Long-term outcomes of switching to aflibercept for treatment-resistant neovascular age-related macular degeneration

Treatment Strategies for Anti-VEGF Resistance in Neovascular Age-Related Macular Degeneration by Targeting Arteriolar Choroidal Neovascularization

Despite extensive use of intravitreal anti-vascular endothelial growth factor (anti-VEGF) biologics for over a decade, neovascular age-related macular degeneration (nAMD) or choroidal neovascularization (CNV) continues to be a major cause of irreversible vision loss in developed countries. Many nAMD patients demonstrate persistent disease activity or experience declining responses over time despite anti-VEGF treatment. The underlying mechanisms of anti-VEGF resistance are poorly understood, and no effective treatment strategies are available to date. Here we review evidence from animal models and clinical studies that supports the roles of neovascular remodeling and arteriolar CNV formation in anti-VEGF resistance. Cholesterol dysregulation, inflammation, and ensuing macrophage activation are critically involved in arteriolar CNV formation and anti-VEGF resistance. Combination therapy by neutralizing VEGF and enhancing cholesterol removal from macrophages is a promising strategy to combat anti-VEGF resistance in CNV.

Long term results of patients with neovascular age-related macular degeneration switched from other anti-VEGF agents to intravitreal Aflibercept

Background

This study explores the long term anatomic and functional results of patients who were switched to intravitreal aflibercept injections (IAI) after being initially managed with other anti-VEGF agents for neovascular age-related macular degeneration (nAMD).

Methods

Patients with nAMD were included if they started with another anti-VEGF agent and were switched to IAI. Subjects had at least 3 years of consistent therapy with IAI and at least 1 injection quarterly.

Results

Eighty-eight patients had at least 3 years of treatment while 58 of those patients, had at least 4 years of IAI. Average treatment time with other anti-VEGF agents was 32 months prior to switching. Baseline best corrected vision (VA) was 59.4 letters (20/70 + 2). At time of switch, VA increased significantly to 66.7 letters (20/50 + 2). At 3 months after switch, VA increased significantly to 69.0 (20/40−) letters. After 3 years of consistent IAI, vision was 67.5 letters (20/40−2), and for those patients that completed 4 years of therapy, the average VA was 66.0 letters (20/50 + 2), with a gain of 6.6 letters over baseline vision. 32.1% of patients gained 3 or more lines of vision. Initial central macular thickness (CMT) was 369 µm, which improved to 347 µm at time of switch, and further improved at 3 months to 301 µm and was maintained over time.

Conclusion

Patients switched to IAI can maintain vision over the long term. Patients treated on average for 5.7 years, had a visual gain of 8.1 letters after 3 years and 6.6 letters after 4 years of IAI therapy. CMT significantly improved following the switch and was maintained.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40942-022-00361-9.

Radiation retinopathy intricacies and advances in management

Background: Radiation retinopathy is a chronic, progressive, vision-threatening complication from exposure to various radiation sources. While several treatment modalities are available, proper management for this disease is a continuing challenge with no consensus on the most efficacious.Objective: The aim of this article is to provide an updated review of the published literature on the course of the disease, available treatments and their efficacies, frequency of regimen, core issues in patient management, and additional newer treatment modalities, including possible prophylactic approaches.Value: We also highlighted the challenges encountered with managing chronically treated patients through an analysis of a clinical case report on a patient who was treated for several years with different modalities after a diagnosis of radiation retinopathy.

Anti-VEGF-Resistant Retinal Diseases: A Review of the Latest Treatment Options

Anti-vascular endothelial growth factor (anti-VEGF) therapy currently plays a central role in the treatment of numerous retinal diseases, most notably exudative age-related macular degeneration (eAMD), diabetic retinopathy and retinal vein occlusions. While offering significant functional and anatomic benefits in most patients, there exists a subset of 15–40% of eyes that fail to respond or only partially respond. For these cases, various treatment options have been explored with a range of outcomes. These options include steroid injections, laser treatment (both thermal therapy for retinal vascular diseases and photodynamic therapy for eAMD), abbreviated anti-VEGF treatment intervals, switching anti-VEGF agents and topical medications. In this article, we review the effectiveness of these treatment options along with a discussion of the current research into future directions for anti-VEGF-resistant eyes.

Safety and Biocompatibility of Aflibercept-Loaded Microsphere Thermo-Responsive Hydrogel Drug Delivery System in a Nonhuman Primate Model

Purpose

To evaluate the safety and tolerability of a microsphere thermo-responsive hydrogel drug delivery system (DDS) loaded with aflibercept in a nonhuman primate model.

Methods

A sterile 50 µL of aflibercept-loaded microsphere thermo-responsive hydrogel-DDS (aflibercept-DDS) was injected intravitreally into the right eye of 10 healthy rhesus macaques. A complete ophthalmic examination, intraocular pressure (IOP) measurement, fundus photography, spectral-domain optical coherence tomography (SD-OCT), and electroretinogram were performed monthly for 6 months. One macaque was euthanized monthly, and the enucleated eyes were submitted for measurement of bioactive aflibercept concentrations. Four eyes were submitted for histopathology.

Results

Injected aflibercept-DDS was visualized in the vitreous until 6 months postinjection. No abnormalities were observed in the anterior segment, and IOP remained within normal range during the study period. A small number of cells were observed in the vitreous of some macaques, but otherwise the remainder of the posterior segment examination was normal. No significant changes in retinal architecture or function as assessed by SD-OCT and histology or full-field electroretinography, respectively, were observed. A mild, focal foreign body reaction around the injectate was observed with histology at 6 months postinjection. A mean of 2.1 ng/µL of aflibercept was measured in the vitreous.

Conclusions

Intravitreally injected aflibercept-DDS achieved controlled, sustained release of aflibercept with no adverse effects for up to 6 months in the eyes of healthy rhesus macaques.

Translational Relevance

Aflibercept-DDS may be a more effective method to deliver bioactive antivascular endothelial growth factor agents than current practice by reducing the frequency of intravitreal injections and providing controlled drug release.

Prospective Study of Vessel Density by Optical Coherence Tomography Angiography After Intravitreal Bevacizumab in Exudative Age-Related Macular Degeneration

INTRODUCTION

The aim of this study was to evaluate retinal and choriocapillaris (CC) vessel density, using optical coherence tomography angiography (OCTA), in the macular region at baseline and after three once-monthly intravitreal injections of bevacizumab (loading phase) in patients affected by exudative age-related macular degeneration (AMD).

METHODS

A total 38 eyes of 38 patients with exudative AMD (16 women, 22 men; mean age 72.47 ± 7.46 years) were included in this study. We evaluated vessel density in different macular areas (whole image, fovea and parafovea) of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC. In addition, central macular thickness (CMT) and choroidal thickness in the foveal region and 500 µm in the nasal and temporal directions were analyzed by enhanced depth image-OCT.

RESULTS

There were no significant differences in vessel density in the SCP, DCP and CC after the loading phase compared to baseline (p > 0.05). In contrast, CMT (p = 0.039; 320.63 ± 175.05 vs. 372.47 ± 167.05 µm) and subfoveal choroidal thickness (SFCT) (p < 0.001; 189.21 ± 37.66 µm vs 170.37 ± 37.96 µm) significantly decreased after the loading phase compared to baseline. No significant correlations were found between SFCT and CC vessel density in the fovea, and between CMT and SCP and DCP (p > 0.05) at baseline and after the loading phase. Also, best corrected visual acuity did not correlate with CMT, SCP and DCP at baseline and after treatment (p > 0.05).

CONCLUSION

Macular and choroidal thickness did not correlate with vessel density, but probably correlated to vascular exudation. The anti-VEGF treatment, acting on vascular hyperpermeability, determines the reduction of the retinal and choroidal exudation, resulting in a decrease of their thicknesses. Consequently, these parameters could reflect the effectiveness of the anti-VEGF injections for treating exudative AMD respect to OCTA parameters.

TRIAL REGISTRATION

ClinicalTrials.gov indentifier, NTC04138420.