Intravitreal bevacizumab injection alone or combined with triamcinolone versus macular photocoagulation in bilateral diabetic macular edema; application of bivariate generalized linear mixed model with asymmetric random effects in a subgroup of a clinical trial

Comparing the efficacy of glucocorticoids and anti-VEGF in treating diabetic macular edema: systematic review and comprehensive analysis

Introduction

The aim of this study was to better understand the efficacy of various drugs, such as glucocorticoids and anti-vascular endothelial growth factors (VEGF), in the treatment of diabetic macular edema (DME), and to evaluate various clinical treatment regimens consisting of different therapeutic measures.

Methods

This study included randomized controlled trials up to February 2023 comparing the efficacy of corticosteroid-related therapy and anti-VEGF therapy. PubMed, the Cochrane Library, and Embase were searched, and the quality of the studies was carefully assessed. Finally, 39 studies were included.

Results

Results at 3-month followup showed that intravitreal injection of bevacizumab (IVB) + triamcinolone acetonide (TA) was the most beneficial in improving best-corrected visual acuity and reducing the thickness of macular edema in the center of the retina in patients with DME. Results at 6-month follow-up showed that intravitreal dexamethasone (DEX) was the most effective in improving patients' bestcorrected visual acuity and reducing the thickness of central macular edema.

Discussion

Overall, IVB+TA was beneficial in improving best-corrected visual acuity and reducing central macular edema thickness over a 3-month follow-up period, while DEX implants had a better therapeutic effect than anti-VEGF agents at 6 months, especially the patients with severe macular edema and visual acuity impaired.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=397100, identifier CRD42023397100.

Therapeutic effect of simultaneous intravitreal dexamethasone and aflibercept on diabetic macular edema

AIMS

To report the effect of simultaneous intravitreal dexamethasone (DEX) and aflibercept for the treatment of diabetic macular edema (DME).

METHODS

This retrospective analysis of an open-label, multicenter, consecutive case series included 102 eyes of 81 patients with DME. Patients were selected into two groups. The control group consisted of 50 eyes treated with aflibercept alone, and the combination group consisted of 52 eyes treated with simultaneous DEX implant and aflibercept injection. The primary endpoints were changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline to month 6. The secondary endpoint was the interval of retreatment.

RESULTS

Baseline BCVA increased and CRT decreased at 6 months in both groups. Pseudophakic eyes in the combination group exhibited significantly greater BCVA improvement compared with phakic eyes (p = 0.031). Fewer intravitreal treatments were required for eyes treated with combination therapy than for those treated with aflibercept alone (1.56 ± 0.54 vs. 4.04 ± 1.26, p < .0001), with a mean retreatment interval of 3.66 ± 0.69 months.

CONCLUSIONS

Simultaneous intravitreal DEX and aflibercept achieved non-inferior improvement of visual and anatomic outcomes compared with aflibercept alone for DME, but exhibited a significantly longer treatment interval and superior visual outcome in pseudophakic eyes. This therapeutic approach is considered a valid strategy for treating DME in the era of COVID-19.

Managing Diabetic Macular Edema in Clinical Practice: Systematic Review and Meta-Analysis of Current Strategies and Treatment Options

Purpose

This meta-analysis aims to summarize 12-month best-corrected visual acuity (BCVA) outcomes in response to anti-vascular endothelial growth factor (VEGF) therapy and dexamethasone implant for the treatment of diabetic macular edema (DME) and to identify factors affecting treatment response using evidence generated from meta-regression.

Methods

A systematic review of electronic databases was conducted to identify randomized controlled trials (RCTs) and real-life/observational studies that reported 12-month changes in BCVA in patients with DME on anti-VEGF or dexamethasone implant treatment in monotherapy. Study factors that were analyzed are baseline patient characteristics, study type, drug employed, number of injections and 12-month change in BCVA. Data were pooled in a random-effects meta-analysis with BCVA change as the main outcome. Meta-regression was conducted to assess the impact of multiple covariates.

Results

One-hundred-five heterogeneous study populations (45,032 eyes) were identified and included in the analysis. The use of anti-VEGFs and dexamethasone implant induced an overall increase of +8.13 ETDRS letters in BCVA at 12 months of follow-up. Meta-regression provided evidence that mean BCVA change using anti-VEGFs was not statistically higher for RCTs (p=0.35) compared to observational studies. Dexamethasone implant showed a trend for better results in observational studies over RCTs. Populations following a fixed aflibercept regimen performed better than those following a reactive treatment regimen. Mean BCVA gain was higher in younger populations (p<0.001), with lower baseline BCVA (p<0.0001) and longer diabetes duration (p<0.0001), receiving a higher number of injections (p<0.0001).

Conclusion

Intravitreal therapy with anti-VEGFs or dexamethasone implant produces a significant improvement in BCVA at 12 months in patients with DME. Meta-regression identified the modifiable covariates that can be targeted in order to maximize functional results.

Anti-vascular endothelial growth factor combined with intravitreal steroids for diabetic macular oedema

BACKGROUND

The combination of steroid and anti-vascular endothelial growth factor (VEGF) intravitreal therapeutic agents could potentially have synergistic effects for treating diabetic macular oedema (DMO). On the one hand, if combined treatment is more effective than monotherapy, there would be significant implications for improving patient outcomes. Conversely, if there is no added benefit of combination therapy, then people could be potentially exposed to unnecessary local or systemic side effects.

OBJECTIVES

To assess the effects of intravitreal agents that block vascular endothelial growth factor activity (anti-VEGF agents) plus intravitreal steroids versus monotherapy with macular laser, intravitreal steroids or intravitreal anti-VEGF agents for managing DMO.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 1); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the ICTRP. The date of the search was 21 February 2018.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of intravitreal anti-VEGF combined with intravitreal steroids versus intravitreal anti-VEGF alone, intravitreal steroids alone or macular laser alone for managing DMO. We included people with DMO of all ages and both sexes. We also included trials where both eyes from one participant received different treatments.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane.Two authors independently reviewed all the titles and abstracts identified from the electronic and manual searches against the inclusion criteria. Our primary outcome was change in best corrected visual acuity (BCVA) between baseline and one year. Secondary outcomes included change in central macular thickness (CMT), economic data and quality of life. We considered adverse effects including intraocular inflammation, raised intraocular pressure (IOP) and development of cataract.

MAIN RESULTS

There were eight RCTs (703 participants, 817 eyes) that met our inclusion criteria with only three studies reporting outcomes at one year. The studies took place in Iran (3), USA (2), Brazil (1), Czech Republic (1) and South Korea (1). Seven studies used the unlicensed anti-VEGF agent bevacizumab and one study used licensed ranibizumab. The study that used licensed ranibizumab had a unique design compared with the other studies in that included eyes had persisting DMO after anti-VEGF monotherapy and received three monthly doses of ranibizumab prior to allocation. The anti-VEGF agent was combined with intravitreal triamcinolone in six studies and with an intravitreal dexamethasone implant in two studies. The comparator group was anti-VEGF alone in all studies; two studies had an additional steroid monotherapy arm, another study had an additional macular laser photocoagulation arm. Whilst we judged these studies to be at low risk of bias for most domains, at least one domain was at unclear risk in all studies.When comparing anti-VEGF/steroid with anti-VEGF monotherapy as primary therapy for DMO, we found no meaningful clinical difference in change in BCVA (mean difference (MD) -2.29 visual acuity (VA) letters, 95% confidence interval (CI) -6.03 to 1.45; 3 RCTs; 188 eyes; low-certainty evidence) or change in CMT (MD 0.20 μm, 95% CI -37.14 to 37.53; 3 RCTs; 188 eyes; low-certainty evidence) at one year. There was very low-certainty evidence on intraocular inflammation from 8 studies, with one event in the anti-VEGF/steroid group (313 eyes) and two events in the anti-VEGF group (322 eyes). There was a greater risk of raised IOP (Peto odds ratio (OR) 8.13, 95% CI 4.67 to 14.16; 635 eyes; 8 RCTs; moderate-certainty evidence) and development of cataract (Peto OR 7.49, 95% CI 2.87 to 19.60; 635 eyes; 8 RCTs; moderate-certainty evidence) in eyes receiving anti-VEGF/steroid compared with anti-VEGF monotherapy. There was low-certainty evidence from one study of an increased risk of systemic adverse events in the anti-VEGF/steroid group compared with the anti-VEGF alone group (Peto OR 1.32, 95% CI 0.61 to 2.86; 103 eyes).One study compared anti-VEGF/steroid versus macular laser therapy. At one year investigators did not report a meaningful difference between the groups in change in BCVA (MD 4.00 VA letters 95% CI -2.70 to 10.70; 80 eyes; low-certainty evidence) or change in CMT (MD -16.00 μm, 95% CI -68.93 to 36.93; 80 eyes; low-certainty evidence). There was very low-certainty evidence suggesting an increased risk of cataract in the anti-VEGF/steroid group compared with the macular laser group (Peto OR 4.58, 95% 0.99 to 21.10, 100 eyes) and an increased risk of elevated IOP in the anti-VEGF/steroid group compared with the macular laser group (Peto OR 9.49, 95% CI 2.86 to 31.51; 100 eyes).One study provided very low-certainty evidence comparing anti-VEGF/steroid versus steroid monotherapy at one year. There was no evidence of a meaningful difference in BCVA between treatments at one year (MD 0 VA letters, 95% CI -6.1 to 6.1, low-certainty evidence). Likewise, there was no meaningful difference in the mean CMT at one year (MD - 9 μm, 95% CI -39.87μm to 21.87μm between the anti-VEGF/steroid group and the steroid group. There was very low-certainty evidence on raised IOP at one year comparing the anti-VEGF/steroid versus steroid groups (Peto OR 0.75, 95% CI 0.16 to 3.55).No included study reported impact of treatment on patients' quality of life or economic data. None of the studies reported any cases of endophthalmitis.

AUTHORS' CONCLUSIONS

Combination of intravitreal anti-VEGF plus intravitreal steroids does not appear to offer additional visual benefit compared with monotherapy for DMO; at present the evidence for this is of low-certainty. There was an increased rate of cataract development and raised intraocular pressure in eyes treated with anti-VEGF plus steroid versus anti-VEGF alone. Patients were exposed to potential side effects of both these agents without reported additional benefit. The majority of the evidence comes from studies of bevacizumab and triamcinolone used as primary therapy for DMO. There is limited evidence from studies using licensed intravitreal anti-VEGF agents plus licensed intravitreal steroid implants with at least one year follow-up. It is not known whether treatment response is different in eyes that are phakic and pseudophakic at baseline.

The Role of Plasma Kallikrein-Kinin Pathway in the Development of Diabetic Retinopathy: Pathophysiology and Therapeutic Approaches

Diabetic retinal disease is characterized by a series of retinal microvascular changes and increases in retinal vascular permeability that lead to development of diabetic retinopathy (DR) and diabetic macular edema (DME), respectively. Current treatment strategies for DR and DME are mostly limited to vascular endothelial growth factor (VEGF) inhibitors and laser photocoagulation. These treatment modalities are not universally effective in all patients, and potential side effects persist in a significant portion of patients. The plasma kallikrein-kinin system (KKS) is one of the pathways that has been identified in the vitreous in proliferative DR and DME. Preclinical studies have shown that the activation of intraocular KKS induces retinal vascular permeability, vasodilation, and retinal thickening. Proteomic analysis from vitreous of eyes with DME has shown that KKS and VEGF pathways are potentially independent biologic pathways. Furthermore, proteins associated with DME in the vitreous were significantly more correlated with the KKS pathway compared to VEGF pathway. Preclinical experiments on diabetic animals showed that inhibition of KKS components was found to be an effective approach to decrease retinal vascular permeability. An initial phase I human trial of a novel plasma kallikrein inhibitor for the treatment of DME is currently ongoing to test the safety of this approach and serves as an initial step in the translation of basic science discovery into an innovative clinical intervention.