“During the first three years of our agreement, scientists at Idera and Merck have created a large portfolio of novel agonists of TLRs 7, 8, and 9 using Idera’s chemistry-based approach together with Merck’s innovations in chemistry and adjuvant formulation,” said Tim Sullivan, Ph.D., Vice President of Development Programs at Idera. “We look forward to continued studies with selected TLR agonist candidates as vaccine adjuvants.”

“Throughout this collaboration, scientists at Merck and Idera have collaborated closely to characterize novel TLR agonists as adjuvant candidates,” said Amy Espeseth, Ph.D., Director of Virology and Vaccines, Worldwide External Basic Research, Merck Research Laboratories. “We look forward to continued progress on the program.”

Merck and Idera scientists have made several data presentations and publications based on the work conducted under this research and development collaboration.

About Idera Pharmaceuticals, Inc.

Idera Pharmaceuticals develops drug candidates to treat infectious diseases, autoimmune and inflammatory diseases, cancer, and respiratory diseases, and for use as vaccine adjuvants. Our proprietary drug candidates are designed to modulate specific Toll-like Receptors, which are a family of immune system receptors that direct immune system responses. Our pioneering DNA and RNA chemistry expertise enables us to create drug candidates for internal development and generates opportunities for multiple collaborative alliances. For more information, visit 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 the Company's actual results to differ materially from those indicated by such forward-looking statements, including whether results obtained in early clinical studies or in preclinical studies such as the studies referred to above will be indicative of results obtained in future clinical trials or warrant additional trials; whether products based on the Company'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 with Merck KGaA and an affiliate of Merck & Co., Inc. will be successful; whether the patents and patent applications owned or licensed by the Company will protect the Company’s technology and prevent others from infringing it; whether the Company's cash resources will be sufficient to fund the its 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 three months ended September 30, 2009, which important factors are incorporated herein by reference. The Company disclaims any intention or obligation to update any forward-looking statements.

Contact:

Idera Pharmaceuticals, Inc. Kelly Luethje, 617-679-5519 kluethje@iderapharma.com or MacDougall Biomedical Communications Chris Erdman, 781-235-3060 cerdman@macbiocom.com