Early Response to Intravitreal Dexamethasone Implant Therapy in Diabetic Macular Edema May Predict Visual Outcome

The Treatment of Diabetic Retinal Edema with Intravitreal Steroids: How and When

Diabetic macular edema (DME) is a common complication of diabetes mellitus and a leading cause of visual impairment worldwide. It is defined as the diabetes-related accumulation of fluid, proteins, and lipids, with retinal thickening, within the macular area. DME affects a significant proportion of individuals with diabetes, with the prevalence increasing with disease duration and severity. It is estimated that approximately 25-30% of diabetic patients will develop DME during their lifetime. Poor glycemic control, hypertension, hyperlipidemia, diabetes duration, and genetic predisposition are recognized as risk factors for the development and progression of DME. Although the exact pathophysiology is still not completely understood, it has been demonstrated that chronic hyperglycemia triggers a cascade of biochemical processes, including increased oxidative stress, inflammation, activation of vascular endothelial growth factor (VEGF), cellular dysfunction, and apoptosis, with breakdown of the blood-retinal barriers and fluid accumulation within the macular area. Early diagnosis and appropriate management of DME are crucial for improving visual outcomes. Although the control of systemic risk factors still remains the most important strategy in DME treatment, intravitreal pharmacotherapy with anti-VEGF molecules or steroids is currently considered the first-line approach in DME patients, whereas macular laser photocoagulation and pars plana vitrectomy may be useful in selected cases. Available intravitreal steroids, including triamcinolone acetonide injections and dexamethasone and fluocinolone acetonide implants, exert their therapeutic effect by reducing inflammation, inhibiting VEGF expression, stabilizing the blood-retinal barrier and thus reducing vascular permeability. They have been demonstrated to be effective in reducing macular edema and improving visual outcomes in DME patients but are associated with a high risk of intraocular pressure elevation and cataract development, so their use requires an accurate patient selection. This manuscript aims to provide a comprehensive overview of the pathology, epidemiology, risk factors, physiopathology, clinical features, treatment mechanisms of actions, treatment options, prognosis, and ongoing clinical studies related to the treatment of DME, with particular consideration of intravitreal steroids therapy.

Real-world effectiveness of intravitreal dexamethasone implants - Comparison between eyes eligible and ineligible for clinical trials and their associated outcomes

BACKGROUND

Concerns about the generalizability of pivotal randomized controlled trials (pRCTs) findings have been raised. We aimed to compare intravitreal dexamethasone implants' (IDIs) effectiveness for diabetic macular edema (DME) and central retinal vein occlusion (CRVO), between eyes eligible and ineligible for pRCTs.

METHODS

This retrospective cohort study analyzed Taiwan's Chang Gung Research Database, including DME or CRVO eyes initiating IDIs during 2015-2020. We classified all treated eyes as eligible or ineligible for pRCTs following major selection criteria of the MEAD and GENEVA trials, and evaluated three-, six-, and twelve-month changes in central retinal thickness (CRT) and visual acuity (VA) after initiating IDIs.

RESULTS

We included 177 IDI-treated eyes (DME: 72.3%; CRVO: 27.7%), of which 39.8% and 55.1% were ineligible for DME and CRVO pRCTs, respectively. LogMAR-VA and CRT changes at different times were comparable in DME eyes eligible (LogMAR-VA difference: 0.11 to 0.16; CRT difference: -32.7 to -96.9 μm) and ineligible (LogMAR-VA difference: -0.01 to 0.15; CRT difference: -54.5 to -109.3 μm) for the MEAD trial. By contrast, CRVO eyes ineligible for the GENEVA trial had greater LogMAR-VA changes (0.37 ~ 0.50) than those eligible (0.05 ~ 0.13), with comparable CRT reductions (eligible eyes: -72.3 to -106.4 μm; ineligible eyes: -61.8 to -110.7 μm) (all p-values <0.05 of the mean differences between eligible and ineligible CRVO eyes for all follow-ups).

CONCLUSIONS

IDIs had similar VA and CRT outcomes among DME eyes, regardless of pRCT-eligibility. However, among CRVO eyes, those ineligible for pRCTs showed greater deterioration in VA than those eligible.

Optogenetic Modulation of Intraocular Pressure in a Glucocorticoid-Induced Ocular Hypertension Mouse Model

Purpose

Steroid-induced glaucoma is a common form of secondary open angle glaucoma characterized by ocular hypertension (elevated intraocular pressure [IOP]) in response to prolonged glucocorticoid exposure. Elevated IOP occurs with increased outflow resistance and altered trabecular meshwork (TM) function. Recently, we used an optogenetic approach in TM to regulate the 5-phosphatase, OCRL, which contributes to regulating PI(4,5)P2 levels. Here, we applied this system with the aim of reversing compromised outflow function in a steroid-induced ocular hypertension mouse model.

Methods

Elevated IOP was induced by chronic subconjunctival dexamethasone injections in wild-type C57Bl/6j mice. AAV2 viruses containing optogenetic modules of cryptochrome 2 (Cry2)-OCRL-5ptase and CIBN-GFP were injected into the anterior chamber. Four weeks after viral expression and dexamethasone exposure, IOP was measured by tonometer and outflow facility was measured by perfusion apparatus. Human TM cells were treated with dexamethasone, stimulated by light and treated with rhodamine-phalloidin to analyze actin structure.

Results

Dexamethasone treatment elevated IOP and decreased outflow facility in wild-type mice. Optogenetic constructs were expressed in the TM of mouse eyes. Light stimulation caused CRY2-OCRL-5ptase to translocate to plasma membrane (CIBN-CAAX-GFP) and cilia (CIBN-SSTR3-GFP) in TM cells, which rescued the IOP and outflow facility. In addition, aberrant actin structures formed by dexamethasone treatment were reduced by optogenetic stimulation in human TM cells in culture.

Conclusions

Subcellular targeting of inositol phosphatases to remove PIP2 represents a promising strategy to reverse defective TM function in steroid-induced ocular hypertension.

Translational Relevance

Targeted modulation of OCRL may be used to decrease steroid-induced elevated IOP.

Visual Acuity Gain Profiles and Anatomical Prognosis Factors in Patients with Drug-Naive Diabetic Macular Edema Treated with Dexamethasone Implant: The NAVEDEX Study

Brief Summary Statement

NAVEDEX (NAive diabetic macular Edema treated by DEXamethasone implant) study is a real-life multi-center study on drug-naive diabetic macular edema treated by Dexamethasone-implant. Two different visual acuity gain (VA) profiles were identified, based on baseline visual acuity (VA). Baseline disorganization of retinal inner layers or ellipsoid zone alterations (EZAs) negatively influence final VA but has no impact on VA gain.

Abstract

The purpose of this study is to evaluate the visual acuity (VA) gain profiles between patients with drug-naive diabetic macular edema (DME) treated by dexamethasone implant (DEX-implant) and assess the baseline anatomical and functional factors that could influence the response to the treatment in real-life conditions. A retrospective, multi-center observational study included 129 eyes with drug-naive DME treated by DEX-implant. The Median follow-up was 13 months. Two groups of VA gain trajectories were identified—Group A, with 71% (n = 96) of patients whose average VA gain was less than five letters and Group B, with 29% (n = 33) of patients with an average gain of 20 letters. The probability of belonging to Group B was significantly higher in patients with baseline VA < 37 letters (p = 0.001). Ellipsoid zone alterations (EZAs) or disorganization of retinal inner layers (DRILs) were associated with a lower final VA (53.0 letters versus 66.4, p = 0.002) but without a significant difference in VA gain (4.9 letters versus 6.8, p = 0.582). Despite a low baseline VA, this subgroup of patients tends to have greater visual gain, encouraging treatment with DEX-implant in such advanced-stage disease. However, some baseline anatomic parameters, such as the presence of EZAs or DRILs, negatively influenced final vision.

Managing Diabetic Macular Edema in Clinical Practice: Systematic Review and Meta-Analysis of Current Strategies and Treatment Options

Purpose

This meta-analysis aims to summarize 12-month best-corrected visual acuity (BCVA) outcomes in response to anti-vascular endothelial growth factor (VEGF) therapy and dexamethasone implant for the treatment of diabetic macular edema (DME) and to identify factors affecting treatment response using evidence generated from meta-regression.

Methods

A systematic review of electronic databases was conducted to identify randomized controlled trials (RCTs) and real-life/observational studies that reported 12-month changes in BCVA in patients with DME on anti-VEGF or dexamethasone implant treatment in monotherapy. Study factors that were analyzed are baseline patient characteristics, study type, drug employed, number of injections and 12-month change in BCVA. Data were pooled in a random-effects meta-analysis with BCVA change as the main outcome. Meta-regression was conducted to assess the impact of multiple covariates.

Results

One-hundred-five heterogeneous study populations (45,032 eyes) were identified and included in the analysis. The use of anti-VEGFs and dexamethasone implant induced an overall increase of +8.13 ETDRS letters in BCVA at 12 months of follow-up. Meta-regression provided evidence that mean BCVA change using anti-VEGFs was not statistically higher for RCTs (p=0.35) compared to observational studies. Dexamethasone implant showed a trend for better results in observational studies over RCTs. Populations following a fixed aflibercept regimen performed better than those following a reactive treatment regimen. Mean BCVA gain was higher in younger populations (p<0.001), with lower baseline BCVA (p<0.0001) and longer diabetes duration (p<0.0001), receiving a higher number of injections (p<0.0001).

Conclusion

Intravitreal therapy with anti-VEGFs or dexamethasone implant produces a significant improvement in BCVA at 12 months in patients with DME. Meta-regression identified the modifiable covariates that can be targeted in order to maximize functional results.

Baseline SD-OCT characteristics of diabetic macular oedema patterns can predict morphological features and timing of recurrence in patients treated with dexamethasone intravitreal implants

AIMS

To evaluate the timing and spectral-domain optical coherence tomography (SD-OCT) features of diabetic macular oedema (DME) recurrence according to baseline OCT patterns in patients treated with dexamethasone implant (DEX-I).

METHODS

This is a retrospective observational study (72 eyes/65 patients). Best-corrected visual acuity, timing of DME recurrence, and SD-OCT pattern [intraretinal cysts (IRC), IRC plus subretinal fluid (mixed), external limiting membrane (ELM), ellipsoid (IS/OS) layer integrity] were assessed at baseline and monthly until first DME recurrence.

RESULTS

Forty-two (58.3%) and 30 (41.6%) DME eyes had an IRC and mixed DME pattern at baseline, respectively. Twenty-four out of thirty mixed eyes (80%) relapsed without subretinal fluid. At baseline, mixed eyes showed similar changes in ELM and IS/OS (60 and 76.6% of eyes, respectively) versus IRC eyes (42.8 and 80.9% of eyes). After DME recurrence, more mixed eyes at baseline showed ELM and IS/OS changes (63.3 and 86.6%) than IRC eyes (50 and 76.2%). 33.3% of mixed eyes had DME recurrence at ≥ 6 months from first DEX-I implant versus 19% of IRC eyes.

CONCLUSIONS

Mixed DME eyes were treated with DEX-I relapse later and more frequently without subretinal fluid than IRC eyes. SD-OCT characteristics of different DME patterns at baseline can predict morphological features and timing of DME recurrence.

AFLIBERCEPT FOR PERSISTENT DIABETIC MACULAR EDEMA: Forty-Eight-Week Outcomes

PURPOSE

To evaluate functional and anatomical outcomes after a switch from intravitreal bevacizumab to aflibercept in patients with persistent diabetic macular edema.

METHODS

Prospective, single-arm, open-label clinical trial of patients with persistent diabetic macular edema, despite previous treatment with bevacizumab. Five loading doses of intravitreal aflibercept were administered every 4 weeks with subsequent injections administered every 8 weeks. Patients were reviewed every 4 weeks, and best-corrected visual acuity and central macular thickness were recorded. Primary outcome measures included change in central macular thickness and best-corrected visual acuity at week 48 compared with baseline. Paired t-tests were used to assess change between baseline and follow-up visits.

RESULTS

At baseline, 43 eyes from 43 patients were recruited with a median (interquartile range) of 12 (7-24) previous intravitreal anti-vascular endothelial growth factor injections over a period of 18 (8-34) months. Mean ± SD central macular thickness reduced by 59 ± 114 μm (P = 0.002), and best-corrected visual acuity improved by 3.9 ± 7.0 letters (P = 0.001) after 48 weeks in the 41 patients who completed the trial. Best-corrected visual acuity improvements were more marked in patients who gained ≥5 letters after the first injection (8.9 ± 5.7 vs. 1.8 ± 6.5 letter gain at 48 weeks, P = 0.002), a difference which remained significant after regression analysis with baseline best-corrected visual acuity . Vision gains and central macular thickness reduction were similar in 9 fellow eyes eligible for inclusion being concurrently treated for diabetic macular edema with bevacizumab.

CONCLUSION

Intravitreal aflibercept was effective in improving anatomical and visual outcomes among patients with an incomplete response to intravitreal bevacizumab with 48 weeks of follow-up. Patients with a good early response subsequent to switching had a better improvement in vision at 48 weeks.

Dexamethasone 0.4mg Sustained-Release Intracanalicular Insert in the Management of Ocular Inflammation and Pain Following Ophthalmic Surgery: Design, Development and Place in Therapy

Inflammation and pain are two prevalent findings after ocular surgery. Corticosteroids are widely administrated as a core treatment to control post-surgical inflammation and pain. Improper patient adherence to post-operative eye drop regimens, limited bioavailability of topical eye drops, and the negative impact of preservatives used in many of these eye drops, has made a strong case for novel therapies in the treatment of post-operative pain and inflammation. This review of the literature will focus on the role of intracanalicular sustained-release dexamethasone (Dextenza, Ocular Therapeutix, Bedford, MA, USA) for the management of ocular inflammation and pain.

Long-term outcomes after intravitreal dexamethasone treatment in steroid responders

AIMS

Intravitreal steroid implants have emerged as an adjunctive therapy in diabetic macular edema (DME) in patients refractory to anti-vascular endothelial growth factor agents. However, the use of these agents in patients with a prior history of steroid-induced ocular hypertension is limited. The present study aimed to analyze long-term intraocular pressure (IOP) response to the dexamethasone implant in patients with DME and a history of steroid-induced increase in IOP.

METHODS

In a multicenter retrospective review, 17 eyes with DME and a history of steroid-induced increase in IOP to > 21 mmHg were treated with the dexamethasone implant and followed for 18 months. Patients with a history of vitrectomy of vitreoretinal interface pathology were excluded. The primary outcomes were the change in IOP and use of IOP-lowering agents.

RESULTS

Among the study population (17 eyes), there was no significant change in mean IOP from baseline through 18 months (15.9 ± 2.0-14.6 ± 2.8 mmHg; p = 0.18). The number of patients requiring IOP-lowering agents rose from 5 at baseline to 14 at 18 months (p = 0.0049). None of the study eyes required surgical treatment.

CONCLUSIONS

Though dexamethasone does predictably lead to an increase in IOP, this adverse effect was effectively managed with topical treatment. The present study suggests that the intravitreal dexamethasone implant may be considered in patients with DME and a history of steroid-induced ocular hypertension who have exhausted first-line treatments.

Diabetic macular edema: Evidence-based management

Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy with an increasing prevalence tied to the global epidemic in type 2 diabetes mellitus. Its pathophysiology starts with decreased retinal oxygen tension that manifests as retinal capillary hyperpermeability and increased intravascular pressure mediated by vascular endothelial growth factor (VEGF) upregulation and retinal vascular autoregulation, respectively. Spectral domain optical coherence tomography (SD-OCT) is the cornerstone of clinical assessment of DME. The foundation of treatment is metabolic control of hyperglycemia and blood pressure. Specific ophthalmic treatments include intravitreal anti-VEGF drug injections, intravitreal corticosteroid injections, focal laser photocoagulation, and vitrectomy, but a substantial fraction of eyes respond incompletely to all of these modalities resulting in visual loss and disordered retinal structure and vasculature visible on SD-OCT and OCT angiography. Efforts to close the gap between the results of interventions within randomized clinical trials and in real-world contexts, and to reduce the cost of care increasingly occupy innovation in the social organization of ophthalmic care of DME. Pharmacologic research is exploring other biochemical pathways involved in retinal vascular homeostasis that may provide new points of intervention effective in those cases unresponsive to current treatments.

In vivo measurement of trabecular meshwork stiffness in a corticosteroid-induced ocular hypertensive mouse model

Ocular corticosteroids are commonly used clinically. Unfortunately, their administration frequently leads to ocular hypertension, i.e., elevated intraocular pressure (IOP), which, in turn, can progress to a form of glaucoma known as steroid-induced glaucoma. The pathophysiology of this condition is poorly understood yet shares similarities with the most common form of glaucoma. Using nanotechnology, we created a mouse model of corticosteroid-induced ocular hypertension. This model functionally and morphologically resembles human ocular hypertension, having titratable, robust, and sustained IOPs caused by increased resistance to aqueous humor outflow. Using this model, we then interrogated the biomechanical properties of the trabecular meshwork (TM), including the inner wall of Schlemm's canal (SC), tissues known to strongly influence IOP and to be altered in other forms of glaucoma. Specifically, using spectral domain optical coherence tomography, we observed that SC in corticosteroid-treated mice was more resistant to collapse at elevated IOPs, reflecting increased TM stiffness determined by inverse finite element modeling. Our noninvasive approach to monitoring TM stiffness in vivo is applicable to other forms of glaucoma and has significant potential to monitor TM function and thus positively affect the clinical care of glaucoma, the leading cause of irreversible blindness worldwide.

Safety and efficacy of dexamethasone implant along with phacoemulsification and intraocular lens implantation in children with juvenile idiopathic arthritis associated uveitis

PURPOSE

To assess the safety and efficacy of intraoperative intravitreal dexamethasone implant in patients of juvenile idiopathic arthritis (JIA)-associated uveitis undergoing phacoemulsification with posterior chamber intraocular lens (PCIOL) implantation.

METHODS

Retrospectively, data of patients with JIA-associated uveitis undergoing phacoemulsification with PCIOL implantation with intraoperative dexamethasone implant injection were analyzed. Patients with a minimum follow-up of 6 months were included. Primary outcome measures were ocular inflammation, intraocular pressure (IOP), best-corrected visual acuity (BCVA), and worsening of uveitis.

RESULTS

8 eyes of 6 patients were included. BCVA was significantly improved at 1, 3, and 6 months postoperatively 0.20 ± 0.09, P = 0.008; 0.18 ± 0.11, P = 0.008; and 0.24 ± 0.11, P = 0.01, respectively. No statistical difference noted in mean IOP at various follow-up visits. None developed worsening of uveitis or Cystoid macular edema.

CONCLUSION

Intraoperative intravitreal dexamethasone implant is a safe and effective in preventing and managing the postoperative inflammation in children with JIA-associated uveitic cataract.