Wyeth Pharmaceuticals Inc is seeking $960 million in damages from Sun Pharmaceutical Industries for alleged patent infringement in launching a generic version of acid reflux drug Protonix in the US, the company said on Thursday.
The original patent relating to Protonix, known chemically as pantoprazole sodium, is held by Swiss drug maker Nycomed and was licensed to Wyeth, which is now owned by Pfizer.
Wyeth and Nycomed, owned by Japan's Takeda Pharmaceutical Co, filed the lawsuit in the US District Court in New Jersey against Sun and Teva Pharmaceutical Industries.
Sun launched its generic version of Protonix tablets in January 2008 after Teva Pharmaceutical Industries and its US subsidiary began selling the drug in December 2007.
"Sun Pharma believes that it has sound reasons to disagree with these overstated claims of Wyeth, and also continues to believe that the patent is invalid and unenforceable and will pursue all available legal remedies including appeals," the company said on Thursday.
Nycomed manufactures a major quantity of pantoprazole in a joint venture with India's Cadila Healthcare. Drugs, in which pantoprazole is a key ingredient, have annual global sales of between $7 billion and $8 billion.
Reacting to the news, the company's shares opened the day on a bearish note and finally ended at Rs 542, down 2.5% on the Bombay Stock Exchange. On the NSE also, the stock settled 2.8% lower at Rs 541.