ILUVIEN® technology in the treatment of center-involving diabetic macular edema: a review of the literature

Long-Term Treatment Outcomes with a Single 0.19 Mg Fluocinolone Acetonide Implant in Non-Infectious Uveitis - A Real-World Study

PURPOSE

To evaluate time to first additional treatment following intravitreal 0.19 mg fluocinolone acetonide (FAc) in non-infectious uveitis with posterior segment involvement (NIU-PS) in a real-world setting.

METHODS

Prospective observational study on 37 eyes (30 patients) with chronic or recurrent NIU-PS, treated with FAc after achieving control - indicated by absence of vitreous haze or clearly visible posterior pole. Over a median follow-up of 48.0 ± 0.0 months, we assessed time to and number of additional treatments, inflammatory activity, central subfield macular thickness (CSMT), visual acuity (VA) and intraocular pressure (IOP).

RESULTS

Restricted mean time to first adjuvant treatment was 31.9 ± 2.97 months, with 52.8% requiring no additional treatment ≥ 48 months. VA remained stable (baseline 0.56 ± 0.44 logMAR, p = 0.86). A negative correlation was found between the number of prior steroid implants (DEX-I) and time to additional treatment (r = -0.44, p = 0.001). For up to 24 months, FAc reduced anterior chamber flare (0.44 ± 0.81 to 0.00 ± 0.00, p < 0.001), vitreous haze (0.28 ± 0.51 to 0.00 ± 0.00, p = 0.01), and CSMT (407.1 ± 135.9 µm at baseline to 324.2 ± 75.7 µm at M24, p = 0.001). Within 48 months, ocular hypertension (≥25 mmHg) occurred in 22.2% of eyes (8/36), with 19.4% (7/36) requiring new-onset IOP-lowering drops.

CONCLUSION

FAc demonstrated efficacy in managing low-grade NIU-PS, reducing the need for additional treatments and controlling intraocular inflammation for an average of 32 months.

Real-World Evidence of the Long-Term Effectiveness of 0.2 μg/Day Fluocinolone Acetonide Implant in Persistent and Recurrent Diabetic Macular Edema - A Single Center Study

Purpose

To report the long-term functional, anatomical and safety outcomes of 0.2 μg/day fluocinolone acetonide 0.19mg in patients with persistent or recurrent diabetic macular edema (DME).

Methods

Retrospective, observational, single-center study of patients with recurrent or persistent DME. All patients received 0.2 μg/day of fluocinolone acetonide 0.19mg, and data were collected at baseline and months 1, 3, 6, 12, 24 and 36 after implantation. Outcomes measured included best-corrected visual acuity (BCVA), central macular thickness (CMT), intraocular pressure (IOP), and safety outcomes.

Results

A total of 28 eyes from 28 patients were included. The mean age was 66.5 years (95% CI 62.8-70.2) with a mean duration of DME of 8.8 years (95% CI 7.7-10.0). Only two eyes were phakic. Mean follow-up was 25.4 months (95% CI 21.2-29.6). Mean BCVA at baseline was 48.6 ETDRS letters (95% CI 41.3-55.8) and improved as early as month 1 of follow-up with a mean gain in BCVA of 7.8 (95% CI 4.3-11.3) ETDRS letters (p<0.001). Statistically significant improvements in BCVA were also observed at months 6, 12 and 24. At baseline, patients had a mean CMT of 530.5µm (95% CI 463.0-598.0), and a decrease in CMT was observed, starting at the first month of follow-up (mean CMT reduction of -170.5µm, 95% CI -223.8- -117.1; p<0.001). Statistically significant decreases in CMT were also observed at months 6, 12, 24, and 36, with the maximum decrease observed at month 12 (p<0.001). Mean IOP at baseline was 16.4mmHg (95% CI 15.3-17.5) and nine eyes (32.1%) had an IOP ≥21mmHg during follow-up.

Conclusion

Our results support the effectiveness and safety profile of fluocinolone acetonide. Although additional long-term real-world evidence is required, fluocinolone acetonide may represent a safe strategy for daily, low-dose, sustained and localized release to the posterior segment of the eye, providing both functional and anatomical benefits in DME.

The Use of Polymer Blends in the Treatment of Ocular Diseases

The eye is an organ with limited drug access due to its anatomical and physiological barriers, and the usual forms of ocular administration are limited in terms of drug penetration, residence time, and bioavailability, as well as low patient compliance. Hence, therapeutic innovations in new drug delivery systems (DDS) have been widely explored since they show numerous advantages over conventional methods, besides delivering the content to the eye without interfering with its normal functioning. Polymers are usually used in DDS and many of them are applicable to ophthalmic use, especially biodegradable ones. Even so, it can be a hard task to find a singular polymer with all the desirable properties to deliver the best performance, and combining two or more polymers in a blend has proven to be more convenient, efficient, and cost-effective. This review was carried out to assess the use of polymer blends as DDS. The search conducted in the databases of Pubmed and Scopus for specific terms revealed that although the physical combination of polymers is largely applied, the term polymer blend still has low compliance.

A novel, minimally invasive implant to assist in repeated intraocular drug delivery

The standard of care for posterior segment disorders such as wet age-related macular degeneration, diabetic macular oedema and retinal vascular occlusions is pharmacotherapy by intravitreal drug delivery. Since the therapeutic effect of these drugs lasts only around 4 to 8 weeks, repeated intravitreal injections are required. Pain is experienced by the patients during injection as the needle courses through the sclera and choroid. The current work describes the design and development of a novel anodized titanium alloy implant that allows for intravitreal injections through the implant so that the needle transverses only the conjunctiva, thus minimizing discomfort to the patient. Both ex-vivo testing of the implant in enucleated goat's eye as well as in-vivo validation in rabbit eyes was carried out. The implant was placed through pars plana via a minor surgical procedure and was sutured to the sclera and covered with conjunctiva. Subsequent intravitreal injections were administered under topical anaesthesia with a 30-gauge needle through the implant thus delivering the drug into the vitreous cavity. Repeated intravitreal injections were administered every 2 weeks via the implant for 3 months in 4 rabbits. Apart from cataract in 1 rabbit, no complications were observed. There was no evidence of intra-ocular inflammation or infection at final follow-up. Histopathological analysis did not reveal any inflammation or necrosis around the area of implant. The implants were subsequently removed at 5 months and scleral wound was closed with a single suture. The sclera and overlying conjunctiva healed well and no intraocular complications were observed after removal.

Considerations for Polymers Used in Ocular Drug Delivery

PURPOSE

Age-related eye diseases are becoming more prevalent. A notable increase has been seen in the most common causes including glaucoma, age-related macular degeneration (AMD), and cataract. Current clinical treatments vary from tissue replacement with polymers to topical eye drops and intravitreal injections. Research and development efforts have increased using polymers for sustained release to the eye to overcome treatment challenges, showing promise in improving drug release and delivery, patient experience, and treatment compliance. Polymers provide unique properties that allow for specific engineered devices to provide improved treatment options. Recent work has shown the utilization of synthetic and biopolymer derived biomaterials in various forms, with this review containing a focus on polymers Food and Drug Administration (FDA) approved for ocular use.

METHODS

This provides an overview of some prevalent synthetic polymers and biopolymers used in ocular delivery and their benefits, brief discussion of the various types and synthesis methods used, and administration techniques. Polymers approved by the FDA for different applications in the eye are listed and compared to new polymers being explored in the literature. This article summarizes research findings using polymers for ocular drug delivery from various stages: laboratory, preclinical studies, clinical trials, and currently approved. This review also focuses on some of the challenges to bringing these new innovations to the clinic, including limited selection of approved polymers.

RESULTS

Polymers help improve drug delivery by increasing solubility, controlling pharmacokinetics, and extending release. Several polymer classes including synthetic, biopolymer, and combinations were discussed along with the benefits and challenges of each class. The ways both polymer synthesis and processing techniques can influence drug release in the eye were discussed.

CONCLUSION

The use of biomaterials, specifically polymers, is a well-studied field for drug delivery, and polymers have been used as implants in the eye for over 75 years. Promising new ocular drug delivery systems are emerging using polymers an innovative option for treating ocular diseases because of their tunable properties. This review touches on important considerations and challenges of using polymers for sustained ocular drug delivery with the goal translating research to the clinic.

Polymeric Implants for the Treatment of Intraocular Eye Diseases: Trends in Biodegradable and Non-Biodegradable Materials

Intraocular/Intravitreal implants constitute a relatively new method to treat eye diseases successfully due to the possibility of releasing drugs in a controlled and prolonged way. This particularity has made this kind of method preferred over other methods such as intravitreal injections or eye drops. However, there are some risks and complications associated with the use of eye implants, the body response being the most important. Therefore, material selection is a crucial factor to be considered for patient care since implant acceptance is closely related to the physical and chemical properties of the material from which the device is made. In this regard, there are two major categories of materials used in the development of eye implants: non-biodegradables and biodegradables. Although non-biodegradable implants are able to work as drug reservoirs, their surgical requirements make them uncomfortable and invasive for the patient and may put the eyeball at risk. Therefore, it would be expected that the human body responds better when treated with biodegradable implants due to their inherent nature and fewer surgical concerns. Thus, this review provides a summary and discussion of the most common non-biodegradable and biodegradable materials employed for the development of experimental and commercially available ocular delivery implants.

Intravitreal Therapy for Diabetic Macular Edema: An Update

Diabetic macular edema (DME) represents a prevalent and disabling eye condition. Despite that DME represents a sight-threatening condition, it is also among the most accessible to treatment. Many different treatment options including photocoagulation, intravitreal medical treatment (either vascular endothelial growth factor inhibitors or corticosteroids therapies), and surgical removal are currently available. Although laser has been considered as the gold standard for many years, over the past several years vascular endothelial growth factor inhibitors (anti-VEGFs) have become first-line therapy. However, many patients do not adequately respond to them. With the development of sustained-release corticosteroid devices, steroids have gained a presence in the management of the DME. We review and update the role of anti-VEGF and intravitreal sustained-release corticosteroid management of DME. According to the currently available scientific evidence, the choice of one anti-VEGF over another critically depends on the baseline best-corrected visual acuity (BCVA). While aflibercept may be the drug of choice in low baseline BCVA, the three anti-VEGFs (bevacizumab, ranibizumab, and aflibercept) provided similar functional outcomes when the baseline BCVA was higher. DEX implants are a valuable option for treating DME, although they are usually seen as a second choice, particularly in those eyes that have an insufficient response to anti-VEGF. The new evidence suggested that, in eyes that did not adequately respond to anti-VEGF, switching to a DEX implant at the time to 3 monthly anti-VEGF injections provided better functional outcomes.

Real-World Efficacy and Safety of Fluocinolone Acetonide Implant for Diabetic Macular Edema: A Systematic Review

To assess real-world outcomes of fluocinolone acetonide (FAc) implant in treating diabetic macular edema (DME), a systematic literature review was conducted on PubMed in order to identify publications assessing the efficacy and safety of the FAc implant in DME in daily practice. Case reports and randomized controlled trials were excluded. Twenty-two observational real-world studies analyzing a total of 1880 eyes were included. Mean peak visual gain was +8.7 letters (11.3 months post-FAc injection) and was greater for lower baseline best corrected visual acuity (BCVA) and for more recent DME. Mean central retinal thickness (CRT) decreased 34.3% from baseline. 77.0% of the analyzed studies reported both BCVA improvement of at least five letters and a CRT decrease by 20% or more. Rescue therapy was needed more frequently when FAc was administered for chronic DME. FAc-induced ocular hypertension was reported in 20.1% of patients but only 0.6% needed surgery. Cataract extraction was performed in 43.2% of phakic patients. Adequate patient selection is essential for optimal FAc response and better safety profile. Currently positioned as second- or third-line treatment in the management algorithm, FAc implant decreases treatment burden and provides better letter gain when administered for more recent DME.

The Evolving Treatment of Diabetic Retinopathy

Purpose

To review the current therapeutic options for the management of diabetic retinopathy (DR) and diabetic macular edema (DME) and examine the evidence for integration of laser and pharmacotherapy.

Methods

A review of the PubMed database was performed using the search terms diabetic retinopathy, diabetic macular edema, neovascularization, laser photocoagulation, intravitreal injection, vascular endothelial growth factor (VEGF), vitrectomy, pars plana vitreous surgery, antiangiogenic therapy. With additional cross-referencing, this yielded 835 publications of which 301 were selected based on content and relevance.

Results

Many recent studies have evaluated the pharmacological, laser and surgical therapeutic strategies for the treatment and prevention of DR and DME. Several newer diagnostic systems such as optical coherence tomography (OCT), microperimetry, and multifocal electroretinography (mfERG) are also assisting in further refinements in the staging and classification of DR and DME. Pharmacological therapies for both DR and DME include both systemic and ocular agents. Systemic agents that promote intensive glycemic control, control of dyslipidemia and antagonists of the renin-angiotensin system demonstrate beneficial effects for both DR and DME. Ocular therapies include anti-VEGF agents, corticosteroids and nonsteroidal anti-inflammatory drugs. Laser therapy, both as panretinal and focal or grid applications continue to be employed in management of DR and DME. Refinements in laser devices have yielded more tissue-sparing (subthreshold) modes in which many of the benefits of conventional continuous wave (CW) lasers can be obtained without the adverse side effects. Recent attempts to lessen the burden of anti-VEGF injections by integrating laser therapy have met with mixed results. Increasingly, vitreoretinal surgical techniques are employed for less advanced stages of DR and DME. The development and use of smaller gauge instrumentation and advanced anesthesia agents have been associated with a trend toward earlier surgical intervention for diabetic retinopathy. Several novel drug delivery strategies are currently being examined with the goal of decreasing the therapeutic burden of monthly intravitreal injections. These fall into one of the five categories: non-biodegradable polymeric drug delivery systems, biodegradable polymeric drug delivery systems, nanoparticle-based drug delivery systems, ocular injection devices and with sustained release refillable devices. At present, there remains no one single strategy for the management of the particular stages of DR and DME as there are many options that have not been rigorously tested through large, randomized, controlled clinical trials.

Conclusion

Pharmacotherapy, both ocular and systemic, will be the primary mode of intervention in the management of DR and DME in many cases when cost and treatment burden are less constrained. Conventional laser therapy has become a secondary intervention in these instances, but remains a first-line option when cost and treatment burden are more constrained. Results with subthreshold laser appear promising but will require more rigorous study to establish its role as adjunctive therapy. Evidence to support an optimal integration of the various treatment options is lacking. Central to the widespread adoption of any therapeutic regimen for DR and DME is substantiation of safety, efficacy, and cost-effectiveness by a body of sound clinical trials.

N6-Methyladenosine METTL3 Modulates the Proliferation and Apoptosis of Lens Epithelial Cells in Diabetic Cataract

N⁶-methyladenosine (m⁶A) is the most prevalent eukaryotic messenger RNA modification. Diabetic cataract (DC) is caused by high glucose (HG) in diabetes mellitus. However, the regulatory mechanism of m⁶A in the DC pathogenesis is poorly understood. In present research, we performed the m⁶A-RNA immunoprecipitation sequencing (MeRIP-Seq) analysis and detected the m⁶A modification profile in the HG- or normal glucose (NG)-induced human lens epithelial cells (HLECs). Results revealed that methyltransferase-like 3 (METTL3) was upregulated in the DC tissue specimens and HG-induced HLECs. Besides, total m⁶A modification level was higher in the HG-induced HLECs. Functionally, METTL3 knockdown promoted the proliferation and repressed the apoptosis of HLECs induced by HG. MeRIP-Seq analysis revealed that ICAM-1 might act as the target of METTL3. Mechanistically, METTL3 targets the 3′ UTR of ICAM-1 to stabilize mRNA stability. In conclusion, this research identified the regulation of METTL3 in the HG-induced HLECs, providing a potential insight of the m⁶A modification for DC.

Challenges and opportunities for drug delivery to the posterior of the eye

Drug delivery to the posterior segment of the eye remains challenging even though the eye is readily accessible. Its unique and complex anatomy and physiology contribute to the limited options for drug delivery via non-invasive topical treatment, which is the prevalent ophthalmic treatment. To treat the most common retinal diseases, intravitreal (IVT) injection has been a common and effective therapy. With the advancement of nanotechnologies, novel formulations and drug delivery systems are being developed to treat posterior segment diseases. Here, we discuss the recent advancement in ocular delivery systems, including-sustained release formulations, IVT implants, and preclinical topical formulations, and the challenges faced in their clinical translation.

Recent advances in slow and sustained drug release for retina drug delivery

INTRODUCTION

Striking recent advance has occurred in the field of medical retina, greatly because intraocular drugs have been developed, enhancing their clinical efficacy while avoiding systemic side-effects. However, the burden of repeated intraocular administration makes limits the optimal efficacy of treatments, prompting the development of new drugs with prolonged half-life or of sustained drug delivery systems.

AREAS COVERED

In this review, we describe the various drugs and drug delivery systems that have reached the clinical stage and those that are in clinical development and we discuss the limitations to clinical translation.

EXPERT OPINION

Substantial fundamental work is still required to build guidelines on optimal animal models for ocular pharmacokinetics and safety studies depending on the target disease site and the on the type of therapeutic compounds. The effects of a drug administered as a bolus at high concentration in the vitreous might differ from those resulting from the sustained release of a lower concentration, and no delivery platform can be simply adapted to any drug. For the treatment of retinal diseases, development of therapeutic compounds should integrate from its early conception, the combination of an active drug with a specific drug delivery system, administered by a specific route.

The efficacy and safety outcomes of the 0.19 mg fluocinolone acetonide implant after prior treatment with the 0.7 mg dexamethasone implant in patients with diabetic macular edema

Purpose

There are little or no published data comparing the outcomes of ILUVIEN^® (0.19 mg fluocinolone acetonide [FAc]) and OZURDEX^® (0.7 mg dexamethasone [DEX]) implants in patients with diabetic macular edema (DME), and this case sought to compare their outcomes.

Methods

This case was extracted from a monocentric audit involving a pool of 25 patients (33 eyes) with DME and treated with a single FAc implant between October 2013 and December 2016. This case, a 61-year-old male with a pseudophakic lens, is from a patient that had received 4 intravitreal injections of a DEX implant prior to FAc implant and then was monitored for 3 years until re-treatment with a second FAc implant. Parameters measured included visual acuity (VA), central retinal thickness (CRT), and intraocular pressure (IOP).

Results

After the DEX implants, CRT transiently improved. In March 2014, the decision was taken to administer an FAc implant, and this led to a reduction in CRT below 300 µm (from a baseline of 748 µm), and this was sustained for 30 months. VA remained above 65 Early Treatment Diabetic Retinopathy Study letters to month 36, after which time a second FAc implant (in April 2017) was administered due to recurrence of edema and CRT decreased to below 300 µm and VA improved to 70 letters. Side effects included elevated IOP, which was effectively managed with IOP-lowering drops.

Conclusion

A single injection of FAc implant led to sustained improvements in CRT and VA that lasted for between 30 and 36 months, which is in contrast to the DEX implant where re-treatment was generally required within 6–7 months. After 36 months, re-treatment with the FAc implant again led to improved VA and CRT, and responses that were similar to those achieved with the first FAc implant.