Anti-vascular endothelial growth factor for neovascular age-related macular degeneration: a meta-analysis of randomized controlled trials

Evidence-Based Use of Bevacizumab in the Management of Neovascular Age-Related Macular Degeneration

Indicated for colorectal cancer for decades, bevacizumab has been widely used off label to treat retinal diseases, and the benefits of its use, specifically in neovascular age-related macular degeneration, have been demonstrated in multiple clinical trials. The intravitreal delivery of bevacizumab requires it to be aseptically repackaged into individual syringes by compounding pharmacies for use in the eye. Although the repackaging process is permitted by the US Food and Drug Administration, the resultant product does not meet the specific standards of products approved for use as ophthalmic injectables nor is the parenteral innovator solution compliant with ophthalmic standards. Studies have also demonstrated variability in the quality and quantity of repackaged bevacizumab. This narrative review summarizes the evidence and discusses the role of off-label bevacizumab in the treatment and management of retinal diseases, its mechanism of action, current challenges and provides a critical appraisal of current evidence, clinical implications, and future directions. [Ophthalmic Surg Lasers Imaging Retina 2024;55:155-162.].

Patient-Centered Economic Burden of Exudative Age-Related Macular Degeneration: Retrospective Cohort Study

BACKGROUND

Exudative age-related macular degeneration (AMD), one of the leading causes of blindness, requires expensive drugs such as anti-vascular endothelial growth factor (VEGF) agents. The long-term regular use of effective but expensive drugs causes an economic burden for patients with exudative AMD. However, there are no studies on the long-term patient-centered economic burden of exudative AMD after reimbursement of anti-VEGFs.

OBJECTIVE

This study aimed to evaluate the patient-centered economic burden of exudative AMD for 2 years, including nonreimbursement and out-of-pocket costs, compared with nonexudative AMD using the Observational Medical Outcomes Partnership (OMOP) Common Data Model (CDM).

METHODS

This retrospective cohort study was conducted using the OMOP CDM, which included 2,006,478 patients who visited Seoul National University Bundang Hospital from June 2003 to July 2019. We defined the exudative AMD group as patients aged >50 years with a diagnosis of exudative AMD and a prescription for anti-VEGFs or verteporfin. The control group was defined as patients aged >50 years without a diagnosis of exudative AMD or a prescription for anti-VEGFs or verteporfin. To adjust for selection bias, controls were matched by propensity scores using regularized logistic regression with a Laplace prior. We measured any medical cost occurring in the hospital as the economic burden of exudative AMD during a 2-year follow-up period using 4 categories: total medical cost, reimbursement cost, nonreimbursement cost, and out-of-pocket cost. To estimate the average cost by adjusting the confounding variable and overcoming the positive skewness of costs, we used an exponential conditional model with a generalized linear model.

RESULTS

We identified 931 patients with exudative AMD and matched 783 (84.1%) with 2918 patients with nonexudative AMD. In the exponential conditional model, the total medical, reimbursement, nonreimbursement, and out-of-pocket incremental costs were estimated at US $3426, US $3130, US $366, and US $561, respectively, in the first year and US $1829, US $1461, US $373, and US $507, respectively, in the second year. All incremental costs in the exudative AMD group were 1.89 to 4.25 and 3.50 to 5.09 times higher in the first and second year, respectively, than those in the control group (P<.001 in all cases).

CONCLUSIONS

Exudative AMD had a significantly greater economic impact (P<.001) for 2 years on reimbursement, nonreimbursement, and out-of-pocket costs than nonexudative AMD after adjusting for baseline demographic and clinical characteristics using the OMOP CDM. Although economic policies could relieve the economic burden of patients with exudative AMD over time, the out-of-pocket cost of exudative AMD was still higher than that of nonexudative AMD for 2 years. Our findings support the need for expanding reimbursement strategies for patients with exudative AMD given the significant economic burden faced by patients with incurable and fatal diseases both in South Korea and worldwide.

Optimizing Visual Outcomes in Patients With Neovascular Age-Related Macular Degeneration: the Potential Value of Sustained Anti-VEGF Therapy

Neovascular age-related macular degeneration (nAMD) leads to irreversible central vision loss if untreated. Frequent administration of anti-vascular endothelial growth factor (anti-VEGF) injections inhibits disease activity with excellent functional and morphological benefits. However, these injections pose a heavy therapeutic burden, and treatment discontinuation is common. Although current anti-VEGF treatment paradigms, such as treat-and-extend, mitigate treatment burden while still leading to acceptable vision outcomes, they fail to sustain initial vision gains for many. Novel longer-acting anti-VEGF therapies may reduce the overall burden on nAMD patients. Gene therapy might offer a paradigm shift by providing continuous expression of anti-VEGF, potentially decreasing treatment requirements and improving long-term vision outcomes. [Ophthalmic Surg Lasers Imaging Retina 2023;54:654-659.].

Discovery of Aptamers and the Acceleration of the Development of Targeting Research in Ophthalmology

Aptamers are widely applied to diagnosis and therapy because of their targeting. However, the current progress of research into aptamers for the treatment of eye disorders has not been well-documented. The current literature on aptamers was reviewed in this study. Aptamer-related drugs and biochemical sensors have been evaluated for several eye disorders within the past decade; S58 targeting TGF-β receptor II and pegaptanib targeting vascular endothelial growth factor (VEGF) are used to prevent fibrosis after glaucoma filtration surgery. Anti-brain-derived neurotrophic factor aptamer has been used to diagnose glaucoma. The first approved aptamer drug (pegaptanib) has been used to inhibit angiogenesis in age-related macular degeneration (AMD) and diabetic retinopathy (DR), and its efficacy and safety have been demonstrated in clinical trials. Aptamers, including E10030, RBM-007, AS1411, and avacincaptad pegol, targeting other angiogenesis-related biomarkers have also been discovered and subjected to clinical trials. Aptamers, such as C promoter binding factor 1, CD44, and advanced end products in AMD and DR, targeting other signal pathway proteins have also been discovered for therapy, and biochemical sensors for early diagnosis have been developed based on aptamers targeting VEGF, connective tissue growth factor, and lipocalin 1. Aptamers used for early detection and treatment of ocular tumors were derived from other disease biomarkers, such as CD71, nucleolin, and high mobility group A. In this review, the development and application of aptamers in eye disorders in recent years are systematically discussed, which may inspire a new link between aptamers and eye disorders. The aptamer development trajectory also facilitates the discovery of the pathogenesis and therapeutic strategies for various eye disorders.

More than meets the eye: The role of microglia in healthy and diseased retina

Microglia are the main resident immune cells of the nervous system and as such they are involved in multiple roles ranging from tissue homeostasis to response to insults and circuit refinement. While most knowledge about microglia comes from brain studies, some mechanisms have been confirmed for microglia cells in the retina, the light-sensing compartment of the eye responsible for initial processing of visual information. However, several key pieces of this puzzle are still unaccounted for, as the characterization of retinal microglia has long been hindered by the reduced population size within the retina as well as the previous lack of technologies enabling single-cell analyses. Accumulating evidence indicates that the same cell type may harbor a high degree of transcriptional, morphological and functional differences depending on its location within the central nervous system. Thus, studying the roles and signatures adopted specifically by microglia in the retina has become increasingly important. Here, we review the current understanding of retinal microglia cells in physiology and in disease, with particular emphasis on newly discovered mechanisms and future research directions.

Impact of intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell and nerve fibre layer thickness in Neovascular age‐related macular degeneration

PURPOSE

To compare the effects of monotherapy with intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell layer (RGCL) and retinal nerve fibre layer (RNFL) in patients with naïve neovascular age-related macular degeneration (nAMD).

METHODS

This is a retrospective cohort study with three-groups comparison. 83 patients and 97 eyes on continuous monotherapy with an intravitreal anti-vascular endothelial growth factor (anti-VEGF) were followed for 24 months and divided into three groups according to anti-VEGF (aflibercept: 25 eyes, ranibizumab: 34 eyes, bevacizumab: 38 eyes). Main outcome measures included: RGCL and RNFL thickness, best corrected visual acuity (BCVA), central macular thickness (CMT), macular volume (MV) and the presence of intraretinal fluids (IRF), subretinal fluids (SRF) and retinal pigment epithelial atrophy (RPE-atrophy). All outcome measures were recorded at the time of the first injection, 1 and 2 years after treatment and compared longitudinally and between groups.

RESULTS

The mean age was 79 ± 7 years. The RGCL thickness, MV, CMT and the presence of IRF and SRF decreased significantly within all three medication groups (p < 0.05 for all) with no significant difference between groups over the 2-year follow-up period (p > 0.10 for all). The decrease in RNFL thickness was not significant within or between the groups after a 2-year follow-up (p > 0.055 for all). RPE-atrophy increased significantly after 2 years in all three groups (p < 0.028 for all) with no significant difference between groups at all three time points (p > 0.307 for all). BCVA was comparable between the three groups over the 2-year follow-up period (p > 0.22 for all).

CONCLUSIONS

Monotherapy with intravitreal aflibercept, bevacizumab and ranibizumab was associated with comparable significant decreases in RGCL thickness, CMT, MV, IRF and SRF in naïve nAMD patients during the first 2 years of treatment. Furthermore, no significant differences either in BCVA or RNFL thickness were observed between the three intravitreal anti-VEFGs during the first 2 years of treatment.

RISK OF INTRAOCULAR INFLAMMATION AFTER INJECTION OF ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR AGENTS: A Meta-analysis

PURPOSE

This meta-analysis investigates the incidence of intraocular inflammation (IOI) after intravitreal antivascular endothelial growth factor injections in neovascular age-related macular degeneration.

METHODS

A systematic search was performed on Ovid MEDLINE, Embase, and Cochrane Central from January 2005 to April 2021. Randomized controlled trials comparing IOI after intravitreal bevacizumab, ranibizumab, brolucizumab, or aflibercept in neovascular age-related macular degeneration were included. Primary outcomes were sight-threatening IOI, final best-corrected visual acuity, and change in best-corrected visual acuity from baseline. Secondary outcomes included the incidence of other IOI events. Meta-analysis was performed using a random-effects model.

RESULTS

Overall, 11,460 unique studies were screened, of which 14 randomized controlled trials and 6,759 eyes at baseline were included. There was no difference between agents for the risk of endophthalmitis and retinal vascular occlusion. Compared with aflibercept, brolucizumab had a higher incidence of generalized IOI (risk ratio = 6.24, 95% confidence interval = [1.40-27.90]) and vitreous haze/floaters (risk ratio = 1.64, 95% confidence interval = [1.00-2.67]). There were no significant differences between comparators for other secondary end points.

CONCLUSION

There was no difference in the risk of severe sight-threatening IOI outcomes between intravitreal antivascular endothelial growth factor agents. There was a significantly higher risk of generalized IOI after brolucizumab relative to aflibercept. Our results alongside other recent safety findings suggest the need for further investigation in the risk-benefit profile of brolucizumab for the treatment of neovascular age-related macular degeneration.

Age differential response to bevacizumab therapy in choroidal neovascularization in rabbits

Choroidal neovascularization (CNV) in young rabbits has been shown to have a rapid, robust response after treatment with bevacizumab, an anti-vascular endothelial growth factor (VEGF) medication. This investigation evaluates an age differential response to bevacizumab in older populations of rabbits using multimodal high resolution molecular imaging. Young (4 months old) and life span (14 months old) rabbits were given subretinal injections of Matrigel and VEGF to produce CNV. All CNV rabbit models were then treated with a bevacizumab intravitreal injection. Rabbits were then monitored longitudinally using photoacoustic microscopy (PAM), optical coherence tomography (OCT), color photography, and fluorescence imaging. Chain-like gold nanoparticle clusters (CGNP) conjugated with tripeptide arginylglycylaspartic acid (RGD) was injected intravenously for molecular imaging. Robust CNV developed in both young and old rabbits. After intravitreal bevacizumab injection, fluorescence signals were markedly decreased 90.13% in the young group. In contrast, old rabbit CNV area decreased by only 10.56% post-bevacizumab treatment. OCT images confirmed a rapid decrease of CNV in the young group. CGNPs demonstrated high PAM signal in old rabbits and minimal PAM signal in young rabbits after bevacizumab, indicating CNV regression. There is a significant difference in response to intravitreal bevacizumab treatment between young and old rabbits with CNV which can be monitored with multimodal molecular imaging. Old rabbits demonstrate significant persistent disease activity. This represents the first large eye model of persistent disease activity of CNV and could serve as the foundation for future investigations into the mechanism of persistent disease activity and the development of novel therapies.

Efficacy and Safety of Antivascular Endothelial Growth Factor (Anti-VEGF) in Treating Neovascular Age-Related Macular Degeneration (AMD): A Systematic Review and Meta-analysis

This study is aimed at assessing the efficacy and safety of antivascular endothelial growth factor (anti-VEGF) inhibitors in treating age-related macular degeneration (AMD). PubMed, Embase, and Cochrane library were searched. Weighted mean difference (WMD) and relative risk (RR) with 95% confidence interval (CI) were applied to assess outcomes. Eighteen randomized controlled trials involved 8,847 neovascular AMD patients were selected for the meta-analysis. Pegaptanib (WMD: 6.70; $P<0.001$ ) and ranibizumab (WMD: 17.80; $P<0.001$ ) were associated with greater BCVA changes than control after 1 year. Bevacizumab was linked with less changes in central macular thickness after 1 year compared to control (WMD: -38.50; $P<0.001$ ), but more changes compared to ranibizumab (WMD: 10.69; $P=0.024$ ). The incidence of gain of 15 or more letter visual acuity after 1 year was increased when compared with bevacizumab versus control (RR: 7.80; $P=0.001$ ), pegaptanib versus control (RR: 2.83; $P=0.015$ ), and ranibizumab versus control (RR: 3.92; $P=0.003$ ). Moreover, ranibizumab was associated with more BCVA changes and an increased incidence of gain of 15 or more letter visual acuity after 2 years compared with control (RR: 5.77; $P<0.001$ ). This study found that most anti-VEGF inhibitors provided better efficacy than non-anti-VEGF intervention, and the treatment effectiveness among various anti-VEGF agents was equally effective.

Monoclonal antibodies in diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR), as one of the main complications of diabetes, is among the leading causes of blindness and visual impairment worldwide.

AREAS COVERED

Current clinical therapies include photocoagulation, vitrectomy, and anti-vascular endothelial growth factor (VEGF) therapies. Bevacizumab and ranibizumab are two monoclonal antibodies (mAbs) inhibiting angiogenesis. Intravitreal ranibizumab and bevacizumab can decrease the rate of blindness and retinal thickness, and improve visual acuity whether as monotherapy or combined with other treatments. They can increase the efficacy of other treatments and decrease their adverse events. Although administered intravitreally, they also might enter the circulation and cause systemic effects. This study is aimed to review our current knowledge about mAbs, bevacizumab and ranibizumab, in DR including superiorities, challenges, and limitations. Meanwhile, we tried to shed light on new ideas to overcome these limitations. Our latest search was done in April 2021 mainly through PubMed and Google Scholar. Relevant clinical studies were imported.

EXPERT OPINION

Future direction includes detection of more therapeutic targets considering other components of DR pathophysiology and shared pathogenesis of DR and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, the treat-and-extend regimen, and new ways of drug delivery and other routes of ocular drug administration.

Predictive Biomarkers of Age-Related Macular Degeneration Response to Anti-VEGF Treatment

Age-related macular degeneration (AMD) is an incurable disease associated with aging that destroys sharp and central vision. Increasing evidence implicates both systemic and local inflammation in the pathogenesis of AMD. Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is currently the first-line therapy for choroidal neovascularization in AMD patients. However, a high number of patients do not show satisfactory responses to anti-VEGF treatment after three injections. Predictive treatment response models are one of the most powerful tools for personalized medicine. Therefore, the application of these models is very helpful to predict the optimal treatment for an early application on each patient. We analyzed the transcriptome of peripheral blood mononuclear cells (PBMCs) from AMD patients before treatment to identify biomarkers of response to ranibizumab. A classification model comprised of four mRNAs and one miRNA isolated from PBMCs was able to predict the response to ranibizumab with high accuracy (Area Under the Curve of the Receiver Operating Characteristic curve = 0.968), before treatment. We consider that our classification model, based on mRNA and miRNA from PBMCs allows a robust prediction of patients with insufficient response to anti-VEGF treatment. In addition, it could be used in combination with other methods, such as specific baseline characteristics, to identify patients with poor response to anti-VEGF treatment to establish patient-specific treatment plans at the first visit.

Intravitreal anti-VEGF therapy is not associated with a higher risk of all-cause mortality in patients with macular oedema caused by posterior segment vascular diseases

PURPOSE

To examine whether real-world clinical patients with macular oedema (MO) receiving intravitreal antivascular endothelial growth factor (VEGF) therapy have a higher mortality compared with a matched reference population.

METHODS

A population-based, retrospective cohort study of 26 386 patients from Finland, from January 1, 2001, to December 31, 2017. Index patients were identified through the Caring Epidemiology Project database, receiving at least one intravitreal anti-VEGF injection for wet age-related macular degeneration (AMD, n = 2243, 48.61%), diabetic MO (n = 744, 16.12%), MO due to retinal vascular occlusion (n = 589, 12.77%), or other MO (n = 1038, 22.5%). For each individual treated with intravitreal injection (n = 4614), five age- , sex- , calendar year- and hospital district- matched control individuals (n = 21 772) were chosen. Baseline data of chronic conditions were available. All-cause and cause-specific mortality was analysed using Cox´s proportional hazards model.

RESULTS

In general, the anti-VEGF treated patients had a higher prevalence of systemic conditions, including diabetes (60.1% vs. 46.8%, p < 0.001), chronic hypertension (38.4% vs. 34.6%, p < 0.001), in hospital-treated ischaemic heart disease (23.1% vs. 21.5%, p = 0.014), and glaucoma (11.1% vs. 6.3%, p < 0.001) than controls. There was no difference in all-cause mortality between the anti-VEGF treated patients and matched controls (p = 0.62). In unadjusted Kaplan-Meier analysis of wet AMD subgroup, all-cause mortality was lower in anti-VEGF treated patients than matched controls (p = 0.015), but adjusted Cox´s proportional hazards model showed no difference in the risk of all-cause mortality (HR 0.85, 95% CI 0.66-1.09).

CONCLUSIONS

Intravitreal anti-VEGF therapy was not associated with an increase in the risk of mortality in patients with MO compared with age- and sex-matched controls.

Identification and quantification of fibrotic areas in the human retina using polarization-sensitive OCT

Subretinal fibrosis is one of the most prevalent causes of blindness in the elderly population, but a true gold standard to objectively diagnose fibrosis is still lacking. Since fibrotic tissue is birefringent, it can be detected by polarization-sensitive optical coherence tomography (PS-OCT). We present a new algorithm to automatically detect, segment, and quantify fibrotic lesions within 3D data sets recorded by PS-OCT. The algorithm first compensates for the birefringence of anterior ocular tissues and then uses the uniformity of the birefringent optic axis as an indicator to identify fibrotic tissue, which is then segmented and quantified. The algorithm was applied to 3D volumes recorded in 57 eyes of 57 patients with neovascular age-related macular degeneration using a spectral domain PS-OCT system. The results of fibrosis detection were compared to the clinical diagnosis based on color fundus photography (CFP), and the precision of fibrotic area measurement was assessed by three repeated measurements in a sub-set of 15 eyes. The average standard deviation of the fibrotic area obtained in eyes with a lesion area > 0.7 mm2 was 15%. Fibrosis detection by CFP and PS-OCT agreed in 48 cases, discrepancies were only observed in cases of lesion area < 0.7 mm2. These remaining discrepancies are discussed, and a new method to treat ambiguous cases is presented.

Visual Outcomes after Anti-VEGF Therapy for Exudative Age-Related Macular Degeneration in a Real-Life Setting

BACKGROUND

To report visual outcomes of anti-vascular endothelial growth factor (anti-VEGF) therapy for exudative age-related macular degeneration (AMD) in a real-life setting.

PATIENTS AND METHODS

Retrospective case series of consecutive patients treated with either ranibizumab and/or aflibercept for monolateral or bilateral exudative AMD. A physician established the indication for treatment and administered the injections. An independent physician confirmed the indication for primary treatment. A Pro Re Nata and a Treat and Extend regimen were used. Assessment of subretinal and/or intraretinal fluid, retinal hemorrhage and increase in pigment epithelial detachment served as criteria for further treatment decisions. Visual acuity (VA) was measured in ETDRS letters at each examination and then analyzed using a specialized software. Evolution of mean VA was considered for all study eyes and subgroups of eyes with an initial VA ≥ 70 ETDRS letters (subgroup 1) and ≤ 69 ETDRS letters (subgroup 2).

RESULTS

A total of 102 eyes of 76 patients (30 men, mean age 75.9 years; 46 women, mean age 81.5 years) were included. Subgroup 1 consisted of 47 eyes, and subgroup 2 of 55 eyes. Mean follow-up was 55 months (range 6 to 150 months). For the entire collective as for subgroups 1 and 2, the mean VA was 64, 77, or 51 ETDRS letters at baseline. Mean VA improved at month 12 (68, 80, or 58 ETDRES letters) and then slowly decreased over time until month 150 (62, 72, or 54 ETDRS letters). Maximum improvement of + 5, + 3, or, + 9 ETDRS letters occurred after 9, 8, or 10 months of follow-up. Atrophy and fibrosis were mainly responsible for VA decrease. Ten serious adverse events were reported to Swissmedic: two cases of cardiovascular events and eight cases of intraocular inflammation.

CONCLUSIONS

Anti-VEGF therapy carried out in a real-life setting shows good VA outcomes with a favorable safety profile.

A Cost-Benefit Analysis of VEGF-Inhibitor Therapy for Neovascular Age-Related Macular Degeneration in the United States

PURPOSE

To perform a societal cost-benefit analysis comparing intravitreal bevacizumab (Avastin), ranibizumab (Lucentis), and aflibercept (Eylea) monotherapies for treating neovascular age-related macular degeneration (NVAMD).

DESIGN

Cost-benefit analysis.

METHODS

Center for Value-Based Medicine using published clinical trial and Medicare data.

PATIENT POPULATION

168,400 estimated 2018 U.S. patients with new-onset NVAMD. Procedure(s): cost-benefit analysis using 2018 U.S. real dollars.

OUTCOME MEASUREMENTS

11-year direct ophthalmic medical costs expended for bevacizumab, ranibizumab, and aflibercept monotherapies were compared with ophthalmic and nonophthalmic direct medical, direct nonmedical, and indirect medical (productivity) costs saved by the therapies.

RESULTS

Bevacizumab monotherapy had an individual, 11-year $14,772 treatment cost and net $357,680 societal return (11-year 2,421% return on investment [ROI]). Ranibizumab therapy cost $106,582 and returned $265,870 to society (249% ROI), whereas aflibercept treatment cost $61,811 and returned $310,611 to society (503% ROI). The 2018 NVAMD overall treatment cohort, 11-year net societal gain was $28.5 billion to patients and insurers, with $24.2 billion (84.9%) coming from bevacizumab therapy, $0.7 billion (2.5%) from ranibizumab therapy, and $3.6 billion (12.6%) from aflibercept therapy. Substituting bevacizumab for ranibizumab and aflibercept in the 2018 new-onset NVAMD patients would save an estimated $1.343 billion over 11 years. Vascular endothelial growth factor-inhibitor (VEGF-I) therapy in 2018 should contribute $12.2 billion to the Gross Domestic Product over 11 years. Late treatment would decrease this by 78% to $2.7 billion.

CONCLUSIONS

Intravitreal NVAMD bevacizumab, ranibizumab and aflibercept monotherapies accrue considerable financial, ROIs to patients and insurers as they increase national wealth.

Comparative efficacy and safety of different regimens of ranibizumab for neovascular age-related macular degeneration: a network meta-analysis of randomised controlled trials

OBJECTIVE

To give a comprehensive efficacy and safety ranking of different therapeutic regimens of ranibizumab for neovascular age-related macular degeneration (nAMD).

DESIGN

A systematic review and network meta-analysis.

METHODS

The PubMed, Embase, Cochrane Central Register of Controlled Trials, and other clinical trial registries were searched up to 1 October 2019 to identify related randomised controlled trials (RCT) of different regimens of ranibizumab for nAMD. The primary efficacy outcome was the changes of best-corrected visual acuity (BCVA) at 1 year, the primary safety outcome was the incidence of severe ocular adverse events. Secondary outcomes such as changes of central retinal thickness (CRT) were evaluated. We estimated the standardised mean difference (SMD), ORs, 95% CIs, the surface under the cumulative ranking curves and the mean ranks for each outcome using network meta-analyses with random effects by Stata 14.0.

RESULTS

We identified 26 RCTs involving 10 821 patients with nAMD randomly assigned to 21 different therapeutic regimens of ranibizumab or sham treatment. Ranibizumab 0.5 mg (treat and extend, T&E) is most effective in terms of changes of BCVA (letters, SMD=21.41, 95% CI 19.86 to 22.95) and three or more lines of BCVA improvement (OR=2.83, 95% CI 1.27 to 4.38). However, it could not significantly reduce retreatment times compared with monthly injection (SMD=-0.94, 95% CI -2.26 to 0.39). Ranibizumab 0.5 mg (3+pro re nata)+non-steroidal anti-inflammatory drugs (NSAIDs) is most effective in reducing CRT and port delivery system of ranibizumab (100 mg/mL) could reduce the number of retreatment most significantly. All regimes have no more risk of severe ocular complications (including vitreous haemorrhage, rhegmatogenous retinal detachment, endophthalmitis, retinal tear and retinal pigment epithelium tear) or cardiocerebral vascular complications.

CONCLUSIONS

Ranibizumab 0.5 mg (T&E) is most effective in improving the visual outcome. The administration of topical NSAIDs could achieve additional efficacy in CRT reduction and visual improvement. Both interventions had acceptable risks of adverse events.

ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR DOSING AND EXPECTED ACUITY OUTCOME AT 1 YEAR

PURPOSE

To determine the dose-response characteristics of the antivascular endothelial growth factor agents ranibizumab and aflibercept in neovascular age-related macular degeneration using published randomized trials and observational series.

METHODS

Literature review of published series from 2006 to 2018 as determined from electronic searches of PubMed and the Cochrane Library. Data extracted included treatment strategy, frequency, and first year visual acuity response. Monthly or bimonthly treatment schedules were classified as Fixed, pro re nata studies as PRN, treat and extend as TE, and when no strategy was listed, as Variable.

RESULTS

Of 2062 citations retrieved, 96 were deemed eligible; these 96 citations provided 120 data points of dose frequency versus visual acuity change in Year 1 of treatment. The dose-response curve was nonlinear, but a log transform of the number of injections per year yielded a linear relationship defined by the expression, Letters of Improvement = -6.66 + 15.7*log (number of injections Year 1). After accounting for the number of injections neither the drug used (ranibizumab or aflibercept) nor the strategy used (Fixed, pro re nata, treat and extend, or Variable) were significant predictors of acuity change. As a group, studies using the pro re nata approach had the lowest number of injections and the worst acuity improvements as a treatment strategy.

CONCLUSION

There seems to be a predictable, mathematically defined relationship between dose frequency and visual acuity change at 1 year in neovascular age-related macular degeneration. The performance of current treatment efforts, as suggested by reported series and Medicare claims data, seems to be substandard.

Randomized Controlled Trial of a Spectacle Lens for Macular Degeneration

SIGNIFICANCE

E-Scoop, a spectacle lens, provides no clinically relevant improvements on quality of life, visual acuity, and contrast sensitivity for patients with AMD. Because patients' burden is high and therapeutic options are scarce, the incentive to develop effective vision rehabilitation interventions remains.

PURPOSE

Patients with AMD experience low quality of life due to vision loss, despite angiogenesis inhibitor interventions that slow down progression for some patients. E-Scoop, which includes low-power prisms, 6% magnification, yellow tint, and antireflection coating, might aid in daily activities by improving distance viewing. Separately, these features have little proven effectiveness. E-Scoop has not been formally tested. This study aimed to determine the impact of E-Scoop on quality of life and the effect on visual acuity and contrast sensitivity.

METHODS

In this randomized controlled, open-label trial, 190 of 226 eligible patients were included. The primary outcome was quality of life measured with the 25-item National Eye Institute Visual Function Questionnaire. Secondary outcomes were visual acuity and contrast sensitivity. The follow-up for quality of life was after 6 weeks for controls and after 3 weeks of use for E-Scoop wearers. The visual measures were repeated after 6 weeks, with optimal refractive correction, with and without E-Scoop.

RESULTS

Randomization resulted in 99 E-Scoop and 86 control group patients for intention-to-treat analysis. No differential change was found between the E-Scoop and control groups on the 25-item National Eye Institute Visual Function Questionnaire using Rasch analysis (Cohen d = -0.07, P = .53). Statistically significant but small effects were found in favor of E-Scoop on binocular visual acuity (mean difference, 0.05 logMAR [2.5 letters, P < .001]) and contrast sensitivity (mean difference, 0.10 logCS [2 letters, P < .001]).

CONCLUSIONS

No effect of E-Scoop on quality of life was found. E-Scoop showed effects that were statistically significant, although not clinically meaningful and within typical variability, on visual measures.

Short-term choroidal vascular changes after aflibercept therapy for neovascular age-related macular degeneration

Introduction

The purpose of this study was to evaluate choroidal vascular changes in patients with neovascular age-related macular degeneration (nAMD) treated with aflibercept injection over a 3-month period.

Methods

Enhanced depth imaging optical coherence tomography scans of 60 eyes with treatment-naïve nAMD and 60 unaffected fellow eyes were retrospectively analyzed. Data was collected at baseline and after 3 monthly intravitreal injections of aflibercept. The ImageJ software was used to binarize OCT scans and measure total choroid area (TCA), luminal area (LA), and stromal area (SA). Choroidal vascularity index (CVI) was defined as the ratio of LA to TCA.

Results

After treatment, subfoveal choroidal thickness (CT) in nAMD eyes significantly decreased from 210. 6 ± 61.6 to 194.6 ± 58.7 μm (P < 0.001), TCA from 1.620 ± 0.502 to 1.500 ± 0.451 mm² (P < 0.001), LA from 1.075 ± 0.335 to 0.985 ± 0.307 mm² (P < 0.001), SA from 0.545 ± 0.176 to 0.516 ± 0.153 mm² (P = 0.005), and CVI from 66.36 ± 2.89 to 65.46 ± 2.87% (P = 0.009). The decrease of CVI after treatment was significantly correlated with baseline CVI (Rs = 0.466, P < 0.001), but not with the change in BCVA and presence of dry macula after treatment (always P > 0.05).

Conclusion

Choroidal thickness and vascularity significantly decreased after treatment with aflibercept in nAMD eyes. Besides the pharmacologic effect on the neovascular lesion, aflibercept may induce vascular changes also on the underlying choroid.

Cost-Utility Analysis of VEGF Inhibitors for Treating Neovascular Age-Related Macular Degeneration

PURPOSE

To perform 11- and 2-year health care sector (ophthalmic) and societal cost perspective reference case, cost-utility analyses comparing bevacizumab, ranibizumab, and aflibercept monotherapies for neovascular age-related macular degeneration (NVAMD).

DESIGN

Cost-utility analysis.

METHODS

The authors performed 11-year and 2-year ophthalmic and societal cost perspective, cost-utility analyses comparing bevacizumab, ranibizumab, and aflibercept monotherapies for neovascular age-related macular degeneration (NVAMD). We employed patient utilities, bilateral outcomes, 2018 U.S. dollars, vision-related mortality, a Medicare fee schedule, and CATT (Comparison of Age-Related Macular Degeneration Treatments) study and VIEW (VEGF Trap-Eye: Investigation of Efficacy and Safety in Wet AMD) trial. Cochrane data were also used.

SETTING

Center for Value-Based Medicine. Patient/study population: patients with NVAMD.

INTERVENTION

Cost-utility analyses using published data. Data-modeled 10-year vision outcomes were modeled forward to year 11.

MAIN OUTCOME MEASUREMENT

These included cost-utility ratios (CURs), costs, and quality-adjusted life-years (QALYs) gained. $100,00/QALY was considered the US cost-effectiveness upper limit.

RESULTS

Bevacizumab and ranibizumab each conferred an 11-year, 1.339 QALY gain versus observation. Aflibercept conferred a 1.380 QALY gain. Aflibercept conferred greater QALY gain for less cost than ranibizumab but was not cost-effective compared to bevacizumab ($1,151,451/QALY incremental CUR). The average ophthalmic cost perspective CUR for bevacizumab was $11,033/QALY, $79,600/QALY for ranibizumab, and $44,801/QALY for aflibercept. Eleven-year therapies saved a 1.0 year-of-life loss without treatment from the 11.0-year life expectancy. Early treatment was 138%-149% more cost-effective than late treatment. Two-year therapy prevented a 1-month-of-life loss, and revealed bevacizumab, ranibizumab, and aflibercept conferred 0.141, 0.141, and 0.164 QALY gains, respectively, with corresponding average CURs of $40,371/QALY, $335,726/QALY, and $168,006/QALY, respectively.

CONCLUSIONS

From an ophthalmic (medical) cost perspective, bevacizumab, ranibizumab, and aflibercept NVAMD monotherapies were all cost-effective over 11 years, with bevacizumab 6.21× more cost-effective than ranibizumab and 3.06× more cost-effective than aflibercept. Two-year modeling revealed bevacizumab was cost-effective, whereas ranibizumab and aflibercept were not. Early treatment was critical for obtaining optimal vision and cost-effectiveness, as is long-term follow-up and adherence to treatment.

The long-term effects of anti-vascular endothelial growth factor therapy on the optical coherence tomography angiographic appearance of neovascularization in age-related macular degeneration

Background

The short-term effects of anti-vascular endothelial growth factor (anti-VEGF) treatment on macular neovascularization (MNV) morphology is well described, but long-term studies on morphologic changes and correlation of such changes to the type of MNV have not been conducted. This study aims to determine if different types of MNVs in neovascular AMD (nAMD) behave differently with anti-VEGF treatment as visualized on optical coherence tomography angiography (OCTA).

Methods

Treatment-naïve nAMD patients were retrospectively screened for baseline and follow-up OCTA imaging 10 or more months after initial treatment. Images were graded for MNV type, area, activity, mature versus immature vessels, vessel density, presence of atrophy, atrophy location and area. Growth rate was calculated as the percent change in lesion area from baseline over the years of follow-up. In addition, the occurrence of complete regression and the percent of lesions that grew, remained stable, and shrunk per type was also evaluated.

Results

Forty-three eyes from 43 patients with a mean follow-up of 2 years were evaluated. On structural OCT, 26 lesions were classified as pure type 1 MNVs, 12 MNVs had a type 2 component, and 5 MNVs had a type 3 component. Of these cases, 2 mixed-type MNVs were considered to have completely regressed. There was no significant differences in MNV area and growth rate between type 1 and type 2 lesions, but all cases of type 3 lesions shrunk in the follow-up period. There was no correlation between the number of injections per year and growth rate, endpoint MNV area or endpoint activity status for any MNV type. There was no significant association between the development of atrophy and the number of injections, baseline MNV area, baseline vessel density, or lesion growth rate.

Conclusions

In nAMD, complete regression of an MNV network exposed to anti-VEGF is rare. This work emphasizes the role of anti-VEGF as anti-leakage rather than vascular regression agents in nAMD.

Cost-minimization Analysis of Ranibizumab versus Aflibercept in the Treatment of Neovascular Age-related Macular Degeneration in Colombia

BACKGROUND

In 2020 Colombia may expect to have close to 231,700 patients with neovascular age-related macular degeneration (ARMD). Treatment of neovascular ARMD involves the sequential Intra-vitreal injections of anti-vascular endothelial growth factor (anti-VEGF therapy) medications. The efficacy and safety of anti-VEGF therapy on a treat-and-extend (T&E) dosing scheme are similar when ranibizumab or aflibercept are administered. Objective : A cost-minimization analysis from the payer`s perspective in Colombia projects treatment expenses of anti-VEGF therapy using aflibercept or ranibizumab on T&E regimens for the treatment of neovascular ARMD. Methods : A model projects the expenses of the compared treatment regimens for two and five-year periods beginning on February 2020. The model used information from clinical trials, case series and meta-analyses on the compared treatment regimens, demographic, epidemiologic and economic data originated from the Colombian government sources. A 3% discount rate was applied. Results : Projected cost differences in favor of ranibizumab after two and five-year treatment periods beginning February 2020 could be close to U.S. $ 4,861 and U.S $ 7,241 per treated eye, respectively. If all patients with unilateral and bilateral neovascular ARMD in Colombia were to receive appropriate anti-VEGF therapy for two years, the projected expected cost difference in favor of ranibizumab could be close to U.S. $ 462,717,092 dollars. Conclusion : Within the Colombian healthcare setting anti-VEGF therapy on a T&E regimen utilizing ranibizumab for neovascular ARMD may be cost-saving compared with employing aflibercept. Despite cost favorability, ranibizumab should not be the only therapeutic option since in clinical practice alternatives are required.

Pharmacological Advances in the Treatment of Age-related Macular Degeneration

Age-related macular degeneration is an acquired degenerative disease that is responsible for severe loss of vision in elderly people. There are two types: dry age-related macular degeneration and wet age-related macular degeneration. Its treatment has been improved and tries to be tailored in the future. The aim of this review is to summarize the pharmacological advances in the treatment of age-related macular degeneration. Regarding dry AMD, there is no effective treatment to reduce its progression. However, some molecules such as lampalizumab and eculizumab were under investigation, although they have shown low efficacy. Herein, in an attempt to prevent dry AMD progression, the most important studies suggested increasing the antioxidants intake and quitting the smoke habit. On the other hand, wet AMD has more developed treatment. Nowadays, the gold standard treatment is anti-VEGF injections. However, more effective molecules are currently under investigation. There are different molecules under research for dry AMD and wet AMD. This fact could help us treat our patients with more effective and lasting drugs but more clinical trials and safety studies are required in order to achieve an optimal treatment.

Anti-VEGF-A/ANG2 combotherapy limits pathological angiogenesis in the eye: a replication study

Neovascular and inflammatory retinal diseases including wet age‐related macular degeneration (AMD) can cause severe vision loss among the elderly. Simultaneous neutralization of vascular endothelial growth factor‐A (VEGF‐A) and angiopoietin 2 (ANG2) is envisioned as a novel candidate approach to treat wet AMD with better efficacy. However, earlier published data from a genetic mouse model showed data aberrations (Regula et al, 2016). In this issue of EMBO Molecular Medicine, Foxton et al (2019) have provided compelling evidence replicating the data and confirming the overall concept that VEGF‐A/ANG2 combotherapy is effective in suppressing retinal neovascularization.

Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

Purpose

Subretinal fibrosis (SRFib) is an important cause of permanent loss-of-vision diseases with submacular neovascularization, but a reliable diagnostic method is currently missing. This study uses polarization-sensitive optical coherence tomography (PS-OCT) to detect SRFib within retinal lesions by measurement of its birefringent collagen fibers.

Methods

Twenty-five patients were enrolled with retinal pathology in one or both eyes containing (1) suspected SRFib, (2) lesions suspected not to be fibrotic, or (3) lesions with doubtful presence of SRFib. All eyes were evaluated for SRFIb using conventional diagnostics by three retinal specialists. PS-OCT images were visually evaluated for SRFib based on cumulative phase retardation, local birefringence, and optic axis uniformity.

Results

Twenty-nine eyes from 22 patients were scanned successfully. In 13 eyes, SRFib was diagnosed by all retinal specialists; of these, 12 were confirmed by PS-OCT and one was inconclusive. In nine eyes, the retinal specialists expected no SRFib, which was confirmed by PS-OCT in all cases. In seven eyes, the retinal specialists’ evaluations were inconsistent with regard to the presence of SRFib. PS-OCT confirmed the presence of SRFib in four of these eyes and the absence of SRFib in two eyes and was inconclusive in one eye.

Conclusions

In 21 out of 22 eyes, PS-OCT confirmed the evaluation of retinal specialists regarding the presence of SRFib. PS-OCT provided additional information to distinguish SRFib from other tissues within subretinal neovascular lesions in 6 out of 7 eyes.

Translational Relevance

PS-OCT can identify and quantify SRFib in doubtful cases for which a reliable diagnosis is currently lacking.

Timing of Peak Vision Gains in Patients with Neovascular Age-Related Macular Degeneration Treated with Ranibizumab

PURPOSE

To investigate whether time to peak best-corrected visual acuity (BCVA) was predictive of magnitude of BCVA changes at study end in patients with neovascular age-related macular degeneration (nAMD) who received ranibizumab and assess whether patient baseline characteristics and on-study events were predictive of time to peak BCVA.

DESIGN

Exploratory analysis of data from HARBOR (ClinicalTrials.gov identifier, NCT00891735).

PARTICIPANTS

Treatment-naïve patients 50 years of age or older with subfoveal nAMD.

METHODS

Data by ranibizumab dose were pooled; data by dosing schedule (pro re nata [PRN] and monthly) were evaluated separately. Time to peak BCVA was the monthly evaluation at which the patient's greatest gain in Early Treatment Diabetic Retinopathy Study (ETDRS) letters from baseline was achieved. Early peakers achieved peak BCVA between day 7 and month 6; late peakers achieved peak BCVA between months 7 and 12, months 13 and 18, and months 19 and 24. Variables evaluated for effect of time to peak BCVA included baseline demographic and clinical characteristics, presence of persistent subretinal fluid (SRF) or intraretinal fluid (IRF), and on-study events (atrophy status, fibrosis, retinal pigment epithelium tears).

MAIN OUTCOME MEASURES

Time to peak BCVA and its predictive value for magnitude of BCVA changes and BCVA at month 24 (study end).

RESULTS

Most patients reached peak BCVA after more than 6 months of treatment: 64% in the PRN group (301/474) and 70% in the monthly groups (327/469). Thirty-six percent and 30% of patients, respectively, peaked early, and 64% and 70%, respectively, peaked late. At month 24, early peakers on average lost vision (PRN, -1.6 ETDRS letters; monthly, -1.9 ETDRS letters). By contrast, late peakers achieved significantly better vision gains from baseline (PRN, 8.5-17.7 ETDRS letters; monthly, 10.1-18.7 ETDRS letters). No differences were found in patient characteristics, persistent SRF or IRF, or on-study events to account for the observed different outcomes between early and late peakers.

CONCLUSIONS

In most treatment-naïve patients with nAMD, vision gains were achieved at a slower rate (>6 months), and a slower response was associated with better vision outcomes after 24 months of ranibizumab. These findings suggest that continued treatment may result in greater vision improvements when consistent anti-vascular endothelial growth factor therapy is maintained over a longer period.

Impact of switching from ranibizumab to aflibercept on the number of intravitreous injection and follow up visit in wet AMD: results of real life ELU study

AIM

To study if one of the two molecules could lead to a lower number of follow up visits and intra-vitreous injection (IVI) with the same efficacy.

METHODS

ELU (or "elected" in French) study is a retrospective study conducted in real life in patients presenting suboptimal response after ranibizumab IVI (phase 1) and secondary switched to aflibercept (phase 2). The number of follow up visits and IVI were compared in both phases. Visual acuity (VA) evolution and "switching" reasons were secondary analyzed.

RESULTS

We retrospectively included data of 33 patients (38 eyes) with age-related macular degeneration (AMD; mean age: 77±7.7y). The number of monthly follow up visits [median (Q1; Q3)]: was significantly lower with aflibercept (phase 2), respectively 1.0 (0.81; 1.49) visits in phase 1, versus 0.79 (0.67; 0.86) visits in phase 2. The median number of monthly IVI also significantly decreased in phase 2, respectively 0.67 (0.55; 0.90) IVI in phase 1, versus 0.55 (0.45; 0.67) IVI in phase 2. The mean VA evolution (VA final-VA initial) was similar in both phases, (P>0.05). Whatever the reason for "switching" (loss of efficacy, tachyphylaxis, tolerance problems), there was no incidence on VA evolution over the time.

CONCLUSION

Our results show that switching from ranibizumab to aflibercept in "suboptimal" patients significantly reduce the number of follow up visits and IVI, with a comparable efficacy. This decrease in visit number could improve patients' quality of life and reduce surgical risk by reducing the number of injections.

Bevacizumab for eye diseases - Legal, regulatory, and ethical overview

Vascular endothelial growth factor (VEGF) inhibitors, ranibizumab, aflibercept, and pegaptanib are approved treatments for certain eye diseases that occurs especially in the elderly. These drugs are mostly inaccessible due to their high cost. Bevacizumab is a VEGF inhibitor, approved for cancer treatment. Being a cheaper alternative, it is extensively used off-label as an intravitreal injection for the treatment of eye diseases. In this article, we have analyzed similarities and differences between bevacizumab and ranibizumab, and potential long-term safety concerns with off-label use of bevacizumab. We also analyzed legal, regulatory, and ethical background of off-label use and provided recommendations to resolve this issue. Based on the extensive clinical data, actions taken, and recommendations provided by agencies such as the National Institute for Health and Care Excellence, International Council of Ophthalmology, United Kingdom and Thailand regulatory agency, intravitreal bevacizumab has adequate evidence for controlled licensing. Claiming better safety for ranibizumab at the expense of nonaffordability cannot be considered a positive risk-benefit scenario. Intravitreal bevacizumab is being used and will continue to be used off-label, if not regulatory controlled. Licensing will ensure the availability of intravitreal bevacizumab to the patients with eye diseases, without any legal or ethical concerns for the clinicians, and will also assist in generating long-term safety data. Safest delivery formulation and dosage form should be considered for approval. Both the regulatory agency and technical experts should join and take critical decision, which will be a big step forward to making a cost-effective drug available to the public.

Neutrophils homing into the retina trigger pathology in early age-related macular degeneration

Age-related macular degeneration (AMD) is an expanding problem as longevity increases worldwide. While inflammation clearly contributes to vision loss in AMD, the mechanism remains controversial. Here we show that neutrophils are important in this inflammatory process. In the retinas of both early AMD patients and in a mouse model with an early AMD-like phenotype, we show neutrophil infiltration. Such infiltration was confirmed experimentally using ribbon-scanning confocal microscopy (RSCM) and IFNλ- activated dye labeled normal neutrophils. With neutrophils lacking lipocalin-2 (LCN-2), infiltration was greatly reduced. Further, increased levels of IFNλ in early AMD trigger neutrophil activation and LCN-2 upregulation. LCN-2 promotes inflammation by modulating integrin β1 levels to stimulate adhesion and transmigration of activated neutrophils into the retina. We show that in the mouse model, inhibiting AKT2 neutralizes IFNλ inflammatory signals, reduces LCN-2-mediated neutrophil infiltration, and reverses early AMD-like phenotype changes. Thus, AKT2 inhibitors may have therapeutic potential in early, dry AMD.

Real-time OCT guidance and multimodal imaging monitoring of subretinal injection induced choroidal neovascularization in rabbit eyes

Choroidal neovascularization (CNV) is a major cause of vision loss that consists of abnormal growth of new blood vessels from the choroidal vasculature. High resolution in vivo imaging of animal models is essential to better elucidate and conduct research on CNV. This study evaluates a novel multimodal imaging platform combining optical coherence tomography (OCT) and photoacoustic microscopy (PAM). Using real-time OCT guidance subretinal injection to induce and multimodality imaging system to monitor CNV over time in rabbit eyes. The significance of our work lies in providing the optimal setting and conditions to make use of the OCT image guided system to improve the consistency and reproducibility of experimental results in subretinal injection induced CNV model in rabbits. For the first time, this study successfully demonstrated the dual-modality PAM-OCT system, without using exogenous contrast agents, can detect and visualize CNV in the rabbit eye with high resolution. This is promising system for diagnosing and monitoring CNV.

Twelve-week dosing with Aflibercept in the treatment of neovascular age-related macular degeneration

Purpose

To review published evidence for a treatment interval extension to ≥12-weeks in neovascular macular degeneration treated with intravitreal Aflibercept.

Methods

A systematic search was performed in the NCBI/PubMed database to identify pro- and retrospective studies retrieved by the key terms <exudative> or <neovascular> and <AMD> or <age-related macular degeneration> AND <intravitreal therapy> AND <Aflibercept> and included all papers that used a treat-and-extend (T&E) protocol including a loading phase of 3 intravitreal anti-VEGF injections and a minimal follow-up of 2 years. Disease stability was defined as the absence of any intraocular and absence or stability of subretinal fluid and pigment-epithelial detachment.

Results

Four studies were identified that reported information pertaining to disease stability or treatment extension beyond 12 weeks under intravitreal Aflibercept therapy including 1,102 eyes in total. Following a T&E protocol, a mean of 62.9% achieved disease stability and a 6.9 letter gain based on 11.9 injections over 24 months of Aflibercept treatment. As much as 43.0% of all eyes or 64.1% of the eyes with stable disease were maintained on ≥12-weekly injection intervals.

Conclusions

A consequent treatment with a null tolerance for intraretinal fluid is prerequisite to induce stability and maintain visual gain after the loading phase. Using Aflibercept in a T&E protocol, disease stability and interval extension to ≥12 weeks were reported in 43% of the eyes by end of the second year with less injections, but similar results as under fix dosing. A lower treatment burden strongly argues for an individualized proactive treatment regimen.

Co-inhibition of PGF and VEGF blocks their expression in mononuclear phagocytes and limits neovascularization and leakage in the murine retina

Background

Age-related macular degeneration (AMD) is a leading cause of visual impairment in the elderly. The neovascular (wet) form of AMD can be treated with intravitreal injections of different anti-vascular endothelial growth factor (VEGF) agents. Placental growth factor (PGF) is another member of the VEGF family of cytokines with pro-angiogenic and pro-inflammatory effects. Here, we aimed to compare single and combined inhibition of VEGF-A and PGF in the laser-induced mouse model of choroidal neovascularization (CNV) with a focus on the effects on retinal mononuclear phagocytes.

Methods

CNV was induced in C57BL/6J mice using a YAG-Laser. Immediately after laser damage antibodies against VEGF-A (aVEGF), anti-PGF (aPGF), aVEGF combined with aPGF, aflibercept, or IgG control were injected intravitreally in both eyes. Three and 7 days after laser damage, the vascular leakage was determined by fluorescence angiography. Lectin staining of retinal and RPE/choroidal flat mounts was used to monitor CNV. In situ mRNA co-expression of Iba1, VEGF and PGF were quantified using in situ hybridization. Retinal and RPE/choroidal protein levels of VEGF and PGF as well as the pro-inflammatory cytokines IL-6, IL1-beta, and TNF were determined by ELISA.

Results

Early (day 3) and intermediate (day 7) vascular leakage and CNV were significantly inhibited by PGF and VEGF-A co-inhibition, most effectively with the trap molecule aflibercept. While VEGF-A blockage alone had no effects, trapping PGF especially with aflibercept prevented the accumulation of reactive microglia and macrophages in laser lesions. The lesion-related mRNA expression and secretion of VEGF-A and PGF by mononuclear phagocytes were potently suppressed by PGF and partially by VEGF-A inhibition. Protein levels of IL-6 and IL1-beta were strongly reduced in all treatment groups.

Conclusions

Retinal inhibition of PGF in combination with VEGF-A prevents vascular leakage and CNV possibly via modulating their own expression in mononuclear phagocytes. PGF-related, optimized strategies to target inflammation-mediated angiogenesis may help to increase efficacy and reduce non-responders in the treatment of wet AMD patients.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1419-2) contains supplementary material, which is available to authorized users.