Pegcetacoplan for the treatment of geographic atrophy secondary to age-related macular degeneration (OAKS and DERBY): two multicentre, randomised, double-masked, sham-controlled, phase 3 trials

Complement-dependent neuroinflammation in spinal cord injury: from pathology to therapeutic implications

Spinal cord injury remains a major cause of disability in young adults, and beyond acute decompression and rehabilitation, there are no pharmacological treatments to limit the progression of injury and optimize recovery in this population. Following the thorough investigation of the complement system in triggering and propagating cerebral neuroinflammation, a similar role for complement in spinal neuroinflammation is a focus of ongoing research. In this work, we survey the current literature investigating the role of complement in spinal cord injury including the sources of complement proteins, triggers of complement activation, and role of effector functions in the pathology. We study relevant data demonstrating the different triggers of complement activation after spinal cord injury including direct binding to cellular debris, and or activation via antibody binding to damage-associated molecular patterns. Several effector functions of complement have been implicated in spinal cord injury, and we critically evaluate recent studies on the dual role of complement anaphylatoxins in spinal cord injury while emphasizing the lack of pathophysiological understanding of the role of opsonins in spinal cord injury. Following this pathophysiological review, we systematically review the different translational approaches used in preclinical models of spinal cord injury and discuss the challenges for future translation into human subjects. This review emphasizes the need for future studies to dissect the roles of different complement pathways in the pathology of spinal cord injury, to evaluate the phases of involvement of opsonins and anaphylatoxins, and to study the role of complement in white matter degeneration and regeneration using translational strategies to supplement genetic models.

Intravitreal therapy-success stories and challenges

Intravitreal injections have revolutionized the treatment of various sight-threatening diseases of the posterior segment of the eye. Initially explored for treatment of bacterial endophthalmitis, intravitreal injections rapidly expanded to combat retinal vascular disease in particular. Especially anti-vascular endothelial growth factor agents have emerged as a cornerstone of intravitreal therapy, targeting neovascular age-related macular degeneration and diabetic macular edema as important examples. Advances continue, with novel therapies such as complement inhibitors now available as treatment for geographic atrophy secondary to non-neovascular age-related macular degeneration, offering hope for a previously untreatable condition. Pioneering approaches such as the port delivery system and intravitreal gene therapy aim to improve treatment efficacy while minimizing patient burden. Despite notable successes, challenges for intravitreal therapies persist, including ocular and systemic complications and high treatment burden. Future research endeavors aim to address these challenges and enhance treatment outcomes. This comprehensive review critically evaluates the efficacy, safety, and cost-effectiveness of intravitreal injections, delving into emerging trends and future directions.

Utilisation of patient-centred outcome measures in age-related macular degeneration research and clinical practice: A systematic review

BACKGROUND

To identify the utilisation, type, and psychometric properties of patient-centered outcome measures (PCOMs) associated with the performance-based assessment of visual function (VF) in age-related macular degeneration (AMD) in clinical care and research.

METHODS

A systematic literature search identified studies, available in English, that used PCOMs to assess VF in patients with any AMD severity, published from January 2015 to November 2023. Two researchers screened studies for quality using the Mixed Methods Appraisal Tool (MMAT) 2018 and assessed the psychometric properties of the PCOMs with the guidance of Consensus-based Standards for the selection of health Measurement Instruments (COSMIN).

RESULTS

Of 514 studies shortlisted in the literature, 31 were eligible with the majority (77.4%) fulfilling all the MMAT criteria, indicating good quality. The most used PCOM was reading (14/31 = 45.1%), with 5 of the 14 studies (35.7%) showing that the increasing severity and/or progression of AMD were associated with a worsening reading ability. AMD also negatively affected mobility and physical activity levels (7/31 = 22.6%), and visual search and exploration (4/31 = 12.9%). Based on the COSMIN checklist, apart from reading and physical activity measured with the accelerometer, the other PCOMs had 'inadequate' psychometric properties.

CONCLUSIONS

Limited published studies include PCOMs as an assessment of VF in AMD patients. Apart from reading, there is a lack of robust validation data to support the widespread use of other PCOMs. Hence, well-designed, robustly validated, and simple to use PCOMs are required for more widespread implementation in AMD clinical care and research.

Population Pharmacokinetics of Pegcetacoplan in Patients with Geographic Atrophy or Neovascular Age-related Macular Degeneration

Objective

To develop a population pharmacokinetic (PK) model to characterize serum pegcetacoplan concentration-time data after intravitreal administration in patients with geographic atrophy (GA) or neovascular age-related macular degeneration (nAMD).

Design

Pharmacokinetic modeling.

Participants

Two hundred sixty-one patients with GA or nAMD enrolled in 4 clinical studies of pegcetacoplan.

Methods

Serum concentration data were pooled from 4 clinical studies. Pegcetacoplan dosing included single intravitreal injections of 4, 10, and 20 mg and multiple intravitreal injections of 15 mg monthly or every other month. Considering a high proportion of samples were below the limit of quantification (BLQ) in serum following intravitreal administration, the M3 method of likelihood-based handling of data BLQ was employed in NONMEM (version 7.4). Covariate model development was performed using stepwise forward (α = 0.05) and backward (α = 0.001) selection. Predicted PK parameters and exposure metrics were generated via simulation in serum and vitreous humor.

Main Outcome Measures

Pharmacokinetic parameters.

Results

Intravitreal pegcetacoplan displayed absorption-limited (i.e., "flip-flop") kinetics with median empirical Bayes estimated pegcetacoplan absorption and elimination half-lives of 13.1 days and 4.51 days, respectively. Vitreous exposure was predicted to be >1300-fold higher than serum exposure, with maximum concentrations in serum below the threshold required to elicit systemic pharmacodynamic effects. Drug accumulation from first dose to steady state was predicted to be minimal in serum (mean accumulation ratio = 1.50 with monthly dosing, 1.10 with every-other-month dosing) and vitreous humor (mean accumulation ratio = 1.30 with monthly dosing, 1.10 with every-other-month dosing). Age, sex, and baseline C3 level were identified as significant (P < 0.001) predictors of apparent serum pegcetacoplan clearance after intravitreal administration; however, none of the covariate effects appeared to be clinically meaningful given the low absolute maximum serum concentrations achieved (<5 μg/mL). Concomitant anti-VEGF treatment did not significantly influence vitreous disposition of pegcetacoplan as assessed in a dedicated post hoc covariate model.

Conclusions

This population PK model adequately described the serum concentration-time profile of pegcetacoplan after intravitreal administration in adults with GA or nAMD.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Repeatability of Microperimetry in Areas of Retinal Pigment Epithelium and Photoreceptor Loss in Geographic Atrophy Supported by Artificial Intelligence-Based Optical Coherence Tomography Biomarker Quantification

PURPOSE

Growing interest in microperimetry (MP) or fundus-controlled perimetry as a targeted psychometric testing method in geographic atrophy (GA) is warranted because of the disease subclinical/extrafoveal appearance or preexisting foveal loss with visual acuity becoming unreliable. We provide comprehensive pointwise test-retest repeatability reference values on the most widely used MP devices and combine them with targeted testing in areas of retinal pigment epithelium (RPE) as well as photoreceptor (PR) integrity loss, guiding the interpretation of sensitivity loss during the long-term follow-up of patients with GA.

DESIGN

Prospective reliability study.

METHODS

Patients with GA underwent consecutive testing on CenterVue (iCare) MAIA and NIDEK MP3 devices. Obtained pointwise sensitivity (PWS) measurements were spatially coregistered to an optical coherence tomography volume scan acquired during the same visit. Areas with RPE and PR integrity loss, drusen, and PR thickness as well as the volume of hyperreflective foci where identified and quantified using a set of validated deep learning-based algorithms. Test-retest repeatability was assessed according to areas defined by biomarker-specific morphologic changes using Bland-Altmann coefficients of repeatability. Furthermore, the interdevice correlation, the repeatability of scotoma point detection, and any potential effects on fixation stability were assessed.

RESULTS

Nine hundred stimuli per device from 20 subjects were included. Identical overall PWS test-retest variance could be detected for MAIA (±6.57) and MP3 (±6.59). PR integrity loss was associated with a higher test-retest variance on both devices (MAIA, P = .002; MP3, P < .001). Higher coefficients of repeatability for stimuli in areas presenting RPE loss (±10.99 vs ±5.34) or hyperreflective foci (±9.21 vs ±6.25) could only be detected on MP3 examinations (P < .001 and P = .01, respectively). An excellent intradevice correlation (MAIA 0.94 [0.93-0.95], MP3 0.94 [0.94-0.95]) and a good mean interdevice correlation (0.84 [0.53-0.92]) were demonstrated. The chosen device, run order, or absence of foveal sparing had no significant effect on fixation stability.

CONCLUSION

Areas presenting automatically quantified PR integrity loss with and without underlying RPE loss are associated with higher test-retest variance for both MAIA and MP3. These findings are crucial for an accurate interpretation of GA progression during long-term follow-up and the planning of future trials with MP testing as functional study endpoint.

Latest trends & strategies in ocular drug delivery

Ocular drug delivery is one of the most challenging routes of administration, and this may be attributed to the complex interplay of ocular barriers and clearance mechanisms that restrict therapeutic payload residence. Most of the currently approved products that ameliorate ocular disease conditions are topical, i.e., delivering therapeutics to the outside anterior segment of the eye. This site of administration works well for certain conditions such as local infections but due to the presence of numerous ocular barriers, the permeation of therapeutics to the posterior segment of the eye is limited. Conditions such as age-related macular degeneration and diabetic retinopathy that contribute to an extreme deterioration of vision acuity require therapeutic interventions at the posterior segment of the eye. This necessitates development of intraocular delivery systems such as intravitreal injections, implants, and specialized devices that deliver therapeutics to the posterior segment of the eye. Frequent dosing regimens and high concentration formulations have been strategized and developed to achieve desired therapeutic outcomes by overcoming some of the challenges of drug clearance and efficacy. Correspondingly, development of suitable delivery platforms such as biodegradable and non-biodegradable implants, nano delivery systems, and implantable devices have been explored. This article provides an overview of the current trends in the development of suitable formulations & delivery systems for ocular drug delivery with an emphasis on late-stage clinical and approved product. Moreover, this work aims to summarize current challenges and highlights exciting pre-clinical developments, and future opportunities in cell and gene therapies that may be explored for effective ocular therapeutic outcomes.

Pentosan Polysulfate Maculopathy: Final Outcomes from a 4-Year Prospective Study of Disease Progression after Drug Cessation

PURPOSE

To report the long-term disease course of pentosan polysulfate (PPS) maculopathy following drug cessation.

DESIGN

Single-institution, prospective case series.

METHODS

23 eyes of 12 participants seen at the Emory Eye Center with a diagnosis of PPS maculopathy were included in our study. Participants were enrolled between December 1, 2018, and December 1, 2019, and data were collected annually for four years.

MAIN OUTCOMES AND MEASURES

Changes in visual function and retinal structure were the primary outcomes measured. Visual function was assessed using Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA), ETDRS low-luminance visual acuity (LLVA), Minnesota low-vision reading (MNREAD) performance, contrast sensitivity, mesopic and scotopic microperimetry, and dark adaptometry. Patient reported outcomes were assessed with the National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) and Low Luminance Questionnaire (LLQ). Structural outcomes included the presence of complete retinal pigment epithelium and outer retinal atrophy (cRORA), atrophic lesion size (in mm2), macular central subfield thickness (CST), and subfoveal choroidal thickness (SFCT).

RESULTS

Of the 12 participants, 11 (91.7%) were female, with a median age at enrollment of 58 years. The median ETDRS BCVA letter score at baseline was 83, with a median change of -5 letters over 4 years (P = 0.005). The median 4-year change in mesopic microperimetry average threshold and percent reduced threshold was -5.4 dB (P = 0.003) and 48.6% (P = 0.004), respectively. MNREAD performance (assessed at 2 and 4 years) declined across all measures, with a median maximum reading speed change of -21 words per minute (P = 0.007). NEI-VFQ-39 and LLQ composite scores significantly decreased over 4 years. At baseline, 9 eyes (39%) had macular cRORA. By the study's end, 5 of the remaining eyes (35.7%) developed new-onset cRORA. The median linearized growth rate of atrophic lesions was 0.23 mm/year. The median 4-year change of CST and SFCT was -7.0 µm (P = 0.055) and -22.0 µm (P = 0.610), respectively.

CONCLUSION

This prospective study demonstrates continued progression of broad-ranging functional and structural deficits in PPS maculopathy long after drug cessation. These findings should inform PPS prescribing patterns, patient counseling, and disease monitoring strategies.

Development of self-healing hydrogels to support choroidal endothelial cell transplantation for the treatment of early age related macular degeneration

In retinal diseases such as age-related macular degeneration (AMD) and choroideremia, a key pathophysiologic step is loss of endothelial cells of the choriocapillaris. Repopulation of choroidal vasculature early in the disease process may halt disease progression. Prior studies have shown that injection of donor cells in suspension results in significant cellular efflux and poor cell survival. As such, the goal of this study was to develop a hydrogel system designed to support choroidal endothelial cell transplantation. A library of hydrogels was synthesized using laminin (i.e., LN111, LN121, and LN421), carboxy methyl chitosan, and oxidized dextran via reversible Schiff base chemistry. Each of the developed self-healing hydrogels was readily injectable into the suprachoroidal space, with ideal gelation, mechanical, and degradation properties. While all hydrogels were found to be compatible with choroidal endothelial cell survival in vitro, only LN111 and LN121 gels were well-tolerated in vivo. To determine if hydrogel mediated cell delivery enhances donor cell retention and survival in vivo, iPSC-derived choroidal endothelial cell laden hydrogels were injected into the suprachoroidal space of an immunocompromised choroidal cell injury rat model. Significantly more donor cells were retained and survived in eyes that received cell laden hydrogels versus contralateral hydrogel free controls. Furthermore, donor cells positive for human nuclear antigen were identified in the choroid of hydrogel eyes only. These findings pave the way for future cell replacement studies in large animal models of choroidal cell dropout focused on evaluating functional integration of donor cells within decellularized vascular tubes. STATEMENT OF SIGNIFICANCE: Age related macular degeneration (AMD) is a leading cause of untreatable blindness in the industrial world. A key pathologic step in AMD is loss of the choriocapillaris endothelial cells, which provide vascular support to the overlying retina. Choroidal cell replacement early in disease may prevent retinal cell death and subsequent vision loss. In this study, we present a strategy for repopulating the choriocapillaris using choroidal endothelial cell laden hydrogels. Specifically, we demonstrate the synthesis and characterization of 3 different laminin-based hydrogel systems. LN111 and LN121 hydrogels were found to have excellent biocompatibility both in vitro and in vivo. Hydrogel mediated delivery of iPSC-derived choroidal endothelial cells enhanced donor cell retention and survival, paving the way for functional large animal studies.

Could Infectious Agents Play a Role in the Onset of Age-related Macular Degeneration? A Scoping Review

Topic

This scoping review aims to summarize the current state of knowledge on the potential involvement of infections in age-related macular degeneration (AMD).

Clinical relevance

Age-related macular degeneration is a multifactorial disease and the leading cause of vision loss among older adults in developed countries. Clarifying whether certain infections participate in its onset or progression seems essential, given the potential implications for treatment and prevention.

Methods

Using the PubMed database, we searched for articles in English, published until June 1, 2023, whose title and/or abstract contained terms related to AMD and infections. All types of study design, infectious agents, AMD diagnostic methods, and AMD stages were considered. Articles dealing with the oral and gut microbiota were not included but we provide a brief summary of high-quality literature reviews recently published on the subject.

Results

Two investigators independently screened the 868 articles obtained by our algorithm and the reference lists of selected studies. In total, 40 articles were included, among which 30 on human data, 9 animal studies, 6 in vitro experiments, and 1 hypothesis paper (sometimes with several data types in the same article). Of these, 27 studies were published after 2010, highlighting a growing interest in recent years. A wide range of infectious agents has been investigated, including various microbiota (nasal, pharyngeal), 8 bacteria, 6 viral species, and 1 yeast. Among them, most have been investigated anecdotally. Only Chlamydia pneumoniae, Cytomegalovirus, and hepatitis B virus received more attention with 17, 6, and 4 studies, respectively. Numerous potential pathophysiological mechanisms have been discussed, including (1) an indirect role of infectious agents (i.e. a role of infections located distant from the eye, mainly through their interactions with the immune system) and (2) a direct role of some infectious agents implying potential infection of various cells types within AMD-related tissues.

Conclusions

Overall, this review highlights the diversity of possible interactions between infectious agents and AMD and suggests avenues of research to enrich the data currently available, which provide an insufficient level of evidence to conclude whether or not infectious agents are involved in this pathology.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Artificial intelligence in managing retinal disease-current concepts and relevant aspects for health care providers

Given how the diagnosis and management of many ocular and, most specifically, retinal diseases heavily rely on various imaging modalities, the introduction of artificial intelligence (AI) into this field has been a logical, inevitable, and successful development in recent decades. The field of retinal diseases has practically become a showcase for the use of AI in medicine. In this article, after providing a short overview of the most relevant retinal diseases and their socioeconomic impact, we highlight various aspects of how AI can be applied in research, diagnosis, and disease management and how this is expected to alter patient flows, affecting also health care professionals beyond ophthalmologists.

Gender and ethnic diversity in randomised clinical trials in age-related macular degeneration and diabetic macular oedema

In recent years, there has been increasing recognition of the importance of diversity in pivotal randomised clinical trials (RCTs). This is vital to ensure the validity and applicability of the results in the clinical setting. In this review, we aim to assess the inclusion of females and minoritized groups in recent RCTs in age-related macular degeneration (AMD) and diabetic macular oedema (DMO) and explore any potential barriers to their enrolment. Overall, a female predominance was observed among the AMD RCTs while less than half of the study population in DMO trials were females. White participants made up the majority of the study population in both AMD and DMO trials. Gender distribution within minoritized groups has only been reported in a few trials but appears lower than in the white population. This disparity may be attributable to the difference in the prevalence of diseases between these subgroups, as well as social and/ or cultural reasons. Nonetheless, there has been an overall increase in representation of minoritized groups over the past two decades. These observations provide important perspectives to consider when applying clinical trial learnings to clinical settings.

Visual Function Benefit After Treatment With Pegcetacoplan: Microperimetry Analysis From The Phase 3 Oaks Trial: Microperimetry: Visual Function Benefit With Pegcetacoplan

PURPOSE

To evaluate the impact of pegcetacoplan on its ability to slow the loss of visual function using microperimetry endpoints in eyes with geographic atrophy secondary to age-related macular degeneration (AMD).

DESIGN

Post hoc analysis of phase 3 randomized controlled trial data.

METHODS

Utilizing data from the OAKS study, which evaluated pegcetacoplan monthly (PM) or every other month (PEOM) versus sham for the treatment of GA secondary to AMD, microperimetry endpoints were assessed at baseline and every 6 months until 24 months, using a 10-2 grid composed of 68 points with a 4-2 threshold strategy. Main outcome measures included the time to development of absolute scotomas in the 4 and 16 central macular points. The number of absolute scotomatous points and mean retinal sensitivity (dB) within the junctional zone extending to 250 µm on either side of autofluorescence-determined GA border was analyzed for change from baseline.

RESULTS

Among 605 patients with subfoveal or nonsubfoveal GA, treatment with pegcetacoplan delayed time to development of absolute scotomas of all 4 central macular points compared to sham at 24 months (PM: hazard ratio [HR]: 0.66 [34% risk reduction]; 95% confidence interval [CI]: 0.46, 0.96; p = 0.0282; PEOM: HR: 0.64 [36% risk reduction]; 95% CI: 0.44, 0.92; p = 0.0164). Similarly, PM and PEOM treatment delayed time to development of absolute scotomas of all 16 central points (PM: HR: 0.57 [43% risk reduction]; 95% CI: 0.33, 0.96; p = 0.0361; PEOM: HR: 0.52 [48% risk reduction]; 95% CI: 0.32, 0.85; p = 0.0084). Across the junctional zone of GA, pegcetacoplan-treated eyes developed fewer absolute scotomatous points (PM difference vs sham pooled: -0.68 points, p = 0.1444; PEOM difference vs sham pooled: -1.14 points, p = 0.0140) and experienced decreased loss of mean retinal sensitivity (PM difference vs sham pooled: 0.56 dB, p = 0.0650; PEOM difference vs sham pooled: 0.71 dB, p = 0.0202) compared with sham at 24 months.

CONCLUSIONS

Microperimetry demonstrates a reduced rate of visual function loss in the central macula and junctional zone with pegcetacoplan treatment in GA due to AMD.

Sigma-2 receptor modulator CT1812 alters key pathways and rescues retinal pigment epithelium (RPE) functional deficits associated with dry age-related macular degeneration (AMD)

Trafficking defects in retinal pigmented epithelial (RPE) cells contribute to RPE atrophy, a hallmark of geographic atrophy (GA) in dry age-related macular degeneration (AMD). Dry AMD pathogenesis is multifactorial, including amyloid-β (Aβ) accumulation and oxidative stress-common features of Alzheimer's disease (AD). The Sigma-2 receptor (S2R) regulates lipid and protein trafficking, and S2R modulators reverse trafficking deficits in neurodegeneration in vitro models. Given overlapping mechanisms contributing to AD and AMD, S2R modulator effects on RPE function were investigated. The S2R modulator CT1812 is in clinical trials for AD, dementia with Lewy bodies, and GA. Leveraging AD trials testing CT1812, unbiased analyses of patient biofluid proteomes revealed that proteins altered by CT1812 associated with GA and macular degeneration disease ontologies and overlapped with proteins altered in dry AMD. Differential expression analysis of RPE transcripts from APP-Swedish/London mutant transgenic mice, a model featuring Aβ accumulation, revealed reversal of autophagy/trafficking transcripts in S2R modulator-treated animals versus vehicle toward healthy control levels. Photoreceptor outer segment (POS) trafficking in human RPE cells showed deficits in response to Aβ1-42 or hydrogen peroxide compared to vehicle. S2R modulators normalized stressor-induced POS trafficking deficits, resembling healthy control. Taken together, S2R modulation may provide a novel therapeutic strategy for dry AMD.

Modeling pegcetacoplan treatment effect for atrophic age-related macular degeneration with AI-based progression prediction

BACKGROUND

To illustrate the treatment effect of Pegcetacoplan for atrophy secondary to age-related macular degeneration (AMD), on an individualized topographic progression prediction basis, using a deep learning model.

METHODS

Patients (N = 99) with atrophy secondary to AMD with longitudinal optical coherence tomography (OCT) data were retrospectively analyzed. We used a previously published deep-learning-based atrophy progression prediction algorithm to predict the 2-year atrophy progression, including the topographic likelihood of future retinal pigment epithelial and outer retinal atrophy (RORA), according to the baseline OCT input. The algorithm output was a step-less individualized topographic modeling of the RORA growth, allowing for illustrating the progression line corresponding to an 80% growth compared to the natural course of 100% growth.

RESULTS

The treatment effect of Pegcetacoplan was illustrated as the line when 80% of the growth is reached in this continuous model. Besides the well-known variability of atrophy growth rate, our results showed unequal growth according to the fundus location. It became evident that this difference is of potential functional interest for patient outcomes.

CONCLUSIONS

This model based on an 80% growth of RORA after two years illustrates the variable effect of treatment with Pegcetacoplan according to the individual situation, supporting personalized medical care.

Determinants of Four-Year Visual Acuity Loss in Geographic Atrophy - An Analysis of AREDS and AREDS2

PURPOSE

To investigate the relationship between geographic atrophy (GA) progression and change in best-corrected visual acuity (BCVA) over 4 years and to identify factors associated with faster BCVA loss.

DESIGN

Secondary analysis of 2 randomized controlled clinical trials.

PARTICIPANTS

Age-Related Eye Diseases Study (AREDS) and AREDS2 participants with GA secondary to nonexudative age-related macular degeneration.

METHODS

Baseline and annual color fundus photographs were assessed for GA area and proximity to the foveal center. BCVA was measured using Early Treatment Diabetic Retinopathy Study logMAR charts. Analyses included BCVA change over 4 years, with the relationship of BCVA decline with GA progression and other baseline factors examined using multivariable linear mixed-effects models.

MAIN OUTCOME MEASURES

The primary outcome was BCVA change over 4 years. Secondary outcomes included BCVA change from baseline to years 1, 2, and 3.

RESULTS

We included 1351 eyes from 994 participants, including 594 eyes from 464 participants with 4-year BCVA follow-up. Higher baseline BCVA, smaller baseline GA proximity to the foveal center, and greater GA growth rate were each independently associated with larger BCVA loss over 4 years (each P < 0.001). Among the 594 eyes with 4-year BCVA data, 69 eyes with a baseline BCVA < 40 letters (Snellen equivalent of 20/160 or worse) and 42 eyes with baseline GA located more than 1 mm from the foveal center did not experience significant BCVA loss over 4 years. In contrast, 483 eyes that met both criteria of baseline BCVA ≥ 40 letters and GA lesions involving or within 1 mm of the foveal center showed significant BCVA loss over 4 years (mean change = -11.33 letters [95% confidence interval = -12.80 to -9.84]), with faster GA progression associated with larger BCVA loss (P < 0.001).

CONCLUSIONS

In this cohort, eyes with GA involving or within 1 mm of the foveal center and a baseline BCVA of ≥ 40 letters appeared more likely to experience significant BCVA loss, suggesting these eyes may benefit more from therapies that slow GA progression. Our findings support a personalized approach to managing GA patients, potentially guiding the design of future GA trials.

Validating candidate endpoints for intermediate age-related macular degeneration trials in a multi-centre setting-lessons from the MACUSTAR study

For the conduct of future interventional age-related macular degeneration (AMD) trials, the availability of clinical study endpoints is key. However, no endpoints have been accepted by regulators for evaluation of treatment for intermediate (i) AMD, i.e. the AMD stage at highest risk of developing irreversible geographic atrophy or macular neovascularization. The European MACUSTAR consortium has recruited more than 700 individuals to develop and validate structural, functional and patient-reported endpoints, enabling future iAMD trials based on a prospective observational, multi-centre cohort study. Reliably assessing candidate endpoints in a setting that involves multiple clinical sites across countries comes with a plurality of challenges in the study set-up, quality of data, recruitment of participants and study conduct. Therefore, the MACUSTAR consortium has established a framework that successfully addresses these topics, provides relevant insights into the natural history of iAMD and its sub-phenotypes, and will open new regulatory pathways. The MACUSTAR study is registered on ClinicalTrials.gov under NCT03349801.

Structure-Function Relationships in Geographic Atrophy Based on Mesopic Microperimetry, Fundus Autofluorescence, and Optical Coherence Tomography

Purpose

To examine relationships between retinal structure and visual function in geographic atrophy (GA) by analyzing spatial agreement between absolute scotomas and macular structure, focusing on (1) choroidal hypertransmission, a key feature of complete retinal pigment epithelium and outer retinal atrophy (cRORA), and (2) fundus autofluorescence (FAF)-defined GA.

Methods

Mesopic microperimetry (using a novel T-shaped pattern) and multimodal imaging were recorded longitudinally in a phase II GA trial. Horizontal and vertical optical coherence tomography (OCT) line scans (corresponding to the T axes) were graded for choroidal hypertransmission; FAF images were graded for GA. Spatial concordance between zones of absolute scotoma and atrophy was quantified by the Dice similarity coefficient (DSC).

Results

The analysis population comprised 24 participants (mean follow-up 26.8 months). For concordance between absolute scotoma and choroidal hypertransmission, estimated mean DSC was 0.70 (95% confidence interval [CI], 0.64-0.77). This was significantly higher than for FAF-defined GA (0.67; 95% CI, 0.61-0.74; estimated mean difference = 0.03, 95% CI, 0.02-0.05, P < 0.001). Mean OCT choroidal reflectivity was strongly associated with likelihood and severity of scotoma.

Conclusions

Spatial concordance between absolute scotomas and GA structural features is moderately high and slightly higher for choroidal hypertransmission than FAF-defined GA. This supports choroidal hypertransmission, a key cRORA feature, as an outcome measure in interventional trials. OCT provides more information to explain visual function than FAF alone. However, given some discordance for both structural features, performing microperimetry alongside imaging remains important.

Translational Relevance

These findings provide insights into the complex relationship between retinal structure and visual function and contribute to a nuanced understanding of outcome measures.

Insights into eye genetics and recent advances in ocular gene therapy

The rapid advancements in the field of genetics have significantly propelled the development of gene therapies, paving the way for innovative treatments of various hereditary disorders. This review focuses on the genetics of ophthalmologic conditions, highlighting the currently approved ophthalmic gene therapy and exploring emerging therapeutic strategies under development. Inherited retinal dystrophies represent a heterogeneous group of genetic disorders that manifest across a broad spectrum from infancy to late middle age. Key clinical features include nyctalopia (night blindness), constriction of the visual field, impairments in color perception, reduced central visual acuity, and rapid eye movements. Recent technological advancements, such as multimodal imaging, psychophysical assessments, and electrophysiological testing, have greatly enhanced our ability to understand disease progression and establish genotype-phenotype correlations. Additionally, the integration of molecular diagnostics into clinical practice is revolutionizing patient stratification and the design of targeted interventions, underscoring the transformative potential of personalized medicine in ophthalmology. The review also covers the challenges and opportunities in developing gene therapies for other ophthalmic conditions, such as age-related macular degeneration and optic neuropathies. We discuss the viral and non-viral vector systems used in ocular gene therapy, highlighting their advantages and limitations. Additionally, we explore the potential of emerging technologies like CRISPR/Cas9 in treating genetic eye diseases. We briefly address the regulatory landscape, concerns, challenges, and future directions of gene therapy in ophthalmology. We emphasize the need for long-term safety and efficacy data as these innovative treatments move from bench to bedside.

Outer Retinal Tubulation and Vision in Geographic Atrophy: A Natural History Analysis From the Phase 3 OAKS and DERBY Trials

BACKGROUND AND OBJECTIVE

Outer retinal tubulation (ORT) is an optical coherence tomography finding in numerous chronic retinal diseases, including geographic atrophy (GA). The objective of this study was to evaluate longitudinal best-corrected visual acuity (BCVA) outcomes in patients with GA comparing eyes with and without ORT at baseline.

PATIENTS AND METHODS

This post hoc longitudinal analysis assessed 300 eyes randomized to sham treatment in the phase 3 OAKS and DERBY trials. Mean change in BCVA over 24 months was calculated, comparing lesions with ORT versus those without ORT at baseline.

RESULTS

Ninety-six (32.0%) of the 300 sham-treated eyes with GA had an ORT at baseline. Eyes with ORT at baseline lost on average 5.5 fewer Early Treatment Diabetic Retinopathy Study letters than eyes without ORT.

CONCLUSION

Sham-treated eyes with ORT at baseline had less loss of BCVA over 24 months than eyes without ORT. [Ophthalmic Surg Lasers Imaging Retina 2025;56:XX-XX.].

Age-related macular degeneration: natural history revisited in geographic atrophy

Progression of geographic atrophy varies significantly based on individual and lesion characteristics. Much research has strived to understand prognostic indicators of lesion progression over time, yet integrating findings to date may pose a challenge to clinicians. This review strives to synthesize current knowledge on genetic, behavioral, structural, and functional factors that influence geographic atrophy across the lifetime. Further, it highlights how vision-related quality of life allows for a more holistic appraisal of the impact of geographic atrophy on everyday functioning. The ultimate aim of this paper is to aid clinicians in counseling patients on medical management as well as providing accurate disease prognostication tailored to the individual patient.

Pharmacokinetic/pharmacodynamic analysis of geographic atrophy lesion area in patients receiving pegcetacoplan treatment or sham

Pegcetacoplan is a complement C3/C3b inhibitor indicated for the treatment of geographic atrophy (GA). A population pharmacokinetic (PK)/pharmacodynamic (PD) analysis of pegcetacoplan used GA lesion area measurements from three clinical studies to determine the effect of pegcetacoplan exposure on GA progression. A base disease progression model was developed using data from sham-treated eyes and untreated fellow eyes, followed by treatment effect assessment in dose-response and PK/PD models. In total, 1501 patients from FILLY (NCT02503332), OAKS (NCT03525613), and DERBY (NCT03525600) received intravitreal pegcetacoplan 15 mg monthly or every other month (EOM) or sham treatment monthly or EOM and were included in the population analysis of lesion area. Disease progression over time was adequately described as linear-with-time over the 24-month maximal study duration. Disease-specific covariates associated with slower lesion growth were unilateral, unifocal, and subfoveal GA lesions and >20 intermediate or large drusen groups (≥63 μm) at baseline. The dose-response model estimated 0.80-fold (95% CI: 0.75, 0.84) and 0.83-fold (95% CI: 0.78, 0.87) reductions in GA lesion growth rate with pegcetacoplan monthly and EOM, respectively, versus sham. A relationship between vitreous humor concentration and GA lesion growth rate was quantified as 2.6% per unit of log-transformed vitreous pegcetacoplan concentration in the PK/PD model. PK/PD predictions of treatment effect based on exposure (pegcetacoplan monthly: 0.80 [90% CI: 0.77, 0.84]; pegcetacoplan EOM: 0.83 [90% CI: 0.80, 0.86]) were consistent with predictions based on dose response. These results support the benefit of pegcetacoplan administered monthly or EOM in slowing GA lesion growth.

Gene therapy for geographic atrophy in age-related macular degeneration: current insights

Geographic atrophy (GA) is the advanced stage of non-neovascular (dry) age-related macular degeneration, defined by the presence of sharply demarcated atrophic lesions of the outer retina. The complement system is integral to the body's natural immune response, and hence its overactivation can lead to tissue damage and inflammation. It has been shown to play a significant role in GA lesion development and progression, and therefore, complement inhibition is emerging as a promising avenue for therapeutic intervention. With the recent approval by the Food and Drug Administration of drugs like SYFOVRE™ (pegcetacoplan injection) and IZERVAY™ (avacincaptad pegol intravitreal solution), there is hope for the development of interventions capable of slowing down or arresting the progression of GA. In particular, gene therapy intervention is gaining traction for halting GA atrophy at the source of our genes. The concept is to insert a gene into the eye that will act as an ocular "bio-factory," producing a desired protein. This can either lead to overproduction of an already available protein or produce a substance not typically generated in the eye. This review aims to provide an overview of the present understanding of GA, encompassing risk factors, prevalence, pathophysiology, and genetic associations. It will also highlight the current landscape of GA treatment, with particular emphasis on gene therapy intervention.

Edridge Green Lecture 2022-demystifying clinical trials and regulatory approvals in drug development

This article provides a comprehensive overview of clinical trial design and regulatory pathways essential for drug development, specifically in the context of retinal diseases. Key concepts include trial structure, efficacy and safety endpoints, and regulatory expectations from agencies like the FDA. It delves into recent regulatory advancements, such as the inclusion of low-luminance vision as a secondary endpoint and analyses case studies from age-related macular degeneration (AMD) trials. Approvals for key retinal drugs, such as ranibizumab and aflibercept, treatments for AMD and diabetic macular oedema, are discussed highlighting criteria like the 15-letter gain/loss in visual acuity as approvable/clinical meaningful efficacy endpoints. Insights into geographic atrophy (GA) and diabetic retinopathy trials showcase the evolving landscape, where anatomical endpoints and new drugs bring fresh challenges and opportunities. It also emphasizes the importance of academic-industry collaboration, citing instances of gene therapy development and innovative endpoint measures like the Multi-Luminance Mobility Test for retinal dystrophies. The overarching aim of this lecture was to demystify the process that spans the design of clinical trials to regulatory approval of drugs so that clinicians understand these complexities. In particular, it is important to understand the reasons behind selection of trial design, inclusion and exclusion criteria, primary and secondary efficacy endpoints and safety endpoints. Since this lecture, there have been important changes in this field including new guidance from the Food and Drug Administration (FDA) as well as lessons learnt from recent drug approvals that are included in this manuscript.

Artificial intelligence in assessing progression of age-related macular degeneration

The human population is steadily growing with increased life expectancy, impacting the prevalence of age-dependent diseases, including age-related macular degeneration (AMD). Health care systems are confronted with an increasing burden with rising patient numbers accompanied by ongoing developments of therapeutic approaches. Concurrent advances in imaging modalities provide eye care professionals with a large amount of data for each patient. Furthermore, with continuous progress in therapeutics, there is an unmet need for reliable structural and functional biomarkers in clinical trials and practice to optimize personalized patient care and evaluate individual responses to treatment. A fast and objective solution is Artificial intelligence (AI), which has revolutionized assessment of AMD in all disease stages. Reliable and validated AI-algorithms can aid to overcome the growing number of patients, visits and necessary treatments as well as maximize the benefits of multimodal imaging in clinical trials. Therefore, there are ongoing efforts to develop and validate automated algorithms to unlock more information from datasets allowing automated assessment of disease activity and disease progression. This review aims to present selected AI algorithms, their development, applications and challenges regarding assessment and prediction of AMD progression.

Disease Activity and Therapeutic Response to Pegcetacoplan for Geographic Atrophy Identified by Deep Learning-Based Analysis of OCT

PURPOSE

To quantify morphological changes of the photoreceptors (PRs) and retinal pigment epithelium (RPE) layers under pegcetacoplan therapy in geographic atrophy (GA) using deep learning-based analysis of OCT images.

DESIGN

Post hoc longitudinal image analysis.

PARTICIPANTS

Patients with GA due to age-related macular degeneration from 2 prospective randomized phase III clinical trials (OAKS and DERBY).

METHODS

Deep learning-based segmentation of RPE loss and PR degeneration, defined as loss of the ellipsoid zone (EZ) layer on OCT, over 24 months.

MAIN OUTCOME MEASURES

Change in the mean area of RPE loss and EZ loss over time in the pooled sham arms and the pegcetacoplan monthly (PM)/pegcetacoplan every other month (PEOM) treatment arms.

RESULTS

A total of 897 eyes of 897 patients were included. There was a therapeutic reduction of RPE loss growth by 22% and 20% in OAKS and 27% and 21% in DERBY for PM and PEOM compared with sham, respectively, at 24 months. The reduction on the EZ level was significantly higher with 53% and 46% in OAKS and 47% and 46% in DERBY for PM and PEOM compared with sham at 24 months. The baseline EZ-RPE difference had an impact on disease activity and therapeutic response. The therapeutic benefit for RPE loss increased with larger EZ-RPE difference quartiles from 21.9%, 23.1%, and 23.9% to 33.6% for PM versus sham (all P < 0.01) and from 13.6% (P = 0.11), 23.8%, and 23.8% to 20.0% for PEOM versus sham (P < 0.01) in quartiles 1, 2, 3, and 4, respectively, at 24 months. The therapeutic reduction of EZ loss increased from 14.8% (P = 0.09), 33.3%, and 46.6% to 77.8% (P < 0.0001) between PM and sham and from 15.9% (P = 0.08), 33.8%, and 52.0% to 64.9% (P < 0.0001) between PEOM and sham for quartiles 1 to 4 at 24 months.

CONCLUSIONS

Deep learning-based OCT analysis objectively identifies and quantifies PR and RPE degeneration in GA. Reductions in further EZ loss on OCT are even higher than the effect on RPE loss in phase 3 trials of pegcetacoplan treatment. The EZ-RPE difference has a strong impact on disease progression and therapeutic response. Identification of patients with higher EZ-RPE loss difference may become an important criterion for the management of GA secondary to AMD.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

The role of complement factor I rare genetic variants in age related macular degeneration in Finland

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the developed world. The alternative pathway (AP) of complement has been linked to the pathogenesis of AMD. In particular, rare variants (RVs) in the complement factor I (CFI) gene encoding the Factor I (FI) protein confer increased AMD risk. The prevalence of CFI RVs are well characterised in European AMD, however little is known about other populations. The Finnish population underwent genetic restriction events which have skewed allele frequencies in unexpected ways. A series of novel or enriched CFI RVs were identified in individuals with dry AMD from the Finnish Biobank Cooperative (FINBB), but the relationship between these genotypes and contribution to disease was unclear. Understanding how RVs impact the ability of FI to regulate the complement system is important to inform mechanistic understanding for how different genotypes contribute to disease development. To explore this a series of in vitro assays were used to functionally characterise the protein products of 3 CFI RVs enriched in FINBB dry AMD, where no prior data were available. The G547R variant resulted in almost complete loss of both classical pathway and AP regulatory potential. The c.982 g>a variant encoding G328R FI perturbed an exon splice enhancer site which resulted in exon skipping and a premature stop codon in vitro and low levels of FI in vivo. Despite detailed analysis no defect in levels or function was demonstrated in T107A. Functional characterization of all Finnish CFI RVs in the cohort allowed us to demonstrate that in Finnish dry AMD, collectively the type 1 CFI RVs (associated with FI haploinsufficiency) were significantly enriched with odds ratio (ORs) of 72.6 (95% confidence interval; CI 16.92 to 382.1). Meanwhile, type 2 CFI RVs (associated with FI dysfunction) collectively conferred a significant OR of 4.97 (95% CI 1.522 to 15.74), and non-impaired or normal CFI RV collectively conferred an of OR 3.19 (95% CI 2.410 to 4.191) although this was driven primarily by G261D. Overall, this study for the first time determined the ORs and functional effect for all CFI RVs within a Geographic Atrophy (GA) cohort, enabling calculations of combined risk scores that underline the risk conferred by type 1 and 2 CFI RVs in GA/AMD.

Modulating the complement system through epitope-specific inhibition by complement C3 inhibitors

As an integral part of the innate immune system, the complement system is a tightly regulated proteolytic cascade, playing a critical role in microbial defense, inflammation activation, and dying host cell clearance. Complement proteins are now emerging as subjects of intense research and drug development, since dysregulation of the complement system plays a critical role in several diseases and disorders, such as paroxysmal nocturnal hemoglobinuria (PNH) and geographic atrophy (GA). Within the complement cascade, complement C3 is the central component, situated at the convergence of all complement activation pathways, rendering it an attractive target for complement-related diseases. However, due to the complicated structure-activity relationship (SAR) of C3, elucidating the mechanisms of C3 inhibition on diverse epitopes is the basis for the rational design of C3-targeted therapeutics. Here, we have developed a set of comprehensive biochemical assays that are tailored to the specific steps within the complement cascade, allowing for a thorough understanding of the pharmacological consequences of different C3 inhibitors at each stage. Utilizing three model inhibitors (MIs) with different epitopes, we found that inhibition of MG4/MG5 domains has potent inhibition efficacy across all the complement activation pathways by interrupting C3-C3 convertase interaction, while inhibition of C345C domain displays a bias over the Alternative pathway (AP) inhibition by impairing AP C3 proconvertase formation. This study elucidates the intricate impact of C3 inhibition by targeting different epitopes, offering valuable insights into understanding the mechanism and facilitating the rational design of C3-targeted therapeutics.

One-Year Outcomes in Subjects Developing Macular Neovascularization While Undergoing Avacincaptad Pegol Therapy for Geographic Atrophy

Purpose

To assess the 12-month outcomes in subjects developing macular neovascularization (MNV) during intravitreal avacincaptad pegol (IVA) treatment for geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

Methods

This research was conducted as a case-controlled, retrospective study of AMD subjects undergoing IVA treatment for GA from two private practice institutions. Subjects were divided into 1) a Study Group of patients who developed MNV and then underwent anti-vascular endothelial growth factor (VEGF) therapy during the study period, and 2) a Control Group of patients who were complication-free during the study period. Both cohorts had a baseline Snellen visual acuity of ≥ 20/200, a baseline GA total area of ≥ 1 mm2and ≤ 17.5 mm2, and 12 months of follow-up after initiation of IVA for GA.

Results

There were 56 patients analyzed. There were no significant differences in baseline features between cohorts. The Study Group had a greater decrease in visual acuity [-0.22 logMAR (-0.27 to -0.17) versus -0.06 logMAR (-0.12 to 0.00); p=<0.0001], and greater GA total lesion growth [1.78 mm2 (1.53-2.03) versus 0.78 mm2 (0.54-1.02); p=<0.0001] during the 12-month study period compared to the Control Group.

Conclusion

Patients developing MNV while undergoing IVA treatment for GA secondary to AMD have worse clinical outcomes despite undergoing anti-VEGF therapy compared to patients who were complication-free at 12-months. This highlights the seriousness of MNV in this patient population and may help specialists counsel patients when considering treatment for GA secondary to AMD.

Evaluating the reliability of a microperimetry-based method for assessing visual function in the junctional zone of geographic atrophy lesions

PURPOSE

To assess the repeatability of a microperimetry methodology for quantifying visual function changes in the junctional zone of eyes with geographic atrophy (GA) in the clinical trial context.

METHODS

A post hoc analysis of the OAKS phase III trial was conducted, which enrolled patients with GA secondary to age-related macular degeneration. Microperimetry using a standard 10 - 2 fovea centered grid was performed at baseline and follow-up visits. GA regions were traced on fundus autofluorescence (FAF) images. Two graders independently registered baseline microperimetry images with baseline FAF images in a sampling of 30 eyes from the OAKS study. Agreement between the two graders' assessments of mean sensitivity and the number of scotomatous points within a ± 250 𝜇m GA junctional zone was assessed.

RESULTS

The intraclass correlation (ICC) and coefficient of repeatability (CoR) for the mean junctional zone sensitivity were 0.987 and 0.214 dB, respectively. The ICC and CoR for the total number of scotomatous points within the junctional zone were 0.991 and 1.42, respectively.

CONCLUSIONS

The repeatability of the methodology and its compatibility with standard MP acquisitions appear to make it well-suited for identifying and analyzing retinal sensitivity within high-risk areas of the retina. We present a microperimetry-based methodology for assessing visual function changes in the junctional zone of geographic atrophy lesions using a standard 10 - 2 fovea centered grid in a clinical trial context. The approach's repeatability and compatibility with standard microperimetry grids may make it useful for assessing the effects of GA therapeutics.

Co-delivery of antioxidants and siRNA-VEGF: promising treatment for age-related macular degeneration

Current treatments for retinal disorders are anti-angiogenic agents, laser photocoagulation, and photodynamic therapies. These conventional treatments focus on reducing abnormal blood vessel formation in the retina, which, in a low-oxygen environment, can lead to harmful proliferation of endothelial cells. This results in dysfunctional, leaky blood vessels that cause retinal edema, hemorrhage, and vision loss. Age-related Macular Degeneration is a primary cause of vision loss and blindness in the elderly, impacting around 20% of those over 50 years old. This complex disease is also closely related to oxidative stress in retina. In this review, we explore the challenge of treating retinal diseases, alternatives and possibilities of enhancing the effectiveness of therapies using co-delivery systems containing both antiangiogenic and antioxidant therapeutic agents. Despite recent proposals potential, the lack of extensive clinical studies on the long-term outcomes and optimal combinations of therapies means that the full risk profile and effectiveness of combined therapy are not yet completely understood. These factors must be carefully considered and managed by healthcare providers to optimize treatment outcomes and ensure patient safety.

Fundus Autofluorescence Variation in Geographic Atrophy of Age-Related Macular Degeneration: A Clinicopathologic Correlation

Purpose

The purpose of this study was to develop ground-truth histology about contributors to variable fundus autofluorescence (FAF) signal and thus inform patient selection for treating geographic atrophy (GA) in age-related macular degeneration (AMD).

Methods

One woman with bilateral multifocal GA, foveal sparing, and thick choroids underwent 535 to 580 nm excitation FAF in 6 clinic visits (11 to 6 years before death). The left eye was preserved 5 hours after death. Eye-tracked ex vivo imaging aligned sub-micrometer epoxy resin sections (n = 140, 60 µm apart) with clinic data. Light microscopic morphology corresponding to FAF features assessed included drusen-driven atrophy, persistent hyperautofluorescence (hyperFAF) islands and peninsulas within atrophy, and hyperFAF and hypoautofluorescence (hypoFAF) inner junctional zone (IJZ) and outer junctional zone (OJZ) relative to descent of external limiting membrane (ELM). Atrophy growth rate was calculated.

Results

HypoFAF atrophic spots appeared in association with drusen, and then expanded and coalesced. Over drusen (n = 45, all calcified), RPE was continuous and thin, photoreceptors were short or absent, and initially intact ELM descended where RPE was absent. In persistent hyperFAF within atrophy and in the OJZ, the RPE was continuous and dysmorphic, photoreceptors were present and short, and BLamD was thick. In the IJZ, mottled FAF corresponded to dissociated RPE atop persistent BLamD. Overall linear growth rate (0.198 mm/ year) typified multifocal GA.

Conclusions

FAF in GA is locally multifactorial, with photoreceptor shortening potentially promoting hyperFAF by increasing incoming excitation light available to RPE fluorophores. RPE dysmorphia may lead to either longer or shorter pathlength for excitation light. At both atrophy initiation and expansion Müller glia are major participants.

Systemic Sodium Iodate Injection as a Model for Expanding Geographic Atrophy

Purpose

Geographic atrophy (GA), an advanced form of dry age-related macular degeneration (AMD), has limited treatment options. This study introduces a novel mouse model featuring an expanding GA patch that can be used to test mechanisms and therapeutics.

Methods

C57Bl/6J male mice (n = 96) aged 9-10 weeks received an intraperitoneal (IP) injection of 20 mg/kg sodium iodate (NaIO3). In vivo confocal scanning laser ophthalmoscope (cSLO) and optical coherence tomography imaging were done at one, four, eight, and 16 weeks after injection, with GA area measurements taken at weeks 8 and 16. Mice were euthanized on weeks 8 and 16 for histological analysis.

Results

Administration of 20 mg/kg intraperitoneal NaIO3 caused variable damage levels. Approximately 22% of cases showed damage (speckled autofluorescence) covering 35% to 90% of the 102° field of view cSLO image at one week after injection. These mice developed an expanding patch of GA by week 8, with a mean 1.45-fold increase in area by week 16. This region showed complete photoreceptor and retinal pigment epithelium loss and complement activation at the atrophy edge, whereas the inner retina remained undamaged. Mice with less damage (48% of cases) only developed incomplete outer retinal degeneration, and mice with more damage (30% of cases) had too much GA for measurable expansion.

Conclusions

Although expanding GA formed in only 22% of mice, the model's simplicity and predictability for GA development via one-week post-injection imaging make it suitable for GA therapeutic experimentation.

Translational Relevance

This murine model provides a valuable tool for testing GA therapies, mirroring clinical endpoints relevant to human trials.

The Landscape of Vascular Endothelial Growth Factor Inhibition in Retinal Diseases

Ever since the US Food and Drug Administration (FDA) approved the first vascular endothelial growth factor (VEGF) antagonist 2 decades ago, inhibitors of VEGF have revolutionized the treatment of a variety of ocular disorders involving pathologic neovascularization and retinal exudation. In this perspective, we evaluate the current status of anti-VEGF therapies and the real-world challenges encountered with maintaining therapeutic outcomes. Finally, we describe novel VEGF-based and combinatorial approaches that are in clinical development.

ReCLAIM-2: A Randomized Phase II Clinical Trial Evaluating Elamipretide in Age-related Macular Degeneration, Geographic Atrophy Growth, Visual Function, and Ellipsoid Zone Preservation

Objective

This study evaluated the safety and efficacy of elamipretide in dry age-related macular degeneration (AMD) with noncentral geographic atrophy (GA).

Design

ReCLAIM-2 was a prospective, phase II, randomized, placebo-controlled, double-masked, multicenter trial (NCT03891875).

Subjects

Patients aged ≥55 years with ≥1 eye with dry AMD with GA were enrolled.

Methods

Administration of daily subcutaneous elamipretide 40 mg was investigated in subjects for 48 weeks followed by a 4-week follow-up period.

Main Outcome Measures

The primary efficacy end points were the mean change from baseline (BL) in low-luminance best-corrected visual acuity (LL BCVA) and the change in square root (Sqrt) converted GA area from BL as measured by OCT. Additional predefined end points included ellipsoid zone (EZ) integrity preservation assessment and categorical changes in LL BCVA. The primary safety end point was the incidence and severity of adverse events.

Results

Of the 176 patients randomized, there were 117 and 59 patients in the elamipretide and placebo groups, respectively. Although elamipretide did not meet statistical significance for the primary end points (mean change in LL BCVA and mean change in Sqrt converted GA area), elamipretide produced a 43% reduction in the mean progression from BL in the macular percentage of total EZ attenuation/loss (i.e., complete loss of EZ band; nominal P = 0.0034) and 47% reduction in the mean progression of macular percentage of partial EZ attenuation/degradation (i.e., EZ-retinal pigment endothelium thickness of ≤20 microns; nominal P = 0.0040) versus placebo at week 48. Elamipretide treatment was also associated with significantly more patients experiencing a ≥10 letter gain in LL BCVA versus placebo (14.6% vs. 2.1%; nominal P = 0.0404). Adverse events were reported in 86% of those receiving elamipretide and 71% of the placebo group with the most common events being injection site reactions (e.g., pruritus, injection site pain, bruising, and erythema).

Conclusions

While the primary end points were not met in this phase II study, elamipretide treatment was associated with a slowing of progressive EZ degradation/loss, a surrogate for photoreceptor damage. These findings have important clinical relevance since EZ attenuation/photoreceptor loss precedes and predicts the progressive pathological changes associated with vision loss and AMD. The EZ attenuation/loss end point will serve as the regulatory approved primary end point in the elamipretide phase III clinical development program.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Differences in imaging biomarkers between patients with intermediate and advanced non-neovascular age-related macular degeneration (AMD) in the University of Colorado AMD registry

PURPOSE

To quantify and compare the different prevalence rates of specific retinal imaging biomarkers in patients with intermediate AMD (iAMD) and advanced non-neovascular AMD (nnAMD).

METHODS

Cross-sectional study of patients with iAMD and advanced nnAMD. Imaging studies were reviewed for qualitative imaging biomarkers. Choroidal thickness measurements were obtained subfoveally and in 1000 um and 2000 um intervals away from the fovea. The Chi-squared test and Fisher's exact test were used to compare rates of imaging biomarkers among the two cohorts. P-value of <0.05 was considered significant.

RESULTS

376 eyes of 197 patients with iAMD and 187 eyes of 97 patients with advanced nnAMD were recruited. There were significantly lower rates of the following imaging biomarkers in the iAMD compared with the advanced nnAMD cohorts: soft drusen (66.0% vs. 84.2%, p = 0.001), calcified drusen (4.3% vs. 40.0%, p < 0.0001), RPD (26.2% vs. 53.3%, p < 0.0001), ORT (0.5% vs. 46.9%, p < 0.0001), RP (1.1% vs. 46.3%, p < 0.0001), pigment migration (53.2% vs. 100%, p < 0.0001), and iRORA (17.9% vs. 80.2%, p < 0.0001). In the iAMD cohort, choroidal thickness was significantly greater at 188 µm (SD: 60) and 194 µm (SD: 69), compared to the advanced nnAMD with measurements of 153 µm (SD: 68), and 161 µm (SD: 76). This difference was statistically significant (p < 0.0001 and p = 0.0002).

CONCLUSIONS

Our results highlight significant differences in imaging biomarkers between both cohorts. Key biomarkers, such as iRORA, RPD, pigment migration, and thinner choroidal thickness, were associated with advanced nnAMD. Identifying these biomarkers early may help target patients who could benefit from new treatments, potentially delaying vision loss.

The Safety of Recently Approved Therapeutics in Age-Related Macular Degeneration

Recent developments in treatments for both forms of advanced age-related macular degeneration (AMD) have led to the approval of multiple agents and modalities within the last few years. Five new medications for both neovascular AMD (nAMD) and geographic atrophy (GA) secondary to nonexudative AMD (neAMD) have been FDA-approved within the last 5 years, along with a new device designed for sustained drug delivery for nAMD. In nAMD, the newest agents approved by the FDA are brolucizumab (Novartis Pharmaceuticals, Basel, Switzerland), faricimab (F. Hoffman-La Roche, Basel, Switzerland), aflibercept 8 mg (Regeneron Pharmaceuticals, Tarrytown, NY, USA), and a new device in the port delivery system with ranibizumab (Genentech, San Francisco, CA, USA). The first agents FDA-approved for GA secondary to neAMD are pegcetacoplan (Apellis Pharmaceuticals, Waltham, MA, USA) and avacincaptad pegol (Iveric Bio, Parsippany, NJ, USA). Evaluation of safety in both clinical trials and the real-world has been of paramount importance after the approval of these newest agents to understand their effects in real patients. Real-world data, as demonstrated in both registrational studies along with retrospective chart review studies, has shown to be an important factor in the implementation of newer drugs, along with the treatment decisions that physicians choose to make regarding their dosing and follow-up. This review article discusses the safety of the most recently approved FDA as seen in both clinical trials and real-world studies.

The Discrepancy Between Visual Acuity Decline and Foveal Involvement in Geographic Atrophy

PURPOSE

To investigate the discrepancy between visual acuity (VA) decline and foveal involvement in geographic atrophy (GA) secondary to nonexudative age-related macular degeneration (AMD), and to explore how early retinal changes impact the progression of visual impairment.

DESIGN

Retrospective, longitudinal cohort study.

SUBJECTS

This study evaluated 80 eyes from 60 patients (mean age, 74.2 ± 10 years) with progressing non-neovascular AMD.

METHODS

Blue-light fundus autofluorescence (FAF) and spectral-domain OCT (SD-OCT) were utilized to monitor GA progression and the onset of foveal involvement. The study analyzed VA changes over an average follow-up of 60 ± 26.4 months, encompassing 785 observations. Mixed-effects models with natural splines assessed the effects of demographic and ocular characteristics on baseline VA and its rate of decline. Survival analyses compared the timing of anatomic changes with the most rapid functional declines, indicated by the highest first derivative of VA trajectories. Discrepancies between visual and anatomic changes were explored using generalized linear mixed-effects models.

MAIN OUTCOME MEASURES

Monthly VA changes, onset and impact of foveal involvement, and factors influencing baseline VA and rate of decline.

RESULTS

Visual acuity declined consistently by an average of 0.010 logarithm of the minimum angle of resolution (LogMAR) per month (standard error [SE], 0.0003; P < 0.001). The onset of foveal involvement significantly exacerbated this decline, adding an average loss of 0.15 LogMAR (SE, 0.02; P < 0.001). Stabilization of VA typically occurred around 41 months post-foveal involvement. Significant factors associated with worse baseline VA were older age, female gender, unifocal GA morphology, and drusen-associated forms of GA (P < 0.05). The most rapid declines in VA typically occurred about 9 months (interquartile range, 0-27 months) before detectable subfoveal changes. The reticular FAF pattern (27/46 [59%] vs. 2/13 [15%], P = 0.02) and smaller baseline GA lesions (P = 0.01) were associated with faster deterioration preceding visible foveal damage.

CONCLUSIONS

This study demonstrates that significant VA loss in GA can precede detectable foveal involvement, suggesting a window for early interventions to slow the progression of visual impairment. Identifying specific GA characteristics and FAF patterns as predictors of rapid VA decline supports the need for personalized treatment strategies to optimize outcomes for patients with nonexudative AMD.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Association of Hyperautofluorescence Signals with Geographic Atrophy Progression in the METformin for the MINimization of Geographic Atrophy Progression Trial

Purpose

To investigate the association between rim area focal hyperautofluorescence (RAFH) signals and geographic atrophy (GA) growth rates, as well as the impact of oral metformin on the longitudinal change of RAFH.

Design

Secondary analysis of a randomized controlled trial.

Participants

Seventy-one eyes from 44 participants with GA and ≥6 months of follow-up in the METformin for the MINimization of geographic atrophy progression study.

Methods

Fundus autofluorescence images were captured using a 488 nm excitation wavelength. Two masked graders identified and measured RAFH lesions using proprietary semiautomatic segmentation software and ImageJ. We calculated RAFH by dividing the areas of hyperautofluorescence within a 450-μm rim circumscribing the GA by the total area enclosed within this rim.

Main Outcome Measures

Longitudinal changes in RAFH and GA area.

Results

Baseline RAFH was positively associated with the baseline square root of GA area 0.065/year (P < 0.001). In the entire study cohort, higher baseline RAFH was associated with a faster GA area growth rate in mm2/year (Spearman's ρ = 0.53; P < 0.001). The association became weaker in square root-transformed GA area growth (ρ = 0.19, P = 0.11) and perimeter-adjusted GA growth rate (ρ = 0.28, P = 0.02), achieving statistical significance only in the latter. When this analysis was stratified into 3 baseline GA tertiles, the first and second tertiles showed weak to moderate association with statistical significance in all 3 modes of GA growth rates. Rim area focal hyperautofluorescence increased slightly but significantly over time at 0.020/year (P < 0.01). Rim area focal hyperautofluorescence increased slightly but significantly over time at 0.020/year (P < 0.01). The use of oral metformin was not significantly associated with the change in RAFH over time compared with the observation group (0.023/year vs. 0.016/year; P = 0.29).

Conclusions

Increased baseline RAFH is associated with faster GA area progression. However, the effect size of this association may depend on the baseline GA lesion size such that small to medium-sized GA lesions display this relationship regardless of the mode of the calculation of GA growth rate.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Oral Antioxidant and Lutein/Zeaxanthin Supplements Slow Geographic Atrophy Progression to the Fovea in Age-Related Macular Degeneration

PURPOSE

To determine whether oral micronutrient supplementation slows geographic atrophy (GA) progression in age-related macular degeneration (AMD).

DESIGN

Post hoc analysis of Age-Related Eye Disease Study (AREDS) and AREDS2, multicenter randomized placebo-controlled trials of oral micronutrient supplementation, each with 2 × 2 factorial design.

PARTICIPANTS

A total of 392 eyes (318 participants) with GA in AREDS and 1210 eyes (891 participants) with GA in AREDS2.

METHODS

The AREDS participants were randomly assigned to oral antioxidants (500 mg vitamin C, 400 IU vitamin E, 15 mg β-carotene), 80 mg zinc, combination, or placebo. The AREDS2 participants were randomly assigned to 10 mg lutein/2 mg zeaxanthin, 350 mg docosahexaenoic acid/650 mg eicosapentaenoic acid, combination, or placebo. Consenting AREDS2 participants were also randomly assigned to alternative AREDS formulations: original; no beta-carotene; 25 mg zinc instead of 80 mg; both.

MAIN OUTCOME MEASURES

(1) Change in GA proximity to central macula over time and (2) change in square root GA area over time, each measured from color fundus photographs at annual visits and analyzed by mixed-model regression according to randomized assignments.

RESULTS

In AREDS eyes with noncentral GA (n = 208), proximity-based progression toward the central macula was significantly slower with randomization to antioxidants versus none, at 50.7 μm/year (95% confidence interval [CI], 38.0-63.4 μm/year) versus 72.9 μm/year (95% CI, 61.3-84.5 μm/year; P = 0.012), respectively. In AREDS2 eyes with noncentral GA, in participants assigned to AREDS antioxidants without β-carotene (n = 325 eyes), proximity-based progression was significantly slower with randomization to lutein/zeaxanthin versus none, at 80.1 μm/year (95% CI, 60.9-99.3 μm/year) versus 114.4 μm/year (95% CI, 96.2-132.7 μm/year; P = 0.011), respectively. In AREDS eyes with any GA (n = 392), area-based progression was not significantly different with randomization to antioxidants versus none (P = 0.63). In AREDS2 eyes with any GA, in participants assigned to AREDS antioxidants without β-carotene (n = 505 eyes), area-based progression was not significantly different with randomization to lutein/zeaxanthin versus none (P = 0.64).

CONCLUSIONS

Oral micronutrient supplementation slowed GA progression toward the central macula, likely by augmenting the natural phenomenon of foveal sparing.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Multiple gene therapy as a tool for regulating the expression of molecules involved in neovascular age-related macular degeneration

Anti-vascular endothelial growth factor (VEGF) therapies have revolutionized the treatment of neovascular age-related macular degeneration (nAMD) and other retinal diseases. However, the necessity for repeated intravitreal injections and the observation of variable treatment responses calls for new treatment modalities where fewer and more effective interventions can result in a clinical effect. Gene therapy might be such an alternative, and therefore the development and clinical application of gene therapy aimed at modifying gene expression has received considerable attention. The article reviews current knowledge of the background, pathophysiological mechanisms, technologies, limitations, and future directions for gene therapy aimed at modifying the synthesis of compounds involved in acquired and senescent retinal disease. The authors have contributed to the field by developing gene therapy to reduce the expression of vascular endothelial growth factor (VEGF), as well as multiple gene therapy for simultaneous downregulation of the synthesis of VEGF and upregulation of pigment epithelium-derived factor (PEDF) using adeno-associated virus (AAV) vectors. It is suggested that such multi-target gene therapy might be included in future treatments of retinal diseases where the underlying mechanisms are complex and cannot be attributed to one specific mediator. Such diseases might include dry AMD (dAMD) with geographic atrophy, but also diabetic macular edema (DME) and retinal vein occlusion (RVO). Gene therapy can be expected to be most beneficial for the patients in need of multiple intra-vitreal injections and in whom the therapeutic response is insufficient. It is concluded, that in parallel with basic research, there is a need for clinical studies aimed at identifying factors that can be used to identify patients who will benefit from gene therapy already at the time of diagnosis of the retinal disease.

Dry and neovascular "wet" age-related macular degeneration: Upcoming therapies

The age-related macular degeneration (AMD) field is witnessing promising advancements in therapeutic options. Breakthrough drugs such as pegcetacoplan and avacincaptad have been FDA-approved for dry AMD, marking a significant development as there were no treatment options until August 2023. While several antivascular endothelial growth factor (VEGF) inhibitors have been approved for wet AMD, challenges persist with the need for frequent dosing. New treatments such as gene therapy, cell therapy, WNT pathway agonists, complement inhibitors, and anti-VEGF combination drugs are under development to address these issues. These developments are exciting and hold promise for transforming the field of medicine, offering hope for improved outcomes and enhanced patient care in managing AMD.

Extent of Complete Retinal Pigment Epithelial and Outer Retinal Atrophy with Foveal Center Involvement is Associated with Visual Acuity

Purpose

To evaluate the OCT images of eyes with fovea-involved complete retinal pigment epithelial and outer retinal atrophy (cRORA) as well as best-corrected visual acuity (BCVA) to explore the pathogenesis of visual impairment and atrophy.

Design

Retrospective observational study.

Subjects

Data of eyes with cRORA associated with age-related macular degeneration with foveal center involvement were collected from 10 hospitals in Japan.

Methods

Ophthalmic examination data, BCVA, and extents of retinal pigment epithelial and outer retinal atrophy (RORA), represented by choroidal hyper-transmission, and outer plexiform layer (OPL) deterioration, central retinal thickness (CRT), and central choroidal thickness (CCT) measured using built-in software on the sectional OCT images were evaluated.

Main Outcome Measures

Relationship between BCVA and extents of RORA and OPL deterioration.

Results

Of the 64 eyes of 64 patients (mean age: 76.8 ± 9.5 years old), 38 eyes (59.4%) belonged to men. Mean BCVA was 0.602 ± 0.475 (median: 0.523; range, -0.079 to 1.523) in logarithm of the minimum angle of resolution (logMAR). Mean extent of RORA was 2921 ± 1291 (median: 3172; range: 479-5985) μm. BCVA in logMAR positively correlated with extents of RORA (P = 0.004) and OPL deterioration (P = 0.004) and negatively correlated with CRT (P = 0.022). Best-corrected visual acuity ≥0.5 was associated with extents of RORA ≥3000 μm (odds ratio [OR], 4.227; 95% confidence interval [CI], 1.440-12.408; P = 0.009) and OPL deterioration ≥1700 μm (OR, 2.984; 95% CI, 1.034-8.609; P = 0.043), and presence of complete central outer plexiform layer defect (cCOD) (OR, 12.700; 95% CI, 2.439-66.132; P = 0.003), after adjusting for age and sex. The extent of RORA ≥3000 μm was associated with BCVA ≥0.5 (OR, 4.213; 95% CI, 1.437-12.356; P = 0.009), extent of OPL deterioration ≥1700 μm (OR, 58.682; 95% CI, 6.865-501.592; P < 0.001), and presence of cCOD (OR, 4.107; 95% CI, 1.339-12.604; P = 0.014), after adjusting for age and sex. The extent of RORA positively correlated with that of OPL deterioration (P < 0.001), CRT (P = 0.001), and CCT (P = 0.041).

Conclusions

A longer extent of cRORA in the OCT images with foveal center involvement was associated with a longer extent of OPL deterioration and the presence of cCOD and worse BCVA. Further studies focusing on OPL changes are warranted for understanding the pathogenesis of RORA and vision loss.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Gallic Acid-Encapsulated PAMAM Dendrimers as an Antioxidant Delivery System for Controlled Release and Reduced Cytotoxicity against ARPE-19 Cells

Poly(amidoamine) (PAMAM) dendrimers have gained significant attention in various research fields, particularly in medicinal compound delivery. Their versatility lies in their ability to conjugate with functional molecules on their surfaces and encapsulate small molecules, making them suitable for diverse applications. Gallic acid is a potent antioxidant compound that has garnered considerable interest in recent years. Our research aims to investigate if the gallic acid-encapsulated PAMAM dendrimer generations 4 (G4(OH)-Ga) and 5 (G5(OH)-Ga) could enhance radical scavenging, which could potentially slow down the progression of age-related macular degeneration (AMD). Encapsulation of gallic acid in PAMAM dendrimers is a feasible alternative to prevent its degradation and toxicity. In vitro investigation of antioxidant activity was carried out using the DPPH and ABTS radical scavenging assays, as well as the FRAP assay. The IC50 values for DPPH and ABTS assays were determined through nonlinear dose-response curves, correlating the inhibition percentage with the concentration (μg/mL) of the sample and the concentration (μM) of gallic acid within each sample. G4(OH)-Ga and G5(OH)-Ga possess significant antioxidant activities as determined by the DPPH, ABTS, and FRAP assays. Moreover, gallic acid-encapsulated PAMAM dendrimers inhibit H2O2-induced reactive oxygen species (ROS) production in the human retinal pigment epithelium ARPE-19 cells, thereby improving antioxidant characteristics and potentially retarding AMD progression caused by ROS. In an evaluation of cell viability of ARPE-19 cells using the MTT assay, G4(OH)-Ga was found to reduce cytotoxic effects on ARPE-19 cells.

Characterizing Patient Perceptions of Living with Geographic Atrophy: The Global Geographic Atrophy Insights Survey

Background

Geographic atrophy (GA) is an advanced form of age-related macular degeneration leading to irreversible vision loss and negative impacts on quality of life.

Methods

To assess the experiences of living with GA, the Geographic Atrophy Insights Survey (GAINS) was conducted between October 12, 2021, and December 10, 2021, captured the responses of individuals ≥60 years with a self-reported GA diagnosis residing in the United States, Canada, Australia, and six European countries. Survey questions focused on the perceptions of individuals living with GA and covered six themes: speed of disease progression, effect on independence, impact on quality of life, emotional toll of GA, misconceptions and need for further education about GA, and clinician interactions. An exploratory comparison between participants with unilateral and bilateral GA was conducted.

Results

The survey included 203 individuals with a mean age of 70 years; 42% had bilateral GA. Most respondents (77%) agreed ("strongly" or "somewhat agreed") that GA impacted their vision faster than expected, and 68% agreed that it is hard to enjoy life fully the way they did before GA diagnosis. Regarding comparisons between individuals with bilateral and unilateral GA, both groups reported similar "major" or "moderate" negative impacts on their ability to drive (73% vs 75%, respectively), followed by the ability to read (66% vs 71%), and ability to travel as much as they would prefer (62% vs 62%). Among participants, 49% and 56% of respondents with bilateral and unilateral GA, respectively, reported major/moderate negative impacts on self-confidence and 40% of both cohorts reported major/moderate negative impacts on mental health.

Conclusion

Our survey provides further insight on the burden experienced by individuals living with GA. We find similar responses between unilateral and bilateral GA groups, highlighting the impact GA may have on an individual's quality of life even when only one eye is affected.

Characterization of drusen formation in a primary porcine tissue culture model of dry AMD

Age-related macular degeneration (AMD) affects millions of individuals worldwide and is a leading cause of blindness in the elderly. In dry AMD, lipoproteinaceous deposits called drusen accumulate between the retinal pigment epithelium (RPE) and Bruch's membrane, leading to impairment of oxygen and nutrient trafficking to the neural retina, and degeneration of the overlying photoreceptor cells. Owing to key differences in human and animal ocular anatomy and the slowly progressing nature of the disease, AMD is not easily modeled in vivo. In this study, we further characterize a "drusen-in-a-dish" primary porcine RPE model system by employing vital lipid staining to monitor sub-RPE deposition over time in monolayers of cells cultured on porous transwell membranes. We demonstrate for the first time using a semi-automated image analysis pipeline that the number and size of sub-RPE deposits increases gradually but significantly over time and confirm that sub-RPE deposits grown in culture immunostain positive for multiple known components found in human drusen. As a result, we propose that drusen-in-a-dish cell culture models represent a high-throughput and cost-scalable alternative to animal models in which to study the pathobiology of drusen accumulation and may serve as useful tools for screening novel therapeutics aimed at treating dry AMD.

Local OCT Structural Correlates of Deep Visual Sensitivity Defects in Early Atrophic Age-Related Macular Degeneration

PURPOSE

To determine local OCT structural correlates of deep visual sensitivity defects (threshold of ≤10 decibels on microperimetry) in early atrophic age-related macular degeneration (AMD).

DESIGN

Prospective observational study.

PARTICIPANTS

Forty eyes from 40 participants, with at least incomplete retinal pigment epithelium (RPE) and outer retinal atrophy, or more advanced atrophic lesion(s).

METHODS

Participants underwent ≥2 targeted, high-density microperimetry tests of atrophic lesions of interest in 1 eye, and high-density 3×3-mm volume scans of that region on a swept-source OCT angiography device, all at a single visit. Seven OCT-defined features of atrophy were manually annotated: hypertransmission, RPE attenuation/disruption, complete RPE loss, ellipsoid zone disruption, external limiting membrane (ELM) disruption, subsidence of the outer plexiform layer and inner nuclear layer, and/or hyporeflective wedge-shaped band, and outer nuclear layer (ONL) thickness.

MAIN OUTCOME MEASURES

Association between OCT-defined features of atrophy and presence of a deep visual sensitivity defect at a local, pointwise level.

RESULTS

All OCT-defined features of atrophy were individually associated with the presence of a deep visual sensitivity defect at a pointwise level in univariable mixed-effects logistic regression analyses (P < 0.001 for all). However, only hypertransmission, complete RPE loss, ELM disruption, and ONL thickness remained significantly and independently associated with deep visual sensitivity defects in a multivariable analysis (P ≤ 0.011). A prediction model incorporating these 4 OCT features (partial area under the curve [pAUC] at ≥90% specificity = 0.80) outperformed models using any single feature alone in predicting the presence of deep visual sensitivity defects (pAUC = 0.65 to 0.78, respectively; P ≥ 0.040).

CONCLUSIONS

The study identified hypertransmission, complete RPE loss, ELM disruption, and ONL thickness as key OCT-defined features of atrophy independently associated with deep visual sensitivity defects. These findings are important when considering anatomical outcome measures for evaluating interventions for early atrophic AMD that are most likely to capture beneficial treatment effects that will be accompanied by evidence of functional preservation if measured directly.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Different Therapeutic Approaches for Dry and Wet AMD

Age-related macular degeneration (AMD) is the most common cause of irreversible loss of central vision in elderly subjects, affecting men and women equally. It is a degenerative pathology that causes progressive damage to the macula, the central and most vital part of the retina. There are two forms of AMD depending on how the macula is damaged, dry AMD and wet or neovascular AMD. Dry AMD is the most common form; waste materials accumulate under the retina as old cells die, not being replaced. Wet AMD is less common, but can lead to vision loss much more quickly. Wet AMD is characterized by new abnormal blood vessels developing under the macula, where they do not normally grow. This frequently occurs in patients who already have dry AMD, as new blood vessels are developed to try to solve the problem. It is not known what causes AMD to develop; however, certain risk factors (i.e., age, smoking, genetic factors) can increase the risk of developing AMD. There are currently no treatments for dry AMD. There is evidence that not smoking, exercising regularly, eating nutritious food, and taking certain supplements can reduce the risk of acquiring AMD or slow its development. The main treatment for wet AMD is inhibitors of VEGF (vascular endothelial growth factor), a protein that stimulates the growth of new blood vessels. VEGF inhibitors can stop the growth of new blood vessels, preventing further damage to the macula and vision loss. In most patients, VEGF inhibitors can improve vision if macular degeneration is diagnosed early and treated accordingly. However, VEGF inhibitors cannot repair damage that has already occurred. Current AMD research is trying to find treatments for dry AMD and other options for wet AMD. This review provides a summary of the current evidence regarding the different treatments aimed at both forms of AMD with particular and greater attention to the dry form.

Longitudinal Changes of Visual Sensitivity With Geographic Atrophy Progression Assessed by Defect-Mapping Microperimetry

Purpose

To determine the relationship between structural and functional changes over time in the progression of geographic atrophy (GA) as assessed by defect-mapping microperimetry, an approach optimized to characterize the spatial extent of deep visual sensitivity losses.

Methods

A total of 57 eyes from 50 participants underwent defect-mapping microperimetry testing of the central 8° radius (with a 10-dB stimuli presented once each at 208 locations) over a median of five visits, scheduled at 3-monthly intervals. GA lesion(s) on fundus autofluorescence in the corresponding region tested on microperimetry at each visit were manually annotated.

Results

At a global level, change of GA extent in the central 8° radius explained a large proportion of the variance in the change in the proportion of locations missed (nonresponse) on defect-mapping microperimetry (R2 = 0.52). Locally, test locations that were entirely outside or within GA lesion(s) had a 0.3% (P = 0.305) and 2.3% (P < 0.001) probability of worsening between the two visits, respectively. In contrast, test locations with a 0% to 25%, 25% to 50%, 50% to 75%, or 75% to 100% change in the extent of GA overlapping between visits had a 4.1%, 12.0%, 17.5%, and 37.9% probability of worsening, respectively (all P < 0.001).

Conclusions

This study confirms that longitudinal changes in GA extent are associated with functional changes on defect-mapping microperimetry, both on a global and local level. These findings highlight the expected functional relevance of GA progression, and demonstrates the potential effectiveness of this microperimetry testing strategy for capturing visual function decline associated with GA progression.

Short-term efficacy of photobiomodulation in early and intermediate age-related macular degeneration: the PBM4AMD study

OBJECTIVES

This independent prospective study evaluated the short-term effects and safety of photobiomodulation (PBM) in early and intermediate age-related macular degeneration.

METHODS

patients were treated with PBM in one eye. Functional parameters and drusen volume were measured at one (W4), three- (W12) and six-months (W24) after PBM.

RESULTS

The study included 38 subjects who completed the PBM protocol. Two patients developed macular neovascularization during the study period. Best corrected visual acuity improved from 77.82 ± 5.83 ETDRS letters at baseline to 82.44 ± 5.67 at W12 (p < 0.01), then declined to 80.05 ± 5.79 at W24 (p < 0.01 vs. baseline). Low luminance visual acuity showed a similar pattern, improving from 61.18 ± 8.58 ETDRS letters at baseline to 66.33 ± 8.55 at W12 (p < 0.01), and decreasing to 62.05 ± 9.71 at W24 (p = 0.02). Contrast sensitivity improved at W12 (20.11 ± 9.23 ETDRS letters, p < 0.01), but returned to baseline by W24 (16.45 ± 9.12, p = 0.5). Scotopic microperimetry showed a decrease in mean absolute retinal sensitivity from 9.24 ± 3.44 dB to 7.47 ± 4.41 dB at W24 (p < 0.01), while relative sensitivity decreased only at W24 (p = 0.04). Drusen volume decreased at W4 (0.018 ± 0.009 mm3, p < 0.01) and W12 (0.017 ± 0.009 mm3, p < 0.01), with a slight increase at W24 (0.019 ± 0.012 mm3, p = 0.154).

CONCLUSIONS

PBM resulted in temporary improvements in visual function and a reduction in drusen volume, but these effects were not sustained at six months. The long-term efficacy and impact on disease progression are uncertain, necessitating further research to confirm these findings and determine optimal patient selection.