Aflibercept in wet AMD: specific role and optimal use

Intravitreal aflibercept 8 mg in neovascular age-related macular degeneration (PULSAR): 48-week results from a randomised, double-masked, non-inferiority, phase 3 trial

BACKGROUND

Intravitreal aflibercept 8 mg could improve treatment outcomes and provide sustained disease control in patients with neovascular age-related macular degeneration (nAMD), with extended dosing compared with aflibercept 2 mg.

METHODS

PULSAR is a phase 3, randomised, three-group, double-masked, non-inferiority, 96-week trial conducted across 223 sites worldwide. Adults with nAMD were randomised 1:1:1 to aflibercept 8 mg every 12 weeks (8q12), aflibercept 8 mg every 16 weeks (8q16), or aflibercept 2 mg every 8 weeks (2q8), following three initial monthly doses in all groups. From week 16, patients in the aflibercept 8 mg groups had their dosing interval shortened if pre-specified dose regimen modification criteria denoting disease activity were met. The primary endpoint was change from baseline in best-corrected visual acuity (BCVA) at week 48. All patients with at least one dose of study treatment were included in the efficacy and safety analyses. This trial is registered with ClinicalTrials.gov (NCT04423718) and is ongoing.

FINDINGS

Of 1011 patients randomised to aflibercept 8q12 (n=336), 8q16 (n=338), or 2q8 (n=337) between Aug 11, 2020, and July 30, 2021, 1009 patients received study treatment (aflibercept 8q12 n=335; aflibercept 8q16 n=338; and aflibercept 2q8 n=336). Aflibercept 8q12 and 8q16 showed non-inferior BCVA gains versus aflibercept 2q8 (mean BCVA change from baseline +6·7 [SD 12·6] and +6·2 [11·7] vs +7·6 [12·2] letters). The least squares mean differences between aflibercept 8q12 versus 2q8 and 8q16 versus 2q8, respectively, were -0·97 (95% CI -2·87 to 0·92) and -1·14 (-2·97 to 0·69) letters (non-inferiority margin at 4 letters). The incidence of ocular adverse events in the study eye was similar across groups (aflibercept 8q12 n=129 [39%]; aflibercept 8q16 n=127 [38%]; and aflibercept 2q8 n=130 [39%]).

INTERPRETATION

Aflibercept 8 mg showed efficacy and safety with extended dosing intervals, which has the potential to improve the management of patients with nAMD.

FUNDING

Bayer AG and Regeneron Pharmaceuticals.

Lentiviral delivered aflibercept OXB-203 for treatment of neovascular AMD

Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness in the aging population, with vascular endothelial growth factor (VEGF) playing a key role. Treatment with recombinant anti-VEGFs is the current standard of care; however, it is only effective for 1-2 months at a time and requires re-administration. Gene therapy could pave the way for stable, long-term expression of therapeutic anti-VEGF with a single dose, reducing the frequency of treatment and potentially improving clinical outcomes. As such, we have developed OXB-203, a lentiviral-based gene therapy encoding the anti-VEGF protein aflibercept. Aflibercept derived from OXB-203 exhibited comparable in vitro binding characteristics to VEGF as recombinant aflibercept. Furthermore, its biological potency was demonstrated by the equivalent inhibition of VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and tubule formation as recombinant aflibercept. In a rat choroidal neovascularization (CNV) model of nAMD, a single subretinal administration of OXB-203 reduced laser-induced CNV lesion areas analogous to an intravitreal bolus of recombinant aflibercept. Finally, in a head-to-head comparative study, aflibercept derived from OXB-203 was shown to be expressed at significantly higher levels in ocular tissues than from an AAV8-aflibercept vector following a single subretinal delivery to rats. These findings support the therapeutic potential of OXB-203 for the management of nAMD.

LC/MS Assessment of Glycoform Clearance of A Biotherapeutic MAb in Rabbit Ocular Tissues

Many biotherapeutics such as monoclonal antibodies (mAbs) consist of various glycoforms, which can have different PK properties upon administration to animals and human. As a result, it is necessary to monitor the abundance of glycoforms and limit lot-to-lot variability during the manufacturing process. However, limited information is known about the clearance of mAb glycoforms from ocular space upon intravitreal injection. We present here an assessment of glycoform clearance of a biotherapeutic mAb (IgG1) from rabbit vitreous humor, aqueous humor and retina tissue using LC/MS. The results show that G0, G0F and G1F have similar T1/2, while mannose-5 has a longer T1/2 and is cleared slower in rabbit ocular space, which contradicted with what has been reported in the literature in which Mann5 was cleared faster systematically.

Vascular Endothelial Growth Factor Receptor 1 Targeting Fusion Polypeptides with Stimuli-Responsiveness for Anti-angiogenesis

Genetically engineered fusion polypeptides have been investigated to introduce unique bio-functionality and improve some therapeutic activity for anti-angiogenesis. We report herein that stimuli-responsive, vascular endothelial growth factor receptor 1 (VEGFR1) targeting fusion polypeptides composed of a VEGFR1 (fms-like tyrosine kinase-1 (Flt1)) antagonist, an anti-Flt1 peptide, and a thermally responsive elastin-based polypeptide (EBP) were rationally designed at the genetic level, biosynthesized, and purified by inverse transition cycling to develop potential anti-angiogenic fusion polypeptides to treat neovascular diseases. A series of hydrophilic EBPs with different block lengths were fused with an anti-Flt1 peptide, forming anti-Flt1-EBPs, and the effect of EBP block length on their physicochemical properties was examined. While the anti-Flt1 peptide decreased phase-transition temperatures of anti-Flt1-EBPs, compared with EBP blocks, anti-Flt1-EBPs were soluble under physiological conditions. The anti-Flt1-EBPs dose dependently inhibited the binding of VEGFR1 against vascular endothelial growth factor (VEGF) as well as tube-like network formation of human umbilical vein endothelial cells under VEGF-triggered angiogenesis in vitro because of the specific binding between anti-Flt1-EBPs and VEGFR1. Furthermore, the anti-Flt1-EBPs suppressed laser-induced choroidal neovascularization in a wet age-related macular degeneration mouse model in vivo. Our results indicate that anti-Flt1-EBPs as VEGFR1-targeting fusion polypeptides have great potential for efficacious anti-angiogenesis to treat retinal-, corneal-, and choroidal neovascularization.

Seven-year outcomes following intensive anti-vascular endothelial growth factor therapy in patients with exudative age-related macular degeneration

BACKGROUND

Anti-vascular endothelial growth factor (VEGF) therapy is currently the most effective therapy of exudative age-related macular degeneration (AMD). The aim of this study was to assess long-term benefits of intensive aflibercept and ranibizumab anti-VEGF therapy in patients with exudative AMD.

METHODS

Two clinical trial sites recruited their original subjects for a re-evaluation 7 years after the baseline visit of the phase-3 Vascular Endothelial Growth Factor (VEGF) Trap-Eye: Investigation of Efficacy and Safety in Wet Age-Related Macular Degeneration (VIEW 2) trial. Forty-seven eyes of 47 patients with AMD originally treated with ranibizumab (14 eyes) or aflibercept (33 eyes) were included.

RESULTS

Mean number of injections was 17.8 ± 3.0 during participation in the VIEW 2 trial. Fourteen of 47 (30%) eyes were given additional injections with a mean number of 5.7 ± 4.5 after the trial. At a mean follow-up time of 82 ± 5 months best corrected visual acuity (BCVA) remained stable or improved (≤ 10 letters lost) in 55% of patients in the entire study population, in 43% in the ranibizumab group and in 60% in the aflibercept group. In both groups combined mean BCVA was 54 ± 13 letters at baseline, 65 ± 17 letters at the end of the intensive phase and 45 ± 25 letters at the end of follow-up. There was no statistically significant difference in BCVA between the two groups at baseline (p = 0.88) and at the end of follow-up (p = 0.40). Macular atrophy was observed in 96% of eyes, average area was 7.22 ± 6.31 mm² with no statistically significant difference between groups (p = 0.47). Correlation between BCVA at end-of-follow-up and the area of atrophy was significant (p < 0.001). At the end of follow-up, fluid was detected in 7 of 47 eyes (15%) indicating disease activity.

CONCLUSION

Long-term efficacy of aflibercept and ranibizumab was largely consistent. Following a two-year intensive therapy with as-needed regimen, BCVA was maintained or improved in almost half of the patients and in the ranibizumab group and more than half of the patients in the aflibercept group with very few injections. In a remarkable proportion of eyes, BCVA declined severely which underlines the need for long-term follow-ups and may indicate a more prolonged intensive therapy.

TRIAL REGISTRATIONS

VIEW 2 study: ClinicalTrials.gov ID: NCT00637377, date of registration: March 18, 2008. Long-term follow-up: IRB nr.: SE RKEB 168/2022, ClinicalTrials.gov ID: NCT05678517, date of registration: December 28, 2022, retrospectively registered.

From mouse to human: Accessing the biochemistry of vision in vivo by two-photon excitation

The eye is an ideal organ for imaging by a multi-photon excitation approach, because ocular tissues such as the sclera, cornea, lens and neurosensory retina, are highly transparent to infrared (IR) light. The interface between the retina and the retinal pigment epithelium (RPE) is especially informative, because it reflects the health of the visual (retinoid) cycle and its changes in response to external stress, genetic manipulations, and drug treatments. Vitamin A-derived retinoids, like retinyl esters, are natural fluorophores that respond to multi-photon excitation with near IR light, bypassing the filter-like properties of the cornea, lens, and macular pigments. Also, during natural aging some retinoids form bisretinoids, like diretinoid-pyridiniumethanolamine (A2E), that are highly fluorescent. These bisretinoids appear to be elevated concurrently with aging. Vitamin A-derived retinoids and bisretinoidss are detected by two-photon ophthalmoscopy (2PO), using a new class of light sources with adjustable spatial, temporal, and spectral properties. Furthermore, the two-photon (2P) absorption of IR light by the visual pigments in rod and cone photoreceptors can initiate visual transduction by cis-trans isomerization of retinal, enabling parallel functional studies. Recently we overcame concerns about safety, data interpretation and complexity of the 2P-based instrumentation, the major roadblocks toward advancing this modality to the clinic. These imaging and retina-function assessment advancements have enabled us to conduct the first 2P studies with humans.

High-Dose Aflibercept for Neovascular AMD and DME in Suboptimal Responders to Standard-Dose Aflibercept

Purpose: To assess the effect of higher dose (HD) aflibercept on visual acuity (VA), optical coherence tomography outcomes, and injection burden in eyes with neovascular age-related macular degeneration (nAMD) or diabetic macular edema (DME) that responded suboptimally to standard-dose aflibercept. Methods: This retrospective analysis included eyes with clinically significant disease activity on monthly therapy (AMT) (injection interval ≤35 days) or clinically significant increased activity on extension (IAE) (injection interval >36 days) that were switched from aflibercept 2 mg to aflibercept HD (3 mg to 4 mg). Outcomes were assessed at baseline, after injections 1 through 4, and at 6, 9, and 12 months. Results: Overall, 318 eyes of 288 adult patients were analyzed (eyes with nAMD: 59 AMT, 147 IAE; eyes with DME: 50 AMT, 62 IAE). Most of the study cohort received aflibercept HD 3 mg (nAMD: 73% AMT and 58% IAE; DME: 49% AMT and 68% IAE); the remainder received 4 mg. The mean best VA improved significantly with AMT and was maintained with IAE. In all groups, the central subfield thickness decreased significantly and the mean injection intervals increased or remained stable. No new safety signals were observed. Conclusions: Aflibercept HD might improve outcomes while decreasing treatment burden for eyes that respond suboptimally to standard dosing.

Latest Trends in Retinopathy of Prematurity: Research on Risk Factors, Diagnostic Methods and Therapies

Retinopathy of prematurity (ROP) is a vasoproliferative disorder with an imminent risk of blindness, in cases where early diagnosis and treatment are not performed. The doctors' constant motivation to give these fragile beings a chance at life with optimal visual acuity has never stopped, since Terry first described this condition. Thus, throughout time, several specific advancements have been made in the management of ROP. Apart from the most known risk factors, this narrative review brings to light the latest research about new potential risk factors, such as: proteinuria, insulin-like growth factor 1 (IGF-1) and blood transfusions. Digital imaging has revolutionized the management of retinal pathologies, and it is more and more used in identifying and staging ROP, particularly in the disadvantaged regions by the means of telescreening. Moreover, optical coherence tomography (OCT) and automated diagnostic tools based on deep learning offer new perspectives on the ROP diagnosis. The new therapeutical trend based on the use of anti-VEGF agents is increasingly used in the treatment of ROP patients, and recent research sustains the theory according to which these agents do not interfere with the neurodevelopment of premature babies.

Protein and polypeptide mediated delivery to the eye

Hybrid or recombinant protein-polymers, peptide-based biomaterials, and antibody-targeted therapeutics are widely explored for various ocular conditions and vision correction. They have been noted for their potential biocompatibility, potency, adaptability, and opportunities for sustained drug delivery. Unique to peptide and protein therapeutics, their production by cellular translation allows their precise modification through genetic engineering. To a greater extent than drug delivery to other systems, delivery to the eye can benefit from the combination of locally-targeted administration and protein-based specificity. Consequently, a range of delivery platforms and administration methods have been exploited to address the ocular delivery of peptide and protein biomaterials. This review discusses a sample of preclinical and clinical opportunities for peptide-based drug delivery to the eye.

Aflibercept versus Faricimab in the Treatment of Neovascular Age-Related Macular Degeneration and Diabetic Macular Edema: A Review

Diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD) are common retinal vascular diseases responsible for most blindness in the working-age and older population in developed countries. Currently, anti-VEGF agents that block VEGF family ligands, including ranibizumab, bevacizumab (off-label use), brolucizumab, and aflibercept, are the first-line treatment for nAMD and DME. However, due to the complex pathophysiological background of nAMD and DME, non-response, resistance during anti-VEGF therapy, and relapses of the disease are still observed. Moreover, frequent injections are a psychological and economic burden for patients, leading to inadequate adhesion to therapy and a higher risk of complications. Therefore, therapeutic methods are strongly needed to develop and improve, allowing for more satisfactory disease management and lower treatment burden. Currently, the Ang/Tie-2 pathway is a promising therapeutic target for retinal vascular diseases. Faricimab is the first bispecific monoclonal antibody for intravitreal use that can neutralize VEGF and Ang-2. Due to the prolonged activity, faricimab allows extending the interval between successive injections up to three or four months in nAMD and DME patients, which can be a significant benefit for patients and an alternative to implanted drug delivery systems.

Current Trends in Clinical Characteristics, Diagnosis, and Treatment of Polypoidal Choroidal Vasculopathy: A Perspective from Vietnam

Polypoidal choroidal vasculopathy (PCV) is a common choroidal disease in the Asian population including Vietnam and is characterized by subretinal red-orange nodules, pigmented epithelium detachment, and massive subretinal hemorrhage. The recent focus on PCV in Vietnam can be attributed to advancements in PCV diagnosis and treatment. However, there is a scarcity of published literature and clinical data on PCV in the Vietnamese population, highlighting a key knowledge gap in this region. In order to address this gap, we gathered the opinions of experienced clinicians and retinal experts in Vietnam and reviewed available medical literature with the aim of: (i) providing an overview of PCV in the Vietnamese population—in terms of epidemiology, clinical characteristics, and management; (ii) tailoring international/national guidelines for the diagnosis and management of PCV, in line with available resources and medical equipment in Vietnam; and (iii) identifying gaps in clinical data in order to guide future PCV research in Vietnam and other countries with similar clinical conditions. The present review will enable healthcare providers and researchers to gain insight into current clinical practices and the limitations of PCV management in Vietnam and provide optimal and effective solutions.

Rapidly dissolving bilayer microneedles enabling minimally invasive and efficient protein delivery to the posterior segment of the eye

The discovery of proteins that neutralise vascular endothelial growth factors, such as pegaptanib, ranibizumab and aflibercept, can inhibit the process of angiogenesis, thereby restoring eyesight in individuals with retinal vascular disorders. However, due to the posterior location and chronic nature of retinal diseases, a safe and effective intraocular protein delivery system is currently lacking. Thus, dissolving bilayer microneedles (MNs) with the potential to deliver proteins to the back of the eye in an efficient and minimally invasive manner were developed in this study. A model protein, ovalbumin (OVA), was incorporated into MNs fabricated from different polymers, including hyaluronic acid (HA), polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). Optimised PVA/PVP MNs were demonstrated to be robust enough to pierce porcine sclera with > 75% of the needle length penetrating the sclera and dissolving within 150 s. SDS-PAGE and OVA-specific ELISA revealed that the bioactivity of the model protein was maintained during the manufacture of MNs. In hen's egg-chorioallantoic membrane test, MNs fabricated from all chosen polymers were classified as non-irritants. Furthermore, ex vivo permeation studies showed that optimised MNs could permeate 86.99 ± 7.37% of OVA through the sclera, twice that of the needle-free patch (42.16 ± 3.95%), highlighting the capability of MNs to circumvent physical barriers and promote protein delivery to the posterior segment of the eye. In this work, a novel, efficient and safe intraocular protein delivery system was successfully established.

Microvolume Analysis of Aflibercept in Aqueous Humor Using Mass Spectrometry

Purpose

To develop a microvolume analytical method for measurement of the aflibercept concentration in human intraocular fluid and plasma.

Methods

We analyzed trace amounts of aflibercept in human aqueous humor using Fab-selective proteolysis and nano-surface and molecular-orientation limited (nSMOL) proteolysis, coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS). Patients with age-related macular degeneration or diabetic macular edema were recruited. Just after an injection of 50 µL of aflibercept, regurgitate from needle holes was collected with a micropipette pressed to the side of the injection hole within 10 seconds. The median amount of regurgitate was 4 µL (range, 1–18 µL).

Results

In human plasma, the aflibercept concentration ranged between 0.195 and 50 µg/mL when using the quantitative signature peptide IIWDSR (aa. 56–61) present on the vascular endothelial growth factor receptor 1 domain of aflibercept. The method was validated by evaluating its linearity, carryover, selectivity, accuracy and precision, dilution effect, and sample/processing stability. As only a minimal amount of regurgitate through needle holes can be sampled, we performed and verified the aflibercept assay using patient samples after 1:10 dilution with control human plasma, a recognized diluent. The median concentration of aflibercept in the regurgitate was 240 µg/mL (range, 13–4300 µg/mL).

Conclusions

Our findings indicate that the aflibercept assay using human intraocular fluid can be reliably performed using nSMOL coupled with LC-MS/MS.

Translational Relevance

This technique for quantifying aflibercept in the regurgitate suggests that the amount of drug lost post-injection can be ignored, even in patients with a relatively large leak after vitreous injection. This new methodology suggests possible therapeutic responses and may be employed as a general analytical method for trapping many biologics, such as vascular endothelial growth factor, in various types of clinical samples, unaffected by proteinaceous or small organic pharmaceuticals.

Intravitreal Anti-vascular Endothelial Growth Factor Injection for Retinopathy of Prematurity: A Systematic Review and Meta-Analysis

Background

Laser photocoagulation and/or intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections constitute the current standard treatment for retinopathy of prematurity (ROP). This systematic review and meta-analysis aimed to assess the efficacy and safety of anti-VEGF monotherapy for ROP treatment using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Methods

We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. We included randomized controlled trials (RCTs) that compared intravitreal anti-VEGF monotherapy (e.g., bevacizumab, ranibizumab, aflibercept, and pegaptanib) with laser photocoagulation in preterm infants with ROP. We evaluated the rates of recurrence, treatment switching, retreatment, adverse events, and mortality. The risk ratio (RR) was used to represent dichotomous outcomes. Data were pooled using the inverse variance weighting method. The quality of evidence was assessed using the GRADE approach. Risk of bias was assessed using the Revised Cochrane risk of bias tool for randomized trials.

Results

Seven RCTs (n = 579; 1,158 eyes) were deemed eligible. Three RCTs had an overall low risk of bias, three had some concerns, and one had an overall high risk of bias. The pooled effect estimate showed a statistically significant reduction in adverse events in favor of anti-VEGF monotherapy [RR = 0.17, 95% confidence interval (CI) 0.07–0.44]. The pooled analysis showed no significant difference between the anti-VEGF and laser groups in terms of recurrence rate (RR = 1.56, 95% CI 0.23–10.54), treatment switching (RR = 2.92, 95% CI 0.40–21.05), retreatment (RR = 1.56, 95% CI 0.35–6.96), and mortality rate (RR = 1.28, 95% CI 0.48–3.41).

Conclusion

Overall, intravitreal anti-VEGF monotherapy was associated with fewer adverse events than laser therapy, rated as high quality of evidence according to the GRADE criteria. Pooled analysis revealed no significant difference between the two arms with respect to the recurrence rate, treatment switching, retreatment, and mortality rate, with quality of evidence ranging from moderate to very low as per the GRADE approach.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/#recordDetails], identifier [CRD42021270077].

Biomarkers as Predictive Factors of Anti-VEGF Response

Age-related macular degeneration is the main cause of irreversible vision in developed countries, and intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are the current gold standard treatment today. Although anti-VEGF treatment results in important improvements in the course of this disease, there is a considerable number of patients not responding to the standardized protocols. The knowledge of how a patient will respond or how frequently retreatment might be required would be vital in planning treatment schedules, saving both resource utilization and financial costs, but today, there is not an ideal biomarker to use as a predictive response to ranibizumab therapy. Whole blood and blood mononuclear cells are the samples most studied; however, few reports are available on other important biofluid samples for studying this disease, such as aqueous humor. Moreover, the great majority of studies carried out to date were focused on the search for SNPs in genes related to AMD risk factors, but miRNAs, proteomic and metabolomics studies have rarely been conducted in anti-VEGF-treated samples. Here, we propose that genomic, proteomic and/or metabolomic markers could be used not alone but in combination with other methods, such as specific clinic characteristics, to identify patients with a poor response to anti-VEGF treatment to establish patient-specific treatment plans.

Ultrasound and Microbubbles for the Treatment of Ocular Diseases: From Preclinical Research towards Clinical Application

The unique anatomy of the eye and the presence of various biological barriers make efficacious ocular drug delivery challenging, particularly in the treatment of posterior eye diseases. This review focuses on the combination of ultrasound and microbubbles (USMB) as a minimally invasive method to improve the efficacy and targeting of ocular drug delivery. An extensive overview is given of the in vitro and in vivo studies investigating the mechanical effects of ultrasound-driven microbubbles aiming to: (i) temporarily disrupt the blood–retina barrier in order to enhance the delivery of systemically administered drugs into the eye, (ii) induce intracellular uptake of anticancer drugs and macromolecules and (iii) achieve targeted delivery of genes, for the treatment of ocular malignancies and degenerative diseases. Finally, the safety and tolerability aspects of USMB, essential for the translation of USMB to the clinic, are discussed.

Metabolomics in Retinal Diseases: An Update

Retinal diseases are a leading cause of visual loss and blindness, affecting a significant proportion of the population worldwide and having a detrimental impact on quality of life, with consequent economic burden. The retina is highly metabolically active, and a number of retinal diseases are associated with metabolic dysfunction. To better understand the pathogenesis underlying such retinopathies, new technology has been developed to elucidate the mechanism behind retinal diseases. Metabolomics is a relatively new "omics" technology, which has developed subsequent to genomics, transcriptomics, and proteomics. This new technology can provide qualitative and quantitative information about low-molecular-weight metabolites (M.W. < 1500 Da) in a given biological system, which shed light on the physiological or pathological state of a cell or tissue sample at a particular time point. In this article we provide an extensive review of the application of metabolomics to retinal diseases, with focus on age-related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), glaucoma, and retinitis pigmentosa (RP).

Ocular Pharmacokinetics of Intravitreally Injected Protein Therapeutics: Comparison among Standard-of-Care Formats

The current standard of care for antivascular endothelial growth factor (VEGF) treatment requires frequent intravitreal (IVT) injections of protein therapeutics, as a result of limited retention within the eye. A thorough understanding of the determinants of ocular pharmacokinetics (PK) and its translation across species is an essential prerequisite for developing more durable treatments. In this work, we studied the ocular PK in macaques of the protein formats that comprise today's anti-VEGF standard of care. Cynomolgus monkeys received a single IVT injection of a single-chain variable fragment (scFv, brolucizumab), antigen-binding fragment (Fab, ranibizumab), fragment crystallizable-fusion protein (Fc-fusion, aflibercept), or immunoglobulin G monoclonal antibody (IgG, VA2 CrossMAb). Drug concentrations were determined in aqueous humor samples collected up to 42 days postinjection using immunoassay methods. The ocular half-life (t_1/2) was 2.28, 2.62, 3.13, and 3.26 days for scFv, Fab, Fc-fusion, and IgG, respectively. A correlation with human t_1/2 values from the literature confirmed the translational significance of the cynomolgus monkey as an animal model for ocular research. The relation between ocular t_1/2 and molecular size was also investigated. Size was inferred from the molecular weight (MW) or determined experimentally by dynamic light scattering. The MW and hydrodynamic radius were found to be good predictors for the ocular t_1/2 of globular proteins. The analysis showed that molecular size is a determinant of ocular disposition and may be used in lieu of dedicated PK studies in animals.

Evaluation of Blood Coagulation Parameters and ADMA, NO, IL-6, and IL-18 Serum Levels in Patients with Neovascular AMD before, during, and after the Initial Loading Phase of Intravitreal Aflibercept

We evaluated the effect of intravitreal injections of aflibercept (IVA) on blood coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT), as well as asymmetric dimethylarginine (ADMA), nitric oxide (NO), interleukin 6 (IL-6), and interleukin 18 (IL-18) serum levels in patients with neovascular AMD (nAMD). Twenty-two eyes of 22 patients with nAMD were included. Parameters were evaluated before and 2–3 days after the first IVA injection, and then immediately before and 2–3 days after the third IVA injection. We revealed prolongation of the TT after the initial loading phase of IVA (p = 0.041) and a significant increase in IL-18 serum concentration immediately before the third IVA administration compared to baseline (p = 0.037). There were no statistically significant differences of other parameters and PT, APTT, ADMA, NO, and IL-6 values remained within the normal range at each of the time points of the study. Our results suggest that repeated IVA administration may affect the common blood coagulation pathway, which manifests as a prolongation of the TT value. Furthermore, we showed a significant increase in serum concentration of the pro-inflammatory cytokineIL-18during the initial loading phase of IVA.

Subconjunctival Aflibercept for the Treatment of Formed Corneal Neovascularization

PURPOSE

To evaluate the effect of a single subconjunctival aflibercept injection on formed corneal neovascularization.

METHODS

A prospective clinical trial, conducted at a single tertiary medical center. Included were consecutive patients with corneal pathologies complicated by corneal neovascularization, who were candidates for anti-vascular endothelial growth factor treatment at the discretion of a cornea specialist. A single subconjunctival injection of 0.08 mL of Aflibercept (Eylea 25 mg/mL) was administered near the limbus in proximity to the areas of maximal pathological neovascularization. Follow-up visits were scheduled on days 7, 30, 60, and 90 following injection. Best-corrected visual acuity (BCVA), intraocular pressure, slitlamp examination, digital cornea photography, specular microscopy, and anterior-segment optical coherence tomography were documented at each visit. The images were graded by a masked observer for density, extent, and centricity of corneal vascularization.

RESULTS

Six eyes of six patients were analyzed. No clinically significant ocular or systemic adverse events were documented. No change was noted in extent, density, or centricity of corneal blood vessels at seven, 30, and 90 days after injection (P>0.1 for all time point comparisons, Friedman test). Best-corrected visual acuity fluctuated insignificantly in 5/6 patients during follow-up time, and objective but not subjective improvement of BCVA was noted in one patient with no concurrent change of neovascularization. The recruitment has therefore halted prematurely.

CONCLUSIONS

A single subconjunctival aflibercept injection seems to be well tolerated. However, it is ineffective for regressing formed corneal neovascularization.

Anti-VEGF DNA-based aptamers in cancer therapeutics and diagnostics

The vascular endothelial growth factor (VEGF) family and its receptors play fundamental roles not only in physiological but also in pathological angiogenesis, characteristic of cancer progression. Aiming at finding putative treatments for several malignancies, various small molecules, antibodies, or protein-based drugs have been evaluated in vitro and in vivo as VEGF inhibitors, providing efficient agents approved for clinical use. Due to the high clinical importance of VEGF, also a great number of anti-VEGF nucleic acid-based aptamers-that is, oligonucleotides able to bind with high affinity and specificity a selected biological target-have been developed as promising agents in anticancer strategies. Notable research efforts have been made in optimization processes of the identified aptamers, searching for increased target affinity and/or bioactivity by exploring structural analogues of the lead compounds. This review is focused on recent studies devoted to the development of DNA-based aptamers designed to target VEGF. Their therapeutic potential as well as their significance in the construction of highly selective biosensors is here discussed.

Understanding the Half-Life Extension of Intravitreally Administered Antibodies Binding to Ocular Albumin

The burden associated with frequent injections of current intravitreal (IVT) therapeutics may be reduced by long-acting delivery strategies. Binding to serum albumin has been shown to extend the ocular half-life in rabbits, however, the underlying molecular mechanisms and translational relevance remain unclear. The aim of this work was to characterize the in vitro and in vivo formation of complexes between human serum albumin (HSA) and an antigen-binding fragment of a rabbit antibody linked to an anti-HSA nanobody (FabA). The ocular and systemic pharmacokinetics of 3H-labeled FabA (0.05 mg/eye IVT) co-formulated with HSA (1 and 15 nmol/eye) were assessed in Dutch belted rabbits. Next, FabA was incubated in vitreous samples from cynomolgus monkeys and human donors (healthy and diseased) supplemented with species-specific serum albumin. Finally, the FabA-albumin complexes formed in vitro and in vivo were analyzed by radio-size exclusion chromatography. A 3-fold increase in FabA vitreal exposure and half-life was observed in rabbits co-administered with 15 nmol HSA compared to 1 nmol and a control arm. The different pharmacokinetic behavior was explained with the formation of higher molecular weight FabA-albumin complexes. The analysis of vitreous samples revealed the existence of predominantly 1:1 complexes at endogenous or low concentrations of supplemented albumin. A shift towards 1:2 complexes was observed with increasing albumin concentrations. Overall, these results suggest that endogenous vitreal albumin concentrations are insufficient for half-life extension and warrant supplementation in the dosing formulation.

Injectable in-situ gel depot system for targeted delivery of biologics to the retina

In current clinical settings, frequent intravitreal (IVT) injections of anti-vascular endothelial growth factors are used due to their short in-vivo half-life and rapid clearance from the back of the eye. The IVT injections are associated with pain, risk of infection, retinal detachment, and financial burden. Biologics molecules can undergo physical, chemical, and enzymatic degradation during formulation development and in the biological environment. Moreover, the complex ocular structures also act as a rate-limiting barrier for these biologics. Thus, delivering stable and clinically relevant biologics concentration to the back of the eye is still a challenge. Compare to other drug delivery platforms, injectable in-situ gelling depot systems (IISGDs) have emerged as an effective system for biologics delivery. In this review, we have discussed various biologics used in ocular therapeutics and their associated challenges. Different routes of delivery and associated tissue barriers are also discussed. Different types of IISGDs developed to date for biologics delivery to the back of the eye were also covered. To conclude, various critical parameters related to the formulation development process and injectable depot systems that need careful consideration and further investigations were highlighted.

Intravitreal hydrogels for sustained release of therapeutic proteins

This review highlights how hydrogel formulations can improve intravitreal protein delivery to the posterior segment of the eye in order to increase therapeutic outcome and patient compliance. Several therapeutic proteins have shown excellent clinical successes for the treatment of various intraocular diseases. However, drug delivery to the posterior segment of the eye faces significant challenges due to multiple physiological barriers preventing drugs from reaching the retina, among which intravitreal protein instability and rapid clearance from the site of injection. Hence, frequent injections are required to maintain therapeutic levels. Moreover, because the world population ages, the number of patients suffering from ocular diseases, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR) is increasing and causing increased health care costs. Therefore, there is a growing need for suitable delivery systems able to tackle the current limitations in retinal protein delivery, which also may reduce costs. Hydrogels have shown to be promising delivery systems capable of sustaining release of therapeutic proteins and thus extending their local presence. Here, an extensive overview of preclinically developed intravitreal hydrogels is provided with attention to the rational design of clinically useful intravitreal systems. The currently used polymers, crosslinking mechanisms, in vitro/in vivo models and advancements are discussed together with the limitations and future perspective of these biomaterials.

Effect of Repeated Intravitreal Ranibizumab and Aflibercept Injections on the Cornea in Patients with Age-Related Macular Degeneration

Purpose

To assess the effect of repeated intravitreal ranibizumab injections (RI) and aflibercept injections (AI) on the corneal endothelium and central corneal thickness (CCT) in patients with age-related macular degeneration (AMD).

Materials and Methods

In the retrospective study, 110 eyes of 106 patients, aged 52 to 93 years, were analyzed. Fifty eyes were treated only with RI (I group), and 60 eyes were treated only with AI (II group). Every patient received one intravitreal injection of 0.5 mg of ranibizumab once a month or 2 mg of aflibercept for 3 subsequent months. Each patient received only 3 injections during the whole observation period. Corneal analysis was obtained with the specular microscope. Examinations were performed before initial treatment, after each injection, and 6 months after the first injection. Analysis included corneal endothelial cell density (ECD), hexagonal cell percentage (% Hex), coefficient of variation (CoV), and CCT.

Results

There was a statistically significant ECD loss, regardless of the type of the anti-VEGF agent. The mean ECD value in the I group was 2397 ± 459 cells/mm² before RI, 2389 ± 459 cells/mm² after the first RI, 2386 ± 467 cells/mm² after the second RI, 2378 ± 475 cells/mm² after the third RI, and 2357 ± 460 cells/mm² 6 months after the first RI. The mean ECD value in the II group was 2448 ± 493 cells/mm² before treatment, 2456 ± 498 cells/mm² after the first AI, 2426 ± 496 cells/mm² after the second AI, 2402 ± 488 cells/mm² after the third AI, and 2348 ± 473 cells/mm² 6 months after the first AI. In comparison with the group treated with RI, the group treated with AI presented a greater ECD loss at each measuring point. The percentage of hexagonal cells was decreased in both groups. There was a slight increase in polymegathism in both treated groups. Ranibizumab proved to cause a small increase in CCT, while CCT remained unchanged in the aflibercept group.

Conclusions

Repeated intravitreal injections of 0.5 mg of ranibizumab or 2 mg of aflibercept can influence the morphology of the corneal endothelium but not CCT.

Case Series on Initial Responses to Intravitreal Brolucizumab in Patients with Recalcitrant Chronic Wet Age-Related Macular Degeneration

Purpose

To report a case series of initial responses to intravitreal brolucizumab in patients already undergoing anti-VEGF therapy for wet age-related macular degeneration.

Case Series

Six eyes (6 patients) with a history of wet age-related macular degeneration presented with either decline in vision or no improvement while undergoing treatment with anti-VEGF therapy – aflibercept or bevacizumab. Patients were switched to intravitreal brolucizumab. Four weeks post-injection, there was no significant change in visual acuity. Optical coherence tomography scans were taken and improved IRF/SRF, central macular thickness and average pericentral thickness were observed in all 6 patients. No serious adverse reactions were observed, including signs of vasculitis or increase in anterior chamber cell count at the 4-week follow-up for all 6 patients.

Conclusion

Intravitreal brolucizumab appears to be a safe and limitedly effective option for patients with recalcitrant CNV from wet AMD.

Complete RPE and outer retinal atrophy in patients receiving anti-VEGF treatment for neovascular age-related macular degeneration

Importance

Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness with several intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents available for its management such as aflibercept, bevacizumab, and ranibizumab. However, direct comparisons between these three agents among the same patient population are limited.

Objective

To assess the rate and growth of complete retinal pigment epithelium and outer retinal atrophy (cRORA) in eyes with nAMD treated with aflibercept, bevacizumab, and/or ranibizumab.

Method

Retrospective cohort study of patients with treatment-naïve neovascular AMD seen at an academic hospital between October 2006 and February 2019. Study eyes were treated with intravitreal injections of aflibercept, bevacizumab, and/or ranibizumab and followed for two years.

Main outcomes and measures

cRORA prevalence, location, size, and growth rate. Eyes were imaged with Cirrus spectral domain optical coherence tomography (SD-OCT). Presence and size of cRORA were calculated using the FDA-approved Advanced RPE Analysis software. Linear regression models were used to correlate cRORA progression with baseline demographic and ocular characteristics, anti-VEGF drug, and number of injections. Unpaired t-tests, ANOVA, and linear regression models were computed with SAS 9.4.

Results

197 eyes from 158 patients (mean age 78.9, 62.9% women) received an average of 13 anti-VEGF injections over 24 months. 22% developed new cRORA. Mean cRORA area increased from 1.71 mm² to 2.93 mm². At 24 months, eyes with 11+ injections had significantly less cRORA area (11+ injections, 4.02 mm²; ≤ 10 injections, 2.46 mm²; p = 0.01) and growth rate (11+ injections, 0.41 mm²/year; ≤ 10 injections, 1.05 mm²/year; p = 0.02). Choice of anti-VEGF drug yielded no significant difference in cRORA progression.

Conclusions and relevance

Treating nAMD with aflibercept, bevacizumab or ranibizumab demonstrated comparable cRORA development at 24 months. Number of injections inversely correlated with cRORA area and growth. These results warrant further investigation in the pathophysiology of cRORA in anti-VEGF treated eyes.

A Meta-Analysis of Cardiovascular Events Associated with Intravitreal Anti-VEGF Treatment in Patients with Retinal Vein Occlusion

Purpose: Retinal vein occlusion is associated with an increased risk of cardiovascular diseases. Anti-vascular endothelial growth factor has been widely used as a treatment option. However, the systemic safety of intravitreal anti-vascular endothelial growth factor for retinal vein occlusion patients is still unclear.Materials and Methods: A meta-analysis was conducted to investigate all randomized controlled trials published up to February 2019 of retinal vein occlusion patients who received intravitreal anti-vascular endothelial growth factor vs. control treatments. Fixed effect models were used and results were reported as odds ratios and 95% confidence intervals.Results: Eight trials that evaluated 2320 patients were retrieved. Anti-vascular endothelial growth factor did not significantly increase the risks of cardiovascular events (odds ratio,1.54; 95% confidence interval, 0.66-3.57), hypertension (odds ratio, 0.92; 95% confidence interval, 0.63-1.33), or heart rate disorders (odds ratio,1.53; 95% confidence interval, 0.37-6.28) when compared with control treatment. Subgroup analyses did not show a significant increase of cardiovascular events in aflibercept (odds ratio,1.96; 95% confidence interval, 0.44-8.81) vs. ranibizumab trials (odds ratio, 1.47; 95% confidence interval, 0.54-4.02); 0.5 mg ranibizumab trials (odds ratio, 1.73; 95% confidence interval, 0.61-4.96) vs. 0.3 mg ranibizumab trials (odds ratio, 0.70; 95% confidence interval, 0.14-3.59); nor branch retinal vein occlusion (odds ratio, 1.32; 95% confidence interval, 0.40-4.33) vs. central retinal vein occlusion trials (odds ratio, 1.93; 95% confidence interval, 0.59-6.29).Conclusions: Intravitreal administration of anti-vascular endothelial growth factor did not significantly increase the risks of cardiovascular events, hypertension or heart rate disorders in retinal vein occlusion patients.

Emerging Therapies in Neovascular Age-Related Macular Degeneration in 2020

Age-related macular degeneration (AMD) is one of the most common causes of vision loss. Advanced forms of AMD are seen in primarily 2 types-neovascular AMD (nAMD) with the presence of choroid neovascularization and nonneovascular AMD (nnAMD) with geographic atrophy. Although there are 4 anti-vascular endothelial growth factor drugs either widely used or approved for the former, there are no current treatments for the latter. This review will highlight upcoming treatments for AMD currently in clinical trials. For nAMD: Abicipar pegol, an intravitreal anti-vascular endothelial growth factor based on designed ankyrin repeat proteins (DARP) in protein, is currently pending approval. Conbercept and Faricimab, 2 intravitreal anti-growth factors, are currently in phase 3. Nine other upcoming agents have at least produced results in the 2A phase including intravitreal injections (KSI-301, OPT-302, RGX-314, ICON-1, and DE-122), depot (GB-102), drug reservoir (PDS), topical drops (PAN-90806), and oral formulations (AKST4290). We summarize all the newer molecules.

Aptamers as Therapeutic Agents: Has the Initial Euphoria Subsided?

Aptamers are synthetic DNA or RNA oligonucleotide ligands with great potential for therapeutic applications. A vast number of disease-related targets have been used to identify agonistic, antagonistic, or inhibitory aptamers, or aptamer-based targeting ligands. However, only a few aptamers have reached late-stage clinical trials so far and the commercial infrastructure is still far behind that of other therapeutic agents such as monoclonal antibodies. The desirable properties of aptamers such as selectivity, chemical flexibility, or cost-efficiency are faced by challenges, including a short half-life in vivo, immunogenicity, and entrapment in cellular organelles. Aptamer research is still in an early stage, and a deeper understanding of their structure, target interactions, and pharmacokinetics is necessary to catch up to the clinical market. In this review, we will discuss the benefits and limitations in the development of therapeutic aptamers, as well as the advances and future directions of aptamer research. The progress towards effective therapies seems to be slow, but it has not stopped and the best is yet to come.

Retinal arterial occlusive vasculitis following intravitreal brolucizumab administration

Purpose

To describe retinal arterial occlusion and vasculitis following intravitreal brolucizumab administration in a patient with neovascular age-related macular degeneration (nAMD).

Observation

An 88-year-old Caucasian woman with neovascular age-related macular degeneration (nAMD) complained of painless loss of vision with light sensitivity in both eyes (OU) four weeks after bilateral intravitreal brolucizumab. Upon examination, her visual acuity decreased to 20/40 in the right eye (OD) and 20/50 in the left eye (OS). Examination revealed 0.5+ and 1+ anterior chamber cells in OD and OS, respectively. The patient was treated with 1% prednisolone acetate eyedrops in both eyes, and after several weeks, the anterior chamber cells resolved. However, the patient still reported a decline in visual acuity (VA). Fluorescein angiography (FA) revealed retinal arterial occlusion, vasculitis, and optic nerve inflammation in the left eye. Retinal intra-arterial grayish materials were also detected. Laboratory evaluations were performed for common infectious and inflammatory causes and were normal or negative. A delayed inflammatory reaction to brolucizumab was suspected as the cause of the ocular inflammation and retinal vasculitis. An intravitreal dexamethasone implant was inserted into the left eye to treat the inflammation. One week after the dexamethasone implant, VA improved to 20/40 in OU; FA showed improvement, but residual peri-vascular leakage remained.

Conclusion

Medication-associated uveitis is a rare adverse effect that can lead to vision loss. The index report illustrates a case of intraocular inflammation, retinal arterial vaso-occlusion and vasculitis associated with intravitreal brolucizumab. The delay in developing uveitis suggests that the inflammation is due to a delayed hypersensitivity reaction which can occur several days or weeks after administration of the inciting agent. Recently, several cases of uveitis and vasculitis associated with brolucizumab have been presented and those cases have similar features compared to the index case (1). Therapy with steroids (either intraocular or systemic), after infectious etiologies have been excluded, may be beneficial in halting inflammation and preventing further vision loss.

Cell-based approaches towards treating age-related macular degeneration

Age-related macular degeneration as one of the most common causes of worldwide vision loss needs a proper approach for treatment. Therein, cell therapy and regenerative medicine can hold a great promise to be an effective approach. Accordingly, some preclinical and clinical studies were conducted to search around the therapeutic influence of stem cells in Age-related macular degeneration models and subjects. Hereupon, the purpose of the current review is to discuss the mechanisms of age-related macular degeneration, appropriate animal models along with suitable dosage and route of stem cell administration for its treatment.

In vivo characterization of RC28-E, a fusion protein targeting VEGF and bFGF: Pharmacokinetics and ocular distribution in primates

Administration of RC28-E, a VEGF/bFGF dual decoy receptor (IgG1 Fc-fusion protein), have shown relative therapeutic value in ocular in vivo models, including laser-induced choroidal neovascularization (CNV) in monkeys and streptozotocin (STZ)-induced diabetic retinopathy (DR) in rats. In the present study, we have elucidated the pharmacokinetics profiles of RC28-E at the systemic, vitreous and aqueous humor after administration in a primate model (Macaca fascicularis). Moreover, here we tease out the ocular tissue distribution of RC28-E after intravitreal administration, and we also determine the systemic bioavailability after both intravitreal and intravenous administration. Our results show that RC28-E is rapidly and well-distributed into ocular tissues after intravitreal administration. Drug exposure in choroid and retina was approximately one-quarter and one-twelfth of that in vitreous humor, while its half-life in vitreous and aqueous humor were well-sustained (3.3 and 3.0 days). Remarkably, RC28-E could cross the blood-ocular barrier, and the systemic bioavailability of RC28-E was ~25%. No drug accumulation after multiple administration was noticed, but low titers of antibody produce against RC28-E were detected. Overall, RC28-E exhibited high clinical value due to adequate pharmacokinetic profiling, safety and efficacy.

Intravitreal aflibercept injection in Indian eyes with retinopathy of prematurity

Purpose:

To study the efficacy of intravitreal Aflibercept, an anti Vascular Endothelial Growth factor, (anti-VEGF) in Retinopathy of Prematurity (ROP).

Methods:

This was a retrospective, interventional consecutive case series of 46 Indian eyes which received intravitreal injection of Aflibercept for High risk Prethreshold ROP, Threshold ROP, and Aggressive-Posterior ROP (AP-ROP).

Results:

Aflibercept was effective in achieving the primary endpoint, namely regression of ROP following the injection in all 46 eyes (100%) at one week following the injection. 32.6% (15/46) of eyes achieved secondary endpoint namely complete vascularization, with no recurrence of ROP at varying time intervals: as early as 15 weeks to as late as 29 weeks after injection, at intervals ranging from 49 to 64 weeks PCA.

Conclusion:

Intravitreal Aflibercept was effective in inducing complete regression of all types of ROP in all the eyes in our series. In addition, 32.6% of cases did not need a secondary intervention, with no recurrence of ROP and complete vascularization of the retina. In 81.8% of Zone I ROP eyes, Aflibercept facilitated continuation of retinal vascular development following regression of ROP, resulting in less extensive laser during treatment of ROP recurrence. This is the largest series of Aflibercept in ROP, till date as per MEDLINE search.

Blocking interleukin-6 trans-signaling protects against renal fibrosis by suppressing STAT3 activation

Rationale: Renal fibrosis is the terminal manifestation of chronic and irreversible renal disease. Effective therapies other than dialysis are extremely limited. In this study, we investigated the potential effects of targeting elevated interleukin-6 (IL-6) levels in the treatment of renal fibrosis.

Methods: Fc-gp130 was used to specifically block IL-6 trans-signaling. Unilateral ureteral occlusion (UUO) and ischemia reperfusion (IR) mouse models were constructed to investigate the therapeutic effect of Fc-gp130 on renal fibrosis. The role of IL-6 trans-signaling and phosphorylation of signal transducer and activator of transcription (STAT) 3 in regulating fibroblast accumulation and extracellular matrix protein deposition were evaluated in cell experiments and mouse models.

Results: The kidneys of mice with UUO were found to have elevated soluble IL-6 receptor (sIL-6R) levels in the progression of fibrosis. Fc-gp130 attenuated renal fibrosis in mice, as evidenced by reductions in tubular atrophy and the production of extracellular matrix protein. Blockade of IL-6 trans-signaling with Fc-gp130 also reduced inflammation levels, immune cell infiltration, and profibrotic cytokines expression in renal tissue, with decreased STAT3 phosphorylation and reduced fibroblast accumulation in the renal tissue. In vitro, Fc-gp130 also reduced the phosphorylation of STAT3 induced by transforming growth factor (TGF)-β1 in fibroblasts. Furthermore, the therapeutic effect of Fc-gp130 was confirmed in a model of acute kidney injury-chronic kidney disease.

Conclusion: Overall, IL-6 trans-signaling may contribute to crucial events in the development of renal fibrosis, and the targeting of IL-6 trans-signaling by Fc-gp130 may provide a novel therapeutic strategy for the treatment of renal fibrosis.

Intravitreal aflibercept efficacy in neovascular age-related macular degeneration with suboptimal response to anti-vascular endothelial growth factor-A therapy

IMPORTANCE

To provide new insights into aflibercept effect in non-naive-treated patients with neovascular age-related macular degeneration.

PURPOSE

To assess the efficacy of intravitreal aflibercept in patients with neovascular age-related macular degeneration without optimal response to previous anti-vascular endothelial growth factor A therapy.

DESIGN

Single-arm, multi-centre, prospective study.

PARTICIPANTS

Patients ⩾50 years with active neovascular age-related macular degeneration, best-corrected visual acuity between 20/32 and 20/320 with suboptimal response to ranibizumab or bevacizumab.

METHODS

Aflibercept was administered monthly (3-first months), and bimonthly thereafter until month 8. Anatomical and functional outcomes were assessed.

MAIN OUTCOME MEASURE

Percentage of eyes without intra or subretinal fluid on optical coherence tomography after 3-monthly loading doses of aflibercept.

RESULTS

A total of 46 patients were included. At week 12, 45.7% (95% confidence interval: 31.5%-60.1%) of eyes showed no fluid on optical coherence tomography. The mean (standard deviation) best-corrected visual acuity increased from 65.1 (8.3) to 69.6 (8.1) letters (+4.5 (5.8) p < 0.0001) and was stabilized at week 40 as compared to baseline. Mean central macular thickness decreased from 430 (119) µm to 323 (100) µm at week 12 (-107 (90) µm, p < 0.0001) and was reduced at week 40 (-46 (111) µm, p = 0.0056). At week 40, 21.7% (95% confidence interval: 9.8%-33.7%) had no fluid. There was a case of presumed noninfectious endophthalmitis that was successfully managed.

CONCLUSION

Almost half of patients presented no fluid on optical coherence tomography at week 12, and there was a clinically significant improvement in best-corrected visual acuity. At week 40, one in five patients did not show intra or subretinal fluid, central macular thickness decreased and best-corrected visual acuity was stabilized compared to baseline.

Arg-Leu-Tyr-Glu Suppresses Retinal Endothelial Permeability and Choroidal Neovascularization by Inhibiting the VEGF Receptor 2 Signaling Pathway

Vascular endothelial growth factor (VEGF) plays a pivotal role in pathologic ocular neovascularization and vascular leakage via activation of VEGF receptor 2 (VEGFR2). This study was undertaken to evaluate the therapeutic mechanisms and effects of the tetrapeptide Arg-Leu-Tyr-Glu (RLYE), a VEGFR2 inhibitor, in the development of vascular permeability and choroidal neovascularization (CNV). In cultured human retinal microvascular endothelial cells (HRMECs), treatment with RLYE blocked VEGF-A-induced phosphorylation of VEGFR2, Akt, ERK, and endothelial nitric oxide synthase (eNOS), leading to suppression of VEGF-A-mediated hyper-production of NO. Treatment with RLYE also inhibited VEGF-A-stimulated angiogenic processes (migration, proliferation, and tube formation) and the hyperpermeability of HRMECs, in addition to attenuating VEGF-A-induced angiogenesis and vascular permeability in mice. The anti-vascular permeability activity of RLYE was correlated with enhanced stability and positioning of the junction proteins VE-cadherin, β-catenin, claudin-5, and ZO-1, critical components of the cortical actin ring structure and retinal endothelial barrier, at the boundary between HRMECs stimulated with VEGF-A. Furthermore, intravitreally injected RLYE bound to retinal microvascular endothelium and inhibited laser-induced CNV in mice. These findings suggest that RLYE has potential as a therapeutic drug for the treatment of CNV by preventing VEGFR2-mediated vascular leakage and angiogenesis.

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.

Aflibercept therapy in eyes with neovascular age-related macular degeneration and its effect on choroidal thickness

BACKGROUND

The purpose of this study was to investigate changes in best-corrected visual acuity (BCVA), central macular thickness (CMT) and subfoveal choroidal thickness (SCT) after intravitreal aflibercept injections for neovascular age-related macular degeneration (NV-AMD).

METHODS

Eighty-nine eyes (48 treatment naive, 41 resistant) were included in this prospective study. All patients were treated with three consecutive monthly injections then every two months as required. BCVA, CMT and SCT were recorded and compared within and between the two groups.

RESULTS

The mean increase in BCVA after injections was 0.18 ± 0.34 logMAR in the naive group (p = 0.01) and 0.092 ± 0.38 logMAR in the resistant group (p = 0.131). The mean decrease in CMT was 200.3 ± 216.1 μm in the naive group and 183.3 ± 203.4 μm in the resistant group (p < 0.001 for both). The mean decrease in SCT was 22.1 ± 62.0 μm in the naive group (p = 0.014). The mean change in SCT was 22.28 ± 74.05 μm in the resistant group; this was not statistically significant (p = 0.061).

CONCLUSION

BCVA, CMT and SCT decreased significantly after intravitreal aflibercept injections in naive patients with NV-AMD. Despite anatomic success, functional improvement was not reached and SCT did not significantly decrease after intravitreal aflibercept injections in resistant patients.

Intravitreal conbercept injection for neovascular age-related macular degeneration

AIM

To evaluate the efficacy and safety of intravitreal injection of conbercept in patients with neovascular age-related macular degeneration (AMD).

METHODS

Retrospective review of 66 eyes of 63 patients with neovascular AMD. All patients received 0.5 mg intravitreal injections of conbercept monthly for 3 consecutive months, and then pro re nata treatment was performed. The changes of best-corrected visual acuity (BCVA) and central macular thickness (CMT) were observed before and after treatments. Minimum follow-up time was 12mo. SPSS 22.0 statistical software was used for statistical analysis.

RESULTS

The mean BCVA and CMT of 66 eyes (63 patients) were 1.11±0.60, 533.20±219.95 µm at baseline, and were 0.68±0.38, 310.28±125.60 µm at 3mo. No subjects were lost during the first three months, the improvements were all significantly (P<0.05). During the whole follow-up time of 12mo, 15 subjects (18 eyes) were lost. The mean BCVA and CMT of the rest 48 eyes with the follow-up time at least 1y were 0.83±0.46 and 547.59±196.77 µm at baseline, after 3mo and 12mo of conbercept injections became 0.55±0.41, 318.24±141.29 µm and 0.55±0.51, 333.87±173.25 µm. The differences were significant (P<0.05). No serious complications were observed.

CONCLUSION

Intravitreal injection of conbercept appears to significantly improve visual acuity and anatomical outcomes in patients with neovascular AMD, no serious adverse reactions and complications are observed.

Therapeutic targeting of angiogenesis molecular pathways in angiogenesis-dependent diseases

Angiogenesis is a critical step in the progression of almost all human malignancies and some other life-threatening diseases. Anti-angiogenic therapy is a novel and effective approach for treatment of angiogenesis-dependent diseases such as cancer, diabetic retinopathy, and age-related macular degeneration. In this article, we will review the main strategies developed for anti-angiogenic therapies beside their clinical applications, the major challenges, and the latest advances in the development of anti-angiogenesis-based targeted therapies.

[Site-specific O-Glycosylation Analysis of Therapeutic Fc-fusion Protein by Mass Spectrometry]

Therapeutic Fc-fusion proteins, created by linking bioactive peptides or receptor proteins to the Fc moiety of IgG, are currently being developed. In this development process, a Gly-Gly-Gly-Ser linker (G4S linker) is often used to link the peptide/protein and the Fc portion. O-xylose-type core glycans of glycosaminoglycan are known to attach to the Ser residue on the GSG motif in the G4S linker peptide repeats of the Fc fusion protein produced using the Chinese hamster ovary (CHO) cell expression system. In addition, a recent report demonstrated that unexpected mucin-type O-glycosylations occurred on a peptide in a bioactive peptide-Fc fusion protein; this glycosylation affected the bioactivity of the peptide. Therapeutic proteins with non-natural structures, such as Fc-fusion proteins, undergo unintended O-glycosylations; therefore, it is increasingly important to conduct detailed O-glycosylation analysis of fusion proteins during the developmental stages. In this paper, we have summarized recent reports on the unexpected O-glycosylation in fusion proteins, general O-glycosylation types and sequence motifs, and O-glycosylation analytical techniques involving O-linked oligosaccharide analysis and site-specific O-glycosylation analysis using LC/MS. In addition, we have introduced site-specific O-glycosylation analysis of Fc-fusion proteins with GS linker peptides by LC/MS using higher-energy collisional dissociation-tandem mass spectrometry (HCD-MS/MS) and electron-transfer dissociation (ETD)-MS/MS to obtain preferential dissociation of the peptide moiety in the glycopeptide.

Intravitreal ranibizumab versus laser photocoagulation for retinopathy of prematurity: efficacy, anatomical outcomes and safety

Background/Aims

To compare the efficacy, anatomical outcomes and complications of intravitreal ranibizumab with those of laser photocoagulation for retinopathy of prematurity (ROP).

Methods

This is a retrospective case series of 314 eyes from 165 infants diagnosed with type I ROP and treated with either laser photocoagulation (161 eyes) or intravitreal ranibizumab (0.25 mg/0.025 mL) injection (153 eyes) between January 2006 and December 2016 in a tertiary referral-based hospital. The main outcome was the rate of recurrence requiring additional treatment. Secondary outcomes included the incidence of major complications and final refractive error.

Results

The mean follow-up was 36.3±31.9 months. Recurrences requiring further intervention were noted in 22 (13.7%) laser-treated and 15 (9.8%) ranibizumab-treated eyes (p=0.196). Retinal detachment (8 vs 1, p=0.037) and macular dragging (7 vs 1, p=0.039) were observed in the laser-treated and injection-treated groups, respectively, but no systemic or neurodevelopmental adverse events were reported. In the ranibizumab group, 95.6% showed fully vascularised retinas. Multivariate analyses revealed that birth weight (OR 0.993, p=0.023) and higher ROP stage (OR 11.222, p=0.008) influenced the incidence of major complications.

Conclusion

Intravitreal ranibizumab for ROP appears to achieve similar therapeutic effects than did laser photocoagulation, but with fewer surgical complications such as retinal detachment or macular dragging.

Anti-vascular Endothelial Growth Factor Treatment of Retinopathy of Prematurity: Efficacy, Safety, and Anatomical Outcomes

PURPOSE

To investigate the efficacy, safety, and anatomical outcomes associated with intravitreal anti-vascular endothelial growth factor (VEGF) treatment of retinopathy of prematurity (ROP).

METHODS

We performed a retrospective review of intravitreal anti-VEGF (bevacizumab or ranibizumab) treatment of 153 eyes (83 infants) diagnosed with ROP at two tertiary hospitals from June 2011 to January 2017. The primary outcome was the rate of recurrence requiring additional treatment; secondary outcomes included incidence of major complications and final refractive error.

RESULTS

A total of 101 eyes were treated with bevacizumab, and 52 with ranibizumab. The bevacizumab and ranibizumab groups were characterized by mean birthweights of 941.8 ± 296.1 and 1,257.7 ± 514.5 g, gestational ages at birth of 26.9 ± 1.9 and 28.1 ± 3.2 weeks, and postmenstrual ages at treatment of 40.4 ± 2.4 and 39.2 ± 2.3 weeks, respectively. The two groups differed significantly in birthweights and gestational ages at birth, but not in postmenstrual ages at treatment. The mean follow-up duration was 30.9 ± 18.4 months for the bevacizumab group, and 13.9 ± 12.5 months for ranibizumab. More cases were classified as zone 1 ROP in the ranibizumab group (44.2% vs. 11.9%, p < 0.001). Major surgical interventions included scleral encircling and vitrectomy (one and two eyes, respectively, both in the bevacizumab group). Retinal detachment was noted in one eye treated with bevacizumab. There was no significant difference in the most recent spherical equivalence for the two groups (+0.10 ± 3.66 and +0.22 ± 3.00 diopters for bevacizumab and ranibizumab, respectively). Univariable analysis revealed that only ROP stage influenced the occurrence of major complications (odds ratio, 9.046; p = 0.012).

CONCLUSIONS

Intravitreal anti-VEGF treatment of ROP with both bevacizumab and ranibizumab achieved stable retinal vascularization with a low rate of complications and recurrence. Ranibizumab achieved similar anatomical outcomes as bevacizumab, without additional risk for major complications.