Ranibizumab monotherapy or combined with laser versus laser monotherapy for diabetic macular edema: a meta-analysis of randomized controlled trials

Substance P Alleviates Retinal Pigment Epithelium Dysfunction Caused by High Glucose-Induced Stress

When the retina is constantly affected by high glucose (HG) due to diabetes, the barrier function of the retinal pigment epithelium (RPE) is impaired, accompanied by unnecessary vascularization. This eventually leads to the development of diabetic retinopathy (DR). This study investigated the recovery effect of substance P (SP) on RPE injured by HG. RPE was treated with HG for 24 h, and HG-induced cellular injuries were confirmed. SP was added to the dysfunctional RPE. Compared to RPE in low glucose (LG) conditions, HG-damaged RPE had large, fibrotic cell shapes, and its cellular viability decreased. HG treatment reduced tight junction protein expression levels and caused oxidative stress by interrupting the antioxidant system; this was followed by inflammatory factor intracellular adhesion molecule-1 (ICAM-1), Monocyte chemotactic protein-1 (MCP-1), and angiogenesis factor vascular endothelial growth factor (VEGF) expression. SP treatment contributed to RPE recovery by enhancing cell viability, tight junction protein expression, and RPE function under HG conditions, possibly by activating the Akt signaling pathway. Importantly, SP treatment reduced ICAM-1, MCP-1, and VEGF expression. Collectively, SP activated survival signals to suppress oxidative stress and improve retinal barrier function in RPE, accompanied by immune suppression. This suggests the possible application of SP to diabetic retinal injuries.

Factors affecting central macular thickness of diabetic macular oedema patients after an induction treatment of intravitreal ranibizumab

OBJECTIVE

Intravitreal ranibizumab is one of the anti-vascular endothelial growth factors used for the treatment of diabetic macular oedema, not always successfully. We aimed to identify the factors affecting the changes of central macular thickness after induction treatment with intravitreal ranibizumab, to predict the treatment effect and facilitate early treatment decisions.

METHODS

Cross-sectional study involving a retrospective record review of diabetic macular oedema patients who received an induction treatment of three monthly 0.5 mg intravitreal ranibizumab injections between 2016 and 2019. Central macular thickness was measured at baseline and 3 months post-treatment. Linear regression was applied to identify the factors associated with the changes of central macular thickness.

RESULTS

A total of 153 diabetic macular oedema patients were involved in this study. Their mean age was 57.5 ± 7.7 years, 54.9% were female. The mean change of central macular thickness from baseline to 3 months after completed induction treatment of intravitreal ranibizumab was 155.5 ± 137.8 μm. Factors significantly associated with changes of central macular thickness were baseline central macular thickness [b = 0.73; 95% (CI): 0.63, 0.84; p = <0.001] and presence of subretinal fluid [b = 35.43; 95% CI: 3.70, 67.16; p = 0.029].

CONCLUSION

Thicker baseline central macular thickness and presence of subretinal fluid were the factors significantly associated with greater changes of central macular thickness in diabetic macular oedema patients after receiving three injections of intravitreal ranibizumab.

Diabetic Retinopathy: An Overview of Treatments

Diabetic retinopathy (DR), substantially impacts the quality of life of diabetic patients, it remains, in developed countries, the leading cause of vision loss in working-age adults (20-65 years). Currently, about 90 million diabetics suffer from DR. DR is a silent complication that in its early stages is asymptomatic. However, over time, chronic hyperglycemia can lead to sensitive retinal damage, leading to fluid accumulation and retinal haemorrhage (HM), resulting in cloudy or blurred vision. It can, therefore, lead to severe visual impairment or even blindness if left untreated. It can be classified into nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). NPDR is featured with intraretinal microvasculature changes and can be further divided into mild, moderate, and severe stages that may associate with diabetic macular oedema (DME). PDR involves the formation and growth of new blood vessels (retinal neovascularisation) under low oxygen conditions. Early identification and treatment are key priorities for reducing the morbidity of diabetic eye disease. In the early stages of DR, a tight control of glycemia, blood pressure, plasma lipids, and regular monitoring can help prevent its progression to more advanced stages. In advanced stages, the main treatments of DR include intraocular injections of anti-vascular endothelial growth factor (VEGF) antibodies, laser treatments, and vitrectomy. The aim of this review is to provide a comprehensive overview of the published literature pertaining to the latest progress in the treatment of DR.

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.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

The Evolving Treatment of Diabetic Retinopathy

Purpose

To review the current therapeutic options for the management of diabetic retinopathy (DR) and diabetic macular edema (DME) and examine the evidence for integration of laser and pharmacotherapy.

Methods

A review of the PubMed database was performed using the search terms diabetic retinopathy, diabetic macular edema, neovascularization, laser photocoagulation, intravitreal injection, vascular endothelial growth factor (VEGF), vitrectomy, pars plana vitreous surgery, antiangiogenic therapy. With additional cross-referencing, this yielded 835 publications of which 301 were selected based on content and relevance.

Results

Many recent studies have evaluated the pharmacological, laser and surgical therapeutic strategies for the treatment and prevention of DR and DME. Several newer diagnostic systems such as optical coherence tomography (OCT), microperimetry, and multifocal electroretinography (mfERG) are also assisting in further refinements in the staging and classification of DR and DME. Pharmacological therapies for both DR and DME include both systemic and ocular agents. Systemic agents that promote intensive glycemic control, control of dyslipidemia and antagonists of the renin-angiotensin system demonstrate beneficial effects for both DR and DME. Ocular therapies include anti-VEGF agents, corticosteroids and nonsteroidal anti-inflammatory drugs. Laser therapy, both as panretinal and focal or grid applications continue to be employed in management of DR and DME. Refinements in laser devices have yielded more tissue-sparing (subthreshold) modes in which many of the benefits of conventional continuous wave (CW) lasers can be obtained without the adverse side effects. Recent attempts to lessen the burden of anti-VEGF injections by integrating laser therapy have met with mixed results. Increasingly, vitreoretinal surgical techniques are employed for less advanced stages of DR and DME. The development and use of smaller gauge instrumentation and advanced anesthesia agents have been associated with a trend toward earlier surgical intervention for diabetic retinopathy. Several novel drug delivery strategies are currently being examined with the goal of decreasing the therapeutic burden of monthly intravitreal injections. These fall into one of the five categories: non-biodegradable polymeric drug delivery systems, biodegradable polymeric drug delivery systems, nanoparticle-based drug delivery systems, ocular injection devices and with sustained release refillable devices. At present, there remains no one single strategy for the management of the particular stages of DR and DME as there are many options that have not been rigorously tested through large, randomized, controlled clinical trials.

Conclusion

Pharmacotherapy, both ocular and systemic, will be the primary mode of intervention in the management of DR and DME in many cases when cost and treatment burden are less constrained. Conventional laser therapy has become a secondary intervention in these instances, but remains a first-line option when cost and treatment burden are more constrained. Results with subthreshold laser appear promising but will require more rigorous study to establish its role as adjunctive therapy. Evidence to support an optimal integration of the various treatment options is lacking. Central to the widespread adoption of any therapeutic regimen for DR and DME is substantiation of safety, efficacy, and cost-effectiveness by a body of sound clinical trials.

Aflibercept with adjuvant micropulsed yellow laser versus aflibercept monotherapy in diabetic macular edema

PURPOSE

To assess the impact of micropulsed laser (MPL) on modifying the number of aflibercept injections when used as an adjuvant therapy in diabetic macular edema (DME).

METHODS

A prospective randomized interventional clinical study included patients with DME attending Al Hadi Clinic, Kuwait, during the period from May 2017 to December 2018. Patients were allocated in two groups; group A received aflibercept injections alone and group B received combined aflibercept injections followed by MPL within a week. The primary outcome was the number of Aflibercept injections in each group guided by the change in central macular thickness (CMT). All the patients were followed for 18 months. Secondary outcome measures included best corrected visual acuity (BCVA), contrast sensitivity (CS), and any recorded complications.

RESULTS

Fifty-four eyes of 51 patients were included (27 in each group). There was no statistically significant difference between the two groups in baseline characteristics except for the age that was statistically higher in group B (p = 0.001). The number of injections were significantly lower in group B (4.1 ± 1.1) than group A (7.3 ± 1.1) (p < 0.005). At 18th month, there was significant reduction in CMT in both groups (p < 0.005) with no statistical difference between the two groups (p = 0.989). Final BCVA in both groups showed statistically significant improvement (p < 0.005) without statistically significant difference between the two groups (p = 0.082). In both groups, the CS showed significant improvement from baseline (p < 0.005). No ocular or systemic adverse effects were observed in either group.

CONCLUSION

Supplemental MPL in eyes with DME may decrease the burden of the aflibercept injection frequency while resulting in comparable anatomical and visual outcomes.

Management of diabetic macular edema patients in clinical practice in Spain

Purpose:

Diabetic macular edema is the main cause of blindness in diabetic patients. Vascular endothelial growth factor is involved in diabetic macular edema pathogenesis. Vascular endothelial growth factor inhibitors are an important option in diabetic macular edema therapy. This survey investigates actual clinical practice in diabetic macular edema in Spain.

Methods:

An expert advisory panel of 17 Spanish ophthalmologists developed a 30-item anonymous questionnaire about diagnosis, treatment, and follow-up in diabetic macular edema. A total of 137 ophthalmologists from 10 Spanish regions completed the questionnaire online.

Results:

Almost all of the respondents (99.3%) record the measured visual acuity and perform biomicroscopic anterior (94.9%) and posterior (91.2%) segment examinations. Similarly, 100% of responding ophthalmologists always/almost always or frequently perform optical coherence tomography. Most respondents (65%) always/almost always or frequently perform a retinography. More than 50% rarely perform fluorescein angiography. Nearly, all (96.4%) of the specialists responded that, in center-involved diabetic macular edema, the first treatment is an anti–vascular endothelial growth factor drug. For corticosteroids, the first choice of most respondents (91.2%) was the dexamethasone implant. In the follow-up, almost all (96.4%) specialists record the measured visual acuity and most also perform biomicroscopic anterior (82.5%) and posterior (83.2%) segment examination.

Conclusion:

This survey shows the actual clinical practice in diabetic macular edema in Spain, finding that anti–vascular endothelial growth factor therapy is frequently used, and that diagnosis, treatments, and follow-up examinations used by specialists are homogeneous and according to diabetic macular edema guidelines.

Aflibercept, bevacizumab or ranibizumab for diabetic macular oedema: recent clinically relevant findings from DRCR.net Protocol T

PURPOSE OF REVIEW

The aim of this study was to provide clinically relevant findings from the DRCR.net Protocol T, a multicentre randomized clinical trial comparing intravitreous aflibercept, repackaged (compounded) bevacizumab and ranibizumab for vision-impairing centre-involved diabetic macular oedema (DME).

RECENT FINDINGS

At 1 year, all three antivascular endothelial growth factor (anti-VEGF) drugs, on average, improved visual acuity. There was no difference among drugs in mean change in visual acuity from baseline among eyes with baseline Snellen equivalent visual acuity of 20/32 to 20/40, whereas aflibercept yielded superior vision outcomes among eyes with baseline visual acuity of 20/50 to 20/320. At 2 years, aflibercept remained superior, on average, to bevacizumab, but not ranibizumab, among eyes with baseline visual acuity of 20/50 to 20/320. Over 2 years, in post-hoc area-under-the-curve analysis, aflibercept vision outcomes were superior to bevacizumab or ranibizumab among these eyes. All three drugs had comparable ocular and systemic safety profiles. The substantial cost differential between aflibercept and bevacizumab raises challenges when safety and efficacy are at odds with cost-effectiveness results.

SUMMARY

When initial visual acuity loss is mild, there are no apparent differences, on average, among aflibercept, bevacizumab and ranibizumab for treating DME. When visual acuity loss is moderate or worse, aflibercept is more likely to improve visual acuity.

Efficiency and safety of laser photocoagulation with or without intravitreal ranibizumab for treatment of diabetic macular edema: a systematic review and Meta-analysis

AIM

To compare the therapeutic effect and safety of laser photocoagulation along with intravitreal ranibizumab (IVR) versus laser therapy in treatment of diabetic macular edema (DME).

METHODS

Pertinent publications were identified through comprehensive searches of PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov to identify randomized clinical trials (RCTs) comparing IVR+laser to laser monotherapy in patients with DME. Therapeutic effect estimates were determined by weighted mean differences (WMD) of change from baseline in best corrected visual acuity (BCVA) and central retinal thickness (CRT) at 6, 12, or 24mo after initial treatment, and the risk ratios (RR) for the proportions of patients with at least 10 letters of improvement or reduction at 12mo. Data regarding major ocular and nonocular adverse events (AEs) were collected and analyzed. The Review Manager 5.3.5 was used.

RESULTS

Six RCTs involving 2069 patients with DME were selected for this Meta-analysis. The results showed that IVR+laser significantly improved BCVA compared with laser at 6mo (WMD: 6.57; 95% CI: 4.37-8.77; P<0.00001), 12mo (WMD: 5.46; 95% CI: 4.35-6.58; P<0.00001), and 24mo (WMD: 3.42; 95% CI: 0.84-5.99; P=0.009) in patients with DME. IVR+laser was superior to laser in reducing CRT at 12mo from baseline with statistical significance (WMD: -63.46; 95% CI: -101.19 to -25.73; P=0.001). The pooled RR results showed that the proportions of patients with at least 10 letters of improvement or reduction were in favor of IVR+laser arms compared with laser (RR: 2.13; 95% CI: 1.77-2.57; P<0.00001 and RR: 0.37; 95% CI: 0.22-0.62; P=0.0002, respectively). As for AEs, the pooled results showed that a significantly higher proportion of patients suffering from conjunctival hemorrhage (study eye) and diabetic retinal edema (fellow eye) in IVR+laser group compared to laser group (RR: 3.29; 95% CI: 1.53-7.09; P=0.002 and RR: 3.02; 95% CI: 1.24-7.32; P=0.01, respectively). The incidence of other ocular and nonocular AEs considered in this Meta-analysis had no statistical difference between IVR+laser and laser alone.

CONCLUSION

The results of our analysis show that IVR+laser has better availability in functional (improving BCVA) and anatomic (reducing CRT) outcomes than laser monotherapy for the treatment of DME. However, the patients who received the treatment of IVR+laser may get a higher risk of suffering from conjunctival hemorrhage (study eye) and diabetic retinal edema (fellow eye).

SUBTHRESHOLD MICROPULSE DIODE LASER VERSUS CONVENTIONAL LASER PHOTOCOAGULATION FOR DIABETIC MACULAR EDEMA: A Meta-Analysis of Randomized Controlled Trials

PURPOSE

To evaluate the relative efficacy of subthreshold micropulse diode laser versus conventional laser photocoagulation for the treatment of diabetic macular edema.

METHODS

A comprehensive literature search was conducted to find relevant randomized controlled trials (RCTs). Efficacy estimates were determined by comparing weighted mean differences of the mean change of best-corrected visual acuity and central macular thickness from baseline.

RESULTS

Six RCTs were selected for this meta-analysis, including 398 eyes (203 eyes in the subthreshold micropulse diode laser group and 195 eyes in the conventional laser group). Subthreshold micropulse diode laser was superior to conventional laser in terms of mean change of logMAR best-corrected visual acuity at 3, 9, and 12 months after treatment (P = 0.02; P = 0.04, and P = 0.03, respectively), and it showed a similar trend at 6 months (P = 0.05). Although, there was no significant difference in terms of mean change in central macular thickness from baseline to 3, 6, 9, or 12 months (P = 0.80; P = 0.20; P = 0.88, and P = 0.86, respectively).

CONCLUSION

Subthreshold micropulse diode laser treatment resulted in better visual acuity compared with conventional laser, although the differences before 12 months are likely to be too small to be of clinical relevance and may be dependent on baseline best-corrected visual acuity. The two types of treatment seem to have similar anatomical outcome.

Combination of Anti-VEGF and Laser Photocoagulation for Diabetic Macular Edema: A Review

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic patients. Thirty years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that focal/grid laser photocoagulation reduces moderate vision loss from DME by 50% or more; thus, macular photocoagulation became the gold standard treatment for DME. However, with the development of anti-VEGF drugs (bevacizumab, ranibizumab, and aflibercept), better outcomes were obtained in terms of visual acuity gain and decrease in macular thickness in some studies when antiangiogenic drugs were administered in monotherapy. Macular laser therapy may still play an important role as an adjuvant treatment because it is able to improve macular thickness outcomes and reduce the number of injections needed. Here, we review some of the clinical trials that have assessed the efficacy of macular laser treatment, either as part of the treatment protocol or as rescue therapy.

Comparison of two individualized treatment regimens with ranibizumab for diabetic macular edema

PURPOSE

To compare outcomes between an as-needed and a treat-and-extend regimen in managing diabetic macular edema with intravitreal ranibizumab.

METHODS

This was a retrospective, single-centre, comparative case series on 46 treatment naive patients with diabetic macular edema. Twenty-two patients were treated following an optical coherence tomography guided treat-and-extend protocol (OCTER), and 24 patients were treated according to a visual acuity guided pro re nata regimen (VAPRN) at a tertiarry referral centre. The main outcome measures were best-corrected visual acuity, central retinal thickness, and the number of ranibizumab injections, as well as visits after 12 months of treatment.

RESULTS

After 12 months, the mean gain in best-corrected visual acuity (± standard deviation) was 8.3 ± 6.7 versus 9.3 ± 8.9 letters in the VAPRN and OCTER group, respectively (p = 0.3). The mean decrease in central retinal thickness was 68.1 ± 88.0 μm in the VAPRN group and 117.6 ± 114.4 μm in the OCTER group (p = 0.2). The mean number of ranibizumab injections was significantly different between the VAPRN (5.9 ± 1.8) and the OCTER protocol (8.9 ± 2.0) (p < 0.001).

CONCLUSION

The visual acuity driven retreatment regimen resulted in a similar visual acuity outcome like optical coherence tomography guided retreatment for diabetic macular edema. Although the number of visits was similar in both groups, patients in the VAPRN group received significantly fewer intravitreal injections than patients in the OCTER group.

[Lack of correlation between retinal variables before treatment and poor functional response after focal photocoagulation in diabetic macular oedema]

BACKGROUND

Although photocoagulation reduces the incidence of moderate visual loss in eyes with focal diabetic macular oedema, some eyes may lose some vision after treatment. The proportion of eyes with poor functional response after photocoagulation, and whether any retinal variable is associated with this, is unknown.

OBJECTIVE

To determine the proportion of eyes with diabetic macular oedema that have a poor functional response after focal photocoagulation, and their associated features.

MATERIAL AND METHODS

A non-experimental, longitudinal, comparative and retrospective study was conducted. The proportion and 95% confidence intervals (CI) of diabetics with macular oedema that had a poor functional response after focal photocoagulation (any visual loss after 6 weeks) were identified. The means of retinal variables before treatment were compared between eyes with and without a poor functional response using the Student t test for independent means.

RESULTS

The study included 115 eyes of patients aged 59.3 (SD 9.24) years. Visual acuity was greater than or equal to 0.5 in 63 eyes (54.8%). A total of 33 eyes had a poor functional response after photocoagulation (28.7%, 95% CI: 13.3 to 44.1). The comparison between retinal variables and visual acuity before treatment did not show any differences between eyes with or without a poor functional response and eyes.

CONCLUSION

Retinal thickening and visual acuity improved or did not change in 71.3% of eyes with diabetic macular oedema with a single photocoagulation procedure. Retinal variables that are usually evaluated were unable to identify the remaining 28.7%, which could lose vision after that treatment, and would require additional interventions.