Idera Pharmaceuticals, Inc. Amends HYB2055 Phase 2 Renal Cell Carcinoma Protocol

CAMBRIDGE, Mass., Oct. 20 /PRNewswire-FirstCall/ -- Idera Pharmaceuticals, Inc. announced today that it has submitted to the U.S. Food & Drug Administration a protocol amendment for its ongoing Phase 2 trial of HYB2055 in patients with metastatic or recurrent clear cell renal carcinoma. The Company submitted the amendment in response to a higher than expected enrollment rate of treatment-naive patients in the Phase 2 trial. The amendment provides for enrollment of up to 23 treatment-naive patients at each of the two dose levels being used in the trial, in addition to the 23 second- line patients per dose level described in the original study design. HYB2055 (also known as IMO-2055 or IMOxine(R)) is Idera's lead Toll-like Receptor 9 (TLR9) agonist for the treatment of cancer and is based on Idera's proprietary Immune Modulatory Oligonucleotide (IMO(TM)) technology.

"Our original goal for stage A of the trial was to enroll approximately 50 patients to meet the requirement for 23 second-line patients in each of the two dose groups," said Tim Sullivan, Vice President of Development Programs at Idera. "We have 22 active U.S. sites and 52 patients have been enrolled through October 14, 2005. Over 40% of these patients are treatment naive, which is markedly higher than we anticipated. As a result, we have submitted the protocol amendment and plan to continue Phase 2 stage A patient recruitment into the first half of 2006 as we seek to accrue sufficient numbers of both treatment-naive and second-line patients to meet the statistical design. We plan to use the Phase 2 stage A data in the design of appropriate follow-up trials."

About HYB2055

HYB2055 (also known as IMO-2055 or IMOxine(R)) is Idera's lead Toll-like Receptor 9 (TLR9) agonist for the treatment of cancer and is based on Idera's proprietary Immune Modulatory Oligonucleotide (IMO(TM)) technology. The Company conducted a Phase 1 clinical trial of HYB2055 at Georgetown University Medical Center, Washington, D.C., which was reported at ASCO 2005 (Abstract 2503). As described in this press release, patient enrollment is ongoing for a Phase 2 multi-center, open-label study of HYB2055 for injection in patients with metastatic or locally recurrent clear cell renal carcinoma. The primary objective is to determine tumor response by RECIST (Response Evaluation Criteria in Solid Tumors). Secondary objectives are safety, duration of response, time to progression, survival one year after the last HYB2055 dose, and effect on quality of life. The Company is planning additional trials for HYB2055 in non-small cell lung cancer (NSCLC) patients.

About Toll-like Receptors (TLRs)

Toll-like Receptors are immune system receptors that recognize elements of pathogens such as bacteria and trigger a defensive immune response. Idera's IMO compounds mimic bacterial DNA and are specifically identified by TLR9. When TLR9 is activated, it stimulates a response that involves multiple immune system components acting to fight disease through both innate and adaptive immunity. Idera's IMO drug candidates have potential applications in a wide variety of diseases, including cancer, infectious diseases and asthma/allergies, and can be used in combination with vaccines.

About Idera Pharmaceuticals, Inc.

Idera Pharmaceuticals, Inc. is a biotechnology company focused on the discovery, development, and commercialization of targeted immune therapies based on modulation of Toll-like receptors. Idera has identified novel chemical entities that modulate immune responses through interactions with TLR9. The Company continues to identify new drug candidates specific to various diseases, including cancer, infectious diseases and asthma/allergies, based on the differentiated biological activities of its proprietary compounds. The Company's website is located at http://www.iderapharma.com.

Idera Pharmaceuticals is based in Cambridge, Massachusetts. Idera's lead candidate is HYB2055, also known as IMO-2055, a TLR9 agonist currently in Phase 2 clinical testing for cancer. Idera is also collaborating with Novartis for the discovery, development, and commercialization of IMO drug candidates targeting asthma and allergies.

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 products based on Idera's technology such as HYB2055 will advance 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 the Company will complete enrollment of the trial in the time expected; whether the FDA will comment on the revised protocol for HYB2055; whether, if the Company's products such as HYB2055 receive approval, they will be successfully distributed and marketed; whether Idera's cash resources will be sufficient to fund product development and clinical trials; and such other important factors as are set forth under the caption "Risk Factors" in Idera's Quarterly Report on Form 10-Q filed on August 9, 2005, which important factors are incorporated herein by reference. Idera disclaims any intention or obligation to update any forward-looking statements.

Contacts: Idera Pharmaceuticals, Inc. MacDougall Biomedical Communications 617-679-5500, x5526 508-647-0209 x12 Tim Sullivan Douglas MacDougall E-mail: tsullivan@iderapharma.com

Idera Pharmaceuticals, Inc.

CONTACT: Tim Sullivan of Idera Pharmaceuticals, Inc., +1-617-679-5500, ext5526, tsullivan@iderapharma.com; or Douglas MacDougall of MacDougallBiomedical Communications, +1-508-647-0209 ext. 12

Web site: http://www.iderapharma.com/