The Issue of End Point Discordance in Dry Age-Related Macular Degeneration: How Might Clinical Trials Demonstrate a Functional Benefit?

Visual Loss in Geographic Atrophy: Learnings from the Lampalizumab Trials

PURPOSE

To assess the correlation of lesion growth rate and baseline factors, including foveal involvement and focality, on visual loss as measured by best-corrected visual acuity (BCVA) in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

DESIGN

Retrospective analysis of the lampalizumab phase 3 (NCT02247479 and NCT02247531) and prospective observational (NCT02479386) trials.

PARTICIPANTS

Patients with bilateral GA.

METHODS

Monthly BCVA and fundus autofluorescence (FAF) at baseline and every 6 months for 2 years were analyzed. Baseline GA area from FAF images was correlated to baseline BCVA and change in BCVA. The lesion growth rate was calculated as the slope of a linear fit from all available GA area measurements of a patient. The association between GA growth rate quartiles and BCVA changes was assessed, subgrouped by GA foveal involvement or focality. Time-to-event analysis for BCVA loss of ≥5, ≥10, and ≥15 letters was performed. A Cox regression model adjusted for baseline factors was performed on these outcomes. Kaplan-Meier curves are provided for each baseline factor and GA growth rate.

MAIN OUTCOME MEASURES

Correlations of baseline BCVA, GA area, and growth rate with change in BCVA, and time to ≥5, ≥10, and ≥15-letter loss by foveal involvement or focality.

RESULTS

Best-corrected visual acuity and GA area at baseline did not correlate with BCVA change at any visit. Geographic atrophy growth rate showed a weak correlation with BCVA loss, which increased over time. The 2 highest GA growth rate quartiles had accelerated BCVA loss in eyes with subfoveal, unifocal lesions. Approximately 75%, 50%, and 25% of study eyes experienced a ≥5-, ≥10-, and ≥15-letter loss by 2 years, respectively.

CONCLUSIONS

Best-corrected visual acuity and GA area at baseline did not correlate with BCVA loss, but faster GA growth rates appeared to be associated with faster BCVA loss. Geographic atrophy foveal involvement and focality correlated with the rate of BCVA loss with subfoveal lesions at high risk of vision loss over time, especially when the GA lesion was unifocal.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Relationships Between Diet and Geographic Atrophy Progression in the Age-Related Eye Diseases Studies 1 and 2

Background/Objectives: The objective of this study was to analyze the relationships between diet and geographic atrophy (GA) progression, both area-based and proximity-based, for dietary pattern, components, and micronutrients. Methods: In the Age-Related Eye Diseases Study (AREDS) and AREDS2, an Alternative Mediterranean Diet Index (aMedi), its nine components, and individual micronutrient intakes were calculated. Mixed-model regression was performed for square root GA area, GA foveal proximity, and acuity. Results: The study populations comprised 657 (AREDS) and 1179 eyes (AREDS2). For area-based progression, a higher aMedi was associated with slower progression in AREDS2 and (in analyses excluding MUFA:SFA) AREDS. A higher intake was associated with slower progression for seven components (including vegetables and fruit at Bonferroni) and four components (including fruit and less red meat at Bonferroni), and seven and 15 nutrients, in AREDS1/2, respectively. For proximity-based progression, a higher aMedi was associated with slower progression in AREDS. A higher intake was associated with slower progression for three components (including vegetables at Bonferroni) and two components, and 10 and 8 nutrients, in AREDS1/2, respectively. With increasing oral supplementation, associations between proximity-based progression and aMedi/components/nutrients were weaker. In AREDS2 eyes with non-central GA, higher aMedi was associated with a slower acuity decline. Conclusions: A Mediterranean-type diet is associated with slower GA area-based progression and slower progression to the fovea, accompanied by a slower decline in acuity. The most important components and micronutrients for incidence, area-based progression, and foveal progression overlap only partially. For the latter two, they include vegetables, fruit, and less red meat. These findings suggest the benefits of targeted nutritional and supplementation strategies.

Photoreceptor assessment in age-related macular degeneration

Clinical trials investigating drugs for various stages of age-related macular degeneration (AMD) are actively underway and there is a strong interest in outcomes that demonstrate a structure-function-correlation. The ellipsoid zone (EZ), a crucial anatomical feature affected in this disease, has emerged as a strong contender. There is significant interest in evaluating EZ metrics on Optical Coherence Tomography (OCT), such as integrity and reflectivity, as disruption of this photoreceptor-rich layer may indicate disease progression. Loss of photoreceptor integrity in the junctional zone of geographic atrophy (GA) has been shown to exceed the areas of retinal pigment epithelial (RPE) atrophy, thus predicting future GA expansion. Furthermore, reduced visual acuity and retinal sensitivity have been correlated with loss of EZ integrity, underscoring a structure-function relationship. Photoreceptor integrity has also recently been acknowledged by the Food and Drug Administration (FDA), supporting its use as a primary endpoint in clinical trials investigating treatments for GA. However, the segmentation of this EZ still poses challenges. Continuous enhancements in OCT resolution and advancements in automated segmentation algorithms contribute to improved assessment of the EZ, strengthening its potential as an imaging biomarker for assessing photoreceptor function. It remains to be seen whether the EZ will serve as a surrogate marker for intermediate AMD. This article aims to provide an overview of the current understanding and knowledge of the EZ, while addressing ongoing challenges encountered in its assessment and interpretation.

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.

Drug Approval for the Treatment of Geographic Atrophy: How We Got Here and Where We Need to Go

PURPOSE

To discuss the clinical trial results leading to the US Food and Drug Administration (FDA) approval of anti-complement therapies for geographic atrophy (GA), perspectives on functional data from the GA clinical trials, and how lessons from the FDA approval may guide future directions for basic and clinical research in AMD.

DESIGN

Selected literature review with analysis and perspective METHODS: We performed a targeted review of publicly available data from the clinical trials of pegcetacoplan and avacincaptad for the treatment of GA, as well as scientific literature on the natural history of GA and the genetics and basic science of complement in AMD.

RESULTS

The approval of pegcetacoplan and avacincaptad was based on an anatomic endpoint of a reduction in the rate of GA expansion over time. However, functional data from 2 phase 3 clinical trials for each drug demonstrated no visual benefit to patients in the treatment groups. Review of the genetics of AMD and the basic science of the role for complement in AMD provides only modest support for targeting complement as treatment for GA expansion, and alternative molecular targets for GA treatment are therefore discussed. Reasons for the disconnect between anatomic and functional outcomes in the clinical trials of anti-complement therapies are discussed, providing insight to guide the configuration of future clinical studies for GA.

CONCLUSION

Although avacincaptad and pegcetacoplan are our first FDA-approved treatments for GA, results from the clinical trials failed to show any functional improvement after 1 and 2 years, respectively, calling into question whether the drugs represent a "clinically relevant outcome." To improve the chances of more impactful therapies in the future, we provide basic-science rationale for pursuing non-complement targets; emphasize the importance of ongoing clinical research that more closely pins anatomic features of GA to functional outcomes; and provide suggestions for clinical endpoints for future clinical trials on GA.

Piloting a forced-choice task to elicit treatment preferences in geographic atrophy

OBJECTIVE

Geographic Atrophy (GA) is the advanced form of the non-neovascular ('dry') type of age-related macular degeneration (AMD) and responsible for one-quarter of legal blindness in the UK. New therapies delivered by intravitreal injection are in late-stage development, and two such therapies (pegcetacoplan (Syfovre) and avacincaptad pegol (Izervay)) have now been approved for clinical use by the US Food and Drug Administration. These therapies slow down, but do not stop or reverse, progression of GA and they may also increase the risk of developing the neovascular ('wet') type of AMD. Within a larger study exploring the acceptability of these new treatments to people living with GA, we developed a forced-choice exercise to evaluate how participants weigh up benefits and drawbacks of different treatment regimens. This research note reports quantitative and qualitative findings from this exercise.

RESULTS

Twenty-eight participants took part in this exercise. The exercise demonstrated that participants were generally, although not unanimously, in favour of less frequent treatment for GA that was slightly less efficacious in terms of preserving visual function but presented a lower risk of developing wet AMD. Even among a small sample, the exercise demonstrated the highly personal and idiosyncratic decision-making processes influencing participants' choices of preferred hypothetical GA treatment.