First Demonstration of Systemic siRNA Efficacy at Therapeutically Relevant Doses is Published by Sirna Therapeutics
Breakthrough research published in Nature Biotechnology describes significant anti-viral activity of chemically optimized siRNA
SAN FRANCISCO and BOULDER, Colo., July 25 /PRNewswire-FirstCall/ -- Sirna Therapeutics, Inc. (Nasdaq: RNAI) announced today the publication in Nature Biotechnology of a breakthrough study demonstrating a 95% knockdown of hepatitis B virus (HBV). In the study, Sirna used its chemically optimized short interfering RNA (siRNA) at 1, 3 and 5 mg/kg together with encapsulation and delivery technology provided by Protiva Biotherapeutics Inc. This is the first demonstration of systemic siRNA efficacy at therapeutically relevant doses and establishes a strong scientific foundation for broad human application of RNAi-based therapeutics.
The study demonstrated that Sirna's chemically optimized and encapsulated siRNAs have high potency and prolonged duration of activity in vivo. The siRNA formulation, targeting HBV, was administered by standard intravenous injection to mice carrying replicating HBV. Three therapeutically relevant doses of 1, 3, or 5 mg/kg resulted in up to a 95% dose dependent reduction in serum HBV DNA levels. A similar reduction was observed in Hepatitis B Surface Antigen protein levels. The anti-viral activity persisted for at least seven days.
This unprecedented efficacy correlates with a significantly longer circulation time of siRNAs in blood plasma and residence time in the liver compared to unmodified and non-encapsulated siRNAs. Importantly, Sirna modified and optimized the siRNAs used in the study to abrogate the induction of serum interferon-alpha (IFN-alpha) and inflammatory cytokines (IL-6, TNF-alpha) thereby further demonstrating Sirna's capability to chemically modify RNAi-based therapeutics to modulate cellular responses.
"We are extremely pleased by the significant knockdown of HBV with low doses of our encapsulated siRNA," stated Sirna Senior Vice President and Chief Scientific Officer, Barry Polisky, PhD. "With these results, we have established a new benchmark for siRNA efficacy in vivo. This is the second study published by Sirna scientists that validates the efficacy of chemically optimized siRNAs in vivo. These robust results further underscore Sirna's leadership position and extensive experience in RNA biology and chemistry. Sirna is building on these landmark results as we focus our human clinical program on hepatitis C. We continue to improve the efficacy of our anti-viral compounds through proprietary modification and delivery approaches and plan to initiate hepatitis C clinical trials next year."
Ian MacLachlan, PhD, Chief Scientific Officer of Protiva Biotherapeutics Inc., said, "The high degree of efficacy observed in this study is superior to all other previously reported data for any systemically delivered siRNA and is a direct result of combining Sirna's expertise in chemical modifications with Protiva's encapsulation and delivery technology."
Sirna initiated primate studies in its hepatitis C program in June 2005 and expects to commence Phase I human clinical trials in 2006.
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 Nature Biotechnology
Nature Biotechnology is a premier monthly journal covering the science and business of biotechnology. It publishes new concepts in technology/methodology of relevance to the biological, biomedical, agricultural and environmental sciences as well as covers the commercial, political, ethical, legal, and societal aspects of this research. The first function is fulfilled by the peer-reviewed research section, the second by the expository efforts in the front of the journal. Nature Biotechnology provides researchers with news about business and provides the business community with news about research developments. According to the ISI Journal Citation Reports, Nature Biotechnology continues to rank first among primary research journals in the category of 'biotechnology and applied microbiology.'
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), hepatitis B and C, dermatology, asthma, Huntington's Disease, diabetes and oncology. Sirna Therapeutics has presented interim Phase 1 clinical trial data for its most advanced compound, Sirna-027, a chemically optimized 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, Archemix Corporation and Protiva Biotherapeutics. Sirna has a leading intellectual property portfolio in RNAi with 43 issued patents and over 250 pending applications worldwide. More information on Sirna Therapeutics is available on the Company's web site at http://www.sirna.com/.[br]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, most drug candidates do not become approved drugs. 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.
About Protiva Biotherapeutics
Protiva is a clinical-stage biotechnology company developing therapeutic products to fight serious human disease. Protiva is a private company whose current investors include MDS Capital Corp., GrowthWorks and the Business Development Bank of Canada. Protiva's first product candidate, Pro-1, is in a Phase I clinical trial in an oncology application. Protiva has active siRNA-based product development programs in oncology, infectious and metabolic disease. Protiva's headquarters is in Seattle, WA.
CONTACT: Rebecca Galler Robison, Senior Director, Corporate Strategy of Sirna Therapeutics, Inc., +1-303-449-6500 or Zack Kubow of The Ruth Group, +1-646-536-7020, for Sirna Therapeutics, Inc.; or Mark Murray, Chief Executive Officer of Protiva Biotherapeutics Inc., +1-206-325-2412
[br]Web site: http://www.sirna.com
SOURCE Sirna Therapeutic
楼主: liver411
发表于 2005-8-8 08:59
应该是目前RNAi研究的领先者. 下面这个是新西兰号角报道的新闻的原厂商新闻公布: 
