Hopes for the introduction of a generic version of Pfizer's Lipitor (atorvastatin calcium) suffered a setback as the Supreme Court declined to intervene in Ranbaxy Laboratories Ltd's challenge of a lower-court decision that upheld Pfizer's patent for the blockbuster cholesterol-lowering drug. The US patent for Lipitor is not due to expire until March 2010, but Ranbaxy had sought to market a generic version prior to that date. The Supreme Court's action shuts the door on that effort.

Ranbaxy's litigation was not entirely fruitless, however. The Supreme Court ruling also let stand previous action by a lower court that effectively whittled down Lipitor's patent protection by 15 months. Pfizer is currently seeking a ruling from the US Patent and Trademark Office that would restore Lipitor's patent through June 2011.