Dexamethasone intravitreal implant for treatment of diabetic macular edema in vitrectomized patients. Retina. 2011;31:915-923. [PMID: 21487341 DOI: 10.1097/iae.0b013e318206d18c]

Dexamethasone intravitreal implant in vitrectomized versus nonvitrectomized eyes for treatment of patients with persistent diabetic macular edema

PURPOSE

To compare the 6-month anatomic and best-corrected visual acuity (BCVA) response after sustained-release dexamethasone (DEX) intravitreal implant between nonvitrectomized and vitrectomized eyes with persistent diabetic macular edema (DME).

METHODS

Retrospective, comparative, and consecutive review of the medical records of 58 patients with decreased visual acuity, due to refractory DME, who underwent a single injection of Ozurdex between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain. Then, we divided patients into 2 groups: 24 eyes who had undergone standard pars plana vitrectomy (vitrectomized group), and 34 eyes that were not operated on (nonvitrectomized group). Outcomes measured were BCVA and foveal thickness (FT) at baseline and at months 1, 3, and 6.

RESULTS

Twenty-four of 58 eyes had prior vitrectomy (41%). Statistically significant improvement in BCVA also was seen at 1 month after treatment with a DEX implant and at each subsequent follow-up visit, in either groups (P<0.05). All of the FT reduction outcomes were statistically significant in both groups, with respect to baseline data (P<0.05). There were no statistically significant differences in BCVA and FT between nonvitrectomized and vitrectomized eyes at any time point (P<0.05).

CONCLUSION

In this study, the clinical findings were similar between nonvitrectomized and vitrectomized eyes. Intravitreal treatment with a DEX implant safely reduced DME and improved visual acuity in both groups. No statistically significant differences were found between the 2 groups regarding FT and BCVA.

Treatment of anti-vascular endothelial growth factor-resistant diabetic macular edema with dexamethasone intravitreal implant

PURPOSE

To investigate the efficiency of intravitreal dexamethasone implant in patients with chronic diabetic macular edema nonresponsive to three consecutive monthly intravitreal injections of anti-vascular endothelial growth factor administered previously.

METHODS

Fifteen patients (16 eyes) were included in this 4-month prospective clinical trial. Main observed outcomes were the changes between initial and monthly visits in best-corrected visual acuity, central foveal thickness, and intraocular pressure (IOP). Patients included had central foveal thickness of >225 μm (measured by optical coherence tomography) and were nonresponsive to previously administered 3 consecutive monthly intravitreal injections of 1.25-mg bevacizumab. Administration of intravitreal dexamethasone implant was performed at baseline, and patients were followed-up monthly.

RESULTS

Statistically significant changes from baseline were observed in best-corrected visual acuity (at 2 months), central foveal thickness (at 1, 2, and 3 months), and IOP (at Months 1, 2, and 3) as follows: mean best-corrected visual acuity significantly increased from 0.29 Snellen lines at baseline to 0.39 lines after 2 months (P = 0.0381). At Months 1, 2, and 3, the mean central foveal thickness significantly decreased, from 462 μm at baseline, to 366 μm (P = 0.0343), 346 μm (P = 0.0288), and 355 μm (P = 0.0370), respectively. When compared with baseline IOP of 15.38 mmHg (12-19 mmHg), IOP increased significantly at Months 1, 2, and 3: 18.93 mmHg (range, 16-24 mmHg; P = 0.0003), 19.5 mmHg (range, 16-27 mmHg; P = 0.0003), and 17.5 mmHg (range, 15-21 mmHg; P = 0.0048), respectively.

CONCLUSION

Dexamethasone intravitreal implant may present an alternative option in the treatment of chronic diabetic macular edema nonresponsive to three consecutive monthly bevacizumab injections administered previously. However, IOP measures were only slightly increased. It seems that the effect of dexamethasone may last till 4 months after initial injection.

Kinetics of γ-cyclodextrin nanoparticle suspension eye drops in tear fluid

PURPOSE

We have developed nanoparticle γ-cyclodextrin dexamethasone (DexNP) and dorzolamide (DorzNP) eye drops that provide sustained high drug concentrations on the eye surface. To test these characteristics, we measured dexamethasone and dorzolamide levels in tear fluid in humans following eye drop administration.

METHODS

Concentration of dexamethasone was measured by mass spectrometry. One drop of DexNP was instilled into one eye. Tear fluid was sampled with microcapillary pipettes at seven time-points after drop instillation. Control eyes received Maxidex(®) (dexamethasone). The same procedure was performed for dorzolamide with DorzNP and Trusopt(®) .

RESULTS

Six subjects were included in each group. The peak concentration (μg/ml ± standard deviation) of dexamethasone for DexNP eye drops (636.6 ± 399.1) was up to 19-fold higher than with Maxidex(®) (39.3 ± 18.9) (p < 0.001). At 4 hr, DexNP was still 10 times higher than Maxidex(®) . In addition, DexNP resulted in about 30-fold higher concentration of dissolved dexamethasone in the tear fluid of extended time period allowing more drug to partition into the eye tissue. The overall concentration of dorzolamide was about 50% higher for DorzNP (59.5 ± 76.9) than Trusopt(®) (40.0 ± 76.7) (p < 0.05).

CONCLUSION

The results indicate high and extended concentration of dissolved dexamethasone with DexNP, which can explain the greater and longer lasting effect of dexamethasone in the cyclodextrin nanoparticle drug delivery platform. Dexamethasone seems to fit the cyclodextrin nanoparticle suspension drug delivery platform with longer duration and higher concentrations in tear fluid than available commercial drops, while dorzolamide is less suitable.

Effectiveness of the Dexamethasone Intravitreal Implant for Treatment of Patients with Diabetic Macular Oedema

Diabetic macular oedema (DMO) is a leading cause of vision loss in the working-age population worldwide. Corticosteroid drugs have been demonstrated to inhibit the expression of both the vascular endothelial growth factor (VEGF) gene and other anti-inflammatory mediators, such as prostaglandins. Triamcinolone, fluocinolone and dexamethasone are the main steroids that have been studied for the treatment of macular oedema. Over the last few years, several studies have suggested an important role for dexamethasone in the management of DMO. The dexamethasone intravitreal implant (DEX implant) (Ozurdex®; Allergan, Inc., Irvine, CA) is a novel approach approved by the US Food and Drug Administration (FDA) and by the EU for the intravitreal treatment of macular oedema after branch or central retinal vein occlusion, and for the treatment of non-infectious uveitis affecting the posterior segment of the eye. We reviewed manuscripts that had investigated the pharmacokinetics, efficacy and safety of the DEX implant regarding DMO treatment.

A randomized clinical trial of intravitreal bevacizumab versus intravitreal dexamethasone for diabetic macular edema: the BEVORDEX study

OBJECTIVE

To report the 12-month results of the first head-to-head comparison of a dexamethasone implant (Ozurdex; Allergan, Inc., Irvine, CA) versus bevacizumab (Avastin; Genentech, South San Francisco, CA) for center-involving diabetic macular edema (DME).

DESIGN

Phase 2, prospective, multicenter, randomized, single-masked clinical trial (clinicaltrials.gov identifier NCT01298076).

PARTICIPANTS

We enrolled 88 eyes of 61 patients with center-involving DME.

METHODS

Forty-two eyes were randomized to receive bevacizumab every 4 weeks and 46 eyes were randomized to receive a dexamethasone implant every 16 weeks, both pro re nata. Results were analyzed using linear regression with generalized estimation equation methods to account for between-eye correlation.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of eyes that improved vision by 10 logarithm of minimum angle of resolution letters. Secondary outcomes included mean change in best-corrected visual acuity (BCVA), change in central macular thickness (CMT), injection frequency, and adverse events. Patient-reported outcomes were measured using the Impact of Vision Impairment (IVI) questionnaire.

RESULTS

Improvement in BCVA of 10 or more letters was found in 17 of 42 eyes (40%) treated with bevacizumab compared with 19 of 46 dexamethasone implant-treated eyes (41%; P = 0.83). None of the 42 bevacizumab eyes lost 10 letters or more, whereas 5 of 46 (11%) dexamethasone implant eyes did, mostly because of cataract. Mean CMT decreased by 122 μm for bevacizumab eyes and by 187 μm for dexamethasone implant eyes (P = 0.015). Bevacizumab-treated eyes received a mean of 8.6 injections compared with 2.7 injections for dexamethasone implant eyes. Significant improvement in IVI scores occurred for both treatment groups.

CONCLUSIONS

Dexamethasone implant achieved similar rates of visual acuity improvement compared with bevacizumab for DME, with superior anatomic outcomes and fewer injections. Both treatments were associated with improvement in visual quality-of-life scores. However, more dexamethasone implant-treated eyes lost vision, mainly because of cataract.

Emerging drugs for diabetic macular edema

INTRODUCTION

Diabetic macular edema (DME) is the most common cause of visual impairment due to diabetic retinopathy. The treatment of DME has recently undergone a paradigm shift. Traditionally, photocoagulation was standard treatment, but pharmacologic therapies are becoming increasingly used for this purpose. All currently available drug therapies for DME are either anti-VEGF agents or corticosteroids.

AREAS COVERED

The pathogenesis of DME involves angiogenesis, inflammation and oxidative stress. The scientific rationale to treat DME through the pharmacologic blockade of VEGF and other pro-angiogenic factors is discussed. The fluocinolone insert is approved for the treatment of DME in several European countries, but not in the US at this time. Some medications that are already approved for other retinal diseases, most prominently aflibercept and the dexamethasone delivery system, have recently obtained approval for DME in the US. Other compounds are being studied in earlier-phase clinical trials.

EXPERT OPINION

Pharmacologic treatment of DME will likely become increasingly used, especially for patients with edema involving the fovea. At this time, the two main classes of medication for treatment of DME are anti-VEGF agents and corticosteroids. As we continue to collect clinical trials data, the precise role of individual agents, and the continuing role for photocoagulation, will become more clear.

Evaluation of pain during intravitreal Ozurdex injections vs. intravitreal bevacizumab injections

PURPOSE

The purpose was to evaluate the pain associated with intravitreal Ozurdex injections, and to compare it with that associated with intravitreal bevacizumab injections.

METHODS

The study included 57 eyes of 57 patients who received an intravitreal Ozurdex injection at our institution. Pain was measured by the visual analog scale (VAS). Additional parameters recorded included age, sex, indication for the injection, number of previous Ozurdex injections in the study eye, presence of diabetes mellitus, and lens status. Data were compared with a 2 : 1 sex- and age-matched control group of 114 patients who received intravitreal bevacizumab injections.

RESULTS

Indications for injection included diabetic macular edema (40.4%) and macular edema secondary to central and branch retinal vein occlusion (28% and 31.6%, respectively). Pain scores on the VAS ranged from 0 to 90, with a mean of 20.8±20.3. There was no significant difference in pain between Ozurdex and bevacizumab injections. Pseudophakia was correlated with increased pain in Ozurdex injections.

CONCLUSIONS

This is the first series evaluating the pain associated with intravitreal Ozurdex injections. Despite a larger needle gauge and tunneled injection technique, intravitreal injection of Ozurdex is not associated with increased pain compared with bevacizumab. This finding may be a potential advantage for Ozurdex, and may serve to improve patient compliance with future long-term treatment protocols.

Intravitreal dexamethasone implant in patients with persistent macular edema of variable etiologies

PURPOSE

To examine the effect of an intravitreal dexamethasone drug delivery system (DEX-DDS) in the treatment of persistent cystoid macular edema (CME) of different etiologies.

METHODS

Thirty-seven eyes with persistent CME were treated with DEX-DDS and analyzed for changes in best-corrected visual acuity (BCVA) and optical coherence tomography. Eyes were categorized into three groups: diabetic macular edema (DME, n = 14), vein occlusion (n = 15) and uveitis (n = 7).

RESULTS

The mean follow-up was 22 ± 6.9 weeks. BCVA improved from 0.62 ± 0.38 to 0.35 ± 0.29 logMAR (p < 0.0001). Central macular thickness decreased by 184 ± 246 µm from baseline (p < 0.0001). In eyes where CME resolved and recurred, the average CME-free period was 11 weeks. The uveitis group showed faster CME resolution (2 weeks) and a longer CME-free period (20 weeks). Similar efficacy was shown for repeat DEX-DDS injections. The safety profile was good.

CONCLUSION

DEX-DDS is beneficial in the treatment of persistent CME. In cases of uveitis, CME resolution is rapid, resulting in the longest effect duration, when compared with other CME etiologies.

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

INTRODUCTION

Diabetic macular edema (DME) can be treated with intravitreal glucocorticoids, particularly triamcinolone acetonide, dexamethasone (DEX), and fluocinolone acetonide (FA).

AREAS COVERED

The pathophysiology of DME includes multiple growth factors such as VEGF and also inflammatory mediators. Glucocorticoids act on DME through multiple pathways, and current research into their efficacy, safety, and therapeutic potential when administered intravitreally is discussed.

CONCLUSION

The intravitreal route of administration minimizes systemic side effects of glucocorticoids. Furthermore, sustained-release low-dose delivery via the DEX implant or the FA implant will limit frequent intravitreal injection and possibly some cost associated with intravitreal anti-VEGF therapy. In addition, the durable action of these treatments facilitates combination therapy. Patients can receive these implants as foundational therapy, and then receive additional treatment with laser or intravitreal anti-VEGF agents as combination therapy, which may conceivably provide some synergistic benefit. While the FA implant lasts much longer than the DEX implant, potentially decreasing the visit and treatment burden on patients and their families, the FA implant appears to have a greater risk of inducing ocular hypertension and cataract. However, these modalities have not been directly compared in a clinical trial and there is insufficient evidence to draw more elaborate conclusions.

Evolving strategies in the management of diabetic retinopathy

Diabetic retinopathy (DR), the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Tight glycemic and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Focal/grid photocoagulation and panretinal photocoagulation are standard treatments for both DME and PDR, respectively. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with DME. Currently, most experts consider combination focal/grid laser therapy and pharmacotherapy with intravitreal antivascular endothelial growth factor agents in patients with center-involving DME. Combination therapy reduces the frequency of injections needed to control edema. Vitrectomy with removal of the posterior hyaloid seems to be effective in eyes with persistent diffuse DME, particularly in eyes with associated vitreomacular traction. Emerging therapies include fenofibrate, ruboxistaurin, renin-angiotensin system blockers, peroxisome proliferator-activated receptor gamma agonists, pharmacologic vitreolysis, and islet cell transplantation.

The effect of an intravitreal dexamethasone implant for cystoid macular edema in retinitis pigmentosa: a case report and literature review

Intravitreal injection of a dexamethasone implant was used to treat a 24-year-old patient with retinitis pigmentosa (RP) who developed cystoid macular edema (CME) in both eyes that was refractory to oral acetazolamide and intravitreal bevacizumab treatment. After injection, best corrected visual acuity (BCVA) improved and central macular thickness decreased, but CME recurred in both eyes 6 months later. Although a second intravitreal dexamethasone implant injection resolved the CME and improved the BCVA, CME recurred in both eyes 6 months later. The intravitreal dexamethasone implant may be useful for CME in patients with RP, but its efficacy seems to be limited over time.

Dexamethasone intravitreal implant for treatment of uveitic persistent cystoid macular edema in vitrectomized patients

PURPOSE

To evaluate the safety and efficacy of Ozurdex (dexamethasone intravitreal implant) 0.7 mg in the treatment of uveitic macular edema in vitrectomized eyes.

METHODS

Data from 13 patients (17 eyes) with persistent uveitic cystoid macular edema and a history of pars plana vitrectomy in the study eyes that were treated with intravitreal injection of 0.7-mg dexamethasone implant were reviewed retrospectively. Main outcome measures were changes in central retinal thickness measured by optical coherence tomography and changes in best-corrected visual acuity.

RESULTS

The median age of patients was 61 years (range, 19-81 years). The median duration of uveitic macular edema was 12 months (range, 2-72 months). The mean baseline central retinal thickness (95% confidence interval) was 461.6 μm (403.8-519.4), decreased to 277.2 μm (244.6-309.8) at 4 weeks (P < 0.01), remained low at 349.9 μm (281.8-418.0) at 3 months (P = 0.01), and then reached 394.1 μm (328.3-459.8) at 6 months (P = 0.14). After 3 months, there was a median improvement of 2 lines of best-corrected visual acuity, with 52.9% of eyes gaining 2 lines or more (P < 0.01). At 6 months, there were 5 eyes that maintained the 2 lines gain and none had lost >1 line from baseline (P = 0.03). In 8 eyes (47.1%), reinjection of the implant was performed at a mean of 6.5 months. Ocular hypertension (47.1%), hypotony (11.8%), anterior chamber displacement of the implant (5.9%), and glaucoma, which required filtration surgery (5.9%), were the most common adverse events. Mean follow-up was 9.6 months (range, 6-17 months).

CONCLUSION

In this small case series of eyes with limited follow-up, treatment with dexamethasone intravitreal implant injection for uveitic macular edema in vitrectomized eyes was associated with favorable visual outcomes and had an acceptable safety profile.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Dexamethasone intravitreal implant for treatment of patients with persistent diabetic macular edema

PURPOSE

To report the 6-month anatomical and best-corrected visual acuity (BCVA) response after primary intravitreal dexamethasone implantation (Ozurdex®) in patients with refractory diabetic macular edema (DME).

METHODS

Retrospective review of the medical records of 58 patients with decreased visual acuity, due to refractory DME, who underwent a single injection of Ozurdex between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain.

RESULTS

At baseline, the mean foveal thickness (FT) was 543.24 ± 156.51 μm. Mean (±SD) values of FT did decrease to 346.82 ± 123.74 μm at month 1 and 341.12 ± 129.64 μm at month 3. Data on the 6-month follow-up showed a mild increase to 420.16 ± 152.15 μm. All of the FT reduction outcomes were statistically significant, with respect to baseline data (p = 0.0001). The baseline BCVA data was 0.66 ± 0.36 logarithm of the minimum angle of resolution (logMAR). The mean BCVA improved to 0.52 ± 0.32 logMAR (p = 0.0001) and 0.44 ± 0.27 logMAR (p = 0.0001) after 1 and 3 months, respectively. At the last visit (6-month follow-up), the mean BCVA increased to 0.51 ± 0.31 logMAR (p = 0.0001).

CONCLUSIONS

In this study, intravitreal treatment with a dexamethasone implant safely reduced DME and improved visual acuity in a difficult-to-treat patient population with long-standing refractory DME.

Importance of 3-D image reconstruction of spectral-domain OCT on outcome of grid laser photocoagulation for diffuse diabetic macular edema

AIM

To present the outcome of modified grid laser photocoagulation (GLP) in diffuse diabetic macular edema (DDME) in eyes without extrafoveal and/or vitreofoveal traction.

METHODS

Inclusion criteria for the retrospective study were DDME eyes of patients with type II diabetes mellitus that had ≥4 months of follow-up following GLP. Only one eye per patient was analyzed. Using 3-D spectral-domain optical coherence tomography (3-D SD-OCT), eyes that had either extrafoveal or vitreofoveal traction, or had been previously treated by an intravitreal medication(s) were excluded. Treated DDME eyes were divided into 4 groups: A) "Classic" DDME that involved the central macula; B) edema did not involve the macular center; C) eyes associated with central epiretinal membrane (ERM); D) DDME that was associated with macular capillary dropout ≥2 disc-diameter (DD).

RESULTS

GLP outcome in 35 DDME eyes after 4-24 (mean, 13.1±6.9) months was as follows: Group A) 18 eyes with "classic" DDME. Following one or 2 (mean, 1.2) GLP treatments, best-corrected visual acuity (BCVA) improved by 1-2 Snellen lines in 44.4% (8/18) of eyes, and worsened by 1 line in 11.1% (2/18). Central macular thickness (CMT) improved by 7%-49% (mean, 26.6%) in 77.8% (14/18) of eyes. Causes of CMT worsening (n=4) were commonly explainable, predominantly (n=3) associated with emergence of extrafoveal traction, 5-9 months post-GLP. Group B) GLP(s) in DDME that did not involve the macular center (n=6) resulted in improved BCVA by 1-2 lines in 2 eyes. However, the central macula became involved in the edema process after the GLP in 3 (50%) eyes, associated with an emergence of extrafoveal traction in one of these eyes 4 months following the GLP. Group C) GLP failed in all 5 eyes associated with central ERM. Group D) GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout ≥2DD.

CONCLUSION

Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s) during mid-term follow-up, unless complicated pre-GLP or post-GLP by vitreoretinal interface abnormalities, often extrafoveal traction or ERM, or by capillary dropout ≥2DD. Prospective studies with larger cohorts are required.

Ozurdex (a slow-release dexamethasone implant) in proliferative vitreoretinopathy: study protocol for a randomised controlled trial

Background

Proliferative vitreoretinopathy (PVR) is the commonest cause of late anatomical failure in rhegmatogenous retinal detachment. Visual and anatomical outcomes remain poor despite advances in vitreoretinal surgical techniques with reported primary failure rates of up to nearly 50%. Numerous adjunctive medications have been evaluated in clinical trials with no agent gaining widespread acceptance and use.

This study was designed to investigate the benefits of using a slow-release dexamethasone implant delivered intra-operatively in patients undergoing vitrectomy surgery for retinal detachment with established PVR.

Methods/design

For the study, 140 patients requiring vitrectomy surgery with silicone oil for retinal detachment with established PVR will be randomised to receive either standard treatment or study treatment in a 1:1 treatment allocation ratio. Both groups will receive the standard surgical treatment appropriate for their eye condition and routine peri-operative treatment and care, differing only in the addition of the supplementary adjunctive agent in the treatment group. The investigated primary outcome measure is stable retinal reattachment with removal of silicone oil without additional vitreoretinal surgical intervention at 6 months.

Discussion

This is the first randomised controlled clinical trial to investigate the use of an adjunctive slow-release dexamethasone implant in patients undergoing vitrectomy surgery for retinal detachments with proliferative vitreoretinopathy.

Trial registration

EudraCT No: 2011-004498-96.

Anatomic and pharmacokinetic properties of intravitreal bevacizumab and ranibizumab after vitrectomy and lensectomy

PURPOSE

To determine the anatomic characteristics and pharmacokinetic properties of intravitreally placed bevacizumab and ranibizumab after pars plana lensectomy or pars plana vitrectomy and to compare these with nonoperated control eyes in a rabbit model.

METHODS

Three groups of six Dutch-belted rabbits each underwent pars plana vitrectomy, pars plana lensectomy, or served as nonsurgical controls. Twelve days after surgery, 3 rabbits from each group underwent intravitreal injection in one eye with 1.25 mg/0.05 mL I-124-bevacizumab or 0.5 mg/0.05 mL I-124-ranibizumab. Serial imaging with integrated positron emission and computed tomography (PET/CT) were obtained on Days 0, 2, 5, 7, 14, 21, 28, and 35. Measured radioactivity emission in becquerels/milliliter was used to calculate the half-lives for each agent.

RESULTS

The intravitreally placed radiolabeled agents were contained within the vitreous cavity for the duration of the study. The average clearance half-lives with standard error for bevacizumab and ranibizumab after correction for radioactive decay were, respectively, 4.22 ± 0.07 days and 2.81 ± 0.05 days in unoperated eyes, 2.30 ± 0.09 days (P < 0.0001) and 2.13 ± 0.05 days (P < 0.0001) after vitrectomy, and 2.08 ± 0.07 days (P = 0.0001) and 1.79 ± 0.05 days (P < 0.0001) after lensectomy.

CONCLUSION

Intravitreal retention was longer for bevacizumab than ranibizumab within all study groups and was significantly reduced after vitrectomy and lensectomy for both agents. Consideration for more frequent intravitreal anti-vascular endothelial growth factor dosing regimens may be made for patients whose treated eyes have undergone previous vitrectomy or who are aphakic.

The evolving treatment options for diabetic macular edema

Diabetic retinopathy (DR) is the leading cause of vision loss in working-age adults, and diabetic macular edema (DME) is the most common cause of visual impairment in individuals with DR. This review focuses on the pathophysiology, previous treatment paradigms, and emerging treatment options in the management of DME.

Microvascular complications and diabetic retinopathy: recent advances and future implications

Retinal microvascular alterations have been observed during diabetic retinopathy (DR) due to the retinal susceptibility towards subtle pathological alterations. Therefore, retinal microvascular pathology is essential to understand the nature of retinal degenerations during DR. In this review, the role of retinal microvasculature complications during progression of DR, along with recent efforts to normalize such alterations for better therapeutic outcome, will be underlined. In addition, current therapeutics and future directions for advancement of standard treatment for DR patients will be discussed.

Intravitreal Corticosteroids in the Management of Diabetic Macular Edema

Diabetic macular edema (DME) remains an important worldwide cause of visual loss. Corticosteroids have a role in the treatment of some patients with advanced or recurrent DME. The best studied steroids for this indication are triamcinolone acetonide, dexamethasone, and fluocinolone acetonide. All steroids are associated with risks of cataract and intraocular pressure elevation. In addition, intravitreal injection of any medication is associated with risks of infectious endophthalmitis, which has led to the investigation of various extended-release steroid implants. At this time, no steroid is approved by the United States Food and Drug Administration (FDA) for the treatment of DME.

Dexamethasone implant anterior chamber migration: risk factors, complications, and management strategies

OBJECTIVE

To describe the risk factors, clinical course, and complications of migration of a dexamethasone (DEX) intravitreal implant (OZURDEX; Allergan, Inc., Irvine, CA) into the anterior chamber and subsequent management strategies.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Fifteen patients had 18 episodes of migration of the DEX implant into the anterior chamber.

METHODS

The medical records of 15 patients with spontaneous migration of a DEX implant were retrospectively reviewed.

MAIN OUTCOME MEASURES

Migration of the DEX implant into the anterior chamber.

RESULTS

Migration of a DEX intravitreal implant into the anterior chamber occurred in 6 patients who were aphakic, 4 patients with an anterior chamber intraocular lens, 2 patients with a scleral-fixated posterior chamber intraocular lens (PCIOL), 2 patients with a PCIOL, and 1 patient with an iris-fixated PCIOL. All 15 patients had prior pars plana vitrectomy, and 14 patients (93%) had no lens capsule. The average interval from DEX implant injection to detection of the implant migration into the anterior chamber was 13 days (range, 5-44 days). In 14 patients, corneal edema developed. Among those eyes undergoing surgical removal of the implant, earlier intervention reduced the likelihood of permanent corneal edema (0.5 days [from diagnosis of migration to surgical removal of the implant] vs. 5.5 days; P = 0.04). Aspiration was necessary to remove the implant in 6 patients. Among the 14 patients with corneal edema, the corneal edema did not resolve in 10 patients (71%), 6 (43%) of whom required corneal transplantation.

CONCLUSIONS

Absence of lens capsule and prior vitrectomy are risk factors for migration of the DEX implant into the anterior chamber. Early removal of the implant may be necessary to minimize the risk of chronic corneal edema.

Preliminary results of an intravitreal dexamethasone implant (Ozurdex®) in patients with persistent diabetic macular edema

BACKGROUND

To evaluate the efficacy and safety of an intravitreal dexamethasone implant (Ozurdex®; Allergan Inc, Irvine, CA, USA) in patients with persistent diabetic macular edema (DME) over a 6-month follow-up period.

METHODS

Seventeen patients (20 eyes) affected by DME were selected. The mean age was 67 + 8 years, and the mean duration of DME was 46.3 + 18.6 months. The eligibility criteria were: age ≥ 18, a best-corrected visual acuity between 5 and 40 letters, and macular edema with a thickness of ≥275 μm. Thirteen patients had also previously been treated with anti-vascular endothelial growth factor medication.

RESULTS

The mean ETDRS (Early Treatment Diabetic Retinopathy Study) value went from 18.80 + 11.06 (T0) to 26.15 + 11.03 (P = 0.04), 28.15 + 10.29 (P = 0.0087), 25.95 + 10.74 (P = 0.045), 21.25 + 11.46 (P = 0.5) in month 1, 3, 4, and 6, respectively. The mean logMAR (logarithm of the minimum angle of resolution) value went from 0.67 + 0.23 (at T0) to 0.525 + 0.190 (P = 0.03), 0.53 + 0.20 (P = 0.034), and 0.56 + 0.22 (P = 0.12) in month 1, 3, and 4, respectively, to finally reach 0.67 + 0.23 in month 6. The mean central macular thickness value improved from 518.80 + 224.75 μm (at T0) to 412.75 + 176.23 μm, 292.0 + 140.8 μm (P < 0.0001), and 346.95 + 135.70 (P = 0.0018) on day 3 and in month 1 and 3, respectively, to then increase to 476.55 + 163.14 μm (P = 0.45) and 494.25 + 182.70 μm (P = 0.67) in month 4 and 6.

CONCLUSION

The slow-release intravitreal dexamethasone implant, Ozurdex, produced significant improvements in best-corrected visual acuity and central macular thickness from the third day of implant in DME sufferers, and this improvement was sustained until the third month.

Evolving strategies in the management of diabetic macular edema: clinical trials and current management

Diabetic macular edema (DME) is the leading cause of vision loss in the working-age population in developed countries. Management has traditionally consisted of focal/grid macular laser, according to the guidelines established by the Early Treatment of Diabetic Retinopathy Study. More recent prospective clinical trials examining the effect of intravitreal ranibizumab in the treatment of DME--most notably, READ-2, RESOLVE, RESTORE, RISE/RIDE, and DRCR.net protocol I--have demonstrated improved visual outcomes with pharmacologic targeting of vascular endothelial growth factor. Similar treatment benefits have also been noted in clinical trials evaluating intravitreal bevacizumab and aflibercept (Bolt and da Vinci, respectively). Intravitreal steroids, particularly in refractory cases, continue to have a limited role in the management of DME. In patients with symptomatic visual loss, the treatment paradigm for DME has shifted toward intravitreal pharmacotherapeutics, principally anti-vascular endothelial growth factor therapy, and this review examines the clinical trials leading to this change.

Dexamethasone intravitreal implant in combination with laser photocoagulation for the treatment of diffuse diabetic macular edema

PURPOSE

To evaluate Ozurdex (dexamethasone intravitreal implant [DEX implant]; Allergan, Inc, Irvine, CA) 0.7 mg combined with laser photocoagulation compared with laser alone for treatment of diffuse diabetic macular edema (DME).

DESIGN

Randomized, controlled, multicenter, double-masked, parallel-group, 12-month trial.

PARTICIPANTS

Two hundred fifty-three patients with retinal thickening and impaired vision resulting from diffuse DME in at least 1 eye (the study eye) were enrolled.

INTERVENTION

Patients were randomized to treatment in the study eye with DEX implant at baseline plus laser at month 1 (combination treatment; n = 126) or sham implant at baseline and laser at month 1 (laser alone; n = 127) and could receive up to 3 additional laser treatments and 1 additional DEX implant or sham treatment as needed.

MAIN OUTCOME MEASURES

The primary efficacy variable was the percentage of patients who had a 10-letter or more improvement in best-corrected visual acuity (BCVA) from baseline at month 12. Other key efficacy variables included the change in BCVA from baseline and the area of vessel leakage evaluated with fluorescein angiography. Safety variables included adverse events and intraocular pressure (IOP).

RESULTS

The percentage of patients who gained 10 letters or more in BCVA at month 12 did not differ between treatment groups, but the percentage of patients was significantly greater in the combination group at month 1 (P<0.001) and month 9 (P = 0.007). In patients with angiographically verified diffuse DME, the mean improvement in BCVA was significantly greater with DEX implant plus laser treatment than with laser treatment alone (up to 7.9 vs. 2.3 letters) at all time points through month 9 (P ≤ 0.013). Decreases in the area of diffuse vascular leakage measured angiographically were significantly larger with DEX implant plus laser treatment through month 12 (P ≤ 0.041). Increased IOP was more common with combination treatment. No surgeries for elevated IOP were required.

CONCLUSIONS

There was no significant between-group difference at month 12. However, significantly greater improvement in BCVA, as demonstrated by changes from baseline at various time points up to 9 months and across time based on the area under the curve analysis, occurred in patients with diffuse DME treated with DEX implant plus laser than in patients treated with laser alone.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Corticosteroid intravitreal implants vs. ranibizumab for the treatment of vitreoretinal disease

PURPOSE OF REVIEW

Three long-acting corticosteroid implants are now available for the treatment of retinal disease, offering control of macular edema and inflammation for between 6 months and up to 3 years. This review evaluates their efficacy and side-effect profile in comparison with the antivascular endothelial growth factor agent ranibizumab in diabetic macular edema, retinal vein occlusion, pseudophakic macular edema, and uveitis.

RECENT FINDINGS

Trials of ranibizumab in diabetic macular edema have demonstrated excellent efficacy without serious safety concerns to date. Fluocinolone acetonide implants can be considered, but have a high risk of cataract and sequelae from intraocular pressure rise. In retinal vein occlusion, both ranibizumab and Ozurdex have been shown to be effective, although their relative efficacy has not been determined in head-to-head clinical trials. In pseudophakic and uveitic macular edema, steroid implants are probably the first choice therapy, although there is evidence that ranibizumab is effective. For choroidal neovascularization secondary to inflammatory disease, ranibizumab is indicated, whereas Retisert has been shown to reduce the risk of uveitis relapse.

SUMMARY

In diabetic macular edema, ranibizumab has shown greater efficacy with fewer side-effects than steroid implants. Both ranibizumab and steroid implants can be considered in retinal vein occlusion, but trials are awaited to determine their relative efficacy.

Pharmacologic and clinical profile of dexamethasone intravitreal implant

The challenge in the treatment of chronic retinal diseases is to deliver effective therapy to the target tissues in the back of the eye while limiting drug exposure in nontarget tissues. Intravitreal placement provides the most targeted drug delivery, but repeated penetration of the globe to deliver intravitreal therapy can pose safety risks. A more effective strategy for the treatment of chronic retinal diseases would be to combine intravitreal placement with sustained drug delivery. The dexamethasone intravitreal (DEX) implant is a biodegradable sustained-release intravitreal drug delivery system that is approved for the treatment of macular edema following branch or central retinal vein occlusion and for noninfectious uveitis affecting the posterior segment of the eye. A single DEX implant has been shown to provide clinical benefits for up to 6 months in eyes with retinal vein occlusion or intermediate or posterior uveitis.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Liposomes and nanotechnology in drug development: focus on ocular targets

Poor drug delivery to lesions in patients’ eyes is a major obstacle to the treatment of ocular diseases. The accessibility of these areas to drugs is highly restricted by the presence of barriers, including the corneal barrier, aqueous barrier, and the inner and outer blood–retinal barriers. In particular, the posterior segment is difficult to reach for drugs because of its structural peculiarities. This review discusses various barriers to drug delivery and provides comprehensive information for designing nanoparticle-mediated drug delivery systems for the treatment of ocular diseases. Nanoparticles can be designed to improve penetration, controlled release, and drug targeting. As highlighted in this review, the therapeutic efficacy of drugs in ocular diseases has been reported to be enhanced by the use of nanoparticles such as liposomes, micro/nanospheres, microemulsions, and dendrimers. Our recent data show that intravitreal injection of targeted liposomes encapsulating an angiogenesis inhibitor caused significantly greater suppression of choroidal neovascularization than did the injection of free drug. Recent progress in ocular drug delivery systems research has provided new insights into drug development, and the use of nanoparticles for drug delivery is thus a promising approach for advanced therapy of ocular diseases.

Pathophysiology and treatment of diabetic retinopathy

In the past years, the management of diabetic retinopathy (DR) relied primarily on a good systemic control of diabetes mellitus, and as soon as the severity of the vascular lesions required further treatment, laser photocoagulation or vitreoretinal surgery was done to the patient. Currently, even if the intensive metabolic control is still mandatory, a variety of different clinical strategies could be offered to the patient. The recent advances in understanding the complex pathophysiology of DR allowed the physician to identify many cell types involved in the pathogenesis of DR and thus to develop new treatment approaches. Vasoactive and proinflammatory molecules, such as vascular endothelial growth factor (VEGF), play a key role in this multifactorial disease. Current properly designed trials, evaluating agents targeting VEGF or other mediators, showed benefits in the management of DR, especially when metabolic control is lacking. Other agents, directing to the processes of vasopermeability and angiogenesis, are under investigations, giving more hope in the future management of this still sight-threatening disease.

A preliminary evaluation of dexamethasone palmitate emulsion: a novel intravitreal sustained delivery of corticosteroid for treatment of macular edema

PURPOSE

Dexamethasone palmitate (DXP) is a lipophilic prodrug of dexamethasone (DXM), a potent corticosteroid used to treat a variety of ophthalmic diseases. The aim of the study was to characterize the sustained release capacity (in rabbit), efficacy (in rat and rabbit), and safety (in rabbit, cat, and minipig) of intravitreal (IVT) DXP emulsions in preclinical models.

METHODS

Oil-in-water emulsions of DXP were administered by IVT injections in rats, rabbits, cats, or minipigs. Efficacy was assessed in rabbits by the inhibition of VEGF-induced vascular leakage and in rats by inhibition of laser-induced choroidal neovascularization. Concentrations of DXP and DXM in aqueous humor, vitreous, retina, choroid, and blood were determined to characterize the ocular and systemic pharmacokinetic (PK) profile. Complete ophthalmic examinations (indirect ophthalmoscopy, slit-lamp biomacroscopy, electroretinography, tonometry) were performed to assess the ocular safety of IVT DXP doses up to 2,600 μg in minipig, followed by histopathologic examinations. A validated feline model of DXM-induced elevated intraocular pressure (IOP) was used to assess the ocular hypertensive impact (i.e., the safety) of an IVT injection of DXP emulsion.

RESULTS

Rat and rabbit efficacy data demonstrated that IVT injections of DXP emulsions were effective. Rabbit PK data demonstrated that following a single 1,280 μg IVT injection resulted in sustained DXM levels in the retina and choroid (1,179.6 and 577.7 ng/g with a half-life of 189 and 103 days, respectively) sufficient to inhibit VEGF-induced vascular hyper-permeability for up to 9 months. No adverse ocular findings were observed in the rabbit at the 1,280 μg DXP dose. Plasma levels of DXP and DXM were close to the lower limit of quantification (0.5 ng/mL). In minipigs, no systemic effects were observed at a dose up to 2,600 μg DXP. In steroid responsive cats, IVT DXP emulsions increased IOP to a lesser extent than triamcinolone acetonide with a more rapid return to basal levels and no evidence of cataract formation.

CONCLUSIONS

IVT injections of DXP emulsions were well tolerated and shown to be efficacious for the sustained release of the drug, with the potential to control vascular leakage up to 9 months following a single IVT injection. These data suggest that IVT injections of DXP emulsions could be a safe and effective alternative IVT drug delivery vehicle for corticosteroid to treat back of the eye diseases complicated by macular edema.

Think global--act local: intravitreal drug delivery systems in chronic noninfectious uveitis

The eye is probably the most attractive site of the body for treatment using locally delivered therapeutic agents. An ideal indication for such an approach is noninfectious posterior uveitis. Since intraocular structures of the posterior segment are difficult to reach and are otherwise accessible only by systemic treatment, current interest is focused on the pros and cons of intravitreal drug delivery. Because of its chronic and recurrent nature, the long-term release of anti-inflammatory agents is a major treatment goal. Intravitreal injections, intravitreal implants and biodegradable devices are the most commonly used and approved approaches to deliver various agents to the vitreous. Because of their broad and potent effects, corticosteroids (CS) have been the first-line candidates for intraocular delivery. An increasing spectrum of CS preparations including nondegradable and biodegradable devices is currently available. Since repeated and long-term applications bear the risk of steroid-related complications such as increased intraocular pressure and cataract, alternative agents are currently being tested. Intravitreal injection of methotrexate, anti-VEGF (vascular endothelial growth factor), anti-TNFα (tumor necrosis factor α) and sirolimus have also been applied in patients with conflicting results. Intravitreal treatment has significantly reduced the incidence of adverse effects compared to systemic application, but due to greater ocular side effects there are still some limitations.

Intravitreal autologous plasmin as a therapeutic modality for diffuse diabetic macular edema

OBJECTIVES

To evaluate the outcome of vitreolysis using intravitreal autologous plasmin (IAP) injection as a sole therapeutic modality for patients with diffuse diabetic macular edema in comparison to triamcinolone acetonide (TA).

PATIENTS AND METHODS

The study included 50 diabetic patients, 18 males and 32 females, with a mean age of 66.4 ± 7.8 years and a mean duration of diabetes of 14 ± 2.4 years. All patients underwent full ophthalmologic examination and were allocated randomly into two groups: the TA group received 4 mg TA and the IAP group received 0.2 mL freshly home-prepared autologous plasmin. Outcome measures included determination of central macular thickness (CMT), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) at 1, 3, and 6 months.

RESULTS

Both TA and plasmin induced significant decrease of CMT compared to baseline thickness with nonsignificant difference between both groups. The extent of decrease of CMT reached a peak at 1 month after injection and then started to decline until the sixth month, but was significantly thinner when compared to baseline thickness. However, the extent of deterioration was less evident with plasmin as the difference between follow-up measures at 3 and 6 months were nonsignificant compared to the 1-month measure and to each other. BCVA was significantly improved compared to baseline BCVA with a nonsignificant difference between both groups at 1 and 3 months, but at 6 months, mean BCVA significantly deteriorated in TA group compared to that recorded at 3 months, but not in the IAP group. At 3 and 6 months after injection, IOP was significantly lower in both groups compared to IOP at 1 month despite being significantly higher in the TA group, but IOP was nonsignificantly lower in the IAP group compared to baseline. Moreover, mean IOP estimated at 3 and 6 months was significantly higher in the TA group compared to the IAP group.

CONCLUSION

Vitreolysis using IAP injection provided effective diminution of CMT with improvement of BCVA and this effect was longer lasting and safer than intravitreal injection of TA without concomitant increase of IOP.

Long-term evaluation of patients treated with dexamethasone intravitreal implant for macular edema due to retinal vein occlusion

PURPOSE

To evaluate the long-term visual prognosis and complications of patients who received intravitreal Ozurdex injections for the treatment of macular edema (ME) due to retinal vein occlusion (RVO).

METHODS

A total of 17 patients who received Ozurdex injections in our institution as part of the GENEVA study were recalled for examination. Recorded parameters included final visual acuity (VA), final retinal thickness by optical coherence tomography, persistence of ME, and the occurrence of any complications.

RESULTS

Mean follow-up time was 50.5 months. Patients with branch RVO (BRVO) had a more favorable prognosis than central RVO (CRVO), and their mean VA had improved significantly, whereas the mean VA for the patients with CRVO did not improve significantly. Retinal thickness had reduced significantly in the whole group and in each subgroup separately. Complications included 10 patients with cataract progression, 1 with elevated intraocular pressure, and 1 with neovascularization and vitreous hemorrhage.

CONCLUSIONS

This is the first reported long-term evaluation of patients treated with Ozurdex. Our results indicate that it has favorable long-term safety profile, and may have a beneficial effect on the visual prognosis in BRVO even in the absence of continuous treatment. Further research is required to establish the optimal retreatment schedule for Ozurdex.