Anti-VEGF-resistant subretinal fluid is associated with better vision and reduced risk of macular atrophy

Application and mechanism of anti-VEGF drugs in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. The incidence rate increases with age in people over 50 years of age. With the advent of China’s aging society, the number of patients is increasing year by year. Although researchers have done a lot of basic research and clinical research on the pathogenesis and treatment of AMD in recent years, the pathogenesis of AMD is still controversialdue to the complexity of the disease itself. AMD is the primary cause of blindness in the elderly over 50 years old. It is characterized by the formation of choroidal neovascularization (CNV) and the over secretion of vascular endothelial growth factor (VEGF) as its main mechanism, which can eventually lead to vision loss or blindness. The occurrence and development of AMD is an extremely complex process, in which a large number of regulatory factors and cytokines are involved. Most of the existing treatments are for its concomitant CNV. Targeted VEGF drugs for neovascularization, such as Lucentis and Aflibercept, are the first-line drugs for AMD. Their application has greatly reduced the blinding rate of patients. However, there are still some patients who have no response to treatment or cannot maintain their vision after long-term treatment. Frequent injection also increases the risk of complications and economic burden. In order to further improve the quality of life and long-term prognosis of AMD patients, a variety of new treatmentshave been or will be applied in clinic, including combined treatment with the same or different targets to improve the curative effect, change or simplify the mode of medication, inhibit VEGF receptor tyrosine protein kinase and so on. This article provides a brief review of the research progress of anti-VEGF drugs and their mechanisms for the treatment of AMD, it is expected to provide a better treatment plan for AMD treatment.

Association Between Visual Acuity and Residual Retinal Fluid Following Intravitreal Anti-Vascular Endothelial Growth Factor Treatment for Neovascular Age-Related Macular Degeneration: A Systematic Review and Meta-analysis

Importance

The association between residual subretinal fluid (SRF) and intraretinal fluid (IRF) and visual acuity following anti-vascular endothelial growth factor (VEGF) treatment is not well understood.

Objective

To examine the association of residual retinal fluid, SRF, and IRF with visual acuity following anti-VEGF treatment in patients with neovascular age-related macular degeneration (nAMD).

Data Sources

A systematic literature search was performed from January 2005 to August 2021 using Ovid MEDLINE, Embase, and the Cochrane Library.

Study Selection

Peer-reviewed articles reporting on visual acuity stratified by the presence or absence of any residual SRF, IRF, or any retinal fluid at last study observation after intravitreal bevacizumab, ranibizumab, aflibercept, or brolucizumab in patients with nAMD were included. Studies that were noncomparative, included fewer than 10 eyes, or reported on other anti-VEGF agents were excluded.

Data Extraction and Synthesis

Two independent reviewers conducted data extraction and synthesis. The Cochrane risk of bias tool 2 and ROBINS-I were used to assess risk of bias and GRADE evaluation was conducted to assess certainty of evidence.

Main Outcomes and Measures

Primary outcomes were BCVA at last study observation, change in BCVA from baseline, and retinal thickness at last study observation.

Results

In this systematic review and meta-analysis, 11 studies (6 randomized clinical trials [RCTs]) comprising 3092 eyes were included in our analysis. Across all included studies, the BCVA of eyes with residual SRF was better than eyes without SRF (weighted mean difference [WMD], 3.1 letter score; 95% CI, 0.05 to 6.18; P = .05; GRADE, low certainty of evidence; 6 studies; 1931 eyes) but similar in RCTs (WMD, 2.7 letter score; 95% CI, -2.40 to 7.84; P = .30; GRADE, low certainty of evidence; 3 studies; 1406 eyes). The BCVA of eyes with residual IRF was worse than that of eyes without IRF (WMD, -8.2 letter score; 95% CI, -11.79 to -4.50; P < .001; GRADE, low; 7 studies; 2114 eyes).

Conclusions and Relevance

The findings suggest that the presence of residual SRF was associated with slightly better BCVA at last study observation; however, baseline differences in BCVA existed and this conclusion was primarily driven by 1 study. The presence of residual IRF was associated with substantially worse BCVA at last study observation and less improvement of BCVA from baseline. The conclusions are limited by the inclusion of data from observational studies, heterogeneity, and a low certainty of evidence.

Subretinal fluid disturbs the retinal venous blood flow in central serous chorioretinopathy

The significance of subretinal fluid in the retinal blood flow is unclear. Here, we evaluated the association between subretinal fluid (SRF) and retinal blood flow in eyes with central serous chorioretinopathy (CSC) using a retinal functional imager (RFI) and optical coherence tomography angiography (OCTA). In this retrospective case–control study involving 26 eyes from 18 CSC patients and 25 eyes from 21 age- and sex-matched controls, we found that the CSC group showed significant differences from the control group in terms of the retinal venule blood flow velocity (3.60 ± 0.43 vs 3.96 ± 0.56 mm/s; p = 0.030), retinal venule blood flow rate (8.75 ± 2.67 vs 12.51 ± 7.12 nl/s; p = 0.040), and the diameter of retinal venules (118.26 ± 14.25 vs 126.92 ± 35.31 μm; p = 0.045). Linear regression analysis showed that SRF thickness accounted for a 36.9% reduction in venous BFR (p = 0.013). The difference in the O₂ saturation between retinal arteries and veins was greater in the CSC group. There was no correlation between SRF thickness and capillary densities in OCTA. Our findings suggest that disturbance in venous return and the associated altered oxygen may be significant changes in the retinal blood flow dynamics in eyes with SRF.

Hypothetical Switch of Anti-Vascular Endothelial Growth Factor in Neovascular Age-Related Macular Degeneration: An ARIES Post Hoc Analysis

Introduction

Switching to an alternative anti-vascular endothelial growth factor (anti-VEGF) agent has been suggested for patients with neovascular age-related macular degeneration (nAMD) who have a suboptimal response to initial therapy. However, post hoc analyses of some studies have shown that continuation of initial anti-VEGF therapy is, in many cases, associated with stable visual outcomes or gradual gains.

Methods

This ARIES (ClinicalTrials.gov Identifier: NCT02581891) post hoc analysis describes outcomes in patients with treatment-naïve nAMD receiving treat-and-extend intravitreal aflibercept (IVT-AFL) for 104 weeks, who were identified as meeting criteria for an early hypothetical switch. Patients were categorized retrospectively according to six criteria (presence of central intraretinal and/or subretinal fluid at week 8 or 24, with/without a next planned treatment interval ≤ 8 weeks, and with/without gains in best-corrected visual acuity [BCVA] ≤ 5 letters [with absolute BCVA < 70 letters]).

Results

Hypothetical switch criteria were largely met due to the presence of central subretinal fluid rather than intraretinal fluid. Depending on the criterion, 8–46% of patients were considered to be hypothetical switchers. BCVA outcomes were not worse in the hypothetical switchers, irrespective of criteria. Using criteria of intraretinal/subretinal fluid at week 24 and a next planned treatment interval ≤ 8 weeks, mean changes in BCVA (letters) from baseline in hypothetical switchers and non-switchers were: + 6.1 (95% confidence interval [CI] 3.4, 8.8) and + 6.6 (95% CI 4.7, 8.6), respectively, at week 24; + 8.2 (95% CI 5.0, 11.3) and + 7.5 (95% CI 5.3, 9.7), respectively, at week 52; and + 5.7 (95% CI 1.3, 10.1) and + 3.4 (95% CI 0.1, 6.7), respectively, at week 104.

Conclusions

In newly diagnosed nAMD, there appears little rationale for early switching from IVT-AFL since, with continuous proactive treatment, comparable visual gains can be achieved by patients meeting hypothetical switch criteria compared with those who initially respond well on a treat-and-extend regimen. However, further prospective studies are needed.

Trial registration

ClinicalTrials.gov Identifier: NCT02581891.

Video Summary