MDRNA, Inc. Reports Its Proprietary RNAi-Based Compounds Are Well Tolerated and Demonstrate High Potency Against Multiple Targets in Preclinical Studies

BOTHELL, WA--(Marketwire - May 19, 2009) -

MDRNA, Inc. (NASDAQ: MRNA) announced today positive in vivo efficacy data showing that its proprietary UsiRNA constructs are highly potent and highly specific against ApoB and Factor VII message. The data are being presented today by Michael V. Templin, Ph.D., Vice President, Discovery Research and Pharmaceutical Development of MDRNA, at the TIDES Oligonucleotide and Peptide® Technology and Product Development Conference in Las Vegas, Nevada.

“Data from recent in vivo studies using our UsiRNAs targeting ApoB message confirm that RNA interference is the mechanism of action by which knockdown occurs, giving us high confidence that our UsiRNAs work by a sequence-specific mechanism,” stated Barry Polisky, Ph.D., Chief Scientific Officer of MDRNA. “Data from the Factor VII studies indicate that a siRNA in our lead formulation achieved greater than 90% knockdown at 1 mg/kg with duration of effect of up to 28 days. This level of inhibition and duration of effect meets or exceeds published data for Factor VII.”

Dr. Polisky added, “Data from rodent studies with our DiLA2 delivery system also continue to show encouraging results, with potency, specificity and duration of effect data now achieved for four independent liver targets, including ApoB, PCSK9, DGAT2 and Factor VII. The absence of histological changes in the liver with doses up to 9 mg/kg in rodents confirms that our DiLA2 liposomes are well tolerated.”

About UsiRNAs

UsiRNAs are duplex siRNAs that are modified with non-nucleotide acyclic monomers, termed unlocked nucleobase analogs (UNA), 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

DiLA2 is MDRNA’s proprietary platform technology 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 by combining novel RNAi-based compounds and proprietary peptide- and liposomal-based drug delivery technologies to provide superior therapeutic options. Our multi-disciplinary portfolio of capabilities includes molecular biology, cellular biology, formulation expertise, peptide and alkylated amino acid chemistry, pharmacology, toxicology and bioinformatics. We are applying this expertise to a single, integrated drug discovery platform that will be the engine for our clinical pipeline and a versatile platform for establishing broad therapeutic partnerships. We are also building on new technologies, such as UsiRNAs that incorporate the non-nucleotide moiety Unlocked Nucleobase Analog (UNA) within the siRNA molecule, that we expect to lead to safer and more effective RNAi-based therapeutics. By combining broad expertise in siRNA science with proven delivery platforms and a strong and growing IP position, MDRNA is well positioned as a leading RNAi therapeutics company and value-added collaborator for our research partners. Additional information about MDRNA, Inc. is available at http://www.mdrnainc.com.

MDRNA Forward-Looking Statement

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.