Selling a generic version of a drug under patent dispute is one tactic that generic companies have been using in the high-stakes competition between generic drug manufacturers and major pharmaceutical companies. As with the case of Cephalon (NASDAQ:CEPH) earlier in the year, disputes over the length of time a patent grants drug exclusivity frequently get settled outside of court, but not always.

One particularly bold generic drug manufacturer, Apotex Pharmaceuticals, at least temporarily lost in its attempt to outmaneuver pharmaceutical giants and partners Sanofi-Aventis (NYSE:SNY) and Bristol-Myers Squibb (NYSE:BMY), and commence selling a generic version of their blockbuster blood thinner drug, Plavix.

Yesterday Sanofi and Bristol-Myers won a temporary injunction in court ordering Apotex to immediately stop selling its generic version of Plavix. This is big news for the companies, since in just the first half of 2006 Plavix has generated over $2 billion in sales for Sanofi and Bristol-Myers.

What's interesting about this case is that earlier in the year Apotex and the pharmaceutical companies came to an agreement whereby Apotex would hold off on selling generic Plavix until 2011 in exchange for a lump sum payment of at least $40 million, but the agreement was rejected by state attorneys general on anticompetitive grounds. This failure of the agreement with Sanofi and Bristol-Myers is what prompted Apotex to start selling its generic version of Plavix in early August.

The temporary injunction against Apotex wasn't all good news for Sanofi and Bristol-Myers, though. The judge did allow existing amounts of the drug already distributed to remain on the market, and a trial is set to begin on January 22 to permanently resolve the issue of the disputed Plavix patents.

Probably fearing this sort of ruling, in less than a month, distributors had accumulated enough of the generic Plavix to last through the end of 2006. Based partly on this glut of generic Plavix that will remain in the market, yesterday Sanofi revised its earnings per share growth for the year from 12% to 2%.

When billions of dollars in revenues are on the line, drug companies will sometimes try anything to extend the time that they can market their drugs. Whether the disputed patents that grant marketing exclusivity to Sanofi and Bristol-Myers are valid or not will be determined soon enough. When the courts have to intervene to solve these disagreements, though, the only real winners are the patent lawyers.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article and welcomes your feedback. The Motley Fool has a disclosure policy .