Sanofi-Aventis has strongly denied it has ever offered a higher price for the US biotech firm Genzyme.
Genzyme has said the chief executive of the French pharmaceuticals giant floated the possibility of paying as much as $80 a share at a meeting in September.
Sanofi’s offer in its hostile takeover bid is $69 a share.
Analysts say Sanofi will almost certainly have to raise its bid.
Investors obviously think there will a higher offer as Genzyme’s shares have been above $73.