Drug makers facing generic rival for top-selling Plavix

Sanofi-Aventis SA and Bristol-Myers Squibb Co. are facing generic competition in the United States for their top-selling Plavix blood-thinning pill five years earlier than planned.

Apotex Inc., the closely held Canadian maker of generic drugs, said it has started shipping cheaper copies of Plavix, the world's second best-selling pill. Sanofi and Bristol-Myers lost a bid Monday in US court to block the sales.

At stake for Paris-based Sanofi and New York-based Bristol-Myers is $6.3 billion in annual revenue from the $4-a-day pill. A new generic drug may account for 90 percent of prescriptions within three months of introduction, according to IMS Health Inc., a Fairfield, Conn., provider of pharmaceutical data. Weston, Ontario-based Apotex may be subject to penalties if the patent is later upheld in court.

``Sanofi and Bristol are showing their intent to resume aggressive legal action to protect their interests," Chris Shibutani, a JPMorgan Securities Inc. analyst in New York, said in a note yesterday. ``We believe it is in all the parties' interests to move quickly, and will look for prompt movement to a full trial. We expect that a settlement at this point is very unlikely."

Bristol-Myers shares dropped $1.56, or 6.9 percent, to $21.21. The stock has lost 18 percent since July 26, the day before the drug maker disclosed a Justice Department investigation of an accord to keep the Apotex product off the market until 2011.

Plavix is Bristol-Myers's biggest product and Sanofi's second-largest. Its sales last year were second only to Pfizer Inc.'s Lipitor cholesterol pill, with $12.2 billion. The companies spent $121.4 million advertising Plavix last year in the United States, according to Nielsen Media Research.