Pfizer to Sue India's Ranbaxy Over Accupril Antihypertensive

Senior company sources at the US arm of Indian generics maker Ranbaxy have confirmed that a lawsuit has been filed by US drug major Pfizer relating to its version of antihypertensive agent Accupril (quinapril). The suit claims that Ranbaxy infringed a process patent held by Pfizer unit Parke-Davis, reportedly by using a stabilisation technique including lactose and microcrystalline cellulose.

Ranbaxy produces the drug under a deal with Israeli generics major Teva, which exclusively markets the product in the US. Teva's challenge to the process patent on quinapril, which is not due to expire until 2007, was defeated, but the Israeli company pressed ahead with a launch in December 2004, with an appeal against the decision still ongoing. The generic version of quinapril is now understood to have captured a US market share of roughly 40 percent, implying revenue of approximately US$220mn. Notably, Ranbaxy has recently challenged Pfizer on its patent for best-selling cholesterol drug Lipitor.