Differential response to intravitreal dexamethasone implant in naïve and previously treated diabetic macular edema eyes

Management of treatment-naïve diabetic macular edema patients: Review of real-world clinical data

The high prevalence of Diabetic macular edema (DME) is a real global health problem. Its complex pathophysiology involves different pathways. Over the last decade, the introduction of intravitreal treatments has dramatically changed the management and prognosis of DME. Among the different treatment options, inhibitors of vascular endothelial growth factor (anti-VEGF) and intravitreal steroids implants represent the first-line therapy of DME. We conducted a review of electronic databases to compile the available evidence about the clinical management of DME in a clinical setting, with a special focus on treatment-naïve patients. Anti-VEGF therapies represent a valuable option for treating DME patients. However, many patients do not respond properly to this treatment and, due to its administration regimen, many patients receive suboptimal treatment in real life. Current evidence demonstrated that in patients with DME, DEX-i improved significantly both anatomic and visual outcomes. Besides eyes with insufficient anti-VEGF respond or recalcitrant DME cases, DEX-i can be effectively and safely used in treatment-naïve DME patients as first line therapy. DEX-i may be considered first line therapy in different clinical scenarios, such as DME eyes with a greater inflammatory component, patients with cardiovascular events, vitrectomized eyes, or those requiring cataract surgery. In conclusion, there are still many points for improvement pending in the clinical management of the patient with DME. Since DME treatment must follow a patient-tailored approach, selecting the best therapeutic approach for each patient requires a good understanding of the pathophysiology of DME.

The Treatment of Diabetic Retinal Edema with Intravitreal Steroids: How and When

Diabetic macular edema (DME) is a common complication of diabetes mellitus and a leading cause of visual impairment worldwide. It is defined as the diabetes-related accumulation of fluid, proteins, and lipids, with retinal thickening, within the macular area. DME affects a significant proportion of individuals with diabetes, with the prevalence increasing with disease duration and severity. It is estimated that approximately 25-30% of diabetic patients will develop DME during their lifetime. Poor glycemic control, hypertension, hyperlipidemia, diabetes duration, and genetic predisposition are recognized as risk factors for the development and progression of DME. Although the exact pathophysiology is still not completely understood, it has been demonstrated that chronic hyperglycemia triggers a cascade of biochemical processes, including increased oxidative stress, inflammation, activation of vascular endothelial growth factor (VEGF), cellular dysfunction, and apoptosis, with breakdown of the blood-retinal barriers and fluid accumulation within the macular area. Early diagnosis and appropriate management of DME are crucial for improving visual outcomes. Although the control of systemic risk factors still remains the most important strategy in DME treatment, intravitreal pharmacotherapy with anti-VEGF molecules or steroids is currently considered the first-line approach in DME patients, whereas macular laser photocoagulation and pars plana vitrectomy may be useful in selected cases. Available intravitreal steroids, including triamcinolone acetonide injections and dexamethasone and fluocinolone acetonide implants, exert their therapeutic effect by reducing inflammation, inhibiting VEGF expression, stabilizing the blood-retinal barrier and thus reducing vascular permeability. They have been demonstrated to be effective in reducing macular edema and improving visual outcomes in DME patients but are associated with a high risk of intraocular pressure elevation and cataract development, so their use requires an accurate patient selection. This manuscript aims to provide a comprehensive overview of the pathology, epidemiology, risk factors, physiopathology, clinical features, treatment mechanisms of actions, treatment options, prognosis, and ongoing clinical studies related to the treatment of DME, with particular consideration of intravitreal steroids therapy.

Influence of prior treatment protocol on intravitreal dexamethasone implant behavior in patients with diabetic macular edema in real-world practice

BACKGROUND AND OBJECTIVE

Intravitreal dexamethasone implant (DEXI) has been placed as an effective option to treat diabetic macular edema (DME). However, there is no consensus on the best time to introduce it. We conducted a study to evaluate anatomical and functional behavior after the first DEXI according to previous treatment.

RESEARCH DESIGN AND METHODS

This retrospective, real-world study between 2013 and 2020 investigated changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT at months 2 and 6 after the first DEXI in DME. Patients were divided into naive, early switch (≤3 anti-VEGF injections), or late switch (>3 anti-VEGF injections) groups.

RESULTS

Among 112 consecutive eyes, mean BCVA and CMT improved significantly in all groups at month 2, with no difference between them. However, this improvement was not maintained at 6 months. The Naíve group presented better BCVA all over the study period. The previously treated groups, which started with worse initial visual acuity, showed more visual gain without reaching the BCVA of the naive group. CMT performance was similar between groups.

CONCLUSIONS

There was similar anatomical and functional behavior in all groups. Poorer visual acuity at baseline was associated with worse functional outcome despite good anatomic response.

Suboptimal outcomes and treatment burden of anti-vascular endothelial growth factor treatment for diabetic macular oedema in phakic patients

OBJECTIVES

In England and Wales, treatment options were limited for patients with diabetic macular oedema (DMO) with phakic eyes that failed anti-vascular endothelial growth factor (anti-VEGF) treatment pre-2022. This study aimed to quantify the response to, and treatment burden of, anti-VEGF treatment in phakic eyes.

METHODS

Retrospective, cohort study using electronic patient record data from two UK centres between 2015 and 2020. Primary objective was proportion of phakic eyes with a suboptimal response after initial 6 months of anti-VEGF treatment. Data were available for 500 eyes from 399 patients.

RESULTS

At 6 months significantly more eyes had a suboptimal response to anti-VEGF treatment: 65.8% (95% CI 61.5-70.0%) vs 34.2% (95% CI 30.0-38.5%), p < 0.0001. Baseline visual acuity (VA) predicted VA outcome, however, despite greater gains in eyes with poorer VA, such eyes did not achieve the same VA levels as those who started treatment with better VA. Only 53.6% of eyes had more than three injections in the first 6 months indicating difficulties in delivering high volume/high frequency treatment. Treatment and review burden were similar over the following years regardless of response to anti-VEGF treatment.

CONCLUSIONS

Data confirm previous real world evidence around response to anti-VEGF treatment, importance of baseline VA and frequency of injections in predicting outcomes in a UK setting. Continuing treatment beyond 6 months in suboptimal responders imposes unnecessary treatment burden without significant change in VA. In suboptimal responders, consideration of early switch to longer acting steroid treatments may help to reduce treatment burden, whilst maintaining or improving vision.

Visual and Anatomical Outcomes of a Single Intravitreal Dexamethasone in Diabetic Macular Edema: An 8 Year Real-World Study

IMPORTANCE

Diabetic macular edema (DME) is a major cause of vision loss in patients with diabetes mellitus. Intravitreal dexamethasone is a treatment option for patients unsuitable for or non-responsive to anti-angiogenic agents.

OBJECTIVE

To quantify visual and anatomical outcomes from an initial intravitreal dexamethasone injection over the expected 6-month period of dexamethasone release by the implant. Design and enrolment: This is a retrospective cohort study using electronic medical records of patients reviewed between 1 January 2012 and 1 April 2022.

SETTING

A tertiary eye-care center in London, United Kingdom; Moorfields Eye Hospital National Healthcare System Foundation Trust.

PARTICIPANTS

The cohort comprised 418 adult patients with DME who received an initial treatment of 700 µg intravitreal dexamethasone in the study period. Of these, 240 patients met the inclusion criteria of ≥2 hospital visits following initial injection (≥1 beyond 6 months) and no previous ocular corticosteroid treatment or missing assessment at baseline.

EXPOSURE(S)

Intravitreal dexamethasone implant (700 µg).

MAIN OUTCOME(S) AND MEASURE(S)

Probability of a positive visual outcome, defined as ≥5 or ≥10 Early Treatment Diabetic Retinopathy Study (ETDRS)-letter gain after treatment when compared to baseline (Kaplan-Meier models).

RESULTS

From the initial intravitreal dexamethasone injection alone, we observed a >75% chance of gaining ≥5 ETDRS letters and >50% chance of gaining ≥10 ETDRS letters within 6 months. There was less than a 50% chance of sustaining either positive visual outcome beyond 4 months.

CONCLUSIONS AND RELEVANCE

Most patients can be expected to have a positive visual outcome following an initial injection of dexamethasone implants that subsides within 4 months. Real-world re-treatment was observed to be delayed until after visual benefits were lost in half of the cohort. Further research will be needed to study the effects of delays in re-treatment.

Healthcare expenditure of intravitreal anti-vascular endothelial growth factor inhibitors compared with dexamethasone implant for diabetic macular oedema

PURPOSE

The aim of this study was to estimate the 1-year costs associated with treating diabetic macular oedema (DME) patients using current intravitreal anti-vascular endothelial growth factor (anti-VEGF) biologics compared with the dexamethasone implant.

METHODS

We conducted a descriptive cost-evaluation analysis using data from Oslo University Hospital and literature to compare three different intravitreal drugs for DME: bevacizumab, aflibercept and dexamethasone. Stratification of patients into 'Naive' or 'Switch' group was based on treatment history. We estimated the costs from healthcare and 'extended' healthcare perspectives. Sensitivity analysis evaluated the impact of various parameters.

RESULTS

The average injections per patient per year for the Naive group (bevacizumab), Switch group (aflibercept) and dexamethasone were 9.5, 9.1 and 3.0 respectively. From a healthcare perspective, the 1-year costs for the Naive group were 15% lower (bevacizumab, €3619), and for the Switch group, 23% higher (aflibercept, €5226) compared with dexamethasone (€4252). The 'extended' healthcare perspective showed the cost per patient per year for bevacizumab remained nominally lower in the Naive group, while dexamethasone remained lower for the Switch group (€5116 for dexamethasone, compared to €4987 for bevacizumab and €6537 for aflibercept).

CONCLUSIONS

From a primary healthcare perspective, the dexamethasone as a first-line DME treatment may increase economic costs in settings where bevacizumab is used off-label. Treating resistant DMEwith dexamethasone may reduce the costs and treatment burden compared with switching to aflibercept.

Dexamethasone Implant for Diabetic Macular Oedema: 1-Year Treatment Outcomes from the Fight Retinal Blindness! Registry

INTRODUCTION

Phase III clinical trials of dexamethasone intravitreal implant for diabetic macular oedema (DMO) have reported significant improvements in visual acuity (VA). Studies evaluating the treatment of DMO in routine clinical practice provide data to identify areas that need improvement. This study evaluated 12-month treatment outcomes of dexamethasone implant for DMO in routine clinical practice.

METHODS

Retrospective data analysis of eyes that started dexamethasone implant for DMO from 1 June 2013 to 30 April 2019 in routine clinical practice tracked in the Fight Retinal Blindness! Registry.

RESULTS

Of the 4282 eyes (2518 patients) that started DMO treatment in the specified period, 267 (6%) eyes (204 patients) received 454 dexamethasone implant injections. Two-fifths (106 eyes) had received prior treatment for DMO. The mean (95% confidence interval [CI]) VA change at 12 months was 1.8 (- 0.5, 4.2) letters from the mean (standard deviation [SD]) VA of 56.5 (19.8) letters at baseline, with 41% eyes achieving at least 20/40. The mean (95% CI) change in central subfield thickness over 1 year was - 79 (- 104, - 54) µm from a mean (SD) of 459 (120) µm at baseline. Eyes that completed 1 year of follow-up received a median (Q1, Q3) of 2 (1, 2) dexamethasone implants. One-tenth of phakic eyes received cataract surgery while 2% had a pressure response requiring anti-glaucoma medications.

CONCLUSIONS

One-year treatment outcomes of dexamethasone intravitreal implant for DMO in routine clinical practice were inferior to those in the clinical trials perhaps because of fewer treatments in clinical practice.

Monoclonal antibodies in diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR), as one of the main complications of diabetes, is among the leading causes of blindness and visual impairment worldwide.

AREAS COVERED

Current clinical therapies include photocoagulation, vitrectomy, and anti-vascular endothelial growth factor (VEGF) therapies. Bevacizumab and ranibizumab are two monoclonal antibodies (mAbs) inhibiting angiogenesis. Intravitreal ranibizumab and bevacizumab can decrease the rate of blindness and retinal thickness, and improve visual acuity whether as monotherapy or combined with other treatments. They can increase the efficacy of other treatments and decrease their adverse events. Although administered intravitreally, they also might enter the circulation and cause systemic effects. This study is aimed to review our current knowledge about mAbs, bevacizumab and ranibizumab, in DR including superiorities, challenges, and limitations. Meanwhile, we tried to shed light on new ideas to overcome these limitations. Our latest search was done in April 2021 mainly through PubMed and Google Scholar. Relevant clinical studies were imported.

EXPERT OPINION

Future direction includes detection of more therapeutic targets considering other components of DR pathophysiology and shared pathogenesis of DR and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, the treat-and-extend regimen, and new ways of drug delivery and other routes of ocular drug administration.

Intravitreal Corticosteroid Implantation in Diabetic Macular Edema: Updated European Consensus Guidance on Monitoring and Managing Intraocular Pressure

Intravitreal therapy for diabetic macular edema can, in susceptible patients, increase intraocular pressure (IOP). As uncontrolled IOP can potentially be sight threatening, monitoring is an essential component of patient management. It can be challenging for retina specialists to ensure that monitoring is rigorous enough to detect and resolve any potential problems at the earliest opportunity without it also being overburdensome for patients who have the lowest risk of developing an IOP rise. We have developed dynamic algorithms that: (1) tailor the frequency and extent of monitoring according to individual susceptibility and current IOP and (2) assist retina specialists in deciding when they should consider a referral to a glaucoma specialist. One algorithm is for patients with a relatively low susceptibility to developing an IOP rise (those whose baseline IOP is < 22 mmHg and who do not have a history of IOP events). Depending on their first post-implantation IOP check, the algorithm classifies them as: low risk if IOP remains < 22 mmHg; medium risk if IOP is 22-25 mmHg and any rise from baseline is < 10 mmHg; or high risk if IOP is > 25 mmHg or any rise from baseline is ≥ 10 mmHg. Thereafter, the algorithm guides on the frequency and extent of monitoring required in each of these groups and, if IOP rises or falls during treatment, patients may move up or down the risk groups accordingly. A different algorithm is provided for patients who are more susceptible to developing an IOP rise (those with a baseline IOP of ≥ 22 mmHg or a prior history of an IOP event). These patients need monitoring more closely so this algorithm has only medium- or high-risk classifications. These algorithms update the previous monitoring guidance by Goñi et al. (Goñi et al. in Ophthalmol Ther 5:47-61, 2016).

Efficacy and safety of single-dose dexamethasone implantation for patients with persistent diabetic macular edema: a systematic review and meta-analysis

PURPOSE

This meta-analysis was conducted to evaluate the efficacy and safety of single-dose dexamethasone implantation for treating persistent DME (diabetic macular edema) refractory to anti-VEGF (anti-vascular endothelial growth factor) drugs over a period of 6 months.

METHODS

All related clinical trials were reviewed by searching electronic databases of PubMed, Medline, Web of Science, Cochrane Library, and EMBASE. The primary outcome parameters were best-corrected visual acuity (BCVA) and central macular thickness (CMT). We performed this meta-analysis by using Stata15.0.

RESULTS

Ten clinical trials involving 362 eyes from 328 patients were eligible in the final analysis. After single-dose dexamethasone implantation, there was a significant improvement in BCVA from baseline to 1, 3, and 6 months with an average increase of - 0.15 logMAR (p < 0.001), - 0.14 logMAR (p < 0.001), and - 0.07 logMAR (p = 0.004), respectively. Further, mean CMT decreased significantly with an average reduction of 249.18 μm (p < 0.001), 217.66 μm (p < 0.001), and 91.56 μm (p < 0.001) at months 1, 3, and 6, respectively.

CONCLUSIONS

Our results indicate that switching to a dexamethasone implant could achieve significant anatomical and functional improvement among patients with refractory DME. Clinicians should be aware of this treatment option in refractory DME.