The review is for the company's prescription and over-the-counter brands.
It is being held at holding company level with WPP, Havas, Omnicom and Publicis pitching. WPP, Havas and Omnicom all own incumbent agencies.
Schering-Plough becomes the third drug-maker in the past 14 months to look at its advertising arrangements, with Sanofi-Synthelabo and AstraZeneca also reviewing.
The company is the 12th-largest pharmaceutical company in the world, with 2003 revenue of $8.3 billion. It is dwarfed by Pfizer, the world's largest drug company, which had 2003 revenue in excess of $45 billion.
Schering-Plough's biggest brand is Clarinex, which is supported with a total global promotional spend of $320 million.
According to Nielsen Media Research, the only two active Schering-Plough accounts in the UK are the hayfever relief remedy Clarityn and the Levonelle contraceptive brand. The creative for these is held by MJL, with John Ayling & Associates and MindShare handling the respective media briefs.
In 2002, however, WCRS won a pan-European brief for Schering-Plough's Coppertone brand.
The agency subsequently created a print campaign attempting to reposition the brand, which is primarily thought of as a tanning aid across most of the continent. In the US, Coppertone has a 30 per cent share of the skincare market.