January 19, 2010 08:00 ET

MDRNA Demonstrates Significantly Reduced Off-Target Activity for Proprietary RNAi-Based Compounds

Results Show Greater Target Specificity for Novel UsiRNA Constructs Based on Proprietary Unlocked Nucleobase Analog Technology

BOTHELL, WA--(Marketwire - January 19, 2010) - MDRNA, Inc. (NASDAQ: MRNA), a leading RNAi-based drug discovery and development company, today announced the presentation of data highlighting the ability of the UsiRNA construct to significantly minimize off-target effects while maintaining potent RNA Interference (RNAi) activity. Narendra Vaish, Ph.D., MBA, Associate Director, Discovery Research and Pharmaceutical Development, presented the data at the Keystone Symposia on "RNA Silencing: Mechanism, Biology and Application" from January 14 to 19, 2010, Keystone Resort, Keystone, Colorado.

UsiRNAs are MDRNA's proprietary constructs in which Unlocked Nucleobase Analogs (UNA) strategically replace ribonucleobases. Placement of UNA in the passenger strand specifically blocks the activity of this strand to function in RNAi, thus decreasing off-target activity. Placement of UNA within the guide strand confers greater specificity upon RNAi by inhibiting micro-RNA-like effects. Using microarray analysis to simultaneously measure the expression levels of more than 30,000 genes, a UNA in the passenger strand reduced the off-target effects by greater than two-fold as compared to a standard siRNA. More importantly, a UsiRNA, with both passenger and guide strand UNA placements reduced the off-targets effects by more than 10-fold compared to a standard siRNA.

MDRNA also reported delivery of UsiRNA against Survivin and PLK-1, by MDRNA's proprietary DiLA2-based liposome formulations via systemic (liver cancer) or local (bladder cancer) administration, and demonstrated potent and persistent target knock-down and inhibition of tumor growth. Significant knockdown in the expression level of a liver gene has also been described in non-human primates following intravenous (systemic) administration of a UsiRNA using DiLA2 liposomes.

"These new data highlight the ability of our UsiRNA construct to inhibit passenger strand activity and achieve greater guide strand specificity," said Dr. Barry Polisky, Chief Scientific Officer of MDRNA. "These advantages are reflected in the microarray data which indicate UsiRNAs mitigate off-target effects that can occur in RNAi. The inhibition of non-cancer, and cancer targets in two divergent models via different routes of administration, demonstrates the strength of pairing the UsiRNA and DiLA2 delivery platforms for the development of RNAi-based therapeutics."

About MDRNA, Inc.

MDRNA is a biotechnology company focused on the development and commercialization of therapeutic products based on RNA interference (RNAi). Our goal is to improve human health through the development of RNAi-based compounds and drug delivery technologies that together provide superior therapeutic options for patients. Over the past decade, we have developed substantial capabilities in molecular biology, cellular biology, lipid chemistry, peptide chemistry, pharmacology and bioinformatics, which we are applying to a wide range of RNAi technologies and delivery approaches. These capabilities plus the in-licensing of key RNAi-related intellectual property have rapidly enabled us to become a leading RNAi-based therapeutics company with a pre-clinical pipeline in oncology. Through our capabilities, expertise and know-how, we are incorporating multiple RNAi technologies as well as peptide- and lipid-based delivery approaches into a single integrated drug discovery platform that will be the engine for our clinical pipeline as well as a versatile platform for establishing broad therapeutic partnerships with biotechnology and pharmaceutical companies. We are also investing in new technologies that we expect to lead to safer and more effective RNAi-based therapeutics while aggressively building upon our broad and extensive intellectual property estate. By combining broad expertise in siRNA science with proven delivery platforms and a strong IP position, MDRNA is well positioned as a leading RNAi-based drug discovery and development company. Additional information about MDRNA, Inc. is available at

MDRNA Forward-Looking Statements

Statements made in this news release may be forward-looking statements within the meaning of Federal Securities laws that are subject to certain risks and uncertainties and involve factors that may cause actual results to differ materially from those projected or suggested. Factors that could cause actual results to differ materially from those in forward-looking statements include, but are not limited to: (i) the ability of MDRNA to obtain additional funding; (ii) the ability of MDRNA to attract and/or maintain manufacturing, research, development and commercialization partners; (iii) the ability of MDRNA and/or a partner to successfully complete product research and development, including preclinical and clinical studies and commercialization; (iv) the ability of MDRNA and/or a partner to obtain required governmental approvals; and (v) the ability of MDRNA and/or a partner to develop and commercialize products that can compete favorably with those of competitors. Additional factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements are contained in MDRNA's most recent periodic reports on Form 10-K and Form 10-Q that are filed with the Securities and Exchange Commission. MDRNA assumes no obligation to update and supplement forward-looking statements because of subsequent events.

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