Plavix is a prescription blood-thinning medication. It competes with several anticoagulants, as well as traditional aspirin.
Executives from Saatchi & Saatchi could not be reached.
Saatchi & Saatchi Healthcare beat out Health@ JWT, a unit of WPP Group's J. Walter Thompson; Omnicom Group's DDB Worldwide; Grey Global Group's Grey Healthcare; and Havas' Euro RSCG MVBMS Partners, all New York-based agencies.
WPP's Ogilvy & Mather resigned the business in December.
Plavix represents the second big account win for Saatchi & Saatchi Healthcare in the last four weeks. Last month, the agency won the osteoporosis drug Boniva, co-marketed by Roche and GlaxoSmithKline.