Treatment of diabetic macular edema with sustained-release glucocorticoids: intravitreal triamcinolone acetonide, dexamethasone implant, and fluocinolone acetonide implant

Stigmast-4-en-3-one from Euonymus alatus (Thunb.) Siebold. improves diabetic retinopathy and angiogenesis mediated by glucocorticoids receptor

ETHNOPHARMACOLOGICAL RELEVANCE

Euonymus alatus (Thunb.) Siebold. (EA), a traditional Chinese medicine, is widely used in the treatment of diabetes. Our group has previously found that EA could treat diabetic retinopathy (DR) and stigmast-4-en-3-one (Numbered E6) is the active substance responsible for inhibiting angiogenesis in vitro by EA. However, the effects and mechanisms of E6 in the treatment of DR is still unknown.

AIM OF THE STUDY

The aim of this study was to investigate the effects and mechanisms of E6 in EA on DR. Additionally, a comparison was made between the effects of E6 and triamcinolone acetonide (TA), as well as the side effects of E6 and dexamethasone.

MATERIALS AND METHODS

Ocular affinity assessment and pharmacokinetic parameter prediction were conducted to evaluate the potential of E6 to treat DR. Retinal endothelial cells were used to investigate the in vitro inhibitory effect of E6 on vascular proliferation. Additionally, chicken embryos, zebrafish, and mice were used to investigate the in vivo anti-vascular proliferation effect of E6. Finally, diabetic mice were used to investigate whether E6 improves diabetic retinopathy and to compare its efficacy with that of TA. We then used network pharmacology to study the targets of E6 and performed molecular docking; followed by immunofluorescence experiments, ELISA, Western blot, and tube formation experiments to further investigate its mechanism. Finally, we compared the side effects of E6 with those of dexamethasone.

RESULTS

E6 was found to have an affinity for the eye and to inhibit vascular proliferation both in vivo and in vitro. Moreover, E6 was found to be more efficacious than TA in the treatment of DR. Molecular docking experiments predicted that the glucocorticoid receptor (GR) is a potential target of E6, and immunofluorescence analyses confirmed that E6 upregulated the expression of the GR in the retina of hyperglycemic mice. In addition, western blotting results and tube formation experiments showed that E6 also attenuated angiogenesis by inhibiting the Hippo and VEGF pathways. Finally, by comparing the effects of E6 and dexamethasone on glucose regulation and osteoporosis, E6 was found to have fewer side effects.

CONCLUSIONS

E6 is a highly effective drug for the treatment of DR, superior to TA and with fewer side effects than dexamethasone. Its mechanism involves the activation of glucocorticoid receptor and inhibition of Hippo and VEGF pathways to alleviate angiogenesis and inflammation. This study is the first to investigate the role and mechanism of E6 in improving DR. The findings suggest that E6 has unique advantages in the treatment of DR.

Intravitreal Dexamethasone Implant (Ozurdex) for Ocular Toxocariasis

This study aimed to evaluate the efficacy and safety of intravitreal dexamethasone implants in the treatment of ocular toxocariasis (OT). A retrospective analysis was performed on 6 cases in which laboratory tests diagnosed OT. All patients were administered with intravitreal dexamethasone implants with or without vitrectomy. The average follow-up time was 19.7 months. All operated eyes achieved anatomic success, and all patients' visual acuity was improved. Five of these six had a visual acuity of 20/100, and three had final acuity of 20/40 or even better. Intravitreal dexamethasone implants can be used to treat different types of OT, which not only effectively control inflammation and improve the patient's vision but also reduce the use of systemic glucocorticoids.

Diabetic Macular Oedema Guidelines: An Australian Perspective

The number of people living with diabetes is expected to rise to 578 million by 2030 and to 700 million by 2045, exacting a severe socioeconomic burden on healthcare systems around the globe. This is also reflected in the increasing numbers of people with ocular complications of diabetes (namely, diabetic macular oedema (DMO) and diabetic retinopathy (DR)). In one study examining the global prevalence of DR, 35% of people with diabetes had some form of DR, 7% had PDR, 7% had DMO, and 10% were affected by these vision-threatening stages. In many regions of the world (Australia included), DR is one of the top three leading causes of vision loss amongst working age adults (20-74 years). In the management of DMO, the landmark ETDRS study demonstrated that moderate visual loss, defined as doubling of the visual angle, can be reduced by 50% or more by focal/grid laser photocoagulation. However, over the last 20 years, antivascular endothelial growth factor (VEGF) and corticosteroid therapies have emerged as alternative options for the management of DMO and provided patients with choices that have higher chances of improving vision than laser alone. In Australia, since the 2008 NHMRC guidelines, there have been significant developments in both the treatment options and treatment schedules for DMO. This working group was therefore assembled to review and address the current management options available in Australia.

Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications

Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.

Multicenter, Prospective, Randomized Study of Dexamethasone Intravitreal Implant in Patients with Center-Involved Diabetic Macular Edema in the Asia-Pacific Region

Purpose

To evaluate the safety and efficacy of dexamethasone intravitreal implant 0.7 mg (DEX) compared with laser photocoagulation in patients with diabetic macular edema (DME).

Patients and Methods

This Phase 3, multicenter, randomized, efficacy evaluator–masked, parallel-group, 12-month clinical study enrolled adults in China and the Philippines with reduced visual acuity secondary to fovea-involved DME in the study eye. Participants were randomized 1:1 to study eye treatment with laser photocoagulation every 3 months as needed (n = 139) or DEX every 5 months (n = 145). The main efficacy measures were best-corrected visual acuity (BCVA), central retinal thickness (CRT), and leakage area. The primary endpoint was the average change in BCVA from baseline over 12 months (area-under-the-curve method). Preplanned subgroup analyses evaluated outcomes in Chinese patients.

Results

Mean average change in BCVA from baseline during the study (letters) was 4.3 with DEX (n = 145) versus 1.4 with laser (n = 127) overall (P = 0.001) and 4.6 with DEX (n = 129) versus 0.6 with laser (n = 113) in Chinese patients (P < 0.001). At Month 12, mean change in CRT from baseline was −209.5 μm with DEX versus −120.3 μm with laser (P < 0.001) and mean change in total leakage area from baseline was −8.367 mm² with DEX versus −0.637 mm² with laser (P < 0.001). The most common treatment-emergent adverse events in the DEX group were increased intraocular pressure and cataract.

Conclusion

DEX administered every 5 months provided significantly greater improvement in BCVA, CRT, and total leakage area compared with laser treatment. DEX demonstrated an acceptable safety profile, consistent with an intraocular corticosteroid, and similar to that reported in completed global registration studies.

Fluocinolone acetonide vitreous insert for chronic diabetic macular oedema: a systematic review with meta-analysis of real-world experience

We conducted a meta-analysis of real-world studies on the 0.19 mg Fluocinolone Acetonide (FAc) intravitreal implant for chronic diabetic macular oedema (DMO), comparing these findings with the Fluocinolone Acetonide for Diabetic Macular Edema (FAME) study. The primary outcome was mean change of best corrected visual acuity (BCVA) at 24 months. Secondary outcomes were 36-month mean BCVA, mean central macular thickness (CMT) change, rates of eyes receiving supplementary intravitreal therapy, cataract surgery, intraocular pressure (IOP)-lowering drops and glaucoma surgery. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated. Nine real-world studies were included. The FAc implant yielded a significantly improved BCVA at 24 and 36 months (24-month MD = 4.52; 95% CI 2.56–6.48; 36-month MD = 8.10; 95% CI 6.34–9.86). These findings were comparable with the FAME study. The FAc implant yielded significantly reduced 24- and 36-month CMT. Pooled proportions of cataract surgery, IOP-lowering drops and glaucoma surgery were 39%, 27% and 3%, respectively, all lower than the FAME study. Pooled estimate of supplementary intravitreal therapy was 39%, higher than the 15.2% of the FAME study. This meta-analysis of real-world studies confirms favorable visual and anatomical outcomes following FAc insert for chronic DMO. In real-life studies more than one third of patients received supplementary intravitreal therapy, an issue that needs to be further explored.

Intravitreal bevacizumab versus intravitreal triamcinolone for diabetic macular edema-Systematic review, meta-analysis and meta-regression

BACKGROUND

The most frequent cause of vision loss from diabetic retinopathy is diabetic macular edema (DME). Earlier clinical trials tried to examine the role of intravitreal triamcinolone (IVT) and intravitreal bevacizumab (IVB) in DME; they either qualified IVT over IVB or IVB over IVT or did not exhibit a significant difference.

OBJECTIVE

This paper aims to compare the efficacy and safety of IVB versus IVT alone or combined IVB+IVT in the treatment of DME.

METHODS

We systematically searched PubMed, CENTRAL, Scopus, Embase, Science Direct, OVID, and Web of Science for randomized controlled trials of IVB versus IVT alone or combined IVB+IVT and IVT versus the combined IVB+IVT in DME patients.

RESULTS

A total of 1243 eyes of 17 trials were included in our meta-analysis and regression. Repeated injections of IVB were superior at improving VA comparing with those of IVT at 12, 24, 48-weeks, and IVB+IVT at 12, 24, 48-weeks. Single injections were comparable across the three arms regarding BCVA improvement. CMT reductions were also comparable across the three arms. Meanwhile, the overall safety regarding intraocular pressure and intraocular hypertension significantly favored the IVB group. Improvement in VA was best modified with CMT reduction from 480 um to 320um. This association was significant at 12-weeks in the three arms and persisted till 24-weeks and 48-weeks exclusively in the IVB group.

CONCLUSIONS AND RELEVANCE

Our analysis reveals that repeated successive injections associate with better BCVA compared to single injection. Current evidence affirms that IVB is superior to IVT and IVB+IVT at improving BCVA, comparable at reducing CMT, and presents a better safety profile in the treatment of DME.

Dexamethasone delivery to the ocular posterior segment by sustained-release Laponite formulation

This paper presents a novel nanoformulation for sustained-release delivery of dexamethasone (DEX) to the ocular posterior segment using a Laponite (LAP) carrier-DEX/LAP 1:10 w w^-1 formulation; 10 mg ml^-1. In vivo ocular feasibility and pharmacokinetics after intravitreal (IV) and suprachoroidal (SC) administration in rabbit eyes are compared against IV administration of a DEX solution (1 mg ml^-1). Thirty rabbit eyes were injected with the DEX/LAP formulation (15 suprachoroid/15 intravitreous). Ophthalmological signs were monitored at day 1 and at weeks 1-4-12-24 post-administration. Three eyes per sample time point were used to quantify DEX concentration using high-performance liquid chromatography-mass spectrometry. The ocular tissues' pharmacokinetic parameters (lens, vitreous humour, choroid-retina unit and sclera) were studied. DEX/LAP was well tolerated under both administration methods. Peak intraocular DEX levels from the DEX/LAP were detected in the vitreous humour after both deliveries soon after administration. The vitreous area under the curve was significantly greater after both DEX/LAP deliveries (IV: 205 968.47; SC: 11 442.22 ng g^-1 d^-1) than after IV administration of the DEX solution (317.17 ng g^-1 d^-1). Intravitreal DEX/LAP delivery extended higher vitreous DEX levels up to week 24 (466.32 ± 311.15 ng g^-1). With SC delivery, DEX levels were detectable in the choroid-retina unit (12.04 ± 20.85 ng g^-1) and sclera (25.46 ± 44.09 ng g^-1) up to week 24. This study demonstrated the intraocular feasibility of both SC and IV administration of the DEX/LAP formulation. The LAP increased the intraocular retention time of DEX when compared with conventional solutions. DEX/LAP could be considered a biocompatible and useful sustained-release formulation for treating posterior-pole eye diseases.

Steroid-induced glaucoma: Epidemiology, pathophysiology, and clinical management

Glucocorticoids are a class of anti-inflammatory drugs commonly used to treat various ocular and systemic conditions. Although the role of glucocorticoids in the treatment of numerous serious inflammatory diseases is pivotal, their prolonged use may increase intraocular pressure resulting in steroid-induced glaucoma. We provide a detailed update on steroid-induced glaucoma as a preventable cause of blindness in the adult and pediatric population and describe its epidemiology, social impact, and risk factors. Furthermore, we explore the propensity of different steroids to increase the intraocular pressure, the role of different routes of steroid administration, dosage and duration of treatment, as well as the clinical features, genetics, and management of steroid-induced glaucoma.

Effect of Baseline Subretinal Fluid on Treatment Outcomes in VIVID-DME and VISTA-DME Studies

PURPOSE

To evaluate the effect of baseline subretinal fluid (SRF) on treatment outcomes with intravitreal aflibercept injection (IAI) versus laser treatment in patients with diabetic macular edema (DME) in the VIVID and VISTA studies.

DESIGN

Post hoc analysis of 2 randomized controlled trials.

PARTICIPANTS

Eight hundred seventy-two patients with DME.

METHODS

We randomized patients to receive IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser.

MAIN OUTCOME MEASURES

Effect of presence or absence of baseline SRF on visual outcomes in the integrated dataset at weeks 52 and 100.

RESULTS

Mean best-corrected visual acuity (BCVA) gains in the 2q4, 2q8, and laser arms at week 52 were +14.5, +11.0, and -2.3 letters, respectively, (those with baseline SRF) and +10.3, +10.6, and +2.5 letters, respectively, (those without). At week 100, mean gains were +13.5, +10.9, and -2.3 letters (those with baseline SRF) and +10.6, +10.0, and +2.7 letters (those without). The treatment effect for IAI versus laser from baseline to week 52 of 100 was greater for patients with baseline SRF versus those without (nominal P < 0.001, for interaction). The proportions of patients who gained 15 letters or more in the 2q4, 2q8, and laser arms at week 52 were 52.3%, 40.2%, and 8.9%, respectively, (those with baseline SRF) and 30.9%, 29.1%, and 8.2%, respectively, (those without) and at week 100 were 50.0%, 35.4%, and 12.9%, respectively, (those with baseline SRF) and 33.3%, 30.5%, and 12.5%, respectively, (those without). Time to first sustained SRF clearance seemed to be shorter in the IAI arms versus laser. The overall safety profile was similar in the IAI arms.

CONCLUSIONS

This post hoc analysis demonstrated the visual outcome benefits of IAI over laser, regardless of baseline SRF status. A greater treatment effect of IAI was observed in patients with baseline SRF versus those without; however, no meaningful impact of baseline SRF status on treatment outcomes with IAI was demonstrated, indicating that the differential effects of laser might have been the driving force behind the different treatment outcomes in both groups.

Real-World Assessment of Dexamethasone Intravitreal Implant in DME: Findings of the Prospective, Multicenter REINFORCE Study

BACKGROUND AND OBJECTIVE

Dexamethasone intravitreal implant (DEX) (Ozurdex; Allergan plc, Dublin, Ireland) is approved for the treatment of diabetic macular edema (DME). This study assessed the real-world effectiveness, safety, and reinjection interval of DEX in adult patients with DME.

PATIENTS AND METHODS

This was a phase 4, prospective, multicenter (18 U.S. sites), observational study.

RESULTS

The study population comprised 177 patients (180 eyes; 93.8% previously treated). Baseline mean best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were 54.4 letters and 424.6 μm, respectively. DEX was administered as monotherapy or with other DME therapy (55%/45%). The mean reinjection interval was 5.0 months. Mean maximum BCVA change from baseline after the first three DEX injections was +9.1 letters, +7.7 letters, and +7.0 letters, respectively (P < .001); 36.0% of eyes achieved 15-letter or greater BCVA improvement. Mean maximum CRT change from baseline was -137.7 μm (P < .001).

CONCLUSION

DEX used alone or with other DME therapy improved visual and anatomic outcomes in DME patients in clinical practice, with no new safety concerns. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:425-435.].

Long-term efficacy and safety profile of multiple injections of intravitreal dexamethasone implant to manage diabetic macular edema: A systematic review of real-world studies

INTRODUCTION

Systematic review of real-world studies about repeated dexamethasone intravitreal implant (DEXi) 0.7 mg in diabetic macular edema management, in order to identify the effective window of time occurring between injections, the critical evaluation of efficacy of the treatment, and the relative long-term safety in the real life setting.

METHODS

Literature databases such as PubMed, SCOPUS, and EMBASE were used to identify reports including DEX implant injections.

RESULTS

Twenty-one peer-reviewed publications were identified. DEX implants retreatment was considered on a pro re nata (PRN) basis at any time or starting from month three or four. About 1/3 of the eyes were retreated before six months from first injection (range 0-86.7%). Mean retreatment average time was 5.3 ± 0.9 months, with an estimated average of 1.3 injections each six months. There was no statistical correlation between average retreatment time and incidence of adverse events or other variables investigated. Limited safety issues related to implants number have been found, suggesting an overall good tolerance of long-term DEXi.

CONCLUSIONS

Comprehensive evaluation of real-world data suggests an average DEXi duration close to five months, following a PRN treatment strategy, including about 1/3 of patients. Repeated DEXi administration revealed an acceptable long-term efficacy/safety ratio.

Effectiveness and Safety of Intravitreal Dexamethasone Implant (Ozurdex) in Patients with Diabetic Macular Edema: A Real-World Experience

INTRODUCTION

There are few real-life studies on the intravitreal 0.7-mg dexamethasone implant for the treatment of diabetic macular edema (DME) conducted in Latin America. We aimed to assess the effectiveness and safety of this implant in clinical practice.

METHODS

Twenty-seven centers from Brazil and one from Argentina provided information on patients with DME treated with Ozurdex. The efficacy outcome variables were best-corrected visual acuity (BCVA) in Snellen and central retinal thickness (CRT). Safety was assessed by the elevation in intraocular pressure (IOP), occurrence of cataracts, and adverse events.

RESULTS

A total of 329 eyes (both treated cases and naïve eyes) from 282 patients underwent treatment. The time since diagnosis of DME ranged from 1 to 156 months. The median BCVA was 0.7 logMAR/50 letters at baseline and 0.3 logMAR/70 letters after treatment (both p < 0.001). Median CRT values decreased from 425 µm at baseline to 270 µm after treatment (p < 0.001). Increases in IOP of at least 10 mm Hg were observed in 7.4% of eyes, and 4% of eyes had cataract evolution. No cases of endophthalmitis were reported.

CONCLUSION

These real-life results suggest that the intravitreal dexamethasone implant is effective and safe for eyes with DME.

Protective effects of a novel drug RC28-E blocking both VEGF and FGF2 on early diabetic rat retina

AIM

To investigate protective effects of a novel recombinant decoy receptor drug RC28-E on retinal damage in early diabetic rats.

METHODS

The streptozotocin (STZ)-induced diabetic rats were randomly divided into 6 groups: diabetes mellitus (DM) group (saline, 3 µL/eye); RC28-E at low (0.33 µg/µL, 3 µL), medium (1 µg/µL, 3 µL), and high (3 µg/µL, 3 µL) dose groups; vascular endothelial growth factor (VEGF) Trap group (1 µg/µL, 3 µL); fibroblast growth factor (FGF) Trap group (1 µg/µL, 3 µL). Normal control group was included. At week 1 and 4 following diabetic induction, the rats were intravitreally injected with the corresponding solutions. At week 6 following the induction, apoptosis in retinal vessels was detected by TUNEL staining. Glial fibrillary acidic protein (GFAP) expression was examined by immunofluorescence. Blood-retinal barrier (BRB) breakdown was assessed by Evans blue assay. Ultrastructural changes in choroidal and retinal vessels were analyzed by transmission electron microscopy (TEM). Content of VEGF and FGF proteins in retina was measured by enzyme linked immunosorbent assay (ELISA). The retinal expression of intercellular cell adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), VEGF and FGF genes was examined by quantitative polymerase chain reaction (qPCR).

RESULTS

TUNEL staining showed that the aberrantly increased apoptotic cells death in diabetic retinal vascular network was significantly reduced by treatments of medium and high dose RC28-E, VEGF Trap, and FGF Trap (all P<0.05), the effects of medium and high dose RC28-E or FGF Trap were greater than VEGF Trap (P<0.01). GFAP staining suggested that reactive gliosis was substantially inhibited in all RC28-E and VEGF Trap groups, but the inhibition in FGF Trap group was not as prominent. Evans blue assay demonstrated that only high dose RC28-E could significantly reduce vascular leakage in early diabetic retina (P<0.01). TEM revealed that the ultrastructures in choroidal and retinal vessels were damaged in early diabetic retina, which was ameliorated to differential extents by each drug. The expression of VEGF and FGF2 proteins was significantly upregulated in early diabetic retina, and normalized by RC28-E at all dosages and by the corresponding Traps. The upregulation of ICAM-1 and TNF-α in diabetic retina was substantially suppressed by RC28-E and positive control drugs.

CONCLUSION

Dual blockade of VEGF and FGF2 by RC28-E generates remarkable protective effects, including anti-apoptosis, anti-gliosis, anti-leakage, and improving ultrastructures and proinflammatory microenvironment, in early diabetic retina, thereby supporting further development of RC28-E into a novel and effective drug to diabetic retinopathy (DR).

Evaluation of contrast sensitivity and other visual function outcomes in diabetic macular edema patients following treatment switch to aflibercept from ranibizumab

Purpose

This study aims to investigate changes in contrast sensitivity (CS), visual acuity (VA), central retinal thickness (CRT), and vision-related quality of life in subjects with recalcitrant diabetic macular edema switched from long-term ranibizumab treatment to aflibercept.

Patients and methods

In this prospective, investigator-masked, single-center study, 40 patients with persistent fluid, despite previous ranibizumab treatment, were switched to aflibercept with 5 consecutive monthly doses. The primary outcome was mean change from baseline to week 20 in Pelli–Robson CS. Secondary outcomes were mean change from baseline in best-corrected VA (BCVA), CRT, and National Eye Institute 25-Item Visual Function Questionnaire score.

Results

Fifty eyes (baseline VA >6/30) were evaluated. A median of 21.1±11.9 (range 5–55) ranibizumab injections were administered prior to initiation of aflibercept. Mean CS improved from 1.40±0.14 log units at baseline to 1.46±0.15 log units at week 20 (P<0.001). VA improved with mean logarithm of the minimum angle of resolution BCVA of 0.33±0.19 at baseline compared with logarithm of the minimum angle of resolution BCVA of 0.28±0.16 at week 20 (P=0.0016). Mean CRT decreased from 324±85 to 289±61 µm (P<0.001). Twenty-two (55%) patients experienced an overall improvement in National Eye Institute 25-Item Visual Function Questionnaire score. Interestingly, an association was found between changes in CS and change in CRT (r²=0.385, P<0.001) and between changes in BCVA and change in CRT (r²=0.092, P=0.032).

Conclusion

Switching from ranibizumab to aflibercept in patients with recalcitrant diabetic macular edema resulted in an improvement in all measured metrics, including CS, VA, and CRT. A majority of patients also indicated an improvement in vision-related quality of life. The finding of a stronger relationship between changes in CRT and CS compared with changes in CRT and BCVA suggests that the inclusion of CS as an endpoint may yield a more complete understanding of visual outcomes than that obtained by using VA alone.

Aflibercept in the Treatment of Diabetic Macular Edema: A Review and Consensus Paper

Purpose

To reach a consensus, among experts, on the role of aflibercept in diabetic macular edema (DME) through literature review.

Methods

Two round tables, involving 12 Italian experts, were organized: in the first one, 6 pharmacologic and clinical questions were selected and analyzed by a systematic literature review, using a population, intervention, control, and outcomes framework; in the second one, the nominal group technique was used to discuss relevant evidence related to each question. The consensus was assessed using the 5-point Delphi score.

Results

Agreement on statements was reached on 6/6 questions. The final statements were as follows: 1) High levels of both vascular endothelial growth factor (VEGF) and placental growth factor play an important role in the pathogenesis of DME. 2) The aflibercept pharmacologic profile is notably different from that of other anti-VEGF. 3) Aflibercept significantly improves functional and anatomical outcomes, and rapidly improves best-corrected visual acuity up to its peak; these results remain stable over time. 4) Diabetic macular edema aflibercept treatment requires a 5-monthly injection loading phase. Alternatively, a personalized pro re nata (PRN) regimen based on monthly monitoring and strict retreatment criteria can be used. 5) As an alternative to the bimonthly fixed regimen, in the maintenance phase the treatment schedule may be a PRN regimen with strict retreatment criteria or a treat and extend regimen. 6) No concerns on aflibercept ocular and systemic safety emerged from the literature.

Conclusions

Consensus was reached among experts on how to best treat patients with DME with aflibercept.

Corticosteroid Treatment in Diabetic Macular Edema

Diabetic macular edema is the most common cause of visual impairment in patients with diabetes mellitus. The pathogenesis of macular edema is complex and multifactorial. For many years, laser photocoagulation has been considered the standard therapy for the treatment of diabetic macular edema; however, few patients achieve significant improvements in visual acuity. Today the intravitreal administration of anti-inflammatory or anti-angiogenic agents together with the use of laser photocoagulation represents the standard of care for the treatment of this complication. The intravitreal route of administration minimizes the systemic side effects of corticosteroids. Steroid-related ocular side effects are elevated intraocular pressure and cataract, while injection-related complications include endophthalmitis, vitreous hemorrhage, and retinal detachment. In order to reduce the risks and complications, intravitreal implants have been developed recently to provide sustained release of corticosteroids and reduce repeated injections for the management of diabetic macular edema. In this review, the efficacy, safety, and therapeutic potential of intravitreal corticosteroids in diabetic macular edema are discussed with a review of recent literature.

Dietary Compound Chrysin Inhibits Retinal Neovascularization with Abnormal Capillaries in db/db Mice

Diabetic retinopathy (DR) develops in a significant proportion of patients with chronic diabetes, characterized by retinal macular edema and abnormal retinal vessel outgrowth leading to vision loss. Chrysin, a naturally-occurring flavonoid found in herb and honeycomb, has anti-inflammatory, antioxidant, and anti-cancer properties. This study sought to determine the protective effects of chrysin on retinal neovascularization with abnormal vessels and blood-retinal barrier (BRB) breakdown in 33 mM glucose-exposed human retinal endothelial cells and in db/db mouse eyes. High glucose caused retinal endothelial apoptotic injury, which was inhibited by submicromolar chrysin. This compound diminished the enhanced induction of HIF-1α, vascular endothelial growth factor (VEGF), and VEGF receptor-2 (VEGFR2) in high glucose-exposed retinal endothelial cells. Consistently, oral administration of 10 mg/kg chrysin reduced the induction of these proteins in db/db mouse eye tissues. In addition, chrysin restored the decrement of VE-cadherin and ZO-1 junction proteins and PECAM-1 in hyperglycemia-stimulated retinal endothelial cells and diabetic mouse retina, possibly maintaining tight cell-cell interactions of endothelial cells and pericytes. Anti-apoptotic chrysin reduced the up-regulation of Ang-1, Ang-2, and Tie-2 crucial to retinal capillary occlusion and BRB permeability. Furthermore, orally treating chrysin inhibited acellular capillary formation, neovascularization, and vascular leakage observed in diabetic retinas. These observations demonstrate, for the first time, that chrysin had a capability to encumber diabetes-associated retinal neovascularization with microvascular abnormalities and BRB breakdown.

Corticosteroids and the retina: a role for the mineralocorticoid receptor

PURPOSE OF REVIEW

Long-lasting devices releasing steroids have been approved recently for macular edema of various origins. Identification of the retina as a novel mineralo-sensitive tissue also raises new therapeutic options.

RECENT FINDINGS

Recently, the over activation of the mineralocorticoid receptor (MR) pathway has been shown to cause fluid accumulation in the retina, choroidal vasodilation, and to promote retinal neovascularization in hypoxic conditions. These findings indicate that MR antagonists could have beneficial effects in the treatment of retinal diseases. Central serous chorioretinopathy is a retinal disease associated with choroidal vasodilation and subretinal fluid that affects mostly men with type A personality and occurrence has been associated with steroid intake. In several independent studies, MR antagonists have shown beneficial effects, significantly reducing subretinal fluid in eyes of chronic central serous chorioretinopathy patients.

SUMMARY

The role of MR in retinal disorder is emerging and the potential association with psychological traits is considered. The place of MR antagonists for retinal diseases treatment is discussed.

Intravitreal Aflibercept for Diabetic Macular Edema: 148-Week Results from the VISTA and VIVID Studies

PURPOSE

To compare efficacy and safety of intravitreal aflibercept injection (IAI) with macular laser photocoagulation for diabetic macular edema (DME) over 3 years.

DESIGN

Two similarly designed phase 3 trials: VISTA^DME and VIVID^DME.

PARTICIPANTS

Patients (eyes; n = 872) with central-involved DME.

METHODS

Eyes received IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser control. From week 24, if rescue treatment criteria were met, IAI patients received active laser, and laser control patients received IAI 2q8. From week 100, laser control patients who had not received IAI rescue treatment received IAI as needed per retreatment criteria.

MAIN OUTCOME MEASURES

The primary end point was the change from baseline in best-corrected visual acuity (BCVA) at week 52. We report the 148-week results.

RESULTS

Mean BCVA gain from baseline to week 148 with IAI 2q4, IAI 2q8, and laser control was 10.4, 10.5, and 1.4 letters (P < 0.0001) in VISTA and 10.3, 11.7, and 1.6 letters (P < 0.0001) in VIVID, respectively. The proportion of eyes that gained ≥15 letters from baseline at week 148 was 42.9%, 35.8%, and 13.6% (P < 0.0001) in VISTA and 41.2%, 42.2%, and 18.9% (P < 0.0001) in VIVID, respectively. Greater proportions of eyes treated with IAI 2q4 and IAI 2q8 versus those treated with laser control had an improvement of ≥2 steps in the Diabetic Retinopathy Severity Scale (DRSS) score in both VISTA (29.9% and 34.4% vs. 20.1% [P = 0.0350, IAI 2q4; P = 0.0052, IAI 2q8]) and VIVID (44.3% and 47.8% vs. 17.4% [P < 0.0001 for both]). In an integrated safety analysis, the most frequent ocular serious adverse event was cataract (3.1%, 2.1%, 0.3% for 2q4, 2q8, and control).

CONCLUSIONS

Visual improvements observed with both IAI regimens (over laser control) at weeks 52 and 100 were maintained at week 148, with similar overall efficacy in the IAI 2q4 and IAI 2q8 groups. Treatment with IAI also had positive effects on the DRSS score. Over 148 weeks, the incidence of adverse events was consistent with the known safety profile of IAI.

Controlled Release of Dexamethasone From an Intravitreal Delivery System Using Porous Silicon Dioxide

PURPOSE

The current study aims to evaluate a porous silicon-based drug delivery system meant for sustained delivery of dexamethasone (Dex) to the vitreous and retina.

METHODS

Dexamethasone was grafted covalently into the pore walls of fully oxidized porous silicon particles (pSiO2-COO-Dex), which then was evaluated for the pharmacological effect of the payload on cultured ARPE19 cells before intravitreal injection. The Dex release profile was investigated in a custom designed dynamic dissolution chamber to mimic the turnover of vitreous fluid in rabbit eyes. Ocular safety, in vivo release, and pharmacodynamics were evaluated in rabbit eyes, and the human VEGF-induced rabbit retinal vascular permeability model.

RESULTS

Loading efficiency of Dex was 69 ± 9 μg per 1 mg of the pSiO2-COO-Dex particles. Dynamic in vitro release demonstrated a sustained mode when compared to free Dex, with the drug half-life extended by 5 times. The released Dex was unaltered and biologically active. In vivo drug release in rabbit eyes revealed a mode similar to the release seen in vitro, with a vitreous half-life of 11 days. At 2 and 4 weeks after a single intravitreal injection of pSiO2-COO-Dex particles (mean 2.71 ± 0.47 mg), intravitreal 500 ng of VEGF did not induce significant retinal vessel dilation or fluorescein leakage, while these events were observed in the eyes injected with empty pSiO2 particles or with free Dex. The retinal vessel score from fluorescein angiography for the control eyes was double the score for the eyes injected with pSiO2-COO-Dex. No adverse reaction was observed for the eyes injected with drug-loaded pSi particles during the course of the study.

CONCLUSIONS

The porous silicon-based Dex delivery system (pSiO2-COO-Dex) can be administered safely into vitreous without toxicity. Dex release from the porous silicon particles was sustained for 2 months and was effective against VEGF-induced retinal vessel reaction.

Minimally Invasive Microincision Vitrectomy Surgery with an Intraoperative Dexamethasone Implant for Refractory Diabetic Macular Edema

PURPOSE

To evaluate the 1-year results of 25-gauge microincision vitrectomy surgery (MIVS25) combined with intraoperative dexamethasone (DEX) implant for persistent diabetic macular edema (DME).

METHODS

This study enrolled patients who had a history of DME for ≥12 months and underwent MIVS25 and DEX implant injection. Best corrected visual acuity (BCVA) and central retinal thickness (CRT) were assessed postoperatively.

RESULTS

Eighteen eyes were included in the analysis. Preoperatively, logMAR BCVA was 0.90 and CRT was 594 µm on average. CRT decreased until the 3-month follow-up visit and tended to increase at 6 months, but stabilized at 12 months with additional treatments in five eyes at 5 months postoperatively. Statistically significant improvement in BCVA was noted 1 month after treatment and at each subsequent follow-up visit (p < 0.001).

CONCLUSION

MIVS25 combined with DEX implant injection might be utilized as an effective and safe alternative treatment for intractable DME.

Topical dexamethasone γ-cyclodextrin nanoparticle eye drops increase visual acuity and decrease macular thickness in diabetic macular oedema

PURPOSE

To compare in a randomized, controlled trial topical 1.5% dexamethasone γ-cyclodextrin nanoparticle eye drops (DexNP) with posterior subtenon injection of triamcinolone acetonide in diabetic macular oedema (DME).

METHODS

In this prospective, randomized, controlled trial, 22 eyes of 22 consecutive patients with DME were randomized to (i) topical treatment with DexNP ×3/day (4 weeks), ×2/day (4 weeks) and ×1/day (4 weeks) or (ii) one posterior subtenon injection of 20 mg triamcinolone acetonide. Study visits were at baseline and 4, 8, 12 and 16 weeks.

RESULTS

The logMAR (Snellen) visual acuity (mean ± SD) improved significantly with DexNP from 0.41 ± 0.3 (Snellen 0.39) to 0.32 ± 0.25 (0.48) and 0.30 ± 0.26 (0.50) at 4 and 8 weeks, respectively. One-third of the DexNP group improved more than 0.3 logMAR units. For triamcinolone, logMAR changed significantly from 0.42 ± 0.28 (0.38) at baseline to 0.32 ± 0.29 (0.48) at 4w and 0.33 ± 0.37 (0.47) at 12w. The central macular thickness (CMT) decreased significantly with DexNP from 483 ± 141 μm to 384 ± 142 μm at 4w and 342 ± 114 μm at 8w. For triamcinolone, CMT decreased significantly at all time-points: 494 ± 94 μm, 388 ± 120, 388 ± 145, 390 ± 136 and 411 ± 104 μm at 0, 4, 8, 12 and 16 weeks, respectively. There was a modest increase in intraocular pressure (IOP) at all time-points with DexNP while no increase was seen with triamcinolone. Serum cortisol was affected by both treatments.

CONCLUSION

Topical DexNP significantly improve visual acuity and decrease macular thickness in patients with DME. The effect is similar to that from subtenon triamcinolone. A modest increase in IOP was seen with the nanoparticle eye drops, but IOP normalized after the discontinuation of treatment.

Sustained-release steroids for the treatment of diabetic macular edema

Glucocorticoids have been used for decades in the treatment of ocular disorders via topical, periocular, and more recently intravitreal routes. However, their exact mechanisms of action on ocular tissues remain imperfectly understood. Fortunately, two recently approved intravitreal sustained-release drug delivery systems have opened new perspectives for these very potent drugs. To date, among other retinal conditions, their label includes diabetic macular edema, for which a long-lasting therapeutic effect has been demonstrated both morphologically and functionally in several randomized clinical trials. The rate of ocular complications of intravitreal sustained-release steroids, mainly cataract formation and intraocular pressure elevation, is higher than with anti-vascular endothelial growth factor agents. Yet, a better understanding of the mechanisms underlying these adverse effects and the search for the minimal efficient dose should help optimize their therapeutic window.

The Vitreomacular Interface in Diabetic Retinopathy

Diabetic retinopathy (DR) is a leading health concern and a major cause of blindness. DR can be complicated by scar tissue formation, macular edema, and tractional retinal detachment. Optical coherence tomography has found that patients with DR often have diffuse retinal thickening, cystoid macular edema, posterior hyaloid traction, and tractional retinal detachment. Newer imaging techniques can even detect fine tangential folds and serous macular detachment. The interplay of the vitreous and the retina in the progression of DR involves multiple chemokine and other regulatory factors including VEGF. Understanding the cells infiltrating pathologic membranes at the vitreomacular interface has opened up the possibility of new targets for pharmacotherapy. Vitrectomies for DR remain a vital tool to help relieve tension on the macula by removing membranes, improving edema absorption, and eliminating the scaffold for new membrane formation. Newer treatments such as triamcinolone acetonide and VEGF inhibitors have become essential as a rapid way to control DR at the vitreomacular interface, improve macular edema, and reduce retinal neovascularization. These treatments alone, and in conjunction with PRP, help to prevent worsening of the VMI in patients with DR.

Intravitreal Aflibercept for Diabetic Macular Edema: 100-Week Results From the VISTA and VIVID Studies

PURPOSE

To compare efficacy and safety of 2 dosing regimens of intravitreal aflibercept injection (IAI) with macular laser photocoagulation for diabetic macular edema (DME).

DESIGN

Two similarly designed, randomized, phase 3 trials, VISTA(DME) and VIVID(DME).

PARTICIPANTS

Patients (eyes; n=872) with type 1 or 2 diabetes mellitus who had DME with central involvement.

METHODS

Eyes received IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 8 weeks after 5 monthly doses (2q8), or laser control.

MAIN OUTCOME MEASURES

The primary end point was mean change from baseline in best-corrected visual acuity (BCVA) at week 52. This report presents the 100-week results including mean change from baseline in BCVA, proportion of eyes that gained ≥15 letters, and proportion of eyes with a ≥2-step improvement in the Diabetic Retinopathy Severity Scale (DRSS) score.

RESULTS

Mean BCVA gain from baseline to week 100 with IAI 2q4, IAI 2q8, and laser control was 11.5, 11.1, and 0.9 letters (P < 0.0001) in VISTA and 11.4, 9.4, and 0.7 letters (P < 0.0001) in VIVID, respectively. The proportion of eyes that gained ≥15 letters from baseline at week 100 was 38.3%, 33.1%, and 13.0% (P < 0.0001) in VISTA and 38.2%, 31.1%, and 12.1% (P ≤ 0.0001) in VIVID. The proportion of eyes that lost ≥15 letters at week 100 was 3.2%, 0.7%, and 9.7% (P ≤ 0.0220) in VISTA and 2.2%, 1.5%, and 12.9% (P ≤ 0.0008) in VIVID. Significantly more eyes in the IAI 2q4 and 2q8 groups versus those in the laser control group had a ≥2 step improvement in the DRSS score in both VISTA (37.0% and 37.1% vs. 15.6%; P < 0.0001) and VIVID (29.3% and 32.6% vs. 8.2%; P ≤ 0.0004). In an integrated safety analysis, the most frequent serious ocular adverse event was cataract (2.4%, 1.0%, and 0.3% for 2q4, 2q8, and control).

CONCLUSIONS

In both VISTA and VIVID, the 52-week visual and anatomic superiority of IAI over laser control was sustained through week 100, with similar efficacy in the 2q4 and 2q8 groups. Safety in these studies was consistent with the known safety profile of IAI.

Systematic review and mixed treatment comparison of intravitreal aflibercept with other therapies for diabetic macular edema (DME)

Background

This was an indirect comparison of the effectiveness of intravitreal aflibercept (IVT-AFL) 2 mg every 8 weeks after 5 initial monthly doses (or if different periods, after an initial monthly dosing period) (2q8) and other diabetic macular edema (DME) therapies at doses licensed outside the USA.

Methods

A comprehensive search was undertaken to source relevant studies. Feasibility networks were prepared to identify viable comparisons of 12-month outcomes between IVT-AFL 2q8 and therapies licensed outside the USA, which were assessed for clinical and statistical homogeneity. Pooled effect sizes (mean difference [MD] and relative risk/risk ratio [RR]) were calculated using fixed- and random-effects models. Indirect comparisons were performed using Bucher analysis. If at least one ‘head-to-head’ study was found then a mixed treatment comparison (MTC) was performed using Bayesian methods. Two 12-month comparisons could be undertaken based on indirect analyses: IVT-AFL 2q8 versus intravitreal ranibizumab (IVR) 0.5 mg as needed (PRN) (10 studies) and IVT-AFL 2q8 versus dexamethasone 0.7 mg implants (three studies).

Results

There was an increase in mean best-corrected visual acuity (BCVA) with IVT-AFL 2q8 over IVR 0.5 mg PRN by 4.67 letters [95% credible interval (CrI): 2.45–6.87] in the fixed-effect MTC model (10 studies) and by 4.82 letters [95% confidence interval (CI): 2.52–7.11] in the Bucher indirect analysis (four studies). IVT-AFL 2q8 doubled the proportion of patients gaining ≥ 10 Early Treatment Diabetic Retinopathy Study letters at 12 months compared with dexamethasone 0.7 mg implants (RR = 2.10 [95% CI: 1.29–3.40]) in the fixed-effect model. There were no significant differences in safety outcomes between IVT-AFL 2q8 and IVR 0.5 mg PRN or dexamethasone 0.7 mg implants.

Conclusions

Studies of IVT-AFL 2q8 showed improved 12-month visual acuity measures compared with studies of IVR 0.5 mg PRN and dexamethasone 0.7 mg implants based on indirect comparisons. These analyses are subject to a number of limitations which are inherent in indirect data comparisons.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-015-0035-x) contains supplementary material, which is available to authorized users.

Novel approaches for treating diabetic retinopathy based on recent pathogenic evidence

Diabetic retinopathy remains as a leading cause of blindness in developed countries. Current treatments target late stages of DR when vision has already been significantly affected. A better understanding of the pathogenesis of DR would permit the development of more efficient preventional/interventional strategies against early stages of DR. In this article a critical review of the state of the art of this issue is provided along with a discussion of problems which have yet to be overcome. Neuroprotection as a new approach for the treatment of the early stages of DR has been particularly emphasized. The development and progression of DR is not homogeneous and, apart from blood glucose levels and blood pressure, it depends on genetic factors which remain to be elucidated. In addition, the role of the pathogenic pathways is not the same in all patients. All these factors should be taken into account in the near future when an individualized oriented treatment for DR could become feasible. The new techniques in retinal imaging acquisition, the identification of useful circulating biomarkers and the individualized analysis of biological samples could facilitate the development of early and personalized therapy in the setting of DR. Finally, it should be noted that only a coordinated action among ophthalmologists, diabetologists, basic researchers, experts in pharmaco-economics and health care providers addressed to the design of rational strategies targeting prevention and the early stages of DR will be effective in reducing the burden and improving the clinical outcome of this devastating complication of diabetes.

Diabetic retinopathy - ocular complications of diabetes mellitus

In industrialized nations diabetic retinopathy is the most frequent microvascular complication of diabetes mellitus and the most common cause of blindness in the working-age population. In the next 15 years, the number of patients suffering from diabetes mellitus is expected to increase significantly. By the year 2030, about 440 million people in the age-group 20-79 years are estimated to be suffering from diabetes mellitus worldwide (prevalence 7.7%), while in 2010 there were 285 million people with diabetes mellitus (prevalence 6.4%). This accounts for an increase in patients with diabetes in industrialized nations by 20% and in developing countries by 69% until the year 2030. Due to the expected rise in diabetic patients, the need for ophthalmic care of patients (i.e., exams and treatments) will also increase and represents a challenge for eye-care providers. Development of optimized screening programs, which respect available resources of the ophthalmic infrastructure, will become even more important. Main reasons for loss of vision in patients with diabetes mellitus are diabetic macular edema and proliferative diabetic retinopathy. Incidence or progression of these potentially blinding complications can be greatly reduced by adequate control of blood glucose and blood pressure levels. Additionally, regular ophthalmic exams are mandatory for detecting ocular complications and initiating treatments such as laser photocoagulation in case of clinical significant diabetic macular edema or early proliferative diabetic retinopathy. In this way, the risk of blindness can considerably be reduced. In advanced stages of diabetic retinopathy, pars-plana vitrectomy is performed to treat vitreous hemorrhage and tractional retinal detachment. In recent years, the advent of intravitreal medication has improved therapeutic options for patients with advanced diabetic macular edema.

Dexamethasone Implants in Patients with Naïve or Refractory Diffuse Diabetic Macular Edema

PURPOSE

To assess the effect of dexamethasone (DEX) 0.7 mg (Ozurdex™) on refractory and treatment-naïve diffuse diabetic macular edema.

METHODS

A prospective study was conducted in 76 patients (40 refractory and 36 naïve) with visual acuities (VA) of 15-72 ETDRS letters, central macular thickness (CMT) >300 µm and intraocular pressure (IOP) <25 mm Hg. After the DEX implant (±photocoagulation), VA, CMT and total macular volume (TMV) were assessed monthly for 6 months.

RESULTS

At every visit, VA improved significantly from baseline (p < 0.001) in both groups, but values were significantly better in the naïve group, while CMT and TMV decreased significantly (p < 0.001) and similarly in both groups. The naïve group received more photocoagulations (p = 0.001). There were 7.9% transient IOP increases >10 mm Hg.

CONCLUSIONS

Substantial improvements in VA and CMT were achieved in both groups, and a gain of 1 ETDRS line was observed in the treatment-naïve group as compared to the refractory group, with a good safety profile in both.