AstraZeneca sues Ranbaxy on Nexium patent

New Delhi: Global drug company AstraZeneca, today said it had filed a lawsuit in the United States District Court of New Jersey against drug maker Ranbaxy Laboratories for what Astra Zeneca calls 'wilful infringement' of its patent for Esom eprazole magnesium (marketed as Nexium), a drug that relieves acidity and heartburn.

The company said it filed the lawsuit in response to the abbreviated new drug application (ANDA) filed by Ranbaxy Laboratories with the US Food and Drug Administration with the intention of marketing a generic version of the $4-billion-a-year drug Nexium before the expiry of six of its patents.

AstraZeneca's patents - 5,714,504; 5,877,192; 6,369,085; 6,428,810, 6,875,872 and 5,948,789 - are due to expire from 2014 onwards through to 2019, the statement said. AstraZeneca said it would continue vigorously to defend and enforce its intellectual property rights protecting Nexium.

Nexium is prescribed for gastro-oesophageal reflux, also called heartburn or acid reflux. Ranbaxy officials were not available for comment.

The lawsuit, filed in the U.S. District Court for the District of New Jersey, automatically bars the US Food and Drug Administration from approving Ranbaxy's application for 30 months, or until an adverse court decision.

The generic challenge to Nexium was anticipated, and is a setback for AstraZeneca. In recent times many of Astra Zeneca's drugs have gone off patent leading generic drug makers from countries like Israel and India to move in. AstraZeneca says it is looking out to buy medicines in late-stage clinical trials to beef up the firm's drugs pipeline.

Ranbaxy's decision to take on AstraZeneca over Nexium is another high-profile gamble by the Indian company, fast gaining a reputation as one of the most aggressive challengers to patents held by big pharmaceutical companies. Ranbaxy says it can produce cheap forms of both the 20 milligram and 40 mg Nexium capsules.

Nexium has been a huge commercial success for AstraZeneca and analysts expect its sales to touch $5.5 billion in 2005.