Sanofi-Aventis and Bristol-Myers Squibb were celebrating after a US

appeals court upheld an injunction that stops rival Apotex from selling a

generic version of the firms’ blockbuster blood-thinner Plavix.

The decision upheld an earlier court ruling that stops sales of generic

Plavix (clopidogrel) until a judge can rule on the validity of one of the compound's patents. That trial is scheduled to start on January 22.

Sales of Plavix collapsed in the third quarter of 2006 after Canada’s

Apotex flooded the market with a six-month supply of generic clopidogrel

in August. Given that Plavix was the second biggest-seller in the world

last year, behind Pfizer’s Lipitor (atorvastatin), the effect on Sanofi

and B-MS has been dramatic.

The Plavix cases have proved particularly dramatic for B-MS, which had

earlier signed a deal with Apotex to keep its copycat version of the blood

thinner off the market in the USA until September 2011. That pact was

overturned by US regulators, prompting Apotex to launch its version anyway and, although an injunction was put in place, the Canadian firm did not have to recall its product.

Sanofi and B-MS issued a statement saying they believe that “the Apotex

generic product infringes their intellectual property rights, which they

continue to vigorously defend in the pending patent litigation.’’