Marina Biotech Achieves Significant Improvements in siRNA Delivery via New DiLA2-Based Compositions

BOTHELL, WA--(Marketwire - November 18, 2010) - Marina Biotech, Inc. (NASDAQ: MRNA), a leading RNAi-based drug discovery and development company, today presented data outlining a major breakthrough for the Company's Di-Alkylated Amino Acid (DiLA²)-based delivery platform with new compositions demonstrating a 10-fold improvement in the efficiency of siRNA delivery and an accompanying ~30-fold therapeutic window. The data were presented at the Informa Life Science 11th Annual Conference, EuroTIDES, taking place in Barcelona, Spain, as part of a presentation entitled "UsiRNAs and DiLA²-based delivery for RNAi Therapeutics in Oncology," by Michael V. Templin, Ph.D., Senior Vice President of Preclinical Development at Marina Biotech.

"This achievement is a testament to the success of our in-house exploratory efforts as well as experience and knowledge we've gained from our early collaborative efforts," stated J. Michael French, President and CEO of Marina Biotech. "This breakthrough in our delivery capability further strengthens our RNAi drug discovery platform as well as our continuing discussions with potential pharma partners."

Researchers at Marina Biotech identified new DiLA²-based formulations composed of multiple DiLA² molecules, that when paired with a UsiRNA targeting FVII mRNA in liver (hepatocytes) of mice, provided 50% inhibition (ED₅₀) of FVII protein activity with a single systemically delivered dose of approximately 30 micrograms/kg. In comparison, previous formulations provided ED₅₀'s of approximately 300 micrograms/kg. This effective dosing was accompanied by an approximately 30-fold therapeutic window.

"This advancement in siRNA delivery efficiency, and the speed at which we were able to achieve it, validates our research team's approach of integrating chemistry, molecular pharmaceutics, and biology to address the challenges of siRNA delivery, and continues to demonstrate the utility and diversity of our DiLA² delivery platform," stated Barry Polisky, Ph.D., Chief Scientific Officer of Marina Biotech. "Our team has established a set of assays and a systematic approach to explore the large formulation space provided by the DiLA² platform. It was through this systematic approach that we were able to quickly achieve 10-fold improvements in delivery efficiency over a three month period. We expect to further enhance the delivery capabilities of the platform, in particular, the identification of formulations for oncology specific indications."

Effective delivery is one of the key challenges for the development of RNAi-based therapeutics, and Marina Biotech is a leader in siRNA delivery with its proprietary DiLA² delivery platform and extensive research expertise in formulation screening and process development. The versatility of the DiLA² platform provides for a rapid and scientifically robust process for improving the delivery characteristics of novel formulations to meet the specific requirements of a particular therapeutic application, i.e., administration via systemic or local delivery. In recent months, advanced and improved DiLA²-based delivery formulations have been developed by expanding our delivery capabilities to include both ionizable and amphoteric compositions. The ionizable compositions are based on DiLA² molecules that demonstrate a pH-dependent phase transition across the physiological pH range to enable effective siRNA delivery inside the cell. Amphoteric compositions rely on the combination of a DiLA² molecule and another component, to mediate this pH-dependent transition. In addition to research advancements, the development teams at Marina Biotech are focused on the long term commercial requirements for RNAi-based therapeutics such as scale-up, manufacturing and cost-of-goods.

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 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:

Contact:
Marina Biotech, Inc.
Pete Garcia
Chief Financial Officer
(425) 908-3603