Development of a dexamethasone intravitreal implant for the treatment of noninfectious posterior segment uveitis

Reactive Oxygen Species-Responsive Dual Anti-Inflammatory and Antioxidative Nanoparticles for Anterior Uveitis

Anterior uveitis (AU) is an immune-mediated inflammatory disease that results in iritis, cyclitis, glaucoma, cataracts, and even a loss of vision. The frequent and long-term administration of corticosteroid drugs is limited in the clinic owing to the side effects and patient noncompliance with the drugs. Therefore, specifically delivering drugs to inflammatory anterior segment tissues and reducing the topical application dosage of the drug are still a challenge. Here, we developed dual dexamethasone (Dex) and curcumin (Cur)-loaded reactive oxygen species (ROS)-responsive nanoparticles (CPDC NPs) to treat anterior uveitis. The CPDC NPs demonstrated both anti-inflammatory and antioxidative effects, owing to their therapeutic characteristics of dexamethasone and curcumin, respectively. The CPDC NPs could effectively release dexamethasone and curcumin in the oxidizing physiological environment of the inflammation tissue. The CPDC NPs can effectively internalize by activated macrophage cells, subsequently suppressing the proinflammatory factor expression. Moreover, the CPDC NPs can inhibit ROS and inflammation via nuclear transcription factor E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway activation. In an endotoxin-induced uveitis rabbit model, the CPDC NPs show a therapeutic effect that is better than that of either free drugs or commercial eye drops. Importantly, the CPDC NPs with a lower dexamethasone dosage could reduce the side effects significantly. Taken together, we believe that the dual-drug-loaded ROS-responsive NPs could effectively target and inhibit inflammation and have the potential for anterior uveitis treatment in clinical practice.

Progress in Ocular Drug Delivery: Challenges and Constraints

The eye has several dynamic and static barriers in place to limit the entry of foreign substances including therapeutics. As such, efficient drug delivery, especially to posterior segment tissues, has been challenging. This chapter describes the anatomical and physiological challenges associated with ocular drug delivery before discussing constraints with regard to formulation parameters. Finally, it gives an overview of advanced drug delivery technologies with a specific focus on recently marketed and late-stage clinical trial products.

Intravitreal Fluocinolone 0.19mg Implant in the Management of Chronic Non-Infectious Uveitis: 12-Month Outcomes from a Single Tertiary Centre

AIM

To present efficacy and safety of 0.19 mg fluocinolone acetonide insert (FAi) to treat chronic noninfectious uveitis (NIU) in a single referral center.

METHODS

A retrospective observational clinical study of 11 eyes with NIU complicated by chronic cystoid macular edema (CMO).

RESULTS

The main indication for treatment was chronic CMO in all 11 eyes. The mean central retinal thickness (CRT) at baseline was 435 μm ± 176, improving to 296 μm ± 67 at 12 months. Raised intraocular pressure (IOP) was the commonest adverse event. An IOP >21 mmHg was observed in three eyes, and >30 mmHg in one eye, managed with topical therapy. The mean best corrected visual acuity (BCVA) was stable at 12 months. There were no observed recurrences of uveitis. Two eyes received adjunctive treatment for worsening CRT.

CONCLUSIONS

Our results suggest FAi is an effective maintenance treatment for NIU with favorable functional and anatomical outcomes.

In Vitro and In Vivo Safety of Hyaluronic Acid-Decorated Microparticles for Intravitreal Injection of Palmitoylethanolamide, Citicoline, or Glial-Cell-Derived Neurotrophic Factor

The treatment of posterior eye segment diseases through intravitreal injection requires repeated injections of an active molecule, which may be associated with serious side effects and poor patient compliance. One brilliant strategy to overcome these issues is the use of drug-loaded microparticles for sustained release, aiming at reducing the frequency of injections. Therefore, the aim of this work was to assess the safety features of poly(lactic-co-glycolic acid) (PLGA)-based, hyaluronic acid-decorated microparticles loaded with palmitoylethanolamide (PEA), citicoline (CIT), or glial-cell-derived neurotrophic factor (GDNF). Microparticles were prepared by double emulsion-solvent evaporation and fully characterized for their technological features. Microparticles possessed a satisfactory safety profile in vitro on human retinal pigment epithelial (ARPE-19) cells. Interestingly, the administration of free GDNF led to a loss of cell viability, while GDNF sustained release displayed a positive effect in that regard. In vivo results confirmed the safety profile of both empty and loaded microparticles. Overall, the outcomes suggest that the produced microparticles are promising for improving the local administration of neuroprotective molecules. Further studies will be devoted to assess the therapeutic ability of microparticles.

Intravitreal dexamethasone implants facilitate the management of refractory Behçet's uveitis with vasculitis

To investigate the efficacy and safety of dexamethasone (DEX) implant, Ozurdex ®, as an adjunctive treatment for refractory Behçet's uveitis (BU), a total of 61 patients (80 eyes) were included in this cross-sectional study and divided into the non-DEX and DEX groups. After >12 months of treatment, the improvement in the fluorescein angiography score and vitritis score was significantly higher in the DEX group than in the non-DEX group. Although the posterior capsule opacification score was exacerbated, the rate of low-dose systemic glucocorticoid was higher and the relapse times were fewer in the DEX group. Therefore, Ozurdex® is an effective and safe option for patients with BU that are refractory to systemic immunosuppressant treatments by controlling vasculitis, stabilizing vitreous inflammation, preventing recurrence, and reducing daily glucocorticoid doses.

Drug release mechanisms of high-drug-load, melt-extruded dexamethasone intravitreal implants

Ozurdex is an FDA-approved sustained-release, biodegradable implant formulated to deliver the corticosteroid dexamethasone to the posterior segment of the eye for up to 6 months. Hot-melt extrusion is used to prepare the 0.46 mm × 6 mm, rod-shaped implant by embedding the drug in a matrix of poly(lactic-co-glycolic acid) (PLGA) in a 60:40 drug:polymer ratio by weight. In our previous work, the Ozurdex implant was carefully studied and reverse engineered to produce a compositionally and structurally equivalent implant for further analysis. In this work, the reverse-engineered implant is thoroughly characterized throughout the in vitro dissolution process to elucidate the mechanisms of controlled drug release. The implant exhibits a triphasic release profile in 37 °C normal saline with a small burst release (1-2 %), a one-week lag phase with limited release (less than10 %), and a final phase where the remainder of the dose is released over 3-4 weeks. The limited intermolecular interaction between dexamethasone and PLGA renders the breakdown of the polymer the dominating mechanism of controlled release. A close relationship between drug release and total implant mass loss was observed. Unique chemical and structural differences were seen between the core of the implant and the implant surface driven by diffusional limitations, autocatalytic hydrolysis, and osmotic effects.

Management of Diabetic Macular Edema: Guidelines from the Emirates Society of Ophthalmology

In the United Arab Emirates, retinopathy has been shown to be present in 19% of the diabetic population, with diabetes identified in up to 40% of individuals aged over 55 years. Despite the prevalence of diabetic retinal diseases, there are no unified national guidelines on the management of diabetic macular edema (DME). These published guidelines are based on evidence taken from the literature and published trials of therapies, and consensus opinion of a representative expert panel with an interest in this condition, convened by the Emirates Society of Ophthalmology. The aim is to provide evidence-based, clinical guidance for the best management of different aspects of DME, with a special focus on vision-threatening diabetic retinopathy. Treatment should be initiated in patients with best-corrected visual acuity 20/30 or worse, and/or features of DME as seen on optical coherence tomography (OCT) with central retinal thickness (CRT) of at least 300 μm or in symptomatic patients with vision better than 20/25, and/or CRT less than 300 μm where there are OCT features consistent with center-involving macular edema. The treatment of DME is effective irrespective of glycated hemoglobin (HbA1c) level, and treatment must not be denied or delayed in order to optimize systemic parameters. All ophthalmic treatment options should be discussed with the patient for better compliance and expectations. Non-center-involving DME can be initially observed until progression toward the center is documented. Macular laser no longer has a primary role in center-involving DME, and anti-vascular endothelial growth factor (anti-VEGF) therapy should be considered as first-line treatment for all patients, unless contraindicated. If anti-VEGF is contraindicated, a steroid dexamethasone implant can be considered for first-line treatment. Recommendations for the treatment of DME in special circumstances and in relapsing and refractory DME are also discussed.

Real-Life Efficacy, Safety, and Use of Dexamethasone Intravitreal Implant in Posterior Segment Inflammation Due to Non-infectious Uveitis (LOUVRE 2 Study)

Introduction

To evaluate real-life efficacy, safety, and treatment patterns with the dexamethasone intravitreal implant (DEX) in posterior segment inflammation due to non-infectious uveitis (treatment-naïve or not) in French clinics.

Methods

In this prospective, multicenter, observational, non-comparative, post-reimbursement study, consecutive patients with posterior segment inflammation due to non-infectious uveitis were enrolled and evaluated at baseline (day 0). Those who received DEX on day 0 were re-evaluated at months 2, 6, and 18. Retreatment with DEX and/or alternative therapies was allowed during follow-up. Primary outcome: patients (%) with at least a 15-letter gain in best corrected visual acuity (BCVA) at 2 months. Secondary outcomes included patients (%) with at least 15-letter BCVA gains at 6 and 18 months; mean BCVA change from baseline at 2, 6, and 18 months; and patients (%) retreated, mean central retinal thickness (CRT), and adverse events (AEs) at all post-baseline visits.

Results

Ninety-seven of 245 enrolled patients with posterior segment inflammation due to non-infectious uveitis (80% previously treated) and disease duration of 5 years (average) received DEX on day 0 and were included in efficacy analyses. At month 2 (n = 91), 20.5% of patients (95% CI 12.0–28.9) gained at least 15 letters from a baseline mean of 60.9 letters; the mean gain was 6.2 letters (95% CI 3.5–8.9). At month 6, 50.0% (n = 38/76) of patients did not receive alternative treatment or DEX retreatment, mostly because inflammation had sufficiently subsided (n = 27/38, 71.1%). Although early study termination prevented efficacy analysis at 18 months (n = 12), CRT reductions persisted throughout follow-up. From baseline to month 18, 21/245 (8.6%) patients had DEX-related AEs; 17/245 (6.9%) had ocular hypertension (most common AE).

Conclusion

LOUVRE 2 confirms DEX efficacy on visual acuity and CRT in predominantly DEX-pretreated patients with relatively old/stabilized uveitis. DEX tolerability was consistent with known/published data, confirming treatment benefits in posterior segment inflammation due to non-infectious uveitis.

ClinicalTrials.gov Identifier

NCT02951975.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-022-00525-8.

Long-term efficacy of dexamethasone intravitreal implant in the treatment of Vogt-Koyanagi-Harada disease relapsing posterior uveitis

Purpose:

To investigate the efficacy and safety of dexamethasone intravitreal implant in the treatment of relapsing posterior uveitis in patients with chronic recurrent Vogt–Koyanagi–Harada (VKH) disease.

Methods:

This was a prospective study of 29 eyes of 16 patients with posterior uveitis in chronic recurrent VKH disease. All patients received previous systemic steroid and immunosuppressive regimens. All patients underwent a comprehensive ophthalmic examination, including best-corrected visual acuity (BCVA), Indocyanine green angiography (ICGA), fundus fluorescein angiography (FFA), and spectral-domain optical coherence tomography (SD-OCT). All patients underwent intravitreal injection with sustained-release dexamethasone 0.7 mg implant (Ozurdex®). Primary outcome measures included mean change in BCVA and central foveal thickness (CFT) at 24 months of follow-up compared to the baseline.

Results:

At 24 month of follow-up, the mean BCVA improved from 0.82 ± 0.13 to 0.38 ± 0.06 logMAR (P < 0.0001). The mean CFT reduced from 505 ± 29 to 244 ± 23 um (P < 0.0001). The mean intraocular pressure (IOP) changed from 15.1 ± 2.2 to 16.9 ± 3.1 mmHg with no significant value (P-value = 0.0955). Twenty-one eyes (72.4%) received one injection, whereas eight eyes (27.6%) required two injections. The mean number of injections was 1.2 ± 0.60. The mean follow-up time was 24.75 ± 0.9 months. No serious ocular or systemic adverse events were noted during the follow-up period. Ocular hypertension was recorded in three (10.3%) eyes and controlled by IOP lowering medications. Cataract progression occurred in 11 (37.9%) eyes.

Conclusion:

Our cohort highlights the beneficial effects of the dexamethasone implant of 0.7 mg in the treatment of VKH disease relapsing posterior uveitis improving visual acuity, reducing macular edema, and minimizing the burden of systemic steroids in this sample study.

An update on long-acting therapies in chronic sight-threatening eye diseases of the posterior segment: AMD, DMO, RVO, uveitis and glaucoma

In the real-world setting, there is suboptimal compliance with treatments that require frequent administration and assessment visits. This undertreatment frequently has negative consequences in eye disease and carries a real risk to vision. For example, patients with glaucoma risk progression of visual loss even with a small number of missed doses, and patients with neovascular age-related degeneration (nAMD) who fail to attend a bi-monthly clinic appointment to receive an intravitreal anti-vascular endothelial growth factor (VEGF) drug injections may lose the initial vision gains in vision. Protracted regular treatment schedules represent a high burden not only for patients and families, but also healthcare professionals, systems, and ultimately society too. There has been a clear need for longer-acting therapies that reduce the frequency, and therefore the burden, of treatment interventions. Several longer-acting interventions for nAMD, diabetic macular oedema, retinal vein occlusion, uveitis and glaucoma have either been developed or are in late-phase development, some of which employ novel mechanisms of actions, and all of which of promise longer (≥3 month) treatment intervals. This review delivers an overview of anti-VEGF agents with longer durations of action, DARPins, bispecific anti-VEGF/Ang2 therapies, anti-PDGF and anti-integrin therapy, Rho-kinase inhibitors, the Port Delivery System, steroids, gene therapy for retina and uveitis, and for glaucoma, ROCK inhibitors, implants and plugs, and SLT laser and MIGS. The review also refers to the potential of artificial intelligence to tailor treatment efficacy with a resulting reduction in treatment burden.

Intracameral sustained release bimatoprost implants (Durysta)

Background: Sustained release drug delivery has the potential to change glaucoma care by decreasing the challenge of medication adherence. Many approaches are in development, but this review focuses on Durysta (Allergan plc, Dublin, Ireland), the only FDA-approved sustained release intracameral treatment available at this time. Key Findings: Durysta is a bimatoprost sustained release (BimSR) intracameral implant. Clinical trials have demonstrated that BimSR implants can provide comparable levels of intraocular pressure (IOP) control as topical eyedrops. BimSR has advantages such as decreasing concerns regarding drop adherence, reducing ocular surface and periocular side effects from topical drops, and decreased daily treatment burden for patients. In addition, studies have shown continued IOP lowering in some eyes during extended follow-up periods when all of the BimSR medication has already been delivered. Hypothesized mechanisms to explain this finding include increased matrix metalloproteinase expression that causes extracellular matrix reorganization to permit greater aqueous outflow, as well as decreased episcleral venous pressure. The major safety concern at this time for Durysta and future intracameral implants is corneal endothelial cell loss, which was worse with repeat BimSR administration compared to single dosing. Several studies are underway to investigate mechanisms of action and to better understand safe and effective dosing of medications in this class.

Intraoperative intravitreal triamcinolone acetonide injection for prevention of postoperative inflammation and complications after phacoemulsification in patients with uveitic cataract

Background

We aimed to evaluate the efficacy and safety of phacoemulsification with intravitreal 3 mg triamcinolone acetonide injection in preventing postoperative inflammation and complications in patients with non-infectious anterior uveitis and panuveitis complicated cataract.

Method

In this retrospective cohort study, 140 uveitic cataract patients who received phacoemulsification and intraocular lens implantation in Shanxi Eye hospital from January 2018 to January 2020 were reviewed. The IVTA group (51 eyes of 41 patients) received intravitreal injection of 3 mg triamcinolone acetonide (TA) at the end of surgery, and the control group (51 eyes of 41 patients) without injection matched by propensity score matching were enrolled. Outcome measures were best corrected visual acuity (BCVA), anterior chamber inflammation, intraocular pressure, corneal endothelial cell density, central macular thickness and complications within 3 months follow-up.

Results

The degree of postoperative anterior chamber inflammation in the IVTA group was lighter than that in the control group (P < 0.05). The postoperative logMAR BCVA of anterior uveitis was better and improved more quickly in the IVTA group(P < 0.05). Postoperative time of using corticosteroids was shorter in the IVTA group as compared to the control group (P < 0.05). The central macular thickness at postoperative month 1 was statistically significantly lower in the IVTA group (P < 0.05). There were no statistically significant differences between the two groups in postoperative corneal endothelial cell density and intraocular pressure (P > 0.05). Two of 51 eyes (3.9%) in the IVTA group and 8 of 51 eyes (15.7%) in the control group had recurrence of uveitis; 6 of 45 eyes (13.3%) in the control group developed cystoid macular edema but none in the IVTA group; 11 of 51 eyes (21.6%) in the IVTA group and 22 of 51 eyes (43.1%) in the control group developed posterior synechiae postoperatively.

Conclusions

Intraoperative Intravitreal injection of 3 mg TA is an effective and safe adjunctive therapy for preventing postoperative inflammation and complications to promote early recovery for anterior uveitis or panuveitis complicated cataract patients following phacoemulsification.

Trial registration

This retrospective cohort study was in accordance with the tenets of the Helsinki Declaration and was approved by the Shanxi Eye Hospital Ethics Committee. Written informed consent was obtained from all participants for their clinical records to be used in this study.

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.

Biotechnology and Biomaterial-Based Therapeutic Strategies for Age-Related Macular Degeneration. Part I: Biomaterials-Based Drug Delivery Devices

Age-related Macular Degeneration (AMD) is an up-to-date untreatable chronic neurodegenerative eye disease of multifactorial origin, and the main causes of blindness in over 65 years old people. It is characterized by a slow progression and the presence of a multitude of factors, highlighting those related to diet, genetic heritage and environmental conditions, present throughout each of the stages of the illness. Current therapeutic approaches, mainly consisting of intraocular drug delivery, are only used for symptoms relief and/or to decelerate the progression of the disease. Furthermore, they are overly simplistic and ignore the complexity of the disease and the enormous differences in the symptomatology between patients. Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, the development of biomaterials-based approaches for a personalized and controlled delivery of therapeutic drugs and biomolecules represents the main challenge for the defeat of this neurodegenerative disease. Here we present a critical review of the available and under development AMD therapeutic approaches, from a biomaterials and biotechnological point of view. We highlight benefits and limitations and we forecast forthcoming alternatives based on novel biomaterials and biotechnology methods. In the first part we expose the physiological and clinical aspects of the disease, focusing on the multiple factors that give origin to the disorder and highlighting the contribution of these factors to the triggering of each step of the disease. Then we analyze available and under development biomaterials-based drug-delivery devices (DDD), taking into account the anatomical and functional characteristics of the healthy and ill retinal tissue.

Effects of Repeated Intravitreal Injections of Dexamethasone Implants on Intraocular Pressure: A 4-Year Study

Purpose

Dexamethasone and other corticosteroids are administered intravitreally to treat a variety of retinal diseases. As a side effect, they can alter intraocular pressure (IOP). The purpose of this study is to describe the incidence, severity, and management of ocular hypertension following the administration of multiple intravitreal injections of dexamethasone implants.

Materials and Methods

A total of 78 eyes of 78 subjects (males 62%; females 38%; mean age 67 ± 13 years SD) received a total of 152 intravitreal injections of 0.7 mg dexamethasone implants over 4 years. Indications included retinal vein occlusion (87%), diabetic macular edema (9%), wet-type age-related macular degeneration (4%). Ocular hypertension was defined as intraocular pressure above 23 mmHg or any pressure increase of 10 mmHg or more from baseline values. IOP was measured by applanation tonometry before the injection (T0), as well as one week (T1), one month (T2), and three months (T3) afterwards.

Results

Five percent (4/78) of subjects developed ocular hypertension after the 1st injection. On the second and third rounds, additional 7.2% (3/42) and 4.2% (1/24) of subjects developed the same side effect. Among the 8 subjects who received a fourth injection, none was found with OHT. Pressure elevations were detected at T2 and T3. In all patients, topical medical therapy was sufficient to lower the IOP below threshold. Mean pressure variations following the first injection as compared to previous recorded values were +0.97 mmHg (T1), +0.92 mmHg (T2), and -0.41 mmHg (T3) (p < 0.05). Mean pressure variations following the second injection were +0.54 mmHg (T1), +0.23 mmHg (T2) and -0.66 mmHg (T3) (p < 0.05).

Conclusion

Ocular hypertension is a recognized side effect of intravitreal dexamethasone. Some patients develop it right after the first injection, while others develop it subsequently, on the 2nd or 3rd round. This side effect becomes most apparent 30-90 days following the implantation procedure and responds well to topical pressure-lowering medications.

A Second Generation Prostanoid Receptor Antagonist Acting at Multiple Receptor Subtypes

It has previously been reported that a prototypical compound (AGN 211377), which blocks pro-inflammatory prostanoid receptors (DP₁, DP₂, EP₁, EP_4, FP, TP) and leaves open IP and EP₂ receptors so that their anti-inflammatory properties could be exerted, produced superior inhibitory effects on cytokine release from human macrophages compared to cyclooxygenase (COX) inhibitors. This favorable activity profile translated into animal studies, with AGN 211377 exceeding the level of inhibition afforded by COX inhibition. AGN 211377 was not, however, a practical drug candidate, having poor bioavailability and cost of goods concerns. Compound 1 (designated AGN 225660) represents a second-generation compound with an entirely different "druggable" core structure. Such a dramatic change in chemical scaffold created uncertainty with respect to matching the effects of AGN 211377. AGN 225660 inhibited RANTES, IL-8, and MCP-1 secretion by at least 50%, from TNFα activated human macrophages. Although AGN 225660 reduced TNFα-evoked MCP-1 release from human monocyte-derived macrophages, it increased LPS-induced MCP-1 secretion (up to 2-fold) from human monocyte-derived dendritic cells. However, AGN 225660 inhibited the release of IL12p 70 and IL-23 from human monocyte-derived dendritic cells stimulated by LPS by more than 70%. This effect of AGN 225660 was reproduced in part by the prototype compound AGN 211377 and a combination of selective DP₁, EP₁, EP₄, FP, and TP antagonists. These findings suggest important effects on T cell skewing and disease modification by this class of therapeutic agents. AGN 225660 exhibited good ocular bioavailability and was active in reducing ocular inflammation associated with phacoemulsification surgery, LPS, and arachidonic acid induced uveitis.

Identifying Specific Combinations of Matrix Properties that Promote Controlled and Sustained Release of a Hydrophobic Drug from Electrospun Meshes

Despite advances in the development of degradable polymers for drug delivery, effective translation of drug-loaded materials is often hindered due to a poor understanding of matrix property combinations that promote controlled and sustained release. In this study, we investigated the influence of dominant factors on the release of a hydrophobic glucocorticoid dexamethasone (DEX) from electrospun meshes. Polycaprolactone meshes released 98% of the drug within 24 h, while poly(l-lactide) meshes exhibited negligible release even after 28 days despite both polymers being slow-degrading. Differences in drug-polymer interactions and drug-polymer miscibility-but neither matrix degradation nor differences in bulk hydrophobicity-influenced DEX release from these semi-crystalline matrices. Poly(d,l-lactide-co-glycolide) 50:50 meshes possessing two different fiber diameters exhibited a sequential burst and sustained release, while poly(d,l-lactide-co-glycolide) 85:15 meshes cumulatively released 26% drug in a controlled manner. Although initial drug release from these matrices was driven by differences in matrix architecture and solid-state drug solubility, release toward the later stages was influenced by a combination of fiber swelling and matrix degradation as evidenced by gross and microstructural changes to the mesh network. We suggest that drug release from polymeric matrices can be better understood via investigation of critical matrix characteristics influencing release, as well as concomitant examination of drug-polymer interactions and miscibility. Our findings offer rational matrix design criteria to achieve controlled/extended drug release for promoting sustained biological responses.

Phase 3, Randomized, 20-Month Study of Bimatoprost Implant in Open-Angle Glaucoma and Ocular Hypertension (ARTEMIS 1)

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of 10- and 15-μg bimatoprost implant in subjects with open-angle glaucoma (OAG) and ocular hypertension (OHT) after initial and repeated administrations.

DESIGN

Randomized, 20-month, multicenter, subject- and efficacy evaluator-masked, parallel-group, phase 3 clinical study.

PARTICIPANTS

Adults with OAG or OHT in each eye, open iridocorneal angle inferiorly in the study eye, and study eye baseline IOP (hour 0; 8 am) of 22-32 mmHg after washout.

METHODS

Study eyes received bimatoprost implant 10 μg (n = 198) or 15 μg (n = 198) on day 1 with readministration at weeks 16 and 32, or twice-daily topical timolol maleate 0.5% (n = 198). Intraocular pressure was measured at hours 0 and 2 at each visit.

MAIN OUTCOME MEASURES

Primary end points were IOP and change from baseline IOP through week 12. Safety measures included treatment-emergent adverse events (TEAEs) and corneal endothelial cell density (CECD).

RESULTS

Both dose strengths of bimatoprost implant were noninferior to timolol in IOP lowering after each administration. Mean diurnal IOP was 24.0, 24.2, and 23.9 mmHg at baseline and from 16.5-17.2, 16.5-17.0, and 17.1-17.5 mmHg through week 12 in the 10-μg implant, 15-μg implant, and timolol groups, respectively. The incidence of corneal and inflammatory TEAEs of interest (e.g., corneal endothelial cell loss, iritis) was higher with bimatoprost implant than timolol and highest with the 15-μg dose strength. Incidence of corneal TEAEs increased after repeated treatment; with 3 administrations at fixed 16-week intervals, incidence of ≥20% CECD loss was 10.2% (10-μg implant) and 21.8% (15-μg implant). Mean best-corrected visual acuity (BCVA) was stable; 3 implant-treated subjects with corneal TEAEs had >2-line BCVA loss at their last visit.

CONCLUSIONS

Both dose strengths of bimatoprost implant met the primary end point of noninferiority to timolol through week 12. One year after 3 administrations, IOP was controlled in most subjects without additional treatment. The risk-benefit assessment favored the 10-μg implant over the 15-μg implant. Ongoing studies are evaluating other administration regimens to reduce the potential for CECD loss. The bimatoprost implant has potential to improve adherence and reduce treatment burden in glaucoma.

[Pharmacological treatment strategies and surgical options for uveitis]

BACKGROUND

Modern treatment of uveitis aims at a complete control of inflammatory activity, preservation of visual function and the prevention of secondary organ damage as a consequence of the underlying inflammatory disease and its treatment.

OBJECTIVE

This article gives an update about the strategies of pharmacological and surgical options for uveitis.

MATERIAL AND METHODS

The outcomes reported here are based on a PubMed search using the terms <"uveitis" AND "therapy"> and <"uveitis" AND "surgery" OR "surgical treatment">. All prospective studies and case series with more than 20 cases as well as review articles from the last 5 years along with cited cross-references were evaluated.

RESULTS

Local and systemic corticosteroids form the foundation of treatment after exclusion of an infectious etiology. If uveitis activity is not controlled within 6 weeks or if the daily corticosteroid dosage is unacceptably high, a treatment escalation using immunomodulatory drugs is required. If a complete control of inflammatory activity is not achieved, in a third phase treatment is supplemented by antibody-based treatment or cytokines, so-called biologics, with the aim of complete long-term freedom from disease without local or systemic steroid treatment. This target is achieved in 65-80% and guarantees long-term functional stability and anatomical integrity. Early treatment escalation in cases of persisting or recurrent activity as a rule prevents new secondary organ damage. Surgical options are utilized for diagnostic purposes, the administration of intravitreal drugs and for treatment of secondary complications.

CONCLUSION

Just like the majority of immunological diseases, uveitis is a chronic disease requiring long-term and possibly lifelong treatment and remission (absence of inflammation without treatment) is achieved in only <20%. Surgical interventions can be performed with a good prognosis, if the optic nerve head and macula are not involved. They have a substantially lower complication rate when freedom from symptoms exists preoperatively for at least 3 months.

Anisotropic poly(lactic-co-glycolic acid) microparticles enable sustained release of a peptide for long-term inhibition of ocular neovascularization

Leading causes of vision loss include neovascular age-related macular degeneration (NVAMD) and macular edema (ME), which both require frequent intravitreal injections for treatment. A safe, poly(lactic-co-glycolic acid) (PLGA)-based biodegradable polymeric microparticle (MP) delivery system was developed that encapsulates and protects a biomimetic peptide from degradation, allows sustained intraocular release through polymer hydrolysis, and demonstrates a prolonged anti-angiogenic effect in vivo in three different NVAMD animal models (a laser-induced choroidal neovascularization mouse model, a rhoVEGF transgenic mouse model, and a Tet/opsin/VEGF transgenic mouse model) following intravitreal administration. The role of copolymer composition and microparticle shape was explored and 85:15 lactide-to-glycolide PLGA formed into ellipsoidal microparticles was found to be effective at inhibiting neovascularization for at least 16 weeks in vivo. Treatments were found to not only inhibit the growth of neovascularization, but also to cause regression of the neovasculature, reduce vascular leakage, and prevent exudative retinal detachment. These particulate devices are promising for the sustained release of biologics in the eye and may be useful for treating retinal diseases. STATEMENT OF SIGNIFICANCE: Devastating retinal diseases cause blindness in millions of people around the world. Current protein-based treatments have insufficient efficacy for many patients and also necessitate frequent intravitreal injections. Here, we demonstrate a new treatment consisting of a peptide encapsulated in biodegradable microparticles. We explore the effects of copolymer composition and physical shape of polymeric microparticles and find that both modulate peptide release. Efficacy of the treatment was validated in three different mouse models and the lead formulation was determined to be effective long-term, for at least 16 weeks in vivo, following a single injection. Treatments inhibited and regressed neovascularization as well as reduced vascular leakage. Anisotropic polymeric microparticles are promising for the sustained release of biologics in the eye.

Intravitreal dexamethasone implant as an alternative to systemic steroids as prophylaxis for uveitic cataract surgery: a randomized trial

PURPOSE

To determine the utility of the dexamethasone implant (IVD) as an alternative to systemic steroids as prophylaxis against cystoid macular edema (CMO) in patients with chronic, recurrent CMO associated intermediate or posterior uveitis (IU/PU), and cataract undergoing cataract surgery.

METHODS

This was a randomized, parallel design, and clinical trial. Patients with IU/PU and cataract scheduled for cataract surgery were randomly assigned to receive the IVD concurrently with cataract surgery (Group 1: 20 patients) or systemic steroids (Group 2: 23 patients) tapered over 4-6 weeks along with uneventful cataract surgery and routine postoperative care. Patients with glaucoma/contraindications to steroids were excluded. All patients were followed up for 6 months.

OUTCOME MEASURE

Primary-incidence of postoperative CMO. Secondary-the change in BCVA (corrected distance visual acuity) and Central Subfield thickness (CST) and complications. Appropriate statistical analysis was done.

RESULTS

The median age was 47.3 ± 4.23 years (group 1) and 49.12 ± 5.32 years (Group 2). One patient (Group 1) and two (Group 2) developed CMO. The BCVA improved significantly in both groups (p = 0.013). The CST change was insignificant. Four patients (Group 1) required intraocular pressure (IOP) lowering medications. Three patients (Group 2) required early steroid taper.

CONCLUSIONS

IVD is a good alternative as prophylaxis in IU/PU and cataract in preventing postoperative CMO.

Pharmaceutical Formulation Methods for Improving Retinal Drug Delivery

Clinical pharmacology training for clinicians typically focuses on a drug's Active Pharmaceutical Ingredient. However, pharmaceutical formulation, the process of optimizing manufacturing methods and excipients to make a final drug product, is a critical process in determining whether a potential drug can become a realistic, routinely used therapeutic agent. This review focuses on the formulation methods used in commonly prescribed retina drug products.

Real-World Assessment of Dexamethasone Intravitreal Implant in DME: Findings of the Prospective, Multicenter REINFORCE Study

BACKGROUND AND OBJECTIVE

Dexamethasone intravitreal implant (DEX) (Ozurdex; Allergan plc, Dublin, Ireland) is approved for the treatment of diabetic macular edema (DME). This study assessed the real-world effectiveness, safety, and reinjection interval of DEX in adult patients with DME.

PATIENTS AND METHODS

This was a phase 4, prospective, multicenter (18 U.S. sites), observational study.

RESULTS

The study population comprised 177 patients (180 eyes; 93.8% previously treated). Baseline mean best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were 54.4 letters and 424.6 μm, respectively. DEX was administered as monotherapy or with other DME therapy (55%/45%). The mean reinjection interval was 5.0 months. Mean maximum BCVA change from baseline after the first three DEX injections was +9.1 letters, +7.7 letters, and +7.0 letters, respectively (P < .001); 36.0% of eyes achieved 15-letter or greater BCVA improvement. Mean maximum CRT change from baseline was -137.7 μm (P < .001).

CONCLUSION

DEX used alone or with other DME therapy improved visual and anatomic outcomes in DME patients in clinical practice, with no new safety concerns. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:425-435.].

Controlled release of corticosteroid with biodegradable nanoparticles for treating experimental autoimmune uveitis

Noninfectious uveitis is a potentially blinding ocular condition that often requires treatment with corticosteroids to prevent inflammation-related ocular complications. Severe forms of uveitis such as panuveitis that affects the whole eye often require a combination of topical and either regional or systemic corticosteroid. Regional corticosteroids are currently delivered inside the eye by intravitreal injection (e.g. Ozurdex®, an intravitreal dexamethasone implant). Intravitreal injection is associated with rare but potentially serious side effects, including endophthalmitis, retinal and vitreous hemorrhage, and retinal detachment. Subconjunctival (SCT) injection is a less invasive option that is a common route used for post-surgical drug administration and treatment of infection and severe inflammation. However, it is the water soluble form of dexamethasone, dexamethasone sodium phosphate (DSP), that has been demonstrated to achieve high intraocular penetration with subconjunctival injection. It is difficult to load highly water soluble drugs, such as DSP, and achieve sustained drug release using conventional encapsulation methods. We found that use of carboxyl-terminated poly(lactic-co-glycolic acid) (PLGA) allowed encapsulation of DSP into biodegradable nanoparticles (NP) with relatively high drug content (6% w/w) if divalent zinc ions were used as an ionic "bridge" between the PLGA and DSP. DSP-Zn-NP had an average diameter of 210 nm, narrow particle size distribution (polydispersity index ~0.1), and near neutral surface charge (-9 mV). DSP-Zn-NP administered by SCT injection provided detectable DSP levels in both the anterior chamber and vitreous chamber of the eye for at least 3 weeks. In a rat model of experimental autoimmune uveitis (EAU), inflammation was significantly reduced in both the front and back of the eye in animals that received a single SCT injection of DSP-Zn-NP as compared to animals that received either aqueous DSP solution or phosphate buffered saline (PBS). DSP-Zn-NP efficacy was evidenced by a reduced clinical disease score, decreased expression of various inflammatory cytokines, and preserved retinal structure and function. Furthermore, SCT DSP-Zn-NP significantly reduced microglia cell density in the retina, a hallmark of EAU in rats. DSP-Zn-NP hold promise as a new strategy to treat noninfectious uveitis and potentially other ocular inflammatory disorders.

Long-term probability of intraocular pressure elevation with the intravitreal dexamethasone implant in the real-world

PURPOSE

To evaluate the long-term cumulative probability of intraocular pressure (IOP) elevation with the intravitreal dexamethasone implant (IDI) when used to treat different indications: diabetic macular edema, uveitis, retinal vein occlusion.

METHODS

705 IDI injections (429 eyes) were assessed and Kaplan-Meier graphs were generated to assess: the probability of different levels of IOP elevation (IOP≥21, ≥25 or ≥35 mmHg), IOP change ≥10 mmHg, initiation of IOP-lowering treatment, glaucoma surgery, IOP change with repeat injections and IOP elevation in eyes with glaucoma and ocular hypertension (OHT).

RESULTS

The cumulative probability of IOP ≥21, ≥25 and ≥35 mmHg was 50%-60%, 25%-30% and 6%-7% at 12-24 months, respectively. The probability of initiating IOP-lowering medication was 31%-54% at 12-24 months. Glaucoma and OHT eyes had a higher probability of mild IOP elevation (≥21 mmHg, 65.1%, 75% and 57.8%, p = 0.01), yet a similar moderate (≥25 mmHg, 22.3%, 28% and 30.2%, p = 0.91) and severe elevation of IOP (≥35 mmHg, 3.7%, 7.1% and 4%, p = 0.71) as normal eyes. Glaucoma surgery was required in only 0.9% cases (4/429). At baseline, 8.8% of the treated eyes had glaucoma, 6.7% OHT and 16.9% were already on IOP-lowering medication.

CONCLUSIONS

In the long-term (24 months), IOP elevation is common, generally mild (30% IOP, ≥25 mmHg) and well-tolerated, resolving with topical treatment (54%) and rarely requiring surgery (0.9%).

Post-marketing surveillance study of the safety of dexamethasone intravitreal implant in patients with retinal vein occlusion or noninfectious posterior segment uveitis

Purpose

To evaluate the long-term safety of dexamethasone intravitreal implant (DEX) in patients treated for macular edema associated with retinal vein occlusion (RVO) or noninfectious posterior segment uveitis (NIPSU) in clinical practice.

Patients and methods

Multicenter (102 sites in France, Germany, Spain, UK), prospective, observational, post-authorization safety study in adult patients treated with DEX. Data collected up to 2 years after enrollment included serious adverse events (SAEs) and adverse events of special interest (AESIs; adverse drug reactions that are considered important risks associated with DEX and listed in the European Union Ozurdex Risk Management Plan).

Results

Overall, 803 patients (652 RVO, 151 NIPSU) received on-study DEX treatment, and 73.1% completed 24 months of follow-up; 72.6% were DEX-naïve. Median number of on-study injections per treated eye was 2 (range, 1–7); median reinjection interval was 27.1 weeks. Nonocular SAEs affected 9.5% of patients; none were considered DEX-related. Ocular SAEs (most common: cataract progression) occurred in 3.2% of treated eyes. SAEs were similar in eyes stratified by previous DEX use and number of on-study DEX injections (≤2 or >2), in both RVO and NIPSU. The most common AESIs were cataract formation and progression (20.0% and 19.2% of treated phakic eyes, n=551), increased intraocular pressure (19.0% of treated eyes), and vitreous hemorrhage (3.3% of treated eyes). Cataract progression was more frequent in baseline phakic eyes that were previously treated with DEX or received >2 on-study DEX injections.

Conclusion

The long-term safety profile of DEX was acceptable. No new safety concerns were identified.

Self-implantable double-layered micro-drug-reservoirs for efficient and controlled ocular drug delivery

Eye diseases and injuries impose a significant clinical problem worldwide. Safe and effective ocular drug delivery is, however, challenging due to the presence of ocular barriers. Here we report a strategy using an eye patch equipped with an array of detachable microneedles. These microneedles can penetrate the ocular surface tissue, and serve as implanted micro-reservoirs for controlled drug delivery. The biphasic drug release kinetics enabled by the double-layered micro-reservoirs largely enhances therapeutic efficacy. Using corneal neovascularization as the disease model, we show that delivery of an anti-angiogenic monoclonal antibody (DC101) by such eye patch produces ~90% reduction of neovascular area. Furthermore, quick release of an anti-inflammatory compound (diclofenac) followed by a sustained release of DC101 provides synergistic therapeutic outcome. The eye patch application is easy and minimally invasive to ensure good patient compliance. Such intraocular drug delivery strategy promises effective home-based treatment of many eye diseases.

Treatment for eye injuries and diseases is most efficient when delivered directly into the eye. Here, the authors developed a patient-friendly eye patch equipped with an array of detachable microneedles, through which drugs can be delivered through the cornea for an extended period of time.

Effect of an Injectable Fluocinolone Acetonide Insert on Recurrence Rates in Chronic Noninfectious Uveitis Affecting the Posterior Segment: Twelve-Month Results

PURPOSE

To assess the safety and efficacy of an intravitreal fluocinolone acetonide (FA) insert to manage inflammation associated with chronic noninfectious posterior uveitis.

DESIGN

Multicenter, randomized, prospective, doubled-masked, sham-controlled, 3-year phase 3 clinical trial.

PARTICIPANTS

One hundred twenty-nine participants with recurrent noninfectious posterior uveitis were assigned randomly to FA insert (n = 87) or sham injection (n = 42). The more severely affected eye in participants with bilateral disease was designated as the study eye.

METHODS

The insert (FA, 0.18 mg) was injected into the vitreous cavity; sham injection mimicked the insert delivery procedure. Ophthalmic examinations, OCT, and ocular tolerability and discomfort assessments were conducted; study visits were on days 7 and 28 and months 2, 3, 6, 9, and 12. Uveitis recurrence was treated as needed. The 6-month recurrence rate was the primary outcome measure.

RESULTS

The 6-month (28% and 91%) and 12-month (38% and 98%) uveitis recurrence rates were significantly lower (P < 0.001) with FA insert vs. sham, respectively. Fewer recurrences per study eye (mean, 0.7 vs. 2.5), lower incidence of 15-letter or more decrease in best-corrected visual acuity (14% vs. 31%), and reduced systemic (19% vs. 40%) and local (7% vs. 62%) uveitis adjunctive treatments were observed with FA insert vs. sham, respectively. The FA insert group showed higher rates of cataract. Intraocular pressure-lowering treatment use was similar between groups. No deaths, treatment-related study discontinuations, or unanticipated safety signals were observed through 12 months.

CONCLUSIONS

Chronic noninfectious posterior uveitis was managed successfully in this study population; FA insert eyes experienced fewer uveitis recurrence episodes, required fewer adjunctive treatments, and demonstrated less visual acuity loss compared with sham eyes. The FA insert treatment group showed higher rates of cataract; delivery by injection was not associated with an increase in ocular adverse events or any other safety measures not typically associated with local steroid use, suggesting the procedure is appropriate for an office setting.

Long-term results of intravitreal bevacizumab and dexamethasone for the treatment of punctate inner choroidopathy associated with choroidal neovascularization: A case series

Introduction

To present a case series of three female patients with punctate inner choroidopathy. We report the outcomes after an essentially long follow-up period of up to 14 years and provide evidence of the effectiveness of intravitreal injections of bevacizumab and dexamethasone 0.7 mg in punctate inner choroidopathy patients with choroidal neovascular membrane formation.

Case series presentation

This is a retrospective case series of three female patients with punctate inner choroidopathy who were treated with intravitreal injections anti-vascular endothelial growth factor agent (bevacizumab, 1.25 mg/0.05 mL). Two patients also received intravitreal dexamethasone 0.7 mg. Once a choroidal neovascular membrane developed, the outcome was poor with a best-corrected visual acuity of 6/60 or counting fingers in the affected eyes. The patients were followed up for 5, 14 and 8 years.

Conclusion

The use of dexamethasone 0.7 mg in punctate inner choroidopathy yielded encouraging results and long periods of stability. When choroidal neovascular membrane complicates the primary disease, the prognosis is unfavourable, especially if the macula integrity has already been considerably affected. On the contrary, aggressive early therapy and continued monthly monitoring can prevent severe fibrosis, as showed in previous reports. Further larger-scale studies are needed to evaluate the efficacy of intravitreal dexamethasone 0.7 mg and bevacizumab as an alternative treatment in non-infectious uveitis.

The effects of repeated Ozurdex injections on ocular hypertension

Purpose

The purpose of this study was to correlate the degree of ocular hypertension with the number of Ozurdex injections.

Methods

Intraocular pressure (IOP) fluctuations for a total of 183 injections were studied over a period of at least 12 months. The main indications for treatment were uveitis, diabetic macular edema, and retinal vein occlusion.

Results

Results of the study demonstrate that repeated Ozurdex injections do not increase the frequency of IOP spikes beyond 30 mmHg. For lower IOPs, however, a positive correlation exists. Furthermore, patients with primary open angle glaucoma and uveitis had the highest IOP response to repeated injections. On average, patients with an IOP of ≥28.6 mmHg received pressure lowering medications, after which their IOP reached a stable level (16.7 mmHg) without the need for additional interventions.

Conclusion

The data support the conclusion that multiple Ozurdex injections does not increase the frequency of IOP spikes beyond 30 mmHg, but patients still must be closely monitored if they have a history of primary open angle glaucoma.

Dexamethasone distribution characteristic following controllable continuous sub-tenon drug delivery in rabbit

Drug delivery systems are required to be safe, minimally invasive and effectively delivery drug to the target tissues. But delivery drugs to the eye has not yet satisfied this need. Here, we focused on examining the distribution of dexamethasone (DEX) in ocular and plasmic samples following controllable continuous sub-Tenon drug delivery (CCSDD) of dexamethasone disodium phosphate (DEXP) in rabbit, and to compare that with two traditional routes: subconjunctival injection and intravenous injection. The DEX concentration was analyzed by Shimadzu LC-MS 2010 system. In CCSDD group, during observed 24 h, the mean DEX level in collected samples from highest to lowest following in order: sclera, cornea, retina/choroid, iris, plasma, aqueous humor, lens and vitreous body. In ocular solid tissue, the DEX level in posterior segment is higher than in anatomic corresponding anterior segment, but it is opposite in ocular fluid tissue. High levels of DEX were maintained at 12 h in the ocular tissue immediately after the administration. Even at 24 h, the mean DEX concentration was 31.72 ng/ml and 22.40 ng/ml in aqueous and vitreous, respectively. In CCSDD group, the ocular DEX exposure (AUC0-24) is much higher and plasma exposure is much less than IV group, and it is also similar in SC group except iris. The amount of DEX levels are markedly increased in ocular tissues but it yield lower plasma levels indicating reduction of systemic absorption by CCSDD. Thus, CCSDD is an effective method of delivering DEX into anterior and posterior segment of the eye.

Bimatoprost Sustained-Release Implants for Glaucoma Therapy: 6-Month Results From a Phase I/II Clinical Trial

PURPOSE

To evaluate the safety and intraocular pressure (IOP)-lowering effect of a biodegradable bimatoprost sustained-release implant (Bimatoprost SR).

DESIGN

Phase I/II, prospective, 24-month, dose-ranging, paired-eye controlled clinical trial.

METHODS

At baseline following washout, open-angle glaucoma patients (n = 75) were administered Bimatoprost SR (6 μg, 10 μg, 15 μg, or 20 μg) intracamerally in the study eye; the fellow eye began topical bimatoprost 0.03% once daily. Rescue topical IOP-lowering medication or a single repeat treatment with implant was allowed. The primary endpoint was IOP change from baseline. The main safety measure was adverse events. Results through month 6 are reported.

RESULTS

Bimatoprost SR provided rapid, sustained IOP lowering. Overall mean IOP reduction from baseline through week 16 in study eyes was 7.2, 7.4, 8.1, and 9.5 mm Hg with the 6-μg, 10-μg, 15-μg, and 20-μg dose strengths of implant, respectively, vs 8.4 mm Hg in topical bimatoprost-treated pooled fellow eyes (data censored at rescue/retreatment). Rescue/retreatment was not required in 91% and 71% of study eyes up to week 16 and month 6, respectively. Adverse events in study eyes usually occurred within 2 days after the injection procedure and were transient. Conjunctival hyperemia with onset later than 2 days after the injection procedure was more common with topical bimatoprost than Bimatoprost SR (17.3% vs 6.7% of eyes).

CONCLUSIONS

Bimatoprost SR demonstrated favorable efficacy and safety through 6 months. All dose strengths were comparable to topical bimatoprost in overall IOP reduction through week 16. A single administration controlled IOP in the majority of patients for up to 6 months.

Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review we demonstrate that such compositional simplifications are meaningful when it comes to the design of a solution for osteomyelitis, a disease that is in its natural, non-postoperative form particularly prevalent in the underdeveloped parts of the world wherein poverty, poor sanitary conditions, and chronically compromised defense lines of the immune system are the norm. We show that calcium phosphate nanoparticles, which are inexpensive to make, could be chemically designed to possess the same functionality as a hypothetic mixture additionally composed of: (a) a bone growth factor; (b) an antibiotic for prophylactic or anti-infective purposes; (c) a bisphosphonate as an antiresorptive compound; (d) a viral vector to enable the intracellular delivery of therapeutics; (e) a luminescent dye; (f) a radiographic component; (g) an imaging contrast agent; (h) a magnetic domain; and (i) polymers as viscous components enabling the injectability of the material and acting as carriers for the sustained release of a drug. In particular, calcium phosphates could: (a) produce tunable drug release profiles; (b) take the form of viscous and injectable, self-setting pastes; (c) be naturally osteo-inductive and inhibitory for osteoclastogenesis; (d) intracellularly deliver bioactive compounds; (e) accommodate an array of functional ions; (f) be processed into macroporous constructs for tissue engineering; and (g) be naturally antimicrobial. All in all, we see in calcium phosphates the presence of a protean nature whose therapeutic potentials have been barely tapped into.

Retinal vein occlusion and the use of a dexamethasone intravitreal implant (Ozurdex®) in its treatment

Purpose

To review published data pertaining to the clinical experience with a dexamethasone intravitreal implant (Ozurdex®) with a view to establishing a clinically based therapeutic regime.

Methods

A PubMed search using the MeSH terms “retinal vein occlusion” and either “pathophysiology” or “dexamethasone intravitreal implant” was undertaken for manuscripts published until August 2015. The analysis included studies involving minimally 15 patients under a prospective design or 30 under a retrospective design, a minimal follow up of 6 months, and at least 2 intravitreal Ozurdex® injections per eye.

Results

In the vast majority of eyes, satisfactory outcomes were achieved with retreatment intervals of between 3 and 5 months. Initial evidence indicates a similar efficacy compared to anti-VEGF therapies as a first-line treatment. Safety concerns associated with the long-term and repeated use of Ozurdex® are not borne out by clinical findings: its implantation is not associated with a sustained increase in intraocular pressure (IOP) over time or with the number of applications.

Conclusion

Compared with anti-VEGF therapies, the burden of retreatment is reduced. In patients with chronic macular edema not responsive to repetitive anti-VEGF therapies, the outcome after dexamethasone implant treatment is encouraging. However, these results are achieved at the expense of side effects typically associated with steroids: in up to 20 % of the Ozurdex®-treated patients, an elevation in IOP, which could be medically controlled in the majority of cases, and cataract formation or progression was observed.