Mylan, Pfizer Launch Generic Norvasc

Last week's reversal of a district court ruling that blocked a challenge to a key Norvasc patent has triggered an early generic launch of the drug by Mylan Laboratories. The move prompted Pfizer to then introduce its own generic Norvasc.

The ruling negated Pfizer's six months of pediatric exclusivity for its blockbuster hypertension treatment, which went off patent March 25.

Industry analysts had predicted sales of the drug in generic form could begin immediately due to the invalidation of the '303 patent covering amlodipine besylate, the active ingredient in Norvasc. Last week the U.S. Court of Appeals for the Federal Circuit struck down that patent and found it to be invalid and unenforceable.

Mylan immediately launched amlodipine besylate in 2.5- and 10-mg tablets with 180 days of marketing exclusivity, as it was the first generic firm to file on all strengths of amlodipine, the company said.

In response to Mylan's launch, Pfizer said it will immediately make available its own generic version of amlodipine besylate through its subsidiary Greenstone.

Pfizer said it would continue to pursue all available legal remedies to protect the market for Norvasc through the six-month pediatric exclusivity period, which ends in September.

Norvasc generated approximately $2.7 billion in U.S. sales in 2006, according to IMS Health, and it is the most prescribed hypertension drug in the world, according to Pfizer.