Idera Pharmaceuticals Presents Data in Preclinical Models of Lymphoma on IMO-4200, a Dual Agonist of TLRs 7 and 8, at the American Society for Hematology Meeting

Idera Pharmaceuticals (Nasdaq: IDRA) today announced that it presented new data showing that IMO-4200, a dual agonist of Toll-like receptor (TLR) 7 and TLR8, in combination with approved cancer treatments increased antitumor activity in preclinical models of lymphoma. The presentation by Idera scientists, entitled "IMO-4200, a novel TLR7 and TLR8 dual agonist, enhances antitumor effect of ofatumumab, rituximab and cytotoxics in preclinical models of hematological malignancies”, abstract number 3724, was made at the 53^rd annual meeting of the American Society for Hematology being held in San Diego, California December 11-13, 2011.

"The data presented show that IMO-4200 provides a novel scientific rationale for the targeted immunotherapy of hematological malignancies,” said Nicola La Monica, Ph.D., VP of Biology of Idera Pharmaceuticals. "IMO-4200 has shown to potentiate the anti-cancer activity of a broad range of approved agents, including rituximab, bortezomib and ofatumumab, in preclinical models of lymphoma.”

In the data presented today, IMO-4200 was evaluated in preclinical cell-based assays and in combination with approved cancer therapy agents in mouse models of lymphoma.

• IMO-4200 in combination with ofatumumab, an anti-CD20 antibody, resulted in:
  • improved antitumor activity
  • increased survival compared to treatment with either agent alone
  • enhancement of complement-dependent cytotoxicity, a mechanism by which ofatumumab exerts its antitumor effect
• IMO-4200 in combination with rituximab, an anti-CD20 antibody, and fludarabine or IMO-4200 in combination with rituximab and bendamustine resulted in:
  • improved antitumor activity
  • increased survival
  • enhanced clearance of circulating tumor cells
  • greater antibody-dependent cell cytotoxicity, a mechanism by which rituximab exerts its effect

Authors of the presentation were Daqing Wang, Ph.D., Melissa Precopio, Ph.D., Michael J. Reardon, Ph.D., Tao Lan Ph.D., Jimmy X. Tang, Ekambar R. Kandimalla, Ph.D., Alice Bexon M.D., Nicola La Monica, Ph.D. and Sudhir Agrawal, D. Phil.

About IMO-4200

IMO-4200 is a novel synthetic RNA-based dual agonist of TLR7 and TLR8 identified as a lead drug candidate for the treatment of hematological malignancies. IMO-4200 is designed to stimulate immune responses mediated through TLR7 and TLR8, which are expressed in human dendritic cells, B-cells, monocytes, and macrophages. In preclinical mouse models of cancer, IMO-4200 has shown anticancer activity involving both innate and adaptive immune responses. IMO-4200, when administered in combination with approved cancer therapy drugs, rituximab, ofatumumab or bortezomib, showed significantly increased antitumor activity compared to the single-agent effects in several preclinical lymphoma models.

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 results from preclinical studies such as the results described in this release will be indicative of results obtained in later preclinical or clinical trial; 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.