Future Looks Grim for Bristol-Myers

Updated from 11:57 a.m. EDT

A Canadian company has started shipping a generic version of Bristol-Myers Squibb's (BMY Quote) biggest product, placing the New York drugmaker's sales, profit and dividend at risk of being substantially lowered.

Apotex, a privately held company, said Tuesday that it began selling copies of the anticoagulant Plavix even though it's being sued for patent infringement by Bristol-Myers, which holds the U.S. marketing rights to the drug, and Sanofi-Aventis (SNY Quote), its developer.

"We are confident that the patent will be held invalid," said Barry Sherman, chief executive of Apotex. Bristol-Myers and Sanofi-Aventis said they will "vigorously pursue enforcement" of their patent rights.

Shares of Bristol dropped $1.56, or 6.9%, to $21.21. The stock sank as low as $20.85. Volume exceeded 64 million shares, or more than eight times the daily average for the past three months. Sanofi-Aventis was down 41 cents, or 0.9%, to $44.45 on volume that was triple the average.

"At this point, it is too early to determine what effect this action by Apotex could have on the Plavix business," said Peter Dolan, CEO of Bristol-Myers, in a message to employees. "You should know, however, that we have contingency plans in place to mitigate the impact."

Still, Dolan added that he's concerned "about the negative implications [the Apotex action] will have for patients. Bristol-Myers Squibb and Sanofi-Aventis have a long-term R&D plan for Plavix that cannot be sustained if we no longer have exclusivity for this product."

Plavix accounted for $3.8 billion of Bristol's sales last year, or 20% of the total. France's Sanofi-Aventis collected sales of $2.45 billion from the drug, or 7.4% of its total revenue.

At least two investment banking firms cut their ratings on Bristol to sell, including A.G. Edwards. Analyst Albert Rauch, who had been neutral on the stock, told clients that he expects Bristol-Myers' dividend to be sliced in half.