Intravitreal Dexamethasone Implant Switch after Anti-VEGF Treatment in Patients Affected by Retinal Vein Occlusion: A Review of the Literature

Nowadays, retinal vein occlusion (RVO) is the second most prevalent cause of vision loss associated with retinal vascular disease. Intravitreal injections are currently known as a major advancement in ophthalmology, particularly in the treatment of RVO and other retinal disorders. Particularly, the first line of therapy is usually anti-vascular endothelial growth factor (VEGF) drugs. Notably, for RVO eyes that have not responded to anti-VEGF therapy, an intravitreal dexamethasone (DEX) implant 0.7 mg (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a suitable therapeutical substitute. Actually, investigations carried out in the real world and clinical trials have shown the safety and the efficacy of intravitreal DEX implants for treating this retinal disease. For this reason, choosing patients carefully may thus be essential to reduce the number of injections that clinics and hospitals have to do to manage RVO and its complications. The primary aim of this review is to summarize the pathophysiology of this retinal vascular disease, as well as the clinical and ocular imaging features that may support a switch from prior anti-VEGF treatment to intravitreal DEX implant, to provide the RVO patients with the best possible treatment to ensure maximum visual recovery.

Efficacy of single-dose intravitreal dexamethasone implantation for retinal vein occlusion patients with refractory macular edema: A systematic review and meta-analysis

Purpose: To assess the functional and anatomical consequences of single-dose dexamethasone (DEX) implants for the treatment of refractory macular edema (ME) secondary to retinal vein occlusion (RVO) after anti-vascular endothelial growth factor agents.

Methods: A literature search of studies on switching therapy to DEX implants from anti-VEGF agents in refractory RVO patients was performed with five electronic databases (PubMed, Embase, Web of Science, MEDLINE, and Cochrane Library) prior to January 2022. The main outcomes included best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes at different follow-up endpoints from baseline. All analyses were performed using Stata version 15.0.

Results: The final analysis included four eligible studies with a total of 99 patients. After single-dose DEX implant application, BCVA improved significantly at 2, 3, and 6 months with an average gain of −0.23 logarithm of the minimum angle of resolution (logMAR) (p = 0.004), −0.20 logMAR (p = 0.027), and -0.09 logMAR (p = 0.021), respectively. Mean CMT reduction was also significant from baseline to 2 months (-241.89 μm, p < 0.001), 3 months (−222.61 μm, p < 0.001), and 6 months (−90.49 μm, p < 0.001). No serious adverse events were observed in any of the included studies.

Conclusion: This meta-analysis showed that RVO patients with refractory ME could benefit significantly from switching therapy to DEX implantation, with efficacy lasting 6 months after a single-dose application. Intravitreal DEX implantation is a safe and effective option for refractory cases.

Association between Obstetric Complications and Intravitreal Anti-Vascular Endothelial Growth Factor Agents or Intravitreal Corticosteroids

This nationwide population-based cohort study aimed to describe the use of intravitreal injections (IVTs) of anti-vascular endothelial growth factor (anti-VEGF) agents and corticosteroids in pregnant women in France and to report on the incidence of obstetric and neonatal complications. All pregnant women in France who received any anti-VEGF or corticosteroid IVT during pregnancy or in the month preceding pregnancy from 1 January 2009 to 31 December 2018 were identified in the national medico-administrative databases. Between 2009 and 2018, there were 5,672,921 IVTs performed in France. Among these IVTs, 228 anti-VEGF or corticosteroid IVTs were administered to 139 women during their pregnancy or in the month preceding their pregnancy. Spontaneous abortion or the medical termination of pregnancy occurred in 10 women (16.1%) who received anti-VEGF agents and in one (3.1%) of the women who received corticosteroids (p = 0.09). This is the first national cohort study of pregnant women treated with anti-VEGF or corticosteroid IVTs. We found a high incidence of obstetric complications in pregnant women treated with anti-VEGF or corticosteroid IVTs but could not demonstrate a statistically significant association between the intravitreal agents and these complications. These agents should continue to be used with great caution in pregnant women.

Effect of Alternate Treatment with Intravitreal Corticosteroid and Anti-VEGF for Macular Edema Secondary to Retinal Vein Occlusion

Purpose

To evaluate whether treatment with intravitreal corticosteroid and anti-vascular endothelial growth factor (VEGF) injections alternately can improve treatment outcomes of macular edema (ME) caused by retinal vein occlusion (RVO).

Methods

This dual-center retrospective study included 112 eyes with treatment-naïve ME secondary to RVO that were alternately treated with intravitreal corticosteroid and anti-VEGF injections (33 eyes, alternate group) or treated only with intravitreal anti-VEGF injections (79 eyes, anti-VEGF group) on a pro re nata basis.

Results

During the 12-month follow-up period, the alternate group achieved a visual acuity gain of 0.39 logMAR, while the anti-VEGF group achieved a gain of 0.21 logMAR (P=0.042). The alternate group demonstrated a reduction in the central macular thickness of 229.9-μm, while the anti-VEGF group achieved a reduction of 220.1 μm (P=0.887). The alternate group required an average of 5.2 injections, while the anti-VEGF received 4.2 injections (P < 0.001). In a propensity score-matched cohort to compensate for the differences in the injection numbers between the two groups, the alternate group achieved a better visual acuity gain than the anti-VEGF group at month 12 (0.39 logMAR vs. 0.17 logMAR, P=0.048).

Conclusions

In ME secondary to RVO, treatment with intravitreal corticosteroid and anti-VEGF injections alternately resulted in a more favorable visual outcome compared with intravitreal anti-VEGF monotherapy.

The correlation between cytokine levels in the aqueous humor and the prognostic value of anti-vascular endothelial growth factor therapy for treating macular edema resulting from retinal vein occlusion

PURPOSE

To determine the correlation between aqueous humor cytokine levels and the prognostic value of anti-vascular endothelial growth factor (VEGF) therapy for treating macular edema resulting from retinal vein occlusion (RVO-ME).

METHODS

This prospective study included 47 RVO-ME and 32 senile cataract cases. Aqueous humor collection was performed in patients with RVO-ME before intravitreal injection of ranibizumab and in patients before cataract surgery. VEGF, monocyte chemotactic protein 1 (MCP-1), interleukin (IL)-8, IL-6, basic fibroblast growth factor (b-FGF), and tumor necrosis factor-α (TNF-α) levels were measured in the aqueous humor. Central retinal thickness (CRT) was measured before ranibizumab treatment and during each follow-up visit. The recovery rate following ranibizumab treatment was calculated as (CRT_BT-CRT_AT1W)/CRT_BT, in which CRT_BT was the CRT measured before treatment and CRT_AT1W was measured 1 week after treatment. The recurrence time of RVO-ME was recorded.

RESULTS

VEGF, MCP-1, IL-8, and IL-6 levels in the aqueous humor of patients with RVO-ME were significantly higher compared with control and were positively correlated with the CRT_BT. Ranibizumab significantly reduced CRT, and VEGF levels positively correlated with the recovery rate. The mean recurrence time of RVO-ME was 43.5 days. IL-6 levels negatively correlated with the recurrence time of ME.

CONCLUSION

VEGF, MCP-1, IL-8, and IL-6 levels were significantly increased in patients with RVO-ME and were positively correlated with ME. Higher VEGF levels were indicative of CRT recovery, and higher IL-6 levels were indicative of ME recurrence after ranibizumab treatment.

Real-life medium term follow-up data for intravitreal dexamethasone implant in retinal vein occlusion

Macular edema (ME) is the most frequent vision threatening consequence after retinal vein occlusion (RVO). In this study, we evaluate the effect of dexamethasone intravitreal implants (DII, Ozurdex) in a real-life cohort of 99 patients with ME due to RVO. All patients who received DII for ME following RVO between 2011 and 2016 at the University Eye Hospital Freiburg, Germany and who had fully accessible electronic medical records were eligible for this study. Most of the patients included in this study were not treatment-naïve: 61 eyes had received prior anti-VEGF drugs, 6 eyes had received intravitreal corticosteroids (triamcinolone) and 15 had been treated with both; 17 eyes were treatment-naïve. Mean follow-up was 312 ± 310 days. Mean visual acuity (VA) was maintained throughout the observation period (mean VA at baseline: 66.7 ± 23.5 letters; at last observation 64.9 ± 28.3). Central retinal thickness (CRT) decreased from 526 ± 179 µm at baseline to 431 ± 199 µm. Mean intraocular pressure (IOP) increased from 14.4 ± 3.1 mmHg at baseline to 17.1 ± 6.3 mmHg. Cataract surgery was performed in 22% of phakic eyes. DII was used as second-line treatment in the majority of cases in this cohort. The fact that mean VA remained unchanged while mean CRT decreased illustrates that morphologic improvement does not always translate into functional gain. Mean IOP was maintained within normal limits and cataract formation was as expected in this age group.

Anti-vascular endothelial growth factor for macular oedema secondary to branch retinal vein occlusion

BACKGROUND

Branch retinal vein occlusion (BRVO) is one of the most commonly occurring retinal vascular abnormalities. The most common cause of visual loss in people with BRVO is macular oedema (MO). Grid or focal laser photocoagulation has been shown to reduce the risk of visual loss. Limitations to this treatment exist, however, and newer modalities may have equal or improved efficacy. Antiangiogenic therapy with anti-vascular endothelial growth factor (anti-VEGF) has recently been used successfully to treat MO resulting from a variety of causes.

OBJECTIVES

To investigate the efficacy and gather evidence from randomised controlled trials (RCTs) on the potential harms of anti-vascular endothelial growth factor (VEGF) agents for the treatment of macular oedema (MO) secondary to branch retinal vein occlusion (BRVO).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 6); MEDLINE Ovid; Embase Ovid; the ISRCTN registry; ClinicalTrials.gov; and the WHO ICTRP. The date of the last search was 12 June 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) investigating BRVO. Eligible trials had to have at least six months' follow-up where anti-VEGF treatment was compared with another treatment, no treatment, or placebo. We excluded trials where combination treatments (anti-VEGF plus other treatments) were used; and trials that investigated the dose and duration of treatment without a comparison group (other treatment/no treatment/sham).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data using standard methodological procedures expected by Cochrane. The primary outcome was the proportion of participants with an improvement from baseline in best-corrected visual acuity of greater than or equal to 15 letters (3 lines) on the Early Treatment in Diabetic Retinopathy Study (ETDRS) Chart at six months and 12 months of follow-up. The secondary outcomes were the proportion of participants who lost greater than or equal to 15 ETDRS letters (3 lines) and the mean visual acuity (VA) change at six and 12 months, as well as the change in central retinal thickness (CRT) on optical coherence tomography from baseline at six and 12 months. We also collected data on adverse events and quality of life (QoL).

MAIN RESULTS

We found eight RCTs of 1631 participants that met the inclusion criteria after independent and duplicate review of the search results. These studies took place in Europe, North America, Eastern Mediterranean region and East Asia. Included participants were adults aged 18 or over with VA of 20/40 or worse. Studies varied by duration of disease but permitted previously treated eyes as long as there was sufficient treatment-free interval. All anti-VEGF agents (bevacizumab, ranibizumab and aflibercept) and steroids (triamcinolone and dexamethasone) were included. Overall, we judged the studies to be at moderate or unclear risk of bias. Four of the eight studies did not mask participants or outcome assessors, or both. One trial compared anti-VEGF to sham. At six months, eyes receiving anti-VEGF were significantly more likely to have a gain of 15 or more ETDRS letters (risk ratio (RR) 1.72, 95% confidence interval (CI) 1.19 to 2.49; 283 participants; moderate-certainty evidence). Mean VA was better in the anti-VEGF group at six months compared with control (mean difference (MD) 7.50 letters, 95% CI 5.29 to 9.71; 282 participants; moderate-certainty evidence). Anti-VEGF also proved more effective at reducing CRT at six months (MD -57.50 microns, 95% CI -108.63 to -6.37; 281 participants; lower CRT is better; moderate-certainty evidence). There was only very low-certainty evidence on adverse effects. There were no reports of endophthalmitis. Mean change in QoL (measured using the National Eye Institute Visual Functioning Questionnaire VFQ-25) was better in people treated with anti-VEGF compared with people treated with sham (MD 7.6 higher score, 95% CI 4.3 to 10.9; 281 participants; moderate-certainty evidence). Three RCTs compared anti-VEGF with macular laser (total participants = 473). The proportion of eyes gaining 15 or more letters was greater in the anti-VEGF group at six months (RR 2.09, 95% CI 1.44 to 3.05; 2 studies, 201 participants; moderate-certainty evidence). Mean VA in the anti-VEGF groups was better than the laser groups at six months (MD 9.63 letters, 95% CI 7.23 to 12.03; 3 studies, 473 participants; moderate-certainty evidence). There was a greater reduction in CRT in the anti-VEGF group compared with the laser group at six months (MD -147.47 microns, 95% CI -200.19 to -94.75; 2 studies, 201 participants; moderate-certainty evidence). There was only very low-certainty evidence on adverse events. There were no reports of endophthalmitis. QoL outcomes were not reported. Four studies compared anti-VEGF with intravitreal steroid (875 participants). The proportion of eyes gaining 15 or more ETDRS letters was greater in the anti-VEGF group at six months (RR 1.67, 95% CI 1.33 to 2.10; 2 studies, 330 participants; high-certainty evidence) and 12 months (RR 1.76, 95% CI 1.36 to 2.28; 1 study, 307 participants; high-certainty evidence). Mean VA was better in the anti-VEGF group at six months (MD 8.22 letters, 95% CI 5.69 to 10.76; 2 studies, 330 participants; high-certainty evidence) and 12 months (MD 9.15 letters, 95% CI 6.32 to 11.97; 2 studies, 343 participants; high-certainty evidence). Mean CRT also showed a greater reduction in the anti-VEGF arm at 12 months compared with intravitreal steroid (MD -26.92 microns, 95% CI -65.88 to 12.04; 2 studies, 343 participants; moderate-certainty evidence). People receiving anti-VEGF showed a greater improvement in QoL at 12 months compared to those receiving steroid (MD 3.10, 95% CI 0.22 to 5.98; 1 study, 307 participants; moderate-certainty evidence). Moderate-certainty evidence suggested increased risk of cataract and raised IOP with steroids. There was only very low-certainty evidence on APTC events. No cases of endophthalmitis were observed.

AUTHORS' CONCLUSIONS

The available RCT evidence suggests that treatment of MO secondary to BRVO with anti-VEGF improves visual and anatomical outcomes at six and 12 months.

Comparison of intravitreal dexamethasone implant and anti-VEGF drugs in the treatment of retinal vein occlusion-induced oedema: a meta-analysis and systematic review

OBJECTIVE

To compare the efficacy and safety of intravitreal dexamethasone (DEX) implant and anti-vascular endothelial growth factor (anti-VEGF) agents in the treatment of macular oedema secondary to retinal vein occlusion (RVO).

DESIGN

Systematic review and meta-analysis based on Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DATA SOURCES

PubMed, Cochrane Library and ClinicalTrials.gov registry were searched from inception to 10 December 2019, without language restrictions.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) and real-world observation studies comparing the efficacy of DEX implant and anti-VEGF agents for the treatment of patients with RVO, naïve or almost naïve to both arms, were included.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data for mean changes in best-corrected visual acuity (BCVA), central subfield thickness (CST) and product safety. Review Manager V.5.3 and GRADE were used to synthesise the data and validate the evidence, respectively.

RESULTS

Four RCTs and 12 real-world studies were included. An average lower letter gain in BCVA was determined for the DEX implant (mean difference (MD) = -6.59; 95% CI -8.87 to -4.22 letters) administered at a retreatment interval of 5-6 months. Results were similar (MD_{6 months}=-12.68; 95% CI -21.98 to -3.37 letters; MD_{12 months}=-9.69; 95% CI -12.01 to -7.37 letters) at 6 and 12 months. The DEX implant resulted in comparable or marginally less CST reduction at months 6 and 12 but introduced relatively higher risks of elevated intraocular pressure (RR=3.89; 95% CI 2.16 to 7.03) and cataract induction (RR=5.22; 95% CI 1.67 to 16.29). Most real-life studies reported an insignificant numerical gain in letters for anti-VEGF drugs relative to that for DEX implant. However, the latter achieved comparable efficacy with a 4-month dosage interval.

CONCLUSION

Compared with anti-VEGF agents, DEX implant required fewer injections but had inferior functional efficacy and safety. Real-life trials supplemented the efficacy data for DEX implant.

Comparison between intravitreal bevacizumab and posterior sub-tenon injection of triamcinolone acetonide in macular edema secondary to retinal vein occlusion

Aim

To compare the efficacy and safety between posterior sub-tenon injection of triamcinolone acetonide (PSTA) and intravitreal injection of bevacizumab (Avastin) (IVIA) in the treatment of macular edema secondary to retinal vein occlusion.

Patients and methods

A total of 45 eyes were retrospectively enrolled (23 eyes with intravitreal bevacizumab and 22 eyes with posterior sub-tenon triamcinolone acetonide). Main endpoints included logMAR of best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP) before and after treatment at 6 months.

Results

The mean logMAR improved from 0.78 to 0.56 at 6 months for intravitreal bevacizumab (p=0.001), and from 0.91 to 0.79 and 0.87 at 3 and 6 months (p=0.038 and 0.13), respectively, for sub-tenon triamcinolone acetonide. At 6 months, the BCVA was significantly better in the bevacizumab group (p=0.02). Both groups' mean CMT significantly improved, from 478 µm at baseline to 295 µm at 6 months in IVIA group (p<0.001) and from 419 µm at baseline to 350 µm in PSTA group (p=0.012); however, this was not different between the groups at 6 months (p=0.065). Recurrence of macular edema was not different between the groups either (p=0.08). Poorer final vision was associated with poorer baseline BCVA and diagnosis of central retinal vein occlusion after adjustment for age and sex (p<0.001 and 0.012, respectively). Significant elevation of IOP was noted at 3 months in the PSTA group, but declined at 6 months compared with baseline (p=0.002 and 0.41, respectively).

Conclusion

Intravitreal bevacizumab seemed to achieve better visual acuity compared with posterior sub-tenon injections of triamcinolone acetonide at 6 months, while CMT was comparable. PSTA still resulted in transient IOP elevation.

Switch of Intravitreal Therapy for Macular Edema Secondary to Retinal Vein Occlusion from Anti-VEGF to Dexamethasone Implant and Vice Versa

PURPOSE

To evaluate the anatomical and functional outcome of intravitreal dexamethasone implant for macular edema secondary to central (C) or branch (B) retinal vein occlusion (RVO) in patients with persistent macular edema (ME) refractory to intravitreal antivascular endothelial growth factor (VEGF) treatment compared to treatment naïve patients and to dexamethasone-refractory eyes switched to anti-VEGF.

METHODS

Retrospective, observational study including 30 eyes previously treated with anti-VEGF (8 CRVO, 22 BRVO, mean age 69 ± 10 yrs), compared to 11 treatment naïve eyes (6 CRVO, 5 BRVO, 73 ± 11 yrs) and compared to dexamethasone nonresponders (2 CRVO, 4 BRVO, 69 ± 12). Outcome parameters were change in best-corrected visual acuity (BCVA) and central foveal thickness (CFT) measured by spectral-domain optical coherence tomography.

RESULTS

Mean BCVA improvement after switch to dexamethasone implant was 4 letters (p = 0.08), and treatment naïve eyes gained 10 letters (p = 0.66), while we noted no change in eyes after switch to anti-VEGF (p = 0.74). Median CFT decrease was most pronounced in treatment naïve patients (-437 μm, p = 0.002) compared to anti-VEGF refractory eyes (-170 μm, p = 0.003) and dexamethasone-refractory eyes (-157, p = 0.31).

CONCLUSIONS

Dexamethasone significantly reduced ME secondary to RVO refractory to anti-VEGF. Functional gain was limited compared to treatment naïve eyes, probably due to worse BCVA and CFT at baseline in treatment naïve eyes.

Short-term outcomes in patients with branch retinal vein occlusion who received intravitreal aflibercept with or without intravitreal ranibizumab

Purpose

The purpose of this study was to determine the short-term outcomes for patients who received intravitreal aflibercept (IVA) with or without intravitreal ranibizumab (IVR) for macular edema (ME) due to branch retinal vein occlusion (BRVO).

Patients and methods

Patients received IVA for ME due to BRVO. Patients who initially received IVA were defined as the treatment-naïve group and those who were switched from IVR to IVA after ME recurrence were defined as the switching group. Patient outcomes were examined at 1 week and 1 month postinjection.

Results

Both groups comprised 27 eyes from 27 patients. There was a significant decrease in central macular thickness (CMT) at 1 week and 1 month postinjection in both groups. There was also a significant improvement in best-corrected visual acuity (BCVA) at 1 week and 1 month postinjection in the treatment-naïve group and 1 month in the switching group. Younger age was associated with a good BCVA at 1 month postinjection in the switching group, and the absence of epiretinal membrane was associated with a reduction in CMT at 1 month postinjection in the switching group.

Conclusion

IVA is temporarily effective for treating ME due to BRVO regardless of a history of IVR use.

Comparison between "early" or "late" intravitreal injection of dexamethasone implant in branch (BRVO) or central (CRVO) retinal vein occlusion: six-months follow-up

AIM

The aim of this study was to compare early and late injections of intravitreal dexamethasone implant in patients affected by central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO) with a six-months follow-up. We assessed whether an earlier treatment start (within seven days from diagnosis) could be more beneficial than a delayed (or late) treatment start (after seven days).

MATERIALS AND METHODS

The study included 81 patients (81 eyes) affected by retinal vein occlusion. Best corrected visual acuity was assessed through Early Treatment Diabetic Retinopathy Study (ETDRS) while central macular thickness (CMT) was measured by spectral-domain optical coherence tomography.

RESULTS

Both types of patients had a positive therapeutic response to dexamethasone, with an increase in visual acuity (ETDRS) and CMT reduction. CRVO patients were characterized by lower ETDRS values at baseline and at the end of the follow-up as compared to BRVO. CRVO patients showed higher CMT values at baseline, after three and six months from injection. No significant differences in therapeutic response to dexamethasone were observed between patients treated early or late, regardless of RVO type.

CONCLUSIONS

This study demonstrates that the therapeutic properties of dexamethasone implant are not significantly influenced by an early or late treatment start in patients affected by BRVO and CRVO, although its therapeutic efficacy seems greater in the former type.