UNA, when used in the synthesis of a short-interfering RNA (UsiRNA), provides drug-like properties to a siRNA in a novel and proprietary manner; these include protection from enzymatic destruction; reduction, or elimination, of a cytokine response; and preservation of high efficacy. The use of UsiRNA as RNAi-based therapeutics has the potential for both effective protein down regulation with lower total doses of siRNA and an improved safety profile.

"In pre-clinical studies we have completed over the past 12 months, our proprietary UsiRNA constructs have been shown to increase stability, reduce off-target activity and cytokine induction, and improve gene silencing. These characteristics are key to human therapeutic use of UsiRNA and, when formulated with our DilA2 delivery technology, provide a powerful approach to down regulating protein expression via RNAi," stated J. Michael French, President and CEO of MDRNA. "We believe that amending the IP assignment agreement at this time provides us greater flexibility to complete broad target and therapeutic based collaborations with major pharmaceutical companies."

In October 2008, MDRNA completed the acquisition of the patent portfolio related to UNA from RiboTask via an intellectual property assignment agreement, which included certain financial obligations payable by MDRNA to RiboTask in the event of a license, development or sale of UNA-based siRNA for human therapeutic use. Under the renegotiated terms, all future financial obligations payable by MDRNA to RiboTask were eliminated. RiboTask retains rights to manufacture, sell and sublicense UNA technology for use in reagents and diagnostics only.

Mr. French added, "MDRNA and RiboTask have enjoyed a strong and mutually rewarding partnership. I would like to recognize and thank Dr. Jesper Wengel, Suzy Lena and their colleagues at RiboTask, as well as our own scientists, for the tremendous work they have done to rapidly advance this promising technology. We look forward to a continued partnership with Dr. Wengel and his team."

About Unlocked Nucleobase Analog

Unlocked Nucleobase Analog (UNA) is an acyclic ribonucleoside analog having an open sugar ring structure. This change in sugar structure renders this nucleoside analog very flexible. This characteristic is in sharp contrast to the widely used Locked Nucleobase Analog (LNA) that locks the sugar conformation by a bridged bond between C2' and C4' atoms. The flexible nature of UNA reduces the binding affinity between two strands of siRNA molecule and gives unique characteristics to its gene-silencing abilities. MDRNA has demonstrated that UNA has the potential to improve siRNA therapeutics by increasing stability, reducing sense- and antisense-mediated off-target effects and substantially reduces cytokine induction while retaining potency.

About UsiRNAs

UsiRNAs are UNA modified duplex siRNAs in which the bond between two adjacent carbon atoms of ribose is removed. UsiRNAs are fully recognized by the RNAi machinery and provide for potent RNAi activity. Placement of UNA within UsiRNA minimizes the potential for off-target effects by the guide strand as well as undesired activity of the passenger strand. Further, the change in sugar structure renders this unlocked nucleobase analog conformationally flexible. The flexibility of the monomer escapes the body's surveillance mechanisms associated with cytokine induction, as well as providing protection from nuclease degradation.

About the DiLA2 Delivery Platform

The DiLA2 Platform is MDRNA's proprietary platform for creating novel liposomal delivery systems from amino acids. The platform enables MDRNA to tailor the charge, linker and acyl chains of amino acids in order to optimize the liposome for delivery to the target tissue of interest. In addition, the platform is designed to permit attachment of various peptides and other targeting molecules to improve a variety of delivery characteristics. In addition, MDRNA is utilizing peptides for nanoparticle formulations to increase cellular uptake and endosomal release.

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 key therapeutic areas including oncology, metabolic disorders and inflammation. 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 http://www.mdrnainc.com.

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 or a subsidiary to obtain additional funding; (ii) the ability of MDRNA or a subsidiary to attract and/or maintain manufacturing, research, development and commercialization partners; (iii) the ability of MDRNA, a subsidiary and/or a partner to successfully complete product research and development, including preclinical and clinical studies and commercialization; (iv) the ability of MDRNA, a subsidiary and/or a partner to obtain required governmental approvals; and (v) the ability of MDRNA, a subsidiary 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.

SOURCE: MDRNA, Inc.