-exudative type 1 MNV having a strong inhibitory effect on local GA growth rates.

MicroRNAs and the HIF/VEGF axis in ocular neovascular diseases

Ocular neovascular diseases, such as proliferative diabetic retinopathy, retinopathy of prematurity and neovascular age-related macular degeneration, are the leading causes of visual impairment worldwide. The hypoxia-inducible factors and vascular endothelial growth factors are key molecular promoters of ocular neovascularization. Moreover, the role of microRNAs as regulators of angiogenesis has been expanding, particularly hypoxia-associated microRNA; hypoxamiRs. This review provides a summary of hypoxamiRs that directly and specifically target HIF1A and VEGF mRNAs, thus critically involved in the regulation of ocular neovascular pathologies. The discussed microRNAs highlight putative diagnostic markers and therapeutic agents in choroidal and retinal angiogenic diseases, including proliferative diabetic retinopathy, retinopathy of prematurity and neovascular age-related macular degeneration.

The Development of Macular Atrophy in Patients with Wet Age-Related Macular Degeneration Receiving Anti-VEGF Treatment

Age-related macular degeneration (AMD) is a leading cause of blindness. Late AMD can be classified into exudative (commonly known as wet AMD [wAMD]) or dry AMD, both of which may progress to macular atrophy (MA). MA causes irreversible vision loss and currently has no approved pharmacological treatment. The standard of care for wAMD is treatment with anti-vascular endothelial growth factors (VEGF). However, recent evidence suggests that anti-VEGF treatment may play a role in the development of MA. Therefore, it is important to identify risk factors for the development of MA in patients with wAMD. For example, excessive blockade of VEGF through intense use of anti-VEGF agents may accelerate the development of MA. Patients with type III macular neovascularisation (retinal angiomatous proliferation) have a particularly high risk of MA. These patients are characterised as having a pre-existing thin choroid (age-related choroidopathy), suggesting that the choroidal circulation is unable to respond to increased VEGF expression. Evidence suggests that subretinal fluid (possibly indicative of residual VEGF activity) may play a protective role. Patients receiving anti-VEGF agents must be assessed for overall risk of MA and there is an unmet medical need to prevent the development of MA without undertreating wAMD.

Trends of Stem Cell Therapies in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a highly prevalent irreversible impairment in the elderly population worldwide. Stem cell therapies have been considered potentially viable for treating AMD through the direct replacement of degenerated cells or secretion of trophic factors that facilitate the survival of existing cells. Among them, the safety of pluripotent stem cell-derived retinal pigment epithelial (RPE) cell transplantation against AMD, and some hereditary retinal degenerative diseases, has been discussed to a certain extent in clinical studies of RPE cell transplantation. Preparations are in progress for its clinical application. On the other hand, clinical trials using somatic stem cells are also being conducted, though these had controversial outcomes. Retinal regenerative medicine using stem cells is expected to make steady progress toward practical use while new technologies are incorporated from various fields, thereby making the role of ophthalmologists in this field increasingly important.

Echinomycin mitigates ocular angiogenesis by transcriptional inhibition of the hypoxia-inducible factor-1

BACKGROUND

Echinomycin (EKN), an inhibitor of hypoxia-inducible factor (HIF)-1 DNA-binding activity, has been implied as a possible therapeutic agent in ischemic diseases. Here, we assess EKN in hypoxia-driven responses in vitro using human primary adult retinal pigment epithelium cells (aRPE) and retinal endothelial cells (hREC), and in vivo using the laser-induced mouse choroidal neovascularization (CNV) model.

METHODS

Effects of EKN on hypoxia-mediated pathways in aRPE were analyzed by Western blotting for HIF-1α protein, quantitative PCR of HIF-target genes, and proteome array for soluble angiogenic factors. In vitro inhibition of angiogenesis by EKN was determined in hREC. In vivo inhibition of angiogenesis by EKN was determined in the mouse laser-induced CNV, as a model of HIF-associated ocular neovascularization. CNV lesion area was determined by fundus fluorescein angiography.

RESULTS

aRPE treated with EKN showed hypoxia-dependent significantly decreased cell recovery in the wound healing assay. These results were supported by lower levels of HIF-mediated transcripts detected in hypoxic aRPE cells treated with EKN compared with non-treated controls, and confirmed by proteome profiler for angiogenic factors. hREC exposed to aRPE EKN-conditioned medium displayed reduced sprouting angiogenesis. Mice with laser-induced CNV treated with intravitreally injected EKN showed significantly decreased vascular lesion area when compared with a mouse equivalent of aflibercept, or vehicle-treated controls.

CONCLUSIONS

Our data proposes EKN as a potent inhibitor of HIF-mediated angiogenesis in retinal cells and in the mouse model of CNV, which could have future implications in the treatment of patients with neovascular age-related macular degeneration.

Natural history of incomplete retinal pigment epithelial and outer retinal atrophy in age-related macular degeneration

OBJECTIVE

To assess the time course and risk factors for conversion of incomplete retinal pigment epithelium and outer retina atrophy (iRORA) to complete retinal pigment epithelium and outer retina atrophy (cRORA) in eyes with non-neovascular intermediate age-related macular degeneration (iAMD), using optical coherence tomography (OCT) analysis.

DESIGN

Retrospective survival study.

PARTICIPANTS

Tracked structural Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) volume datasets from 2 retinal specialists at the University of California-Los Angeles were retrospectively screened to identify consecutive participants with non-neovascular iAMD without signs of atrophy or macular neovascularization in either eye at baseline.

METHODS

In the first stage of selection, 321 consecutive iAMD eyes were screened for onset of iRORA. Eyes that developed iRORA within the first 24 months were followed for an additional 24 months to assess the rate of conversion to cRORA. A Kaplan-Meier survival curve was formulated to illustrate the conversion from iRORA to cRORA.

RESULTS

Among 321 baseline participants with iAMD, 87 incident iRORA lesions (50 eyes, 42 participants) were included in the conversion analysis. Eighty-one iRORA lesions (93.1%) converted to cRORA within 24 months (median 14 months). Multivariate binary logistic regression analysis indicated that intraretinal hyperreflective foci and extrafoveal iRORA location at baseline were associated with a faster rate of progression to cRORA (model R² = 0.816, p < 0.05).

CONCLUSIONS

The majority of incident iRORA lesions progress to cRORA within a 24-month period. These findings may be of value in the design of early intervention trials for risk stratification and prognostication but need to be validated with a prospective analysis.

Long-Term Safety Evaluation of Continuous Intraocular Delivery of Aflibercept by the Intravitreal Gene Therapy Candidate ADVM-022 in Nonhuman Primates

Purpose

To evaluate the long-term safety of vascular endothelial growth factor (VEGF) suppression with sustained aflibercept expression after a single intravitreal injection (IVI) of ADVM-022, an anti-VEGF gene therapy, in non-human primates (NHPs).

Methods

Non-human primates received bilateral IVI of ADVM-022, a gene therapy vector encoding aflibercept, a standard of care for the treatment of VEGF-based retinal disease. Aflibercept levels from ocular fluids and tissues were measured. Ocular inflammation was assessed by slit lamp biomicroscopy and fundoscopy. The integrity of the retinal structure was analyzed by optical coherence tomography and blue light fundus autofluorescence and electroretinography was performed to determine retinal function. Histologic evaluation of the retina was performed at the longest time point measured (2.5 years after injection).

Results

Sustained expression of aflibercept was noted out to the last time point evaluated. Mild to moderate inflammatory responses were observed, which trended toward spontaneous resolution without anti-inflammatory treatment. No abnormalities in retinal structure or function were observed, as measured by optical coherence tomography and electroretinography, respectively. RPE integrity was maintained throughout the study; no histologic abnormalities were observed 2.5 years after ADVM-022 IVI.

Conclusions

In non-human primates, long-term, sustained aflibercept expression and the resulting continuous VEGF suppression by a single IVI of ADVM-022, appears to be safe, with no measurable adverse effects on normal retinal structure and function evaluated out to 2.5 years.

Translational Relevance

Together with the results from previous ADVM-022 preclinical studies, these data support the evaluation of this gene therapy candidate in clinical trials as a potential durable treatment for various VEGF-mediated ophthalmic disorders.