To investigate the safety and preliminary efficacy of OT-551, a disubstituted hydroxylamine with antioxidant properties, for the treatment of geographic atrophy (GA), the advanced atrophic form of age-related macular degeneration (AMD).
The study was a single-center, open-label phase II trial, enrolling 10 participants with bilateral GA. Topical 0.45% OT-551 was administered in one randomly assigned eye three times daily for 2 years. Safety measures were assessed by complete ophthalmic examination, fundus photography, and review of symptoms. The primary efficacy outcome measure was the change in best corrected visual acuity at 24 months. Secondary efficacy measures included changes in area of GA, contrast sensitivity, microperimetry measurements, and total drusen area from baseline.
Study drug was well tolerated and was associated with few adverse events. The mean change in BCVA at 2 years was +0.2 ± 13.3 letters in the study eyes and -11.3 ± 7.6 letters in fellow eyes (P = 0.0259). However, no statistically significant differences were found between the study and fellow eyes for all other secondary outcome measures.
OT-551 was well tolerated by study participants and was not associated with any serious adverse effects. Efficacy measurements in this small study indicate a possible effect in maintaining visual acuity. However, the absence of significant effects on other outcomes measures in this study suggests that OT-551, in the current concentration and mode of delivery, may have limited or no benefit as a treatment for GA (ClinicalTrials.gov number, NCT00306488).
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"OT-551, a synthetic lipophilic, disubstituted hydroxylamine , was developed as an antioxidant, formulated as an eye drop and used in a phase II study (NTC00306488) designed to test whether OT-551 could slow the progression of GA in eyes with AMD. The drug showed no benefit as a treatment for GA . SeeTable 1. "
[Show abstract][Hide abstract]ABSTRACT: Currently, there is no treatment to stop the progression of geographic atrophy, the advanced form of non-exudative (dry) age-related macular degeneration. Several promising therapies are being investigated in clinical trials such as antioxidants, neuroprotection agents, complement inhibitors, vascular enhancers, visual cycle modulators, and stem cell therapies. This review discusses the possible treatments that may potentially be available in the future to prevent disease progression.
"Age-related macular degeneration (AMD) is a global epidemic with an estimated worldwide prevalence of 30 to 50 million
, and a leading cause of blindness in people aged over 65 (reviewed in
). While anti-vascular endothelial growth factor (VEGF) therapy has proved to be of benefit for neovascular or ‘wet’ AMD
, there are presently no treatments that mitigate progression of photoreceptor loss in the more common atrophic or ‘dry’ form of AMD
. Although the pathogenesis of AMD is a complex multifactorial process, the recent discovery of a direct association of complement activation with the incidence of AMD has firmly established inflammation as an important factor mediating its pathogenesis
[Show abstract][Hide abstract]ABSTRACT: Aim
Complement activation is associated with the pathogenesis of age-related macular degeneration (AMD). We aimed to investigate whether 670-nm light treatment reduces the propagation of complement in a light-induced model of atrophic AMD.
Sprague–Dawley (SD) rats were pretreated with 9 J/cm2 670-nm light for 3 minutes daily over 5 days; other animals were sham treated. Animals were exposed to white light (1,000 lux) for 24 h, after which animals were kept in dim light (5 lux) for 7 days. Expression of complement genes was assessed by quantitative polymerase chain reaction (qPCR), and immunohistochemistry. Counts were made of C3-expressing monocytes/microglia using in situ hybridization. Photoreceptor death was also assessed using outer nuclear layer (ONL) thickness measurements, and oxidative stress using immunohistochemistry for 4-hydroxynonenal (4-HNE).
Following light damage, retinas pretreated with 670-nm light had reduced immunoreactivity for the oxidative damage maker 4-HNE in the ONL and outer segments, compared to controls. In conjunction, there was significant reduction in retinal expression of complement genes C1s, C2, C3, C4b, C3aR1, and C5r1 following 670 nm treatment. In situ hybridization, coupled with immunoreactivity for the marker ionized calcium binding adaptor molecule 1 (IBA1), revealed that C3 is expressed by infiltrating microglia/monocytes in subretinal space following light damage, which were significantly reduced in number after 670 nm treatment. Additionally, immunohistochemistry for C3 revealed a decrease in C3 deposition in the ONL following 670 nm treatment.
Our data indicate that 670-nm light pretreatment reduces lipid peroxidation and complement propagation in the degenerating retina. These findings have relevance to the cellular events of complement activation underling the pathogenesis of AMD, and highlight the potential of 670-nm light as a non-invasive anti-inflammatory therapy.
Full-text · Article · Nov 2012 · Journal of Neuroinflammation
"Only dietary supplements are available to treat dry type AMD. Clinical trials with Othera Pharmaceuticals’ antioxidant eye drops OT551 for dry type showed promise in phase 1 trials, but failed to demonstrate any benefit greater than from placebo in phase 2 trials . Recently, the Federal Drug Administration approved “Center Sight”—a tiny implantable miniature telescope (IMT). "
[Show abstract][Hide abstract]ABSTRACT: We describe the synthesis and use of an efficient nano carrier molecule for retinal delivery of a nano chitosan peptide that has potential application for treating age-related macular degeneration (AMD). We chose serine-threonine-tyrosine as the peptide sequence because it is well known to act as a transduction signaling agent within and between retinal pigmented epithelium cells.
A nanoformulation of a water-soluble chitosan conjugated with a peptide (serine-threonine-tyrosine) was synthesized by a method developed in our laboratory and characterized with dynamic light scattering, zeta potential, transmission electron microscopy, nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The in vitro efficacy of the formulation was evaluated in retinal cells with confocal microscopy by studying the formulation's action on tyrosine kinase activity.
The conjugated nano chitosan peptide showed evidence of tyrosine kinase activity as seen by fluorescent signals under confocal microscopy, while nano chitosan or peptide alone did not show such activity.
Conjugated nano chitosan peptide may promote binding and engulfment. This molecule is an excellent carrier for retinal drug delivery and has the potential to treat age-related macular degeneration.