Meta-analysis and review on the effect of bevacizumab in diabetic macular edema

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.

Current Treatments and Innovations in Diabetic Retinopathy and Diabetic Macular Edema

Diabetic retinopathy (DR) is one of the leading causes of blindness worldwide. Multiple treatment options have been used over time to attempt to modify the natural progression of the disease in both proliferative diabetic retinopathy (PDR) and diabetic macular edema (DME). These two retinal complications are the result of microvascular occlusions and vascular hyperpermeability and are considered one of the leading causes of irreversible blindness in patients of working age. It is now well demonstrated that PDR and DME are associated with increased levels of inflammatory and pro-angiogenic factors in the ocular compartment. To date, laser photocoagulation, vascular endothelial growth factor (VEGF) inhibitors, and corticosteroids have demonstrated efficacy in their treatment in large randomized controlled trials and in real-life observational studies. This manuscript aims to provide a comprehensive review of current treatments, including the main drugs used in diabetic pathologic manifestations, as well as new therapeutic alternatives, such as extended-release intraocular devices.

Combined phacoemulsification surgery and intravitreal triamcinolone injection versus stand-alone surgery in patients with type 2 diabetes: a prospective randomized trial

Background

We would assess the efficacy of intravitreal injection of triamcinolone acetonide IVTA combined with standard phacoemulsification on the central subfield macular thickness (CSMT), the progression of diabetic retinopathy (DR), and the corrected distant visual acuity (CDVA) in type 2 diabetic patients.

Methods

In this prospective single-blinded randomized clinical trial we recruited patients with type 2 diabetes who were eligible for cataract surgery. The patients were randomly assigned to two groups. The case group received an intravitreal IVTA at the end of phacoemulsification, and the control group had routine surgery. CSMT, progression of DR, CDVA, IOP, and adverse events including endophthalmitis were compared between the groups preoperatively and at 1, 3, and 6 months postoperatively.

Results

Among a total of 66 patients that were treated within the study period, 50 patients were included in the final analysis. The case group comprised 21 eyes, and the control group included 29 eyes. Regression models and corrected ANOVA test for repeated measures showed a significant reduction in CSMT at 3 and 6 months postoperatively, which was most significant when the preoperative CSMT was ≥300 μm, with a cut-off value of 347.3 μm in the case group (p < 0.000). DR progression was halted in the case group at 6 months with 52.38% of patients having their DR classified as moderate (P = 0.012). CDVA was significantly improved from baseline 6/60 (logMAR 1.0) pre-op to 6/6 (logMAR 0.00) at 6 months post-op in the case group, and from baseline 6/120 (logMAR 1.3) pre-op to 6/12 (logMAR 0.3) at 6 months post-op in the control group. The gain in visual acuity was significantly higher in the case group at all study points (p < 0.001). No significant rise in IOP was observed at any study point in both groups (p = 0.23 > 0.05). No endophthalmitis was recorded.

Conclusions

Diabetic patients benefit significantly from cataract surgery. This study supports IVTA injection at the end of phacoemulsification in diabetic patients. Triamcinolone is an affordable (which is of particular importance in low-income countries as per our setting), and relatively safe “phaco-enhancer”.

Trial registration

NCT05413330. Initial release 10/06/2022. Unique Protocol ID: UDMS-Opthal-01-2022.

[Impact of the SARS-CoV-2 pandemic on diabetic macular edema and prognostic factors]

But

Décrire le retentissement sur l’acuité visuelle et l’épaisseur centromaculaire après arrêt des injections intravitréennes d’anti-VEGF chez les patients diabétiques marocains au cours de la pandémie du Coronavirus. Et étudier les facteurs pouvant être associés à l’aggravation.

Matériel et méthodes

Cette étude transversale monocentrique a inclus les patients programmés pour injections intravitréennes de Bevacizumab au cours de la période du confinement (20 mars 2020–20 mai 2020) et qui n’en ont pas bénéficié. Ont été recueillis : l’âge, le sexe, l’ancienneté du diabète, le nombre d’injections reçues avant le confinement, l’acuité visuelle en pré-confinement et post-confinement ainsi que l’épaisseur centromaculaire pré-confinement et post-confinement.

Résultats

Cent cinquante quatre yeux de 104 patients ont été analysés. 57,8 % étaient des hommes avec une moyenne d’âge de 59,4 ± 9,04 ans. La durée moyenne d’arrêt des injections intravitréennes est de 57,3 ± 6,7 jours. Le nombre moyen d’injections intravitréennes de Bevacizumab reçues avant le confinement a été estimé à 2,29 ± 2,1. L’aggravation de l’acuité visuelle a été notée chez 44,8 % de nos patients. Les facteurs associés à l’aggravation fonctionnelle sont le faible nombre d’injections intravitréennes de Bevacizumab reçues avant le confinement (p = 0,001) ainsi que le déséquilibre diabétique (p = 0,04). L’aggravation structurelle a été constatée chez 26,6 % des patients et elle était associée au faible nombre d’injections réalisées avant le confinement (p = 0,038).

Conclusion

Le report des injections intravitréennes au cours du confinement a eu des effets négatifs sur l’acuité visuelle et l’épaisseur centromaculaire des yeux avec OMD. Un report prolongé des injections intravitréennes d’anti-VEGF chez les patients diabétiques doit être évité.

Topical ketorolac as an adjunctive treatment with intravitreal bevacizumab in the management of diabetic macular edema: A double-masked placebo-controlled randomized clinical trial

PURPOSE

To evaluate the additional effect of ketorolac eye drops on therapeutic effects of intravitreal Bevacizumab in patients with diabetic macular edema (DME) METHODS: In a randomized clinical trial, 50 patients with center involved DME (macular thickness ≥ 300 microns accompanied by decreased VA (24 < BCVA ≤ 70 ETDRS letters) were enrolled consecutively and randomized 1:1 to receive either bevacizumab plus topical ketorolac (25 patients) or bevacizumab plus artificial tears (25 patients). Patients with proliferative diabetic retinopathy, history of intraocular surgery, intravitreal injection in less than three months, macular photocoagulation less than 6 months and any other concomitant ocular pathologies were excluded from the study. All the patients received three consecutive monthly injections of intravitreal bevacizumab (IVB). After that, patients were examined every 6 weeks and reinjection was administered based on the "as needed" protocol if macular thickness was 300 microns or more and VA was 70 ETDRS letters or less.. Patients also received either topical ketorolac or artificial tears three times a day over the study period (6 months). Changes in central subfield thickness (CST), best-corrected visual acuity (BCVA, ETDRS letters), and number of IVB injections were compared between the study groups.

RESULTS

Fifty eyes of 50 patients were included (25 eyes in each group). Mean CST was significantly decreased in both study groups at 14^th week (-87 ± 98 µm, P = 0.012 and -100 ± 147 µm, P = 0.006 in bevacizumab plus ketorolac and bevacizumab plus artificial tears groups, respectively). Nevertheless, the changes of mean CST remained significant only in bevacizumab plus ketorolac group up to 26^th week (-147 ± 124 µm, P < 0.001 and -51 ± 145 µm, P = 0.245, respectively). Comparing two groups, reduction of mean CST from baseline was significantly greater in bevacizumab plus ketorolac group compared with the control group at 26^th week. (difference = -97 µm, 95%CI = -182 to -11, P = 0.017). In the study group, mean BCVA significantly increased at both 20^th week (6.2 ± 10.1, P = 0.04) and 26^th week (8.2 ± 10.9, P = 0.03). In contrast, visual acuity did not significantly improve at any time points in bevacizumab plus artificial tears group, While insignificant, the 26-week mean change of visual acuity from baseline was greater in bevacizumab plus ketorolac group (difference = 6.5 ETDRS letter; 95%CI = -14.4 to 1.4) Two groups were comparable regarding number of IVB injections (P = 0.99).

CONCLUSION

Topical ketorolac 0.5% three times a day could enhance and sustain the efficacy of intravitreal bevacizumab in the treatment of DME.

MEASUREMENTS OF RETINAL FLUID BY OPTICAL COHERENCE TOMOGRAPHY LEAKAGE IN DIABETIC MACULAR EDEMA: A Biomarker of Visual Acuity Response to Treatment

PURPOSE

To evaluate the effects of anti-vascular endothelial growth factor treatment on retinal fluid in patients with diabetic macular edema by using optical coherence tomography leakage (OCT-L), a new method of quantifying sites of lower than normal optical reflectivity (LOR) in OCT, and to correlate these findings with best-corrected visual acuity (BCVA) response.

METHODS

Prospective analysis of 21 eyes with diabetic macular edema, naive to anti-vascular endothelial growth factor treatment. Macular cube 512 × 128 and OCT angiography 6 × 6-mm scans (CIRRUS AngioPlex; ZEISS, Dublin, CA) were acquired in all eyes before the first ranibizumab injection (V1) and 1 week after treatment (V2). Optical coherence tomography leakage analysis was performed with Angioplex raw scan data used to calculate LOR map ratios. Lower optical reflectivity ratios at baseline and differences from V1 to V2 and other OCT morphological features such as central retinal thickness measurements, disorganization of the inner retinal layers, and disruption of ellipsoid zone were compared with BCVA response 1 month after the first intravitreal injection.

RESULTS

After the first intravitreal injection of ranibizumab, eight patients (38%) were identified as good responders, 5 (24%) as moderate, and 8 (38%) as poor. There were no significant BCVA differences at baseline. Significant differences were found in LOR ratio changes between the different treatment response groups after 1 week of treatment, especially in outer segment and outer plexiform layer (outer segment-good responders: -53%, responders: -12%, and poor responders: 7% [P = 0.026]; outer plexiform layer-good responders: -49%, responders: 18%, and poor responders: 5% [P = 0.010]). Lower optical reflectivity ratios differences after 1 week of treatment predict better the BCVA treatment response at 1 month than changes of central retinal thickness, disorganization of the inner retinal layer, and ellipsoid zone disruption, especially in the outer segment and outer plexiform layer (area under the curve = 0.82 and 0.73, respectively).

CONCLUSION

Optical coherence tomography leakage changes after anti-vascular endothelial growth factor treatment of diabetic macular edema, identifying the degree of decrease in retinal fluid in the outer layers of the retina is a more robust biomarker of BCVA recovery than central retinal thickness, disorganization of the inner retinal layer, or ellipsoid zone disruption changes.

Update on pharmacotherapy for ocular surface squamous neoplasia

The most frequently encountered non-pigmented tumor of the ocular surface is ocular surface squamous neoplasia (OSSN). Over the past two decades, the pharmacological management of OSSN has grown, with topical 5-fluorouracil, mitomycin, and interferon alpha 2b all being successfully used to treat this disease. Other agents, such as anti-vascular endothelial growth factor (VEGF), retinoic acid, cidofovir and Aloe vera, have less frequently been used in the treatment of OSSN. This review will discuss these pharmacologic agents, summarizing available data and presenting the approach to the treatment of these tumors.

Optical coherence tomography findings predictive of response to treatment in diabetic macular edema

Objective

To evaluate the short-term efficacy of intravitreal bevacizumab (IVB) and posterior sub-tenon triamcinolone injections (PSTI) on the basis of spectral-domain optical coherence tomography (SD-OCT) patterns in diabetic macular edema (DME).

Methods

We retrospectively reviewed 73 eyes of 73 patients with DME. Based on the presence of serous retinal detachment (SRD), eyes were categorized into two groups, and either IVB or PSTI treatment was performed. Central macular thickness (CMT) and the degree of SRD were assessed preoperatively and 1 month postoperatively. The severity of intraretinal edema was approximated based on the distance from the external limiting membrane to the internal limiting membrane.

Results

In eyes with SRD, reduction of SRD was greater with IVB than with PSTI. Moreover, reduction of intraretinal edema was greater with PSTI than with IVB. In eyes without SRD, PSTI achieved greater CMT reduction, compared with IVB.

Conclusions

In DME patients with SRD, IVB achieved greater reduction of SRD, compared with PSTI; however, intraretinal edema responded more favorably to PSTI, regardless of the presence of SRD. Our results suggest that the classification of DME based on OCT findings may be useful to predict responses to IVB or PSTI treatments.

OPTICAL COHERENCE TOMOGRAPHY BASELINE PREDICTORS FOR INITIAL BEST-CORRECTED VISUAL ACUITY RESPONSE TO INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR TREATMENT IN EYES WITH DIABETIC MACULAR EDEMA: The CHARTRES Study

PURPOSE

To identify baseline optical coherence tomography morphologic characteristics predicting the visual response to anti-vascular endothelial growth factor therapy in diabetic macular edema.

METHODS

Sixty-seven patients with diabetic macular edema completed a prospective, observational study (NCT01947881-CHARTRES). All patients received monthly intravitreal injections of Lucentis for 3 months followed by PRN treatment and underwent best-corrected visual acuity measurements and spectral domain optical coherence tomography at Baseline, Months 1, 2, 3, and 6. Visual treatment response was characterized as good (≥10 letters), moderate (5-10 letters), and poor (<5 or letters loss). Spectral domain optical coherence tomography images were graded before and after treatment by a certified Reading Center.

RESULTS

One month after loading dose, 26 patients (38.80%) were identified as good responders, 19 (28.35%) as Moderate and 22 (32.83%) as poor responders. There were no significant best-corrected visual acuity and central retinal thickness differences at baseline (P = 0.176; P = 0.573, respectively). Ellipsoid zone disruption and disorganization of retinal inner layers were good predictors for treatment response, representing a significant risk for poor visual recovery to anti-vascular endothelial growth factor therapy (odds ratio = 10.96; P < 0.001 for ellipsoid zone disruption and odds ratio = 7.05; P = 0.034 for disorganization of retinal inner layers).

CONCLUSION

Damage of ellipsoid zone, higher values of disorganization of retinal inner layers, and central retinal thickness decrease are good predictors of best-corrected visual acuity response to anti-vascular endothelial growth factor therapy.

Aflibercept for clinically significant diabetic macular edema: 12-month results in daily clinical practice

Purpose

To assess the effectiveness and safety of intravitreal aflibercept in clinically significant diabetic macular edema (DME) in daily clinical practice.

Methods

Prospective, open-label, single-center study. Anti-vascular endothelial growth factor naïve patients with clinically significant DME received intravitreal injections of aflibercept 2 mg, five monthly doses followed by a fixed schedule every 2 months for 12 months. The mean change in best-corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS] letters) was the primary outcome.

Results

The mean BCVA improved significantly as compared with baseline at 12 months of treatment (47.3 [14.2] vs 62.2 [13.9] ETDRS letters, P<0.001). Significant improvement in BCVA was already observed at visit 2 after the loading doses of aflibercept. At 12 months, gains in ETDRS letters were documented in all eyes (100%), with gains ≥10 letters in 89.6%, ≥15 letters in 65.5%, and ≥20 letters in 6.9% (n=2). A significant reduction in central macular thickness from a mean of 460.5 (11.8) μm at baseline to 229.0 (43.8) μm at 12 months (P<0.001) was observed. Significant reductions of central macular thickness were already observed after the loading doses and continued lowering throughout the study period. No adverse events occurred.

Conclusion

Aflibercept as a first-line therapy was effective and well tolerated for treating clinically significant DME in naïve patients in daily practice. Successful results in terms of improvement of visual and reduction in central macular thickness contribute to provide evidence for the positioning of aflibercept as a first-line indication of newly diagnosed clinically significant DME.

Intravitreal bevacizumab and dexamethasone implant for treatment of chronic diabetic macular edema

OBJECTIVE

To evaluate anatomical and functional outcomes of intraviteal bevacizumab (IVB) in patients with chronic diabetic macular edema (DME), and the effectivity and safety of dexamethasone implant in those unresponsive to regular IVB treatment.

METHODS

Thirty-five eyes of 35 patients (16 male and 19 female) with chronic DME (central foveal thickness (CFT)  > 275 μm, duration  > 6 months) received three injections of 2.5 mg IVB with six-week intervals. At 18 weeks, dexamethasone implant was applied to patients unresponsive to IVB. Main outcomes were the change in best corrected visual acuity (BCVA), CFT and ocular and systemic adverse effects for both drugs. The patients responsive to IVB were followed up for 36 weeks and those patients receiving dexamethasone implant were followed up for 24 weeks postoperatively.

RESULTS

At 18 weeks, the mean BCVA (0.68 ± 0.40 logMAR, p = 0.45) and CFT (453 ± 169 μm, p = 0.58) did not show any significant change compared to baseline (0.74 ± 0.42 logMAR and 521 ± 151 μm, respectively). In 20 patients (%57.1) responsive to IVB, the CFT was significantly improved from 12 to 36 weeks with the mean value of 295 ± 42 μ (p = 0.01). However, no significant difference was observed for BCVA during this period (p = 0.17). Dexamethasone was implanted in 15 eyes (42.8%) unresponsive to IVB at 18 weeks. Statistically significant improvements were observed in BCVA (at postoperative 4 and 12 weeks) and CFT (at postoperative 4, 12 and 24 weeks). In addition, both parameters significantly worsened at 24 weeks compared to 12 weeks (p < 0.001 and p = 0.01, respectively).

CONCLUSIONS

Patients with chronic DME should be followed in accordance with a fixed treatment protocol combining anti-VEGF and steroid treatments.

[Effectiveness of diffuse diabetic macular edema treatment in relation to structural changes in macular region]

AIM

to describe baseline functional and anatomical parameters of the macular region and how they change under ranibizumab therapy depending on the type of diabetic macular edema (DME) determined with optical coherence tomography (OCT).

MATERIAL AND METHODS

The study included 100 patients (100 eyes) with diabetes mellitus and DME (38 men and 62 women) aged 61.9±5.6 years with the mean disease duration of 8.48 years. Basing on OCT findings, 4 groups (25 patients each) were formed: sponge-like DME, cystoid DME, DME with serous neuroepithelium detachment (NED), and mixed DME (cystoid DME and serous NED). All patients received 3 consecutive monthly injections of 0.5 mg ranibizumab. The relationship between anatomical, functional, and clinical parameters was analyzed.

RESULTS

The lowest visual acuity (VA) at baseline was found in patients with mixed DME (р<0.05). The greatest increase in VA after the 3 injections was noted in patients with sponge-like DME - 0.34±0.18. Retinal thickness was significantly lower (р<0.05) in sponge-like DME as compared to other groups both at baseline and after the treatment. Foveolar thickness decreased after the treatment in all groups, the effect being the most pronounced (the edema got reduced by 42.4%, р<0.05) in cystoid DME. The most significant reduction in macular volume (by 2.7 mm3) as well as its lowest absolute post-treatment values were reported for patients with cystoid edema (9.01 mm3, р<0.05 as compared to sponge-like and mixed DME). Correlation analysis revealed an evident relationship between the improvement in VA (ΔVA) and the decrease in macular volume (р<0.05). Of clinical parameters, only diabetes duration correlated with the extent of VA improvement (r=-0.3; p<0.05).

CONCLUSION

The effectiveness of intravitreal ranibizumab therapy for diffuse DME depends on the morphological type of macular edema by OCT. Moreover, it correlates with diabetes duration.

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population

PURPOSE

To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population.

METHODS

Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9.

RESULTS

Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence.

CONCLUSION

This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

The effect of intravitreal bevacizumab and ranibizumab on macular edema of the contralateral eye: A comparative study of two anti-VEGFs

Purpose:

To compare the effects of bevacizumab and ranibizumab on the visual function and macular thickness in the contralateral (untreated) eye of patients with bilateral diabetic macular edema (DME).

Materials and Methods:

Thirty-nine patients with bilateral DME, who had been treated with both bevacizumab and ranibizumab in the same eye, were considered retrospectively for this study. Recorded outcome measurements included the best-corrected visual acuity (BCVA) assessment with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and the central subfield macular thickness (CSMT) measurement of the contralateral, uninjected eye before and at 4 weeks after the injections.

Results:

The median BCVA of the uninjected eye was 50 ETDRS letters and the median CSMT was 459 μm preceding the bevacizumab injection whereas at the control appointment, 4 weeks after the injection, the median BCVA had increased to 52 letters (P = 0.098), and the median CSMT had decreased to 390 μm (P = 0.036). The mean interval between the bevacizumab and ranibizumab treatments was 4.79 ΁ 1.52 months. The measurements of the untreated eye after the ranibizumab treatment showed that the median BCVA decreased from 55 to 52 letters, and the median CSMT increased from 361 μm to 418 μm (P = 0.148 and P = 0.109, respectively).

Conclusions:

In contrast to ranibizumab, the intravitreal administration of bevacizumab resulted in a statistically significant decrease in macular thickness in the untreated eye in patients with bilateral DME.

Intravitreal bevacizumab for diabetic macular oedema: 5-year results of the Pan-American Collaborative Retina Study group

BACKGROUND/AIMS

To report the long-term anatomical and functional outcomes of patients with centre-involved diabetic macular oedema (DME) treated with intravitreal bevacizumab (IVB).

METHODS

Retrospective case series. Patients diagnosed with centre-involved DME that were treated with at least one injection of 1.25 mg IVB and had a minimum follow-up of 60 months. Patients underwent measurement of best-corrected visual acuity (BCVA), ophthalmoscopy, optical coherence tomography and fluorescein angiography at baseline, 6-month, 12-month, 24-month, 36-month, 48-month and 60-month visits. The paired samples t test was used to compare the central macular thickness (CMT) and BCVA with baseline values. Statistical significance was indicated by p<0.05.

RESULTS

Two hundred and one consecutive patients (296 eyes) were included. The mean number of IVB injections per eye was 8.4±7.1 (range: 1-47 injections). At 5 years, the BCVA remained stable at 20/100 (logarithm of the minimum angle of resolution=0.7±0.4). Eighty-six (29%) eyes improved ≥2 lines of BCVA, 129 (43.6%) eyes remained stable and 81 (27.4%) eyes lost ≥2 lines of BCVA at 60 months. Mean CMT decreased from 403.5±142.2 μm at baseline to 313.7±117.7 μm over 5 years follow-up (p≤0.0001).

CONCLUSIONS

The early visual gains due to IVB were not maintained 5 years after treatment.

Clinical biomarkers and molecular basis for optimized treatment of diabetic retinopathy: current status and future prospects

Diabetic retinopathy is a highly specific microvascular complication of diabetes and a leading cause of blindness worldwide. It is triggered by hyperglycemia which causes increased oxidative stress leading to an adaptive inflammatory assault to the neuroretinal tissue and microvasculature. Prolonged hyperglycemia causes increased polyol pathway flux, increased formation of advanced glycation end-products, abnormal activation of signaling cascades such as activation of protein kinase C (PKC) pathway, increased hexosamine pathway flux, and peripheral nerve damage. All these changes lead to increased oxidative stress and inflammatory assault to the retina resulting in structural and functional changes. In addition, neuroretinal alterations affect diabetes progression. The most effective way to manage diabetic retinopathy is by primary prevention such as hyperglycemia control. While the current mainstay for the management of severe and proliferative diabetic retinopathy is laser photocoagulation, its role is diminishing with the development of newer drugs including corticosteroids, antioxidants, and antiangiogenic and anti-VEGF agents which work as an adjunct to laser therapy or independently. The current pharmacotherapy of diabetic retinopathy is incomplete as a sole treatment option in view of limited efficacy and short-term effect. There is a definite clinical need to develop new pharmacological therapies for diabetic retinopathy, particularly ones which would be effective through the oral route and help recover lost vision. The increasing understanding of the mechanisms of diabetic retinopathy and its biomarkers is likely to help generate better and more effective medications.

Anti-VEGF Therapy and the Retina: An Update

Ocular angiogenesis and macular oedema are major causes of sight loss across the world. Aberrant neovascularisation, which may arise secondary to numerous disease processes, can result in reduced vision as a result of oedema, haemorrhage, and scarring. The development of antivascular endothelial growth factor (anti-VEGF) agents has revolutionised the treatment of retinal vasogenic conditions. These drugs are now commonly employed for the treatment of a plethora of ocular pathologies including choroidal neovascularisation, diabetic macular oedema, and retinal vein occlusion to name a few. In this paper, we will explore the current use of anti-VEGF in a variety of retinal diseases and the impact that these medications have had on visual outcome for patients.

Complications of intravitreal injections in patients with diabetes

Intravitreal injections for the treatment of retinal disorders and intraocular infection have become a common ophthalmic procedure, and injections of anti-vascular endothelial growth factor agents or steroids are frequently performed for the treatment of diabetic macular edema or other diabetic vascular pathology. Diabetic patients may be at higher risk of adverse events than non-diabetic individuals given frequent systemic co-morbidities, such as cardiovascular and renal disease, susceptibility to infection, and unique ocular pathology that includes fibrovascular proliferation. Fortunately, many associated complications, including endophthalmitis, are related to the injection procedure and can therefore be circumvented by careful attention to injection techniques. This review highlights the safety profile of intravitreal injections in patients with diabetes. Although diabetic patients may theoretically be at higher risk than non-diabetic patients for complications, a comprehensive review of the literature does not demonstrate substantial increased risk of intravitreal injections in patients with diabetes.

Comparative Effectiveness of Intravitreal Bevacizumab With or Without Triamcinolone Acetonide for Treatment of Diabetic Macular Edema

Background: Bevacizumab and triamcinolone acetonide (TA) are both common choices for treatment of diabetic macular edema (DME), but the comparative efficacy of combined or separate applications is still not determined. Objectives: To compare the treatment efficacy of intravitreal bevacizumab (IVB) and the combination of IVB and intravitreal triamcinolone (IVT) for DME patients. Methods: PubMed, EMBASE, and the Cochrane library were systematically reviewed for randomized controlled trials comparing IVB with IVB/IVT. Data on visual acuity (VA) and central macular thickness (CMT) changes at 3 and 6 months were extracted and data on adverse events were collected. A meta-analysis was performed using the software RevMan 5.3. The methodological quality and bias risks were also evaluated. Results: VA improved more significantly in the IVB/IVT group compared with the IVB group at 3 months (mean difference [MD] = 0.07; 95% CI = 0.01 to 0.13), whereas there was no significant difference at 6 months (MD = −0.01; 95%CI = −0.11 to 0.09). The CMT reduction in the IVB/IVT group was significantly greater than that in the IVB group at 3 months (MD = 48.40; 95%CI = 30.23 to 66.57), but no statistically significant difference was found at 6 months (MD = 0.47; 95%CI = −24.11 to 25.04). Ocular hypertension was detected in 9/243 eyes in the IVB/IVT group but none of the IVB eyes. Conclusion: IVB/IVT is more effective for improving VA and decreasing CMT at 3 months in DME. A single injection of TA along with the first IVB could improve outcome within 3 months, but this is not sustained at 6 months. Continuous IVT/IVB treatment should be performed in further trials to clarify its long-term potential efficacy.

The effect of combined treatment of bevacizumab and triamcinolone for diabetic macular edema refractory to previous intravitreal mono-injections

The purpose of this study is to evaluate the efficiency of combined treatment of bevacizumab and triamcinolone in refractory diffuse DME (DDME). Twenty-five pseudophakic eyes with DDME refractory to previous successive intravitreal bevacizumab (IVB, 1.25 and 2.5 mg/0.1 ml) and triamcinolone (IVT, 4 mg and 10 mg/0.1 ml) injections were included. The average number of injections was two (1-4). The mean best corrected visual acuity (BCVA) was 0.8 (0.3-1.5) logMAR before enrollment, 0.6 (0.0-1.5) logMAR at 6 months and 0.6 (0-1.8) logMAR at 12 months (p = 0.0001, p = 0.003). The median central macular thickness (CMT) of all the eyes was 575 (502-1049) µm at baseline, 370 (179-983) µm at 6 months, and 410 (198-929) µm at 12 months (p = 0.0001; p = 0.0001). At 6 months, the VA of 13 (52 %) patients was stabilized (± 0.2 logMAR of initial BCVA) and 12 (48 %) patients showed visual improvement (>0.2 logMAR). At 12 months, 10 (40 %) patients had stabilized vision, 13 (52 %) showed visual improvement and 2 (8 %) showed visual loss. At 6 months, 18 (72 %) patients showed anatomic stabilization (a decrease of 10 % to 50 % in initial CMT) and 7 (28 %) anatomical success (a decrease in CMT more than 50 % or ≤250 µm at final visit). At 12 months, 13 (52 %) patients showed anatomic stabilization, 10 (40 %) anatomic success, and 2 (8 %) anatomical failure (decrease in CMT less than 10 %). The combined application of IVB and triamcinolone may improve vision and decrease CMT in severe DDME cases refractory to previous monotherapies.

Anti-vascular endothelial growth factor for diabetic macular oedema

BACKGROUND

Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy. Although grid or focal laser photocoagulation has been shown to reduce the risk of visual loss in DMO, or clinically significant macular oedema (CSMO), vision is rarely improved. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) modalities is used to try to improve vision in people with DMO.

OBJECTIVES

To investigate the effects in preserving and improving vision and acceptability, including the safety, compliance with therapy and quality of life, of antiangiogenic therapy with anti-VEGF modalities for the treatment of DMO.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2014), EMBASE (January 1980 to April 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to April 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 April 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing any antiangiogenic drugs with an anti-VEGF mechanism of action versus another treatment, sham treatment or no treatment in people with DMO.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. The risk ratios (RR) for visual loss and visual gain of three or more lines of logMAR visual acuity were estimated at one year of follow-up (plus or minus six months) after treatment initiation.

MAIN RESULTS

Eighteen studies provided data on four comparisons of interest in this review. Participants in the trials had central DMO and moderate vision loss.Compared with grid laser photocoagulation, people treated with antiangiogenic therapy were more likely to gain 3 or more lines of vision at one year (RR 3.6, 95% confidence interval (CI) 2.7 to 4.8, 10 studies, 1333 cases, high quality evidence) and less likely to lose 3 or more lines of vision (RR 0.11, 95% CI 0.05 to 0.24, 7 studies, 1086 cases, high quality evidence). In meta-analyses, no significant subgroup difference was demonstrated between bevacizumab, ranibizumab and aflibercept for the two primary outcomes, but there was little power to detect a difference. The quality of the evidence was judged to be high, because the effect was large, precisely measured and did not vary across studies, although some studies were at high or unclear risk of bias for one or more domains. Regarding absolute benefit, we estimated that 8 out of 100 participants with DMO may gain 3 or more lines of visual acuity using photocoagulation whereas 28 would do so with antiangiogenic therapy, meaning that 100 participants need to be treated with antiangiogenic therapy to allow 20 more people (95% CI 13 to 29) to markedly improve their vision after one year. People treated with anti-VEGF on average had 1.6 lines better vision (95% CI 1.4 to 1.8) after one year compared to laser photocoagulation (9 studies, 1292 cases, high quality evidence). To achieve this result, seven to nine injections were delivered in the first year and three or four in the second, in larger studies adopting either as needed regimens with monthly monitoring or fixed regimens.In other analyses antiangiogenic therapy was more effective than sham (3 studies on 497 analysed participants, high quality evidence) and ranibizumab associated with laser was more effective than laser alone (4 studies on 919 participants, high quality evidence).Ocular severe adverse events, such as endophthalmitis, were rare in the included studies. Meta-analyses conducted for all antiangiogenic drugs compared with either sham or photocoagulation did not show a significant difference regarding serious systemic adverse events (15 studies, 441 events in 2985 participants, RR 0.98, 95% CI 0.83 to 1.17), arterial thromboembolic events (14 studies, 129 events in 3034 participants, RR 0.89, 95% CI 0.63 to 1.25) and overall mortality (63 events in 3562 participants, RR 0.88, 95% CI 0.52 to 1.47). We judged the quality of the evidence on adverse effects as moderate due to partial reporting of safety data and the exclusion of participants with previous cardiovascular events in some studies.

AUTHORS' CONCLUSIONS

There is high quality evidence that antiangiogenic drugs provide a benefit compared to current therapeutic options for DMO, that is grid laser photocoagulation, in clinical trial populations at one or two years. Future research should investigate differences between drugs, effectiveness under real-world monitoring and treatment conditions, and safety in high-risk populations, particularly regarding cardiovascular risk.

Efficacy of intravitreal anti-vascular endothelial growth factor or steroid injection in diabetic macular edema according to fluid turbidity in optical coherence tomography

Purpose

To determine if short term effects of intravitreal anti-vascular endothelial growth factor or steroid injection are correlated with fluid turbidity, as detected by spectral domain optical coherence tomography (SD-OCT) in diabetic macular edema (DME) patients.

Methods

A total of 583 medical records were reviewed and 104 cases were enrolled. Sixty eyes received a single intravitreal bevacizumab injection (IVB) on the first attack of DME and 44 eyes received triamcinolone acetonide treatment (IVTA). Intraretinal fluid turbidity in DME patients was estimated with initialintravitreal SD-OCT and analyzed with color histograms from a Photoshop program. Central macular thickness and visual acuity using a logarithm from the minimum angle of resolution chart, were assessed at the initial period and 2 months after injections.

Results

Visual acuity and central macular thickness improved after injections in both groups. In the IVB group, visual acuity and central macular thickness changed less as the intraretinal fluid became more turbid. In the IVTA group, visual acuity underwent less change while central macular thickness had a greater reduction (r = -0.675, p = 0.001) as the intraretinal fluid was more turbid.

Conclusions

IVB and IVTA injections were effective in reducing central macular thickness and improving visual acuity in DME patients. Further, fluid turbidity, which was detected by SD-OCT may be one of the indexes that highlight the influence of the steroid-dependent pathogenetic mechanism.

Cost-effectiveness of treatment of diabetic macular edema

BACKGROUND

Macular edema is the most common cause of vision loss among patients with diabetes.

OBJECTIVE

To determine the cost-effectiveness of different treatments of diabetic macular edema (DME).

DESIGN

Markov model.

DATA SOURCES

Published literature and expert opinion.

TARGET POPULATION

Patients with clinically significant DME.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Laser treatment, intraocular injections of triamcinolone or a vascular endothelial growth factor (VEGF) inhibitor, or a combination of both.

OUTCOME MEASURES

Discounted costs, gains in quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

RESULTS OF BASE-CASE ANALYSIS

All treatments except laser monotherapy substantially reduced costs, and all treatments except triamcinolone monotherapy increased QALYs. Laser treatment plus a VEGF inhibitor achieved the greatest benefit, gaining 0.56 QALYs at a cost of $6975 for an ICER of $12 410 per QALY compared with laser treatment plus triamcinolone. Monotherapy with a VEGF inhibitor achieved similar outcomes to combination therapy with laser treatment plus a VEGF inhibitor. Laser monotherapy and triamcinolone monotherapy were less effective and more costly than combination therapy.

RESULTS OF SENSITIVITY ANALYSIS

VEGF inhibitor monotherapy was sometimes preferred over laser treatment plus a VEGF inhibitor, depending on the reduction in quality of life with loss of visual acuity. When the VEGF inhibitor bevacizumab was as effective as ranibizumab, it was preferable because of its lower cost.

LIMITATION

Long-term outcome data for treated and untreated diseases are limited.

CONCLUSION

The most effective treatment of DME is VEGF inhibitor injections with or without laser treatment. This therapy compares favorably with cost-effective interventions for other conditions.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Visual outcome after intravitreal bevacizumab depends on the optical coherence tomographic patterns of patients with diffuse diabetic macular edema

PURPOSE

The purpose of this study was to evaluate the effectiveness of intravitreal bevacizumab (IVB) on the reduction of diffuse diabetic macular edema in patients with different optical coherence tomography patterns.

DESIGN

Prospective interventional case series.

METHODS

One hundred and forty-three eyes with diffuse diabetic macular edema, without a history of any previous treatment, were classified according to their optical coherence tomography patterns: sponge-like diffuse retinal thickening (SDRT) (n = 50), cystoid macular edema (CME) (n = 38), serous retinal detachment (SRD) (n = 25), and the combination of all patterns (FULL: n = 30). All the participants received a single dose (1.25 mg in 0.05 mL) of IVB. The foveal thickness obtained with optical coherence tomography images and logarithm of the minimum angle of resolution visual acuity were assessed before receiving IVB and subsequently every 2 weeks for 12 weeks.

RESULTS

After IVB, the foveal thickness in all the groups was reduced but the reduction ratio in the SDRT (29.6 ± 15.6%) and CME (27.1 ± 20.5%) groups was significantly greater than in the SRD group (16.4 ± 17.7%) (P < 0.001). Similarly, improvement of visual acuity in the SDRT (-0.21 ± 0.16) and CME (-0.17 ± 0.24) groups was significantly greater than in the SRD (-0.12 ± 0.15) and FULL (-0.11 ± 0.13) (P = 0.047) groups. Interestingly, the efficacy of IVB for regression of diffuse diabetic macular edema was dependent on the duration of diabetes in the SDRT and CME groups but not in the SRD or FULL groups.

CONCLUSION

The effectiveness of IVB on diffuse diabetic macular edema was dependent on the optical coherence tomography pattern (SDRT ≥ CME >> SRD), indicating that vascular endothelial growth factor plays a critical role in the pathogenesis of SDRT and CME, and was greater in patients having diabetes for a shorter duration of time.

Structural and functional measures of efficacy in response to bevacizumab monotherapy in diabetic macular oedema: exploratory analyses of the BOLT study (report 4)

Background

To describe structural and functional changes associated with diabetic macular oedema (DMO) treated with intravitreal bevacizumab over 24 months.

Methods

A post-hoc analysis of the data of 34 patients that completed 24 months follow-up in the intravitreal bevacizumab arm of a prospective, randomized controlled trial (BOLT study) was performed. The outcome measures previously used in clinical trials of intravitreal ranibizumab in DMO were employed to describe the visual acuity and macular thickness changes at 12 and 24 months.

Results

The standard outcomes of mean change in best corrected visual acuity (BCVA) and central macular thickness (CMT) in participants treated with bevacizumab were comparable to those reported in association with ranibizumab. However, exploratory analyses showed that thick maculae at baseline defined as CMT of ≥400 µm, remained significantly thicker than those <400 µm with intensive bevacizumab therapy, despite a comparable gain in visual acuity at both 12 and 24 months. The proportion of subjects that attained a dry macula doubled in both CMT groups between the 12 and 24-month time-points.

Conclusions

These findings provide valuable information both for clinical practice and trials. Further studies are required to investigate the impact of intravitreal bevacizumab on retinal thickness profiles in DMO.

Intravitreal triamcinolone versus intravitreal bevacizumab for diabetic macular edema: a meta-analysis

AIM

To compare the efficacy of the sole intravitreal triamcinolone (IVT) versus intravitreal bevacizumab (IVB) alone or IVB combined with IVT in the treatment of diabetic macular edema (DME).

METHODS

Pertinent publications were identified through systematic searches of database and manually searching. Methodological quality of the literatures was valuated according to the Jadad Score. RevMan 5.1.0 was used to do the meta-analysis. Heterogeneity was determined and sensitivity was conducted.

RESULTS

Six studies were ultimately included in the meta-analysis. The results of our analysis showed IVT had a statistically significant improvement in vision over the IVB at 1 month and 3 months (P<0.01). However, the reduction was not significant regarding central macular thickness (CMT) during the earlier (1 month and 3 months) follow-up period (P=0.12, P=0.41, respectively). At later visit (6 months), IVT had a significant decrease in CMT when compared to IVB (P<0.01) while no significant improvement in visual acuity (VA) was observed (P=0.14). The incidence of intraocular hypertension was 13/102 in IVT group during follow-up period while 0/103 in IVB group. The difference was significant (P<0.01). With regards to IVT versus IVB combined with IVT, there were no significant differences in CMT at 1 month (P=0.86) and 3 months (P=0.06). The incidence of intraocular hypertension was 6/67 in IVT group during follow-up period while 4/66 in IVB+IVT group. But the difference was not significant (P=0.53).

CONCLUSION

Current evidence shows IVT is superior in improving VA at earlier follow-up (1 month and 3 months) and in reducing CMT at later follow-up (6 months) for DME. At other time, it is in favor of IVT treatment but there are no statistically significances. However, IVT has the side-effect of ocular hypertension. There is no adequate evidence of the benefit adding IVB to IVT in contrast to IVT alone.

Evolving strategies in the management of diabetic macular edema: clinical trials and current management

Diabetic macular edema (DME) is the leading cause of vision loss in the working-age population in developed countries. Management has traditionally consisted of focal/grid macular laser, according to the guidelines established by the Early Treatment of Diabetic Retinopathy Study. More recent prospective clinical trials examining the effect of intravitreal ranibizumab in the treatment of DME--most notably, READ-2, RESOLVE, RESTORE, RISE/RIDE, and DRCR.net protocol I--have demonstrated improved visual outcomes with pharmacologic targeting of vascular endothelial growth factor. Similar treatment benefits have also been noted in clinical trials evaluating intravitreal bevacizumab and aflibercept (Bolt and da Vinci, respectively). Intravitreal steroids, particularly in refractory cases, continue to have a limited role in the management of DME. In patients with symptomatic visual loss, the treatment paradigm for DME has shifted toward intravitreal pharmacotherapeutics, principally anti-vascular endothelial growth factor therapy, and this review examines the clinical trials leading to this change.

Antiangiogenic therapy with anti-vascular endothelial growth factor modalities for diabetic macular oedema

BACKGROUND

Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy. Although grid or focal laser photocoagulation has been shown to reduce the risk of visual loss in DMO or clinically significant macular oedema (CSMO), vision is rarely improved. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) modalities has recently been proposed for improving vision in people with DMO.

OBJECTIVES

To assess the effectiveness, safety and cost-effectiveness of anti-VEGF therapy for preserving or improving vision in people with DMO.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 6), MEDLINE (January 1946 to June 2012), EMBASE (January 1980 to June 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing any antiangiogenic drugs with an anti-VEGF mechanism of action versus another treatment, sham treatment, or no treatment in patients with DMO. We also included economic evaluations to assess cost-effectiveness.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data. The risk ratio (RR) of visual loss and visual gain of three or more lines was estimated at least six months after treatment. Each economic analysis was described narratively using a structured format.

MAIN RESULTS

Eleven studies provided data on three comparisons of interest in this review. We based our conclusions on the RR of gain or loss of three or more lines of vision at about one year, which was more consistently reported as follow-up.Compared with sham treatment, there was evidence of moderate quality in three studies (497 participants, follow-up 8 to 12 months) that antiangiogenic therapy (pegaptanib: two studies, 246 participants; ranibizumab: one study, 151 participants) doubled and, respectively, halved, the chance of gaining or losing three or more lines of vision (RR: 2.19, 95% confidence interval (CI) 1.36 to 3.53; RR: 0.28, 95% CI: 0.13 to 0.59). In meta-analyses, the benefit was larger for ranibizumab compared to pegaptanib, but no significant subgroup difference could be demonstrated regarding our primary outcome.Compared with grid laser photocoagulation, there was evidence of moderate quality that antiangiogenic therapy (bevacizumab: two studies, 167 participants; ranibizumab: two studies, 300 participants; aflibercept: one study, 221 participants, 89 used for data extraction) more than doubled and, respectively, reduced by at least two thirds, the chance of gaining or losing three or more lines of vision (RR: 3.20, 95% CI 2.07 to 4.95 and RR: 0.13, 95% CI: 0.05 to 0.34, respectively). In meta-analyses, no significant subgroup difference could be demonstrated between bevacizumab, ranibizumab and aflibercept regarding our primary outcome, but, again, there was little power to detect a difference.Compared with grid laser photocoagulation alone, there was high quality evidence that ranibizumab plus photocoagulation (three studies, 783 participants) doubled and, respectively, at least halved, the chance of gaining or losing three or more lines of vision (RR: 2.11, 95% CI 1.67 to 2.67; RR: 0.29, 95% CI: 0.15 to 0.55).Systemic and ocular adverse events were rare in the included studies. Meta-analyses conducted for all antiangiogenic drugs compared with either sham or photocoagulation (nine studies, 104 events in 2159 participants) did not show a significant difference regarding arterial thromboembolic events (RR: 0.85 (0.56 to 1.28). Similarly, no difference was suggested regarding overall mortality (53 events, RR: 0.95 (0.52 to 1.74), but clinically significant differences could not be ruled out.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that antiangiogenic drugs provide a definite, but small, benefit compared to current therapeutic options for DMO, i.e. grid laser photocoagulation, or no treatment when laser is not an option. The quality and quantity of the evidence was larger for ranibizumab, but there was little power to investigate drug differences. Most data were obtained at one year, and a long-term confirmation is needed, since DMO is a chronic condition. Safety of both drug and the intravitreal injection procedure were good in the trials, but further long-term data are needed to exclude small, but clinically important differences regarding systemic adverse events.

The use of comparative effectiveness research to inform policy decisions on the inclusion of bevacizumab for the treatment of macular diseases in Thailand's pharmaceutical benefit package

There is increasing impetus to use pharmaceutical interventions, ie, ranibizumab or bevacizumab, for the treatment of particular macular diseases. This paper describes the evidence and decision-making of the National List of Essential Medicines Committee that recently announced the inclusion of bevacizumab for the treatment of macular diseases in its pharmaceutical benefit package. The findings of a systematic review and meta-analysis in this paper indicate that the intravitreal administration of bevacizumab is superior to nonpharmaceutical treatments for age-related macular degeneration (AMD) and diabetic macular edema (DME), but inconclusive for retinal vein occlusion, given the limited evidence. The study also failed to distinguish among the differences in terms of visual acuity improvement, reduction of central macular thickness, and response to treatment between AMD and DME patients treated with bevacizumab and those treated with ranibizumab. Although bevacizumab was not licensed for AMD and DME, the committee decided to include bevacizumab in the National List of Essential Medicines. It is expected that many patients who are in need of treatment but who are unable to afford the expensive alternative drug, ranibizumab, will be able to receive this effective treatment instead and be prevented from suffering irreversible loss of vision. At the same time, this policy will help generate evidence about the real-life effectiveness and safety profiles of the drug for future policy development in Thailand and other settings.

Evidence for anti-VEGF treatment of diabetic macular edema

Diabetic macular edema (DME) is the most important cause of vision loss in patients with diabetes mellitus. Diabetic retinopathy has a remarkable impact on public health and on the quality of life of diabetic patients and thus requires special consideration. The first line of treatment remains the management of systemic risk factors but is often insufficient in controlling DME and currently, laser retinal photocoagulation is considered the standard of care. However, laser treatment reduces the risk of moderate visual loss by approximately 50% without guaranteeing remarkable effects on visual improvement. For these reasons, new strategies in the treatment of DME have been studied, in particular the use of anti-vascular endothelial growth factor (anti-VEGF) drugs. VEGF is a pluripotent growth factor that acts as a vasopermeability factor and an endothelial cell mitogen. For this reason, it represents an interesting candidate as a therapeutic target for the treatment of DME. The aim of this article is to review the evidence behind the use of anti-VEGF drugs in the treatment of DME.

The relative clinical effectiveness of ranibizumab and bevacizumab in diabetic macular oedema: an indirect comparison in a systematic review

OBJECTIVE

To indirectly compare the effectiveness of ranibizumab and bevacizumab in the treatment of diabetic macular oedema.

DESIGN

Systematic review and indirect comparison.

DATA SOURCES

Medline (1996-September 2011), Embase (1996-September 2011), and the Cochrane Central Register of Controlled Trials (Issue 4, 2011).

SELECTION CRITERIA FOR STUDIES

Randomised trials evaluating ranibizumab or bevacizumab in diabetic macular oedema with a common comparator and sufficient methodological similarity to be included within an indirect comparison were eligible for inclusion.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of patients with an improvement in best corrected visual acuity of more than two lines on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Secondary outcomes included mean changes in best corrected visual acuity and in central macular thickness, and adverse events. Best corrected visual acuity was converted to logMAR units, a linear scale of visual acuity with positive values representing increasing visual loss. Indirect comparisons were done using Bayesian methods to estimate relative treatment effects of bevacizumab and ranibizumab.

RESULTS

Five randomised controlled trials with follow-up of 6-12 months and a common comparator (multiple laser treatment) were sufficiently similar to be included in the indirect comparison. Generally studies were small, resulting in wide credible intervals. The proportions of patients with an improvement in best corrected visual acuity of >2 lines were 21/77 participants (27%) for bevacizumab and 60/152 participants (39%) for ranibizumab (odds ratio 0.95 (95% credible interval 0.23 to 4.32)). The wide credible intervals cannot exclude a greater improvement, or worse outcome, for either drug. The mean change in best corrected visual acuity non-significantly favoured bevacizumab (treatment effect -0.08 logMAR units (-0.19 to 0.04)). The difference in mean change in central macular thickness was not statistically significant between ranibizumab and bevacizumab (treatment effect -6.9 μm (-88.5 to 65.4)).

CONCLUSIONS

Results suggest no difference in effectiveness between bevacizumab and ranibizumab, but the wide credible intervals cannot exclude the possibility that either drug might be superior. Sufficiently powered, direct head to head trials are needed.

Correlation of macular thickness and posterior hyaloid change following bevacizumab and triamcinolone in diffuse diabetic macular edema in middle-aged patients

To compare changes in posterior vitreous detachment (PVD) following intravitreal injection of bevacizumab and triamcinolone in diffuse diabetic macular edema in middle-aged type 2 diabetes patients and to correlate this change with change in central macular thickness (CMT).

DESIGN

cross sectional study. Fifteen consecutive patients treated by intravitreal bevacizumab (group A) and ten patients treated by intravitreal triamcinolone (group B). Institutional study carried out by retrospective analysis of patient registers including serial optical coherence tomography (OCT) images at baseline, and after 1 and 4 months. A central macular thickness (CMT) and vitreomacular relationship was noted on OCT. PVD was graded on a linear scale (0-4). Change in grade of PVD was correlated with change in CMT at each follow-up. At month 4, the decrease in mean CMT from baseline was 51.2 μ (P = 0.000) and 45 μ (P = 0.022) in group A and group B, respectively, with no significant difference between the two groups (P = 0.874). A change in grades of PVD from baseline to month 4 was significant in both group A (P = 0.001) and group B (P = 0.004) with no significant difference between the two groups (P = 0.906). A significant correlation between change in PVD and reduction of CMT was observed in group A (P = 0.011) but not in group B (P = 0.315). Both bevacizumab and triamcinolone caused a significant reduction in macular thickness and a significant change in grade of PVD. Change in PVD played an influential role in the reduction of macular thickness following bevacizumab.

Comparison of grid laser, intravitreal triamcinolone, and intravitreal bevacizumab in the treatment of diffuse diabetic macular edema

PURPOSE

To compare the effects of grid laser (GL), intravitreal bevacizumab (IVB), and intravitreal triamcinolone acetonide (IVTA) in diffuse diabetic macular edema (DDME).

PROCEDURES

One hundred and twenty-six patients (126 eyes) treated with GL (modified grid), IVTA (4 mg), and IVB (1.25 mg) injections, matched for best corrected visual acuity (BCVA) and OCT-based central macular thickness at presentation, were enrolled. Primary outcome measure was change in best corrected logMAR visual acuity at 1-year follow-up.

RESULTS

Rates of visual stabilization (within ±0.2 logMAR of baseline BCVA) (71.4, 83.3, 78.6%, respectively) were not different between the groups (p = 0.41) at 12-month follow-up. Higher rates of anatomical and functional success, however, were evident in IVB and IVTA groups within 6 months of treatment (p < 0.05 for both). No severe adverse effects except higher intraocular pressure (10 mm Hg from baseline) in one third (14 eyes) of the IVTA cases, who required trabeculectomy in 2 (4.8%) eyes, were observed.

CONCLUSIONS

Intraocular injections may give favorable results within the first 6 months, and after 6 months, GL results seem to be more favorable in the treatment of treatment-naïve, acute, nonischemic, and center-involving DDME.

Review of therapeutic advances in diabetic retinopathy

Diabetic retinopathy is a common microvascular complication of prolonged diabetes. It is one of the leading causes of vision loss in working age adults and a significant source of morbidity. To reduce the incidence and severity of diabetic retinopathy, it is important to identify patients at risk and promptly implement intensive glycemic and hypertensive control. To date, there are many interventions that can limit moderate and severe vision loss in people with diabetes, including laser photocoagulation, vitrectomy surgery, and intravitreal pharmacological injections. This review aims to define the different stages of diabetic retinopathy and the important therapeutic advances developed to address the major causes of vision loss in each stage.