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May 28, 2006
All dose groups of siRNA show positive change in visual acuity
Ophthalmology Times May 1, 2006
Baltimore—Intravitreal injection of a small interfering RNA molecule (Sirna-027, Sirna Therapeutics Inc.) appears to be safe and well tolerated by patients for treatment of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD), according to Edward J. Quinlan, MD, who reported the preliminary data from the phase I clinical trial. "This trial involves a novel pharmacologic agent known as a small interfering RNA (siRNA) molecule," said Dr. Quinlan, assistant professor of ophthalmology, Johns Hopkins University School of Medicine, Wilmer Eye Institute, Baltimore. "RNA interference is a recently discovered process for silencing gene expression."It has been shown that when double-stranded RNA enters a cell, an enzyme known as DICER cleaves it into smaller fragments that can combine with proteins to form a complex called RISC, or the RNA-induced silencing complex,"RISC, in turn, uses small RNA fragments to look for complementary sequences on messenger RNA to bind to and degrade."This silences the expression of the gene. The short RNA fragments have become known as siRNAs," said Dr. Quinlan, The siRNAs are highly versatile and can be designed to target any gene. In this case, Sirna-027 is designed to target vascular endothelial growth factor receptor 1 (VEGFR1) mRNA. Dr. Quinlan explained that Sirna-027 has been "chemically optimized" to enhance its stability, which is in contrast to most siRNAs, which have a short half life.
Posted by mehdi khanlari at May 28, 2006 10:22 PM