Sanofi-syntholabs tookover Aventis this summer. The merger was official in August. I am not sure why the symbol AVE is still trading (i.e., why they didn't merge into one symbol.) They are based in France.
From an Aventis press release: "Aventis S.A. is a subsidiary of Sanofi-Aventis (formerly known as Sanofi-Synthelabo)"
you can do a google search on sanofi-aventis merger for more details.
Yes, Accomplia is part of it, but as you say, it is a large company.
P.S., They are also supplying the bulk of flu vaccine to the U.S. this year after Chiron's product was rejected due to contamination. The majority of news about the flu vaccine seems to be under the AVE ticker.