A phase I study of intravitreal vascular endothelial growth factor trap-eye in patients with neovascular age-related macular degeneration

End binding-3 inhibitor activates regenerative program in age-related macular degeneration

Wet age-related macular degeneration (AMD), characterized by leaky neovessels emanating from the choroid, is a main cause of blindness. As current treatments for wet AMD require regular intravitreal injections of anti-vascular endothelial growth factor (VEGF) biologics, there is a need for the development of less invasive treatments. Here, we designed an allosteric inhibitor of end binding-3 (EB3) protein, termed EBIN, which reduces the effects of environmental stresses on endothelial cells by limiting pathological calcium signaling. Delivery of EBIN via eye drops in mouse and non-human primate (NHP) models of wet AMD prevents both neovascular leakage and choroidal neovascularization. EBIN reverses the epigenetic changes induced by environmental stresses, allowing an activation of a regenerative program within metabolic-active endothelial cells comprising choroidal neovascularization (CNV) lesions. These results suggest the therapeutic potential of EBIN in preventing the degenerative processes underlying wet AMD.

Seven-year outcomes following intensive anti-vascular endothelial growth factor therapy in patients with exudative age-related macular degeneration

BACKGROUND

Anti-vascular endothelial growth factor (VEGF) therapy is currently the most effective therapy of exudative age-related macular degeneration (AMD). The aim of this study was to assess long-term benefits of intensive aflibercept and ranibizumab anti-VEGF therapy in patients with exudative AMD.

METHODS

Two clinical trial sites recruited their original subjects for a re-evaluation 7 years after the baseline visit of the phase-3 Vascular Endothelial Growth Factor (VEGF) Trap-Eye: Investigation of Efficacy and Safety in Wet Age-Related Macular Degeneration (VIEW 2) trial. Forty-seven eyes of 47 patients with AMD originally treated with ranibizumab (14 eyes) or aflibercept (33 eyes) were included.

RESULTS

Mean number of injections was 17.8 ± 3.0 during participation in the VIEW 2 trial. Fourteen of 47 (30%) eyes were given additional injections with a mean number of 5.7 ± 4.5 after the trial. At a mean follow-up time of 82 ± 5 months best corrected visual acuity (BCVA) remained stable or improved (≤ 10 letters lost) in 55% of patients in the entire study population, in 43% in the ranibizumab group and in 60% in the aflibercept group. In both groups combined mean BCVA was 54 ± 13 letters at baseline, 65 ± 17 letters at the end of the intensive phase and 45 ± 25 letters at the end of follow-up. There was no statistically significant difference in BCVA between the two groups at baseline (p = 0.88) and at the end of follow-up (p = 0.40). Macular atrophy was observed in 96% of eyes, average area was 7.22 ± 6.31 mm² with no statistically significant difference between groups (p = 0.47). Correlation between BCVA at end-of-follow-up and the area of atrophy was significant (p < 0.001). At the end of follow-up, fluid was detected in 7 of 47 eyes (15%) indicating disease activity.

CONCLUSION

Long-term efficacy of aflibercept and ranibizumab was largely consistent. Following a two-year intensive therapy with as-needed regimen, BCVA was maintained or improved in almost half of the patients and in the ranibizumab group and more than half of the patients in the aflibercept group with very few injections. In a remarkable proportion of eyes, BCVA declined severely which underlines the need for long-term follow-ups and may indicate a more prolonged intensive therapy.

TRIAL REGISTRATIONS

VIEW 2 study: ClinicalTrials.gov ID: NCT00637377, date of registration: March 18, 2008. Long-term follow-up: IRB nr.: SE RKEB 168/2022, ClinicalTrials.gov ID: NCT05678517, date of registration: December 28, 2022, retrospectively registered.

High-Dose Aflibercept for Neovascular AMD and DME in Suboptimal Responders to Standard-Dose Aflibercept

Purpose: To assess the effect of higher dose (HD) aflibercept on visual acuity (VA), optical coherence tomography outcomes, and injection burden in eyes with neovascular age-related macular degeneration (nAMD) or diabetic macular edema (DME) that responded suboptimally to standard-dose aflibercept. Methods: This retrospective analysis included eyes with clinically significant disease activity on monthly therapy (AMT) (injection interval ≤35 days) or clinically significant increased activity on extension (IAE) (injection interval >36 days) that were switched from aflibercept 2 mg to aflibercept HD (3 mg to 4 mg). Outcomes were assessed at baseline, after injections 1 through 4, and at 6, 9, and 12 months. Results: Overall, 318 eyes of 288 adult patients were analyzed (eyes with nAMD: 59 AMT, 147 IAE; eyes with DME: 50 AMT, 62 IAE). Most of the study cohort received aflibercept HD 3 mg (nAMD: 73% AMT and 58% IAE; DME: 49% AMT and 68% IAE); the remainder received 4 mg. The mean best VA improved significantly with AMT and was maintained with IAE. In all groups, the central subfield thickness decreased significantly and the mean injection intervals increased or remained stable. No new safety signals were observed. Conclusions: Aflibercept HD might improve outcomes while decreasing treatment burden for eyes that respond suboptimally to standard dosing.

Aflibercept versus Faricimab in the Treatment of Neovascular Age-Related Macular Degeneration and Diabetic Macular Edema: A Review

Diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD) are common retinal vascular diseases responsible for most blindness in the working-age and older population in developed countries. Currently, anti-VEGF agents that block VEGF family ligands, including ranibizumab, bevacizumab (off-label use), brolucizumab, and aflibercept, are the first-line treatment for nAMD and DME. However, due to the complex pathophysiological background of nAMD and DME, non-response, resistance during anti-VEGF therapy, and relapses of the disease are still observed. Moreover, frequent injections are a psychological and economic burden for patients, leading to inadequate adhesion to therapy and a higher risk of complications. Therefore, therapeutic methods are strongly needed to develop and improve, allowing for more satisfactory disease management and lower treatment burden. Currently, the Ang/Tie-2 pathway is a promising therapeutic target for retinal vascular diseases. Faricimab is the first bispecific monoclonal antibody for intravitreal use that can neutralize VEGF and Ang-2. Due to the prolonged activity, faricimab allows extending the interval between successive injections up to three or four months in nAMD and DME patients, which can be a significant benefit for patients and an alternative to implanted drug delivery systems.

Targeting C3b/C4b and VEGF with a bispecific fusion protein optimized for neovascular age-related macular degeneration therapy

Antiangiogenesis therapies targeting vascular endothelial growth factor (VEGF) have revolutionized the treatment of neovascular ocular diseases, including neovascular age-related macular degeneration (nAMD). Compelling evidence has implicated the vital role of complement system dysregulation in AMD pathogenesis, implying it as a potential therapeutic strategy for geographic atrophy in dry AMD and to enhance the efficacy of anti-VEGF monotherapies in nAMD. This study reports the preclinical assessment and phase 1 clinical outcomes of a bispecific fusion protein, efdamrofusp alfa (code: IBI302), which is capable of neutralizing both VEGF isoforms and C3b/C4b. Efdamrofusp alfa showed superior efficacy over anti-VEGF monotherapy in a mouse laser-induced choroidal neovascularization (CNV) model after intravitreal delivery. Dual inhibition of VEGF and the complement activation was found to further inhibit macrophage infiltration and M2 macrophage polarization. Intravitreal efdamrofusp alfa demonstrated favorable safety profiles and exhibited antiangiogenetic efficacy in a nonhuman primate laser-induced CNV model. A phase 1 dose-escalating clinical trial (NCT03814291) was thus conducted on the basis of the preclinical data. Preliminary results showed that efdamrofusp alfa was well tolerated in patients with nAMD. These data suggest that efdamrofusp alfa might be effective for treating nAMD and possibly other complement-related ocular conditions.

Comparison of the effects of anti-vascular endothelial growth factor treatments on pigment epithelial detachment in age-related macular degeneration

PURPOSE

The aim of this study is to compare structural and visual outcomes of naive neovascular age-related macular degeneration patients with significant pigment epithelial detachment (PED), treated with ranibizumab and aflibercept.

METHODS

This was a retrospective case series that included 33 naive patients treated with ranibizumab and 25 with aflibercept. The patients were followed with pro re nata (PRN) after first three intravitreal injections. LogMAR visual acuity, PED height and radius on spectral domain optical coherence tomography findings were compared.

RESULTS

Baseline mean PED height was 270.39 ± 114.14 µm and 315.24 ± 115.8 µm (p = 0.14); baseline mean PED radius was 2063.64 ± 942.75 µm and 1958.88 ± 452.22 µm (p = 0.61); and baseline BCVA was 1.16 ± 0.73 and 1.09 ± 0.69 (p = 0.73), for ranibizumab, and aflibercept group, respectively. In aflibercept group, there was statistically significant decrease in PED height at first, third and 12th months. In PED radius, decrease was greater in aflibercept group, however not significant. In addition, in aflibercept group visual acuity was better at all three months; however, none of them were significant.

CONCLUSION

Although the maximum improvement was seen at third month, final visual acuity and parameters of PED were better in aflibercept group. The efficacy of the both drug to choroidal neovascularization was known; however, in cases with significant PED, aflibercept can be consider for the first-level treatment.

Negative Regulators of Angiogenesis, Ocular Vascular Homeostasis, and Pathogenesis and Treatment of Exudative AMD

Angiogenesis, the formation of new blood vessels from pre-existing capillaries, is very tightly regulated and normally does not occur except during developmental and reparative processes. This tight regulation is maintained by a balanced production of positive and negative regulators, and alterations under pathological conditions such as retinopathy of prematurity, diabetic retinopathy, and age-related macular degeneration can lead to growth of new and abnormal blood vessels. Although the role of proangiogenic factors such as vascular endothelial growth factor has been extensively studied, little is known about the roles of negative regulators of angiogenesis in the pathogenesis of these diseases. Here, we will discuss the role of thrombospondin-1 (TSP1), one of the first known endogenous inhibitors of angiogenesis, in ocular vascular homeostasis, and how its alterations may contribute to the pathogenesis of age-related macular degeneration and choroidal neovascularization. We will also discuss its potential utility as a therapeutic target for treatment of ocular diseases with a neovascular component.

Systemic safety of intravitreal anti-vascular endothelial growth factor agents in age-related macular degeneration

PURPOSE OF REVIEW

The purpose of review is to summarize the literature addressing nonocular adverse events in patients with neovascular age-related macular degeneration treated with intravitreal vascular endothelial growth factor (VEGF) inhibitors and to present possible mechanisms of effect.

RECENT FINDINGS

The incidence of overall nonocular serious adverse events varied from 0 to 39.3% and nonocular adverse events ranged from 0 to 86.9%. Few studies have reported a significant association between use of intravitreal anti-VEGF agents and overall incidence of adverse events, stroke, myocardial infarction, nonocular hemorrhage and death, with overall greater concern in patients treated with bevacizumab. Additionally, history of stroke or other arterial thromboembolic event may be a risk factor for future stroke in patients treated with intravitreal anti-VEGF agents. Theories explaining the mechanisms of increased risk of nonocular adverse events secondary to anti-VEGF agent use surround the necessity of VEGF for the normal functioning of the endothelium and the damage incurred with use of anti-VEGF agents.

SUMMARY

Current data are insufficient to definitively conclude that intravitreal anti-VEGF agents are safe, although there is a trend toward an overall favorable systemic safety profile. Caution should be exerted in patients with a history of cardiovascular disease, as these patients may be at greater risk for nonocular serious adverse events.

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.

Aflibercept: a review of its use in the treatment of choroidal neovascularization due to age-related macular degeneration

Choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) is an important cause of visual morbidity globally. Modern treatment strategies for neovascular AMD achieve regression of CNV by suppressing the activity of key growth factors that mediate angiogenesis. Vascular endothelial growth factor (VEGF) has been the major target of neovascular AMD therapy for almost two decades, and there have been several intravitreally-administered agents that have enabled anatomical restitution and improvement in visual function with continual dosing. Aflibercept (EYLEA(®)), initially named VEGF Trap-eye, is the most recent anti-VEGF agent to be granted US Food and Drug Administration approval for the treatment of neovascular AMD. Biologic advantages of aflibercept include its greater binding affinity for VEGF, a longer intravitreal half-life relative to other anti-VEGF agents, and the capacity to antagonize growth factors other than VEGF. This paper provides an up-to-date summary of the molecular mechanisms mediating CNV. The structural, pharmacodynamic, and pharmacokinetic advantages of aflibercept are also reviewed to rationalize the utility of this agent for treating CNV. Results of landmark clinical investigations, including VIEW 1 and 2 trials, and other important studies are then summarized and used to illustrate the efficacy of aflibercept for managing treatment-naïve CNV, recalcitrant CNV, and CNV due to polypoidal choroidal vasculopathy. Safety profile, patient tolerability, and quality of life measures related to aflibercept are also provided. The evidence provided in this paper suggests aflibercept to be a promising agent that can be used to reduce the treatment burden of neovascular AMD.

Comparative safety and tolerability of anti-VEGF therapy in age-related macular degeneration

Neovascular age-related macular degeneration (NVAMD) is one of the leading causes of blindness. Over the last decade, the treatment of NVAMD has been revolutionized by the development of intravitreal anti-vascular endothelial growth factor (VEGF) therapies. Several anti-VEGF medications are used for the treatment of NVAMD. The safety and tolerability of these medications deserve review given the high prevalence of NVAMD and the significant utilization of these medications. Numerous large randomized clinical trials have not shown any definitive differential safety relative to ocular or systemic safety of these medications. Intravitreal anti-VEGF therapy does appear to impact systemic VEGF levels, but the implications of these changes remain unclear. One unique safety concern relates drug compounding and the potential risks of contamination, specifically for bevacizumab. Continued surveillance for systemic safety concerns, particularly for rare events, is merited. Overall, these medications are well tolerated and effective in the treatment of NVAMD.

Subconjunctival injection of XG-102, a JNK inhibitor peptide, in patients with intraocular inflammation: a safety and tolerability study

PURPOSE

We aimed to investigate the safety, tolerability, and systemic diffusion of a single escalating dose of XG-102 (a 31-D-amino-acid peptide inhibiting JNK pathway activation), administered subconjunctivally in the treatment of post-surgery or post-trauma intraocular inflammation.

METHODS

This is a dose-escalating, tolerance Phase Ib study. Twenty patients with post-surgery or post-traumatic intraocular inflammation were assigned to 1 of the 4 dose escalating (45, 90, 450, or 900 μg XG-102) groups of 5 patients each. Patients were evaluated at 24, 48 h, 8, and 28 days following the administration of XG-102, including laboratory tests, standard eye examinations, vital signs, and occurrence of adverse events. A single plasma quantification of XG-102 was performed 30 min after administration, according to previous pharmacokinetics studies performed on volunteers.

RESULTS

A total of 17 non-serious adverse events, considered unrelated to the study treatment, were reported for 10 patients. The adverse event incidence was not related to the drug dose. All patients experienced a decrease in intraocular inflammation as of 24 h post-administration and this decrease was sustained up to 28 days thereafter. No patient required local injection or systemic administration of corticoids following the administration of XG-102. XG-102 was undetectable in the first 3 dose groups. In the fourth-dose group (900 μg) the XG-102 plasma levels were above the limit of detection for 3 patients and above the limit of quantification for 1 patient.

CONCLUSIONS

In this first clinical trial using XG-102, administered as a single subconjunctival injection as adjunct therapy, in patients with recent post-surgery or post-trauma intraocular inflammation is safe and well tolerated. Further studies are required to evaluate its efficacy.

Guidelines for the management of neovascular age-related macular degeneration by the European Society of Retina Specialists (EURETINA)

Age-related macular degeneration (AMD) is still referred to as the leading cause of severe and irreversible visual loss world-wide. The disease has a profound effect on quality of life of affected individuals and represents a major socioeconomic challenge for societies due to the exponential increase in life expectancy and environmental risks. Advances in medical research have identified vascular endothelial growth factor (VEGF) as an important pathophysiological player in neovascular AMD and intraocular inhibition of VEGF as one of the most efficient therapies in medicine. The wide introduction of anti-VEGF therapy has led to an overwhelming improvement in the prognosis of patients affected by neovascular AMD, allowing recovery and maintenance of visual function in the vast majority of patients. However, the therapeutic benefit is accompanied by significant economic investments, unresolved medicolegal debates about the use of off-label substances and overwhelming problems in large population management. The burden of disease has turned into a burden of care with a dissociation of scientific advances and real-world clinical performance. Simultaneously, ground-breaking innovations in diagnostic technologies, such as optical coherence tomography, allows unprecedented high-resolution visualisation of disease morphology and provides a promising horizon for early disease detection and efficient therapeutic follow-up. However, definite conclusions from morphologic parameters are still lacking, and valid biomarkers have yet to be identified to provide a practical base for disease management. The European Society of Retina Specialists offers expert guidance for diagnostic and therapeutic management of neovascular AMD supporting healthcare givers and doctors in providing the best state-of-the-art care to their patients.

TRIAL REGISTRATION NUMBER

NCT01318941.

Aflibercept treatment for patients with exudative age-related macular degeneration who were incomplete responders to multiple ranibizumab injections (TURF trial)

Aim

To determine the efficacy of 2.0 mg aflibercept in the management of patients with recalcitrant exudative age-related macular degeneration (AMD).

Methods

In this prospective, open-label, single-arm clinical trial, patients were seen monthly and given mandatory 2.0 mg aflibercept at baseline, months 1, 2 and 4. Pro re nata (PRN) retreatment at months 3 and 5 was performed upon evidence of disease on spectral domain-optical coherence tomography (SD-OCT). End point at month 6: mean change in Early Treatment Diabetic Retinopathy Study best corrected visual acuity (ETDRS BCVA) and central subfield thickness (CST), mean number of aflibercept injections, percentage of PRN injections required, patients with no fluid on SD-OCT and patients losing >15 letters.

Results

At baseline, 46 patients with a mean of 42 prior antivascular endothelial growth factor-A (anti-VEGF) intravitreal treatments had a mean of 74.2 letters (Snellen equivalent 20/32) and mean CST of 347 µm. ETDRS letters remained stable throughout the trial; at month 6, mean BCVA change was +0.2 letters (range −10 to +13, p=0.71). Anatomically, mean CST improved significantly from baseline at each study visit including −23.6 µm at month 1 and −27.3 µm at month 6 (p=0.018). Seventy-one of 90 (79%) possible PRN injections were required and a mean of 5.6 aflibercept injections out of the maximum six were administered. Ten of 45 (22%) patients had no retinal fluid on SD-OCT at month 6. No patient lost >15 letters.

Conclusions

Aflibercept 2.0 mg treatment maintained mean visual acuity improvements previously achieved with high-dose 2.0-mg ranibizumab injections in recalcitrant wet AMD patients. Aflibercept 2.0 mg treatment led to significant anatomic improvement and was required monthly in most patients.

Clinical Trials Registration

FDA IND#12462. NCT 01543568.

Trial Details

IND 12462, NCT 01543568 http://clinicaltrials.gov/show/NCT01543568.

Aflibercept for intravitreal injection: in neovascular age-related macular degeneration

Aflibercept is a recombinant human fusion protein that acts as a soluble decoy receptor for vascular endothelial growth factor (VEGF) family members VEGF-A, VEGF-B and placental growth factor, thereby preventing these ligands from binding to, and activating, their cognate receptors. The efficacy of intravitreal aflibercept in the treatment of wet (neovascular) age-related macular degeneration has been compared with that of intravitreal ranibizumab, the current gold standard for this indication, in two pivotal phase III studies of virtually identical design (VIEW 1 and 2). In both trials, the recommended regimen of aflibercept [2 mg every second month (after three initial monthly doses)] was shown to be noninferior to the recommended regimen of ranibizumab (0.5 mg every month) in terms of the primary endpoint of the proportion of patients who maintained their vision after 1 year of treatment; similar results were seen when monthly dosing with aflibercept (0.5 or 2 mg) was compared with ranibizumab. Over a period of 96 weeks in the VIEW studies, patients receiving the recommended regimen of aflibercept during the first year followed by modified quarterly treatment during the second year had a similar visual acuity gain to those receiving the recommended regimen of ranibizumab during first year followed by modified quarterly treatment during the second year, but on average required five fewer injections. Aflibercept was generally well tolerated in the VIEW studies; the ocular and non-ocular adverse event profile of the drug was similar to that of ranibizumab.

Aflibercept in wet AMD: specific role and optimal use

Background

Vascular endothelial growth factor (VEGF) is a naturally occurring glycoprotein in the body that acts as a growth factor for endothelial cells. It regulates angiogenesis, enhances vascular permeability, and plays a major role in wet age-related macular degeneration. The consistent association between choroidal neovascularization and increased VEGF expression provides a strong reason for exploring the therapeutic potential of anti-VEGF agents in the treatment of this disorder. Blockade of VEGF activity is currently the most effective strategy for arresting choroidal angiogenesis and reducing vascular permeability, which is frequently the main cause of visual acuity deterioration. In recent years, a number of other molecules have been developed to increase the efficacy and to prolong the durability of the anti-VEGF effect. Aflibercept (EYLEA®; Regeneron Pharmaceutical Inc and Bayer), also named VEGF Trap-eye, is the most recent member of the anti-VEGF armamentarium that was approved by the US Food and Drug Administration in November 2011. Because of its high binding affinity and long duration of action, this drug is considered to be a promising clinically proven anti-VEGF agent for the treatment of wet maculopathy.

Objective

This article reviews the current literature and clinical trial data regarding the efficacy and the pharmacological properties of VEGF-Trap eye and describes the possible advantages of its use over the currently used “older” anti-VEGF drugs.

Methods

For this review, a search of PubMed from January 1989 to May 2013 was performed using the following terms (or combination of terms): vascular endothelial growth factors, VEGF, age-related macular degeneration, VEGF-Trap eye in wet AMD, VEGF-Trap eye in diabetic retinopathy, VEGF-Trap eye in retinal vein occlusions, aflibercept. Studies were limited to those published in English.

Results and conclusion

Two Phase III clinical trials, VEGF Trap-eye Investigation of Efficacy and Safety in Wet AMD (VIEW) 1 and 2, comparing VEGF Trap-eye to ranibizumab demonstrated the noninferiority of this novel compound. The clinical equivalence of this compound against ranibizumab is maintained even when the injections are administered at 8-week intervals, which indicates the potential to reduce the risk of monthly intravitreal injections and the burden of monthly monitoring.

Antiangiogenic therapy for ischemic retinopathies

Neovascularization is a common pathological process in various retinal vascular disorders including diabetic retinopathy (DR), age-related macular degeneration (AMD) and retinal vein occlusion (RVO). The development of neovascular vessels may lead to complications such as vitreous hemorrhage, fibrovascular tissue formation, and traction retinal detachments. Ultimately, irreversible vision loss may result. Various proangiogenic factors are involved in these complex processes. Different antiangiogenic drugs have been formulated in an attempt treat these vascular disorders. One factor that plays a major role in the development of retinal neovascularization is vascular endothelial growth factor (VEGF). Anti-VEGF agents are currently FDA approved for the treatment of AMD and RVO. They are also extensively used as an off-label treatment for diabetic macular edema (DME), proliferative DR, and neovascular glaucoma. However, at this time, the long-term safety of chronic VEGF inhibition has not been extensively evaluated. A large and rapidly expanding body of research on angiogenesis is being conducted at multiple centers across the globe to determine the exact contributions and interactions among a variety of angiogenic factors in an effort to determine the therapeutic potential of antiangiogenic agent in the treatment of a variety of retinal diseases.

Aflibercept for the treatment of age-related macular degeneration

Aflibercept is a novel, recombinant, fusion protein that consists of portions of vascular endothelial growth factor (VEGF) receptor (R) 1 and VEGFR2 extracellular domains fused to the Fc portion of human immunoglobulin G1. It exhibits higher affinity for VEGF-A/-B and binds all the VEGF isoforms (VEGF-B and -C, placental growth factor). The efficacy of aflibercept was assessed in two randomized, double-masked, multicenter, active-controlled, clinical trials in patients with choroidal neovascularization due to exudative age-related macular degeneration (AMD) and compared it’s efficacy to ranibizumab, which is already Food and Drug Administration (FDA)-approved for patients with wet AMD. In the two trials known as VIEW 1 and VIEW 2, aflibercept was as effective when dosed as 2 mg every 8 weeks after 3 monthly loading doses compared to monthly ranibizumab. Aflibercept was well tolerated with very rare systemic adverse events, including arterial thromboembolic events (ATEs). The incidence of ATEs was 1.8% during the first year of the clinical trials and included non-fatal strokes, non-fatal myocardial infarction, or death from vascular events or an unknown cause. In November 2011, aflibercept received FDA approval and is currently used in clinical practice for patients with wet AMD.

A Dedicated Low-Cost Fluorescence Microfluidic Device Reader for Point-of-Care Ocular Diagnostics

Microfluidic fluorescence assay devices show great promise as preclinical and clinical diagnostic instruments. Normally, fluorescence signals from microfluidic chips are quantified by analysis of images obtained with a commercial fluorescence microscope. This method is unnecessarily expensive, time consuming, and requires significant operator training, particularly when considering future clinical translation of the technology. In this work, we developed a dedicated low cost fluorescence microfluidic device reader (FMDR) to read sandwich immunofluorescence assay (sIFA) devices configured to detect vascular endothelial growth factor ligand concentrations in ocular fluid samples. Using a series of sIFA calibration standards and a limited set of human ocular fluid samples, we demonstrated that our FMDR reader has similar sensitivity and accuracy to a fluorescence microscope for this task, with significantly lower total cost and reduced reading time. We anticipate that the reader could be used with minor modifications for virtually any fluorescence microfluidic device.

Aflibercept: newly approved for the treatment of macular edema following central retinal vein occlusion

OBJECTIVE

To review the pharmacology, efficacy, and safety data available for aflibercept and compare the drug to other therapeutic options for treatment of macular edema following central retinal vein occlusion (CRVO) to determine its likely role in therapy.

DATA SOURCES

A PubMed search using the terms aflibercept and VEGF trap-eye was conducted to identify initial literature sources. No timeframe was used for exclusion of older trials. All trials referenced were published between January 1995 and December 2012.

STUDY SELECTION AND DATA EXTRACTION

Trials pertaining to oncologic use were excluded, as were studies conducted in animals and those written in a language other than English. Abstracts of the remaining trials were evaluated for determination of relevance to this review. Additional information sources were obtained via Internet and PubMed following a review of references.

DATA SYNTHESIS

While previous Phase 1, 2, and 3 trials for other indications (age-related macular degeneration and diabetic macular edema) have shown intravitreal injections of aflibercept to be safe and well tolerated in many patients, preliminary results from the ongoing COPERNICUS and GALILEO trials proved the efficacy of this medication in treating macular edema secondary to CRVO. Of the combined 358 patients studied in COPERNICUS and GALILEO, 56% and 60%, respectively, of the patients receiving aflibercept 2 mg monthly achieved at least a 15-letter improvement in best-corrected visual acuity (BCVA) from baseline over 6 months compared with just 12% and 22% in the control group (p < 0.01 for both). Additionally, in COPERNICUS and GALILEO, patients achieved a 21.3- and 14.7-letter improvement, respectively, in BCVA compared with placebo (p < 0.01 for both).

CONCLUSIONS

In September 2012, aflibercept became the second vascular endothelial growth factor (VEGF) inhibitor approved for treatment of macular edema secondary to CRVO. While efficacy and safety appear similar to other anti-VEGF treatments, the higher potency, binding affinity, and duration of action make aflibercept an appealing new option.

Preferred therapies for neovascular age-related macular degeneration

PURPOSE OF REVIEW

This report reviews the current treatment strategies and the most recent clinical trials in the treatment of neovascular age-related macular degeneration.

RECENT FINDINGS

The functional and anatomic outcomes achieved in the pivotal ranibizumab trials with monthly injections set the standard for comparison. Since then, various modified dosing regimens with the aim of lessening the treatment burden associated with monthly injections have been investigated. Additionally, level I evidence now exists for the noninferiority of bevacizumab, as compared to ranibizumab, in the treatment of neovascular age-related macular degeneration (AMD) through 1 year of follow-up. Aflibercept has emerged as a new anti- vascular endothelial growth factor (VEGF) therapy showing encouraging treatment results at 1 year. Novel treatments combined with anti-VEGF agents such as localized radiation are currently being investigated.

SUMMARY

Anti-VEGF monotherapy remains the preferred therapy for the management of neovascular AMD at the present time. Aflibercept is a new, FDA-approved, effective, anti-VEGF agent available for clinical use. Ongoing clinical trials will help determine the optimal dosing regimens for all of these agents, as well as the long-term efficacy and safety of combination therapy modalities.

Review of Aflibercept for the Treatment of Neovascular Age-Related Macular Degeneration

The treatment of exudative age-related macular degeneration (AMD) has been completely transformed by the development of drugs that bind vascular endothelial growth factor (VEGF). The antibody-based VEGF inhibitors bevacizumab and ranibizumab usually prevent the enlargement of choroidal neovascular membranes, reduce vascular permeability, and improve visual acuity. The newest VEGF inhibitor, aflibercept, is a soluble fusion protein that binds all isoforms of VEGF-A, VEGF-B, and placental growth factor with high affinity. Preclinical studies demonstrated aflibercept's ability to prevent experimental neovascularization and tumor growth in animal models. In phase 3 trials for exudative AMD, patients who received aflibercept avoided moderate vision loss and experienced improved visual acuity comparable to those who received ranibizumab. Additionally, patients who were treated with aflibercept 2 mg every 8 weeks (after 3 monthly loading doses) had similar visual results to those treated every 4 weeks. When treated as needed during the second year of the trials, patients were able to last an average of 3 months between aflibercept injections. Since its regulatory approval, aflibercept has also been found to perform well as a salvage therapy for eyes that respond incompletely to ranibizumab and bevacizumab. Because aflibercept can be administered less frequently than ranibizumab, it promises to decrease the frequency of patients’ visits to physicians’ offices in addition to the overall cost of AMD therapy.

Aflibercept in wet age-related macular degeneration: a perspective review

In the treatment of neovascular age-related macular degeneration (AMD), vascular endothelial growth factor (VEGF) has emerged as a key target of therapy. Currently, patients with neovascular AMD are treated with monthly intravitreal injections of anti-VEGF medications. Aflibercept is a novel recombinant fusion protein engineered to bind all isoforms of VEGF-A, VEGF-B, and placental growth factor. It is the latest medication to receive US Federal Drug Administration (FDA) approval for the treatment of neovascular AMD. Theoretical models suggest this molecule may have a longer duration of action compared with current treatments. The results of the VEGF Trap-Eye: Investigation of Efficacy and Safety in wet Age-related Macular Degeneration studies (VIEW 1 and VIEW 2) support this by demonstrating that aflibercept, dosed every 2 months after a monthly loading dose for 3 months, was noninferior in the proportion of patients who maintained or improved vision at 52 weeks compared with monthly injections of ranibizumab. These results were maintained over the 2 years of the studies. Aflibercept (Eylea; Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA and Bayer, Basel, Switzerland) was approved by the FDA for the treatment of neovascular AMD on 18 November 2011.

Retinopathy in diabetes

With the incidence, and prevalence of diabetes mellitus increasing worldwide, diabetic retinopathy is expected to reach epidemic proportions. The aim of this chapter is to introduce diabetic retinopathy, a leading cause of blindness in people of the working age. The clinical course of retinopathy, anatomical changes, its pathogenesis and current treatment are described, followed by an overview of the emerging drug therapies for the potential treatment of this sight-threatening complication of diabetes.

Age-related macular degeneration: current treatment and future options

Age-related macular degeneration is the leading cause of visual impairment among older adults in the developed world. Epidemiological studies have revealed a number of genetic, ocular and environmental risk factors for this condition, which can be addressed by disease reduction strategies. We discuss the various treatment options for dry and exudative age-related macular degeneration available and explain how the recommended treatment depends on the exact type, location and extent of the degeneration. Currently, vascular endothelial growth factor (VEGF) inhibition therapy is the best available treatment for exudative age-related macular degeneration but is limited by the need for repeated intravitreal injections. The current treatment regime is being refined through research on optimal treatment frequency and duration and type of anti-VEGF drug. Different modes of drug delivery are being developed and in the future other methods of VEGF inhibition may be used.

The VEGF pathway in cancer and disease: responses, resistance, and the path forward

Antiangiogenesis was proposed as a novel target for the treatment of cancer 40 years ago. Since the original hypothesis put forward by Judah Folkman in 1971, factors that mediate angiogenesis, their cellular targets, many of the pathways they signal, and inhibitors of the cytokines and receptors have been identified. Vascular endothelial growth factor (VEGF) is the most prominent among the angiogenic cytokines and is believed to play a central role in the process of neovascularization, both in cancer as well as other inflammatory diseases. This article reviews the biology of VEGF and its receptors, the use of anti-VEGF approaches in clinical disease, the toxicity of these therapies, and the resistance mechanisms that have limited the activity of these agents when used as monotherapy.

Corneal neovascularization: an anti-VEGF therapy review

Corneal neovascularization is a serious condition that can lead to a profound decline in vision. The abnormal vessels block light, cause corneal scarring, compromise visual acuity, and may lead to inflammation and edema. Corneal neovascularization occurs when the balance between angiogenic and antiangiogenic factors is tipped toward angiogenic molecules. Vascular endothelial growth factor (VEGF), one of the most important mediators of angiogenesis, is upregulated during neovascularization. In fact, anti-VEGF agents have efficacy in the treatment of neovascular age-related macular degeneration, diabetic retinopathy, macular edema, neovascular glaucoma, and other neovascular diseases. These same agents have great potential for the treatment of corneal neovascularization. We review some of the most promising anti-VEGF therapies, including bevacizumab, VEGF trap, siRNA, and tyrosine kinase inhibitors.

The past, present, and future of exudative age-related macular degeneration treatment

Treatment of exudative age-related macular degeneration has been revolutionized within the last 6 years with the introduction of vascular endothelial growth factor neutralizing agents. Previously popular “destructive treatments,” such as laser photocoagulation and photodynamic treatment have either been abandoned or used as an adjunct to pharmacotherapy. Despite the increase in vision after antivascular endothelial growth factor (VEGF) agents, they require repetitive and costly intravitreal injections that also carry the inherit risks of infection, retinal tears, and detachment. Several new and more potent VEGF inhibitors are at different stages of development. The goal of evolving pharmacotherapy is to preserve the therapeutic effect while reducing or eliminating the discomfort of intravitreal drug delivery, as well as identify new therapeutic targets. Complement inhibitors, immunomodulators, integrin inhibitors are a few of the new class of drugs that are expected to be in our armamentarium soon. Current medications act to decrease leakage through abnormal subretinal choroidal vasculature and promote involution. However, these medications are only effective in treating the active stage of the choroidal neovascular membrane. Restoration of vision of a large number of patients with involuted choroidal neovascular membranes is warranted. For this purpose, tissue engineering techniques have been employed to reconstruct the subretinal anatomy. Discovery of biomarkers, pharmacogenetics, and very specific targeting holds the promise of increased potency and safety in the future.

Highly potent VEGF-A-antagonistic DARPins as anti-angiogenic agents for topical and intravitreal applications

The next-generation ophthalmic anti-VEGF therapeutics must aim at being superior to the currently available agents with regard to potency and improved drug delivery, while still being stable and safe to use at elevated concentrations. We show here the generation of a set of highly potent VEGF-A antagonistic DARPins (designed ankyrin repeat proteins) delivering these properties. DARPins with single-digit picomolar affinity to human VEGF-A were generated using ribosome display selections. Specific and potent human VEGF-A binding was confirmed by ELISA and endothelial cell sprouting assays. Cross-reactivity with VEGF-A of several species was confirmed by ELISA. Intravitreally injected DARPin penetrated into the retina and reduced fluorescein extravasation in a rabbit model of vascular leakage. In addition, topical DARPin application was found to diminish corneal neovascularization in a rabbit suture model, and to suppress laser-induced neovascularization in a rat model. Even at elevated doses, DARPins were safe to use. The fact that several DARPins are highly active in various assays illustrates the favorable class behavior of the selected binders. Anti-VEGF-A DARPins thus represent a novel class of highly potent and specific drug candidates for the treatment of neovascular eye diseases in both the posterior and the anterior eye chamber.

Aflibercept for age-related macular degeneration: a game-changer or quiet addition?

PURPOSE

To describe the pharmacokinetics, preclinical studies, and clinical trials of the newly approved anti-vascular endothelial growth factor (VEGF) drug aflibercept (Eylea (VEGF Trap-Eye); Regeneron; and Bayer).

DESIGN

Review with editorial commentary.

METHODS

A review of the medical literature and pertinent Internet postings combined with analysis of key studies with expert opinion regarding the use of aflibercept for the treatment of exudative age-related macular degeneration.

RESULTS

Aflibercept, a fusion protein with binding domains from native VEGF receptors, binds VEGF-A, VEGF-B, and placental growth factors 1 and 2 with high affinity. Preclinical ophthalmologic studies demonstrated that aflibercept suppresses choroidal neovascularization in several animal models. The results of phase 1 and 2 trials showed excellent short-term suppression of choroidal neovascularization in patients with exudative age-related macular degeneration and suggested a longer durability of aflibercept compared with other anti-VEGF drugs. The pivotal phase 3 Vascular Endothelial Growth Factor (VEGF) Trap-Eye: Investigation of Efficacy and Safety in Wet Age-Related Macular Degeneration 1 and 2 trials showed that monthly and bimonthly aflibercept were noninferior to monthly ranibizumab at preventing vision loss (< 15-letter loss) with comparable vision gains and safety. Year 2 treatment involved monthly pro re nata injections with required injections every 3 months and maintained vision gains from the first year, with an average of 4.2 injections of aflibercept and 4.7 injections of ranibizumab.

CONCLUSIONS

Aflibercept promises to deliver excellent visual outcomes for exudative age-related macular degeneration patients while undergoing fewer injections compared with ranibizumab. With a wholesale cost of $1850 per dose, the cost per patient with aflibercept treatment promises to be lower than with ranibizumab.

Clinical and differential utility of VEGF inhibitors in wet age-related macular degeneration: focus on aflibercept

Age-related macular degeneration (AMD) has become a major public health problem and a leading cause of blindness in industrialized nations. AMD results from the ageing eye's inability to metabolize and dispose completely of photoreceptor outer segments and other waste products. As a result, lipids, particularly apolipoproteins, accumulate within Bruch's membrane, leading to chronic ischemia and inflammation. The subsequent upregulation of inflammatory cytokines and growth factors, including vascular endothelial growth factor (VEGF), induces the growth of neovascular membranes from the choriocapillaris into the subretinal or subretinal pigment epithelium spaces. To counter this, intravitreally administered drugs (pegaptanib, bevacizumab, ranibizumab) that specifically target VEGF have become the standard treatment for exudative AMD. Aflibercept, a recently approved fusion protein, binds to all isoforms of both VEGF-A and placental growth factor with high affinity. Phase III trials showed that monthly or every other month injections of aflibercept prevent vision loss (fewer than 15 letters) in 95% of patients. Additionally, aflibercept injections every 4 or 8 weeks produce average vision gains of 6.9 letters to 10.9 letters, comparable with those achieved with monthly ranibizumab. After one year of regularly administered aflibercept injections, patients required an average of only 4.2 injections during the second year. Aflibercept promises to decrease the injection frequency required for many patients and appears to serve as an effective "salvage" therapy for patients who respond poorly to other anti-VEGF drugs.

Effects of intravitreal injection of KH902, a vascular endothelial growth factor receptor decoy, on the retinas of streptozotocin-induced diabetic rats

AIMS

KH902 is a fusion protein that can bind vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) through its binding ligand taken from the domains of VEGF receptor 1 and VEGF receptor 2 (VEGFR2). This study was to investigate the effects of intravitreal injection of KH902 on the retinas of streptozotocin-induced diabetic rats.

METHODS

Two weeks after induction of diabetes, the left eyes of diabetic rats in each group received an intravitreal injection of phosphate-buffered saline (PBS), Avastin or KH902 solution, respectively. Four weeks after intravitreal injection, retinal electrophysiological function and the integrity of inner blood retinal barrier (iBRB) were measured by electroretinogram and Evans blue perfusion. The protein levels of VEGF signal pathway were assayed by western blot. The expression and distribution of claudin-5 and occludin were analysed by double immunofluorescent staining under confocal microscope. The expression of VEGFR2 and PlGF was measured by immunohistochemistry.

RESULTS

Four weeks after intravitreal injection, KH902-treated rats had better retinal electrophysiological function, less retinal vessel leakage and lower levels of VEGFR2, PI3K, AKT, p-AKT, p-ERK and p-SRC than PBS or Avastin-treated rats. The distribution of claudin-5 and occludin in the retinal vessels of diabetic rats treated by KH902 was smoother and more uniform than those of diabetic rats treated by PBS or Avastin. The expression of PlGF and VEGFR2 in KH902-treated rats was decreased compared with those in PBS or Avastin-treated rats.

CONCLUSIONS

KH902 could improve retinal electrophysiological function and inhibit the breakdown of iBRB by inhibiting the expression of VEGFR2, PlGF and PI3K, and the activation of SRC, AKT and ERK.

Aflibercept: a Potent Vascular Endothelial Growth Factor Antagonist for Neovascular Age-Related Macular Degeneration and Other Retinal Vascular Diseases

Introduction

In the western hemisphere, age-related macular degeneration (AMD) is the leading cause of visual loss in the elderly. Currently approved therapies for AMD include argon laser, photodynamic therapy, and antivascular endothelial growth factor (VEGF) therapy. The index review discusses aflibercept (VEGF Trap-Eye) in the context of current anti-VEGF therapies for neovascular AMD and other retinal vascular diseases. It highlights important differences between VEGF Trap-Eye and currently used anti-VEGF therapies for neovascular AMD; and discusses the efficacy of these treatments utilizing information from landmark clinical trials.

Methods

A systematic search of literature was conducted on PubMed, Science Direct, and Scopus with no limitations of language or years of publication.

Results

Preclinical studies have shown that VEGF Trap-Eye binds to VEGF-A with a higher affinity than other anti-VEGF molecules; and that it also binds to placental growth factor (PlGF). In clinical trials, VEGF Trap-Eye has been shown to be as effective in the treatment of neovascular AMD as other anti-VEGF therapies and possibly to have a longer duration of drug activity.

Conclusion

VEGF Trap-Eye has enhanced the treatment options currently available for the management of neovascular AMD. The comparable efficacy of VEGF Trap-Eye (to other anti-VEGF agents) coupled with its longer dosing interval may decrease the number of annual office visits for patients with AMD and their caregivers.

Canadian expert consensus: optimal treatment of neovascular age-related macular degeneration

BACKGROUND

New therapeutic approaches, particularly anti-vascular endothelial growth factor (anti-VEGF) therapies, prevent, and in some cases reverse, vision damage caused by age-related macular degeneration (AMD). Unequal access to care across Canada remains a problem for many retina specialists and their patients.

OBJECTIVE

To develop a consensus concerning the management of patients with exudative age-related macular degeneration (AMD).

DESIGN

Consensus document.

PARTICIPANTS

Ten Canadian retina specialists.

METHODS

The development of a consensus among Canadian experts concerning optimal treatment of AMD began with a review of the clinical evidence, daily practices, existing guidelines, and current national and international approvals and policies. The experts met on June 29, 2010, in Quebec City to discuss their findings and to propose strategies for consensus.

RESULTS

The result of this expert panel is a consensus proposal for Canadian ophthalmologists and retina specialists who are treating patients with or at risk for developing neovascular AMD.

CONCLUSIONS

The consensus provides guidelines to aid retina specialists in managing exudative AMD. Currently, ranibizumab is the only agent with sufficient Level I evidence and a Health Canada-approved indication for the treatment of wet AMD. Bevacizumab has been shown to be noninferior in preserving and improving visual acuity when compared to ranibizumab. Potential safety differences between the 2 drugs remain to be elucidated. The positioning of ranibizumab in this therapeutic area will be further defined as additional data for existing and emerging therapies become available. Until then, this agent remains the therapy of choice for individuals with neovascular AMD.