Marina Biotech Announces That Licensee ProNAi Therapeutics Reported Phase 1 Study Results Using SMARTICLES(R) Nucleic Acid Delivery Technology

BOTHELL, WA--(Marketwire - Dec 5, 2012) - Marina Biotech, Inc. (PINKSHEETS: MRNA), a leading nucleic acid-based drug discovery and development company, today announced that the Company's licensee, ProNAi Therapeutics, has reported results of their Phase 1 study of PNT2258, an anti-Bcl-2 cancer drug which uses the Company's SMARTICLES delivery technology. PNT2258 targets Bcl-2-driven tumors such as diffuse large B-cell lymphoma, follicular lymphoma and chronic lymphocytic leukemia. The data were presented at the annual Symposium on Molecular Targets and Cancer Therapeutics jointly hosted by the European Organization for Research and Treatment of Cancer, The National Cancer Institute and the American Association for Cancer Research.

ProNAi Therapeutics reported statistically significant, dose-dependent, and specific knockdown of the Bcl-2 gene with suppression of protein levels up to 60 percent. Patients received the drug for extended periods of time without having material side effects as seen with other anti-Bcl-2 drugs or nucleic acid cancer drugs in development. The results indicate that the drug can be administered as either a single agent or potentially in combination with other anti-cancer drugs without increasing patient side effects.

"We are pleased to see the results of this ground breaking clinical trial using our SMARTICLES delivery technology," stated Richard Ho, M.D., Ph.D., Executive Vice President, Research and Development at Marina Biotech. "The results suggest that SMARTICLES efficiently and effectively delivers an oligonucleotide to tumor cells with good safety and tolerability. We look forward to ProNAi's continued advancement of this program and the validation of our broad nucleic acid-based drug discovery platform."

PNT2258 was evaluated in an open-label, single arm, Phase I dose-escalation study in patients with advanced solid tumors for which no standard therapy exists at START in San Antonio Texas. PNT2258 is ProNAi's first drug candidate from its DNA interference drug platform. Patients receive PNT2258 as an intravenous infusion once daily for 5 consecutive days (Days 1-5) of every 21-day cycle (3 weeks).

About Amphoteric Liposomes

Amphoteric liposomes define a novel class of liposomes, which are pH dependent charge-transitioning particles that provide for the delivery of a nucleic acid payload (e.g., siRNA, microRNA, antisense, decoy, etc.) to cells either by local or systemic administration. Amphoteric liposomes are designed to release their nucleic acid payload within the target cell where the nucleic acid can then engage a number of biological pathways, including the RNA interference pathway, and thereby exert a therapeutic effect. Currently, Marina Biotech amphoteric liposomal delivery technology includes non-DiLA2 based amphoteric liposomes (or SMARTICLES®) and DiLA2 based amphoteric liposomes.

About Marina Biotech, Inc.

Marina Biotech is a biotechnology company focused on the development and commercialization of oligonucleotide-based therapeutics utilizing multiple mechanisms of action including RNA interference (RNAi) and messenger RNA translational blocking. The Marina Biotech pipeline currently includes a clinical program in Familial Adenomatous Polyposis (a precancerous syndrome) and two preclinical programs -- in bladder cancer and myotonic dystrophy. Marina Biotech has entered into an agreement with both Mirna Therapeutics and ProNAi Therapeutics to license Marina Biotech's SMARTICLES® technology for the delivery of microRNA mimics and DNAi, respectively. In addition, Marina Biotech announced exclusive licensing agreements with Monsanto Company for Marina Biotech's delivery and chemistry technologies and with Girindus America for the supply of CRN-based oligonucleotides. Marina Biotech recently entered into non-exclusive agreements with Novartis Institutes for Biomedical Research and Tekmira Pharmaceuticals to license Marina Biotech's CRN and UNA nucleic acid modification chemistries, respectively. Marina Biotech's goal is to improve human health through the development of RNAi- and oligonucleotide-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 in the near term; (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 prior to, and 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.