New Drugs and New Posterior Delivery Methods in CME

Advanced drug delivery strategies for diabetic retinopathy: current therapeutic advancement, and delivery methods overcoming barriers, and experimental modalities

INTRODUCTION

Diabetic retinopathy, a significant trigger for blindness among working age individuals with diabetes, poses a substantial global health challenge. Understanding its underlying mechanisms is pivotal for developing effective treatments. Current treatment options, such as anti-VEGF agents, corticosteroids, laser photocoagulation, and vitreous surgery, have their limitations, prompting the exploration of innovative approaches like nanocapsules based drug-delivery systems. Nanoparticles provide promising solutions to improve drug delivery in ocular medicine, overcoming the complexities of ocular anatomy and existing treatment constraints.

AREAS COVERED

This review explored advanced therapeutic strategies for diabetic retinopathy, focusing on current medications with their limitations, drug delivery methods, device innovations, and overcoming associated barriers. Through comprehensive review, it aimed to contribute to the discovery of more efficient management strategies for diabetic retinopathy in the future.

EXPERT OPINION

In the next five to ten years, we expect a revolutionary shift in how diabetic retinopathy is treated. As we deepen our understanding of oxidative stress and metabolic dysfunction, antioxidants with specialised delivery matrices are poised to take center stage in prevention and treatment strategies. Our vision is to create a more integrated approach to diabetic retinopathy management that not only improves patient outcomes but also reduces the risks associated to traditional therapies.

SUSTAINED-RELEASE LOW-DOSE FLUOCINOLONE ACETONIDE INTRAVITREAL IMPLANT FOR CHRONIC POSTOPERATIVE CYSTOID MACULAR EDEMA: TWO CASE REPORTS

BACKGROUND/PURPOSE

To describe two cases of patients diagnosed with chronic postoperative cystoid macular edema associated with noninfectious posterior uveitis who had limited treatment response to previous corticosteroid modalities and then received a single intravitreal fluocinolone 0.18-mg implant. Chronic postoperative cystoid macular edema (CME) may occur after intraocular surgery and is a common cause of postoperative visual loss. Sometimes called Irvine-Gass syndrome or persistent pseudophakic CME, chronic postoperative CME complicates roughly 0.1% to 2.0% of low-risk, small-incision phacoemulsification surgeries. There are a number of conventional approaches to chronic postoperative CME management, including topical corticosteroids with or without nonsteroidal anti-inflammatory drugs, intravitreal corticosteroid injections, and vascular endothelial growth factor (VEGF) inhibitor injections, but these options have several limitations. A major shortcoming of conventional formulations of anti-inflammatory therapies for chronic postoperative CME (i.e., topical drops, intraocular, and periocular injections) is the need for repeated dosing in chronic cases, which is expensive and burdensome to patients.

METHODS

Series of two case reports. Patient 1, a 75-year-old Latina woman, presented with a history of longstanding, recurrent inflammation after cataract extraction and subsequent vitreoretinal surgeries. Patient 2, an 85-year-old white woman, presented with acute blurred vision, swelling, and pain 5 years after cataract surgery and laser peripheral iridotomy. Both were diagnosed with chronic postoperative CME and ultimately treated with the 3-year sustained-release fluocinolone acetonide intravitreal implant (FAi) 0.18 mg.

RESULTS

Compared with baseline, both patients experienced resolution of their disease symptoms, >3 lines of visual acuity improvement, and macular edema reduction of 56.2% and 38.4% at 15 and 6 months, respectively, after the fluocinolone implant. No steroid related adverse events including any intraocular pressure measurement >25 mmHg were observed.

CONCLUSION

A single intravitreal fluocinolone 0.18-mg implant can effectively and safely treat vision loss and increased central macular thickness because of chronic postoperative cystoid macular edema associated with noninfectious posterior uveitis. The FAi 0.18 mg provides a safe, long-acting, low-dose anti-inflammatory treatment in patients with noninfectious posterior-segment inflammation associated with chronic postoperative CME.

Pathogenesis and current therapies for non-infectious uveitis

Non-infectious uveitis (NIU) is a disorder with various etiologies and is characterized by eye inflammation, mainly affecting people of working age. An accurate diagnosis of NIU is crucial for appropriate therapy. The aim of therapy is to improve vision, relieve ocular inflammation, prevent relapse, and avoid treatment side effects. At present, corticosteroids are the mainstay of topical or systemic therapy. However, repeated injections are required for the treatment of chronic NIU. Recently, new drug delivery systems that may ensure intraocular delivery of therapeutic drug levels have been highlighted. Furthermore, with the development of immunosuppressants and biologics, specific therapies can be selected based on the needs of each patient. Immunosuppressants used in the treatment of NIU include calcineurin inhibitors and antimetabolites. However, systemic immunosuppressive therapy itself is associated with adverse effects due to the inhibition of immune function. In patients with refractory NIU or those who cannot tolerate corticosteroids and immunosuppressors, biologics have emerged as alternative treatments. Thus, to improve the prognosis of patients with NIU, NIU should be managed with different drugs according to the response to treatment and possible side effects.

Intravitreal Fluocinolone Acetonide Implant (ILUVIEN®) for the Treatment of Retinal Conditions. A Review of Clinical Studies

Fluocinolone acetonide (FAc) intravitreal implant (Iluvien®) is a corticosteroid implant indicated for the treatment of diabetic macular oedema (DMO) in patients who have previously received conventional treatment without good response, non-infectious posterior uveitis, and as an off-label treatment of the macular oedema secondary to retinal vein occlusion. FAc is a non-biodegradable 0.19 mg intravitreal implant which is designed to release FAc over 3 years at a rate of approximately 0.2 mcg per day. The aim of this review is to describe the special pharmacological properties of Iluvien and display the outcomes of the most important clinical trials and real-world studies regarding its efficacy and safety for the management of the above retinal disorders.

Intravitreal fluocinolone acetonide 0.19 mg (Iluvien®) for the treatment of uveitic macular edema: 2-year follow-up of 20 patients

PURPOSE

To evaluate intravitreal 0.19 mg fluocinolone acetonide implant (FAi) (Iluvien®) for the treatment of chronic non-infectious uveitis with associated cystoid macular edema (CME).

METHODS

A retrospective review of medical reports from a single Danish tertiary centre including 20 patients (20 eyes), treated with 0.19 mg FAi for non-infectious uveitic CME. The primary endpoints were change in best corrected visual acuity (BCVA) and central retinal thickness (CRT). The secondary endpoints were recurrence rate, change in systemic treatment, and intraocular pressure (IOP).

RESULTS

Mean follow-up of the 20 eyes was 2.3 ± 1.1 years. BCVA improved at 6 (p = 0.13), 12 (p = 0.05), 18 (p = 0.03), and 24 months and CRT decreased at 6 (p = 0.004), 12 (p = 0.006), 18, and 24 months after 0.19 mg FAi. Within 18 months after implantation, four of 14 patients (28.6%) relapsed. Three of five patients discontinued systemic corticosteroids within 4 months and one patient continued with reduced dose. Five of 10 patients receiving disease-modifying antirheumatic drugs (DMARDs) at time of implantation discontinued within 1 year. No patients started new systemic treatment. Eight eyes were treated with topical IOP-lowering medication at the time of implantation, of these two later underwent trabeculectomy. There were no complications associated with previous glaucoma surgery.

CONCLUSION

This long-term follow-up study showed that intravitreal treatment with 0.19 mg FAi should be considered in the treatment of chronic non-infectious uveitic CME in selected patients. This treatment is safe even in selected glaucoma patients and may offer reduction or cessation of local or systemic anti-inflammatory treatment.

Fluocinolone Acetonide 0.19 mg Implant in Patients with Cystoid Macular Edema Due To Irvine-Gass Syndrome

Background

Cystoid macular edema (CME) due to Irvine–Gass syndrome (IGS) is one of the common causes of painless visual impairment post-cataract extraction. The treatment of recurrent cases remains unstandardized.

Objective

To evaluate the effectiveness and safety of fluocinolone acetonide intravitreal implant (0.2 µg/day; ILUVIEN^®) in the off-label treatment of recurrent CME due to IGS.

Methods

Retrospective 36-month case series in the Ophthalmology Department of Centro Hospitalar Universitário do Porto, Portugal. Consecutive eyes of patients with recurrent cystoid macular edema due to Irvine–Gass syndrome who underwent a single intravitreal injection of fluocinolone acetonide intravitreal implant were included. Best-corrected visual acuity (logMAR), central macular thickness (µm) and safety (intraocular pressure, mmHg) at baseline and at 6, 12, 24 and 36 months post-administration of the fluocinolone acetonide intravitreal implant were recorded.

Results

Five eyes from three patients were included. The duration of cystoid macular edema was 67.8±25.9 months and all five eyes received more than 2 intravitreal injections of a corticosteroid (triamcinolone and/or dexamethasone implant) prior to fluocinolone acetonide intravitreal implantation. At baseline (median – interquartile range), best-corrected visual acuity was 0.3–0.3; central macular thickness was 492.0–38.0; and intraocular pressure was 16.0–0. By Month 36, best-corrected visual acuity was 0.4 −0.3; central macular thickness was reduced to 369.0–324.0 and intraocular pressure was 17.0–3.0. Four of five eyes had increased intraocular pressure and were managed with intraocular pressure-lowering eye drops.

Conclusion

We report improved functional and anatomical outcomes after treatment with fluocinolone acetonide intravitreal implant, indicating its use as a therapeutic alternative in recurrent cases of cystoid macular edema due to Irvine–Gass syndrome. Additionally, in eyes with suboptimal response to intravitreal therapies, fluocinolone acetonide intravitreal implant may provide longer recurrence-free periods with reduced treatment burden.

Efficacy and Safety of Corticosteroid Implants in Non-infectious Uveitis: A Systematic Review with Network Meta-analysis

BACKGROUND/AIMS

To compare different existent implants for noninfectious uveitis.

METHODS

We performed a systematic review of randomized clinical trials (RCTs), searching in five electronic databases and screening reference lists of included studies and relevant reviews. We performed network meta-analysis to compare 0.18 mg fluocinolone acetonide implants, 0.70 mg and 0.35 mg dexamethasone implants, and sham procedures.

RESULTS

Eight RCTs were included in this systematic review, of which three articles from two studies (n = 358 patients) were included in network meta-analysis. The 0.70 mg dexamethasone implant (at 1.5 months) was associated with better results than the 0.18 mg fluocinolone acetonide implant (at 1 month) at improving vitreous haze grading (RR = 2.96; 95%CI = 1.23-7.07), and with less frequently development of cataracts at 12 (RR = 0.36; 95%CI = 0.17; 0.79) and 36 months (RR = 0.37; 95%CI = 0.20; 0.71).

CONCLUSIONS

In the short term, the 0.70 mg dexamethasone implant is superior at improving vitreous haze, and shows lower risk of cataracts. However, additional RCTs with standardized outcomes are needed.

Regulation of the Ocular Cell/Tissue Response by Implantable Biomaterials and Drug Delivery Systems

Therapeutic advancements in the treatment of various ocular diseases is often linked to the development of efficient drug delivery systems (DDSs), which would allow a sustained release while maintaining therapeutic drug levels in the target tissues. In this way, ocular tissue/cell response can be properly modulated and designed in order to produce a therapeutic effect. An ideal ocular DDS should encapsulate and release the appropriate drug concentration to the target tissue (therapeutic but non-toxic level) while preserving drug functionality. Furthermore, a constant release is usually preferred, keeping the initial burst to a minimum. Different materials are used, modified, and combined in order to achieve a sustained drug release in both the anterior and posterior segments of the eye. After giving a picture of the different strategies adopted for ocular drug release, this review article provides an overview of the biomaterials that are used as drug carriers in the eye, including micro- and nanospheres, liposomes, hydrogels, and multi-material implants; the advantages and limitations of these DDSs are discussed in reference to the major ocular applications.

Morphological and Functional Outcomes after Intravitreal Dexamethasone Injection for Macular Edema in Patients with Central Vein Occlusion at 48-Week Follow-Up

Purpose

The purpose of the study was to assess the efficacy of intravitreal dexamethasone implant (IDI: Ozurdex®) injection in eyes with macular edema due to retinal vein occlusion. Material and Method. A retrospective, nonrandomized study was conducted in patients with macular edema (ME) due to retinal vein occlusion (RVO) who undertook intravitreal Ozurdex® as first-line treatment. We performed a complete ocular exam including macular OCT.

Results

The mean BCVA (logMar) improved from 0.420.42 ± 0.23 logMar at baseline to 0.21 ± 0.23 logMar at 48 weeks in the BRVO group and from 0.72 ± 0.16 logMar at baseline to 0.31 ± 0.23 logMar at 48 weeks in the CRVO group. In both groups, CFT values decreased significantly compared to baseline (p < 0.0001 at each timepoint). Reinjection for recurrent macular edema after 18 weeks was indicated in five eyes (41.67%) in the BRVO group and in six eyes (25%) in the CRVO group. Cataract developed in two eyes (16.67%) in the BRVO group and in one eye (4.17%) in the CRVO group. The IOP was higher than 25 mmHg in two cases in the BRVO group (16.66%) and in three cases (8.33%) in the CRVO group.

Conclusion

Ozurdex® injected intravitreally significantly improved the mean CFT and BCVA in eyes with macular edema due to retinal vein occlusion.

Perioperative Management of Uveitic Cataracts

Uveitis patients represent a unique subset of the population undergoing cataract surgery and pose several challenges that require special consideration and strategy. Maintenance of disease quiescence for at least three months prior to surgery maximizes postoperative outcomes, though these patients remain at increased risk for pseudophakic cystoid macular edema, which can be refractory to the traditional steroid treatments. In this review, we detail the pillars of preoperative optimization, intraoperative considerations, and postoperative management of uveitic cataracts, with special attention on the evidence surrounding prevention and treatment of refractory postoperative cystoid macular edema.

Intravitreal fluocinolone acetonide implant (ILUVIEN®) for diabetic macular oedema: a literature review

Diabetic macular oedema (DMO) is a common complication of diabetic retinopathy and may lead to severe visual loss. In this review, we describe the pathophysiology of DMO and review current therapeutic options such as macular laser photocoagulation, anti-vascular endothelial growth factor agents, and steroid implants with a focus on the new fluocinolone acetonide implant, ILUVIEN®. The results of the Fluocinolone Acetonide in Diabetic Macular Edema (FAME) studies are also presented together with the results of real-world studies to support the clinical use of ILUVIEN® in achieving efficient resolution of DMO and improving vision and macular anatomy in this challenging group of patients.