Aflibercept in age-related macular degeneration: evaluating its role as a primary therapeutic option

Trends in Anti-Vascular Endothelial Growth Factor Original Medicare Part B Claims in the United States, 2014-2019

PURPOSE

To characterize trends in use of and expenditure for the intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents aflibercept, ranibizumab, and bevacizumab among the population enrolled in Original Medicare from 2014 to 2019.

METHODS

The Centers for Medicare and Medicaid Services Physician and Other Supplier Public Use File was used to extract Medicare Part B fee-for-service outpatient injection claims data submitted by ophthalmologists. Multivariable linear regression models were used to evaluate the association between reimbursement, ophthalmologist availability, and agent administration rate.

RESULTS

Between 2014 and 2019, 17,588,995 intravitreal injection claims were filed by 4218 US ophthalmologists. Medicare costs for anti-VEGF injections increased from 2.51 B USD in 2014 to 4.02 B USD in 2019. Increased state-level ophthalmologist availability and incremental increases in average reimbursement amounts were found to be significantly associated with a 6.8-fold variation in 2019 overall anti-VEGF injection rates across states.

CONCLUSIONS

Medicare injection rates and costs for anti-VEGF injections have both increased between 2014 and 2019, largely driven by increased aflibercept use. There is a significant association between ophthalmologist availability and anti-VEGF injection rate on the state level, suggesting access to care may contribute to the observed state-level disparities in intravitreal injection rates. Further characterization of factors contributing to the state-level variation in injection rates of individual anti-VEGF agents may help inform interventions promoting equitable access to and use of these drugs.

Polyurea-urethane Temperature-responsive Hydrogels for Sustained Delivery of Anti-VEGF Therapeutics

Temperature-responsive hydrogels, or thermogels, have emerged as a leading platform for sustained delivery of both small molecule drugs and macromolecular biologic therapeutics. Although thermogel properties can be modulated by varying the polymer's hydrophilic-hydrophobic balance, molecular weight and degree of branching, varying the supramolecular donor-acceptor interactions on the polymer remains surprisingly overlooked. Herein, to study the influence of enhanced hydrogen bonding on thermogelation, we synthesized a family of amphiphilic polymers containing urea and urethane linkages using quinuclidine as an organocatalyst. Our findings showed that the presence of strongly hydrogen bonding urea linkages significantly enhanced polymer hydration in water, in turn affecting hierarchical polymer self-assembly and macroscopic gel properties such as sol-gel phase transition temperature and gel stiffness. Additionally, analysis of the sustained release profiles of Aflibercept, an FDA-approved protein biologic for anti-angiogenic treatment, showed that urea bonds on the thermogel were able to significantly alter the drug release mechanism and kinetics compared to usage of polyurethane gels of similar composition and molecular weight. Our findings demonstrate the unrealized possibility of modulating gel properties and outcomes of sustained drug delivery through judicious variation of hydrogen bonding motifs on the polymer structure.

Evaluating the Efficacy and Safety of Aflibercept Biosimilar (P041) Compared with Originator Product in Patients with Neovascular Age-Related Macular Degeneration

OBJECTIVE

To assess the noninferiority of biosimilar aflibercept (P041, CinnaGen) to the originator aflibercept (AFL, Regeneron) in terms of efficacy, safety, and immunogenicity.

DESIGN

This was a phase Ш, 52-week, multicenter, randomized, double-masked, and active control trial involving eyes in a 1:1 ratio.

SUBJECTS

Patients with active subfoveal choroidal neovascularization secondary to age-related macular degeneration randomized into the 2 groups of P041 and AFL.

METHODS

Patients received an injection of aflibercept every 4 weeks for 3 doses, followed by administration every 8 weeks up to week 48.

MAIN OUTCOME MEASURES

The primary outcome was the noninferiority analysis of eyes maintaining vision at week 52. Secondary outcomes included the changes in visual acuity and retinal thickness, safety evaluation, and immunogenicity during the study.

RESULTS

In total, 168 eyes of 168 patients were included. At week 52, the proportion of patients maintaining vision was 94.44% in the P041 group compared with 94.52% in the AFL group. The 95% confidence interval (CI) for the difference of maintaining vision from baseline did not exceed the predefined noninferiority margin of 10% (difference, -0.0008; 95% CI, -0.074 to 0.074; P = 0.98). Secondary outcomes indicated similar results in both arms (all P > 0.05). Safety measured outcomes and immunogenicity were similar between the 2 study groups.

CONCLUSIONS

Biosimilar aflibercept was noninferior to AFL in eyes with neovascular age-related macular degeneration. Other efficacy and safety findings also indicated the similarity of 2 products.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Transitioning from Aflibercept to Biosimilar Ranibizumab in Neovascular AMD (The TRANSFORM Trial): A Multicenter Observational Study

Purpose

This study investigates the efficacy of transitioning patients with neovascular age-related macular degeneration (nAMD) from aflibercept (T1) to biosimilar ranibizumab (T2), an approach not previously documented in literature.

Methods

In this multicenter observational study, patients over 50 years of age with nAMD were shifted from intravitreal aflibercept (IVI AFL) to biosimilar ranibizumab (B-RBZ) due to financial constraints. This study employed standardized ophthalmological methods to assess visual acuity (VA), central macular thickness (CMT), and subretinal and intraretinal fluid. Statistical analyses included paired t-tests, Wilcoxon signed-rank tests, and linear regression.

Results

A total of 29 eyes (12 males and 17 females) were analyzed. Mean age was 72.55 ±6.43 years. VA improved significantly during T1, with a mean increase from 55.0 ± 10.2 to 70.0 ± 8.5 ETDRS letters at the switch time point (p < 0.01), then a slight decrease to 62.3 ± 8.9 at 12 months (p < 0.05) was noted during T2. The mean CMT decreased notably from 400 ± 50 to 290 ± 45 μm at the switch. The final CMT at 12 months after switching to B-RBZ was 280 ± 40 μm (p < 0.01). There was a significant decrease in the retinal and intra retinal fluid during T1, followed by a gradual increase during T2. A significant correlation (p < 0.05) was noted between the presence of intraretinal fluid and increased injection frequency of B-RBZ.

Conclusion

The switch from IVI AFL to IVI B-RBZ in patients with nAMD demonstrated efficacy in maintaining the VA and macular anatomy, with some challenges in fluid management.

Short-Term Outcomes of Faricimab in Patients with Neovascular Age-Related Macular Degeneration on Prior Anti-VEGF Therapy

PURPOSE

A subset of patients with neovascular age-related macular degeneration (nAMD) experience treatment burden and suboptimal response with anti-VEGF therapy. The aim of this study was to investigate the effect of switching to a novel, bispecific agent, faricimab, in patients with nAMD currently treated with anti-VEGF.

DESIGN

Retrospective, noncomparative cohort study.

SUBJECTS

Patients with nAMD previously treated with anti-VEGF and switched to intravitreal faricimab injection (IFI) at the Cleveland Clinic's Cole Eye Institute.

METHODS

Switching and administration schedule of IFI was at the discretion of the clinician. Visual acuity (VA) and macular OCT parameters, including central subfield thickness (CST), maximum pigment epithelial detachment (PED) height, and presence of subretinal (SRF) or intraretinal fluid (IRF), were assessed at baseline (day of first IFI) and after each IFI.

MAIN OUTCOME MEASURES

Central subfield thickness and presence of IRF or SRF after ≥ 3 IFIs.

RESULTS

One hundred twenty-six eyes of 106 patients were included in the analysis with a mean follow-up time of 24.3 ± 5.2 weeks. Before switching to IFI, patients received a mean of either aflibercept (20.0 ± 8.4, mean ± standard deviation), bevacizumab (7 ± 8.9), ranibizumab (1.9 ± 8.5), or brolucizumab (0.3 ± 1.6) injections. The most common agent used before switching to IFI was aflibercept (n = 110, 87%), and the mean treatment interval with any anti-VEGF was 5.6 ± 1.6 weeks before switching. Central subfield thickness was reduced from baseline after the first IFI (266.8 ± 64.7 vs. 249.8 ± 58.6 μm, P = 0.02) and persisted over the 3 IFIs (P = 0.01). Pigment epithelial detachment height was reduced after the third IFI (249.6 ± 179.0 vs. 206.9 ± 130.0 μm, P = 0.01). The mean VA (62.9 vs. 62.7 approximate ETDRS letters, P = 0.42) and interval between injections (6.3 vs. 5.7 weeks, P = 0.16) was similar after the third IFI compared with baseline. Eleven (8.7%) eyes were switched back to their previous anti-VEGF, including 2 (1.6%) eyes from 1 patient with intraocular inflammation requiring cessation of IFI. There were no other adverse events from switching.

CONCLUSIONS

Switching to faricimab resulted in a reduction in mean CST (-11.6 μm, P = 0.01) and PED height (-44.2 μm, P = 0.01) after 3 injections, with stable VA and at a similar treatment interval to prior anti-VEGF therapy.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Stages, pathogenesis, clinical management and advancements in therapies of age-related macular degeneration

Age-related macular degeneration (AMD) is a retinal degenerative disorder prevalent in the elderly population, which leads to the loss of central vision. The disease progression can be managed, if not prevented, either by blocking neovascularization ("wet" form of AMD) or by preserving retinal pigment epithelium and photoreceptor cells ("dry" form of AMD). Although current therapeutic modalities are moderately successful in delaying the progression and management of the disease, advances over the past years in regenerative medicine using iPSC, embryonic stem cells, advanced materials (including nanomaterials) and organ bio-printing show great prospects in restoring vision and efficient management of either forms of AMD. This review focuses on the molecular mechanism of the disease, model systems (both cellular and animal) used in studying AMD, the list of various regenerative therapies and the current treatments available. The article also highlights on the recent clinical trials using regenerative therapies and management of the disease.

Construction of a ferroptosis-associated circRNA-miRNA-mRNA network in age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of severe vision impairment in the aging population. However, the underlying molecular mechanism remains unclear. Ferroptosis is a novel non-apoptotic programmed cell death pathway, that contributes to AMD. In addition, non-coding RNA-led epigenetic profile was identified in the regulation of AMD progression. Considering that non-coding RNAs are vital regulators of ferroptosis-related genes in various pathological events, we explored and constructed a ferroptosis-associated circRNA-miRNA-mRNA network in AMD. Differential expression of fourteen ferroptosis-associated genes were identified based on our microarray analysis and the FerrDb tool at the threshold of P < 0.05 and log₂|fold change| ≥ 1, which were subsequently validated by the public datasets. We further screened eight miRNAs via public datasets and the miRNet database. Based on these eight miRNAs, 23 circRNAs were mined using the Starbase tool. Taking all these together, we obtained a ferroptosis-related network with 414 pairs of circRNA-miRNA-mRNA, which are potential targets in future AMD treatments.

Recent Advances in Age-Related Macular Degeneration Therapies

Age-related macular degeneration (AMD) was described for the first time in the 1840s and is currently the leading cause of blindness for patients over 65 years in Western Countries. This disease impacts the eye’s posterior segment and damages the macula, a retina section with high levels of photoreceptor cells and responsible for the central vision. Advanced AMD stages are divided into the atrophic (dry) form and the exudative (wet) form. Atrophic AMD consists in the progressive atrophy of the retinal pigment epithelium (RPE) and the outer retinal layers, while the exudative form results in the anarchic invasion by choroidal neo-vessels of RPE and the retina. This invasion is responsible for fluid accumulation in the intra/sub-retinal spaces and for a progressive dysfunction of the photoreceptor cells. To date, the few existing anti-AMD therapies may only delay or suspend its progression, without providing cure to patients. However, in the last decade, an outstanding number of research programs targeting its different aspects have been initiated by academics and industrials. This review aims to bring together the most recent advances and insights into the mechanisms underlying AMD pathogenicity and disease evolution, and to highlight the current hypotheses towards the development of new treatments, i.e., symptomatic vs. curative. The therapeutic options and drugs proposed to tackle these mechanisms are analyzed and critically compared. A particular emphasis has been given to the therapeutic agents currently tested in clinical trials, whose results have been carefully collected and discussed whenever possible.

Shaping the Microglia in Retinal Degenerative Diseases Using Stem Cell Therapy: Practice and Prospects

Retinal degenerative disease (RDD) refers to a group of diseases with retinal degeneration that cause vision loss and affect people's daily lives. Various therapies have been proposed, among which stem cell therapy (SCT) holds great promise for the treatment of RDDs. Microglia are immune cells in the retina that have two activation phenotypes, namely, pro-inflammatory M1 and anti-inflammatory M2 phenotypes. These cells play an important role in the pathological progression of RDDs, especially in terms of retinal inflammation. Recent studies have extensively investigated the therapeutic potential of stem cell therapy in treating RDDs, including the immunomodulatory effects targeting microglia. In this review, we substantially summarized the characteristics of RDDs and microglia, discussed the microglial changes and phenotypic transformation of M1 microglia to M2 microglia after SCT, and proposed future directions for SCT in treating RDDs.

Epithelial-mesenchymal transition-related serum markers ET-1, IL-8 and TGF-β2 are elevated in a Finnish wet age-related macular degeneration cohort

PURPOSE

It has been hypothesized that epithelial-mesenchymal transition (EMT) may occur in the retinal pigment epithelium of advanced stage age-related macular degeneration (AMD). Various serum and plasma growth factors and inflammatory mediators have been linked to AMD. We were interested in finding out whether systemic levels of EMT-associated markers were altered in the serum of wet AMD patients. Serum biomarkers associated with the various pathological processes of AMD may present an avenue towards identifying and characterizing the birth mechanisms of wet AMD, its progression and severity, paving the way towards the application of precision medicine.

METHODS

We chose to measure the serum levels of known biomarkers of EMT - EGF (epidermal growth factor), ET-1 (endothelin 1), IL-8 (interleukin 8), TGF-β1 and TGF-β2 (transforming growth factor-beta 1 and 2) and VEGF-A (vascular endothelial growth factor A) - using enzyme-linked immunosorbent assays. We measured them from 71 Finnish wet AMD patients who were receiving intravitreal anti-VEGF-A injection treatments, as well as 64 age-adjusted controls.

RESULTS

We found significantly elevated levels of ET-1, IL-8 and TGF-β2 in the serums of wet AMD patients.

CONCLUSIONS

ET-1, IL-8 and TGF-β2 appear to be useful serum biomarkers in understanding active wet AMD. However, we cannot conclude that local retinal EMT-processes could be observed from the corresponding systemic serum biomarkers in patients undergoing anti-VEGF-A treatments.

A proof of concept study to evaluate the treatment response of aflibercept in wARMD using OCT-A (Canada study)

PURPOSE

To Utilize OCT-A to measure the change in size (mm²) and density (flow index) of choroidal neovascular membranes (CNVMs) from baseline to week 52 of treatment-naïve wet age-related macular degeneration (wARMD) patients receiving intravitreal aflibercept injections (IAI).

METHODS

Patients were treated with IAI at baseline, month 1 and month 2 and then every other month for a total of 12 months. Along with clinical examination and best corrected visual acuity (BCVA), OCT-A 6- and 3-mm scans were acquired at every visit between May 2017 and January 2019. Data from baseline, week 12 and week 52 were analyzed prospectively and included in the final analysis.

RESULTS

Twenty-five eyes from 23 patients were included in the study. The mean BCVA at baseline and week 52 increased from 20/125 to 20/80, respectively (p < 0.001). The mean CST at baseline and week 52 decreased from 330.48 to 222.40 μm, respectively (p < 0.001). 1Seventeen patients (18 eyes) completed all protocol-based 6 × 6 mm and 3 × 3 mm OCT-A scans. In this subgroup, 6-mm OCT-A scans revealed that the mean size of the CNVM before and after IAI was 1.21 mm² and 0.56 mm², respectively (p < 0.001), while the 3-mm OCT-A scans at baseline and week 52 demonstrated a decrease in mean size of the CNVM from 0.89 to 0.37 mm², respectively (p < 0.001). The 6-mm perfusion density map revealed no difference at either time points.

CONCLUSIONS

OCT-A provides a useful approach for monitoring and evaluating the treatment of intravitreal aflibercept for CNVMs. Mean size of CNVMs can be identified by 3- or 6-mm scans, but without machine learning, it requires extensive segmentation. While reproducibility and clear delineation of CNVMs in wARMD using OCT-A is challenging, OCT-A does offer the ability to monitor CNVM size changes during treatment and may offer another biomarker to assist in assessing treatment response.

mTORC1 and mTORC2 are differentially engaged in the development of laser-induced CNV

Background

The mechanistic target of rapamycin (mTOR) pathway is a potential target to inhibit pathologic processes in choroidal neovascularization. However, the exact role of mTOR signaling in the development of CNV remains obscure. In this study, we assessed the role of mTORC1 and mTORC2 as well as the effect of rapamycin (sirolimus) on choroidal neovascularization (CNV) in a laser-induced mouse model.

Methods

In experiment A, we observed the natural course of CNV development and the dynamics of mTOR-related proteins during the 12 days after the laser injury. The expression of mTOR-related proteins was evaluated using Western blot (WB). Cryosections of CNV-induced mice were immunostained for the visualization of the vascular and extravascular components of the CNV. Experiment B was performed to confirm the critical period of mTOR signaling in the development of laser-induced CNV, we administered rapamycin before and/or during the active period of mTOR complexes. WB and immunofluorescence staining was performed to evaluate the mode of action and the effect of mTOR inhibition on CNV development.

Results

In experiment A, we detected high levels of p-mTOR S2448 and p-mTOR S2481 from the 5th to 12th day of laser injury. Immunofluorescence imaging of cryosections of mice sacrificed on day 7 revealed greater co-immunoreactivity of p-mTOR S2448 positive cells with CD11b and F4/80, while p-mTOR S2481 positive cells showed colocalization with CD31, α-SMA, and cytokeratin. In experiment B, rapamycin injection during the active period of mTOR signaling demonstrated near-complete inhibition of CNV lesion as well as significant induction of autophagy.

Conclusion

Our study suggests the mTOR as a critical player during CNV development in laser-induced mouse model through differentially acting with the mTORC1 and mTORC2. mTORC1 activity was high predominantly in inflammatory cells in CNV lesion, while mTORC2 activity was higher in vascular components and the RPE.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0380-0) contains supplementary material, which is available to authorized users.

The Placental Growth Factor Pathway and Its Potential Role in Macular Degenerative Disease

There is growing evidence that placental growth factor (PlGF) is an important player in multiple pathologies, including tumorigenesis, inflammatory disorders and degenerative retinopathies. PlGF is a member of the vascular endothelial growth factor (VEGF) family and in the retina, binding of this growth factor to specific receptors is associated with pathological angiogenesis, vascular leakage, neurodegeneration and inflammation. Although they share some receptor signalling pathways, many of the actions of PlGF are distinct from VEGF and this has revealed the enticing prospect that it could be a useful therapeutic target for treating early and late stages of diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Recent research suggests that modulation of PlGF could also be important in the geographic atrophy (GA) form of late AMD by protecting the outer retina and the retinal pigment epithelium (RPE). This review discusses PlGF and its signalling pathways and highlights the potential of blocking the bioactivity of this growth factor to treat irreversible visual loss due to the two main forms of AMD.

Aflibercept: A review of its effect on the treatment of exudative age-related macular degeneration

Considerable improvement has been achieved in the way in which exudative age-related macular degeneration is conventionally treated and in the associated visual outcomes and prognosis, thanks to the agents with effects against vascular endothelial growth factor (anti-VEGF). By comparison to earlier treatment approaches that involved the use of lasers, the anti-VEGF agents have made it possible to accomplish more positive visual and anatomical outcomes in cases of exudative age-related macular degeneration. Indeed, owing to their positive effects, anti-VEGF agents have quickly come to be considered the gold standard for the treatment of wet age-related macular degeneration. Aflibercept, the most recently approved intravitreally administered anti-VEGF, seems to mark another milestone in the treatment of wet age-related macular degeneration. This anti-VEGF agent presents a series of singular pharmacodynamic and pharmacokinetic attributes that provide it a number of biological benefits in relation to the treatment of choroidal neovascularization compared to other agents. These attributes include high level of affinity for the VEGF-A factor, an intravitreal half-life of great length, as well as the ability to serve as an antagonist for other growth factors besides VEGF. The impact of Aflibercept on the manner in which exudative age-related macular degeneration is managed was demonstrated by thoroughly reviewing the related literature. The present review article highlights the pharmacology, pharmacokinetics, safety and effectiveness of this anti-VEGF agent as well as the landmark clinical studies that have been carried out to establish this drug as a gold standard in the therapy of neovascular age-related macular degeneration. In addition, studies regarding the outcomes and effectiveness of the various dosage regimens, either as monotherapy or in combination with other agents, are also reviewed.

Preclinical Evaluation of ADVM-022, a Novel Gene Therapy Approach to Treating Wet Age-Related Macular Degeneration

Inhibition of vascular endothelial growth factor, a key contributor to the choroidal neovascularization associated with wet age-related macular degeneration, is the mode of action of several approved therapies, including aflibercept, which requires frequent intravitreal injections to provide clinical benefit. Lack of compliance with the dosing schedule may result in recurrence of active wet macular degeneration, leading to irreversible vision impairment. Gene therapy providing sustained anti-vascular endothelial growth factor levels in the retina following a single injection could drastically reduce the treatment burden and improve visual outcomes. ADVM-022, an adeno-associated virus vector encoding aflibercept, is optimized for intravitreal delivery and strong protein expression. Here, we report the long-term expression and efficacy of ADVM-022-derived aflibercept in a laser-induced choroidal neovascularization model in non-human primates. Intravitreal administration of ADVM-022 was well tolerated and resulted in sustained aflibercept levels. In addition, ADVM-022 administration 13 months before lasering prevented the occurrence of clinically relevant choroidal neovascularization lesions, similar to animals that received a bolus of intravitreal aflibercept (standard of care) at the time of lesioning. These results demonstrate that a single intravitreal administration of ADVM-022 may provide a safe and effective long-term treatment option for wet macular degeneration and may ultimately improve patients’ visual outcomes.

Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD

Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.

A Review of Anti-Angiogenic Targets for Monoclonal Antibody Cancer Therapy

Tumor angiogenesis is a key event that governs tumor progression and metastasis. It is controlled by the complicated and coordinated actions of pro-angiogenic factors and their receptors that become upregulated during tumorigenesis. Over the past several decades, vascular endothelial growth factor (VEGF) signaling has been identified as a central axis in tumor angiogenesis. The remarkable advent of recombinant antibody technology has led to the development of bevacizumab, a humanized antibody that targets VEGF and is a leading clinical therapy to suppress tumor angiogenesis. However, despite the clinical efficacy of bevacizumab, its significant side effects and drug resistance have raised concerns necessitating the identification of novel drug targets and development of novel therapeutics to combat tumor angiogenesis. This review will highlight the role and relevance of VEGF and other potential therapeutic targets and their receptors in angiogenesis. Simultaneously, we will also cover the current status of monoclonal antibodies being developed to target these candidates for cancer therapy.