French pharmaceutical group Sanofi-Aventis said Monday it was to acquire Chattem of the United States for for 1.9 billion dollars, creating the world's fifth largest consumer health care company. 'The acquisition of Chattem will be a significant milestone in Sanofi-Aventis' transformation strategy and will provide us with the ideal platform in the US healthcare market, which represents 25 percent of the current worldwide opportunity,' said Sanofi-Aventis chief executive Christopher Viehbacher. Chattem, founded 130 years ago, is 'a leading manufacturer and marketer of branded consumer healthcare products, toiletries and dietary supplements ... in the United States,' a joint statement said. Its brands include itch relief cream Cortizone-10 and Selsun Blue dandruff shampoo. Under the transaction, which has been approved by Chattem's board of directors, Sanofi-Aventis would acquire 100 percent of outstanding Chattem shares in a cash offer worth 93.50 dollars a share, or 1.9 billion dollars (1.3 billion euros). The tender offer is to begin in January, with the companies expecting the deal to be completed in the first quarter of 2010. The statement said the offer price of 93.50 dollars a share represented a 34 percent premium on Chattem's closing share price on December 18. 