Effectiveness of the Dexamethasone Intravitreal Implant for Treatment of Patients with Diabetic Macular Oedema

Switching to subtenon triamcinolone acetonide does not jeopardize the functional and anatomic outcomes of dexamethasone implant treated eyes with diabetic macular edema

BACKGROUND

Intraocular dexamethasone implant (DEXi) is an efficient treatment for diabetic macular edema (DME). However, it may be unavailable or contraindicated. Triamcinolone acetonide is another corticosteroid that has proved to be safe and effective in treating macular edema complicating various diseases including diabetes. The purpose of this study is to evaluate the outcomes of a switch from DEXi to subtenon triamcinolone acetonide (STTA) and back, in eyes with DME.

METHODS

Retrospective study. DME eyes that had been treated with DEXi and switched to STTA between October 2018 and February 2019 (stock shortage of DEXi) were included. The functional and anatomical outcomes of the switch and switch-back were studied.

RESULTS

26 eyes of 17 patients (mean age 67.1 ± 8.2 years) were considered. The mean baseline visual acuity (VA) was 0.35 ± 0.17 decimals remaining stable after DEXi, STTA and switch-back to DEXi. The mean central macular thickness (CMT) was 492.7 ± 32.8 µm initially, decreasing to 294.3 ± 133.4 µm after DEXi, 369.9 ± 182.3 µm after STTA and 297.6 ± 72.0 µm after switching back to DEXi (all p < 0.05 versus baseline). Compared to baseline, the CMT reduction was numerically better after DEXi and switching back to DEXi than after STTA (mean reduction: -200.4 µm, -167.7 µm, and -95.08 µm respectively, p = 0.13). Intraocular pressure was comparable after DEXi and STTA.

CONCLUSION

DEXi is the steroid of choice in DME. However, STTA can be a cost-effective alternative when DEXi is unavailable or contraindicated. This study suggests that STTA may be used in the context of a step therapy in DME.

Vitreous inflammatory and angiogenic factors on patients with proliferative diabetic retinopathy or diabetic macular edema: the role of Lipocalin2

PURPOSE

Quantitative analysis of vitreous inflammatory and angiogenic factors from patients with proliferative diabetic retinopathy (PDR) or diabetic macular edema (DME).

MATERIALS AND METHODS

Collection of undiluted vitreous samples from 20 diabetic patients: 13 with proliferative diabetic retinopathy (PDR) and 7 with diabetic macular edema (DME). DME patients had suboptimal response to anti-VEGF treatment. Samples from 11 control patients, with vitreomacular interface pathology such as idiopathic epiretinal membrane (iERM) (n = 4), vitreomacular traction syndrome (VMT) (n = 3) and full thickness macular hole (FTMH) (n = 3), were also collected. The levels of IL1b, IL6, IL8, IL27, TNFα, ICAM-1, VCAM, MCP-1, VEGFA and LCN2 were measured using cytometry flow analysis. Median values were compared with Mann-Whitney test since the distributions were skewed. Statistical analysis was performed with the Statistical Package for Social Sciences software (IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.).

RESULTS

The median concentration of LCN2, IL6, IL8, IL1b, IL27, ICAM, VCAM-1, MCP-1, TNFa and VEGFA was higher in PDR patients than in controls. Similarly, the median concentration of LCN2, IL6, IL8, IL27, ICAM, VCAM-1, TNFa and VEGFA was higher in DME patients than in controls. In particular, median LCN2 concentration in diabetic patients was 5,711 pg/ml (interquartile range [IR] = 2,534), while in controls was 2,586 pg/ml (IR = 2,345). Moreover, median LCN2 was 6,534 pg/ml in the DME group (IR = 6,850) and 4,785 pg/ml in the PDR group (IR = 2,608), (p = 0.025).

CONCLUSION

Various inflammatory and angiogenic factors are involved in the pathophysiology of PDR and DME. Elevated vitreous levels of LCN2 in PDR and especially in DME patients reveal a potential pathogenic association. More extended studies could verify LCN2 as an alternative therapeutic target.

Topical drug delivery to the retina: obstacles and routes to success

INTRODUCTION

Retinal diseases are one of the main reasons for vision loss where all available drug treatments are based on invasive drug administration such as intravitreal injections. Despite huge efforts and some promising results in animal models, almost all delivery technologies tested have failed in human trials. There are however examples of clinically effective topical delivery systems such as fast dissolving aqueous eye drop suspensions.

AREAS COVERED

Six obstacles to topical drug delivery to the eye have been identified and discussed in some details. These obstacles consist of static membrane barriers to drug permeation into the eye, dynamic barriers such as the lacrimal drainage and physiochemical barriers such as low thermodynamic activity. It is explained how and why these obstacles hamper drug permeation and how different technologies, both those that are applied in marketed drug products and those that are under investigation, have addressed these obstacles.

EXPERT OPINION

The reason that most topical drug delivery systems have failed to deliver therapeutic drug concentrations to the retina is that they do not address physiochemical barriers such as the thermodynamic activity of the permeating drug molecules. Topical drug delivery to the retina has only been successful when the static, dynamic, and physiochemical barriers are addressed simultaneously.

Guidelines for the Management of Center-Involving Diabetic Macular Edema: Treatment Options and Patient Monitorization

Diabetic macular edema (DME) is the main cause of visual impairment associated with diabetic retinopathy (DR) and macular laser, during approximately three decades, and was the single treatment option. More recently, intravitreous injections of anti-angiogenics and corticosteroids modified the treatment paradigm associated with significant vision improvements. Nevertheless, not all patients respond satisfactorily to anti-VEGF or corticosteroid injections, so an adequate treatment choice and a prompt switch in therapeutic class is recommended. Several algorithms and guidelines have been proposed for treating center involving DME to improve patients’ vision and quality of life. However, in Portugal, such guidelines are lacking. The present review aimed to provide guidelines for the treatment options and patient monitorization in the management of center-involving DME. We recommend anti-vascular endothelial growth factor (VEGF) as first-line therapy after a clinical evaluation accompanied by a rigorous metabolic control. Depending on the response obtained after 3–6 monthly intravitreal injections we suggest switching outside the class in case of a non-responder, maintaining the anti-VEGF-therapy in responders to anti-angiogenics. The treatment regimen for Dexamethasone intravitreal implant (DEXii) should be pro-re-nata with bi-monthly or quarterly monitoring visits (with a scheduled visit at 6–8 weeks after DEXii for intraocular pressure control). If a patient does not respond to DEXii, switch again to anti-VEGF therapy, combine therapies, or re-evaluate patients diagnose. There is a resilient need to understand the disease, its treatments, regimens available, and convenience for all involved to propose an adequate algorithm for the treatment of diabetic retinopathy (DR) and DME in an individualized regimen. Further understanding of the contributing factors to the development and progression of DR should bring new drug discoveries for more effective and better-tolerated treatments.

The effects of intravitreal triamcinolone acetonide in diabetic macular edema refractory to anti-VEGF treatment

PURPOSE

To investigate the efficacy and safety of primary intravitreal triamcinolone acetonide (IVTA) in eyes affected by diabetic macular edema (DME) refractory to anti-vascular endothelial growth factor (VEGF) therapy.

STUDY DESIGN

Retrospective observational study METHODS: The medical records of patients who attended our clinic from March 2013 to September 2018 with refractory macular were reviewed. We included the patients who were injected at least one IVTA and completed 6 months of observation. Best-corrected Snellen visual acuity (VA), central macular thickness (CMT), intraocular pressure (IOP), and adverse events (AEs) were examined at baseline and at 1 month, 2 months, 3 months, and 6 months.

RESULTS

Sixty-four eyes of 54 subjects were included. The mean VA was improved significantly at all time points compared to pre-treatment (P < 0.0001), with the greatest mean improvement at 1 month (0.3 logMAR). The reduction in mean CMT was also significant at all follow-up examinations compared to baseline (P < 0.0001), with the greatest decrease at 1 month (113.68 ± 53.78 μm). A poorer VA before injection was a factor that influenced visual gain 1 month post treatment (0.247 logMAR units/unit increase in baseline VA, P = 0.006). The most common AE associated with IVTA treatment was elevated IOP (11 eyes), observed significantly more often after IVTA injections containing a preservative (25.8%) than after those that were preservative-free (9.1%) (P = 0.033).

CONCLUSION

IVTA injection can be an alternative steroid treatment for DME refractory to anti-VEGF therapy.