Treatment of dry age-related macular degeneration: A review.

Age-related macular degeneration is a global disease with a significant societal impact. The advent of anti-vascular endothelial growth factor therapy (anti-VEGF) has revolutionised the treatment of neovascular age-related macular degeneration (nAMD). Dry age-related macular degeneration (dAMD) is being investigated for possible therapeutic options. The therapeutic categories undergoing clinical trials include complement pathway inhibitors, visual cycle modulators, reduction of toxic byproducts, antioxidative therapy, neuroprotective agents, laser therapy, surgical options, gene therapy, stem cell therapy, and miscellaneous treatments. Two intravitreal anti-complement factors (pegcetacoplan and avacincaptad pegol) have recently shown phase 3 clinical trial evidence of a reduction in the growth of geographic atrophy. In this review, we provide an update on treatment options currently undergoing clinical research trials for the management of dAMD and preventing the progression of Geographic Atrophy (GA).

RPE-Directed Gene Therapy Improves Mitochondrial Function in Murine Dry AMD Models.

Age-related macular degeneration (AMD) is the most common cause of blindness in the aged population. However, to date there is no effective treatment for the dry form of the disease, representing 85-90% of cases. AMD is an immensely complex disease which affects, amongst others, both retinal pigment epithelium (RPE) and photoreceptor cells and leads to the progressive loss of central vision. Mitochondrial dysfunction in both RPE and photoreceptor cells is emerging as a key player in the disease. There are indications that during disease progression, the RPE is first impaired and RPE dysfunction in turn leads to subsequent photoreceptor cell degeneration; however, the exact sequence of events has not as yet been fully determined. We recently showed that AAV delivery of an optimised NADH-ubiquinone oxidoreductase (NDI1) gene, a nuclear-encoded complex 1 equivalent from S. cerevisiae, expressed from a general promoter, provided robust benefit in a variety of murine and cellular models of dry AMD; this was the first study employing a gene therapy to directly boost mitochondrial function, providing functional benefit in vivo. However, use of a restricted RPE-specific promoter to drive expression of the gene therapy enables exploration of the optimal target retinal cell type for dry AMD therapies. Furthermore, such restricted transgene expression could reduce potential off-target effects, possibly improving the safety profile of the therapy. Therefore, in the current study, we interrogate whether expression of the gene therapy from the RPE-specific promoter, Vitelliform macular dystrophy 2 (VMD2), might be sufficient to rescue dry AMD models.

Emerging treatments for geographic atrophy in age-related macular degeneration.

PURPOSE OF REVIEW: This review describes therapeutic research programs for geographic atrophy (GA) due to age-related macular degeneration (AMD). We highlight clinical trial data from phase I, II, and III studies. RECENT FINDINGS: There are currently no treatments for GA, a form of advanced AMD that causes significant visual morbidity. Currently, therapeutic candidates are being developed to delay further progression of GA or even attempt to reverse some of the damage. The approaches to therapy range from molecular targets to cell transplantation. Studies of these novel treatment approaches have demonstrated varying degrees of success. The progress in understanding the disease pathophysiology as well as clinical trial data is reviewed. SUMMARY: There are promising new treatments to prevent GA progression as well as some that may reverse the disease course.

Geographic atrophy: where we are now and where we are going.

PURPOSE OF REVIEW: Age-related macular degeneration (AMD) affects a significant percentage of the elderly population and end-stage disease classified by either geographic atrophy (GA) or neovascular AMD (nvAMD) is one of the leading causes of vision loss worldwide. Despite the fact that there are currently treatments for nvAMD, there are no treatments in practice to prevent disease onset or progression of GA. This topic is at the forefront of ophthalmic research demonstrated by the recent advances in disease characterization, genetic and environmental risk factor classification, biomarker discovery and mechanism of pathogenesis categorization. There are also numerous clinical treatment trials underway, targeting proposed pathways and biomarkers associated with GA that are promising. RECENT FINDINGS: With several clinical trials of potential treatments underway and numerous recent publications on disease diagnosis and classification, the understanding of GA pathogenesis has increased substantially. Although the exact mechanism of pathology is still elusive, recent literature has highlighted the utilization of current and new ophthalmic imaging modalities and discovery of objective and functional markers that can lead to earlier diagnosis and treatment. SUMMARY: Herein, we will provide an overview and discussion of the current status of GA including advances in mechanism of pathogenesis, diagnosis, classification and current treatment modalities.

The role of complement membrane attack complex in dry and wet AMD - From hypothesis to clinical trials.

Data from human dry and wet age-related macular degeneration (AMD) eyes support the hypothesis that constant 'tickover' of the alternative complement pathway results in chronic deposition of the complement membrane attack complex (MAC) on the choriocapillaris and the retinal pigment epithelium (RPE). Sub-lytic levels of MAC lead to cell signaling associated with tissue remodeling and the production of cytokines and inflammatory molecules. Lytic levels of MAC lead to cell death. CD59 is a naturally occurring inhibitor of the assembly of MAC. CD59 may thus be therapeutically efficacious against the pathophysiology of dry and wet AMD. The first gene therapy clinical trial for geographic atrophy - the advanced form of dry AMD has recently completed recruitment. This trial is studying the safety and tolerability of expressing CD59 from an adeno-associated virus (AAV) vector injected once into the vitreous. A second clinical trial assessing the efficacy of CD59 in wet AMD patients is also under way. Herein, the evidence for the role of MAC in the pathophysiology of dry as well as wet AMD and the scientific rationale underlying the use of AAV- delivered CD59 for the treatment of dry and wet AMD is discussed.

[Dry AMD - Cellular and Genetic Therapies]. / Trockene AMD ­ zelluläre und gentherapeutische Behandlungsansätze.

The growing incidence of neurodegenerative diseases is based on our increasingly aging society as well as the difficulties in establishing defined therapy regimens. For dry age-related macular degeneration (AMD) and the later stage of geographic atrophy (GA), various treatment options exist that only decelerate the progression of the disease. However, no therapy is currently available that can restore the degenerated retinal pigment epithelium (RPE) and/or photoreceptor cells. Cellular and gene-based approaches aim for the regeneration of the degenerated cells and/or the continuous secretion of cell-protecting agents. The article describes the approaches that are currently being investigated in different clinical trials. These trials are based on the use of cell-based drug delivery systems, stem cells of different origins as well as virus-mediated gene therapy approaches. Finally, we give an overview of ongoing therapeutic developments and present our own research activities, which consist of a combination of pigment epithelial cell transplantation and additive non-viral gene therapy to treat retinal degenerative diseases.

Recent approaches to evaluating and monitoring geographic atrophy.

PURPOSE OF REVIEW: Given the increasing prevalence of geographic atrophy from age-related macular degeneration as the number of individuals over 85 increases throughout the world, as well as the recent increase in potential treatments to slow growth of geographic atrophy, this article discusses recent findings regarding retinal imaging of geographic atrophy to detect its presence or expansion over time. RECENT FINDINGS: During the review period, the COMPLETE (Systemic complement inhibition with eculizumab for geographic atrophy in age-related macular degeneration) and the GATE (Randomized trial to evaluate tandospirone in geographic atrophy secondary to age-related macular degeneration) studies, respectively, reported no beneficial effects of intravenous eculizumab or tandospirone eye drops, respectively, identified on the growth of geographic atrophy. Several imaging and visual function studies have evaluated the role of various techniques using fundus autofluorescence, optical coherence tomography, microperimetry, or other investigator-initiated tools to assess geographic atrophy growth or progression over time, although the ideal imaging for geographic atrophy remains unknown. Some predictive factors for geographic atrophy growth recently suggested include genetic features, geographic atrophy characteristics in the fellow eye, or the presence of outer retinal tubulation on optical coherence tomography. SUMMARY: Quantification of geographic atrophy is important for evaluating growth of geographic atrophy. Numerous new imaging techniques of geographic atrophy beyond human grading of fundus photographs or fluorescein angiograms have emerged, but the ideal imaging for geographic atrophy has yet to be determined.

Geographic Atrophy and Choroidal Neovascularization in the Same Eye: A Review.

Geographic atrophy (GA) and choroidal neovascularization (CNV), the two late forms of age-related macular degeneration, are generally considered two distinct entities. However, GA and CNV can occur simultaneously in the same eye, with GA usually occurring first. The prevalence of this combined entity is higher in histological studies than in clinical studies. No distinct systemic or genetic risk characteristics are associated with the combined GA/CNV entity, although on clinical examination and retinal imaging it can feature drusen or subretinal drusenoid deposits. GA and CNV may exist within the spectrum of a single disease, or they may be two very different diseases. Therapy with antivascular endothelial growth factor (anti-VEGF) is often successful for CNV, but some evidence suggests increased rates of GA development in eyes treated with anti-VEGF. In this article, we review the current literature regarding the epidemiology, clinical presentation, and treatment options for patients with the combined GA/CNV entity.

Challenges in the Development of Therapy for Dry Age-Related Macular Degeneration.

Dry age-related macular degeneration (AMD), a multifactorial progressive degenerative disease of the retinal photoreceptors, pigmented epithelium and Bruch's membrane/choroid in central retina, causes visual impairment in millions of elderly people worldwide. The only available therapy for this disease is the over-the-counter (OTC) multi-vitamins plus macular xanthophyll (lutein/zeaxanthin) which attempts to block the damages of oxidative stress and ionizing blue light. Therefore development of dry AMD prescribed treatment is a pressing unmet medical need. However, this effort is currently hindered by many challenges, including an incomplete understanding of the mechanism of pathogenesis that leads to uncertain targets, confounded by not yet validated preclinical models and the difficulty to deliver the drugs to the posterior segment of the eye. Additionally, with slow disease progression and a less than ideal endpoint measurement method, clinical trials are necessarily large, lengthy and expensive. Increased commitment to research and development is an essential foundation for dealing with these problems. Innovations in clinical trials with novel endpoints, nontraditional study designs and the use of surrogate diseases might shorten the study time, reduce the patient sample size and consequently lower the budget for the development of the new therapies for the dry AMD.

Geographic atrophy: clinical features and potential therapeutic approaches.

In contrast to wet age-related macular degeneration (AMD), where loss of vision is typically acute and treatment leads to a relatively rapid reduction in retinal fluid and subsequent improvements in visual acuity (VA), disease progression and vision loss in geographic atrophy (GA) owing to AMD are gradual processes. Although GA can result in significant visual function deficits in reading, night vision, and dark adaptation, and produce dense, irreversible scotomas in the visual field, the initial decline in VA may be relatively minor if the fovea is spared. Because best-corrected VA does not correlate well with GA lesions or progression, alternative clinical endpoints are being sought. These include reduction in drusen burden, slowing the enlargement rate of GA lesion area, and slowing or eliminating the progression of intermediate to advanced AMD. Among these considerations, slowing the expansion of the GA lesion area seems to be a clinically suitable primary efficacy endpoint. Because GA lesion growth is characterized by loss of photoreceptors, it is considered a surrogate endpoint for vision loss. Detection of GA can be achieved with a number of different imaging techniques, including color fundus photography, fluorescein angiography, fundus autofluorescence (FAF), near-infrared reflectance, and spectral-domain optical coherence tomography. Previous studies have identified predictive characteristics for progression rates including abnormal patterns of FAF in the perilesional retina. Although there is currently no approved or effective treatment to prevent the onset and progression of GA, potential therapies are being evaluated in clinical studies.

A phase ia dose-escalation study of the anti-factor D monoclonal antibody fragment FCFD4514S in patients with geographic atrophy.

PURPOSE: Multicenter, open-label, single-dose, dose-escalation Phase Ia study to determine the safety, tolerability, maximum tolerated dose, and immunogenicity of FCFD4514S, an antigen-binding fragment from a humanized monoclonal antibody directed against complement factor D, in patients with geographic atrophy. METHODS: Eighteen patients with geographic atrophy (lesion size: ≥ 0.75 disk areas; best-corrected visual acuity: 20/125-20/400 Snellen equivalent) were sequentially enrolled and received 1 of 6 escalating doses of intravitreal FCFD4514S subject to dose-limiting toxicity criteria. Follow-up assessments (clinical examination, best-corrected visual acuity, intraocular pressure) were conducted at postadministration Days 1, 3, 7, 14, 30, 60, and 90. Serum pharmacokinetics, immunogenicity, and complement activity were also evaluated. RESULTS: All patients completed the study with no reported FCFD4514S-related dose-limiting toxicities or ocular or systemic adverse events. The maximum tolerated dose for this study was 10 mg, the highest dose tested. No antitherapeutic antibody response or adverse effects on systemic complement activity were observed. Time to maximum serum concentration was 1 day to 3 days postdosing; serum terminal half-life was 5.9 days. CONCLUSION: Single-dose intravitreal FCFD4514S administrations were safe and well tolerated and not associated with any study drug-related ocular or systemic adverse events. These data support a multidose safety and tolerability assessment of FCFD4514S in geographic atrophy.

Age-related macular degeneration: linking clinical presentation to pathology.

Age-related macular degeneration (AMD) is one of the leading causes of blindness worldwide in the elderly population. Optometrists, as primary eye health care providers, require the skills and knowledge to accurately diagnose and manage AMD patients. There is an overwhelming body of research related to the clinical presentation, etiology, epidemiology, and pathology of this disease. Additionally, the evolution of new imaging modalities creates new opportunities to clinically detect and analyze previously uncharacterized and earlier changes in the retina. The challenge for optometrists is to combine all this information into an applicable knowledge base for use in everyday clinical assessment of AMD so that timely and accurate referrals can be made to retinal specialists. This review attempts to address this issue by linking the clinical presentation of AMD with the underlying disease biology. We emphasize the contribution of recent noninvasive imaging technologies to the clinical assessment of early and more advanced AMD including optical coherence tomography, fundus autofluorescence, and infrared reflectance.

A Cost-Effectiveness Analysis of Pegcetacoplan for the Treatment of Geographic Atrophy.

PURPOSE: To evaluate the cost-effectiveness of the treatment of geography atrophy (GA) with intravitreal pegcetacoplan and to identify utility-measurement surrogates. DESIGN: Cost analysis based on data from a published study. SUBJECTS: None; based on data from published sham control compared with 2 treatment groups in the index study. METHODS: Costs were based on 2022 Medicare reimbursement data. Specific outcomes were extrapolated from the DERBY and OAKS trials. Assumptions were made for the lifetime analysis based on a theoretical logistic growth model of the atrophy. OUTCOME MEASURES: Cost, cost utility, cost per quality-adjusted life-year, and cost per area of GA (in US$). RESULTS: The costs to treat GA in every month (EM) and every-other-month (EOM) treatment groups over the 2 years as reported were $70 000 and $34 600, respectively. The costs per area of delaying GA for 2 years in all patients were $87 300/mm2 (EM) and $49 200/mm2 (EOM), and in initially extrafoveal patients, $53 900/mm2 (EM) and $32 100/mm2 (EOM). The costs per day of delaying GA for 2 years were $295 (EM) and $170 (EOM); the marginal cost (EM vs. EOM) per retinal pigment epithelium cell saved was $30. The modeled lifetime costs were $350 000 (EM) and $172 000 (EOM), or $309 000/mm2 (EM) and $180 000 (EOM) /mm2. The modeled time to 95% atrophy at 13 years was delayed by 2.5 years (EM) and 2.1 years (EOM). The costs/quality-adjusted life-year gained based on modeled visual loss with 95% atrophy were $706 000 (EM) and $397 000 (EOM). CONCLUSION: Treatment of GA with intravitreal pegcetacoplan EOM was more cost effective than EM. Treatment of extrafoveal lesions yielded greater utility than the treatment of the entire group. As atrophy progression approaches an upper limit, the marginal cost/benefit ratios increase. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The Role of Inflammation in Age-Related Macular Degeneration-Therapeutic Landscapes in Geographic Atrophy.

Age-related macular degeneration (AMD) is the leading cause of vision loss and visual impairment in people over 50 years of age. In the current therapeutic landscape, intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapies have been central to the management of neovascular AMD (also known as wet AMD), whereas treatments for geographic atrophy have lagged behind. Several therapeutic approaches are being developed for geographic atrophy with the goal of either slowing down disease progression or reversing sight loss. Such strategies target the inflammatory pathways, complement cascade, visual cycle or neuroprotective mechanisms to slow down the degeneration. In addition, retinal implants have been tried for vision restoration and stem cell therapies for potentially a dual purpose of slowing down the degeneration and restoring visual function. In particular, therapies focusing on the complement pathway have shown promising results with the FDA approved pegcetacoplan, a complement C3 inhibitor, and avacincaptad pegol, a complement C5 inhibitor. In this review, we discuss the mechanisms of inflammation in AMD and outline the therapeutic landscapes of atrophy AMD. Improved understanding of the various pathway components and their interplay in this complex neuroinflammatory degeneration will guide the development of current and future therapeutic options, such as optogenetic therapy.

Diagnosis and Management of Patients With Geographic Atrophy Secondary to Age-Related Macular Degeneration: A Delphi Consensus Exercise.

Geographic atrophy (GA) is a progressive and irreversible retinal disease with no comprehensive recommendations for diagnosis or monitoring. We used a Delphi approach to determine consensus in key areas around diagnosis and management of GA. A steering committee of eight retina specialists developed two sequential online surveys administered to eye care professionals (ECPs). Consensus was defined as agreement by ≥ 75% of respondents. Up to 177 ECPs from eight countries completed one or both surveys. Consensus was achieved in several topics related to diagnostic imaging, including the use of optical coherence tomography, and the urgent need for treatments and beneficial interventions to reduce the associated burden. Currently, low-vision aids and smoking cessation are considered the most beneficial interventions. We demonstrate consensus for diagnosis and management of patients with GA including best practices in patient identification and monitoring, and unmet needs. [Ophthalmic Surg Lasers Imaging Retina 2023;54:589-598.].

Does Age-Related Macular Degeneration (AMD) Treatment Influence Patient Falls and Mobility? A Systematic Review.

PURPOSE: Age-related macular degeneration (AMD), a leading cause of irreversible blindness, increases fall risk through impaired central vision. Falls place an enormous economic burden on healthcare systems. We hypothesized that AMD treatments may reduce patients' falls risk. This systematic review (ID #: 172623) synthesized the current understanding of wet and dry AMD treatments' impact on patient falls and mobility, connecting these two public health issues. METHODS: On April 17, 2020, PubMed, Scopus, CINAHL, and the Cochrane Central Register of Controlled Trials were queried. Clinical trials and observational studies were included, while non-English and non-primary studies were excluded. Two authors screened, extracted data, and assessed bias using RoB-2 and ROBINS-I. A third author served as a tie breaker. RESULTS: This database search resulted in 3,525 studies, with an additional 112 identified through bibliography review. Ten articles met eligibility criteria. Most studies featured the outcome of interest as a secondary outcome (n = 4) and patient-reported adverse events (n = 5), rather than a primary focus (n = 2). Ten out of the 11 outcomes had a moderate to serious risk of bias. No two studies used the same instrument to measure falls or mobility. CONCLUSION: Despite the potential positive impact of AMD treatments on patient falls and mobility, quality data on this relationship are lacking. This work underscores the need to broaden ophthalmologic research outcomes beyond visual parameters to include patient-centred, functional measures. Incorporating standardized methods to track falls and screen for difficulty with walking and balance would enable evaluation of AMD treatments on functional outcomes, potentially helping guide management.

Lateral gain is impaired in macular degeneration and can be targeted to restore vision in mice.

Macular degeneration is a leading cause of blindness. Treatments to rescue vision are currently limited. Here, we study how loss of central vision affects lateral feedback to spared areas of the human retina. We identify a cone-driven gain control mechanism that reduces visual function beyond the atrophic area in macular degeneration. This finding provides an insight into the negative effects of geographic atrophy on vision. Therefore, we develop a strategy to restore this feedback mechanism, through activation of laterally projecting cells. This results in improved vision in Cnga3-/- mice, which lack cone function, as well as a mouse model of geographic atrophy. Our work shows that a loss of lateral gain control contributes to the vision deficit in macular degeneration. Furthermore, in mouse models we show that lateral feedback can be harnessed to improve vision following retinal degeneration.

Survival of an HLA-mismatched, bioengineered RPE implant in dry age-related macular degeneration.

Cell-based therapies face challenges, including poor cell survival, immune rejection, and integration into pathologic tissue. We conducted an open-label phase 1/2a clinical trial to assess the safety and preliminary efficacy of a subretinal implant consisting of a polarized monolayer of allogeneic human embryonic stem cell-derived retinal pigmented epithelium (RPE) cells in subjects with geographic atrophy (GA) secondary to dry age-related macular degeneration. Postmortem histology from one subject with very advanced disease shows the presence of donor RPE cells 2 years after implantation by immunoreactivity for RPE65 and donor-specific human leukocyte antigen (HLA) class I molecules. Markers of RPE cell polarity and phagocytosis suggest donor RPE function. Further histologic examination demonstrated CD34+ structures beneath the implant and CD4+, CD68+, and FoxP3+ cells in the tissue. Despite significant donor-host HLA mismatch, no clinical signs of retinitis, vitreitis, vasculitis, choroiditis, or serologic immune response were detected in the deceased subject or any other subject in the study. Subretinally implanted, HLA-mismatched donor RPE cells survive, express functional markers, and do not elicit clinically detectable intraocular inflammation or serologic immune responses even without long-term immunosuppression.

Treatments for dry age-related macular degeneration: therapeutic avenues, clinical trials and future directions.

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the developed world. The identification of the central role of vascular endothelial growth factor (VEGF) in the pathogenesis of neovascular AMD and the introduction of anti-VEGF agents as gold-standard treatment, have drastically changed its prognosis-something yet to be seen in dry AMD. Several therapeutic avenues with a wide variability of targets are currently being investigated in dry AMD. The approaches being investigated to reduce the rate of disease progression include, (1) drugs with antioxidative properties, (2) inhibitors of the complement cascade, (3) neuroprotective agents, (4) visual cycle inhibitors, (5) gene therapy and (6) cell-based therapies. A number of early phase clinical trials have provided promising results, with many more ongoing and anticipated in the near future. In this review, we aim to provide an update of the interventional trials to date and future prospects for the treatment of dry AMD.