Genzyme Said to Rebuff Sanofi-Aventis Buyout Approach

Genzyme Corp., the world’s largest maker of drugs for rare genetic diseases, rebuffed Sanofi-Aventis SA’s takeover approach last week, two people with knowledge of the matter said today.

Genzyme can command at least $22 billion, or $80 a share, on the potential for revenue to surge after the company resolves manufacturing defects depressing sales of existing products and introduces new medicines, investors and analysts said today. That is a 48 percent premium over Genzyme’s closing price on July 22, the day before reports of Sanofi’s interest.