Drug makers Sanofi-aventis and Bristol-Myers Squibb claimed victory Thursday, saying a federal court dismissed an appeal that sought to open Canadian markets to Apotex's generic version of their blood-thinner Plavix.

The Toronto-based Apotex had appealed a Federal Court of Canada judgment that prevented Canadian regulators from allowing the company to sell 75 milligram tablets of clopidogrel bisulfate.

That's the active ingredient in Plavix, which is sold by Sanofi-aventis, of France, and Bristol-Myers Squibb, of the United States, and is one of the top-selling drugs in the world.

The Federal Court of Appeal rejected Apotex's appeal, Sanofi-aventis and Bristol-Myers Squibb said Thursday.

The ruling was the latest hurdle thrown in front of Apotex, a privately held generic drug manufacturer, in its attempt to market the drug.

The company launched the generic drug in the United States in August, but U.S. District Judge Sidney Stein ordered a stop to future sales of it in a ruling on Aug. 31.

Stein did not order Apotex to recall any of the drug that was already in the hands of distributors.

The judge ruled against Apotex's argument that it will be able to prove the patent on Plavix was invalid. Apotex has vowed to appeal the U.S. ruling.

On the New York Stock Exchange, shares of Sanofi-aventis rose 29 cents to close at $46.33 US, while Bristol-Myers Squibb was up two cents at $26.31 US.