Exhibit 16.1 Office of the Chief Accountant Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 April 30, 2002 Dear Sir/Madam: We have read the second paragraph of Item 4 included in the Form 8-K dated April 30, 2002 of Curis, Inc. to be filed with the Securities and Exchange Commission and are in agreement with the statements contained therein. Very truly yours, Arthur Andersen LLP cc: Mr. George Eldridge, Chief Financial Officer, Curis, Inc.