John Butler Senior Vice President; President, Renal, Endocrinology & Cardiovascular John Butler joined Genzyme in 1997 as product manager for Renagel. His current responsibilities include managing all aspects of the company's renal business, including Renagel, Renvela, and Hectorol, as well as managing development of the renal portfolio. He also has responsibility for the endocrinology and cardiovascular business units. Mr. Butler has also served as vice president of strategic planning and vice president of Renagel Europe. Prior to joining Genzyme, he worked in sales and marketing at Amgen Inc. Mr. Butler has an M.B.A. from Baruch College and a B.A. from Manhattan College.