Idera Announces Presentation on Preclinical Studies of TLR Antagonist Candidate in Models of Atherosclerosis at American Heart Association Scientific Sessions 2011

Idera Pharmaceuticals, Inc. (Nasdaq: IDRA) today announced the presentation of preclinical data indicating that its dual antagonist of Toll-like receptor (TLR) 7 and TLR9 reduced restenosis and atherosclerosis in a mouse model of hypercholesterolemia. The studies were conducted in collaboration with Professor Paul Quax, Ph.D., from the Department of Surgery, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, the Netherlands. The oral presentation, entitled "TLR7/9 activation enhances neointima formation in hypercholesterolemic APOE*3Leiden mice,” was made at the American Heart Association (AHA) Scientific Sessions 2011 held in Orlando, FL.

"There is a growing body of evidence that inflammation plays a significant role in cardiac diseases and antagonism of TLRs may interrupt these inflammatory processes,” commented Professor Quax. "By inhibiting TLR7 and TLR9, we were able to reduce inflammation and limit vascular remodeling in a preclinical model. These new preclinical data offer promising in vivo results pointing to a potential therapeutic benefit of TLR7 and TLR9 antagonists in restenosis and accelerated atherosclerosis.”

"In addition to evaluating antagonists of TLR7 and TLR9 in autoimmune diseases, we have been conducting studies of these candidates in preclinical models of cardiovascular diseases. This presentation expands upon our prior studies, in which our TLR7 and TLR9 antagonist candidates suppressed total cholesterol in hyperlipidemic mice, as presented at AHA 2010,” said Nicola La Monica, Vice President of Biology at Idera Pharmaceuticals. "Idera’s TLR7 and TLR9 antagonist candidates have been created through a chemistry-based approach and our lead candidate, IMO-3100, is in clinical development for autoimmune diseases.”

In the present study, TLR7 and TLR9 expression was detected in femoral arteries after surgical intervention, suggesting activation by cellular stress. Formation of neointima after femoral artery cuff placement in hypercholesterolemic APOE*3Leiden mice also was observed. Neointima is a new, thickened inner layer of veins or arteries, commonly formed in patients with atherosclerosis and restenosis after balloon angioplasty. Administration of Idera’s TLR7 and TLR9 dual antagonist led to significant reduction in the formation of neointima, in signs of inflammation, and in induction of IL-10 expression.

Authors of the presentation are J.C. Karper, M.M. Ewing, K.L.L. Habets, M.R. deVries, H.A.B. Peters, J.F. Hamming, J. Kuiper, J.W. Jukema and P.H.A. Quax of Leiden University Medical Center and E.R. Kandimalla, N. La Monica, of Idera Pharmaceuticals.

About Idera Pharmaceuticals, Inc.

Idera Pharmaceuticals applies its proprietary Toll-like Receptor (TLR) drug discovery platform to create immunomodulatory drug candidates. The Company’s TLR-targeted candidates are being developed to treat autoimmune and inflammatory diseases, cancer, and for use as vaccine adjuvants. Additionally, the Company is advancing its gene-silencing oligonucleotide (GSO) technology for the purpose of inhibiting the expression of disease-promoting genes. For more information, visit http://www.iderapharma.com.

Idera Forward Looking Statements

This press release contains forward-looking statements concerning Idera Pharmaceuticals, Inc. that involve a number of risks and uncertainties. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, the words "believes," "anticipates," "plans," "expects," "estimates," "intends," "should," "could," "will," "may," and similar expressions are intended to identify forward-looking statements. There are a number of important factors that could cause Idera's actual results to differ materially from those indicated by such forward-looking statements, including whether data from preclinical studies such as the data discussed in this release will be indicative of results obtained in later preclinical studies and clinical trials; whether products based on Idera's technology will advance into or through the clinical trial process on a timely basis or at all and receive approval from the United States Food and Drug Administration or equivalent foreign regulatory agencies; whether, if the Company's products receive approval, they will be successfully distributed and marketed; whether the Company's collaborations will be successful; whether Idera's cash resources will be sufficient to fund the Company's operations; and such other important factors as are set forth under the caption "Risk Factors" in Idera's Quarterly Report on Form 10-Q for the quarter ended September 30, 2011 which important factors are incorporated herein by reference. Idera disclaims any intention or obligation to update any forward-looking statements.