Using a Novel, Subconjunctival, Sustained-Release Mitomycin C Formulation in a Rabbit Model of Filtration Surgery with Gel Stent Implantation.

Purpose: To investigate gel stent implantation with and without intraoperative sustained-release mitomycin C (MMC SR) in a rabbit model for gel stent implantation, and to examine aqueous humor outflow (AHO) postimplantation. Methods: Four groups of rabbits were included. Group 1 was untreated (control). Groups 2, 3, and 4 received the gel stent without MMC, with MMC solution (subconjunctival injection), and with MMC SR (subconjunctival injection), respectively. Intraocular pressure (IOP) and AHO were assessed via tonometry and indocyanine green-based angiography, respectively. The main efficacy measure was change in IOP from baseline. Results: Following gel stent implantation, Groups 2, 3, and 4 maintained ≥20% IOP reduction (response) for a median duration of 1 week, 6.5 weeks, and 30 weeks, respectively. Angiography showed normal aqueous humor drainage (Group 1) beginning at the perilimbal trabecular plexus and continuing posteriorly to episcleral outflow vessels. Following implantation, drainage occurred preferentially and directly into the subconjunctival bleb. Conclusions: Gel stent implantation with MMC SR was most effective in achieving sustained, long-term IOP reduction in the rabbit model, compared with implantation with or without MMC solution. Bleb presence and the postimplantation aqueous angiography results indicated redirection of the AHO to the subconjunctival vasculature and presumed lymphatics, suggesting efficient glaucoma filtration to lower IOP in this model. This rabbit model and aqueous angiography may help refine understanding of the mechanism of action of minimally invasive glaucoma surgeries and ultimately translate to improved surgical devices and procedures for patients with glaucoma.

Drug Approval for the Treatment of Geographic Atrophy: How We Got Here and Where We Need to Go.

PURPOSE: To discuss the clinical trial results leading to the US Food and Drug Administration (FDA) approval of anti-complement therapies for geographic atrophy (GA), perspectives on functional data from the GA clinical trials, and how lessons from the FDA approval may guide future directions for basic and clinical research in AMD. DESIGN: Selected literature review with analysis and perspective METHODS: We performed a targeted review of publicly available data from the clinical trials of pegcetacoplan and avacincaptad for the treatment of GA, as well as scientific literature on the natural history of GA and the genetics and basic science of complement in AMD. RESULTS: The approval of pegcetacoplan and avacincaptad was based on an anatomic endpoint of a reduction in the rate of GA expansion over time. However, functional data from 2 phase 3 clinical trials for each drug demonstrated no visual benefit to patients in the treatment groups. Review of the genetics of AMD and the basic science of the role for complement in AMD provides only modest support for targeting complement as treatment for GA expansion, and alternative molecular targets for GA treatment are therefore discussed. Reasons for the disconnect between anatomic and functional outcomes in the clinical trials of anti-complement therapies are discussed, providing insight to guide the configuration of future clinical studies for GA. CONCLUSION: Although avacincaptad and pegcetacoplan are our first FDA-approved treatments for GA, results from the clinical trials failed to show any functional improvement after 1 and 2 years, respectively, calling into question whether the drugs represent a "clinically relevant outcome." To improve the chances of more impactful therapies in the future, we provide basic-science rationale for pursuing non-complement targets; emphasize the importance of ongoing clinical research that more closely pins anatomic features of GA to functional outcomes; and provide suggestions for clinical endpoints for future clinical trials on GA.

Faricimab Treat-and-Extend for Diabetic Macular Edema: Two-Year Results from the Randomized Phase 3 YOSEMITE and RHINE Trials.

PURPOSE: To evaluate the 2-year efficacy, durability, and safety of dual angiopoietin-2 and vascular endothelial growth factor (VEGF) A pathway inhibition with intravitreal faricimab according to a personalized treat-and-extend (T&E)-based regimen with up to every-16-week dosing in the YOSEMITE and RHINE (ClinicalTrials.gov identifiers, NCT03622580 and NCT03622593, respectively) phase 3 trials of diabetic macular edema (DME). DESIGN: Randomized, double-masked, noninferiority phase 3 trials. PARTICIPANTS: Adults with visual acuity loss (best-corrected visual acuity [BCVA] of 25-73 letters) due to center-involving DME. METHODS: Patients were randomized 1:1:1 to faricimab 6.0 mg every 8 weeks, faricimab 6.0 mg T&E (previously referred to as personalized treatment interval), or aflibercept 2.0 mg every 8 weeks. The T&E up to every-16-week dosing regimen was based on central subfield thickness (CST) and BCVA change. MAIN OUTCOME MEASURES: Included changes from baseline in BCVA and CST, number of injections, durability, absence of fluid, and safety through week 100. RESULTS: In YOSEMITE and RHINE (n = 940 and 951, respectively), noninferior year 1 visual acuity gains were maintained through year 2; mean BCVA change from baseline at 2 years (weeks 92, 96, and 100 average) with faricimab every 8 weeks (YOSEMITE and RHINE, +10.7 letters and +10.9 letters, respectively) or T&E (+10.7 letters and +10.1 letters, respectively) were comparable with aflibercept every 8 weeks (+11.4 letters and +9.4 letters, respectively). The median number of study drug injections was lower with faricimab T&E (YOSEMITE and RHINE, 10 and 11 injections, respectively) versus faricimab every 8 weeks (15 injections) and aflibercept every 8 weeks (14 injections) across both trials during the entire study. In the faricimab T&E arms, durability was improved further during year 2, with > 60% of patients receiving every-16-week dosing and approximately 80% receiving every-12-week or longer dosing at week 96. Almost 80% of patients who achieved every-16-week dosing at week 52 maintained every-16-week dosing without an interval reduction through week 96. Mean CST reductions were greater (YOSEMITE/RHINE weeks 92/96/100 average: faricimab every 8 weeks -216.0/-202.6 µm, faricimab T&E -204.5/-197.1 µm, aflibercept every 8 weeks -196.3/-185.6 µm), and more patients achieved absence of DME (CST < 325 µm; YOSEMITE/RHINE weeks 92-100: faricimab every 8 weeks 87%-92%/88%-93%, faricimab T&E 78%-86%/85%-88%, aflibercept every 8 weeks 77%-81%/80%-84%) and absence of intraretinal fluid (YOSEMITE/RHINE weeks 92-100: faricimab every 8 weeks 59%-63%/56%-62%, faricimab T&E 43%-48%/45%-52%, aflibercept every 8 weeks 33%-38%/39%-45%) with faricimab every 8 weeks or T&E versus aflibercept every 8 weeks through year 2. Overall, faricimab was well tolerated, with a safety profile comparable with that of aflibercept. CONCLUSIONS: Clinically meaningful visual acuity gains from baseline, anatomic improvements, and extended durability with intravitreal faricimab up to every 16 weeks were maintained through year 2. Faricimab given as a personalized T&E-based dosing regimen supports the role of dual angiopoietin-2 and VEGF-A inhibition to promote vascular stability and to provide durable efficacy for patients with DME. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Investigating the effects of 7-ketocholesterol on retinal pigment epithelium bioenergetics.

Age-related macular degeneration (AMD) is associated with formation of drusen, clusters of lipids, and oxidized lipid products under the retinal pigment epithelium (RPE). 7-Ketocholesterol (7KC) is a form of oxidized cholesterol present in drusen and is hypothesized to play a role in AMD pathogenesis. The association of 7KC with cellular toxicity and inflammation, key elements of AMD pathology, has been demonstrated. However, the effects of 7KC on altering RPE bioenergetics, a potentially important pathologic process in AMD, are unclear. Herein, we describe the effects of non-lethal doses of 7KC on the bioenergetics and phenotype of RPE cells in culture. Metabolic analysis demonstrated a significant dose-dependent increase in total ATP production rates that was driven primarily by an increase in glycolysis. The increase in glycolysis was accompanied by an increase in glucose uptake and increased expression of hexokinase 1. Increased levels of Translocase of Outer Mitochondrial Membrane 20 and NADH:Ubiquinone Oxidoreductase Core Subunit S1, Succinate dehydrogenase, Ubiquinol-Cytochrome C Reductase Core Protein 2, Cytochrome C Oxidase II, and ATP synthase subunit beta, proteins involved in oxidative phosphorylation (OXPHOS), were also seen. However, specific electron transport chain activity remained unchanged. 7KC-treated cells also demonstrated a change in cellular morphology with decreased expression of epithelial markers. In summary, 7KC has significant effects on the bioenergetics and morphology of RPE cells reflective of findings seen in clinical AMD.

Intravitreal Nesvacumab (Anti-Angiopoietin-2) Plus Aflibercept in Neovascular AMD: Phase 2 ONYX Randomized Trial.

Purpose: To compare intravitreal nesvacumab (anti-angiopoietin-2) + aflibercept vs intravitreal aflibercept injection (IAI) in neovascular age-related macular degeneration (nAMD). Methods: Eyes were randomized (1:2:3) to nesvacumab 3 mg + aflibercept 2 mg (LD combo), nesvacumab 6 mg + aflibercept 2 mg (HD combo), or IAI 2 mg at baseline, week 4, and week 8. The LD combo was continued every 8 weeks (q8w). At week 12, the HD combo was re-randomized to q8w or every 12 weeks (q12w) and IAI was re-randomized to q8w, q12w, or HD combo q8w through week 32. Results: The study comprised 365 eyes. At week 12, the mean best-corrected visual acuity (BCVA) gains from baseline were similar in the LD combo group, HD combo group, and IAI group (5.2 letters, 5.6 letters, and 5.4 letters, respectively); the mean central subfield thickness (CST) reductions were similar (182.2 µm, 200.0 µm, and 178.6 µm, respectively). The mean changes in BCVA and CST through week 36 were similar across groups. At week 12, complete retinal fluid resolution was observed in 49.1% (LD combo), 50.8% (HD combo), and 43.6% (IAI) of eyes; the proportions with a CST of 300 µm or less were similar across groups. Numerical trends at week 32 toward complete retinal fluid resolution with combination treatment were not maintained at week 36. Serious ocular adverse events were infrequent and comparable across groups. Conclusions: In nAMD, nesvacumab + aflibercept showed no additional BCVA or CST benefit over IAI monotherapy.

Correlation between hyperreflective foci and visual function testing in eyes with intermediate age-related macular degeneration.

BACKGROUND: To investigate the relationship between intraretinal hyperreflective foci (HRF) and visual function in intermediate age-related macular degeneration (iAMD). METHODS: Retrospective, cross-sectional study. iAMD patients underwent spectral domain optical coherence tomography (SD-OCT) imaging and vision function testing: normal luminance best corrected visual acuity (VA), low luminance VA (LLVA), quantitative contrast sensitivity function (qCSF), low luminance qCSF (LLqCSF), and mesopic microperimetry. Each OCT volume was graded for the presence and number of HRF. Each HRF was graded for: separation from the retinal pigment epithelium (RPE), above drusen, and shadowing. Central drusen volume was calculated by the built-in functionality of the commercial OCT software after manual segmentation of the RPE and Bruch's membrane. RESULTS: HRF group: 11 eyes; 9 patients; mean age 75.7 years. No-HRF group: 11 eyes; 10 patients; mean age 74.8 years. In linear mixed effect model adjusting for cube-root transformed drusen volume, HRF group showed statistically significant worse VA, LLVA, LLqCSF, and microperimetry. HRF group showed worse cone function, as measured by our pre-defined multicomponent endpoint, incorporating LLVA, LLqCSF and microperimetry (p = 0.018). For eyes with HRF, # of HRF did not correlate with any functional measures; however, % of HRF separated from RPE and # of HRF that created shadowing were statistically associated with low luminance deficit (LLD). CONCLUSIONS: The association between the presence of HRF and worse cone visual function supports the hypothesis that eyes with HRF have more advanced disease.

Cross-Sectional Study of Cone Function in Age-Related Macular Degeneration Subjects With Non-foveal Nascent Geographic Atrophy.

PURPOSE: To determine photoreceptor function in subjects with drusen only and non-foveal nascent geographic atrophy (nGA) intermediate age-related macular degeneration. METHODS: In this cross-sectional study, 60 eyes from 33 subjects, 30 with drusen only and 30 with non-foveal nGA determined by spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) underwent testing for best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), and qCSF algorithm (area under log contrast sensitivity function [AULCSF]) under both standard photopic and low-luminance (LL AULCSF) conditions. Areas of nGA-associated hypo-autofluorescence (hypo-AF) were graded. RESULTS: In the drusen group, visual acuity (VA) = 81 letters ± 3 (mean ± SD), LLVA = 65 letters ± 4, AULCSF = 0.99 ± 0.0.5, and LL AULCSF = 0.38 ± 0.04, whereas in the nGA group, VA = 77 ± 4 letters, LLVA = 61± 4, AULCSF = 0.87 ± 0.09, and LL AULCSF = 0.28 ± 0.06. Multivariate analysis of variance among the LLVA, AULCSF, and LL AULCSF did not demonstrate a statistical difference (P = .167), whereas LL AULCSF analyzed by analysis of variance demonstrated a significant difference between the 2 groups (P = .037). Linear regressions demonstrated significant relationships between BCVA and AULCSF in both the drusen and nGA groups (r = 0.83, P < 10-9 and r = 0.61, P = .0004) but did not correlate with AULCSF under low-luminance conditions (r = 2.9, P = .13) in the nGA group. The total area of hypo-AF was negatively associated with poorer visual functions. CONCLUSIONS: The use of LL AULCSF and certain features of FAF should be considered in clinical trials of intermediate age-related macular degeneration. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

A Clinical and Preclinical Assessment of Clinical Trials for Dry Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness for the elderly in high-income countries. Although multivitamin antioxidant nutrients can slow the progression of intermediate "dry" or nonneovascular AMD, no treatment can halt or reverse any stage of dry disease. Multiple biologic pathways have been implicated in AMD pathobiology, including the complement pathway. These pathways have been targeted by various approaches in clinical trials. To date, no treatment has reached their prespecified primary end point in 2 phase III trials, a requirement by the US Food and Drug Administration for a new drug approval. Here, we describe perspectives on the failures and possible successes of various clinical trials that will guide further investigation. These perspectives will also discuss clinical trial design issues to consider in future investigations, and how recent insights into AMD pathobiology might both provide additional explanation for trials not reaching the prespecified primary end points and offer direction for identifying prioritized treatment targets.

YOSEMITE and RHINE: Phase 3 Randomized Clinical Trials of Faricimab for Diabetic Macular Edema: Study Design and Rationale.

Purpose: Faricimab is a novel anti-angiopoietin-2 and anti-vascular endothelial growth factor (VEGF) bispecific antibody with high affinities and specificities for both VEGF and angiopoietin-2. It is postulated that targeting angiogenic factors and inflammatory pathways in addition to the VEGF pathway will increase treatment durability and improve outcomes. The phase 3 YOSEMITE (ClinicalTrials.gov identifier, NCT03622580) and RHINE (ClinicalTrials.gov identifier, NCT03622593) trials are designed to assess efficacy, safety, and durability of faricimab compared with aflibercept in patients with diabetic macular edema (DME). The trials evaluate a personalized treatment interval (PTI) approach to address heterogeneity in treatment response among patients with DME. Design: Two identically designed, global, double-masked, randomized, controlled phase 3 trials (YOSEMITE and RHINE). Participants: Adults with center-involving DME secondary to type 1 or 2 diabetes mellitus. Methods: These studies were designed to evaluate 3 treatment groups: faricimab 6.0 mg dosed either at fixed dosing every 8 weeks after initial treatment with 6 intravitreal doses at 4-week intervals, or faricimab 6.0 mg dosed according to PTI after initial treatment with 4 every-4-week doses, compared with aflibercept 2.0 mg dosed every 8 weeks after 5 initial every-4-week doses. The primary end point of the studies was change from baseline in best-corrected visual acuity at 1 year, averaged over weeks 48, 52, and 56. Secondary end points included anatomic, durability, and patient-reported outcomes. Safety outcomes included incidence and severity of ocular and nonocular adverse events. The PTI is a protocol-defined flexible regimen based on the treat-and-extend concept, which allowed up to every-16-week adjustable dosing based on objective and standardized criteria. The PTI design aimed to maximize therapeutic results while minimizing treatment burden. Main Outcome Measures: We describe the rationale for the study design and the novel PTI (up to every-16-week adjustable dosing) approach for treatment with faricimab. Results: YOSEMITE and RHINE enrolled 940 and 951 patients, respectively. Results from each study will be reported separately. Conclusions: YOSEMITE and RHINE were the first registrational trials in retinal disease to incorporate an objective PTI regimen, allowing for up to every-16-week adjustable dosing with a dual angiopoietin-2 and VEGF-A inhibitor, faricimab 6.0 mg, for treatment of DME.

INTRAVITREAL NESVACUMAB (ANTIANGIOPOIETIN 2) PLUS AFLIBERCEPT IN DIABETIC MACULAR EDEMA: Phase 2 RUBY Randomized Trial.

PURPOSE: The purpose of this study was to compare intravitreal nesvacumab (anti-angiopoietin 2) plus aflibercept with intravitreal aflibercept injection (IAI) in diabetic macular edema. METHODS: The eyes (n = 302) were randomized (1:2:3) to nesvacumab 3 mg + aflibercept 2 mg (LD combo), nesvacumab 6 mg + aflibercept 2 mg (HD combo), or IAI 2 mg at baseline, Weeks 4 and 8. LD combo continued every 8 weeks (q8w). HD combo was rerandomized at Week 12 to q8w or every 12 weeks (q12w); IAI to q8w, q12w, or HD combo q8w through Week 32. RESULTS: Week 12 best-corrected visual acuity gains for LD and HD combo versus IAI were 6.8, 8.5, and 8.8 letters; Week 36 changes were similar. Central subfield retinal thickness reductions at Week 12 were -169.4, -184.0, and -174.6 µm (nominal P = 0.0183, HD combo vs. IAI); Week 36 reductions for LD combo and HD combo q8w and q12w versus IAI were -210.4, -223.4, and -193.7 versus -61.9 µm (nominal P < 0.05). At Week 12, 13.3% and 21.3% versus 15.2% had ≥2-step Diabetic Retinopathy Severity Scale improvement (LD and HD combos vs. IAI) and 59.6% and 66.3% versus 53.7% had complete foveal center fluid resolution. Safety was comparable across groups. CONCLUSION: Nesvacumab + aflibercept demonstrated no additional visual benefit over IAI. Anatomic improvements with HD combo may warrant further investigation.

ANATOMIC AND FUNCTIONAL IMPROVEMENT OF A DRUSENOID PIGMENT EPITHELIAL DETACHMENT: A CASE REPORT.

BACKGROUND/PURPOSE: Age-related macular degeneration is the most prevalent cause of permanent vision loss in the developed world. Drusenoid pigment epithelial detachments are a biomarker of age-related macular degeneration disease progression and typically result in poor visual prognosis. Low luminance visual acuity (LLVA) has been previously been shown to correlate with the severity of age-related macular degeneration. However, the degree of spontaneous improvement of this functional outcome is still under investigation. METHODS: Observational clinical case report. RESULTS: A drusenoid pigment epithelial detachment that increased in size with the development of hyperreflective foci spontaneously improved with restoration of normal foveal contour over the span of 41 months without progression to geographic atrophy or choroidal neovascularization. Although best-corrected visual acuity remained stable both before and after the pigment epithelial detachment resolution, low luminance visual acuity decreased from a baseline of 59 (20/63 -1) to 39 (20/160 -1) letters over 17 months. However, over the subsequent 24 months, low luminance visual acuity improved by 35 letters to 74 letters (20/32 -2). CONCLUSION: Drusenoid pigment epithelial detachments can resolve without treatment. Low luminance visual acuity seems to correlate with the anatomic improvement and can improve spontaneously by more than six lines of vision.

Normal- and Low-Luminance Automated Quantitative Contrast Sensitivity Assessment in Eyes With Age-Related Macular Degeneration.

PURPOSE: To assess the effectiveness of an active learning approach to measuring the contrast sensitivity function (CSF) in patients with various degrees of dry age-related macular degeneration (AMD) under multiple luminance conditions. DESIGN: Cross-sectional study. METHODS: Patients with AMD (26 intermediate AMD, 19 AMD with subretinal drusenoid deposits [SDD], 20 geographic atrophy [GA]) and 23 age-matched controls were tested with the Manifold Contrast Vision Meter (Adaptive Sensory Technology) and the qCSF algorithm, which applies active learning to estimate a model of the CSF's global shape. Testing was performed under conditions of standard and low luminance. For each AMD severity, the area under log CSF (AULCSF) and contrast sensitivities at individual spatial frequencies were calculated for analysis. Low-luminance deficits (LLDs) for visual acuity (VA) and AULCSF were calculated as the difference between standard and low luminance values. RESULTS: Progressive decreases in AULCSF were observed as disease severity increased. For standard luminance, pairwise comparisons revealed significant differences between control/intermediate AMD (P < .0005), control/SDD (P < .0005), control/GA (P < .0005), and intermediate AMD/GA (P < .005). Similarly, for low luminance, pairwise comparisons revealed significant differences between the controls and each disease group (all P < .0005), in addition to significant differences between intermediate AMD/SDD (P < .005), and intermediate AMD/GA (P < .005). No correlations were found between LLD VA and LLD AULCSF in any AMD groups. CONCLUSIONS: Contrast sensitivity measured via qCSF under both standard- and low-luminance conditions correlates with advancing stages of dry AMD. The interaction between luminance and contrast sensitivity appears to reflect a different aspect of visual function than the interaction between luminance and VA.

C5 Inhibitor Avacincaptad Pegol for Geographic Atrophy Due to Age-Related Macular Degeneration: A Randomized Pivotal Phase 2/3 Trial.

PURPOSE: The complement pathway may play a key role in the pathogenesis of age-related macular degeneration (AMD). The safety and efficacy of avacincaptad pegol (Zimura, IVERIC bio Inc, New York, NY), a C5 inhibitor, were assessed in participants with geographic atrophy (GA) secondary to AMD (GATHER1 Study). DESIGN: International, prospective, randomized, double-masked, sham-controlled, pivotal phase 2/3 clinical trial. PARTICIPANTS: A total of 286 participants with GA secondary to AMD. MAIN OUTCOME MEASURES: The primary efficacy endpoint was the mean rate of change in GA over 12 months measured by fundus autofluorescence (FAF) at 3 timepoints: baseline, month 6, and month 12. RESULTS: The reduction in the mean rate of GA growth (square root transformation) over 12 months was 27.4% (P = 0.0072) for the avacincaptad pegol 2 mg cohort and 27.8% (P = 0.0051) for the avacincaptad pegol 4 mg cohort compared with their corresponding sham cohorts. The results for both dose groups were statistically significant. Avacincaptad pegol was generally well tolerated after monthly administration over 12 months. There were no avacincaptad pegol-related adverse events (AEs) or inflammation. Further, there were no ocular serious AEs (SAEs) and no cases of endophthalmitis. The most frequent ocular AEs were related to the injection procedure. CONCLUSIONS: Intravitreal administration of avacincaptad pegol 2 mg and 4 mg led to a significant reduction of GA growth in eyes with AMD over a 12-month period. Because C5 inhibition theoretically preserves C3 activity, it may offer additional safety advantages. A second confirmatory pivotal clinical trial is underway to confirm the efficacy and safety of avacincaptad pegol in slowing the GA growth (GATHER2 Study).

THE ANGIOPOIETIN/TIE PATHWAY IN RETINAL VASCULAR DISEASES: A Review.

PURPOSE: To provide a concise overview for ophthalmologists and practicing retina specialists of available clinical evidence of manipulating the angiopoietin/tyrosine kinase with immunoglobulin-like and endothelial growth factor-like domains (Tie) pathway and its potential as a therapeutic target in retinal vascular diseases. METHODS: A literature search for articles on the angiopoietin/Tie pathway and molecules targeting this pathway that have reached Phase 2 or 3 trials was undertaken on PubMed, Association for Research in Vision and Ophthalmology meeting abstracts (2014-2019), and ClinicalTrials.gov databases. Additional information on identified pipeline drugs was obtained from publicly available information on company websites. RESULTS: The PubMed and Association for Research in Vision and Ophthalmology meeting abstract search yielded 462 results, of which 251 publications not relevant to the scope of the review were excluded. Of the 141 trials related to the angiopoietin/Tie pathway on ClinicalTrials.gov, seven trials focusing on diseases covered in this review were selected. Vision/anatomic outcomes from key clinical trials on molecules targeting the angiopoietin/Tie pathway in patients with retinal vascular diseases are discussed. CONCLUSION: Initial clinical evidence suggests a potential benefit of targeting the angiopoietin/Tie pathway and vascular endothelial growth factor-A over anti-vascular endothelial growth factor-A monotherapy alone, in part due to of the synergistic nature of the pathways.