Bevacizumab for the treatment of neovascular age-related macular degeneration

The state-of-the-art pharmacotherapeutic management of neovascular age-related macular degeneration

INTRODUCTION

Age-related macular degeneration (AMD) is a major cause of central visual loss in the developed world. Although the pathogenesis is not fully understood, vascular endothelial growth factor (VEGF) is considered the most important growth factor involved in angiogenesis and exudation in neovascular AMD eyes. Advances in anti-VEGF agents have changed the treatment approach for wet AMD, allowing better outcomes in visual acuity and retinal anatomy.

AREAS COVERED

The present review describes the main pharmacological and clinical characteristics of anti-VEGF drugs, focusing firstly on the molecules commonly in use and then on the new candidate therapies. We performed a comprehensive literature search using the PubMed database from 1 January 1993 to 1 June 2022, with search terms including anti-VEGF, biosimilar, neovascular macular degeneration, AMD, and safety.

EXPERT OPINION

The management of AMD is still onerous for both the physician and patient due to the great number of required injections. Current research is underway to resolve not only the economic burden but also the discomfort of patients, aiming to develop a drug with a different or a multiple target, increasing the potency whilst maintaining a good safety profile. Furthermore, clinical research is currently investigating different forms of drug administration.

The Pharmacological Effects of Lutein and Zeaxanthin on Visual Disorders and Cognition Diseases

Lutein (L) and zeaxanthin (Z) are dietary carotenoids derived from dark green leafy vegetables, orange and yellow fruits that form the macular pigment of the human eyes. It was hypothesized that they protect against visual disorders and cognition diseases, such as age-related macular degeneration (AMD), age-related cataract (ARC), cognition diseases, ischemic/hypoxia induced retinopathy, light damage of the retina, retinitis pigmentosa, retinal detachment, uveitis and diabetic retinopathy. The mechanism by which they are involved in the prevention of eye diseases may be due their physical blue light filtration properties and local antioxidant activity. In addition to their protective roles against light-induced oxidative damage, there are increasing evidences that L and Z may also improve normal ocular function by enhancing contrast sensitivity and by reducing glare disability. Surveys about L and Z supplementation have indicated that moderate intakes of L and Z are associated with decreased AMD risk and less visual impairment. Furthermore, this review discusses the appropriate consumption quantities, the consumption safety of L, side effects and future research directions.

The methodological quality of systematic reviews comparing intravitreal bevacizumab and alternates for neovascular age related macular degeneration: A systematic review of reviews

OBJECTIVE

To systematically collate and evaluate the evidence from recent SRs of bevacizumab for neo-vascular age related macular degeneration.

MATERIALS AND METHODS

Literature searches were carried out in Medline, Embase, Cochrane databases for all systematic reviews (SRs) on the effectiveness of bevacizumab for neo-vascular age related macular degeneration, published between 2000 and 2013. Titles and abstracts were assessed against the inclusion/exclusion criteria using Joanna Briggs Institute (JBI) study eligibility form. Data was extracted using the JBI data extraction form. The quality of the SRs was assessed using JBI critical appraisal checklist for SRs. Decisions on study eligibility and quality were made by two reviewers; any disagreements were resolved by discussion.

RESULTS

Nine relevant reviews were identified from 30 citations, of which 5 reviews fulfilled the review's inclusion criteria. All 5 reviews showed bevacizumab to be effective for neovascular AMD in the short-term when used alone or in combination with PDT or Pegaptanib. The average quality score of the reviews was 7; 95% confidence interval 6.2 to 7.8 (maximum possible quality score is 10). The selection and publication bias were not addressed in all included reviews. Three-fifth of the reviews had a quality score of 7 or lower, these reviews had some methodological limitations, search strategies were only identified in 2 (40%) reviews, independent study selection and quality assessment of included studies (4 (80%)) were infrequently performed.

CONCLUSION

Overall, the reviews on the effectiveness of intravitreal/systemic bevacizumab for neovascular  age-related macular generation (AMD) received good JBI quality scores (mean score = 7.0 points), with a few exceptions. The study also highlights the suboptimal reporting of SRs on this topic. Reviews with poor methodology may limit the validity of the reported results; hence efforts should be made to improve the design, reporting and publication of SRs across all journals.

Comparison of Neuroprotective Effect of Bevacizumab and Sildenafil following Induction of Stroke in a Mouse Model

To evaluate the effect of bevacizumab and sildenafil on stroke parameters in a mouse model, middle cerebral artery occlusion was induced in male C57Bl/6 mice using an intra-arterial filament method. The filament was removed after 60 minutes, and the mice were immediately given a single intraperitoneal injection of saline, bevacizumab, or sildenafil. An additional group of mice (n = 7) received bevacizumab 6 h after MCAO induction. The mice were euthanized 24 hours later and evaluated for infarct area and brain edema using triphenyltetrazolium chloride staining and ImageJ. In the saline-treated mice (n = 16), total stroke volume was 19.20 ± 6.38 mm³, mean penumbra area was 4.5 ± 2.03 mm³, and hemispheric asymmetry was 106.5%. Corresponding values in the bevacizumab group (n = 19) were 17.79 ± 5.80 mm³, 7.3 ± 3.5 mm³, and 108.6%; in the delayed (6 h) bevacizumab injected mice (n = 7) they were 9.80 ± 8.00 mm³, 2.4 ± 2.0 mm³, and 98.2%; and in the sildenafil group (n = 16) they were 18.42 ± 5.41 mm³, 5.7 ± 2.02 mm³, and 109.9%. The bevacizumab group had a significantly larger mean penumbra area when given immediately and smaller total stroke area in both groups than the saline- (p = 0.03) and sildenafil-treated (p = 0.003) groups. Only delayed bevacizumab group had reduced edema. Bevacizumab, injected immediately or delayed after injury, exerts a neuroprotective/salvage effect, whereas immediate treatment with sildenafil does not. Inflammation may play a role in the neuroprotective effect.

Serum MicroRNAs as Potential Biomarkers of AMD

BACKGROUND

Age-related macular degeneration (AMD) is a major cause of blindness worldwide. Circulating microRNAs (miRNAs) in serum have emerged as novel candidate biomarkers for many diseases. The aim of the present study was to identify a serum microRNA (miRNA) expression profile specific for dry and wet forms of AMD.

MATERIAL AND METHODS

Serum miRNA expression was first screened using TaqMan® Human MicroRNA Array A (Applied Biosystems). An extensive, self-validated, individual, quantitative RT-PCR (qRT-PCR) study was then performed on a cohort of 300 AMD patients (150 wet form and 150 dry form) and 200 controls. The Mann-Whitney U test and nonparametric Spearman's rank correlation coefficient were used for statistical analysis.

RESULTS

miRNA expression analysis revealed increased expression of miR661 and miR3121 in serum of patients with dry AMD and miR4258, miR889, and Let7 in patients with wet form. Expression of analyzed miRNA was not observed or remained at low level in controls.

CONCLUSIONS

Differences in miRNA serum profile exist between patients with wet and dry form of AMD, which indicates miRNAs as potential biomarkers of AMD. Further studies should be performed to confirm its significance in clinical practice.

Ranibizumab: a review of its use in the treatment of neovascular age-related macular degeneration

Ranibizumab (Lucentis(®)), an inhibitor of all vascular endothelial growth factor (VEGF) A isoforms, is approved for the intravitreal treatment of neovascular age-related macular degeneration (AMD). In pivotal trials, monthly injections of ranibizumab were superior to verteporfin photodynamic therapy in the treatment of predominantly classic choroidal neovascularization (CNV) due to neovascular AMD (ANCHOR) and sham in the treatment of minimally classic or occult CNV due to neovascular AMD (MARINA). Monthly or less frequent injections of ranibizumab are generally well tolerated and associated with low rates of ocular and systemic serious adverse events (SAEs). Less frequent dosing has been evaluated with the aim of reducing the burden, risk and cost of monthly injections. In the landmark CATT trial, monthly monitoring and retreatment as-needed with ranibizumab was equivalent to monthly treatment in terms of the vision gain at 1 year, but reduced the number of injections (and the related cost) by approximately one-half. In head-to-head comparisons, aflibercept administered bimonthly was noninferior to ranibizumab administered monthly (VIEW 1 and 2), bevacizumab administered monthly was equivalent to ranibizumab administered monthly (CATT), and bevacizumab administered as-needed was equivalent to ranibizumab administered as-needed (CATT). Bevacizumab is widely used (off-label) for economic reasons; while it was less costly than ranibizumab, it was associated with more systemic SAEs. Notwithstanding the availability of other similarly effective anti-VEGF therapies that are approved (aflibercept) or unapproved (bevacizumab), ranibizumab continues to set the standard as regards the totality of evidence from randomized clinical trials demonstrating its efficacy and tolerability (particularly that of the monthly regimen) in the treatment of neovascular AMD.

Efficacy of Ethanol Extract of Fructus lycii and Its Constituents Lutein/Zeaxanthin in Protecting Retinal Pigment Epithelium Cells against Oxidative Stress: In Vivo and In Vitro Models of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a major cause of blindness worldwide. Oxidative stress plays a large role in the pathogenesis of AMD. The present study was to evaluate the effects of Fructus lycii ethanol extract on AMD in mice and to investigate whether combination of lutein and zeaxanthin, two carotenoid pigments in Fructus lycii, could protect human retinal pigment epithelial ARPE-19 cells treated with hydrogen peroxide (H₂O₂) in vitro. We found that severe sediment beneath retinal pigment epithelium and thickened Bruch membrane occurred in AMD mice. However, Fructus lycii ethanol extract improved the histopathologic changes and decreased the thickness of Bruch membrane. Furthermore, the gene and protein expression of cathepsin B and cystatin C was upregulated in AMD mice but was eliminated by Fructus lycii ethanol extract. Investigations in vitro showed that ARPE-19 cell proliferation was suppressed by H₂O₂. However, lutein/zeaxanthin not only stimulated cell proliferation but also abrogated the enhanced expression of MMP-2 and TIMP-1 in H₂O₂-treated ARPE-19 cells. These data collectively suggested that Fructus lycii ethanol extract and its active components lutein/zeaxanthin had protective effects on AMD in vivo and in vitro, providing novel insights into the beneficial role of Fructus lycii for AMD therapy.