Sanofi-Aventis' position remains unchanged regarding a $18.5 billion hostile offer for Genzyme, Sanofi Chief Executive Chris Viehbacher told Reuters on the sidelines of the Women's Forum.

"Our position was made very clear at the time we made the offer and nothing's changed," said Viehbacher on Thursday when asked if anything had altered in his position since Sanofi denied floating the idea of an $80 per share offer for the U.S. biotech.

On Oct. 4, Sanofi-Aventis went directly to Genzyme shareholders with a cash offer of $69 a share, after Genzyme refused to open its books to friendly merger talks dismissing Sanofi's initial offer as
too low.

Three days later, Genzyme's CEO Henri Termeer said in a regulatory filing that Viehbacher proposed a deal price range of $69 to $80 per share at a joint CEO meeting in late September, two weeks before it went hostile.

Since news of Sanofi's interest in Genzyme emerged, the rhetoric between Termeer and Viehbacher has ratcheted up. The exchanges could affect how quickly any deal would be resolved, with a hostile campaign likely to last well into next year.

France's Sanofi wants to acquire U.S.-based Genzyme's lucrative portfolio of drugs for rare diseases as it prepares for the loss of patent protection on top-selling drugs, such as its biggest product, the blood clot preventer, Plavix.