Place of intravitreal dexamethasone implant in the treatment armamentarium of diabetic macular edema

Fenofibrate and diabetic retinopathy

Background

Diabetic retinopathy (DR), a sight-threatening ocular complication of diabetes mellitus, is one of the main causes of blindness in the working-age population. Dyslipidemia is a potential risk factor for the development or worsening of DR, with conflicting evidence in epidemiological studies. Fenofibrate, an antihyperlipidemic agent, has lipid-modifying and pleiotropic (non-lipid) effects that may lessen the incidence of microvascular events.

Methods

Relevant studies were identified through a PubMed/MEDLINE search spanning the last 20 years, using the broad term "diabetic retinopathy" and specific terms "fenofibrate" and "dyslipidemia". References cited in these studies were further examined to compile this mini-review. These pivotal investigations underwent meticulous scrutiny and synthesis, focusing on methodological approaches and clinical outcomes. Furthermore, we provided the main findings of the seminal studies in a table to enhance comprehension and comparison.

Results

Growing evidence indicates that fenofibrate treatment slows DR advancement owing to its possible protective effects on the blood-retinal barrier. The protective attributes of fenofibrate against DR progression and development can be broadly classified into two categories: lipid-modifying effects and non-lipid-related (pleiotropic) effects. The lipid-modifying effect is mediated through peroxisome proliferator-activated receptor-α activation, while the pleiotropic effects involve the reduction in serum levels of C-reactive protein, fibrinogen, and pro-inflammatory markers, and improvement in flow-mediated dilatation. In patients with DR, the lipid-modifying effects of fenofibrate primarily involve a reduction in lipoprotein-associated phospholipase A2 levels and the upregulation of apolipoprotein A1 levels. These changes contribute to the anti-inflammatory and anti-angiogenic effects of fenofibrate. Fenofibrate elicits a diverse array of pleiotropic effects, including anti-apoptotic, antioxidant, anti-inflammatory, and anti-angiogenic properties, along with the indirect consequences of these effects. Two randomized controlled trials-the Fenofibrate Intervention and Event Lowering in Diabetes and Action to Control Cardiovascular Risk in Diabetes studies-noted that fenofibrate treatment protected against DR progression, independent of serum lipid levels.

Conclusions

Fenofibrate, an oral antihyperlipidemic agent that is effective in decreasing DR progression, may reduce the number of patients who develop vision-threatening complications and require invasive treatment. Despite its proven protection against DR progression, fenofibrate treatment has not yet gained wide clinical acceptance in DR management. Ongoing and future clinical trials may clarify the role of fenofibrate treatment in DR management.

The Anatomic and Functional Outcomes of Ozurdex-Aided Vitrectomy in Proliferative Diabetic Retinopathy

Purpose

To investigate the 3-months outcomes of patients who underwent intraoperative intravitreal injection of Ozurdex for proliferative diabetic retinopathy (PDR).

Methods

This is a prospective randomized controlled clinical trial (ChiCTR2100043399). Seventy-one patients with PDR who had indications for surgery without intravitreal injection history within 3 months preoperatively were enrolled. Patients were randomly divided into three groups based on the medicine injected intraoperatively: Ozurdex, Conbercept, and Control group. The primary outcome is the best-corrected visual acuity (BCVA) within 3 months postoperatively. The secondary outcomes include the intraocular pressure (IOP), mean sensitivity, central retinal thickness and vessels perfusion.

Results

The BCVA and the mean sensitivity improved in the three groups (F = 130.8, P < 0.0001; F = 34.18, P < 0.0001), but there was no statistical difference among the three groups (F = 0.858, P = 0.552; F = 0.964, P = 0.452). The IOP was no significant differences among the three groups within 3 months postoperatively (F = 0.881, P = 0.533). Compared with the other two groups, central retinal thickness (CRT) and outer retinal layer (ORL) thickness decreased significantly in patients of the Ozurdex group (F = 3.037, P = 0.008; F = 2.626, P = 0.018), especially in the diabetic macular edema (DME) patients (F = 2.761, P = 0.0164; F = 2.572, P = 0.0240). In macular region, superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) perfusion were not shown statistical difference at 3 months postoperatively in the all three groups compared with 1 day postoperatively (P > 0.05).

Conclusion

Compared with the other two groups, anatomical outcomes was improved significantly in Ozurdex group for DR patients. Ozurdex may help to improve the visual acuity and visual sensitivity, and there is no significant difference in the change of IOP and microvascular improvement.

Clinical Trial Registration

This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn, registration number ChiCTR2100043399).

Intravitreal OZURDEX vs. Intravitreal Bevacizumab for Diabetic Macular Edema: A Comprehensive Review

This comprehensive review examines the efficacy, safety, and implications of intravitreal OZURDEX and intravitreal bevacizumab in treating diabetic macular edema (DME). DME is a common complication of diabetes mellitus and a leading cause of vision loss. OZURDEX, through sustained release of dexamethasone, targets inflammation and vascular permeability, while bevacizumab inhibits vascular endothelial growth factor (VEGF), reducing angiogenesis. However, differences in safety profiles exist, with OZURDEX associated with an increased risk of intraocular pressure elevation and cataract formation and bevacizumab potentially carrying systemic risks. The choice between these treatments should be individualized, considering patient preferences, ocular and systemic comorbidities, and cost-effectiveness. Collaboration among healthcare providers is essential for the comprehensive management of DME. Future research should focus on long-term comparative studies, predictors of treatment response, and exploration of novel therapeutic targets to optimize treatment outcomes for patients with DME.

Combined Therapy of Experimental Autoimmune Uveitis by a Dual-Drug Nanocomposite Formulation with Berberine and Dexamethasone

Purpose

Autoimmune uveitis is a kind of sight-threatening ocular and systemic disorders. Recent treatments on autoimmune uveitis still remain many limitations due to extreme complexity and undetermined pathogenesis. In this study, a novel dual-drug nanocomposite formulation is developed to treat experimental autoimmune uveitis by a combined and sustained therapy method.

Methods

The dual-drug nanocomposite formulation is constructed by integrating berberine (BBR)-loaded mesoporous silica nanoparticles (MSNs) into dexamethasone (DEX)-loaded thermogel (BBR@MSN-DEX@Gel). The BBR@MSN-DEX@Gel is characterized by transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectrometer and rheometer. The in vitro drug release profile, cytotoxicity and anti-inflammation effectiveness of BBR@MSN-DEX@Gel on lipopolysaccharide-stimulated human conjunctival epithelial cells are investigated. After the in vivo drug release profile and biosafety of the dual-drug nanocomposite formulation are confirmed, its treatment effectiveness is fully assessed based on the induced experimental autoimmune uveitis (EAU) Lewis rat's model.

Results

The dual-drug nanocomposite formulation has good injectability and thermosensitivity, suitable for administration by an intravitreal injection. The BBR@MSN-DEX@Gel has been found to sustainably release both drugs for up to 4 weeks. The carrier materials have minimal in vitro cytotoxicity and high in vivo biosafety. BBR@MSN-DEX@Gel presents obviously anti-inflammatory effectiveness in vitro. After administration of BBR@MSN-DEX@Gel into Lewis rat's eye with EAU by an intravitreal injection, the nanocomposite formulation significantly suppresses inflammatory reaction of autoimmune uveitis via a dual-drug combined and sustained therapy method, compared with the equivalent dose of single-component formulations.

Conclusion

BBR@MSN-DEX@Gel serves as a promising dual-drug nanocomposite formulation for future treatment of autoimmune uveitis.

Cost-Effectiveness of Dexamethasone Intravitreal Implant in Naïve and Previously Treated Patients with Diabetic Macular Edema

PURPOSE

To compare the direct costs associated with the dexamethasone intravitreal implant (DEX-i) in treatment-naïve and previously treated eyes with diabetic macular edema (DME) in a real clinical setting.

METHODS

Retrospective and single-center study conducted in a real clinical scenario. Consecutive DME patients, either naïve or previously treated with vascular endothelial growth factor inhibitors (anti-VEGF), who received treatment with one or more DEX-i between May 2015 and December 2020, and who were followed-up for a minimum of 12 months, were included in the study. The cost analysis was performed from the perspective of the Andalusian Regional Healthcare Service. The primary effectiveness endpoint was the probability of achieving an improvement in best-corrected visual acuity (BCVA) ≥ 15 ETDRS letters after 1 year of treatment. The incremental cost-effectiveness ratio (ICER) of different improvements in BCVA was calculated.

RESULTS

Forty-nine eyes, twenty-eight (57.1%) eyes from the treatment-naïve group and twenty-one (42.9%) from the previously treated group, were included in the analysis. The total cost of one year of treatment was significantly lower in the treatment-naïve eyes than in the previously treated eyes [Hodges-Lehmann median difference: EUR 819.1; 95% confidence interval (CI): EUR 786.9 to EUR 1572.8; p < 0.0001]. The probability of achieving a BCVA improvement of ≥15 letters at month 12 was significantly greater in the treatment-naïve group than in the previously treated group (rate difference: 0.321; 95% CI: 0.066 to 0.709; p = 0.0272). The Cochran-Mantel-Haenszel Odds Ratio of achieving a BCVA improvement of ≥15 letters at month 12 was 3.55 (95% CI: 1.09 to 11.58; p = 0.0309). In terms of ICER, the treatment-naïve group showed cost savings of EUR 7704.2 and EUR 5994.2 for achieving an improvement in BCVA ≥ 15 letters at month 12 and at any of the measured time points, respectively.

CONCLUSIONS

DEX-i was found to be more cost-effective in treatment-naïve eyes than in those previously treated with anti-VEGF. Further studies are needed to determine the most cost-effective treatment based on patient profile.

Morphological and functional changes in the macular area in diabetic macular edema after a single intravitreal injection of aflibercept

AIM

To evaluate the changes in macular morphology and function after a single intravitreal injection of aflibercept in diabetic macular edema (DME) using optical coherence tomography angiography (OCTA) and MP-3 microperimetry.

METHODS

Twenty-eight patients (42 eyes) diagnosed with DME were treated with intravitreal injection of aflibercept. The changes in best corrected visual acuity (BCVA), central retinal thickness (CRT), foveal avascular zone (FAZ) area, vessel density of superficial retinal capillary plexus (SVD), vessel density of deep retinal capillary plexus (DVD), mean light sensitivity (MLS), 2° fixation rate (P1), 4° fixation rate (P2), and other indicators 1mo after treatment were compared; of these, BCVA was converted into logarithm of the minimum angle of resolution (logMAR), and the correlation among the factors was analyzed.

RESULTS

After treatment, logMAR BCVA was 0.47±0.24, which was significantly better than that before treatment (0.63±0.28, P<0.001). The CRT was 359.21±107.87 µm after treatment, which was significantly lower than before treatment (474.10±138.20 µm, P<0.001). The FAZ area, SVD, and DVD were not significantly changed after treatment compared with the baseline. MLS was 22.16±4.20 dB after treatment, which was significantly higher than before treatment (19.63±4.23 dB, P<0.001). P2 significantly increased after treatment than before treatment (P=0.007). P1 had no significant change after treatment than before treatment (P=0.086).

CONCLUSION

A single intravitreal injection of aflibercept effectively reduces macular edema and improves retinal sensitivity, fixation stability, and visual acuity, possibly without causing significant changes in the retinal vascular condition in a short time.

Early-switch versus late-switch in patients with diabetic macular edema: a cost-effectiveness study

Background

To evaluate the cost-effectiveness of early- versus late-switch to the intravitreal-dexamethasone implant (DEX-i) in patients with diabetic macular edema (DME) who did not adequately respond to vascular endothelial growth factor inhibitors (anti-VEGF).

Methods

Retrospective analysis of a multicenter Clinical Data Registry. The registry included DME eyes who received 3 intravitreal anti-VEGF injections (early-switch) or > 3 intravitreal anti-VEGF injections (late-switch) before switching to DEX-i injections. The primary outcome was to estimate the incremental cost needed to obtain a best-corrected visual acuity (BCVA) improvement ≥ 0.1 or a central-retinal thickness CRT ≤ 250 μm.

Results

The analysis included 108 eyes, 32 (29.6%) and 76 (70.4%) in the early- and late-switch groups, respectively. Early-switch strategy was associated with a cost saving of €3,057.8; 95% CI: €2,406.4–3,928.4, p < 0.0001). Regarding incremental-cost-effectiveness ratio, late-switch group was associated with an incremental cost of €25,735.2 and €13,533.2 for achieving a BCVA improvement ≥ 0.1 at month 12 and at any of the time-point measured, respectively. At month 12, 38 (35.2%) eyes achieved a BCVA improvement ≥ 0.1. At month 12, 52 (48.1) eyes had achieved a CRT ≤ 250 micron. As compared to baseline, the mean (95% CI) CRT reduction was − 163.1 (− 212.5 to − 113.7) µm and − 161.6 (− 183.8 to − 139.3) µm in the early-switch and late-switch groups, respectively, p = 0.9463.

Conclusions

In DME eyes, who did not adequately respond to anti-VEGF, switching to DEX-i at early stages (after the first 3-monthly injections) was found to be more cost-effective than extending the treatment to 6-monthly injections of anti-VEGF.

Off-label uses of Aflibercept, Ranibizumab and Dexamethasone implant for diabetic retinopathy in Turkey

Objective: Diabetic retinopathy (DRP) is the most common retinal vascular disease leading to blindness. There is limited data about the off-label drug use for DRP and diabetic macular edema (DME) in literature. The aim of the article was to evaluate the applications for off-label drug use in patients with DME and DRP in Turkey in terms of demographic and clinical characteristics. Methods: Applications for off-label drug use from hospitals across Turkey to the Turkish Medicines and Medical Devices Agency for DRP in 2018 were reviewed retrospectively. Results: 112 approved applications for 167 eyes were included in our study. The mean age of the cases was 61.24 ± 10.23 years, of them 57.1% were males and 42.9% were females. Of these applications, 41.1% were for aflibercept (n:46), 33.9% for ranibizumab (n:38), and 25% for dexamethasone implant (n:28). There was no application for bevacizumab. In terms of referring hospitals, public university hospitals were in the first place with a rate of 70.5%. The most common reasons for applications were drug switchback request and failure to complete loading dose, respectively. Discussions: DRP treatment can sometimes be challenging. The effectiveness of the intravitreal drugs may decrease over time and drug switching may be necessary. In Turkey, intravitreal drugs are only approved and reimbursed for DRP patients in case of macular edema. Off-label drug use may be preferred in non-approved indications and for reasons such as the need for additional drug doses to the determined limits. However, permission must be obtained from TMMDA for off-label drug use in Turkey. Conclusion: Anti-vascular endothelial growth factor drugs are the first-line treatment options for DME. TMMDA currently approves stepwise therapy for diabetic macular edema, initiated with bevacizumab. Bevacizumab administration does not require approval for off-label application. Additionally, ranibizumab, aflibercept, and dexamethasone implant are reimbursed only in case of failure to respond to 3 doses of bevacizumab injection. Our report provides information about off-label drug preferences and drug use regulations in DRP treatment in Turkey. Abbreviations:DME = diabetic macular edema, DRP = Diabetic retinopathy, FFA = fundus fluorescein angiography, TMMDA = Turkish Medicines and Medical Devices Agency, VEGF = vascular endothelial growth factor.