Management of neovascular age-related macular degeneration: current state-of-the-art care for optimizing visual outcomes and therapies in development

Topical Solution for Retinal Delivery: Bevacizumab and Ranibizumab Eye Drops in Anti-Aggregation Formula (AAF) in Rabbits

PURPOSE

Wet age-related macular degeneration (AMD) is a blinding retinal disease. Monthly intravitreal anti-VEGF antibody injections of bevacizumab (off-label) and ranibizumab (FDA approved) are the standard of care. Antibody aggregation may interfere with ocular absorption/distribution. This study assessed topical delivery of dilute antibodies to the posterior segment of rabbit eyes using a novel anti-aggregation formula (AAF).

METHODS

Bevacizumab, or biosimilar ranibizumab was diluted to 5 mg/ml in AAF. All rabbits were dosed twice daily. Substudy 1 rabbits (bevacizumab, 100 µl eye drops): Group 1 (bevacizumab/AAF, n = 6); Group 2 (bevacizumab/PBS, n = 7) and Vehicle control (AAF, n = 1). Substudy 2 rabbits (ranibizumab biosimilar/AAF, 50 µl eye drops): (ranibizumab biosimilar/AAF, n = 8). At 14.5 days, serum was drawn from rabbits. Aqueous, vitreous and retina samples were recovered from eyes and placed into AAF aliquots. Tissue analyzed using AAF as diluent.

RESULTS

Bevacizumab in AAF permeated/accumulated in rabbit aqueous, vitreous and retina 10 times more, than when diluted in PBS. AAF/0.1% hyaluronic acid eye drops, dosed twice daily, provided mean tissue concentrations (ng/g) in retina (29.50), aqueous (12.34), vitreous (3.46), and serum (0.28 ng/ml). Additionally, the highest concentration (ng/g) of ranibizumab biosimilar was present in the retina (18.0), followed by aqueous (7.82) and vitreous (1.47). Serum concentration was negligible (< 0.04 ng/ml). No irritation was observed throughout the studies.

CONCLUSIONS

Bevacizumab and ranibizumab, in an AAF diluent eye drop, can be delivered to the retina, by the twice daily dosing of a low concentration mAb formulation. This may prove to be an adjunct to intravitreal injections.

Purinergic signaling via P2X receptors and mechanisms of unregulated ATP release in the outer retina and age-related macular degeneration

Age-related macular degeneration (AMD) is a chronic and progressive inflammatory disease of the retina characterized by photoceptor loss and significant central visual impairment due to either choroidal neovascularization or geographic atrophy. The pathophysiology of AMD is complex and multifactorial, driven by a combination of modifiable and non-modifiable risk factors, molecular mechanisms, and cellular processes that contribute to overall disease onset, severity, and progression. Unfortunately, due to the structural, cellular, and pathophysiologic complexity, therapeutic discovery is challenging. While purinergic signaling has been investigated for its role in the development and treatment of ocular pathologies including AMD, the potential crosstalk between known contributors to AMD, such as the complement cascade and inflammasome activation, and other biological systems, such as purinergic signaling, have not been fully characterized. In this review, we explore the interactions between purinergic signaling, ATP release, and known contributors to AMD pathogenesis including complement dysregulation and inflammasome activation. We begin by identifying what is known about purinergic receptors in cell populations of the outer retina and potential sources of extracellular ATP required to trigger purinergic receptor activation. Next, we examine evidence in the literature that the purinergic system accelerates AMD pathogenesis leading to apoptotic and pyroptotic cell death in retinal cells. To fully understand the potential role that purinergic signaling plays in AMD, more research is needed surrounding the expression, distribution, functions, and interactions of purinergic receptors within cells of the outer retina as well as potential crosstalk with other systems. By determining how these processes are affected in the context of purinergic signaling, it will improve our understanding of the mechanisms that drive AMD pathogenesis which is critical in developing treatment strategies that prevent or slow progression of the disease.

The Impact of Residual Retinal Fluid Following Intravitreal Anti-Vascular Endothelial Growth Factor Therapy for Diabetic Macular Edema and Macular Edema Secondary to Retinal Vein Occlusion: A Systematic Review

The association between residual retinal fluid and visual acuity for diabetic macular edema (DME) and macular edema (ME) secondary to retinal vein occlusion (RVO) is not well established. We conducted a systematic literature search for peer-reviewed articles reporting on visual acuity stratified by subretinal fluid (SRF), intraretinal fluid (IRF), or any retinal fluid at final follow-up after intravitreal anti-vascular endothelial growth factor therapy injection for treatment of DME or ME secondary to RVO. Two observational studies on ME secondary to RVO and one study for DME found no significant differences between eyes with and without residual retinal fluid for final BCVA. One randomized controlled trial (RCT) found that eyes with residual retinal fluid had significantly worse final best-corrected visual acuity in ME secondary to RVO, whereas another RCT found no significant difference for DME. There is a paucity of evidence examining the impact of residual retinal fluid on visual acuity in DME and ME secondary to RVO. The limited evidence suggests that aggressive fluid resolution is worthwhile. [Ophthalmic Surg Lasers Imaging Retina 2023;54:50-58.].

Optimal approaches and criteria to treat-and-extend regimen implementation for Neovascular age-related macular degeneration: experts consensus in Taiwan

The management of neovascular age-related macular degeneration (nAMD) has taken a major stride forward with the advent of anti-VEGF agents. The treat-and-extend (T&E) approach is a refined management strategy, tailoring to the individual patient’s disease course and treatment outcome. To provide guidance to implementing anti-VEGF T&E regimens for nAMD in resource-limited health care systems, an advisory board was held to discuss and generate expert consensus, based on local and international guidelines, current evidence, as well as local experience and reimbursement policies. In the experts’ opinion, treatment of nAMD should aim to maximize and maintain visual acuity benefits while minimizing treatment burden. Based on current evidence, treatment could be initiated with 3 consecutive monthly injections. After the initial period, treatment interval may be extended by 2 or 4 weeks each time for the qualified patients (i.e. no BCVA loss ≥5 ETDRS letters and dry retina), and a maximum interval of 16 weeks is permitted. For patients meeting the shortening criteria (i.e. any increased fluid with BCVA loss ≥5 ETDRS letters, or presence of new macular hemorrhage or new neovascularization), the treatment interval should be reduced by 2 or 4 weeks each time, with a minimal interval of 4 weeks. Discontinuation of anti-VEGF may be considered for those who have received 2–3 consecutive injections spaced 16 weeks apart and present with stable disease. For these individuals, regular monitoring (e.g. 3–4 months) is recommended and monthly injections should be reinstated upon signs of disease recurrence.

Conformationally Constrained Peptides with High Affinity to the Vascular Endothelial Growth Factor

The design of efficient vascular endothelial growth factor (VEGF) inhibitors is a high-priority research area aimed at the treatment of pathological angiogenesis. Among other compounds, v114* has been identified as a potent VEGF-binding peptide. In order to improve the affinity to VEGF, we built a conformational constrain in its structure. To this aim, C^α-tetrasubstituted amino acid Aib was introduced into the N-terminal tail, peptide loop, or C-terminal helix. NMR studies confirmed the stabilization of the helical conformation in proximity to the Aib residue. We found that the induction of the N-terminal helical structure or stabilization of the C-terminal helix can noticeably increase the peptide affinity to the VEGF. These peptides efficiently inhibited VEGF-stimulated cell proliferation as well. The insertion of the non-proteinogenic Aib residue significantly enhanced the stability of the peptides in the vitreous environment. Thus, these Aib-containing peptides are promising candidates for the design of VEGF inhibitors with improved properties.

The complement system in age-related macular degeneration

Age-related macular degeneration (AMD) is a chronic and progressive degenerative disease of the retina, which culminates in blindness and affects mainly the elderly population. AMD pathogenesis and pathophysiology are incredibly complex due to the structural and cellular complexity of the retina, and the variety of risk factors and molecular mechanisms that contribute to disease onset and progression. AMD is driven by a combination of genetic predisposition, natural ageing changes and lifestyle factors, such as smoking or nutritional intake. The mechanism by which these risk factors interact and converge towards AMD are not fully understood and therefore drug discovery is challenging, where no therapeutic attempt has been fully effective thus far. Genetic and molecular studies have identified the complement system as an important player in AMD. Indeed, many of the genetic risk variants cluster in genes of the alternative pathway of the complement system and complement activation products are elevated in AMD patients. Nevertheless, attempts in treating AMD via complement regulators have not yet been successful, suggesting a level of complexity that could not be predicted only from a genetic point of view. In this review, we will explore the role of complement system in AMD development and in the main molecular and cellular features of AMD, including complement activation itself, inflammation, ECM stability, energy metabolism and oxidative stress.

Efficacy of a Treat-and-Extend Regimen With Ranibizumab in Patients With Neovascular Age-Related Macular Disease: A Randomized Clinical Trial

Importance

Although the Canadian Treat-and-Extend Analysis Trial With Ranibizumab in Patients With Neovascular Age-Related Macular Disease (CANTREAT) reported herein and the Treat and Extend study provided data to show noninferiority of treat-and-extend (T&E) at 12 months, to date there are few data on 24-month T&E trials compared with monthly dosing.

Objective

To compare the efficacy of ranibizumab using a T&E regimen to monthly dosing in treatment-naive patients with neovascular age-related macular degeneration (nAMD) after 24 months.

Design, Setting, and Participants

A randomized, open-label, multicenter, noninferiority intention-to-treat trial with a margin of -5 letters in best-corrected visual acuity (BCVA) from baseline to 12 months between groups was conducted at 27 treatment centers in Canada. Participants included 580 patients with treatment-naive choroidal neovascularization secondary to AMD. The study was conducted from May 8, 2013, to August 28, 2018, and data analysis was performed between August 29 and September 12, 2018.

Interventions

Patients with nAMD were randomized 1:1 to receive intravitreal ranibizumab, 0.5 mg, in either a T&E or monthly dosing regimen.

Main Outcomes and Measures

Mean change in BCVA in Early Treatment of Diabetic Retinopathy Study letters from baseline to month 24.

Results

Of the 580 randomized patients, 350 were women (60.3%) and 547 were white (94.3%). Mean (SD) age was 78.8 (7.8) years. By the end of month 24, 466 of the 580 randomized patients (80.3%) had completed the study and participants in the T&E arm received a mean of 17.6 injections compared with 23.5 injections for the monthly arm, for a difference of 5.9 injections and visits over 2 years (95% CI, 5.4-6.5; P < .001). The mean (SD) BCVA improvement was not worse with the T&E arm, 6.8 (14.1) letters vs 6.0 (12.6) letters, compared with the monthly arm (difference, 0.9; 95% CI, -1.6 to 3.3; P = .21). There was a gain of 15 or more letters in 25.5% of the T&E group and 23.1% of the monthly treatment group (difference, 2.4%; 95% CI, -6.8% to 11.6%; P = .59) and a loss of 15 or more letters in 6.5% of the T&E group and 5.8% of the monthly treatment group (difference, -0.7%; 95% CI, -9.9% to 8.5%; P = .85).

Conclusions and Relevance

These findings suggest that change in vision from baseline is not worse with a T&E compared with a monthly regimen of ranibizumab for nAMD through 24 months, achieving clinically meaningful improvements in BCVA despite fewer injections and visits.

Trial Registration

ClinicalTrials.gov identifier: NCT02103738.

Collagen-based scaffolds with infused anti-VEGF release system as potential cornea substitute for high-risk keratoplasty: A preliminary in vitro evaluation

Currently the only widely accepted corneal blindness treatment is human donor cornea transplantation. However, increasing shortage of donor corneas as well as high risk of rejection in some corneal diseases remain two major problems, which limit the success of corneal transplantation. Corneal neovascularization is considered as one of the main risk factors of graft failure. Different cell-free biosynthetic scaffolds fabricated from collagens or collagen-like peptides are being tested as donor cornea substitutes (DCS). Here, we report for the first-time composite biosynthetic DCS with integrated sustained release system of anti-VEGF drug, bevacizumab and their preliminary in vitro validation. We have tethered gold nanoparticles with bevacizumab and integrated into a collagen-based cell-free hydrogel scaffold. Developed grafts preserved good optical properties and were confirmed not toxic to human corneal epithelial cells. Bevacizumab has been shown to constantly releasing from the DCS up to 3 weeks and preserved its anti-angiogenic properties. These results provide background for further use of infused composite biosynthetic DCS with integrated nanosystem of bevacizumab sustained release in corneal disease accompanied by neovascularisation where conventional corneal transplantation might fail.

Prognostic Factors and Long-term Surgical Outcomes for Exudative Age-related Macular Degeneration with Breakthrough Vitreous Hemorrhage

Purpose

We sought to evaluate the long-term outcomes for patients with exudative age-related macular degeneration (AMD) undergoing vitrectomy for breakthrough vitreous hemorrhage and to investigate possible prognostic factors.

Methods

Consecutive patients treated at two high-volume referral-based tertiary hospitals between July 2006 and December 2019 were retrospectively reviewed. Surgery was performed using the standard three-port vitrectomy. The primary outcome was the change in best-corrected visual acuity (BCVA) over long-term follow-up, while secondary outcomes included the assessment of possible prognostic factors.

Results

Among 50 eyes from 50 patients included in this study, 23 (46%) were diagnosed with polypoidal choroidal vasculopathy (PCV) and 27 (54%) were diagnosed with neovascular AMD. Preoperative vision at the time of vitreous hemorrhage onset was 20 / 3,027 (logarithm of the minimum angle of resolution [logMAR], 2.18 ± 0.34). At 12 months after surgery, the mean BCVA improved to 20 / 873 (logMAR, 1.64 ± 0.76; p < 0.001). At 24 months, the BCVA was 20 / 853 (logMAR, 1.63 ± 0.75; p < 0.001). Univariate analysis revealed that older age (odds ratio [OR], 0.879; p = 0.007] and the presence of submacular hemorrhage (OR, 0.081; p = 0.022) were factors associated with a poor 2-year visual outcome. Multivariable regression showed that older age (OR, 0.876; p = 0.026) and neovascular AMD (as compared with PCV) (OR, 0.137; p = 0.014) were significant negative factors influencing the 2-year visual outcome. The mean injection interval prior to vitrectomy was 4.53 months, which extended to 27.64 months after vitrectomy (p = 0.028).

Conclusions

Younger age, the absence of submacular hemorrhage, and PCV type were associated with a favorable 2-year visual outcome after vitrectomy for vitreous hemorrhage in patients with exudative AMD. Overall, vitrectomy resulted in improved visual acuity and patients showed a decreased need for anti-vascular endothelial growth factor therapy thereafter.

Therapeutic Potential of the Ranibizumab Port Delivery System in the Treatment of AMD: Evidence to Date

Age-related macular degeneration (AMD) is one of the leading causes of blindness in older adults worldwide. The advent of intravitreal neutralization of vascular endothelial growth factor (VEGF) has revolutionized the management of patients with neovascular AMD, but current anti-VEGF therapies carry a high threshold of patient burden. The ranibizumab port delivery system (PDS) is an implanted, refillable reservoir that continuously supplies the anti-VEGF medication ranibizumab directly into the vitreous, eliminating the need for frequent intravitreal injections. It has most recently been evaluated in the Phase II LADDER trial demonstrating the efficacy and safety of the PDS, with Phase III trials currently underway. This review presents both the promise and drawbacks of the PDS in the treatment of AMD from the current literature.

Comparison of vision-related quality of life and mental health between congenital and acquired low-vision patients

Purpose

To evaluate the impact of the age of onset of low vision on patients’ vision-related quality of life (VR-QoL) and mental health.

Methods

Low-vision patients who visited Chung-Ang University hospital from January 2012 to December 2014 were included. Patients were divided into the congenital low-vision (CLV) and acquired low-vision (ALV) groups according to the age of disease onset. People with normal visual function comprised the control group. VR-QoL was estimated with the National Eye Institute Visual Function Questionnaire (NEI VFQ-25), while mental health was assessed through the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI). The mean scores of each questionnaire were compared between the groups in independent t-tests.

Results

Overall, 125 low-vision patients (55 CLV and 70 ALV) and 71 control subjects were included. Although the subscale and composite scores of the NEI VFQ-25 were lower in the ALV group than in the CLV group, the differences were not significant. However, the BDI and BAI scores were significantly higher in the ALV group than in the CLV group (12.07 ± 11.97 vs. 7.67 ± 9.04, P = 0.021; 9.11 ± 10.51 vs. 5.69 ± 6.85, P = 0.030, respectively). Also, the number of patients requiring expert consultation for depression was higher in the ALV group than in the CLV group (P = 0.010).

Conclusion

ALV patients have more vulnerable mental health states than CLV patients. Therefore, assessment of the age of onset of low vision and mental health plays a critical role in successful rehabilitation.

Macular Atrophy of the Retinal Pigment Epithelium in Patients with Neovascular Age-Related Macular Degeneration: What is the Link? Part I: A Review of Disease Characterization and Morphological Associations

Introduction

The purpose of this review was to explore the potential link between macular atrophy (MA) of the retinal pigment epithelium in patients with neovascular age-related macular degeneration (nAMD) with the disease characteristics and morphological features.

Methods

To this end, we performed a search of peer-reviewed articles published on the PubMed database and included all relevant papers. We then examined these papers for possible risk factors for MA development in the context of nAMD treated with anti-vascular endothelial growth factor drugs, as well as possible protective factors.

Results

Our review of the relevant publications revealed that areas of MA can be directly visualized through multiple imaging modalities. Associations have been identified between MA of the retinal pigment epithelium and choroidal neovascular membrane characteristics, intra- and subretinal fluid, pigment epithelial detachment, choroidal thickness, subretinal hyperreflective material, outer retinal tubulations, hemorrhage, subretinal drusenoid deposits, refractile drusen, hyperreflective foci, retinal angiomatous proliferation, polypoidal choroidal vasculopathy, geographic atrophy in the fellow eye, genetic factors, and age.

Conclusion

The findings of this review indicate that a multimodal approach is recommended for the assessment of MA. The conclusions drawn to date on the correlation between MA development or progression of MA and specific risk factors and possible protective factors are mixed. More clinical research is needed to reach a better understanding of this association.

Foxp3+ Tregs are recruited to the retina to repair pathological angiogenesis

Neovascular retinopathies are major causes of vision loss; yet treatments to prevent the condition are inadequate. The role of regulatory T cells in neovascular retinopathy is unknown. Here we show that in retinopathy regulatory T cells are transiently increased in lymphoid organs and the retina, but decline when neovascularization is established. The decline is prevented following regulatory T cells expansion with an IL-2/anti-IL-2 mAb complex or the adoptive transfer of regulatory T cells. Further, both approaches reduce vasculopathy (vaso-obliteration, neovascularization, vascular leakage) and alter the activation of Tmem119⁺ retinal microglia. Our in vitro studies complement these findings, showing that retinal microglia co-cultured with regulatory T cells exhibit a reduction in co-stimulatory molecules and pro-inflammatory mediators that is attenuated by CTLA-4 blockade. Collectively, we demonstrate that regulatory T cells are recruited to the retina and, when expanded in number, repair the vasculature. Manipulation of regulatory T cell numbers is a previously unrecognized, and promising avenue for therapies to prevent blinding neovascular retinopathies.

The local immune responses in the eye are attenuated to preserve sight. Surprisingly, Deliyanti et al. show that regulatory T cells (Tregs) take an active role in protecting the eye from neovascularization in oxygen-induced retinopathy, and that interventions that augment the retinal Treg numbers reduce neovascular retinopathy in mice.

Spironolactone as an Adjunctive Treatment in Neovascular Age-Related Macular Degeneration

Neovascular age-related macular degeneration (AMD) is a potentially sight-threatening condition. The current standard-of-care treatment regimen is serial intravitreal antivascular endothelial growth factor injections. While these typically have great success, they do carry exceptional treatment burden on the patient, cost burden due to their required frequency of use, and the risk of endophthalmitis, which can be devastating. This case report explores an alternative potential option as a treatment adjunct for neovascular AMD (nAMD), and identifies some of the overlap between nAMD and central serous chorioretionpathy. Future research is needed to better understand the role of mineralocorticoid receptor antagonist treatment in this disease spectrum.

Recent perspectives on the delivery of biologics to back of the eye

INTRODUCTION

Biologics are generally macromolecules, large in size with poor stability in biological environments. Delivery of biologics to tissues at the back of the eye remains a challenge. To overcome these challenges and treat posterior ocular diseases, several novel approaches have been developed. Nanotechnology-based delivery systems, like drug encapsulation technology, macromolecule implants and gene delivery are under investigation. We provide an overview of emerging technologies for biologics delivery to back of the eye tissues. Moreover, new biologic drugs currently in clinical trials for ocular neovascular diseases have been discussed. Areas covered: Anatomy of the eye, posterior segment disease and diagnosis, barriers to biologic delivery, ocular pharmacokinetic, novel biologic delivery system Expert opinion: Anti-VEGF therapy represents a significant advance in developing biologics for the treatment of ocular neovascular diseases. Various strategies for biologic delivery to posterior ocular tissues are under development with some in early or late stages of clinical trials. Despite significant progress in the delivery of biologics, there is unmet need to develop sustained delivery of biologics with nearly zero-order release kinetics to the back of the eye tissues. In addition, elevated intraocular pressure associated with frequent intravitreal injections of macromolecules is another concern that needs to be addressed.

Management of Neovascular Age-related Macular Degeneration: A Review on Landmark Randomized Controlled Trials

In the last decade, a number of prospective clinical trials with carefully designed study protocols have been conducted for the treatment of neovascular age-related macular degeneration (AMD). These landmark clinical trials such as ANCHOR and MARINA and, more recently, the Comparison of AMD Treatment Trials and VIEW studies have revolutionized the management of neovascular AMD. While AMD continues to remain a leading cause of severe visual loss worldwide, advances in pharmacotherapeutics have led to substantial improvements in the outcome of these patients. The introduction of anti-vascular endothelial growth factor agents has resulted in improvement of visual outcomes and has had a positive impact on the quality of life among elderly population. While the contemporary management of neovascular AMD has been successful in tremendously reducing the visual morbidity, the financial burden of therapy has increased exponentially. To overcome these challenges, newer pharmacologic agents are evaluated for their efficacy and safety in AMD. Ground-breaking advances in bench to bedside research have led to discovery of new pathways that appear to be viable targets for preventing visual loss in AMD. In this review, study designs and results of landmark clinical trials in AMD from the past decade have been summarized.

Optogenetics for neurodegenerative diseases

Neurodegenerative diseases are devastating conditions that lead to progressive degeneration of neurons. Neurodegeneration may result in ataxia, dementia, and muscle atrophies, etc. Despite enormous research efforts that have been made, there is lack of effective therapeutic interventions for most of these diseases. Optogenetics is a recently developed novel technique that combines optics and genetics to modulate the activity of specific neurons. Optogenetics has been implemented in various studies including neuropsychiatric disorders and neurodegenerative diseases. This review focuses on the recent advance in using this technique for the studies of common neurodegenerative diseases.