Ocular pharmacokinetics of fluocinolone acetonide after Retisert intravitreal implantation in rabbits over a 1-year period

Trans-corneal drug delivery strategies in the treatment of ocular diseases

The cornea is a remarkable tissue that possesses specialized structures designed to safeguard the eye against foreign objects. However, its unique properties also make it challenging to deliver drugs in a non-invasive manner. This review highlights recent advancements in achieving highly efficient drug transport across the cornea, focusing on nanomaterials. We have classified these strategies into three main categories based on their mechanisms and have analyzed their success and limitations in a systematic manner. The purpose of this review is to examine potential general principles that could improve drug penetration through the cornea and other natural barriers in the eye. We hope it will inspire the development of more effective drug delivery systems that can better treat ocular diseases.

Eudragit® L100/Polyvinyl Alcohol Nanoparticles Impregnated Mucoadhesive Films as Ocular Inserts for Controlled Delivery of Erythromycin: Development, Characterization and In Vivo Evaluation

The fast elimination of drugs from the cornea is one of many challenges associated with the topical administration of conventional dosage forms. The present manuscript aimed to prepare modified-release inserts containing erythromycin (ERY) to enhance drug delivery and address the aforementioned limitation. Film formulations were developed using Eudragit^® L100 (EUD) and Polyvinyl Alcohol (PVA) polymers. ERY-loaded EUD-based nanoparticles were developed by the colloidal dispersion method using PVA as the emulsifier. The film-casting method was applied to form the mucoadhesive films using sodium alginate, gelatin, cyclodextrin-α, and β as polymeric film matrices. Different physicochemical properties of the optimized formulations and in vitro release profiles were evaluated. The in vivo evaluation was performed by collecting tear samples of rabbits using a novel, non-invasive method following the administration of inserts in the cul-de-sac. The ERY amount was assayed using a microbiological assay. The developed films showed prolonged in vitro and in vivo release profiles over five to six days; they had suitable physicochemical properties and a tensile strength of 2–3 MPa. All formulations exhibited antibacterial efficacy against E. coli and S. aureus with more than 20 mm diameter of inhibited growth zones. None of the formulations caused irritation to the rabbit’s eye. The inserts showed promising pharmacokinetics with AUC_0–120 of 30,000–36,000 µg·h/mL, a C_max of more than 1800 µg/mL at 4 h, and maintained drug concentration over the threshold of 5 µg/mL during the following 120 h of study. Nanoparticle-containing, mucoadhesive films could be fabricated as ocular inserts and can prolong the topical ocular delivery of ERY.

Long-acting ocular drug delivery technologies with clinical precedent

INTRODUCTION

Ocular long-acting injectables and implants (LAIIs) deliver drug at a controlled release rate over weeks to years. A reduced dose frequency eases the treatment burden on patients, minimizes the potential for treatment-related adverse effects, and improves treatment adherence and persistence.

AREAS COVERED

This review provides a comprehensive landscape of ocular LAII drug delivery technologies with clinical precedent, including eight commercial products and 27 clinical programs. Analysis of this landscape, and the specific technologies with the greatest precedent, provides instructive lessons for researchers interested in this space and insights into the direction of the field.

EXPERT OPINION

Further technological advancement is required to create biodegradable LAIIs with extended release durations and LAIIs that are compatible with a broader array of therapeutic modalities. In the future, ocular LAII innovations can be applied to diseases with limited treatment options, prophylactic treatment at earlier stages of disease, and cost-effective treatment of ocular diseases in global health settings.

Polymer based sustained drug delivery to the ocular posterior segment: barriers and future opportunities for the treatment of neovascular pathologies

There is an increasing momentum in research and pharmaceutical industry communities to design sustained, non-invasive delivery systems to treat chronic neovascular ocular diseases that affect the posterior segment of the eye including age-related macular degeneration and diabetic retinopathy. Current treatments include VEGF blockers, which have revolutionized the standard of care for patients, but their maximum therapeutic benefit is hampered by the need for recurrent and invasive administration procedures. Currently approved delivery systems intended to address these limitations exploit polymer technology to regulate drug release in a sustained manner. Here, we critically review sustained drug delivery approaches for the treatment of chronic neovascular diseases affecting the ocular posterior segment, with a special emphasis on novel and polymeric technologies spanning the spectrum of preclinical and clinical investigation, and those approved for treatment. The mechanism by which each formulation imparts sustained release, the impact of formulation characteristics on release and foreign body reaction, and special considerations related to the translation of these systems are discussed.

Evaluating the Safety, Efficacy and Patient Acceptability of Intravitreal Fluocinolone Acetonide (0.2mcg/Day) Implant in the Treatment of Non-Infectious Uveitis Affecting the Posterior Segment

Long-acting, slow-release injectable fluocinolone intravitreal implants have been approved for the treatment of non-infectious uveitis affecting the posterior segment. We summarise the development of intravitreal fluocinolone implants and discuss the technology including pharmacokinetics. We conducted a systematic review of evidence for the efficacy, safety and patient acceptability of fluocinolone 0.18 mg and 0.19 mg injectable implants. We summarise evidence from the pivotal phase 3 studies that lead to the approval of these implants and evaluate real-world including disease-specific evidence. Safety including injection-related events and long-term adverse events is presented.

Uveitis Therapy: The Corticosteroid Options

Uveitis is characterized by intraocular inflammation involving the uveal tract; its etiologies generally fall into two broad categories: autoimmune/inflammatory or infectious. Corticosteroids  are a powerful and important class of medications ubiquitous in the treatment of uveitis. They may be given systemically or locally, in the form of topical drops, periocular injection, intravitreal suspension, or intravitreal implant. This review describes each of the currently available corticosteroid treatment options for uveitis, including favorable and unfavorable characteristics of each as well as applicable clinical trials. The main advantage of corticosteroids as a whole is their ability to quickly and effectively control inflammation early on in the course of uveitis. However, they can have serious side effects, whether localized to the eye (such as cataract and elevated intraocular pressure) or systemic (such as osteonecrosis and adrenal insufficiency) and in the majority of cases of uveitis are not an appropriate option for long-term therapy.

Nanoformulations for Ocular Delivery of Drugs - A Patent Perspective

Efficient delivery of ocular therapeutics with improved efficacy, enhanced bioavailability, and acceptable patient compliance presents unique challenges. This can be attributed to the presence of protective mechanisms, physicobiological barriers, and structural obstacles in the eye. Nanotherapeutic interventions have been explored extensively over the past few years to overcome these limitations. The present review focusses on the nanoformulations developed for the diagnosis and treatment of various ocular diseases besides providing an in-depth insight into the patents reported for the same.

Corticosteroids in ophthalmology: drug delivery innovations, pharmacology, clinical applications, and future perspectives

Corticosteroids remain the mainstay of the treatment for various ocular conditions affecting the ocular surface, anterior and posterior segments of the eye due to their anti-inflammatory, anti-oedematous, and anti-neovascularization properties. Prednisolone, prednisolone acetate, dexamethasone, triamcinolone acetonide, fluocinolone acetonide, and loteprednol etabonate are amongst the most widely used ophthalmic corticosteroids. Corticosteroids differ in their activity and potency in the eye due to their inherent pharmacological and pharmaceutical differences. Different routes and regimens are available for ocular administration of corticosteroids. Conventional topical application to the eye is the route of choice when targeting diseases affecting the ocular surface and anterior segment, while periocular, intravitreal, and suprachoroidal injections can be potentially effective for posterior segment diseases. Corticosteroid-induced intraocular pressure elevation and cataract formation remain the most significant local risks following topical as well as systemic corticosteroid administration. Invasive drug administration via intracameral, subconjunctival, and intravitreal injection can enhance ocular bioavailability and minimize dose and dosing frequency of administration, yet may exacerbate ocular side effects of corticosteroids. This review provides a critical appraisal of the ophthalmic uses of corticosteroid, routes of administration, drug delivery fundamentals and novel ocular implantable steroid delivery systems, factors influencing side effects, and future perspectives for ocular corticosteroid therapy.

Advances in ocular drug delivery systems

Recent advances in pharmacological agents have led to successful treatment of a variety of retinal diseases such as neovascular age-related macular degeneration (AMD), diabetic macular oedema (DMO), and retinal vascular occlusions (RVO). These treatments often require repeated drug injections for an extended period of time. To reduce these repeated treatment burdens, minimally invasive drug delivery systems are needed. An ideal therapy should maintain effective levels of drug for the intended duration of treatment following a single application, recognising that a significant number of months of therapy may be required. There are numerous approaches under investigation to improve treatment options. This review will highlight the advantages and limitations of selected drug delivery systems of novel biomaterial implants and depots. The main emphasis will be placed on less invasive, longer acting, sustained release formulations for the treatment of retinal disorders.

Preliminary evaluation of YUTIQ™ (fluocinolone acetonide intravitreal implant 0.18 mg) in posterior uveitis

Uveitis is a major cause of ocular morbidity, potentially leading to significant visual impairment. The recent adoption of alternative drug delivery options has led to the development of new sustained-delivery corticosteroid systems, able to manage successfully chronic noninfectious posterior uveitis. The treatment goal is to target the site of inflammation with low dose of corticosteroids, delivered over an extended period of time, to minimize the cumulative damage resulting from repeated recurrences, reducing both injections frequency and ocular side effects. This article will review the pharmacology and preliminary clinical data of the 0.18 mg fluocinolone acetonide intravitreal implant (YUTIQ™), to show its efficacy and safety in the treatment of noninfectious posterior uveitis.

Prevention of cisplatin-induced hearing loss by extended release fluticasone propionate intracochlear implants

OBJECTIVE

Cisplatin is a chemotherapeutic drug known to induce hearing loss. Although corticosteroids may help to mitigate the ototoxic side effects of cisplatin, there are complications associated with their systemic and prolonged use. The goal of this study is to test the efficacy of extended-release fluticasone propionate intracochlear implant particles to protect against cisplatin-induced hearing loss.

METHODS

We used guinea pigs (n = 9) injected with cisplatin (IP, 12 mg/kg weight). Fluticasone particles were delivered to the cochlear scala tympani through the round window membrane into the right ears of the guinea pigs (left ears being used as a control) two weeks prior to cisplatin administration, and hearing function was evaluated by ABR and DPOAE before implantation, immediately before cisplatin administration, and 2 weeks after the challenge with cisplatin. Data was statistically evaluated using paired t-test analysis.

RESULTS

No significant differences were observed in ABR threshold between control and implanted ears on day 14 (23.9 ± 2.3 dB vs. 25.6 ± 1.3 dB, P = 0.524), whereas the significant cisplatin-induced hearing loss in control animals (23.9 ± 2.3 dB at day 14 vs. 40.7 ± 2.5 dB at day 28, P ≤ 0.0001) was prevented in implanted animals (25.6 ± 1.3 dB at day 14 vs. 25.0 ± 3.1 at day 28, P ≥ 0.85). A similar, though not statistically significant, trend was observed in DPOAE responses in untreated ears (7.9 ± 5.8 dB at day14 vs. -0.5 ± 5.3 dB at day 28, P = 0.654) as compared to treatment (11.1 ± 3.4 dB at day 14 vs. 13.6 ± 4.8 dB at day 28, P = 0.733).

CONCLUSION

These results suggest that fluticasone intracochlear implants are safe and able to provide effective otoprotection against cisplatin-induced hearing loss in the guinea pig model.

Pharmacology of Corticosteroids for Diabetic Macular Edema

Purpose

Corticosteroids remain the mainstay of treatment for inflammatory diseases almost 80 years after their first clinical use. Topical ophthalmic formulations of corticosteroids have been available to treat disease of the anterior segment of the eye, but the approval of corticosteroids to treat vitreoretinal diseases, including vein occlusion, diabetic macular edema, and uveitis, has occurred only recently. Although most diseases respond to corticosteroid therapy, some patients are resistant to this therapy and side effects, including cataract and elevated intraocular pressure, can limit their use. The purpose of this review is to detail the basic science of corticosteroids focusing on differences in potency, drug delivery, pharmacokinetics, and gene activation, and how these differences affect safety and efficacy in the treatment of diabetic macular edema.

Methods

A review was conducted of basic science and pharmacology of the corticosteroids used to treat diabetic macular edema.

Results

Clinically available corticosteroids not only have differing potency and pharmacokinetics, but also activate different genes in different target tissues. These differences are associated with distinct efficacy, pharmacokinetic, and safety profiles. It is important to understand these differences in selecting corticosteroids to treat diabetic macular edema.

Conclusions

Recent advances in our understanding of the basic science of corticosteroids can explain clinical differences in these agents regarding efficacy and safety. Importantly, this understanding should allow the future discovery of additional novel corticosteroids to treat diabetic macular edema.

Ahmed glaucoma valve in uveitic patients with fluocinolone acetonide implant-induced glaucoma: 3-year follow-up

Purpose

To evaluate the efficacy and safety of Ahmed glaucoma valve (AGV) in eyes with noninfectious uveitis that had fluocinolone acetonide intravitreal implant (Retisert™)-induced glaucoma.

Methods

This retrospective study reviewed the safety and efficacy of AGV implantation in patients with persistently elevated intraocular pressure (IOP) after implantation of a fluocinolone acetonide intravitreal implant at the Massachusetts Eye Research and Surgery Institution between August 2006 and November 2015.

Results

Nine patients with 10 uveitic eyes were included in this study, none of which had preexisting glaucoma in the study eye. Mean patient age was 42 years; 6 patients were female and 3 were male. Baseline mean IOP was 30.6 mmHg prior to AGV placement while mean IOP-lowering medications were 2.9. In the treatment groups, there was a statistically significant reduction in post-AGV IOP. IOP was lowest at 1-week after AGV implantation (9.0 mmHg). Nine out of 10 eyes achieved an IOP below target value of 22 mmHg and/or a 20% reduction in IOP from baseline 1 month and 1 year following AGV placement. All other postoperative time points showed all 10 eyes reaching this goal. A statistically significant decrease in IOP-lowering medication was seen at the 1-week, 1-month, and 3-year time points compared to baseline, while a statistically significant increase was seen at the 3-month, 6-month, and 2-year post-AGV time points. No significant change in retinal nerve thickness or visual field analysis was found.

Conclusion

AGV is an effective and safe method of treatment in fluocinolone acetonide intravitreal implant-induced glaucoma. High survival rate is expected for at least 3 years.

Modern Therapeutic Approaches for Noninfectious Ocular Diseases Involving Inflammation

Dry eye disease, age-related macular degeneration, and uveitis are ocular diseases that significantly affect the quality of life of millions of people each year. In these diseases, the action of chemokines, proinflammatory cytokines, and immune cells drives a local inflammatory response that results in ocular tissue damage. Multiple therapeutic strategies are developed to either address the symptoms or abate the underlying cause of these diseases. Herein, the challenges to deliver drugs to the relevant location in the eye for each of these diseases are reviewed along with current and innovative therapeutic approaches that attempt to restore homeostasis within the ocular microenvironment.

A retrospective study on the outcomes of Ahmed valve versus Ahmed valve combined with fluocinolone implant in uveitic glaucoma

Purpose

To compare the intraocular pressure (IOP) outcomes of Ahmed glaucoma valve (AGV) surgery alone versus AGV with fluocinolone implant in uveitic glaucoma patients.

Methods

We identified uveitic glaucoma patients with AGV surgery alone and AGV surgery combined with fluocinolone implant from the Massachusetts Eye and Ear Ocular Inflammation Database. Demographic information, visual acuity, and IOP were recorded at preoperative visits and 1, 6, and 12 months after surgery. Incidence of hypertensive phase, defined as an IOP of >21 mm Hg or use of additional treatment to lower IOP occurring any time between 7 days to 6 months postoperatively, was investigated. Multilevel mixed effects models were performed to compare the outcomes between groups.

Results

Eighteen eyes of 13 uveitic glaucoma patients with 1-year follow-up data were included. There were 11 eyes of 9 patients (mean age, 56.5 years; 63.6% male) in the AGV group and 7 eyes of 4 patients (mean age, 61.3 years; 71.4% male) in the AGV + fluocinolone group. There was no significant difference in visual acuity change at 1 year after surgery between groups (P = 0.25), although visual acuity improvement was significant in the AGV group (P = 0.01). The hypertensive phase occurred in 91% of AGV patients and 43% of AGV + fluocinolone patients (P = 0.30), with onset of 8-40 days (mean, 18 days) after surgery. IOP and number of glaucoma medications decreased at the 1-year postoperative visits in both the AGV group (P < 0.0001, P < 0.0001) and the AGV + fluocinolone group (P = 0.001, P < 0.0001). Compared to the AGV group, the AGV + fluocinolone group used fewer glaucoma medications (0.28 vs 1.30 [P = 0.01]) and had better inflammation control (P = 0.02). The surgical complication rates were similar between groups.

Conclusions

In uveitic glaucoma, AGV with fluocinolone achieves a similar, desired IOP control but with fewer glaucoma medications than AGV alone.

Fluocinolone acetonide for the treatment of diabetic macular edema

INTRODUCTION

Fluocinolone acetonide intravitreal implant is a non-erodible implant approved for the treatment of diabetic macular edema (DME) insufficiently responsive to available therapies. Areas covered: The injectable intravitreal implant releases fluocinolone acetonide at an average rate of 0.2 µg/day for at least 36 months. The two pooled pivotal FAME trials showed that, in patients with DME previously treated with laser photocoagulation, fluocinolone acetonide intravitreal implant was more beneficial than sham injection when looking at the proportion of patients with an improvement from baseline in visual acuity of more than 15 letters at 24 months and at 36 months. Cataract (82%) and intraocular pressure (IOP) elevation (37%) were the most common adverse events. Raised IOP was mostly treated with IOP-lowering medications, with <5% of eyes requiring incisional IOP-lowering surgery. FAME trial program results are confirmed by a series of real-world studies in eyes with chronic/recalcitrant DME. Expert opinion: data indicate that fluocinolone acetonide intravitreal implant is a useful second-line option for the treatment of DME.

Corticosteroid Treatment in Diabetic Macular Edema

Diabetic macular edema is the most common cause of visual impairment in patients with diabetes mellitus. The pathogenesis of macular edema is complex and multifactorial. For many years, laser photocoagulation has been considered the standard therapy for the treatment of diabetic macular edema; however, few patients achieve significant improvements in visual acuity. Today the intravitreal administration of anti-inflammatory or anti-angiogenic agents together with the use of laser photocoagulation represents the standard of care for the treatment of this complication. The intravitreal route of administration minimizes the systemic side effects of corticosteroids. Steroid-related ocular side effects are elevated intraocular pressure and cataract, while injection-related complications include endophthalmitis, vitreous hemorrhage, and retinal detachment. In order to reduce the risks and complications, intravitreal implants have been developed recently to provide sustained release of corticosteroids and reduce repeated injections for the management of diabetic macular edema. In this review, the efficacy, safety, and therapeutic potential of intravitreal corticosteroids in diabetic macular edema are discussed with a review of recent literature.

New Drugs and New Posterior Delivery Methods in CME

PURPOSE

To discuss the characteristics, indications and adverse events (AEs) of sustained-release corticosteroid devices for the treatment of cystoid macular edema (CME).

RECENT FINDINGS

Ozurdex® is approved for the treatment of diabetic macular edema (DME), retinal vein occlusion related-CME and noninfectious posterior uveitis (NIPU). It releases dexamethasone over a maximum period of 6 months making repeated intravitreal injections necessary for recurrent CME. Iluvien® releases fluocinolone for up to 36 months and is effective for the treatment of chronic DME. Retisert® (Bausch & Lomb, Rochester, NY) also releases fluocinolone, and is approved for chronic NIPU. Both Iluvien® and Retisert® are non-biodegradable devices and are highly associated with cataract and glaucoma.

SUMMARY

Long-acting intraocular corticosteroid formulations offer a more predictable drug-release profile and reduced dosing frequency in comparison to conventional formulations of the same compounds but the risk-benefit ratio must be taken into consideration previous to the implantation of those devices.

Drug delivery to the eye: what benefits do nanocarriers offer?

Ocular drug delivery has seen several advances in the past few decades, with respect to new drugs, improved formulations, targeted delivery, as well as exploration of new routes of drug administration. New materials have been explored for encasing existing drugs, which can enhance treatment by increasing bioavailability, decreasing toxicity, providing better tissue adherence, targeted delivery as well as increased duration of action. The challenges and requirements are different for the anterior and posterior ocular segments. This review summarizes the recent advances in sustained ocular therapy, both to the anterior and posterior segments, which have been made possible, thanks to nanotechnology. We also discuss the distribution and fate of these nanocarriers themselves, postadministration, as well as clearance from ocular tissues.

INTRAVITREAL CORTICOSTEROIDS IN DIABETIC MACULAR EDEMA: PHARMACOKINETIC CONSIDERATIONS

PURPOSE

To review the relationship between kinetics, efficacy, and safety of several corticosteroid formulations for the treatment of diabetic macular edema.

METHODS

Reports of corticosteroid use for the treatment of diabetic macular edema were identified by a literature search, which focused on the pharmacokinetics, efficacy, and safety of these agents in preclinical animal models and clinical trials.

RESULTS

Available corticosteroids for diabetic macular edema treatment include intravitreal triamcinolone acetonide, dexamethasone, and fluocinolone acetonide. Because of differences in solubility and bioavailability, various delivery mechanisms are used. Bioerodible delivery systems achieve higher maximum concentrations than nonbioerodible formulations. There is a relationship between visual gains and drug persistence in the intravitreal compartment. Safety effects were more complex; level of intravitreal triamcinolone acetonide exposure is related to development of elevated intraocular pressure and cataract; this does not seem to be the case for dexamethasone, where two different doses showed similar mean intraocular pressure and incidence of cataract surgery. With fluocinolone acetonide, rates of intraocular pressure elevations requiring surgery seem to be dose related; rates of cataract extraction were similar regardless of dose.

CONCLUSION

Available corticosteroids for diabetic macular edema exhibit different pharmacokinetic profiles that impact efficacy and adverse events and should be taken into account when developing individualized treatment plans.

Ocular pharmacokinetics of fluocinolone acetonide following Iluvien implantation in the vitreous humor of rabbits

PURPOSE

The purpose of this study was to evaluate the systemic and ocular pharmacokinetics (PK) of fluocinolone acetonide (FAc) following administration of Iluvien(®) intravitreal implants.

METHODS

The FAc intravitreal implant was administered to rabbits in 3 doses (0.2, 0.5, and 1.0 μg/day). The concentration of FAc was measured by a validated liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method in plasma and ocular tissues at various time points through month 24.

RESULTS

Following administration of the 0.2 μg/day implant, FAc levels peaked in most tissues at day 2 or 8, reached approximate steady state levels by month 3 and very gradually decreased over the duration of the study. The FAc level in the aqueous humor was not measurable at most time points in the rabbit. FAc was still present in most ocular tissues at 2 years. The 0.5 and 1.0 μg/day dose groups followed the same pattern through month 9. The elimination half lives in the tissues for which it was measurable were greater than 83 days. Exposure to FAc was highest in the choroid/retinal pigment epithelium for all doses, followed by lens and retina.

CONCLUSIONS

The results of this study demonstrate sustained delivery of FAc from the Iluvien intravitreal implant in the ocular tissue of rabbits. Retina and lens FAc levels with the Iluvien implant were approximately 1/10 those reported with the Retisert(®) implant. FAc levels in the aqueous were not measureable with Iluvien where they were measured for 12 months with Retisert.

Efficacy and tolerability of bilateral sustained-release dexamethasone intravitreal implants for the treatment of noninfectious posterior uveitis and macular edema secondary to retinal vein occlusion

Purpose

To report our experience with bilateral placement of dexamethasone 0.7 mg (DEX) sustained-release intravitreal implant in the management of noninfectious posterior uveitis or macular edema secondary to retinal vein occlusion.

Methods

A retrospective chart review of patients with bilateral noninfectious posterior uveitis and macular edema secondary to retinal vein occlusion who were treated with DEX intravitreal implant was performed. Ocular side effects such as intraocular pressure (IOP), cataract, and tolerability of bilateral injections was reviewed.

Results

Twenty-two eyes of eleven patients treated with a total of 32 DEX implants were included. Ten of eleven patients received bilateral implants due to active noninfectious uveitis while the other demonstrated macular edema in both eyes following separate central retinal vein occlusions. Among the patients with bilateral uveitis, the mean interval between DEX implant in the initial eye and the subsequent DEX in the fellow eye was 15.6 days (range 2–71 days). Seven of the ten patients received the second implant in the fellow eye within 8 days of the initial implantation. None of the patients had bilateral implantations on the same day. Seven eyes required reimplantation for recurrence of inflammation (mean interval between first and repeat implantation was 6.00±2.39 months). Following single or, in the case of the aforementioned seven eyes, repeat DEX implantation, all 20 uveitic eyes demonstrated clinical and/or angiographic evidence of decreased inflammation in the form of reduction in vitreous cells on slit lamp ophthalmoscopy, macular edema on ophthalmoscopy, or optical coherence tomography and/or disc and vascular leakage on fluorescein angiography. The mean follow-up for all eyes after initial implantation was 23.57 months (range 1–48 months). IOP was significantly higher (P=0.028) at 6 months (16.62 mmHg ±5.97) but not (P=0.82) at most recent follow-up (14.9±3.37 mmHg) when compared with baseline (14.68±3.02 mmHg). Four eyes (18.2%) required initiation of IOP-lowering medications. During the follow-up period, no eyes underwent filtration or cataract extraction. No serious ocular adverse effects were noted during the follow-up period.

Conclusion

In patients with bilateral noninfectious posterior uveitis and macular edema secondary to vein occlusion, bilateral injection of DEX intravitreal implant was well tolerated and had an acceptable safety profile.

Sustained-release fluocinolone acetonide intravitreal insert for macular edema: clinical pharmacology and safety evaluation

INTRODUCTION

Inflammation plays a key role in the pathological processes leading to macular edema. Sustained release, low-dose intraocular corticosteroid delivery devices provide long-term anti-inflammatory therapy. Recently, a novel fluocinolone acetonide intravitreal insert (FAi, Iluvien), has been introduced with promising long-term results in the treatment of macular edema.

AREAS COVERED

An extensive review of the literature in the English language was performed to provide comprehensive information on the pharmacological properties of FAi and its safety and efficacy data from various multi-center randomized clinical trials.

EXPERT OPINION

The FAc, Retisert is a sustained-release device that is surgically implanted in the vitreous and has been approved by the US FDA for the treatment of non-infectious intermediate, posterior or panuveitis. FAi was developed after FAc and is an intravitreal corticosteroid delivery system that allows controlled release of therapeutic levels of fluocinolone acetonide (FA). Initial efficacy and safety data suggest that this delivery system maintains clinical effectiveness for up to 3 years after a single delivery of the device. This second-generation fluocinolone delivery device has shown superior safety results in clinical trials compared to the previous version of the higher dose FAc (0.59 mg). Sustained delivery preparations may help to reduce the treatment burden and its associated risks by decreasing the frequency of intravitreal injections. However, much needs to be learnt from additional clinical trials, post-marketing surveillance and results of extension studies. Concerns of intravitreal corticosteroids, such as cataract and increase in intraocular pressure, remain major challenges for this therapeutic strategy.

Current nanotechnology approaches for the treatment and management of diabetic retinopathy

Diabetic retinopathy (DR) is a consequence of diabetes mellitus at the ocular level, leading to vision loss, and contributing to the decrease of patient's life quality. The biochemical and anatomic abnormalities that occur in DR are discussed in this review to better understand and manage the development of new therapeutic strategies. The use of new drug delivery systems based on nanoparticles (e.g. liposomes, dendrimers, cationic nanoemulsions, lipid and polymeric nanoparticles) is discussed along with the current traditional treatments, pointing out the advantages of the proposed nanomedicines to target this ocular disease. Despite the multifactorial nature of DR, which is not entirely understood, some strategies based on nanoparticles are being exploited for a more efficient drug delivery to the posterior segment of the eye. On the other hand, the use of some nanoparticles also seems to contribute to the development of DR symptoms (e.g. retinal neovascularization), which are also discussed in light of an efficient management of this ocular chronic disease.

Ocular delivery of macromolecules

Biopharmaceuticals are making increasing impact on medicine, including treatment of indications in the eye. Macromolecular drugs are typically given by physician-administered invasive delivery methods, because non-invasive ocular delivery methods, such as eye drops, and systemic delivery, have low bioavailability and/or poor ocular targeting. There is a need to improve delivery of biopharmaceuticals to enable less-invasive delivery routes, less-frequent dosing through controlled-release drug delivery and improved drug targeting within the eye to increase efficacy and reduce side effects. This review discusses the barriers to drug delivery via various ophthalmic routes of administration in the context of macromolecule delivery and discusses efforts to develop controlled-release systems for delivery of biopharmaceuticals to the eye. The growing number of macromolecular therapies in the eye needs improved drug delivery methods that increase drug efficacy, safety and patient compliance.

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.

Sustained-release corticosteroid options

Sustained-release corticosteroid treatment has shown to be a promising strategy for macular edema due to retinovascular disease (i.e., diabetes and retinal vein occlusion) and for the treatment of noninfectious posterior uveitis. Clinicians now have the option of three sustained-release corticosteroid implants: Ozurdex (Allergan Inc., Irvine, CA) which releases dexamethasone and two devices that release fluocinolone acetonide, Retisert (Bausch & Lomb, Rochester, NY), and Iluvien (Alimera Science, Alpharetta, GA). Each has different physical characteristics and duration effect and has been approved for different indications. Herein we provide a summary of the current clinical knowledge regarding these implants.

Advances in ocular drug delivery: emphasis on the posterior segment

INTRODUCTION

Recent advances in pharmacological therapies to treat ocular diseases such as glaucoma, age-related macular degeneration, diabetic macular edema and retinal vascular occlusions have greatly improved the prognosis for these diseases. Due to these advances in pharmacological therapy, there is a great deal of interest in minimally invasive delivery methods, which has generated rapid developments in the field of ocular drug delivery.

AREAS COVERED

This review will summarize currently available and recent developments for ocular drug delivery to both the anterior and posterior segments. Modes of delivery, including topical, systemic, transcleral/periocular and intravitreal, will be discussed and corresponding examples will be given. This review will highlight the advantages and disadvantages of each mode of delivery and discuss strategies to address these issues.

EXPERT OPINION

An ideal therapy should maintain effective levels of drug for the intended duration of treatment following a single application, yet a significant number of months of therapy may be required. There are numerous approaches under investigation to improve treatment options. From the use of novel biomaterial implants and depots for sustained release, to prodrug formations, to iontophoresis to improve drug delivery, the main emphasis will continue to be placed on less invasive, longer acting, sustained release formulations in the treatment of numerous ocular disorders.

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.

Birdshot uveitis: current and emerging treatment options

Birdshot chorioretinopathy is a relatively uncommon subtype of idiopathic posterior uveitis with distinct clinical characteristics and a strong genetic association with the Human Leukocyte Antigen (HLA)-A29 allele. The diagnosis remains clinical and is based on the presence of typical clinical features, including multiple, distinctive, hypopigmented choroidal lesions throughout the fundus. The long-term visual prognosis of this disorder, however, remains guarded – central visual acuity can be preserved until late in the disease and it is not uncommon for patients to receive inadequate immunosuppressive treatment, leading to a poor long-term outcome in which peripheral retinal damage eventually leads to visual deterioration. Birdshot chorioretinopathy has proven a particularly attractive area of study within the field of uveitis, as it is a relatively easily defined disease with an associated human leukocyte antigen haplotype. Despite this, however, the immune mechanisms involved in its pathogenesis remain unclear, and some patients continue to lose retinal function despite therapy with corticosteroids and conventional immunosuppressive agents. Laboratory research continues to investigate the underlying mechanisms of disease, and clinical research is now being driven to improve the phenotyping and monitoring of this condition as, in the era of so-called personalized medicine, it is becoming increasingly important to identify patients at risk of visual loss early so that they can be treated more aggressively with targeted therapies such as the newer biological agents. This approach requires the formation of collaborative groups, as the relative rarity of the condition makes it difficult for one center to accumulate enough patients for worthwhile studies. Nevertheless, results obtained with newer therapies, such as biological agents directed against particular cytokines or cell-surface receptors, demonstrate ever improving control of the inflammation in refractory cases, providing hope that the outlook for visual function in this condition can only improve.

Critical assessment of implantable drug delivery devices in glaucoma management

Glaucoma is a group of heterogeneous disorders involving progressive optic neuropathy that can culminate into visual impairment and irreversible blindness. Effective therapeutic interventions must address underlying vulnerability of retinal ganglion cells (RGCs) to degeneration in conjunction with correcting other associated risk factors (such as elevated intraocular pressure). However, realization of therapeutic outcomes is heavily dependent on suitable delivery system that can overcome myriads of anatomical and physiological barriers to intraocular drug delivery. Development of clinically viable sustained release systems in glaucoma is a widely recognized unmet need. In this regard, implantable delivery systems may relieve the burden of chronic drug administration while potentially ensuring high intraocular drug bioavailability. Presently there are no FDA-approved implantable drug delivery devices for glaucoma even though there are several ongoing clinical studies. The paper critically assessed the prospects of polymeric implantable delivery systems in glaucoma while identifying factors that can dictate (a) patient tolerability and acceptance, (b) drug stability and drug release profiles, (c) therapeutic efficacy, and (d) toxicity and biocompatibility. The information gathered could be useful in future research and development efforts on implantable delivery systems in glaucoma.

Local therapies for inflammatory eye disease in translation: past, present and future

Despite their side-effects and the advent of systemic immunosuppressives and biologics, the use of corticosteroids remains in the management of patients with uveitis, particularly when inflammation is associated with systemic disease or when bilateral ocular disease is present. The use of topical corticosteroids as local therapy for anterior uveitis is well-established, but periocular injections of corticosteroid can also be used to control mild or moderate intraocular inflammation. More recently, intraocular corticosteroids such as triamcinolone and steroid-loaded vitreal inserts and implants have been found to be effective, including in refractory cases. Additional benefits are noted when ocular inflammation is unilateral or asymmetric, when local therapy may preclude the need to increase the systemic medication.

Implants in particular have gained prominence with evidence of efficacy including both dexamethasone and fluocinolone loaded devices. However, an appealing avenue of research lies in the development of non-corticosteroid drugs in order to avoid the side-effects that limit the appeal of injected corticosteroids. Several existing drugs are being assessed, including anti-VEGF compounds such as ranibizumab and bevacizumab, anti-tumour necrosis factor alpha antibodies such as infliximab, as well as older cytotoxic medications such as methotrexate and cyclosporine, with varying degrees of success. Intravitreal sirolimus is currently undergoing phase 3 trials in uveitis and other inflammatory pathways have also been proposed as suitable therapeutic targets. Furthermore, the advent of biotechnology is seeing advances in generation of new therapeutic molecules such as high affinity binding peptides or modified high affinity or bivalent single chain Fab fragments, offering higher specificity and possibility of topical delivery.

A comparison between the fluocinolone acetonide (Retisert) and dexamethasone (Ozurdex) intravitreal implants in uveitis

PURPOSE

To evaluate the efficacy and safety of the fluocinolone acetonide (Retisert) implant compared with the dexamethasone (Ozurdex) implant in patients with noninfectious uveitis.

DESIGN

Comparative case series.

STUDY PARTICIPANTS

Twenty-seven eyes received either the fluocinolone acetonide (FA) (n=16) or dexamethasone (n=11) implant.

METHODS

Chart review of patients at the Massachusetts Eye Research and Surgery Institution (MERSI) was done and patients were selected and matched according to age, sex, and type of uveitis. Eyes that received either the FA or dexamethasone implant, with follow-up ranging from 6 months to 2 years, were included.

MAIN OUTCOME MEASURE

The recurrence rate of uveitis after implantation.

RESULTS

There were no significant differences in the baseline demographic characteristics. The majority of cases were idiopathic panuveitis, with 36.4% and 31.3% of eyes in the Ozurdex and Retisert groups, respectively. Recurrence rates of uveitis were 1.7 and 0.5 per 100 person-months in the Retisert and Ozurdex groups, respectively, with Retisert-implanted eyes 3.16 times more at risk of recurrence; however, this difference was not statistically significant (P=0.41). No significant differences were seen in terms of improvement in inflammatory score and best-corrected visual acuity (BCVA). The median survival time for a second implant was 13 and 28 months for the Ozurdex and Retisert groups, respectively (P=0.0028). Eyes with the Ozurdex were 5 times more likely to receive a second implant (P=0.02). No eyes in the Ozurdex group needed additional glaucoma medications, surgery, or laser compared to 44% of eyes in the Retisert group. Eyes with the Retisert implant had a statistically higher rate of having more glaucoma medications, surgery, or laser (P=0.02). In the Ozurdex group, 50% of phakic eyes at baseline had cataract progression and subsequent surgery compared with 100% of Retisert phakic eyes. Eyes with the Retisert implant are 4.7 times more at risk of cataract progression (P=0.04).

CONCLUSIONS

The dexamethasone (Ozurdex) implant seems comparable to the fluocinolone acetonide (Retisert) implant in preventing recurrence of noninfectious uveitis and in improving inflammation and BCVA. However, there were higher rates of cataract progression and need for glaucoma medications, laser, and surgery with the Retisert implant.

Diabetic macular edema: new trends in management

The treatment of diabetic macular edema may be evolving from a laser ablative approach into a pharmacotherapeutic approach. The exponential growth that has occurred over the past decade in the retinal pharmacotherapy field has led to the development of several pharmacotherapies for retinal vascular diseases such as diabetic macular edema. Many of these agents, in the form of intravitreal injections or sustained delivery devices, have already undergone clinical trial testing for safety and efficacy and many others are currently being similarly evaluated. Some of these agents have proven to be more efficacious than traditional laser therapy, and it is possible that traditional laser therapy for diabetic macular edema may be abandoned altogether in the near future, especially with the introduction of the micropulse laser. However, more research and experience is still needed in order to determine the best treatment agent or combination of therapeutic modalities, as well as the best treatment regimen for a given patient. In this article, we briefly review the major new developments in the field of diabetic macular edema treatment. In addition, we touch on some of the promising forthcoming therapies.

Intraocular corticosteroids for posterior segment disease: 2012 update

INTRODUCTION

Diabetic macular edema (DME), cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO) and uveitis are responsible for severe visual impairment worldwide. In some patients with these conditions, treatment with intraocular corticosteroids may be beneficial. Although off-label use of these agents has occurred for many years, novel agents including preservative-free and sustained-release intravitreal implants are currently being studied in clinical trials (CTs).

AREAS COVERED

This paper reviews the use of CTs for vitreoretinal (VR) diseases including choroidal neovascularization, CME, DME, RVO and posterior uveitis. It also discusses the use of corticosteroids for treating VR disease, including dexamethasone, fluocinolone acetonide, intravitreal implants and triamcinolone acetonide.

EXPERT OPINION

Used alone, intravitreal corticosteroids may benefit disorders such as DME, RVO and uveitis compared with standard therapy. Cases of exudative AMD non-responsive to standard treatment may benefit from combination therapy, including usage of intravitreal corticosteroid injections. Intraoperative use of these agents may aid visualization of retinal structures. Sustained-release intraocular implants have been approved for posterior uveitis and RVO associated with macular edema. In spite of this, most intraocular corticosteroids have a limited duration of action along with significant side effects, including cataract and glaucoma. Currently, intravitreal corticosteroid usage for DME is considered off-label.

Review and update of intraocular therapy in noninfectious uveitis

PURPOSE OF REVIEW

To review new clinically relevant data regarding the intraocular treatment of noninfectious uveitis.

RECENT FINDINGS

Triamcinolone acetonide, the most commonly used intravitreal corticosteroid for treatment of uveitis and uveitic macular oedema has a limited duration of action and is associated with a high risk of corticosteroid-induced intraocular pressure (IOP) rise and cataract. Recent advances have led to the development of sustained-release corticosteroid devices using different corticosteroids such as dexamethasone and fluocinolone acetonide. Treatment options for patients who have previously exhibited corticosteroid hypertensive response have also expanded through the use of new noncorticosteroid intravitreal therapeutics such as methotrexate and antivascular endothelial growth factor (anti-VEGF) agents.

SUMMARY

Ozurdex dexamethasone implant appears to have a better safety profile, and a slightly long-lasting effect than triamcinolone acetonide. The Retisert implant allows the release of corticosteroids at a constant rate for 2.5 years, but it requires surgical placement and its use is associated with a very high risk of cataract and requirement for IOP-lowering surgery. For patients who are steroid responders, methotrexate may offer a better alternative to corticosteroid treatment than anti-VEGF agents, but controlled trials are required to confirm this.

Road to remission: a comprehensive review of therapy in uveitis

INTRODUCTION

Although uveitis remains the third leading cause of preventable blindness in the US, the care and management of patients with uveitis and ocular inflammatory disease sit poised to make evolutionary if not revolutionary changes in the years ahead. This review serves to highlight important advances in the pharmacologic options available for the treatment of uveitis and ocular inflammation.

AREAS COVERED

Advances in steroid therapy (both topical and extended delivery), updates in the clinical safety of systemic immune modulation, and the emerging therapies for uveitis and ocular inflammatory disease are some of the areas covered in this review.

EXPERT OPINION

Corticosteroids have been the mainstay in the care of patients with ocular inflammatory disorders for many years. Indeed, some physicians still use only steroids for treating inflamed eyes. However, the mission is remission of all corticosteroids in order to prevent the complications associated with long-term corticosteroid use. The goal is to achieve quiescence through aggressive use of corticosteroids to extinguish the fire and then move along to achieve steroid-free remission through immunosuppressant agents.

Long-term benefit of sustained-delivery fluocinolone acetonide vitreous inserts for diabetic macular edema

OBJECTIVE

To assess the efficacy and safety of intravitreal inserts releasing 0.2 μg/day (low dose) or 0.5 μg/day (high dose) fluocinolone acetonide (FA) in patients with diabetic macular edema (DME).

DESIGN

Two parallel, prospective, randomized, sham injection-controlled, double-masked, multicenter clinical trials.

PARTICIPANTS

Subjects with persistent DME despite at least 1 macular laser treatment were randomized 1:2:2 to sham injection (n = 185), low-dose insert (n = 375), or high-dose insert (n = 393).

METHODS

Subjects received study drug or sham injection at baseline and after 6 weeks were eligible for rescue laser. Based on retreatment criteria, additional study drug or sham injections could be given after 1 year.

MAIN OUTCOME MEASURES

The primary outcome was the percentage of patients with improvement from baseline best-corrected visual acuity (BCVA) in Early Treatment Diabetic Retinopathy Trial (ETDRS) letter score of 15 or more at month 24. Secondary outcomes included other parameters of visual function and foveal thickness (FTH).

RESULTS

The percentage of patients with improvement from baseline ETDRS letter score of 15 or more at month 24 was 28.7 and 28.6 in the low- and high-dose insert groups, respectively, compared with 16.2 in the sham group (P = 0.002 for each). Benefit occurred for both doses compared with sham at 3 weeks and all subsequent time points. The mean improvement in BCVA letter score between baseline and month 24 was 4.4 and 5.4 in the low- and high-dose groups, respectively, compared with 1.7 in the sham group (P = 0.02 and P = 0.016). At all time points compared with sham, there was significantly more improvement in FTH. Subjects requiring cataract surgery were more frequent in the insert groups, and their visual benefit was similar to that of subjects who were pseudophakic at baseline. Glaucoma requiring incisional surgery occurred in 3.7%, 7.6%, and 0.5% of the low-dose, high-dose, and sham groups, respectively.

CONCLUSIONS

Both low- and high-dose FA inserts significantly improved BCVA in patients with DME over 2 years, and the risk-to-benefit ratio was superior for the low-dose insert. This is the first pharmacologic treatment that can be administered by an outpatient injection to provide substantial benefit in patients with DME for at least 2 years.

Intraocular pharmacokinetics of a crystalline lipid prodrug, octadecyloxyethyl-cyclic-cidofovir, for cytomegalovirus retinitis

PURPOSE

To evaluate the intraocular pharmacokinetics of octadecyloxyethyl-cyclic-cidofovir (ODE-cCDV) after intravitreal injection into rabbit eyes.

METHODS

Twenty-seven New Zealand red rabbits (27 eyes) received intravitreal injections of (14)C-labeled ODE-cCDV (100 μg drug suspended in 5% dextrose), and ocular tissues were collected from 3 rabbits at each predetermined time point (1 h, 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 5 weeks, and 9 weeks) after the injection. The eye globes were enucleated, and the vitreous, retina, and choroids were separated and harvested into pre-weighed scintillation vials. Levels of ODE-cCDV were measured by counting in a liquid scintillation counter, and pharmacokinetic (PK) parameters were determined. In addition, 3 eyes of 3 animals were used for autoradiography study at day 1, week 3, and week 6.

RESULTS

ODE-cCDV in vitreous as a whole followed a 2-phase first-order elimination, whereas ODE-cCDV in retina and choroid manifested a nearly steady state during the first 3 weeks and then followed a first-order elimination with the apparent elimination half-life of 10.1 and 7.2 days. For vitreous, apparent elimination half-life was 25 days. However, the drug mean residence time was much longer in retina (17.6 days) and choroid (19.6 days) than that in the vitreous (11.6 days). The drug exposure to the retina [area under the curve (AUC) = 1120837.1 ng · day/mL] was greater than the exposure to the vitreous (AUC = 958645.8 ng · day/mL) and the choroid (AUC = 415407.47).

CONCLUSION

A crystalline lipid prodrug, ODE-cCDV, has longer vitreous half-life than that in other ocular tissues due to its solid drug depot formation in vitreous. Over time, dissolved free ODE-cCDV from drug depot feeds and accumulates in the retina.

Scleral thickness following fluocinolone acetonide implant (Retisert)

PURPOSE

To evaluate whether intravitreal fluocinolone acetonide (FA) implantation (Retisert) leads to scleral thinning.

METHODS

Scleral thickness was measured at the pars plana region (4 quadrants) with anterior segment OCT (Visante) in FA implanted eyes (18) with noninfectious posterior uveitis in comparison to eyes with prior vitrectomy (8), and normal eyes without prior surgery (30).

RESULTS

Mean scleral thickness in normal (nonsurgical) eyes was 0.99/0.93/0.88/0.86, and 0.92 mm in the inferonasal/inferotemporal/superotemporal/superonasal quadrants, and overall, respectively. Sclera was thinner in each quadrant of the FA implanted eyes compared to the fellow or nonsurgical eyes, although none reached statistical significance, as the differences were small. However, a few FA implanted eyes demonstrated more dramatic scleral thinning than others.

CONCLUSIONS

FA implant appears to lead to statistically nonsignificant scleral thinning overall with few exceptions. Clinicians should be aware of potential scleral thinning in select cases, important for reimplantation and long-term follow-up.

Sustained ocular delivery of fluocinolone acetonide by an intravitreal insert

PURPOSE

To compare Iluvien intravitreal inserts that release 0.2 or 0.5 microg/day of fluocinolone acetonide (FA) in patients with diabetic macular edema (DME).

DESIGN

Prospective, randomized, interventional, multicenter clinical trial.

PARTICIPANTS

We included 37 patients with DME.

METHODS

Subjects with persistent DME despite > or = 1 focal/grid laser therapy were randomized 1:1 to receive an intravitreal insertion of a 0.2- or a 0.5-microg/day insert.

MAIN OUTCOME MEASURES

The primary end point was aqueous levels of FA throughout the study with an important secondary outcome of the change from baseline in best-corrected visual acuity (BCVA) at month 12.

RESULTS

The mean aqueous level of FA peaked at 3.8 ng/ml at 1 week and 1 month after administration of a 0.5-microg/day insert and was 3.4 and 2.7 ng/ml 1 week and 1 month after administration of a 0.2-microg/day insert. For both inserts, FA levels decreased slowly thereafter and were approximately 1.5 ng/ml for each at month 12. The mean change from baseline in BCVA was 7.5, 6.9, and 5.7 letters at months 3, 6, and 12, respectively, after administration of a 0.5 microg/day-insert and was 5.1, 2.7, and 1.3 letters at months 3, 6, and 12, respectively, after administration of a 0.2-microg/day insert. There was a mild increase in mean intraocular pressure after administration of 0.5-microg/day inserts, but not after administration of 0.2-microg/day inserts.

CONCLUSIONS

The FA intravitreal inserts provide excellent sustained intraocular release of FA for > or = 1 year. Although the number of patients in this trial was small, the data suggest that the inserts provide reduction of edema and improvement in BCVA in patients with DME with mild effects on intraocular pressure over the span of 1 year.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.