Marina Biotech, Inc. Announces Significant Knockdown of Gene Targets in Tumors With a microRNA Mimetic

BOTHELL, WA--(Marketwire - September 13, 2010) -  Marina Biotech, Inc. (NASDAQ: MRNA), a leading RNA-based drug discovery and development company, today reported results from in vivo studies in rodent cancer models focused on effective delivery of a microRNA (miRNA) mimetic using Marina Biotech's proprietary Di-Alkylated Amino Acid (DiLA²) delivery system. Organ and tumor distribution studies demonstrated up to a 100-fold increase in miRNA copies per tumor cell as compared to baseline levels. Similar increases in the miRNA levels were noted in liver, lung, and heart after systemic administration of the mimetic formulated in DiLA²-based liposomes. Moreover, delivery of the miRNA mimetic in DiLA² liposomes demonstrated approximately 60% knockdown of mRNA for two genes whose down-regulation is the intended target of the miRNA mimetic.

"These data highlight the significant breadth in the potential uses of Marina Biotech's DiLA² delivery system for RNA-based therapeutics," said J. Michael French, President and CEO of Marina Biotech at the Rodman & Renshaw 12th Annual Healthcare Conference in New York City. "The results support our plans to expand our therapeutic reach beyond our proprietary UsiRNA-based therapies to include both microRNA mimetics and antagomirs. Our broad delivery capability which includes both the DiLA² and SMARTICLES^® technologies combined with our conformationally-restricted nucleotide (CRN) technology for stabilizing single-stranded oligonucleotides, creates a formidable drug discovery engine for the development of miRNA-based therapeutics."

"These experiments further demonstrate the flexibility of our DiLA²-based delivery technology for systemic administration," stated Barry Polisky, Ph.D., Chief Scientific Officer of Marina Biotech, Inc. "The DiLA² delivery system is capable of efficiently delivering small RNAs into cells and releasing their cargo to affect miRNA-mediated pathways, or siRNA-mediated knockdown, of a gene target. This is very exciting in the context of our ongoing efforts to develop RNA-based molecules that regulate the protein production of specific therapeutic targets involved in a host of diseases, including cancer."

Effective delivery is a well-recognized challenge in the development of RNA-based therapeutics. The versatility of the DiLA² system provides for a rapid and scientifically robust process for improving the delivery characteristics of novel formulations to meet specific requirements of a particular therapeutic application, i.e., systemic administration for delivery to liver hepatocytes or local delivery to cells, such as the lung epithelium.

About Marina Biotech's DiLA² RNA Delivery Platform

DiLA² is Marina Biotech's proprietary delivery platform of novel synthetic di-alkylated amino acid compounds used to make liposomal delivery formulations. The DiLA² platform enables Marina Biotech to tailor the charge, linker and acyl chains of amino acids in order to configure liposomes for delivery to target tissues 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.

About Marina Biotech's CRN Nucleotide Analogs

CRNs (Conformationally Restricted Nucleotides) are novel nucleoside analogs in which the flexible ribose sugar is locked into a rigid conformation by a small chemical linker, providing stability to oligonucleotides, and the opportunity to tailor on a position-by-position basis the specificity of a nucleic-acid based therapeutic or diagnostic.

About Marina Biotech, Inc.

Marina Biotech (formerly known as MDRNA, Inc.) is a biotechnology company focused on the development and commercialization of therapeutic products based on RNA interference (RNAi). The Marina Biotech pipeline currently includes a clinical program in Familial Adenomatous Polyposis (a precancerous syndrome) and two preclinical programs -- in hepatocellular carcinoma and bladder cancer. Marina Biotech's 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. Additional information about Marina Biotech is available at http://www.marinabio.com.

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 Marina Biotech to obtain additional funding; (ii) the ability of Marina Biotech to attract and/or maintain manufacturing, research, development and commercialization partners; (iii) the ability of Marina Biotech and/or a partner to successfully complete product research and development, including preclinical and clinical studies and commercialization; (iv) the ability of Marina Biotech and/or a partner to obtain required governmental approvals; and (v) the ability of Marina Biotech 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 Marina Biotech's most recent periodic reports on Form 10-K (under MDRNA, Inc.) and Form 10-Q that are filed with the Securities and Exchange Commission. Marina Biotech assumes no obligation to update and supplement forward-looking statements because of subsequent events.

Contact Information:

Contacts:
Marina Biotech, Inc.
Pete Garcia
Chief Financial Officer
(425) 908-3603
pgarcia@marinabio.com

Westwicke Partners (Investors):
Stefan Loren, Ph.D.
(443) 213-0507
sloren@westwicke.com

John Woolford
(443) 213-0506
john.woolford@westwicke.com

McKinney|Chicago (Media):
Alan Zachary
(312) 944-6784 × 316 or
(708) 707-6834
azachary@mckinneychicago.com