WASHINGTON - Teva Pharmaceutical Industries Ltd. on Thursday told the U.S. Supreme Court that it is willing to post up to a $500 million bond in return for a decision suspending a lower-court ruling that would allow generic competitors to go on the market as soon as next month.

Teva, whose Americas headquarters is in North Wales, Montgomery County, already had asked the court for a stay of the July 2013 ruling by the U.S. Court of Appeals for the Federal Circuit that invalidated some of its patents for the top-selling multiple sclerosis drug Copaxone.

The case was won by two teams developing generic versions of the drug: one comprising Novartis AG's Sandoz Inc. and Momenta Pharmaceuticals Inc., and the other comprising Mylan Inc. and Natco Pharma Ltd.

The generic drugmakers suggested in their response to the stay application that Teva pay a bond, saying it would protect them should they eventually win the case and require compensation for the period in which they were prevented from entering the market.

The Supreme Court has yet to respond to Teva's stay application, submitted on April 7.

On March 31, the high court agreed to hear Teva's appeal of the appeals court ruling, but Teva subsequently filed additional court papers, asking the high court to prevent the lower-court ruling from going into effect while the case is decided.

The appeals court had declared several patents invalid, meaning patent protections were set to expire in May 2014 instead of September 2015. Teva made its last-ditch request for a stay because by the time the court has decided on the regular appeal, the generic drugs could already be on the market.

The Supreme Court will not be hearing oral arguments in the Teva case until its 2014 term begins in October. A ruling could come as late as June 2015.

Separately on Thursday, Teva signed a deal that allows it to launch a generic version of Pfizer Inc.'s blockbuster painkiller Celebrex in December.

A U.S. court in March invalidated a patent extending Pfizer's marketing exclusivity for Celebrex to Dec. 2, 2015. Celebrex's basic chemical patent is set to expire this May.

Pfizer said on Thursday it would continue to defend the patent extending its marketing exclusivity.

The deal "helps them to get through 2014 with a lot less competition," Morningstar analyst Damien Conover said. "As soon as other generics get in, [Pfizer's] sales will erode even quicker."

The U.S. Food and Drug Administration usually grants 180 days of marketing exclusivity to drugmakers who are first to file for generic approvals.