Efficacy of dexamethasone intravitreal implant for the treatment of persistent diffuse diabetic macular edema

Persistent diabetic macular edema: Definition, incidence, biomarkers, and treatment methods

Intravitreal antivascular endothelial growth factor (anti-VEGF) treatment has drastically improved the visual and anatomical outcomes in patients with diabetic macular edema (DME); however, success is not always guaranteed, and a proportion of these eyes demonstrate persistent DME (pDME) despite intensive treatment. While standardized criteria to define these treatment-resistant eyes have not yet been established, many studies refer to eyes with no clinical response or an unsatisfactory partial response as having pDME. A patient is considered to have pDME if the retinal thickness improves less than 10-25% after 6 months of treatment. A range of treatment options have been recommended for eyes with pDME, including switching anti-VEGF agents, using corticosteroids and/or antioxidant drugs in adjunct with anti-VEGF therapy, and vitrectomy. In addition, multimodal imaging of DME eyes may be advantageous in predicting the responsiveness to treatment; this is beneficial when initiating alternative therapies. We explore the literature on persistent DME regarding its defining criteria, incidence, the baseline biological markers that may be useful in anticipating the response to treatment, and the available treatment options.

Efficacy and safety of single-dose dexamethasone implantation for patients with persistent diabetic macular edema: a systematic review and meta-analysis

PURPOSE

This meta-analysis was conducted to evaluate the efficacy and safety of single-dose dexamethasone implantation for treating persistent DME (diabetic macular edema) refractory to anti-VEGF (anti-vascular endothelial growth factor) drugs over a period of 6 months.

METHODS

All related clinical trials were reviewed by searching electronic databases of PubMed, Medline, Web of Science, Cochrane Library, and EMBASE. The primary outcome parameters were best-corrected visual acuity (BCVA) and central macular thickness (CMT). We performed this meta-analysis by using Stata15.0.

RESULTS

Ten clinical trials involving 362 eyes from 328 patients were eligible in the final analysis. After single-dose dexamethasone implantation, there was a significant improvement in BCVA from baseline to 1, 3, and 6 months with an average increase of - 0.15 logMAR (p < 0.001), - 0.14 logMAR (p < 0.001), and - 0.07 logMAR (p = 0.004), respectively. Further, mean CMT decreased significantly with an average reduction of 249.18 μm (p < 0.001), 217.66 μm (p < 0.001), and 91.56 μm (p < 0.001) at months 1, 3, and 6, respectively.

CONCLUSIONS

Our results indicate that switching to a dexamethasone implant could achieve significant anatomical and functional improvement among patients with refractory DME. Clinicians should be aware of this treatment option in refractory DME.

Noninvasive monitoring of suprachoroidal, subretinal, and intravitreal implants using confocal scanning laser ophthalmoscope (cSLO) and optical coherence tomography (OCT)

To address the need for noninvasive monitoring of injectable preformed drug delivery implants in the eye, we developed noninvasive methods to monitor such implants in different locations within the eye. Cylindrical polymeric poly(lactide-co-glycolide) or metal implants were injected into isolated bovine eyes at suprachoroidal, subretinal, and intravitreal locations and imaged noninvasively using the cSLO and OCT modes of a Heidelberg Spectralis HRA + OCT instrument after adjusting for the corneal curvature. Length and diameter of implants were obtained using cSLO images for all three locations, and the volume was calculated. Additionally, implant volume for suprachoroidal and subretinal location was estimated by integrating the cross-sectional bleb area over the implant length in multiple OCT images or using the maximum thickness of the implant based on thickness map along with length in cSLO image. Simultaneous cSLO and OCT imaging identified implants in different regions of the eye. Image-based measurements of implant dimensions mostly correlated well with the values prior to injection using blade micrometer. The accuracy (82-112%) and precision (1-19%) for noninvasive measurement of length was better than the diameter (accuracy 69-130%; precision 3-38%) using cSLO image for both types of implants. The accuracy for the measurement of volume of both types of implants from all three intraocular locations was better with cSLO imaging (42-152%) compared to those obtained using OCT cross-sectional bleb area integration (117-556%) or cSLO and thickness map (32-279%) methods. Suprachoroidal, subretinal, and intravitreal implants can be monitored for length, diameter, and volume using cSLO and OCT imaging. Such measurements may be useful in noninvasively monitoring implant degradation and drug release in the eye.

Assessment of Inflammation Biomarkers in Diabetic Macular Edema Treated with Intravitreal Dexamethasone Implant

Purpose: To evaluate inflammation biomarkers in diabetic macular edema (DME) treated with intravitreal dexamethasone implant (Ozurdex^®). Methods: This retrospective single-center study investigated 64 eyes of 64 patients with DME who were nonresponsive to prior antivascular endothelial growth factor and treated with intravitreal Ozurdex. The neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR), and platelet/lymphocyte ratio were calculated. Visual acuity and optical coherence tomography markers, including hyper-reflective dots and subretinal fluid (SRF), were determined, and central retinal thickness was also evaluated monthly for 3 months. Results: The average age was 64.06 ± 7.81 (48-84) years. The baseline NLR and MLR were significantly higher in patients with better visual outcomes (P = 0.029 and P = 0.048, respectively). Better anatomical outcomes were observed in the presence of SRF (P = 0.027). No significant differences were observed in the rates of the presence of SRF and hyper-reflective points about the better functional outcome (P > 0.05). Conclusions: SRF as an imaging biomarker, and NLR and MLR as blood biomarkers, stand out as markers of inflammation and were found to be associated with better response to Ozurdex implantation in DME.

Outcome of Single Dexamethasone Implant Injection in the Treatment of Persistent Diabetic Macular Edema After Anti-VEGF Treatment: Real-Life Data from a Tertiary Hospital in Jordan

Purpose

To analyze the real-life clinical outcome of a single dexamethasone implant (DEX) injection in the treatment of persistent diabetic macular edema (DME) after anti-vascular endothelial growth factor (anti-VEGF) agents in a sample of the Jordanian population.

Methods

An observational case study design that involved a retrospective chart review analysis in a tertiary hospital in Amman, Jordan. Patients who showed persistent DME after receiving at least six doses of anti-VEGF agents for DME treatment were included.

Results

The study population consisted of 72 participants (29 females, 43 males) having an average age of 66 years. All patients had best-corrected visual acuity (BCVA) less than 0.7 (6/9) and SD-OCT documented center-involved DME. The study results showed that the average baseline BCVA improved from 0.205±0.1 before DEX injection to 0.358±0.1 at 3 months post-injection (p<0.0001). The central mean thickness (CMT) showed significant improvement also (539.347±132.402 to 379.041±99.430, p<0.0001). There was a mean of 3 mmHg increase in intraocular pressure at 3 months post-injection (p<0.0001), however, only 4% of patients required medical treatment. Other inflammatory biomarkers in OCT, such as intraretinal hyper-reflective dots (HRD), showed significant improvement also (23.67±16 to 14.83±13, p<0.0001). No other significant safety concerns were noticed.

Conclusion

A single DEX injection showed significant clinical and anatomical improvement in DME cases that are persistent after anti-VEGF treatment in our sample, with an excellent safety profile. In case of supply shortage of intravitreal injections, which occurs frequently at our center, a single DEX injection may be utilized as an effective DME therapy. Further research is mandated to identify clinical response in a larger sample and more frequent injections.

A Collaborative Retrospective Study on the Efficacy and Safety of Intravitreal Dexamethasone Implant (Ozurdex) in Patients with Diabetic Macular Edema: The European DME Registry Study

PURPOSE

To evaluate the efficacy, effect profile, and safety of dexamethasone implant on diabetic macular edema (DME) in a real-life setting, further comparing results by DME duration, previous treatment status, and diabetic control.

DESIGN

A multicenter, retrospective cohort of 340 DME eyes of 287 patients from 25 clinical sites from 8 countries.

METHODS

Data were analyzed in 2 perspectives: per injection, in which all measurements were grouped and baseline was defined as the day of injection, and thus the pharmacodynamics of single injections could be assessed; and injection series, defined as 2 or more injections with 3 to 6 months between injections analyzing the outcome 3 to 6 months after the last injection.

MAIN OUTCOME MEASURES

Primary outcome was improvement of 15 or more letters in best-corrected visual acuity (BCVA) from baseline. Secondary outcomes included improvement of 10 letters or more in BCVA, change in central macular thickness (CMT), and time to maximum improvement and safety.

RESULTS

Overall, 762 injections were administered to 340 eyes of 287 patients. Injection series analysis included 171 series in 171 eyes of 150 patients, for a total of 444 injections, with a mean follow-up of 1.7±0.8 years. Of the 762 injections analyzed per injection, 22.7% achieved a 15-letter or more improvement, and 37.8% achieved a 10-letter or more improvement. Mean time to peak improvement was 81.9±39.7 days. Mean maximum change in CMT was -174±171 μm. Overall, 7.6% lost 15 or more letters. More eyes with early DME gained 10 or more letters and fewer eyes lost 10 or more letters compared with eyes with late DME (47.4% vs. 33.9% [P = 0.001] and 8.2% vs. 13.5% [P = 0.029], respectively). Patients with controlled diabetes showed greater CMT reduction (P = 0.0002). A higher percentage of treatment-naive patients gained 10 or 15 letter or more in BCVA (P = 0.001 and P = 0.006, respectively). Intraocular pressure elevation of more than 25 mmHg was found following 7.9% of injections; no endophthalmitis was reported.

CONCLUSIONS

Dexamethasone implant is an effective and safe treatment for DME. Peak improvement was achieved 3 months after injection and dissipated thereafter. Clinicians and providers may consider shortening treatment intervals.

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.

Pharmacological Management of Diabetic Macular Edema in Real-Life Observational Studies

OBJECTIVES OF THE STUDY

of observational studies concerning the pharmacological management of diabetic macular edema (DME).

METHODS

A literature review was conducted using the PubMed database on 1 February 2018 to identify studies evaluating the efficacy of anti-VEGF and dexamethasone (DEX) implants for DME. Studies with more than 10 patients and follow-up of more than 6 months were selected. Analyses were carried out on the overall population and on subgroups defined according to baseline visual acuity (BVA) and the patients' naïve or non-naïve status.

RESULTS

Thirty-two studies evaluating the efficacy of anti-VEGF and 31 studies evaluating the efficacy of DEX-implants were retained, concerning 6,842 and 1,703 eyes, respectively. A mean gain of +4.7 letters for a mean of 5.8 injections (mean follow-up: 15.6 months) and +9.6 letters for a mean of 1.6 injections (10.3 months) was found in the anti-VEGF and DEX-implant studies, respectively. Final VA appears to be similar for both treatment (62 letters for anti-VEGF, 61.2 letters for DEX-implant), and BVA appears lower for DEX-implant, which may partially explain the greater visual gain. The DEX-implant studies show greater gains in VA compared to the anti-VEGF studies, especially for higher BVA. Indeed, mean gains for the subgroups of patients with BVA<50 letters, 5060 letters are +4.3, +5.8, and +3.1 letters, respectively, in the anti-VEGF studies and +10.5, +9.3, and +8.8 letters, respectively, in the DEX-implant studies. Regarding the patient's initial status, only naïve status appears to confer the best functional response in DEX-implant studies.

CONCLUSION

Observational studies investigating DEX-implant report clinically similar final VA when compared to anti-VEGF, but superior visual gains in real-life practice. This latter difference could be due to the better BVA, but also to the fact that less injections were administered in the anti-VEGF observational studies than in the interventional studies.

INTRAVITREAL DEXAMETHASONE IMPLANTATION IN PATIENTS WITH DIFFERENT MORPHOLOGICAL DIABETIC MACULAR EDEMA HAVING INSUFFICIENT RESPONSE TO RANIBIZUMAB

PURPOSE

To evaluate the effectiveness of a single intravitreal injection of dexamethasone implant in resistant diabetic macular edema that have different morphological types.

METHODS

In this retrospective study, 31 patients (35 eyes) with persistent diabetic macular edema, who underwent a single injection of dexamethasone implant, were evaluated. Diabetic macular edema was classified into three types: diffuse retinal thickening (n = 10), cystoid macular edema (n = 13), and serous retinal detachment (n = 12). Primary outcome measures were best corrected visual acuity, and central macular thickness.

RESULTS

The three subgroups were similar in terms of age and gender (P > 0.05). Total duration of diabetes was significantly less in the serous retinal detachment subgroup (P = 0.01). There were no differences in the best corrected visual acuity between the three subgroups until the sixth month. However, the best corrected visual acuity was significantly better in the diffuse retinal thickness subgroup at the sixth month (P = 0.008). Regarding the central macular thickness values, it was statistically better in serous retinal detachment than in diffuse retinal thickening and cystoid macular edema subgroups till the sixth month (P = 0.001). However, at the sixth month, there was not any statistical difference between subgroups regarding central macular thickness values. Antiglaucomatous agents were required in 4 (11.4%) patients throughout the study.

CONCLUSION

Treatment algorithms should differ according to the morphology of diabetic macular edema; however, more data is needed to give specific recommendations.

Repeated Dexamethasone Intravitreal Implant for the Treatment of Diabetic Macular Oedema Unresponsive to Anti-VEGF Therapy: Outcome and Predictive SD-OCT Features

PURPOSE

To investigate dexamethasone intravitreal implant 0.7 mg (DEX implant) for the treatment of diabetic macular oedema (DME) refractory to anti-vascular endothelial growth factor (anti-VEGF) therapy and evaluate predictive factors.

METHODS

Two-centre retrospective interventional case series, including 40 eyes of 31 patients treated with DEX implant for at least 2 consecutive cycles.

RESULTS

Mean ± SD intervals from implantation to recurrence in the first (4.2 ± 1.0 months) and second cycles (4.0 ± 0.9 months) were not significantly different. Best corrected visual acuity improved significantly (p < 0.001) by 7.0 ± 8.4 letters from baseline to month 2, and by 5.1 ± 6.9 letters between the first and second cycles. Central retinal thickness reduction 2 months after implantation was greater after the first (-194 ± 172 µm) than the second cycle (-134 ± 150 µm). Ellipsoid zone-external limiting membrane (EZ-ELM) disruption score decreased from 1.39 ± 1.16 at baseline to 1.24 ± 1.16 (p = 0.0832) after cycle 1 and remained stable 2 months after cycle 2. Eyes with persisting severe EZ-ELM disruption (score >2, n = 10) 2 months after the first DEX implant showed significantly (p = 0.0153) smaller visual acuity (VA) gains than eyes with less severe (score ≤2) EZ-ELM disruption.

CONCLUSION

Repeated intravitreal DEX injections with average intervals of 4 months are valuable in patients with DME refractory to anti-VEGF therapy. Disorganization of outer retinal layers (EZ-ELM) may predict smaller VA gains if evaluated after initial reduction of macular oedema.