Drugmaker Pfizer celebrated on Tuesday as a new patent extended intellectual property rights for anti-inflammatory painkiller Celebrex - meaning it will rake in billions from health providers.
Shares of New York-based Pfizer jumped nearly 2 per cent after news that the drug's US protection will continue for another 18 months.
Pfizer also filed a lawsuit against five other drugmakers to try to prevent them from selling generic versions of Celebrex before December 2015.
Pfizer said the US Patent and Trademark Office has granted a "reissue patent" to replace an older patent a federal appeals court had ruled invalid in 2008.
The reissue patent corrects what Pfizer said were technical deficiencies in the original patent.
If Pfizer's lawsuit is not resolved before May 2014, Pfizer noted that it would have to seek a preliminary injunction blocking all sales of generic Celebrex, to prevent "irreparable and irreversible harm" to its interests.