Nexium is the company's top-seller, bringing in revenue of $3.8 billion in 2004. AstraZeneca, the U.K.'s No. 2 drugmaker, is already fighting a challenge to Nexium from Hyderabad, India-based Dr. Reddy's Laboratories Ltd. Nexium was introduced to replace Losec [Prilosec], once the world's best-selling drug before its patent protection expired in October 2001.
Ranbaxy asked the U.S. Food and Drug Administration to allow it to sell 20 milligram and 40 milligram capsules, whose patents expire in 2018, London-based AstraZeneca said Oct. 18.
[Ranbaxy is also challenging Pfizer over the patent to its anti-cholesterol drug Lipitor, the world's best-selling prescription medicine. A decision by the district court in this case is expected soon.]
At the end of September, Astra stated that Teva Pharmaceuticals, an Israel based drugs firm was challenging its patent rights to Seroquel, another of its blockbuster drugs which notched up sales of $2 billion last year. Teva filed an abbreviated new drug application (ANDA) in the US as a challenge to Seroquel, giving Astra a 45-day period in which to file a legal claim against it. Astra maintained in this case as well, that it had "full confidence" in its ownership of the intellectual property rights to the drug.