EX-99.3 5 d27625_ex99-3.txt AGREEMENT TO FILE JOINTLY EXHIBIT 99.3 AGREEMENT TO FILE JOINTLY We, the undersigned, hereby express our agreement that the attached Schedule 13D is filed on behalf of each of us. AVENTIS PHARMACEUTICALS INC. Date: January 7, 2002 By: /s/Edward H. Stratemeier Edward H. Stratemeier Vice President AVENTIS HOLDINGS INC. Date: January 7, 2002 By: /s/Phillip R. Ridolphi Phillip R. Ridolphi President RHONE-POULENC RORER INC. Date: January 7, 2002 By: /s/Edward H. Stratemeier Edward H. Stratemeier Vice President