fenretinide and Macular-Degeneration

Age-related macular degeneration (AMD) is a highly prevalent condition in an ever-increasing elderly population. Although insidious in the early stages, advanced AMD (neovascular and atrophic forms) can cause significant visual disability and economic burden on health systems worldwide. The most common form, geographic atrophy, has no effective treatment to date, whereas neovascular AMD can be treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections. Geographic atrophy has a slow disease progression and patients tend to have preserved central vision until the final stages. This tendency, coupled with the use of modern imaging modalities, provides a large window of opportunity to intervene with validated methods to assess treatment efficacy. As geographic atrophy is an increasingly common condition with no effective intervention, many treatments are under investigation, one of which is visual cycle modulators. These medications have been shown to reduce lipofuscin accumulation in pre-clinical studies that have led to several clinical trials, reviewed herein.. To assess the efficacy and safety of visual cycle modulators for the prevention and treatment of geographic atrophy secondary to AMD.. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); MEDLINE Ovid; Embase Ovid; Web of Science Core Collection; Scopus; Association for Research in Vision and Ophthalmology (ARVO) website; ClinicalTrials.gov and the WHO ICTRP to 11 January 2020 with no language restrictions. We also searched using the reference lists of reviews and existing studies and the Cited Reference Search function in Web of Science to identify further relevant studies.. We included randomised controlled trials (RCTs) and quasi-randomised clinical studies (if available) that compared visual cycle modulators to placebo or no treatment (observation) in people diagnosed with AMD (early, intermediate or geographic atrophy).. Two authors independently assessed risk of bias in the included studies and extracted data. Both authors entered data into RevMan 5. We resolved discrepancies through discussion. We graded the certainty of the evidence using the GRADE approach.. There is limited evidence to support the use of visual cycle modulators (emixustat and fenretinide) for the treatment of established geographic atrophy due to AMD. The possible reduction in the incidence of CNV observed with fenretinide, and to a lesser extent, emixustat, requires formal assessment in focused studies.

Topics: Aged; Aged, 80 and over; Choroidal Neovascularization; Clinical Trials, Phase II as Topic; Disease Progression; Fenretinide; Geographic Atrophy; Humans; Incidence; Macular Degeneration; Phenyl Ethers; Placebos; Propanolamines; Randomized Controlled Trials as Topic; Visual Acuity; Watchful Waiting

Stargardt disease, an inherited macular dystrophy caused by mutations in the ABCA4 gene encoding a retinal transporter protein, is the most prevalent form of macular degeneration in children. Patients with Stargardt disease develop severe vision loss within their first or second decades of life, which progresses to irreversible decreased visual acuity in almost all cases. Presently, there are no standard treatments for Stargardt disease. However, encouraging progress has been made in the development of innovative approaches to preventing vision loss in Stargardt patients.. Among the promising treatment candidates include ALK-001, fenretinide, and A1120 as pharmacological agents to modulate the visual cycle, StarGen

Topics: Antineoplastic Agents; Fenretinide; Genetic Therapy; Humans; Ligands; Macular Degeneration; Piperidines; Retinal Pigment Epithelium; Stargardt Disease; Stem Cell Transplantation

Excessive accumulation of lipofuscin is associated with pathogenesis of atrophic age-related macular degeneration (AMD) and Stargardt disease. Pharmacologic inhibition of the retinol-induced interaction of retinol-binding protein 4 (RBP4) with transthyretin (TTR) in the serum may decrease the uptake of serum retinol to the retina and reduce formation of lipofuscin bisretinoids. We evaluated in vitro and in vivo properties of the new nonretinoid RBP4 antagonist, A1120.. RBP4 binding potency, ability to antagonize RBP4-TTR interaction, and compound specificity were analyzed for A1120 and for the prototypic RBP4 antagonist fenretinide. A1120 ability to inhibit RPE65-mediated isomerohydrolase activity was assessed in the RPE microsomes. The in vivo effect of A1120 administration on serum RBP4, visual cycle retinoids, lipofuscin bisretinoids, and retinal visual function was evaluated using a combination of biochemical and electrophysiologic techniques.. In comparison to fenretinide, A1120 did not act as a RARα agonist, while exhibiting superior in vitro potency in RBP4 binding and RBP4-TTR interaction assays. A1120 did not inhibit isomerohydrolase activity in the RPE microsomes. A1120 dosing in mice induced 75% reduction in serum RBP4, which correlated with reduction in visual cycle retinoids and ocular levels of lipofuscin fluorophores. A1120 dosing did not induce changes in kinetics of dark adaptation.. A1120 significantly reduces accumulation of lipofuscin bisretinoids in the Abca4(-/-) animal model. This activity correlates with reduction in serum RBP4 and visual cycle retinoids confirming the mechanism of action for A1120. In contrast to fenretinide, A1120 does not act as a RARα agonist indicating a more favorable safety profile for this nonretinoid compound.

Topics: Animals; Antineoplastic Agents; ATP-Binding Cassette Transporters; Cattle; Disease Models, Animal; Fenretinide; Humans; Hydrolases; Ligands; Lipofuscin; Macular Degeneration; Mice; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Mutant Strains; Piperidines; Prealbumin; Retinoids; Retinol-Binding Proteins, Plasma