Exhibit 99.1 ------------ [LETTERHEAD OF ARTHUR ANDERSEN] June 27, 2002 Securities and Exchange Commission Judiciary Plaza 450th Fifth Street, N.W. Washington, D.C. 20549 Ladies and Gentlemen: We have read and agree with the comments in Part III of the Form 12b-25, dated on or about June 27, 2002, of CeNeS Pharmaceuticals plc for the fiscal year ended December 31, 2001. Yours truly, /s/ Arthur Andersen Arthur Andersen