Current and Emerging Treatment for Diabetic Macular Edema

Rho-Kinase Inhibitors for the Treatment of Refractory Diabetic Macular Oedema

Diabetic macular oedema (DMO) is one of the leading causes of vision loss associated with diabetic retinopathy (DR). New insights in managing this condition have changed the paradigm in its treatment, with intravitreal injections of antivascular endothelial growth factor (anti-VEGF) having become the standard therapy for DMO worldwide. However, there is no single standard therapy for all patients DMO refractory to anti-VEGF treatment; thus, further investigation is still needed. The key obstacles in developing suitable therapeutics for refractory DMO lie in its complex pathophysiology; therefore, there is an opportunity for further improvements in the progress and applications of new drugs. Previous studies have indicated that Rho-associated kinase (Rho-kinase/ROCK) is an essential molecule in the pathogenesis of DMO. This is why the Rho/ROCK signalling pathway has been proposed as a possible target for new treatments. The present review focuses on the recent progress on the possible role of ROCK and its therapeutic potential in DMO. A systematic literature search was performed, covering the years 1991 to 2021, using the following keywords: "rho-Associated Kinas-es", "Diabetic Retinopathy", "Macular Edema", "Ripasudil", "Fasudil" and "Netarsudil". Better insight into the pathological role of Rho-kinase/ROCK may lead to the development of new strategies for refractory DMO treatment and prevention.

Reduction in Retinal Thickness Fluctuations After Treatment With Fluocinolone Acetonide Implant for DME: A Post-Hoc Analysis of the USER Study

BACKGROUND AND OBJECTIVE

Assess fluocinolone acetonide implant (FAc) effects on diabetic macular edema (DME) retinal thickness fluctuations.

PATIENTS AND METHODS

A post-hoc chart review of the real-world USER study analyzed patients receiving 0.2 μg/day FAc implant. The percentage of eyes with central subfield thickness (CST) of 300 µm or less were compared pre- and post-FAc implant; mean retinal thickness amplitude (RTA), retinal thickness standard deviation (RTSD), and two case studies were analyzed.

RESULTS

One hundred thirty patients (mean age: 69.6 years) presented; CST was available for 120 of 160 treated eyes. Mean RTA decreased significantly post-FAc implant (P < .001) regardless of baseline visual acuity (VA). Correlations with last-observed VA (R²) were: RTA, 0.1197; retinal thickness standard deviation (RTSD), 0.1526; and area under the CST-time curve (AUC CST), 0.0981. After FAc implant, the percentage of eyes with CST of 300 μm or less was significantly greater versus baseline (P < .05).

CONCLUSIONS

Retinal thickness fluctuations significantly declined after FAc and correlated with improvement in VA. Both RTSD and RTA measures correlated more closely to last observed VA than AUC CST itself. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:298-306.].

Clinical impact of the 0.2 µg/day fluocinolone acetonide intravitreal implant: outcomes from the ILUVIEN® clinical evidence study in Portugal

Introduction:

The ILUVIEN^® (fluocinolone acetonide) Clinical Evidence in Portugal (ICE-PT) study is a retrospective, multicenter, observational study evaluating the effectiveness and safety of the FAc implant in patients with diabetic macular edema.

Methods:

Patients included in this study had received the 0.2 µg/day fluocinolone acetonide implant for the treatment of diabetic macular edema and had measurements of visual acuity and retinal thickness assessed by optical coherence tomography for at least 12 months pre- and post-fluocinolone acetonide implant administration, with ⩾2 follow-up visits. Outcomes measured included visual acuity, central foveal thickness, and intraocular pressure.

Results:

There was a significant increase in mean visual acuity compared with baseline at 3, 6, 9, and 12 months post-fluocinolone acetonide in both the overall study population and the pseudophakic subgroup (p < 0.05 at all time points in both groups). A significant reduction in mean central foveal thickness compared with baseline was seen in the overall study population at 3, 6, 9, and 12 months post-fluocinolone acetonide (p < 0.05 at all time points). At 12-month post-fluocinolone acetonide, a small but significant intraocular pressure increase of 1.0 mmHg was seen in the overall study population.

Conclusion:

The results of this analysis show that switching from the current standard of care to the fluocinolone acetonide implant leads to beneficial effects in terms of vision and retinal structure in patients with diabetic macular edema and that patients benefited from FAc implant administration, regardless of lens status.

Diabetic Macular Edema: Current Understanding, Pharmacologic Treatment Options, and Developing Therapies

Diabetic retinopathy and diabetic macular edema comprise a major source of visual disability throughout the developed world. The etiology and pathogenesis of macular edema is intricate and multifactorial, in which the hyperglycemic state in diabetes induces a microangiopathy. Through several inflammatory and vasogenic mediators, including vascular endothelial growth factor (VEGF) upregulation and inflammatory cytokines and chemokines, pathologic changes are induced in the vascular endothelium triggering breakdown of the blood retinal barrier, causing extravasation of fluid into the extracellular space and manifesting clinically as macular edema, resulting in visual loss. The advent of medications targeting the VEGF pathway has led to great clinical improvements compared with the previous standard of care of laser therapy alone, as shown in studies such as RISE, RIDE, VIVID, VISTA, and DRCR. However, analyses have shown that many patients have inadequate response or are nonresponders to anti-VEGF therapy, demonstrating the need for additional therapies to more comprehensively treat this disease. Although corticosteroid treatments and implants have demonstrated some efficacy in adjunctive and supplemental treatment, the need to more adequately treat macular edema remains. Our knowledge of diabetic macular edema continues to grow, leading to new currently available and emerging pharmacotherapies to further enhance our treatment and restore vision in those affected by diabetic macular edema. This review will discuss the pathogenesis of diabetic macular edema and the pharmacologic therapies available for its treatment, including anti-VEGF, steroids, and newer therapies still in development, such as angiopoietin antagonists, Tie2 agonists, kallikrein inhibitors, interleukin inhibitors, and others.