BOULDER, Colo. and SAN FRANCISCO, May 4 /PRNewswire-FirstCall/ -- Sirna Therapeutics announced today that one of its clinical investigators, Edward Quinlan, M.D., of the Wilmer Eye Institute, The Johns Hopkins University, presented interim data from the ongoing Phase 1 trial for Sirna-027, an siRNA therapeutic for treatment of Age-Related Macular Degeneration (AMD), yesterday. The interim data were presented during the Association for Research in Vision and Ophthalmology (ARVO) 2005 Global Networking Conference and Annual Meeting held from May 1-5 in Ft. Lauderdale, Fla.
Dr. Quinlan reported in his presentation, entitled "siRNA Directed Against VEGFR1 mRNA for AMD," that Sirna-027 appears to be safe and well tolerated at doses tested to date, with no systemic or local adverse events related to the drug. No dose-limiting toxicity has been observed; thus the maximum tolerated dose has not been established. The data demonstrated that visual acuity stabilized in all patients tested.
The open-label, dose-escalation study is ongoing in four prestigious clinical centers: the Wilmer Eye Institute, The Johns Hopkins University; The Cole Eye Institute at The Cleveland Clinic; the Joint Clinical Research Center, Harvard University, Massachusetts Eye and Ear Infirmary; and the Jules Stein Eye Institute, University of California Los Angeles. The purposes of the trial are to establish the safety and tolerability of Sirna-027, its clinical effect on visual acuity, and its potential for biological effect by monitoring changes in optical coherence tomography (OCT) and fluorescein angiography (FA). To date, fourteen patients have each received a single intravitreal dose of Sirna-027 ranging from 100 to 800 micrograms. So far, all patients have experienced visual acuity stabilization during their trial participation -- the longest assessment being 84 days.
Peter K. Kaiser, M.D., of The Cole Eye Institute at The Cleveland Clinic, another Sirna-027 clinical investigator stated, "As an investigator in the Sirna-027 AMD trial and a physician treating patients with AMD, I am very encouraged by the interim data presented at ARVO. The safety profile of the drug is very solid and there seems to be a promising trend in visual acuity improvement observed that warrants further study of Sirna-027 in a Phase 2 multi-dose trial. The data so far seems to suggest that siRNAs may emerge as an important and novel therapeutic modality for AMD."
Roberto Guerciolini, M.D., Sirna's Chief Medical Officer, commented, "We are optimistic for the outcome of the Phase 1 trial as evidenced by the interim evaluation presented by Dr. Quinlan. Considering that the findings presented are derived from a single low-dose administration, we believe that longer duration of dosing will result in therapeutic benefit to patients with AMD. Thus, we are committed to completing the dose escalation in the current Phase I trial and, based on final data, would anticipate moving forward with a multi-dose, placebo-controlled, Phase 2 investigation."
Sirna-027 is the first chemically optimized short interfering RNA (siRNA) to be tested in a human clinical trial. The compound targets Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1), a key component of the clinically validated vascular endothelial growth factor (VEGF) pathway. VEGFR-1 is found primarily on vascular endothelial cells and is stimulated by both VEGF and placental growth factor (PlGF) resulting in the growth of new blood vessels. By targeting VEGFR-1, Sirna-027 is designed to reduce pathologic angiogenesis mediated by both VEGF and PlGF.
Howard Robin, Sirna's President and Chief Executive Officer, commented, "This is a significant event in the development of siRNAs as therapeutics. We are pleased that Dr. Quinlan had the opportunity to present Phase I interim data as part of an important forum regarding treatment options for AMD. We look forward to completing this trial, analyzing the final data set and preparing for Phase 2."
Age-related macular degeneration is the leading cause of visual impairment affecting more than 1.5 million adults over the age of 50 in the United States. Age-related macular degeneration (AMD) is an eye disease that destroys central vision by damaging the macula. The macula is part of the retina, a thin layer of nerve cells that lines most of the inside of the eye. Nerve cells in the retina detect light and send signals to the brain about what the eye sees. The macula, near the center of the retina at the back of the eye, provides the clear, sharp, central vision that is used to focus on objects that are in front of the eye. The rest of the retina provides side (peripheral) vision. Because AMD does not affect side vision, it does not lead to total blindness.
AMD affects about 9% of people in the U.S. over the age of 40. After 50, it occurs with increasing frequency as people age. About 25% of people between 65 and 74 are affected and about 28% of people 75 and older. There are two types of AMD. Either type may affect one or both eyes. Dry age- related macular degeneration, the most common form, does not usually cause severe vision loss. Wet age-related macular degeneration is much less common but can damage the macula quickly causing permanent damage. Wet AMD, also called exudative AMD, often develops in areas where dry AMD exists. Vision loss from both wet and dry AMD is caused by damage to the nerve cells in the macula and the cause of each condition is unknown.
About RNA interference
RNA interference (RNAi) is a natural, selective process for turning off genes. RNAi is triggered by short interfering RNA (siRNA) molecules that engage a group of cellular proteins, known as RISC (RNA induced silencing complex). The RISC guides the siRNA to its target messenger RNA (mRNA, the messenger between DNA and proteins) by complementary base pairing for the targeted break-up of the mRNA thus halting protein expression or viral replication. The RISC-siRNA-complex binds and cleaves multiple mRNA molecules in a catalytic fashion.
About Sirna Therapeutics
Sirna Therapeutics is a clinical-stage biotechnology company developing RNAi-based therapies for serious diseases and conditions, including age- related macular degeneration (AMD), Huntington's disease, diabetes, asthma, oncology, hepatitis C and hair removal. Sirna Therapeutics has initiated a Phase 1 clinical trial for its most advanced compound, Sirna-027, a chemically modified siRNA targeting the clinically validated vascular endothelial growth factor pathway to treat AMD. Sirna Therapeutics has strategic partnerships with Eli Lilly and Company, Targeted Genetics and Archemix Corporation and a leading intellectual property portfolio in RNAi. More information on Sirna Therapeutics is available on the Company's web site at http://www.sirna.com/.
Statements in this press release which are not strictly historical are "forward-looking" statements which should be considered as subject to many risks and uncertainties. For example, Sirna's ability to develop a product for the treatment of age-related macular degeneration and operate as a going concern is contingent upon having readily available cash to fund its operating programs and is subject to the escalating expenses and risks associated with the initiation of additional clinical trials and their potential outcomes. Additional risks and uncertainties include Sirna's early stage of development and short operating history, Sirna's history and expectation of losses and need to raise capital, Sirna's need to obtain clinical validation and regulatory approval for products, Sirna's need to obtain and protect intellectual property, risk of third-party patent infringement claims, Sirna's need to attract and retain qualified personnel, Sirna's need to engage collaborators, availability of materials for product manufacturing, the highly competitive nature of the pharmaceutical market, the limited trading volume and history of volatility of Sirna's common stock, Sirna's concentration of stock ownership, and risks from relocating Sirna headquarters. These and additional risk factors are identified in Sirna's Securities and Exchange Commission filings, including the Forms 10-K and 10-Q and in other SEC filings. Sirna undertakes no obligation to revise or update any forward- looking statements in order to reflect events or circumstances that may arise after the date of this release.
Rebecca Galler Robison, Senior Director, Corporate Strategy of Sirna
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