United States securities and exchange commission logo March 9, 2021 Vincent J. Milano President and Chief Executive Officer Idera Pharmaceuticals, Inc. 505 Eagleview Blvd., Suite 212 Exton, Pennsylvania 19341 Re: Idera Pharmaceuticals, Inc. Registration Statement on Form S-3 Filed March 3, 2021 File No. 333-253804 Dear Mr. Milano: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Abby Adams at (202) 551-6902 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Joanne R. Soslow, Esq.