Efficacy of anti-VEGF and laser photocoagulation in the treatment of visual impairment due to diabetic macular edema: a systematic review and network meta-analysis

How early can we detect diabetic retinopathy? A narrative review of imaging tools for structural assessment of the retina

Despite current screening models, enhanced imaging modalities, and treatment regimens, diabetic retinopathy (DR) remains one of the leading causes of vision loss in working age adults. DR can result in irreversible structural and functional retinal damage, leading to visual impairment and reduced quality of life. Given potentially irreversible photoreceptor damage, diagnosis and treatment at the earliest stages will provide the best opportunity to avoid visual disturbances or retinopathy progression. We will review herein the current structural imaging methods used for DR assessment and their capability of detecting DR in the first stages of disease. Imaging tools, such as fundus photography, optical coherence tomography, fundus fluorescein angiography, optical coherence tomography angiography and adaptive optics-assisted imaging will be reviewed. Finally, we describe the future of DR screening programmes and the introduction of artificial intelligence as an innovative approach to detecting subtle changes in the diabetic retina. CLINICAL TRIAL REGISTRATION NUMBER: N/A.

Differential artery-vein analysis in OCTA for predicting the anti-VEGF treatment outcome of diabetic macular edema

This study evaluates the role of differential artery-vein (AV) analysis in optical coherence tomography angiography (OCTA) for treatment outcome prediction of diabetic macular edema (DME). Deep learning AV segmentation in OCTA enabled the robust extraction of quantitative AV features, including perfusion intensity density (PID), blood vessel density (BVD), vessel skeleton density (VSD), vessel area flux (VAF), blood vessel caliber (BVC), blood vessel tortuosity (BVT), and vessel perimeter index (VPI). Support vector machine (SVM) classifiers were employed to predict changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT). Comparative analysis revealed that differential AV analysis significantly enhanced prediction performance, with BCVA accuracy improved from 70.45% to 86.36% and CRT accuracy enhanced from 68.18% to 79.55% compared to traditional OCTA analysis. These findings underscore the potential of AV analysis as a transformative tool for advancing personalized therapeutic strategies and improving clinical decision-making in managing DME.

Müller cells and retinal angiogenesis: critical regulators in health and disease

Müller cells are the most abundant glial cells in the mammalian retina. Their morphology and metabolism enable them to be in close contact and interact biochemically and physically with almost all retinal cell types, including neurons, pericytes, endothelial cells, and other glial cells, influencing their physiology by releasing bioactive molecules. Studies indicate that Müller glial cells are the primary source of angiogenic growth factor secretion in the neuroretina. Because of this, over the past decade, it has been postulated that Müller glial cells play a significant role in maintaining retinal vascular homeostasis, with potential implications in vasoproliferative retinopathies. This review aims to summarize the current understanding of the mechanisms by which Müller glial cells influence retinal angiogenesis in health and disease, with a particular emphasis on three of the retinopathies with the most significant impact on visual health worldwide: diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration.

Anti-VEGF therapy for the long-term management of diabetic macular edema: a treat-to-target strategy based on macular morphology

In an aging population, the prevalence and burden of diabetes mellitus, diabetic retinopathy, and vision-threatening diabetic macular edema (DME) are only expected to rise around the world. Similarly to other complications of diabetes mellitus, DME requires long-term management. This article aims to review the current challenges associated with the long-term management of DME, opportunities to improve outcomes for patients, and to develop a treat-to-target strategy based on macular morphology. At present, intravitreal anti-vascular endothelial growth factor (VEGF) therapy is the standard of care for the management of DME; however, best-achievable vision outcomes with treatment are reliant on frequent injections and close monitoring, which are difficult to maintain in current clinical practice because of the burden this imposes on patients. Achieving and maintaining good vision with treatment are the most important factors for patients with DME. Landmark trials have shown that vision gains with anti-VEGF therapy are typically accompanied by anatomical improvements (e.g., reductions in retinal thickness); therefore, multimodal imaging measures of macular morphology are often used in patients with DME to guide real-world treatment decisions. We would like to propose a hypothetical treat-to-target algorithm to guide physicians on treatment strategies for the long-term management of DME. Alternative measures of retinal fluid (e.g., persistence, stability, location) may be stronger predictors of visual acuity in DME, although further research is required to confirm whether alternate quantifiable biomarkers such as subretinal fluid and intraretinal fluid volumes can be used as a biomarker of clinical improvement. Identifying novel biomarkers and treatments that target neuroinflammation and neurodegeneration, improving patient-physician communication around treatment adherence, and using treat-to-target measures may help to ensure that the long-term benefits of treatment are realized.

Aflibercept versus ranibizumab for diabetic macular edema: A meta-analysis

OBJECTIVE

The purpose of this study was to compare the efficacy and safety of aflibercept (AFL) versus ranibizumab (RAN) for the treatment of diabetic macular edema (DME).

METHODS

The PubMed, Embase, Cochrane Library, and CNKI databases were searched up to September 2022 to identify prospective randomized controlled trials (RCTs) comparing AFL with RAN for the treatment of DME. Review Manager 5.3 software was used for data analysis. We used the GRADE system to evaluate the quality of the evidence for each outcome.

RESULTS

A total of 8 RCTs involving 1067 eyes (939 patients) were included; there were 526 eyes in the AFL group and 541 eyes in the RAN group. Meta-analysis revealed that there was no significant difference between RAN and AFL in the best-corrected visual acuity (BCVA) of DME patients at 6 months (WMD: -0.05, 95% CI  =  -0.12 to 0.01, moderate quality) and 12 months after injection (WMD: -0.02, 95% CI  =  -0.07 to 0.03, moderate quality). Additionally, there was no significant difference between RAN and AFL in the reduction of central macular thickness (CMT) at 6 months (WMD: -0.36, 95% CI  =  -24.99 to 24.26, very low quality) and 12 months after injection (WMD: -6.36, 95% CI  =  -16.30 to 3.59, low quality). Meta-analysis showed that the number of intravitreal injections (IVIs) for AFL was significantly lower than that for RAN (WMD: -0.47, 95% CI  =  -0.88 to -0.05, very low quality). There were fewer adverse reactions to AFL than to RAN, but the difference was not significant.

CONCLUSION

This study found that there was no difference in BCVA, CMT or adverse reactions between AFL and RAN at 6 and 12 months of follow-up, but AFL needed fewer IVIs than RAN.

Cost-Effectiveness of Faricimab in the Treatment of Diabetic Macular Oedema (DMO): A UK Analysis

AIM

The aim of this work was to evaluate the cost-effectiveness of faricimab against relevant therapeutic alternatives used in clinical practice for the treatment of diabetic macular oedema (DMO) in the UK.

METHODS

A state-transition (Markov) model, with health states based on visual acuity scores and treatment pathways, was developed to conduct cost-utility analysis of faricimab treat and extend (T&E) regimen versus ranibizumab pro re nata (PRN) and aflibercept PRN over a time horizon of 25 years. Comparison against bevacizumab PRN was considered in scenario analysis. Effectiveness data for faricimab was sourced from the pivotal YOSEMITE and RHINE double-blind randomised controlled trials, and from a network meta-analysis for comparators. Costs and (dis)utilities were taken from nationally published sources or literature. The base case included indirect costs (productivity gains, informal care) given the wider impacts of DMO on society. Sensitivity analyses were conducted.

RESULTS

In the base case, faricimab T&E dominated ranibizumab PRN and aflibercept PRN, being more effective and resulting in cost savings (between 0.16 and 0.36 mean QALYs gained, and £5483-9655 mean cost savings). In scenario analysis, faricimab was more effective but costlier compared with bevacizumab, with an incremental cost-effectiveness ratio (ICER) of £8898 per QALY gained. Considering only healthcare payer costs, the ICER of faricimab compared with ranibizumab PRN was £7991 per QALY gained and faricimab dominated aflibercept PRN.

CONCLUSIONS

Faricimab T&E has the potential to reduce the burden of vision loss on society, giving people living with DMO greater independence and contributing to increased healthcare system capacity. At a threshold of £20,000, faricimab T&E is cost-effective compared with relevant comparators, and potentially cost saving.

Cardiovascular Outcomes with Intravitreal Anti-Vascular Endothelial Growth Factor Therapy in Patients with Diabetes: A Real-World Data Analysis

BACKGROUND

Anti-vascular endothelial growth factor (anti-VEGF) therapy is commonly used intravitreally for diabetic proliferative retinopathy, but when used systemically for treating cancers, an excess of cardiovascular disease (CVD) events has been noted. The latter is of concern for people with diabetes, who are at higher risk of CVD. This study aims to explore the relationship between incident CVD and intravitreal anti-VEGF therapy in patients with diabetes, compared to other therapies, using a large real-world global federated dataset.

METHODS

Data were analysed using TriNetX, a global electronic medical real-world ecosystem. The study included adults with diabetes and excluded those with a history of CVD prior to the time window of data extraction. Patients were categorised into two cohorts: anti-VEGF therapy or control cohort (laser or steroid therapies). The cohorts were 1:1 propensity score-matched for age, sex, ethnicity, body mass index, systolic blood pressure, HbA1c, and cardiovascular medications. Outcomes analysed at 1, 6 and 12 months were: (1) mortality; (2) acute myocardial infarction (MI); (3) cerebral infarction; and (4) heart failure. Relative risk analyses were performed using the built-in R statistical computing platform on TriNetX.

RESULTS

In patients with diabetes (n = 2205; mean age 58.8 ± 15.8, Std diff 0.05; 56% male), anti-VEGF therapy was associated with a numerical but non-statistically significant increased CVD risk over 1, 6, and 12 months: Mortality over 1 month (RR 1; 95% CI 0.42, 2.40), 6 months (RR 1.46; 95% CI 0.72, 2.95) and 12 months (RR 1.41; 95% CI 0.88, 2.27). There was no excess of acute MI over 1 (RR n/a: not applicable; 0/0: 0 events in the anti-VEGF group/0 events in the control group), 6 and 12 months (RR n/a; 0/10 events); cerebral infarction over 1, 6 months (RR n/a; 0/0 events), and 12 months (RR n/a; 0/10); and heart failure over 1 month (RR n/a; 0/0 events), 6 months (RR 1; 95% CI 0.42, 2.40) and 12 months (RR 1; 95% CI 0.42, 2.34).

CONCLUSIONS

There was no statistically significant risk of cardiovascular-related events in the short or medium term in patients with diabetes who received intravitreal anti-VEGF therapy, despite a small increase in the number of CVD events. Our study supports the real-world safety of intravitreal anti-VEGF therapy in patients with diabetes free of baseline CVD.

Comparative Efficacy, Durability and Safety of Faricimab in the Treatment of Diabetic Macular Edema: A Systematic Literature Review and Network Meta-Analysis

INTRODUCTION

A systematic literature review (SLR) and network meta-analysis (NMA) were conducted to evaluate the comparative efficacy, durability and safety of faricimab, used in a Treat & Extend (T&E) regime with intervals up to every 16 weeks (Q16W), relative to other therapies currently in use for treatment of diabetic macular oedema (DME). Of particular interest were anti-vascular endothelial growth factor (VEGF) therapies applied in flexible dosing regimens such as Pro re nata (PRN) and T&E, which are the mainstay in clinical practice.

METHODS

An SLR identifying randomised controlled trials (RCTs) published before August 2021 was conducted, followed by a Bayesian NMA comparing faricimab T&E treatment to aflibercept, ranibizumab, bevacizumab, dexamethasone and laser therapy. Outcomes included in the analysis were change in best-corrected visual acuity (BCVA), change in central subfield thickness (CST), injection frequency, ocular adverse events (AE) and all-cause discontinuation, all of which were evaluated at 12 months. Subgroup analyses including patients' naïve to anti-VEGF were conducted where feasible.

RESULTS

Twenty-six studies identified in the SLR were included in the NMA. Most importantly for decision making in clinical practise, faricimab T&E was associated with a statistically greater (95% credible intervals exclude zero) and clinically meaningful decrease in retinal thickness compared to all other flexible dosing regimens (greater retinal drying by 55-125 microns). Anatomical outcomes determine treatment efficacy and retreatment of patients. The NMA also showed a statistically greater increase in mean change in BCVA for faricimab T&E vs. flexible regimens using ranibizumab and bevacizumab (increase of 4.4-4.8 letters) as well as a numerical improvement vs. aflibercept PRN (two letters, 95% credible intervals including zero). Accordingly, the injection frequency was numerically lower versus other treatments using flexible dosing regimens (decrease by 0.92-1.43 injections). The analyses also indicated that the safety profile of faricimab T&E was comparable to those of ranibizumab and aflibercept, which have well-established safety profiles, with similar results for the number of all-cause discontinuations.

CONCLUSION

Faricimab provides a new treatment option in DME with dual-pathway inhibition of VEGF and angiopoeitin-2 (Ang-2). To the authors' knowledge, this is the first indirect comparison of faricimab T&E in DME. The analyses indicate that faricimab T&E is associated with superior retinal drying along with numerically fewer injections compared to all other treatments given in flexible dosing regimens. It also showed superior visual acuity outcomes compared to ranibizumab and bevacizumab.

From randomised controlled trials to real-world data: Clinical evidence to guide management of diabetic macular oedema

Randomised clinical trials (RCTs) are generally considered the gold-standard for providing scientific evidence for treatments' effectiveness and safety but their findings may not always be generalisable to the broader population treated in routine clinical practice. RCTs include highly selected patient populations that fit specific inclusion and exclusion criteria. Although they may have a lower level of certainty than RCTs on the evidence hierarchy, real-world data (RWD), such as observational studies, registries and databases, provide real-world evidence (RWE) that can complement RCTs. For example, RWE may help satisfy requirements for a new indication of an already approved drug and help us better understand long-term treatment effectiveness, safety and patterns of use in clinical practice. Many countries have set up registries, observational studies and databases containing information on patients with retinal diseases, such as diabetic macular oedema (DMO). These DMO RWD have produced significant clinical evidence in the past decade that has changed the management of DMO. RWD and medico-administrative databases are a useful resource to identify low frequency safety signals. They often have long-term follow-up with a large number of patients and minimal exclusion criteria. We will discuss improvements in healthcare information exchange technologies, such as blockchain technology and FHIR (Fast Healthcare Interoperability Resources), which will connect and extend databases already available. These registries can be linked with existing or emerging retinal imaging modalities using artificial intelligence to aid diagnosis, treatment decisions and provide prognostic information. The results of RCTs and RWE are combined to provide evidence-based guidelines.

Diversity when interpreting evidence in network meta-analyses (NMAs) on similar topics: an example case of NMAs on diabetic macular oedema

BACKGROUND

Different network meta-analyses (NMAs) on the same topic result in differences in findings. In this review, we investigated NMAs comparing aflibercept with ranibizumab for diabetic macular oedema (DME) in the hope of illuminating why the differences in findings occurred.

METHODS

Studies were searched for in English and Chinese electronic databases (PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang, VIP; see detailed search strategy in the main body). Two independent reviewers systematically screened to identify target NMAs that included a comparison of aflibercept and ranibizumab in patients with DME. The key outcome of interest in this review is the change in best-corrected visual acuity (BCVA), including various ways of reporting (such as the proportion of participants who gain ≥ 10 ETDRS letters at 12 months; average change in BCVA at 12 months).

RESULTS

For the binary outcome of BCVA, different NMAs all agreed that there is no clear difference between the two treatments, while continuous outcomes all favour aflibercept over ranibizumab. We discussed four points of particular concern that are illustrated by five similar NMAs, including network differences, PICO (participants, interventions, comparators, outcomes) differences, different data from the same measures of effect, and differences in what is truly significant.

CONCLUSIONS

A closer inspection of each of these trials shows how the methods, including the searches and analyses, all differ, but the findings, although presented differently and sometimes interpreted differently, were similar.

Research progress on the mechanism of ferroptosis and its role in diabetic retinopathy

Ferroptosis is iron-dependent regulatory cell death (RCD). Morphologically, ferroptosis is manifested as mitochondrial atrophy and increased mitochondrial membrane density. Biochemically, ferroptosis is characterized by the depletion of glutathione (GSH), the inactivation of glutathione peroxidase 4 (GPX4), and an increase in lipid peroxides (LPO)and divalent iron ions. Ferroptosis is associated with various diseases, but the relationship with diabetic retinopathy(DR) is less studied. DR is one of the complications of diabetes mellitus and has a severe impact on visual function. The pathology of DR is complex, and the current treatment is unsatisfactory. Therefore, exploring pathogenesis is helpful for the clinical treatment of DR. This paper reviews the pathological mechanism of ferroptosis and DR in recent years and the involvement of ferroptosis in the pathology of DR. In addition, we propose problems that need to be addressed in this research field. It is expected to provide new ideas for treating DR by analyzing the role of ferroptosis in DR.

Laser Treatment Modalities for Diabetic Retinopathy

Diabetes is a chronic progressive metabolic disorder that is caused by the body's inability to regulate blood glucose levels. If uncontrolled, it can lead to various complications. Among its various complications, long-term diabetes leads to diabetic retinopathy (DR). It is a disease involving blood vessels and the destruction of retinal nerves. It is usually classified into two types: proliferative diabetic retinopathy (PDR) and nonproliferative diabetic retinopathy (NPDR). It progresses and causes loss of vision. The leading cause of loss of vision is diabetic macular edema (DME). The argon laser is used as a modality in the management of PDR. There are various types of laser photocoagulation, such as peripheral retinal laser photocoagulation, focal macular laser photocoagulation, and grid photocoagulation. DR results in various adverse consequences such as vitreous hemorrhage, fibrosis, traction, detachment of the retina, and glaucoma. To assess DR, a detailed fundus examination with a slit lamp biomicroscope needs to be done. Seven-standard field stereoscopic-color fundus photography needs to be done for documentation and follow-up. Patients with diabetes mellitus (DM) type 1 have a greater risk of suffering from DR. Another major complication of the condition is DME, which is characterized by an increase in the permeability of vessels and the thickening of the central part of the retina along with the accumulation of hard exudates on the macula. This article discusses various laser therapy modalities for the treatment of DR, their types, mechanisms, and aims. Clinical features of DR include abnormal dilatation of capillaries, and outpouchings in the form of microaneurysm from the capillary wall are one of the earliest and most dangerous changes; later, non-perfusion of the retina occurs, which is associated with cotton wool spots and blot hemorrhages. In patients suffering from PDR and maculopathy, peripheral retinal laser photocoagulation is used as a mode of intervention.

Prediction of the Short-Term Therapeutic Effect of Anti-VEGF Therapy for Diabetic Macular Edema Using a Generative Adversarial Network with OCT Images

Purpose: To generate and evaluate individualized post-therapeutic optical coherence tomography (OCT) images that could predict the short-term response of anti-vascular endothelial growth factor (VEGF) therapy for diabetic macular edema (DME) based on pre-therapeutic images using generative adversarial network (GAN). Methods: Real-world imaging data were collected at the Department of Ophthalmology, Qilu Hospital. A total of 561 pairs of pre-therapeutic and post-therapeutic OCT images of patients with DME were retrospectively included in the training set, 71 pre-therapeutic OCT images were included in the validation set, and their corresponding post-therapeutic OCT images were used to evaluate the synthetic images. A pix2pixHD method was adopted to predict post-therapeutic OCT images in DME patients that received anti-VEGF therapy. The quality and similarity of synthetic OCT images were evaluated independently by a screening experiment and an evaluation experiment. Results: The post-therapeutic OCT images generated by the GAN model based on big data were comparable to the actual images, and the response of edema resorption was also close to the ground truth. Most synthetic images (65/71) were difficult to differentiate from the actual OCT images by retinal specialists. The mean absolute error (MAE) of the central macular thickness (CMT) between the synthetic OCT images and the actual images was 24.51 ± 18.56 μm. Conclusions: The application of GAN can objectively demonstrate the individual short-term response of anti-VEGF therapy one month in advance based on OCT images with high accuracy, which could potentially help to improve treatment compliance of DME patients, identify patients who are not responding well to treatment and optimize the treatment program.

Prediction of Visual Acuity after anti-VEGF Therapy in Diabetic Macular Edema by Machine Learning

PURPOSE

To predict visual acuity (VA) 1 month after anti-vascular endothelial growth factor (VEGF) therapy in patients with diabetic macular edema (DME) by using machine learning.

METHODS

This retrospective study included 281 eyes with DME receiving intravitreal anti-VEGF treatment from January 1, 2019, to April 1, 2021. Eighteen features from electronic medical records and measurements data from OCT images were extracted. The data obtained from January 1, 2019, to November 1, 2020, were used as the training set; the data obtained from November 1, 2020, to April 1, 2021, were used as the validation set. Six different machine learning algorithms were used to predict VA in patients after anti-VEGF therapy. After the initial detailed investigation, we designed an optimization model for convenient application. The VA predicted by machine learning was compared with the ground truth.

RESULTS

The ensemble algorithm (linear regression + random forest regressor) performed best in VA and VA variance predictions. In the validation set, the mean absolute errors (MAEs) of VA predictions were 0.137-0.153 logMAR (within 7-8 letters), and the mean square errors (MSEs) were 0.033-0.045 logMAR (within 2-3 letters) for the 1-month VA predictions, respectively. For the prediction of VA variance at 1 month, the MAEs were 0.164-0.169 logMAR (within 9 letters), and the MSEs were 0.056-0.059 logMAR (within 3 letters), respectively.

CONCLUSIONS

Our machine learning models could accurately predict VA and VA variance in DME patients receiving anti-VEGF therapy 1 month after, which would be much valuable to guide precise individualized interventions and manage expectations in clinical practice.

Efficacy and safety of aflibercept therapy for diabetic macular edema: A systematic review and meta-analysis

Purpose:

To assess the real-world efficacy and safety of aflibercept for the treatment of diabetic macular edema (DME).

Methods:

A systematic search was conducted across multiple databases. Articles were included if participants had DME and received aflibercept treatment for a minimum of 52 ± 4 weeks. Primary outcomes included changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT). A risk of bias assessment of studies was completed, pooled estimates were obtained, and a meta-regression was performed. Information on adverse events was collected.

Results:

The search yielded 2112 articles, of which 30 were included. Aflibercept was more effective than laser photocoagulation functionally (12-month BCVA-weighted mean difference [WMD] = 10.77 letters, P < 0.001; 24 months = 8.12 letters, P < 0.001) and anatomically (12-month CMT WMD = –114.12 μm, P < 0.001; 24 months = –90.4 μm, P = 0.004). Compared to bevacizumab, aflibercept was noninferior at improving BCVA at 12 months (WMD = 1.71 letters, P = 0.34) and 24 months (WMD = 1.58 letters, P = 0.083). One study found that aflibercept was more effective than bevacizumab anatomically at 1 and 2 years (P < 0.001 at 12 and 24 months). Compared to ranibizumab, aflibercept rendered a greater improvement in BCVA at 1 year (WMD = 1.76 letters, P = 0.001), but not 2 years (WMD = 1.66 letters, P = 0.072). CMT was not significantly different between both therapies at 12 months (WMD = −14.30 μm, P = 0.282) and 24 months (P = 0.08). One study reported greater functional improvement with aflibercept compared with dexamethasone (P = 0.004), but inferiority in reducing CMT (P < 0.001). Meta-regression analysis demonstrated that dosing schedule was found to impact outcomes at 12 and 24 months, while study design and sample size did not impact outcomes at 12 months. There were minimal safety concerns using aflibercept therapy.

Conclusions:

Aflibercept is a safe and effective therapy option for DME in the clinical setting, performing superiorly to laser photocoagulation. Evidence regarding comparisons with bevacizumab, ranibizumab, and dexamethasone is mixed and limited.

Subthreshold micropulse laser versus intravitreal anti-VEGF for diabetic macular edema patients with relatively better visual acuity

AIM

To compare the effects of yellow (577 nm) subthreshold micropulse laser (SML) and intravitreal (IV) anti-vascular endothelial growth factor (VEGF) treatment in patients with diabetic macular edema (DME) with relatively better visual acuity [best corrected visual acuity (BCVA) ≤0.15 logMAR].

METHODS

The medical records of 76 eyes of 47 patients underwent IV (0.5 mg) anti-VEGF injection or SML for the DME with relatively better BCVA were reviewed. The IV group received three consecutive monthly IV anti-VEGF injections, then were retreated as needed. The laser treatment group was treated at baseline and 3mo, and then retreated at 6 and 9mo if needed. All participants were followed up for one year. The mean BCVA and mean central macular thickness (CMT) values changes over the follow-up were evaluated.

RESULTS

Twenty-four and 23 patients were assigned to the SML and IV subgroups, respectively. The mean number of treatments was 3.64±0.76 in SML group and 5.85±1.38 in IV group (P<0.05). The subgroups were similar with regard to the mean BCVA score at baseline and at the 1^st and 3^rd months, but the score of SML group was better than that of IV group at the 6^th, 9^th, and 12^th months (P<0.05). The decrease in the mean CMT values from baseline values was higher in SML group at the 6^th, 9^th, and 12^th months (P<0.05).

CONCLUSION

Yellow SML treatment is superior to IV anti-VEGF injection in DME patients with relatively better BCVA for increasing visual acuity and decreasing CMT at 6, 9, and 12mo. SML can be a good alternative first-line therapy for DME with BCVA ≤0.15 logMAR.

Retinal laser services in Bhutan: a 3-year national survey

BACKGROUND

We conducted this study to report on the indications and types of retinal laser therapy (RLT) performed in Bhutan, knowing which is critical for proper planning and successful delivery of the services.

METHODS

We reviewed the laser registers maintained in the laser rooms and vitreoretinal (VR) operating theatres (including paediatric cases managed under anaesthesia) over three years at the national and the two regional referral hospitals (RRHs). Intraoperative laser treatments (endolaser) were excluded. Patient demography, indications and types of RLT were recorded and quantified. Comparisons of the expected and observed frequencies used Chi-squared tests.

RESULTS

A total of 685 patients, including 8 cases of bilateral retinopathy of prematurity (ROP) received RLT. The majority of patients (411 cases, 60.0%, p < 0.0001) were males. The mean age was 54.1 ± 14.1 years, median 56 years. The most common indications for RLT were diabetic retinopathy (DR) and diabetic macular oedema (DMO) (542 cases, 66.0%), followed by retinal vein occlusion (RVO) (91 cases, 13.3%). Pan-retinal photocoagulation was the most common type of RLT performed (337 cases, 49.2%), followed by modified grid laser (207 cases, 30.2%), sectoral laser (41 cases, 6.0%), and prophylactic laser photocoagulation (33 cases, 4.8%).

CONCLUSIONS

The majority of patients were within working-age. Common indications for RLT were preventable such as DR, DMO and RVO, indicating need to control systemic diseases such as diabetes, hypertension, and dyslipidaemia. Currently, regular RLT is provided only at the national referral hospital in Thimphu, and periodically in the eastern and central RRHs when the retinal specialist visits. There is need to extend the retinal services to the eastern and central RRHs to improve accessibility and patient coverage in these regions challenged with difficult terrain and poor public transport system.

Cost-effectiveness analysis of intravitreal aflibercept in the treatment of diabetic macular edema in China

Aim: To evaluate the cost-effectiveness of intravitreal aflibercept compared with macular laser photocoagulation and ranibizumab for diabetic macular edema (DME) in China. Methods: A Markov model was developed to reflect the vision changes in DME patients. Parameters were estimated from VIVID-EAST trial data, published literature and physician surveys. Results: In a 20-year horizon, intravitreal aflibercept was associated with 7.825 quality-adjusted life years (QALYs) and 217,841 Chinese Yuan Renminbi (CNY), laser photocoagulation was associated with 7.189 QALYs and 135,489 CNY, and ranibizumab was associated with 7.462 QALYs and 222,477 CNY. The incremental cost-effectiveness ratios were 129,397 CNY/QALY and -12,774 CNY/QALY for intravitreal aflibercept versus laser photocoagulation and ranibizumab, respectively. Conclusion: Intravitreal aflibercept was considered as a cost-effective strategy for DME when compared with laser photocoagulation; it was considered as a dominant strategy when compared with ranibizumab.

Cost Effectiveness of Treatments for Diabetic Retinopathy: A Systematic Literature Review

BACKGROUND

Diabetic retinopathy (DR) affects approximately one-third of people diagnosed with diabetes, can be sight-threatening, and generates significant human and economic burden. Over the last 2 decades, newer therapies have emerged, offering significant clinical benefits, however at a cost. Given the scarcity of available budgets, the cost effectiveness of these newer treatments is of vital importance to policy makers.

METHODS

A systematic review was conducted in the PubMed, EMBASE, Cochrane, HEED and CRD databases to find and evaluate economic evaluations assessing the cost effectiveness of alterative DR treatments. Studies were assessed for their eligibility, findings and quality, and are presented in this systematic review.

RESULTS

Of the 5254 studies retrieved from the literature search, 17 were included in this review. For patients with proliferative DR, when early pars plana vitrectomy was compared with pan-retinal laser photocoagulation, similar cost per quality-adjusted life-year (QALY) was observed between the two. Treatment with either intravitreal ranibizumab (IVR) or intravitreal bevacizumab (IVB) falls within acceptable cost-effectiveness thresholds in the diabetic macular oedema (DMO) population; however, in the non-DMO population, the marginal benefit of IVR or IVB in relation to the marginal cost relative to laser does not justify their use. Among the anti-vascular endothelial growth factor (VEGF) therapies, IVB appears more attractive from an economic point of view due to its lower cost. For patients with DMO, studies indicate that a combination therapy of IVR or IVB with laser and, to a lesser degree, as monotherapy, are cost effective relative to laser monotherapy; IVR plus laser is cost effective relative to laser plus triamcinolone; and laser combined with triamcinolone injections is reportedly more cost effective over IVR for pseudophakic eyes only. Moreover, fluocinolone implants appear cost effective compared with sham implants, or when treating refractory DMO. IVR administered either pro re nata (PRN) or as 'treat and extend' dominated intravitreal aflibercept (IVA) in a few studies. On the other hand, IVR monotherapy or with laser (as well as IVA) does not compare favourably relative to IVB monotherapy or with laser.

CONCLUSIONS

Interpretation of cost-effectiveness data should be treated with caution in this case; details of the therapeutic regimen, such as dosage and frequency, and clinical efficacy of the treatments should be considered in relation to policy-making decisions. Given the scarcity of resources, the ever-increasing significance of health technology assessment, and the substantial differences in the methodologies of the studies presented in this review, there is a pressing need for more advanced and standardised approaches to assessing the effectiveness and cost effectiveness of the emerging anti-VEGF pharmacotherapies for the treatment of DMO.

Dexamethasone Implant in Patients with Diabetic Macular Edema Resistant to Anti-VEGF Therapy

Objectives:

To investigate the efficacy of single dose intravitreal dexamethasone implant in patients with diabetic macular edema (DME) resistant to anti-VEGF therapy.

Materials and Methods:

Twenty eyes of 14 patients (8 male, 6 female; mean age, 65±5.7 years) with DME resistant to intravitreal ranibizumab injections were studied. A single intravitreal dexamethasone implant was injected into each eye and patients were followed up for 6 months. Response to therapy was assessed monthly by measuring intraocular pressure (IOP), best-corrected visual acuity (BCVA), and central foveal thickness (CFT).

Results:

Baseline (before injection) IOP was 14.9±2.7 mmHg and did not change significantly in the six months following injection. Baseline BCVA was 1.04±0.35 LogMAR and improved to 0.86±0.31 at month 1 without statistical significance (p=0.056). CFT was significantly lower in all monthly measurements compared to its baseline value of 682.2±229.2 μm. During the follow-up period, endophthalmitis, significant cataract, or rhegmatogenous retinal detachment were not detected.

Conclusion:

Intravitreal dexamethasone implant injection is associated with significant CFT reduction for up to six months without causing any complications. Although BCVA did not improve in parallel with the CFT reduction, intravitreal dexamethasone implant should be considered as an effective and safe treatment option in the management of DME patients resistant to anti-VEGF injections.

Impacto orçamentário da incorporação de medicamentos para tratamento em segunda linha do edema macular diabético no SUS sob a perspectiva da Secretaria de Estado de Saúde de Minas Gerais, Brasil

Resumo: Os objetivos foram efetuar a análise do impacto orçamentário para a incorporação de segunda linha terapêutica com terapia antiangiogênica de aplicação intravítrea, para tratamento de edema macular diabético, no âmbito do Sistema Único de Saúde (SUS) em Minas Gerais, Brasil, discutindo sua viabilidade à luz do orçamento do estado. A análise do impacto orçamentário com método determinístico, segundo diretriz do Ministério da Saúde. Foram incluídos os pacientes com provável falha ao tratamento de primeira linha, num horizonte temporal de 5 anos para todas as tecnologias avaliadas. Incluíram-se na análise os medicamentos bevacizumabe (uso off-label), ranibizumabe e aflibercepte. As populações foram calculadas tanto por demanda aferida quanto por estimativa epidemiológica. Como análises de sensibilidade efetuaram-se: cenário com difusão de tecnologia mais lenta; cenário com a entrada de bevacizumabe e ranibizumabe biossimilares no mercado; cenário com a desconsideração da inflação no período. O impacto orçamentário incremental, de acordo com as estimativas de demanda aferida e epidemiológica, respectivamente, foi de R$ 69.493.906,95-R$ 473.226.278,78 para bevacizumabe; R$ 349.319.965,60-R$ 2.378.732.103,09 para ranibizumabe e R$543.867.485,47-R$ 3.703.524.490,16 para aflibercepte. Bevacizumabe foi a alternativa financeiramente mais viável em todos os cenários das estimativas e análises de sensibilidade. Estimou-se incremento próximo a 3%, comparando com o orçamento de 2016 (demanda aferida). Avalia-se que a incorporação é viável dentro do SUS em Minas Gerais, mas sujeita às prioridades da gestão. A discrepância de preços entre produtos de eficácia semelhante é intrigante e tema fértil para estudos futuros.

An efficacy comparison of anti-vascular growth factor agents and laser photocoagulation in diabetic macular edema: a network meta-analysis incorporating individual patient-level data

BACKGROUND

This was an updated network meta-analysis (NMA) of anti-vascular endothelial growth factor (VEGF) agents and laser photocoagulation in patients with diabetic macular edema (DME). Unlike previous NMA that used meta-regression to account for potential confounding by systematic variation in treatment effect modifiers across studies, this update incorporated individual patient-level data (IPD) regression to provide more robust adjustment.

METHODS

An updated review was conducted to identify randomised controlled trials for inclusion in a Bayesian NMA. The network included intravitreal aflibercept (IVT-AFL) 2 mg bimonthly (2q8) after 5 initial doses, ranibizumab 0.5 mg as-needed (PRN), ranibizumab 0.5 mg treat-and-extend (T&E), and laser photocoagulation. Outcomes included in the analysis were change in best-corrected visual acuity (BCVA), measured using an Early Treatment Diabetic Retinopathy Study (ETDRS) chart, and patients with ≥10 and ≥ 15 ETDRS letter gains/losses at 12 months. Analyses were performed using networks restricted to IPD-only and IPD and aggregate data with (i) no covariable adjustment, (ii) covariable adjustment for baseline BVCA assuming common interaction effects (against reference treatment), and (iii) covariable adjustments specific to each treatment comparison (restricted to IPD-only network).

RESULTS

Thirteen trials were included in the analysis. IVT-AFL 2q8 was superior to laser in all analyses. IVT-AFL 2q8 showed strong evidence of superiority (95% credible interval [CrI] did not cross null) versus ranibizumab 0.5 mg PRN for mean change in BCVA (mean difference 5.20, 95% CrI 1.90-8.52 ETDRS letters), ≥15 ETDRS letter gain (odds ratio [OR] 2.30, 95% CrI 1.12-4.20), and ≥10 ETDRS letter loss (OR 0.25, 95% CrI 0.05-0.74) (IPD and aggregate random-effects model with baseline BCVA adjustment). IVT-AFL 2q8 was not superior to ranibizumab 0.5 mg T&E for mean change in BCVA (mean difference 5.15, 95% CrI -0.26-10.61 ETDRS letters) (IPD and aggregate random-effects model).

CONCLUSIONS

This NMA, which incorporated IPD to improve analytic robustness, showed evidence of superiority of IVT-AFL 2q8 to laser and ranibizumab 0.5 mg PRN. These results were irrespective of adjustment for baseline BCVA.

Anti-vascular endothelial growth factor for diabetic macular oedema: a network meta-analysis

BACKGROUND

Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) can reduce oedema, improve vision and prevent further visual loss. These drugs have replaced laser photocoagulation as the standard of care for people with DMO.

OBJECTIVES

The 2014 update of this review found high-quality evidence of benefit with anti-VEGF modalities, compared to laser photocoagulation, for the treatment of DMO. The objective of this updated review is to compare the effectiveness and safety of the different anti-VEGF drugs using network meta-analysis methods.

SEARCH METHODS

We searched various electronic databases on 26 April 2017.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for pair-wise meta-analysis and we augmented this evidence using network meta-analysis methods. We focused on the relative efficacy and safety of the three most commonly used drugs as interventions of direct interest for practice: aflibercept and ranibizumab, used on-label; and off-label bevacizumab.We collected data on three efficacy outcomes (gain of 15 or more Early Treatment Diabetic Retinopathy Study (ETDRS) letters; mean change in best-corrected visual acuity (BCVA); mean change in central retinal thickness (CRT)), three safety outcomes (all severe systemic adverse events (SSAEs); all-cause death; arterial thromboembolic events) and quality of life.We used Stata 'network' meta-analysis package for all analyses. We investigated the risk of bias of mixed comparisons based on the variance contribution of each study, having assigned an overall risk of bias to each study.

MAIN RESULTS

Twenty-four studies included 6007 participants with DMO and moderate vision loss, of which two studies randomised 265 eyes of 230 participants and one was a cross-over study on 56 participants (62 eyes) that was treated as a parallel-arm trial. Data were collected on drugs of direct interest from three studies on aflibercept (975 eyes), eight studies on bevacizumab (515 eyes), and 14 studies on ranibizumab (1518 eyes). As treatments of indirect interest or legacy treatment we included three studies on pegaptanib (541 eyes), five studies on ranibizumab plus prompt laser (557 eyes), one study on ranibizumab plus deferred laser (188 eyes), 13 studies on laser photocoagulation (936 eyes) and six studies on sham treatment (793 eyes).Aflibercept, bevacizumab and ranibizumab were all more effective than laser for improving vision by 3 or more lines after one year (high-certainty evidence). Approximately one in 10 people improve vision with laser, and about three in 10 people improve with anti-VEGF treatment: risk ratio (RR) versus laser 3.66 (95% confidence interval (CI) 2.79 to 4.79) for aflibercept; RR 2.47 (95% CI 1.81 to 3.37) for bevacizumab; RR 2.76 (95% CI 2.12 to 3.59) for ranibizumab. On average there was no change in visual acuity (VA) with laser after one year, compared with a gain of 1 or 2 lines with anti-VEGF treatment: laser versus aflibercept mean difference (MD) -0.20 (95% CI -0.22 to -0.17) logMAR; versus bevacizumab MD -0.12 (95% CI -0.15 to -0.09) logMAR; versus ranibizumab MD -0.12 (95% CI -0.14 to -0.10) logMAR. The certainty of the evidence was high for the comparison of aflibercept and ranibizumab with laser and moderate for bevacizumab comparison with laser due to inconsistency between the indirect and direct evidence.People receiving ranibizumab were less likely to gain 3 or more lines of VA at one year compared with aflibercept: RR 0.75 (95% CI 0.60 to 0.94), moderate-certainty evidence. For every 1000 people treated with aflibercept, 92 fewer would gain 3 or more lines of VA at one year if treated with ranibizumab (22 to 148 fewer). On average people receiving ranibizumab had worse VA at one year (MD 0.08 logMAR units, 95% CI 0.05 to 0.11), moderate-certainty evidence; and higher CRT (MD 39 µm, 95% CI 2 µm to 76 µm; low-certainty evidence). Ranibizumab and bevacizumab were comparable with respect to aflibercept and did not differ in terms of VA: RR of gain of 3 or more lines of VA at one year 1.11 (95% CI 0.87 to 1.43), moderate-certainty evidence, and difference in change in VA was 0.00 (95% CI -0.02 to 0.03) logMAR, moderate-certainty evidence. CRT reduction favoured ranibizumab by -29 µm (95% CI -58 µm to -1 µm, low-certainty evidence). There was no evidence of overall statistical inconsistency in our analyses.The previous version of this review found moderate-certainty evidence of good safety of antiangiogenic drugs versus control. This update used data at the longest available follow-up (one or two years) and found that aflibercept, ranibizumab and bevacizumab do not differ regarding systemic serious adverse events (SSAEs) (moderate- or high-certainty evidence). However, risk of bias was variable, loop inconsistency could be found and estimates were not precise enough on relative safety regarding less frequent events such as arterial thromboembolic events or death (low- or very low-certainty evidence).Two-year data were available and reported in only four RCTs in this review. Most industry-sponsored studies were open-label after one year. One large publicly-funded study compared the three drugs at two years and found no difference.

AUTHORS' CONCLUSIONS

Anti-VEGF drugs are effective at improving vision in people with DMO with three to four in every 10 people likely to experience an improvement of 3 or more lines VA at one year. Aflibercept may confer some advantage over ranibizumab and bevacizumab in people with DMO at one year in visual and anatomic terms but it is unclear whether this applies to the long-term. There is a need for more evidence on the long-term (greater than two years) comparative effects of these anti-VEGF agents. Evidence from RCTs may not apply to real-world practice, where people in need of antiangiogenic treatment are often under-treated and under-monitored.We found no signals of differences in overall safety between the three antiangiogenic drugs that are currently available to treat DMO, but our estimates are imprecise for cardiovascular events and death.

Evaluation of markers of outcome in real-world treatment of diabetic macular edema

Objective

To evaluate short-term markers of outcome in diabetic macular edema (DME).

Methods

Prospective interventional case series included 122 eyes of 122 patients with recently diagnosed DME. Eyes were treated with a 3-monthly loading dose of ranibizumab or aflibercept and pro re nata thereafter. Serial enhanced deep imaging SD-OCT high resolution scans were used to measure subfoveal choroidal thickness (SFCT) and central retinal thickness (CRT). Anatomic (10% CRT decrease) and functional responses (best corrected visual acuity, BCVA gain ≥5 letters) were assessed at 3 months and 6 months using univariate and multivariate analyses. Parameters tested were gender, duration of diabetes, HbA1c, hypertension, CRT, SFCT, BCVA, ellipsoid zone (EZ) status, subfoveal neuroretinal detachment (SND), anti-VEGF used and laser naivety. A logistic regression model was applied to find independent markers outcome.

Results

BCVA increased, CRT and SFCT decreased at 3 months and 6 months. Good metabolic control (p = 0.003), intact baseline EZ (p = 0.030), EZ re-grading at 3 M (p < 0.001) and laser naivety (p = 0.001) were associated with better functional outcome. The multivariate linear regression model showed that baseline SND and CRT are predictors of anatomic response, while lower baseline BCVA and intact EZ are predictors of functional response.

Conclusion

The presence of SND predicts anatomic response only, while an intact EZ is critical to achieve a good functional outcome in DME.

Electronic supplementary material

The online version of this article (10.1186/s40662-018-0119-9) contains supplementary material, which is available to authorized users.

In Vivo Study of the Long Term Structural Changes Induced by Macular Argon Laser

PURPOSE

To assess the long-term structural changes induced by macular argon laser using en face optical coherence tomography (OCT).

MATERIALS AND METHODS

We reviewed the charts and OCT pictures of patients who had undergone macular laser for diabetic macular edema at least four years ago. Clinical parameters were recorded for each eye, including laser settings. We obtained En face pictures, that were flattened at the RPE (retinal pigment epithelium) plane. We then measured the retinal surface covered by laser marks and the maximal diameter of the largest identified lesion at this plane.  The most superficial level of neurosensory retinal damage as well as the total retinal thickness at this location were measured from the RPE. We also measured the distance between the RPE and the deeper plane at which laser marks were detected.

RESULTS

21 eyes of 16-patients were analyzed. The mean age (±SD) was 61.7 ± 15.5 years. Patients had undergone macular laser 6.5 ± 2.8 years prior to entering our study.  In 16 eyes the most superficial laser marks were detected at the inner plexiform/inner nuclear layers. The level of neurosensory retinal damage was 159 ± 48 microns over the RPE (62.6 ± 18.3% of the retinal thickness). The deepest level at which laser marks were retrieved was 125 ± 110 microns below the RPE.  The growth of laser marks was correlated to time (Pearson's correlation coefficient = 0.23; p = 0.1).

CONCLUSIONS

Argon laser marks gradually expand in the horizontal and vertical axes. The damage induced by argon laser in the neurosensory retina often reaches inner layers.

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).

Inhibition of Stat3 by a Small Molecule Inhibitor Slows Vision Loss in a Rat Model of Diabetic Retinopathy

Purpose

Diabetic retinopathy is a leading cause of vision loss. Previous studies have shown signaling pathways mediated by Stat3 (signal transducer and activator of transcription 3) play a primary role in diabetic retinopathy progression. This study tested CLT-005, a small molecule inhibitor of Stat3, for its dose-dependent therapeutic effects on vision loss in a rat model of diabetic retinopathy.

Methods

Brown Norway rats were administered streptozotocin (STZ) to induce diabetes. CLT-005 was administered daily by oral gavage for 16 weeks at concentrations of 125, 250, or 500 mg/kg, respectively, beginning 4 days post streptozotocin administration. Systemic and ocular drug concentration was quantified with mass spectrometry. Visual function was monitored at 2-week intervals from 6 to 16 weeks using optokinetic tracking to measure visual acuity and contrast sensitivity. The presence and severity of cataracts was visually monitored and correlated to visual acuity. The transcription and translation of multiple angiogenic factors and inflammatory cytokines were measured by real-time polymerase chain reaction and Multiplex immunoassay.

Results

Streptozotocin-diabetic rats sustain progressive vision loss over 16 weeks, and this loss in visual function is rescued in a dose-dependent manner by CLT-005. This positive therapeutic effect correlates to the positive effects of CLT-005 on vascular leakage and the presence of inflammatory cytokines in the retina.

Conclusions

The present study indicates that Stat3 inhibition has strong therapeutic potential for the treatment of vision loss in diabetic retinopathy.

Anti-vascular endothelial growth factor for diabetic macular oedema: a network meta-analysis

BACKGROUND

Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) modalities can reduce oedema and thereby improve vision and prevent further visual loss. These drugs have replaced laser photocoagulation as the standard of care for people with DMO.

OBJECTIVES

The 2014 update of this review found high-quality evidence of benefit with antiangiogenic therapy with anti-VEGF modalities, compared to laser photocoagulation, for the treatment of DMO.The objective of this updated review is to compare the effectiveness and safety of the different anti-VEGF drugs in preserving and improving vision and quality of life using network meta-analysis methods.

SEARCH METHODS

We searched various electronic databases on 26 April 2017.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for pair-wise meta-analysis and we augmented this evidence using network meta-analysis methods. We focused on the relative efficacy and safety of the three most commonly used drugs as interventions of direct interest for practice: aflibercept and ranibizumab, used on-label; and off-label bevacizumab.We collected data on three efficacy outcomes (gain of 15 or more Early Treatment Diabetic Retinopathy Study (ETDRS) letters; mean change in best-corrected visual acuity (BCVA); mean change in central retinal thickness (CRT)), three safety outcomes (all severe systemic adverse events (SSAEs); all-cause death; arterial thromboembolic events) and quality of life.We used Stata 'network' meta-analysis package for all analyses. We investigated the risk of bias of mixed comparisons based on the variance contribution of each study, having assigned an overall risk of bias to each study.

MAIN RESULTS

Twenty-four studies included 6007 participants with DMO and moderate vision loss, of which two studies randomised 265 eyes of 230 participants and one was a cross-over study on 56 participants (62 eyes) that was treated as a parallel-arm trial. Data were collected on drugs of direct interest from three studies on aflibercept (975 eyes), eight studies on bevacizumab (515 eyes), and 14 studies on ranibizumab (1518 eyes). As treatments of indirect interest or legacy treatment we included three studies on pegaptanib (541 eyes), five studies on ranibizumab plus prompt laser (557 eyes), one study on ranibizumab plus deferred laser (188 eyes), 13 studies on laser photocoagulation (936 eyes) and six studies on sham treatment (793 eyes).Aflibercept, bevacizumab and ranibizumab were all more effective than laser for improving vision by 3 or more lines after one year (high-certainty evidence). Approximately one in 10 people improve vision with laser, and about three in 10 people improve with anti-VEGF treatment: risk ratio (RR) versus laser 3.66 (95% confidence interval (CI) 2.79 to 4.79) for aflibercept; RR 2.47 (95% CI 1.81 to 3.37) for bevacizumab; RR 2.76 (95% CI 2.12 to 3.59) for ranibizumab. On average there was no change in visual acuity (VA) with laser after one year, compared with a gain of 1 or 2 lines with anti-VEGF treatment: laser versus aflibercept mean difference (MD) -0.20 (95% CI -0.22 to -0.17) logMAR; versus bevacizumab MD -0.12 (95% CI -0.15 to -0.09) logMAR; versus ranibizumab MD -0.12 (95% CI -0.14 to -0.10) logMAR. The certainty of the evidence was high for the comparison of aflibercept and ranibizumab with laser and moderate for bevacizumab comparison with laser due to inconsistency between the indirect and direct evidence.People receiving ranibizumab were less likely to gain 3 or more lines of VA at one year compared with aflibercept: RR 0.75 (95% CI 0.60 to 0.94), moderate-certainty evidence. For every 1000 people treated with aflibercept, 92 fewer would gain 3 or more lines of VA at one year if treated with ranibizumab (22 to 148 fewer). On average people receiving ranibizumab had worse VA at one year (MD 0.08 logMAR units, 95% CI 0.05 to 0.11), moderate-certainty evidence; and higher CRT (MD 39 µm, 95% CI 2 µm to 76 µm; low-certainty evidence). Ranibizumab and bevacizumab were comparable with respect to aflibercept and did not differ in terms of VA: RR of gain of 3 or more lines of VA at one year 1.11 (95% CI 0.87 to 1.43), moderate-certainty evidence, and difference in change in VA was 0.00 (95% CI -0.02 to 0.03) logMAR, moderate-certainty evidence. CRT reduction favoured ranibizumab by -29 µm (95% CI -58 µm to -1 µm, low-certainty evidence). There was no evidence of overall statistical inconsistency in our analyses.The previous version of this review found moderate-certainty evidence of good safety of antiangiogenic drugs versus control. This update used data at the longest available follow-up (one or two years) and found that aflibercept, ranibizumab and bevacizumab do not differ regarding systemic serious adverse events (SSAEs) (moderate- or high-certainty evidence). However, risk of bias was variable, loop inconsistency could be found and estimates were not precise enough on relative safety regarding less frequent events such as arterial thromboembolic events or death (low- or very low-certainty evidence).Two-year data were available and reported in only four RCTs in this review. Most industry-sponsored studies were open-label after one year. One large publicly-funded study compared the three drugs at two years and found no difference.

AUTHORS' CONCLUSIONS

Anti-VEGF drugs are effective at improving vision in people with DMO with three to four in every 10 people likely to experience an improvement of 3 or more lines VA at one year. There is moderate-certainty evidence that aflibercept confers some advantage over ranibizumab and bevacizumab in people with DMO at one year in visual and anatomic terms. Relative effects among anti-VEGF drugs at two years are less well known, since most studies were short term. Evidence from RCTs may not apply to real-world practice, where people in need of antiangiogenic treatment are often under-treated and under-monitored.We found no signals of differences in overall safety between the three antiangiogenic drugs that are currently available to treat DMO, but our estimates are imprecise for cardiovascular events and death.

Update on Diagnosis and Treatment of Diabetic Retinopathy: A Consensus Guideline of the Working Group of Ocular Health (Spanish Society of Diabetes and Spanish Vitreous and Retina Society)

A group of members of the Spanish Retina and Vitreous Society (SERV) and of the Working Group of Ocular Health of the Spanish Society of Diabetes (SED) updated knowledge regarding the diagnosis and treatment of diabetic retinopathy (DR) based on recent evidence reported in the literature. A synthesis of this consensus forms the basis of the present review, which is intended to inform clinicians on current advances in the field of DR and their clinical applicability to patients with this disease. Aspects presented in this article include screening procedures of DR, new technologies in the early diagnosis of DR, control of risk factors in the different stages of the disease, indications of panretinal laser photocoagulation, efficacy of intravitreal antiangiogenic agents and steroids, and surgical options for treating DR-related complications. Practical information regarding periodicity of screening procedures in patients with type 1 and type 2 diabetes, ophthalmological controls according to the stage of retinopathy and complications, and criteria and degree of urgency for referral of a DR patient to the ophthalmologist are also presented.

Comparison of subthreshold diode laser micropulse therapy versus conventional photocoagulation laser therapy as primary treatment of diabetic macular edema

PURPOSE

The aim of the present study was to investigate the effect of subthreshold diode laser micropulse (SDM) in comparison with conventional laser photocoagulation in the treatment of the diabetic macular edema (DME).

METHODS

Sixty-eight eyes from 68 patients with clinically significant DME were divided randomly into two equal groups. In the first group, SDM photocoagulation was employed, while conventional laser photocoagulation was performed on the eyes of the second group. Central macular thickness (CMT), central macular volume (CMV), and best corrected visual acuity (BCVA) were measured before, 2, and 4 months after intervention, and the results were compared.

RESULTS

The mean CMT was 357.3 and 354.8 microns before the treatment in Groups 1 and 2, respectively (P = 0.85), and decreased significantly to 344.3 and 349.8 after 4 months, respectively (P = 0.012 and P = 0.049). The changes in the central macular thickness was statistically higher in the first group (P = 0.001). The mean CMV significantly decreased in Group 1 (P = 0.003), but it was similar to pretreatment in Group 2 after 4 months (P = 0.31). The BCVA improved significantly in Group 1 (P < 0.001), but it remained unchanged in Group 2 (P = 0.38).

CONCLUSIONS

In this study, SDM was more effective than conventional laser photocoagulation in reducing CMT and CMV and improving visual acuity in patients with DME.

Aflibercept: A Review of Its Use in the Management of Diabetic Eye Complications

Aflibercept is the most recently approved vascular endothelial growth factor (anti-VEGF) inhibitor for the management of diabetic macular edema and diabetic retinopathy. The purpose of this article is to review the efficacy and safety of aflibercept in the management of diabetic eye complications and to describe its place in therapy. Anti-VEGF agents have been noted in clinical trials to be superior to laser photocoagulation, the standard therapy ( P < .0001, P ≤ .0085, respectively). Aflibercept has been comparatively studied with other anti-VEGF agents, namely, bevacizumab and ranibizumab, and noted to be equally efficacious and safe in patients with mild visual acuity loss ( P > .50). However, in the treatment of patients with diabetic macular edema having moderate to severe visual acuity loss, aflibercept outperformed the other 2 anti-VEGF agents (aflibercept vs bevacizumab, P < .001; aflibercept vs ranibizumab, P = .003). However, additional studies are needed to fully appreciate the long-term safety and efficacy of aflibercept and the anti-VEGF therapy class.

Retinal fibrosis in diabetic retinopathy

In response to injury, reparative processes are triggered to restore the damaged tissue; however, such processes are not always successful in rebuilding the original state. The formation of fibrous connective tissue is known as fibrosis, a hallmark of the reparative process. For fibrosis to be successful, delicately balanced cellular events involving cell proliferation, cell migration, and extracellular matrix (ECM) remodeling must occur in a highly orchestrated manner. While successful repair may result in a fibrous scar, this often restores structural stability and functionality to the injured tissue. However, depending on the functionality of the injured tissue, a fibrotic scar can have a devastating effect. For example, in the retina, fibrotic scarring may compromise vision and ultimately lead to blindness. In this review, we discuss some of the retinal fibrotic complications and highlight mechanisms underlying the development of retinal fibrosis in diabetic retinopathy.

Cost-utility of ranibizumab versus aflibercept for treating Greek patients with visual impairment due to diabetic macular edema

Background

To conduct a cost-utility analysis of ranibizumab versus aflibercept for the treatment of patients with visual impairment due to diabetic macular edema (DME) in the Greek setting.

Methods

A Markov model was adapted to compare the use of ranibizumab 0.5 mg (pro re nata-PRN and treat and extend-T&E) to aflibercept 2 mg (every 8 weeks after five initial doses) in DME. Patients transitioned at a 3-month cycle among nine specified health states (including death) over a lifetime horizon. Transition probabilities, utilities, as well as DME-related mortality were extracted from relevant clinical trials, a network meta-analysis and other published studies. The analysis was conducted from payer perspective and as such only costs reimbursed by the payer were considered (year 2014). The incremental cost per quality-adjusted life year (QALY) gained and the net monetary benefit was the main outcome measures.

Results

Τhe use of PRN and T&E ranibizumab regimens were shown to be cost saving comparing to aflibercept (by €2824 and €22, respectively), and more beneficial in terms of QALYs gained (+0.05) and time without visual impairment (0.031 and 0.034 years), thereby dominating aflibercept. Moreover, ranibizumab used as PRN or T&E resulted in a net monetary benefit of €3984 and €1278, respectively.

Conclusions

Both PRN and T&E ranibizumab regimens were more beneficial and less costly compared to aflibercept for the management of DME. Hence, ranibizumab seems to be a dominant option for the treatment of visual impairment due to DME in the Greek setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s12962-016-0056-1) contains supplementary material, which is available to authorized users.

Using Patient-Level Data to Develop Meaningful Cross-Trial Comparisons of Visual Impairment in Individuals with Diabetic Macular Edema

INTRODUCTION

The aim of this study was to assess the impact of baseline characteristics on visual outcome of patients with diabetic macular edema and compare the results of clinical trials with different patient populations.

METHODS

A model was created with patient-level data from the RESPOND/RESTORE trials to estimate the impact of baseline characteristics on increases in best-corrected visual acuity (BCVA) with anti-vascular endothelial growth factor therapies, measured by letters gained on the Early Treatment Diabetic Retinopathy Study scale from baseline to month 12. Mean BCVA gains with ranibizumab 0.5 mg pro re nata or laser photocoagulation monotherapy were predicted, assuming baseline characteristics equivalent to those in the VIVID-DME/VISTA-DME trials. These results were compared with the gain with aflibercept 2.0 mg every 8 weeks in VIVID-DME/VISTA-DME. Sensitivity analyses assessed outcome robustness.

RESULTS

Baseline BCVA and central retinal thickness differed significantly between trials. In unadjusted data, patients in RESPOND/RESTORE receiving ranibizumab gained an additional 6.6 letters [95% confidence interval (CI): 4.5-8.7] compared with patients receiving laser monotherapy. After adjusting data to assume baseline characteristics equivalent to VIVID-DME/VISTA-DME, patients receiving ranibizumab were predicted to gain an additional 9.9 letters (95% CI: 7.3-12.4) compared with those receiving laser monotherapy. These results were similar (0.1-letter difference in favor of aflibercept; 95% CI: -2.9 to 3.2; P = 0.94) to the gain in BCVA in patients receiving aflibercept in VIVID-DME/VISTA-DME compared with those receiving laser monotherapy (10.0 letters, 95% CI: 8.3-11.7).

CONCLUSION

After adjusting for baseline characteristics, the difference in letters gained between patients receiving ranibizumab versus aflibercept was non-significant across trials, highlighting the importance of adjusting for baseline characteristics in future comparisons.

FUNDING

Novartis Pharma AG.

Effects of intravitreal ranibizumab on the untreated eye and systemic gene expression profile in age-related macular degeneration

The purpose of this study was to evaluate the systemic effects of intravitreal ranibizumab (Lucentis) treatment in patients with neovascular age-related macular degeneration (AMD). The impact of intravitreal ranibizumab injections on central retinal thickness (CRT) of treated and contralateral untreated eyes, and differences in gene expression patterns in the peripheral blood mononuclear cells were analyzed. The study included 29 patients aged 50 years old and over with diagnosed neovascular AMD. The treatment was defined as 0.5 mg of ranibizumab injected intravitreally in the form of one injection every month during the period of 3 months. CRT was measured by optical coherence tomography. The gene expression profile was assigned using oligonucleotide microarrays of Affymetrix HG-U133A. Studies have shown that there was a change of CRT between treated and untreated eyes, and there were differences in CRT at baseline and after 1, 2, and 3 months of ranibizumab treatment. Three months after intravitreal injection, mean CRT was reduced in the treated eyes from 331.97±123.62 to 254.31±58.75 μm, while mean CRT in the untreated fellow eyes reduced from 251.07±40.29 to 235.45±36.21 μm at the same time. Furthermore, the research has shown that among all transcripts, 3,097 expresses change after the ranibizumab treatment in relation to controls. Among these transcripts, 1,339 were up-regulated, whereas 1,758 were down-regulated. Our results show the potential systemic effects of anti-VEGF therapy for AMD. Moreover, our study indicated different gene expression in peripheral blood mononuclear cells before and after intravitreal ranibizumab treatment.

Diabetic retinopathy: intravitreal vascular endothelial growth factor inhibitors for diabetic macular oedema

INTRODUCTION

Diabetic retinopathy is the most common microvascular complication of diabetes. It is also the most common cause of blindness in working-age adults in industrialised nations. Older people and those with worse diabetes control, hypertension, and hyperlipidaemia are most at risk. Diabetic macular oedema, which can occur at any stage of diabetic retinopathy, is related to increased vascular permeability and breakdown of the blood retinal barrier, in part related to increased vascular endothelial growth factor (VEGF) levels. About 1% to 3% of people with diabetes suffer vision loss because of diabetic macular oedema.

METHODS AND OUTCOMES

We conducted a systematic overview, aiming to answer the following clinical questions: What are the effects of intravitreal VEGF inhibitors versus each other for diabetic macular oedema? What are the effects of intravitreal VEGF inhibitors plus laser therapy versus intravitreal VEGF inhibitors alone for diabetic macular oedema? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2014 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview).

RESULTS

At this update, searching of electronic databases retrieved 240 studies. After deduplication and removal of conference abstracts, 149 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 90 studies and the further review of 59 full publications. Of the 59 full articles evaluated, eight systematic reviews and four RCTs were added at this update. We performed a GRADE evaluation for four PICO combinations.

CONCLUSIONS

In this systematic overview, we categorised the efficacy for six comparisons based on information about the effectiveness and safety of intravitreal VEGF inhibitors aflibercept, bevacizumab, and ranibizumab, and each of these intravitreal VEGF inhibitors plus laser therapy.

Novel strategies for the treatment of diabetic macular edema

Macular edema such as diabetic macular edema (DME) and diabetic retinopathy are devastating back-of-the-eye retinal diseases leading to loss of vision. This area is receiving considerable medical attention. Posterior ocular diseases are challenging to treat due to complex ocular physiology and barrier properties. Major ocular barriers are static (corneal epithelium, corneal stroma, and blood-aqueous barrier) and dynamic barriers (blood-retinal barrier, conjunctival blood flow, lymph flow, and tear drainage). Moreover, metabolic barriers impede posterior ocular drug delivery and treatment. To overcome such barriers and treat back-of-the-eye diseases, several strategies have been recently developed which include vitreal drainage, laser photocoagulation and treatment with biologics and/or small molecule drugs. In this article, we have provided an overview of several emerging novel strategies including nanotechnology based drug delivery approach for posterior ocular drug delivery and treatment with an emphasis on DME.

Müller glia activation by VEGF-antagonizing drugs: An in vitro study on rat primary retinal cultures

The effects of the anti-Vascular Endothelial Growth Factor (VEGF) drugs ranibizumab and aflibercept were studied in Müller glia in primary mixed cultures from rat neonatal retina. Treatment with both agents induced activation of Müller glia, demonstrated by increased levels of Glial Fibrillary Acidic Protein. In addition, phosphorylated Extracellular-Regulated Kinase 1/2 (ERK 1/2) showed enhanced immunoreactivity in activated Müller glia. Treatment with aflibercept induced an increase in K(+) channel (Kir) 4.1 levels and both drugs upregulated Aquaporin 4 (AQP4) in activated Müller glia. The results show that VEGF-antagonizing drugs influence the homeostasis of Müller cells in primary retinal cultures, inducing an activated phenotype. Upregulation of Kir4.1 and AQP4 suggests that Müller glia activation following anti-VEGF drugs may not depict a detrimental gliotic reaction. Indeed, it could represent one of the mechanisms able to contribute to the therapeutic effects of these drugs, particularly in the presence of macular edema.

The clinical utility of aflibercept for diabetic macular edema

The treatment of center-involving diabetic macular edema (DME) has improved because of the proven efficacy of drugs that inhibit the effects of vascular endothelial growth factor (VEGF). The newest anti-VEGF drug, aflibercept, has recently been approved by the United States Food and Drug Administration for the treatment of center-involving DME and for diabetic retinopathy in eyes with DME. In the pivotal Phase III VISTA and VIVID trials, intravitreal aflibercept 2 mg injections every 4 or 8 weeks (after 5 monthly loading doses) produced superior gains in BCVA compared to laser/sham injections. In the Diabetic Retinopathy Clinical Research Network Protocol T trial, which featured monthly anti-VEGF monotherapy for 6 months, followed by monthly pro re nata anti-VEGF injections with laser rescue therapy from months 6 through 12, aflibercept 2 mg monthly was superior to bevacizumab 1.25 mg and ranibizumab 0.5 mg in eyes with BCVA of 20/50 or worse (aflibercept versus bevacizumab: P<0.001; aflibercept versus ranibizumab: P=0.003), but the three regimens were comparable for eyes with VA of 20/40 or better. Only in the 20/50 or worse subgroup did aflibercept achieve clinical superiority (>5 letter difference) to bevacizumab. Each treatment regimen led to significant macular thinning, with aflibercept being superior to bevacizumab in both visual acuity subgroups (P<0.001 for each), but it was not statistically superior to ranibizumab in either group. In diabetic patients, aflibercept has an excellent safety profile that does not appear to differ from laser/sham or other VEGF inhibitory drugs.

The progress in understanding and treatment of diabetic retinopathy

Diabetic retinopathy is the most frequently occurring complication of diabetes mellitus and remains a leading cause of vision loss globally. Its aetiology and pathology have been extensively studied for half a century, yet there are disappointingly few therapeutic options. Although some new treatments have been introduced for diabetic macular oedema (DMO) (e.g. intravitreal vascular endothelial growth factor inhibitors ('anti-VEGFs') and new steroids), up to 50% of patients fail to respond. Furthermore, for people with proliferative diabetic retinopathy (PDR), laser photocoagulation remains a mainstay therapy, even though it is an inherently destructive procedure. This review summarises the clinical features of diabetic retinopathy and its risk factors. It describes details of retinal pathology and how advances in our understanding of pathogenesis have led to identification of new therapeutic targets. We emphasise that although there have been significant advances, there is still a pressing need for a better understanding basic mechanisms enable development of reliable and robust means to identify patients at highest risk, and to intervene effectively before vision loss occurs.

The role of aflibercept in the management of diabetic macular edema

Diabetic macular edema (DME) represents one of the leading causes of visual impairment in working-age adults. Although there are several proven treatments available for this condition, pharmacotherapy through the use of intravitreal antivascular endothelial growth factor agents has revolutionized the management of DME over the past decade with superior outcomes compared to laser therapy. This review summarizes the pathophysiology and available treatment options for the management of DME, with an emphasis on the efficacy and safety profile of a single particular intravitreal antivascular endothelial growth factor agent, aflibercept.