Marina Biotech, Inc. (Formerly Known as MDRNA, Inc.) Announces Interim Safety Results of Long-Term Toxicology Study

BOTHELL, WA--(Marketwire - October 26, 2010) - Marina Biotech, Inc. (NASDAQ: MRNA), a leading RNAi-based drug discovery and development company, today announced interim results of a six month non-human primate toxicology study with clinical candidate CEQ508. CEQ508 was administered in an oral suspension once daily to non-human primates for over 180 consecutive days at a dose level of 10(11) colony forming units (cfu)/day. During this period of time, no toxicity or test article related adverse events were observed. To support the potential requirements of a Phase 2 clinical trial, the non-human primate study was extended for an additional three months. CEQ508 is Marina Biotech's clinical candidate for the treatment of Familial Adenomatous Polyposis (FAP), and is expected to begin dosing in patients in a Phase 1b/2a trial this quarter.

"These interim results and the completion of the full nine month safety study in non-human primates demonstrates the potential for the long term treatment of patients with our novel RNAi-based therapeutic," said J. Michael French, President & CEO of Marina Biotech. "CEQ508 is Marina Biotech's first drug candidate to reach human clinical trials. We're very excited to begin the clinical trial and look forward to quickly advancing this drug to the market and providing a necessary therapeutic to a patient population in need."

CEQ508 is the first drug candidate in a novel class of therapeutic agents utilizing the transkingdom RNA interference (tkRNAi) platform. CEQ508 is comprised of attenuated bacteria that are engineered to enter into dysplastic tissue and release a payload of short-hairpin RNA (shRNA), a mediator in the RNAi pathway. The shRNA targets the mRNA of β-catenin, which is known to be dysregulated in classical FAP. CEQ508 is being developed as an orally administered treatment to reduce the levels of β-catenin protein in the epithelial cells of the small and large intestine. The Phase 1b/2a clinical trial will be conducted in patients with FAP at Massachusetts General Hospital, Boston, Massachusetts. For more information please contact clinicaltrials@marinabiotech.com.

About FAP

CEQ508 is being developed for the treatment of Familial Adenomatous Polyposis (FAP), a hereditary condition that occurs in approximately 1:10,000 persons worldwide. FAP is caused by mutations in the Adenomatous Polyposis Coli (APC) gene. As a result of these mutations, epithelial cells lining the intestinal tract have increased levels of the protein β-catenin, which in turn, results in uncontrolled cell growth. Proliferation of the epithelial cells results in the formation of numerous (hundreds to thousands) non-cancerous growths (polyps) throughout the large intestine. By age 35, 95% of individuals with FAP have developed polyps and most will experience adverse effects including increased risk of bleeding and the potential for anemia. In more severe cases, obstruction of the intestines, abdominal pain, and severe bouts of diarrhea or constipation can occur. FAP patients are also at an increased risk of various cancers, the most concerning of which is a nearly 100% occurrence of colon cancer if measures are not taken to prevent the formation of polyps. For many patients, complete colectomy (surgical removal of the entire large intestine), usually performed in the late teenage years or early twenties, is the only viable option for treatment. However, surgical intervention is not curative as the risk of polyps forming in the remaining portions of the intestinal tract and in the small intestine continues after colectomy.

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.