US launch of Ranbaxy's Lipitor may be sooner

Pfizer's application to re-issue patent rejected.

India's leading drug maker Ranbaxy laboratories may launch the generic version of Pfizer's largest-selling cholesterol-lowering drug, Lipitor, in March 2010, about 15 months ahead of schedule, in the US market.

The chances of Ranbaxy eating into the $8.5 billion market of Lipitor in the US brightened when the US Patent and Trademark Office rejected Pfizer's application to re-issue a patent, which extends Pfizer's patent rights over Lipitor to June 2011, last week.

Being the holder of 180-day exclusive marketing rights for atorvastatin (the generic name of Lipitor), Ranbaxy is likely to be the biggest beneficiary of the decision. Pfizer, however, has the option to appeal against the decision.

When contacted, a Ranbaxy spokesperson declined to comment on the development. "We have chosen not to comment on this development at this point of time. The matter is also before the US court," he said.

"The decision comes as a big boost to help Ranbaxy secure the 180-day exclusivity. The US Patent and Trademark Office is unlikely to review its decision as it normally reviews all the issues related to the patent, including the previous court rulings. Even if Pfizer further pursues the case in the Supreme Court, the US Patent and Trademark Office decision will help Ranbaxy get a favourable ruling," said Gopakumar G Nair, a patent expert.

Meanwhile, Mohan Dewan, another patent expert, noted that the decision did not mean a final ruling on the patent in favour of Ranbaxy.

"This is a temporary victory for Ranbaxy. Pfizer can appeal the decision with the US patent office and its decision can also be challenged in the courts," he said.

In August last year, the US Court of Appeals for the Federal Circuit had invalidated Pfizer's US patent no 5,273,995 ('995) on atorvastatin (Lipitor) and had reversed a US district court judgement that went against the patent challenger Ranbaxy.

Following this, Pfizer approached the US patent office claiming to correct the "technical flaws" in the patent and to reissue a new patent. If the patent office had accepted Pfizer's views, the patent would have been valid until June 2011.

Ranbaxy has been fighting the Lipitor battle with Pfizer in about 17 countries since 2002.