Pfizer Files Lawsuit to Block Generic Caduet

Three years after launching Caduet, a combination of two blockbuster drugs some say is designed to extend patent life, Pfizer is in litigation to block a generic version of the drug.

In a complaint recently filed in the U.S. District Court for the District of Delaware, Pfizer said the generic version of its drug proposed by Ranbaxy would infringe on patents it owns covering key ingredients needed to produce the drug.

Caduet combines the active ingredients in two of Pfizer's top-selling drugs -- its cholesterol drug Lipitor (atorvastatin calcium) and its hypertension drug Norvasc (amlodipine besylate). It won FDA approval in 2004.

Ranbaxy, in its abbreviated new drug application with a Paragraph IV certification, challenged patents '893 and '574, key patents held by Pfizer regarding its combination drug.

"We challenged [the patents] based on the fact that we believe, after due consideration, that they are invalid or not infringed," a Ranbaxy spokesman said.

Although Pfizer holds several patents covering Caduet in addition to patent claims covering the same ingredients for Lipitor and Norvasc, company spokesman Bryant Haskins disregarded notions by some in the industry who believe the combination drug may have been designed to extend patent life to ward off generic competition.

"[We] are treating several conditions at the same time with this drug. You get more from the combination drug than from each individual drug," Haskins said.