MDRNA, Inc. Reports Effective Local Delivery of a UsiRNA in an In Vivo Model of Bladder Cancer

BOTHELL, WA--(Marketwire - June 8, 2009) - MDRNA, Inc. (NASDAQ: MRNA) announced today in vivo data from a bladder cancer model demonstrating effective localized delivery of a UsiRNA to a solid tumor, thus further expanding the delivery capabilities of the DiLA2 Platform. In addition, the Company reported in vivo data demonstrating the ability of its proprietary peptide-based nanoparticle technology to significantly improve siRNA delivery efficiency. The integration of the peptide nanoparticle technology with the DiLA2 Platform resulted in 85% knockdown of ApoB messenger RNA while decreasing the overall amount of the DiLA2 delivery vehicle by 45%. The data are being presented today at the RNA Interference Summit in San Francisco by Roger Adami, Ph.D., Associate Director, Molecular Pharmaceutics, MDRNA, Inc.

Dr. Adami will also present data demonstrating knockdown of additional hepatocyte targets in rodent models. The DiLA2 liposomes showed 90% knockdown of DGAT2 in mice following a single 2 mg/kg administration and a 75% knockdown of PCSK9 with a single 2 mg/kg dose. This highly efficient delivery to hepatocytes provides the basis for MDRNA's development pipeline in oncology.

"The data reported today demonstrate the breadth and versatility of the DiLA2 delivery system," stated Barry Polisky, Ph.D., Chief Scientific Officer. "We believe that the DiLA2 Platform will enable effective therapeutic applications of siRNAs in oncology and various other disease indications. Additionally, peptide-siRNA particles combined with the DiLA2 Platform will provide improved delivery efficiency of RNAi-based therapeutics. During 2009, we intend to expand the capabilities of the DiLA2 delivery system to target multiple oncology indications beyond our initial internal program in liver cancer."

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 a 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 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 and 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.

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.

Contact Information: Contacts: Matthew D. Haines Senior Director, Investor Relations and Corporate Communications (212) 209-3874 McKinney|Chicago (Media) Alan Zachary (312) 944-6784 x 316 or (708) 707-6834