EXHIBIT 4.15 THIS DEBENTURE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAW, AND MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR OTHERWISE DISPOSED OF UNLESS A REGISTRATION STATEMENT UNDER SUCH ACT...Debenture Agreement • November 13th, 1998 • Genzyme Corp • Biological products, (no disgnostic substances) • New York
