Vascular Endothelial Growth Factor Antagonists: Promising Players in the Treatment of Neovascular Age-Related Macular Degeneration

Vascular Endothelial Growth Factor C and D Signaling Pathways as Potential Targets for the Treatment of Neovascular Age-Related Macular Degeneration: A Narrative Review

The development of treatments targeting the vascular endothelial growth factor (VEGF) signaling pathways have traditionally been firstly investigated in oncology and then advanced into retinal disease indications. Members of the VEGF family of endogenous ligands and their respective receptors play a central role in vasculogenesis and angiogenesis during both development and physiological homeostasis. They can also play a pathogenic role in cancer and retinal diseases. Therapeutic approaches have mostly focused on targeting VEGF-A signaling; however, research has shown that VEGF-C and VEGF-D signaling pathways are also important to the disease pathogenesis of tumors and retinal diseases. This review highlights the important therapeutic advances and the remaining unmet need for improved therapies targeting additional mechanisms beyond VEGF-A. Additionally, it provides an overview of alternative VEGF-C and VEGF-D signaling involvement in both health and disease, highlighting their key contributions in the multifactorial pathophysiology of retinal disease including neovascular age-related macular degeneration (nAMD). Strategies for targeting VEGF-C/-D signaling pathways will also be reviewed, with an emphasis on agents currently being developed for the treatment of nAMD.

Inefficacy of anti-VEGF therapy reflected in VEGF-mediated photoreceptor degeneration

Retinal neovascularization (RNV) is primarily driven by vascular endothelial growth factor (VEGF). However, current anti-VEGF therapies are limited by short half-lives and repeated injections, which reduce patient quality of life and increase medical risks. Additionally, not all patients benefit from anti-VEGF monotherapy, and some problems, such as unsatisfactory vision recovery, persist after long-term treatment. In this study, we constructed a recombinant adeno-associated virus (AAV), AAV2-SPLTH, which encodes an anti-VEGF antibody similar to bevacizumab, and assessed its effects in a doxycycline-induced Tet-opsin-VEGFA mouse model of RNV. AAV2-SPLTH effectively inhibited retinal leakage, RNV progression, and photoreceptor apoptosis in a Tet-opsin-VEGF mouse model. However, proteomic sequencing showed that AAV2-SPLTH failed to rescue the expression of phototransduction-related genes, which corresponded to reduced photoreceptor cell numbers. This study suggests that anti-VEGF monotherapy can significantly inhibit RNV to some extent but may not be enough to save visual function in the long term.

Cognitive bias evaluation on the choice of treatment in common retinal disorders among retina specialists in 2023

PURPOSE

The study aimed to discern the intent to treat with the therapeutic agents prescribed first or second line in the following eye conditions: neovascular age-related macular Degeneration (nAMD), diabetic macular edema (DME), retinal vein occlusion (RVO), and myopic maculopathy with choroidal neovascularization (MMNV). The study also aimed to distinguish the ophthalmologists' intended treatment for their patients from those that they would prescribe for themselves if they were affected by the above macular conditions.

METHODS

The study utilized an online survey of 243 French ophthalmologists practicing medical retina, with males accounting for 54.3% of the participants. Data was obtained using a questionnaire that focused on the ophthalmologists' experience with various agents as well as their first and second line choices for nAMD, DME, RVO, and MMNV.

RESULTS

The vast majority of French ophthalmologists (99%) had experience with the most widely used anti-vascular endothelial growth factors (anti-VEGFs); ranibizumab, bevacizumab, and aflibercept. Fewer than 8% reported experience with anti-VEGF drug reservoirs, biosimilars, or faricimab. The study findings also showed ranibizumab and aflibercept as the commonly prescribed first line choices for the above-mentioned ocular conditions. For the second line choice, the study showed that aflibercept and dexamethasone intravitreal implants were the most common across the four retinal conditions studied. The only difference in intent to treat for "patients" versus "yourself" was for biosimilars (0% to 0.8%, P=0.001).

CONCLUSION

The findings regarding the first and second line choices for the mentioned ocular disorders were found to agree with the findings of published literature currently used in practice, with a tendency to prefer ranibizumab as first line therapy for neovascular disorders and aflibercept as first line therapy for macular edema. In addition, there were no differences between choices for first and second line therapy for patients vs. ophthalmologists.

An update on the latest strategies in retinal drug delivery

INTRODUCTION

Retinal drug delivery has witnessed significant advancements in recent years, mainly driven by the prevalence of retinal diseases and the need for more efficient and patient-friendly treatment strategies.

AREAS COVERED

Advancements in nanotechnology have introduced novel drug delivery platforms to improve bioavailability and provide controlled/targeted delivery to specific retinal layers. This review highlights various treatment options for retinal diseases. Additionally, diverse strategies aimed at enhancing delivery of small molecules and antibodies to the posterior segment such as implants, polymeric nanoparticles, liposomes, niosomes, microneedles, iontophoresis and mixed micelles were emphasized. A comprehensive overview of the special technologies currently under clinical trials or already in the clinic was provided.

EXPERT OPINION

Ideally, drug delivery system for treating retinal diseases should be less invasive in nature and exhibit sustained release up to several months. Though topical administration in the form of eye drops offers better patient compliance, its clinical utility is limited by nature of the drug. There is a wide range of delivery platforms available, however, it is not easy to modify any single platform to accommodate all types of drugs. Coordinated efforts between ophthalmologists and drug delivery scientists are necessary while developing therapeutic compounds, right from their inception.

Compounding engineered mesenchymal stem cell-derived exosomes: A potential rescue strategy for retinal degeneration

The prevalence of retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, has been increasing globally and is linked to the aging population and improved life expectancy. These diseases are characterized by chronic, progressive neuronal damage or depletion of the photoreceptor cells in the retina, and limited effective treatment options are currently available. Mesenchymal stem cell-derived exosomes (MSC-EXOs) containing cytokines, growth factors, lipids, mRNA, and miRNA, which act as mediators of intercellular communication transferring bioactive molecules to recipient cells, offer an appealing, non-cellular nanotherapeutic approach for retinal degenerative diseases. However, treatment specificity is compromised due to their high heterogeneity in size, content, functional effects, and parental cellular source. To improve this, engineered MSC-EXOs with increased drug-loading capacity, targeting ability, and resistance to bodily degradation and elimination have been developed. This review summarizes the recent advances in miRNAs of MSC-EXOs as a treatment for retinal degeneration, discussing the strategies and methods for engineering therapeutic MSC-EXOs. Notably, to address the single functional role of engineered MSC-EXOs, we propose a novel concept called "Compound Engineered MSC-EXOs (Co-E-MSC-EXOs)" along with its derived potential therapeutic approaches. The advantages and challenges of employing Co-E-MSC-EXOs for retinal degeneration in clinical applications, as well as the strategies and issues related to them, are also highlighted.

New Perspectives in Stem Cell Transplantation and Associated Therapies to Treat Retinal Diseases: From Gene Editing to 3D Bioprinting

Inherited and non-inherited retinopathies can affect distinct cell types, leading to progressive cell death and visual loss. In the last years, new approaches have indicated exciting opportunities to treat retinopathies. Cell therapy in retinitis pigmentosa, age-related macular disease, and glaucoma have yielded encouraging results in rodents and humans. The first two diseases mainly impact the photoreceptors and the retinal pigmented epithelium, while glaucoma primarily affects the ganglion cell layer. Induced pluripotent stem cells and multipotent stem cells can be differentiated in vitro to obtain specific cell types for use in transplant as well as to assess the impact of candidate molecules aimed at treating retinal degeneration. Moreover, stem cell therapy is presented in combination with newly developed methods, such as gene editing, Müller cells dedifferentiation, sheet & drug delivery, virus-like particles, optogenetics, and 3D bioprinting. This review describes the recent advances in this field, by presenting an updated panel based on cell transplants and related therapies to treat retinopathies.

Intravitreal OZURDEX vs. Intravitreal Bevacizumab for Diabetic Macular Edema: A Comprehensive Review

This comprehensive review examines the efficacy, safety, and implications of intravitreal OZURDEX and intravitreal bevacizumab in treating diabetic macular edema (DME). DME is a common complication of diabetes mellitus and a leading cause of vision loss. OZURDEX, through sustained release of dexamethasone, targets inflammation and vascular permeability, while bevacizumab inhibits vascular endothelial growth factor (VEGF), reducing angiogenesis. However, differences in safety profiles exist, with OZURDEX associated with an increased risk of intraocular pressure elevation and cataract formation and bevacizumab potentially carrying systemic risks. The choice between these treatments should be individualized, considering patient preferences, ocular and systemic comorbidities, and cost-effectiveness. Collaboration among healthcare providers is essential for the comprehensive management of DME. Future research should focus on long-term comparative studies, predictors of treatment response, and exploration of novel therapeutic targets to optimize treatment outcomes for patients with DME.

Immune System, Inflammation and Autoantigens in Wet Age-Related Macular Degeneration: Pathological Significance and Therapeutic Importance

Wet age-related macular degeneration (wAMD) is a chronic inflammation-associated neurodegenerative disease affecting the posterior part of the eye in the aging population. Aging results in the reduced functionality of cells and tissues, including the cells of the retina. Initiators of a chronic inflammatory and pathologic state in wAMD may be a result of the accumulation of inevitable metabolic injuries associated with the maintenance of tissue homeostasis from a young age to over 50. Apart from this, risk factors like smoking, genetic predisposition, and failure to repair the injuries that occur, alongside attempts to rescue the hypoxic outer retina may also contribute to the pathogenesis. Aging of the immune system (immunosenescence) and a compromised outer blood retinal barrier (BRB) result in the exposure of the privileged milieu of the retina to the systemic immune system, further increasing the severity of the disease. When immune-privileged sites like the retina are under pathological stress, certain age- and disease-related conditions may necessitate assistance from cells distant from the resident ones to help restore the functionality of the tissue. As a necessary part of tissue repair, inflammation is a major response to disease and recruits immune cells to the site of damage. We suspect that the specific reparative inflammatory responses are controlled by an autoantigen-T cell-mediated mechanism, a process that may be hindered in wAMD.

Anti-VEGF Drugs in Age-Related Macular Degeneration: A Focus on Dosing Regimen-Related Safety and Efficacy

Age-related macular degeneration (AMD) is one of the main causes of visual impairment and severe visual loss, and can progress to two advanced forms-neovascularization and atrophic. The field of anti-AMD drugs has undergone huge developments in recent years, from single-target intravitreal administration to current clinical studies with multi-target and non-invasive agents, offering interesting new pharmacological opportunities for the treatment of this disease. Hence, we summarize some of the approved anti-vascular endothelial growth factor (VEGF) drugs for neovascular AMD, especially their structural characteristics, clinical manifestations, dosing regimens, and safety issues of the anti-VEGF drugs highlighted. In addition, advances in atrophic AMD drug research are also briefly described.

An Update on Strategies to Deliver Protein and Peptide Drugs to the Eye

In the past few decades, advancements in protein engineering, biotechnology, and structural biochemistry have resulted in the discovery of various techniques that enhanced the production yield of proteins, targetability, circulating half-life, product purity, and functionality of proteins and peptides. As a result, the utilization of proteins and peptides has increased in the treatment of many conditions, including ocular diseases. Ocular delivery of large molecules poses several challenges due to their high molecular weight, hydrophilicity, unstable nature, and poor permeation through cellular and enzymatic barriers. The use of novel strategies for delivering protein and peptides such as glycoengineering, PEGylation, Fc-fusion, chitosan nanoparticles, and liposomes have improved the efficacy, safety, and stability, which consequently expanded the therapeutic potential of proteins. This review article highlights various proteins and peptides that are useful in ocular disorders, challenges in their delivery to the eye, and strategies to enhance ocular bioavailability using novel delivery approaches. In addition, a few futuristic approaches that will assist in the ocular delivery of proteins and peptides were also discussed.

[Vitreoretinal surgery in age-related macular degeneration]

The structure of the vitreous body, its interaction with the retinal surface and tractive alterations of the vitreoretinal interface may play a role in the pathogenesis and the development of age-related macular degeneration (AMD). From clinical trials it can be concluded that posterior vitreous detachment (PVD) or vitreous removal may protect against the development of neovascular AMD. Vitreomacular adhesions may promote neovascular AMD and may have an impact on the efficacy and frequency of intravitreal vascular endothelial growth factor (VEGF) inhibition. Therefore, vitreomacular surgery may be considered as a treatment option in selected cases. Peeling of epimacular membranes and the internal limiting membrane (ILM) may contribute to stabilizing visual acuity and reducing the treatment burden of current intravitreal pharmacotherapy. At present, surgical interventions in AMD are mainly performed in cases of submacular hemorrhage involving the fovea. The treatment is not standardized and consists of liquefaction of the blood using recombinant tissue plasminogen activator (rTPA) and its pneumatic displacement, potentially combined with VEGF inhibition. Other submacular surgical strategies, such as choroidal neovascularization (CNV) extraction, macular translocation or transplantation of retinal pigment epithelium (RPE) are currently limited to selected cases as a salvage treatment; however, the development of these submacular surgical interventions has formed the basis for new approaches in the treatment of dry and neovascular AMD including submacular or intravitreal gene and stem cell therapy.

Repurposing of antiangiogenic agents for treatment of vascular anomalies

Vascular anomalies (VA) are developmental anomalies of veins, arteries, lymphatics or capillaries thought to be caused by mutations in genes that drive angiogenesis. Treatments targeting these genes are limited. We review the literature for conventional medications and products from traditional medicine cultures that have been found to have antiangiogenic activity. Fewer than 50 drugs with credible human activity in VA were identified and include β blockers, monoclonal antibodies, microtubule inhibitors, multi-kinase inhibitors, PIK3CA- and RAS-MAPK pathway inhibitors, and thalidomides. Other drug categories of potential interest are ACE-inhibitors, antifungals, antimalarials, MMP9-inhibitors, and over-the-counter compounds used in Eastern traditional medicine. Low toxicity for some offers the possibility of combined use with known effective agents. In addition to already familiar drugs, others with antiangiogenic capabilities already in use in children or adults may deserve further attention for repurposing for VA.

A new era in posterior segment ocular drug delivery: Translation of systemic, cell-targeted, dendrimer-based therapies

Vision impairment and loss due to posterior segment ocular disorders, including age-related macular degeneration and diabetic retinopathy, are a rapidly growing cause of disability globally. Current treatments consist primarily of intravitreal injections aimed at preventing disease progression and characterized by high cost and repeated clinic visits. Nanotechnology provides a promising platform for drug delivery to the eye, with potential to overcome anatomical and physiological barriers to provide safe, effective, and sustained treatment modalities. However, there are few nanomedicines approved for posterior segment disorders, and fewer that target specific cells or that are compatible with systemic administration. Targeting cell types that mediate these disorders via systemic administration may unlock transformative opportunities for nanomedicine and significantly improve patient access, acceptability, and outcomes. We highlight the development of hydroxyl polyamidoamine dendrimer-based therapeutics that demonstrate ligand-free cell targeting via systemic administration and are under clinical investigation for treatment of wet age-related macular degeneration.

Randomized Trial of Biosimilar XSB-001 versus Reference Ranibizumab in Patients with Neovascular Age-Related Macular Degeneration

OBJECTIVE

To evaluate the efficacy, safety, and immunogenicity of a ranibizumab biosimilar candidate (XSB-001) versus reference product (Lucentis) for neovascular age-related macular degeneration (nAMD).

DESIGN

Phase III, multicenter, randomized, double-masked, parallel-group study.

PARTICIPANTS

Patients with nAMD.

METHODS

Eligible patients were randomized (1:1) to receive intravitreal injections of XSB-001 or reference ranibizumab (0.5 mg [0.05 ml]) in the study eye once every 4 weeks for 52 weeks. Efficacy and safety assessments continued through 52 weeks of treatment.

MAIN OUTCOME MEASURES

Primary end point was change from baseline in best-corrected visual acuity (BCVA) by ETDRS letters at week 8. Biosimilarity was concluded if the 2-sided 90% confidence interval (CI) (United States) or 95% CI (rest of world) for the difference in least-squares (LS) mean change in BCVA at week 8 between treatment groups was within the predefined equivalence margin of ± 3.5 letters.

RESULTS

In total, 582 patients (n = 292 XSB-001, n = 290 reference ranibizumab) were randomized. Mean age was 74.1 years, most patients (85.2%) were White, and 55.8% were women. Mean BCVA score at baseline was 61.7 and 61.5 ETDRS letters in the XSB-001 and reference ranibizumab groups, respectively. At week 8, the LS mean (standard error [SE]) change in BCVA from baseline was 4.6 (0.5) ETDRS letters in the XSB-001 group and 6.4 (0.5) letters in the reference ranibizumab group (LS mean [SE] treatment difference: -1.8 [0.7] ETDRS letters; 90% CI, -2.9 to -0.7; 95% CI, -3.1 to -0.5). The 90% CI and 95% CI for LS mean difference in change from baseline were within the predefined equivalence margin. At week 52, LS mean (SE) change in BCVA was 6.4 (0.8) and 7.8 (0.8) letters, respectively (LS mean [SE] treatment difference, -1.5 [1.1] ETDRS letters; 90% CI, -3.3 to 0.4; 95% CI, -3.6 to 0.7). There were no clinically meaningful differences between treatments in anatomical, safety, or immunogenicity end points through week 52.

CONCLUSIONS

XSB-001 demonstrated biosimilarity to reference ranibizumab in patients with nAMD. Treatment with XSB-001 for 52 weeks was generally safe and well tolerated, with a safety profile similar to the reference product.

FINANCIAL DISCLOSURE(S)

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

Intravitreal Anti-Vascular Endothelial Growth Factor Therapies for Retinal Disorders

Vascular endothelial growth factors (VEGFs) are key mediator of retinal and choroidal neovascularization as well as retinal vascular leakage leading to macular edema. As such, VEGF plays an important role in mediating visually significant complications associated with common retinal disorders such as diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Various drugs that inhibit vascular endothelial growth factors (anti-VEGF therapies) have been developed to minimize vision loss associated with these disorders. These drugs are injected into the vitreous cavity in a clinic setting at regular intervals. This article provides an overview of the various anti-VEGF drugs used in ophthalmology and the common retinal conditions that benefit from this therapy.

Targeting angiogenesis in oncology, ophthalmology and beyond

Angiogenesis is an essential process in normal development and in adult physiology, but can be disrupted in numerous diseases. The concept of targeting angiogenesis for treating diseases was proposed more than 50 years ago, and the first two drugs targeting vascular endothelial growth factor (VEGF), bevacizumab and pegaptanib, were approved in 2004 for the treatment of cancer and neovascular ophthalmic diseases, respectively. Since then, nearly 20 years of clinical experience with anti-angiogenic drugs (AADs) have demonstrated the importance of this therapeutic modality for these disorders. However, there is a need to improve clinical outcomes by enhancing therapeutic efficacy, overcoming drug resistance, defining surrogate markers, combining with other drugs and developing the next generation of therapeutics. In this Review, we examine emerging new targets, the development of new drugs and challenging issues such as the mode of action of AADs and elucidating mechanisms underlying clinical benefits; we also discuss possible future directions of the field.

Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them

An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.

Recent advances and future prospects: current status and challenges of the intraocular injection of drugs for vitreoretinal diseases

Effective drug therapy for vitreoretinal disease is a major challenge in the field of ophthalmology; various protective systems, including anatomical and physiological barriers, complicate drug delivery to precise targets. However, as the eye is a closed cavity, it is an ideal target for local administration. Various types of drug delivery systems have been investigated that take advantage of this aspect of the eye, enhancing ocular permeability and optimizing local drug concentrations. Many drugs, mainly anti-VEGF drugs, have been evaluated in clinical trials and have provided clinical benefit to many patients. In the near future, innovative drug delivery systems will be developed to avoid frequent intravitreal administration of drugs and maintain effective drug concentrations for a long period of time. Here, we review the published literature on various drugs and administration routes and current clinical applications. Recent advances in drug delivery systems are discussed along with future prospects.

Predictive value of pigment epithelial detachment markers for visual acuity outcomes in neovascular age-related macular degeneration

BACKGROUND

To determine the predictive value of quantitative morphological parameters for pigment epithelial detachment (PED) of neovascular age-related macular degeneration (nAMD) patients.

METHODS

One eye from each of 159 patients with nAMD were studied. Polypoidal choroidal vasculopathy (PCV) group included 77 eyes, and non-PCV group 82. Patients received conbercept 0.05 ml (0.5 mg) in a 3 + ProReNata (PRN) treatment regimen. Correlations between retinal morphologic parameters at baseline and best-corrected visual acuity (BCVA) gain at 3 or 12 months after treatment (structure-function correlations) were assessed. Optical coherence tomography (OCT) scans were used to assess retinal morphologic features including intraretinal cystoid fluid (IRC), subretinal fluid (SRF), PED or PED type (PEDT), and vitreomacular adhesion (VMA). Greatest height (PEDH) and width of PED (PEDW), and volume of PED (PEDV) at baseline were also measured.

RESULTS

For non-PCV group, BCVA gain from 3 or 12 months after treatment was negatively correlated with PEDV at baseline (r = -0.329, -0.312, P = 0.027, 0.037). BCVA gain at 12 months after treatment was negatively correlated with PEDW at baseline (r = -0.305, P = 0.044). For PCV group, there were no correlations with PEDV, PEDH, PEDW, and PEDT in BCVA gain between baseline and 3 or 12 months after treatment (P > 0.05). SRF, IRC, VMA at baseline did not correlate with short-term and long-term BCVA gain in patients with nAMD (P > 0.05).

CONCLUSION

For patients with non-PCV, PEDV at baseline was negatively correlated with short-term and long-term BCVA gain, and PEDW was negatively correlated with long-term BCVA gain. On the contrary, quantitative morphological parameters for PED at baseline had no correlation with BCVA gain in patients with PCV.

Identifying and addressing common contributors to nonadherence with ophthalmic medical therapy

PURPOSE OF REVIEW

To discuss common reasons for nonadherence and review existing and emerging options to reduce nonadherence with ocular medical therapy and optimize therapeutic outcomes.

RECENT FINDINGS

Nonadherence can arise from patient-related issues (e.g. physical, cognitive) and healthcare-related issues (e.g. cost, access to care). Multiple strategies have been developed and evaluated to overcome these barriers to adherence. Identifying nonadherence and its cause(s) facilitates the development of strategies to overcome it.

SUMMARY

Many common causes of nonadherence can be mitigated through a variety of strategies presented.

Ocular barriers as a double-edged sword: preventing and facilitating drug delivery to the retina

In recent decades, the growing of the aging population in the world brings increasingly heavy burden of vision-threatening retinal diseases. One of the biggest challenges in the treatment of retinal diseases is the effective drug delivery to the diseased area. Due to the existence of multiple anatomical and physiological barriers of the eye, commonly used oral drugs or topical eye drops cannot effectively reach the retinal lesions. Innovations in new drug formulations and delivery routes have been continuously applied to improve current drug delivery to the back of the eye. Unique ocular anatomical structures or physiological activities on these ocular barriers, in turn, can facilitate drug delivery to the retina if compatible formulations or delivery routes are properly designed or selected. This paper focuses on key barrier structures of the eye and summarizes advances of corresponding drug delivery means to the retina, including various local drug delivery routes by invasive approaches, as well as systemic eye drug delivery by non-invasive approaches.

Controversies and Disparities in the Management of Age-Related Macular Degeneration

Age-related macular degeneration is a leading cause of blindness in patients aged 50 years and older. Prior to the 21^st century, there were no effective treatments for this devastating disease. However, the last 20 years have heralded the development of treatments for both the nonexudative and exudative forms. The invention of AREDS vitamin supplements and anti-VEGF therapies forever changed the treatment of dry and wet age-related macular degeneration, respectively. The rapid adoption and expansion of these vision preserving treatments has created controversy regarding their cost, burden of administration, development, and use of new technologies, genetic considerations, and observed societal disparities. Many of these controversies and disparities persist today and will require further research to resolve.

Repeated Topical Administration of 3 nm Cerium Oxide Nanoparticles Reverts Disease Atrophic Phenotype and Arrests Neovascular Degeneration in AMD Mouse Models

Increased oxidative stress in the retina and retinal pigment epithelium is implicated in age-related macular degeneration (AMD). Antioxidant cerium oxide nanoparticles (CeO2NPs) have been used to treat degenerative retinal pathologies in animal models, although their delivery route is not ideal for chronic patient treatment. In this work, we prepared a formulation for ocular topical delivery that contains small (3 nm), nonaggregated biocompatible CeO2NPs. In vitro results indicate the biocompatible and protective character of the CeO2NPs, reducing oxidative stress in ARPE19 cells and inhibiting neovascularization related to pathological angiogenesis in both HUVEC and in in vitro models of neovascular growth. In the in vivo experiments, we observed the capacity of CeO2NPs to reach the retina after topical delivery and a subsequent reversion of the altered retinal transcriptome of the retinal degenerative mouse model DKOrd8 toward that of healthy control mice, together with signs of decreased inflammation and arrest of degeneration. Furthermore, CeO2NP eye drops' treatment reduced laser-induced choroidal neovascular lesions in mice by lowering VEGF and increasing PEDF levels. These results indicate that CeO2NP eye drops are a beneficial antioxidant and neuroprotective treatment for both dry and wet forms of AMD disease.

The Patient Voice in Neovascular Age-Related Macular Degeneration: Findings from a Qualitative Study

INTRODUCTION

Visual impairment resulting from diseases such as neovascular age-related macular degeneration (nAMD) may cause behavioural, environmental, psychological, and logistical challenges that could act as barriers to effective uptake and sustainability of treatment with anti-vascular endothelial growth factor agents (anti-VEGFs). Understanding emotions and experiences of patients with nAMD may help inform the determinants of adherence, and could contribute to improvements in ophthalmic outcomes and quality of life.

METHODS

Seventeen patients with nAMD receiving anti-VEGF injections were enrolled from three clinics: one each in France (n = 5), Germany (n = 6), and the UK (n = 6). Patients' health information and treatment characteristics were collected. Individual phone interviews were conducted by experienced health care interviewers. Transcripts were analysed thematically.

RESULTS

Patients (53% female) had a mean age of 77 years. Bilateral anti-VEGF injections were received by 24% (n = 4); and most (76%, n = 13) were adherent to their treatment. Patient emotions at diagnosis ranged from happiness at learning about the treatment for nAMD to being terrified of receiving an injection in the eye. Most patients mentioned feeling anxious and fearful before their first injection despite receiving reassurance. After the first injection, these feelings and apprehension abated for many, but not all. With the goal of maintaining the best possible vision, few (24%, n = 4) patients reported more than one missed appointment, and most had never considered stopping treatment. No patient reported additional assistance beyond family support; however, many had difficulties with recreational and domestic activities and had developed coping strategies.

CONCLUSION

This study provides insights on patients' emotions related to their experience of nAMD and its management, highlighting the varying experiences between individuals. It shows the importance of the patient's voice when considering patient care and management, and how the nature and timing of interventions can improve the experience of living with and managing nAMD.

Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications

Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.

Ranibizumab port delivery system: a clinical perspective

Age-related macular degeneration (AMD) represents a leading cause of blindness worldwide. Neovascular AMD (nAMD) is a subtype of AMD most frequently treated with intravitreal anti-vascular endothelial growth factor (aVEGF) injections, which has allowed for patients to maintain vision that would have otherwise been lost. However, the need for frequent intravitreal injections for optimal results poses a risk for undertreatment in nAMD patients due to the high treatment burden associated with current aVEGF therapy. Many novel agents and pathways are being explored and targeted for less burdensome treatment options, one of which is the ranibizumab port delivery system (PDS). The PDS is a surgically implanted, refillable device that allows for the sustained release of ranibizumab, a widely used aVEGF agent, into the vitreous cavity. Positive results non-inferior to monthly ranibizumab injections in both phase II and phase III clinical trials allowed for FDA approval of the device with refill intervals of 6 months, which represents the longest approved treatment interval to date for nAMD therapy. This article reviews the need for a durable nAMD treatment option in real-world practice, the clinical trial and extension study data for the PDS, the risk of adverse events and safety profile of the PDS and the potential clinical role of the PDS in answering the real-world needs of nAMD treatment. In addition, other pipeline sustained-treatment modalities are discussed in the context of ongoing clinical trials.

Progress and Challenges of Anti-VEGF Agents and Their Sustained-Release Strategies for Retinal Angiogenesis

Currently, the treatment for ocular neovascular diseases, including diabetic macular edema (DME) and age-related macular degeneration (AMD), mainly involves repeated intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs. Although it can preserve vision, repeated injections are an invasive treatment modality, leading to serious complications and reducing patient adherence to treatment. To reduce the frequency of administration, prolong the time of drug action, and avoid repeated intravitreal injections, the combination of sustained-release materials with anti-VEGF drug therapy has become an emphasis in ophthalmology. In this review, we highlight the current state of anti-VEGF technology, its challenges, and the sustained-release strategies under investigation or being used in clinical practice. Both continuous release and considerable therapeutic effects can be achieved by encapsulating anti-VEGF drugs in sustained-release materials to minimize the number of intravitreal injections. At present, two sustained-release materials are being tested in clinical research, and although basic research shows the strong therapeutic application prospects of extended-release drugs, its challenges mainly involve the discrepancy between the release rates in vitro and the efficiency of the drugs in vivo. Briefly, sustained release of anti-VEGF agents is an advantageous strategy for treating retinal angiogenesis.

The Efficacy and Safety of Brolucizumab for the Treatment of nAMD: A Systematic Review and Meta-Analysis

Introduction: As demonstrated in pivotal clinical trials, brolucizumab can be used to treat neovascular age-related macular degeneration (nAMD) because it antagonizes vascular endothelial growth factor (VEGF) in the vitreous. However, brolucizumab may cause retinal vasculitis obliterans in the presence of inflammation in the eyes. In the present study, a meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate the efficacy and safety of brolucizumab.

Methods:ClinicTrail.gov., Embase, Cochrane Library, and PubMed were retrieved from inception until 31 December 2021 for RCTs assessing the efficacy and safety of brolucizumab. Changes in best corrected visual acuity (BCVA) and central sub-field thickness (CSFT) and incidence of adverse events, serious adverse events, and serious ocular adverse events were extracted from eligible RCTs. A meta-analysis was performed using RevMan 5.4.1.

Results: A total of six RCTs with 3,574 participants were finally involved in this meta-analysis. The changes of best corrected visual acuity (BCVA) showed no statistically significant difference between the brolucizumab-treated group and aflibercept-treated group. Brolucizumab induced higher central sub-field thickness (CSFT) reduction than the control agent (aflibercept). The incidence of adverse events was similar between the brolucizumab group and control group (OR 0.63, 95% CI 0.37 to 1.08, p = 0.09), and brolucizumab caused fewer serious adverse events (OR 0.78, 95% CI 0.63 to 0.95, p = 0.01). However, brolucizumab could lead to more serious ocular adverse events than Lucentis and aflibercept (OR 2.15, 95% CI 1.11 to 4.16, p = 0.02).

Conclusion: Brolucizumab was non-inferior to other anti-VEGF agents in improving BCVA and decreasing CSFT. But it caused more serious ocular adverse events which is worthy of special attention by ophthalmologists.

KSI-301: an investigational anti-VEGF biopolymer conjugate for retinal diseases

INTRODUCTION

KSI-301 is an intravitreal anti-vascular endothelial growth factor (VEGF) agent in clinical trials for the treatment of neovascular age-related macular degeneration (nAMD), diabetic retinopathy, diabetic macular edema (DME), and retinal vein occlusion (RVO). Its antibody-biopolymer conjugate structure is designed to decrease clearance from the eye and increase the duration of the effect.

AREAS COVERED

This article briefly discusses the impact and mechanisms of nAMD, DME, and RVO and evaluates currently approved anti-VEGF therapies. It progresses to examine a new agent, KSI-301 and the results from numerous clinical trials in these disease areas.

EXPERT OPINION

Despite varied results in the phase 2b/3 study for nAMD, there is potential for KSI-301 to serve as a durable therapy for VEGF-mediated retinal disorders. Ongoing phase 3 trials for nAMD, DME, and RVO will provide additional evidence on its efficacy, duration, and safety profiles.

Considerations for Polymers Used in Ocular Drug Delivery

PURPOSE

Age-related eye diseases are becoming more prevalent. A notable increase has been seen in the most common causes including glaucoma, age-related macular degeneration (AMD), and cataract. Current clinical treatments vary from tissue replacement with polymers to topical eye drops and intravitreal injections. Research and development efforts have increased using polymers for sustained release to the eye to overcome treatment challenges, showing promise in improving drug release and delivery, patient experience, and treatment compliance. Polymers provide unique properties that allow for specific engineered devices to provide improved treatment options. Recent work has shown the utilization of synthetic and biopolymer derived biomaterials in various forms, with this review containing a focus on polymers Food and Drug Administration (FDA) approved for ocular use.

METHODS

This provides an overview of some prevalent synthetic polymers and biopolymers used in ocular delivery and their benefits, brief discussion of the various types and synthesis methods used, and administration techniques. Polymers approved by the FDA for different applications in the eye are listed and compared to new polymers being explored in the literature. This article summarizes research findings using polymers for ocular drug delivery from various stages: laboratory, preclinical studies, clinical trials, and currently approved. This review also focuses on some of the challenges to bringing these new innovations to the clinic, including limited selection of approved polymers.

RESULTS

Polymers help improve drug delivery by increasing solubility, controlling pharmacokinetics, and extending release. Several polymer classes including synthetic, biopolymer, and combinations were discussed along with the benefits and challenges of each class. The ways both polymer synthesis and processing techniques can influence drug release in the eye were discussed.

CONCLUSION

The use of biomaterials, specifically polymers, is a well-studied field for drug delivery, and polymers have been used as implants in the eye for over 75 years. Promising new ocular drug delivery systems are emerging using polymers an innovative option for treating ocular diseases because of their tunable properties. This review touches on important considerations and challenges of using polymers for sustained ocular drug delivery with the goal translating research to the clinic.

Metabolomics in Retinal Diseases: An Update

Retinal diseases are a leading cause of visual loss and blindness, affecting a significant proportion of the population worldwide and having a detrimental impact on quality of life, with consequent economic burden. The retina is highly metabolically active, and a number of retinal diseases are associated with metabolic dysfunction. To better understand the pathogenesis underlying such retinopathies, new technology has been developed to elucidate the mechanism behind retinal diseases. Metabolomics is a relatively new "omics" technology, which has developed subsequent to genomics, transcriptomics, and proteomics. This new technology can provide qualitative and quantitative information about low-molecular-weight metabolites (M.W. < 1500 Da) in a given biological system, which shed light on the physiological or pathological state of a cell or tissue sample at a particular time point. In this article we provide an extensive review of the application of metabolomics to retinal diseases, with focus on age-related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), glaucoma, and retinitis pigmentosa (RP).

Ten years in the making: application of CrossMab technology for the development of therapeutic bispecific antibodies and antibody fusion proteins

Bispecific antibodies have recently attracted intense interest. CrossMab technology was described in 2011 as novel approach enabling correct antibody light-chain association with their respective heavy chain in bispecific antibodies, together with methods enabling correct heavy-chain association using existing pairs of antibodies. Since the original description, CrossMab technology has evolved in the past decade into one of the most mature, versatile, and broadly applied technologies in the field, and nearly 20 bispecific antibodies based on CrossMab technology developed by Roche and others have entered clinical trials. The most advanced of these are the Ang-2/VEGF bispecific antibody faricimab, currently undergoing regulatory review, and the CD20/CD3 T cell bispecific antibody glofitamab, currently in pivotal Phase 3 trials. In this review, we introduce the principles of CrossMab technology, including its application for the generation of bi-/multispecific antibodies with different geometries and mechanisms of action, and provide an overview of CrossMab-based therapeutics in clinical trials.