A federal appeals court on Friday upheld a Delaware judge’s decision that invalidated four patents for Teva Pharmaceutical’s Copaxone, clearing the way for competitors to bring generic versions of the company’s multiple sclerosis drug to market.

The decision, from the U.S. Court of Appeals for the Federal Circuit, affects a contingent of drugmakers in New Jersey and Pennsylvania, which had applied to develop generic alternatives to the thrice-weekly, 40-milligram treatment for relapsing-remitting MS. The firms were represented on appeal by Deanne Maynard of Morrison & Foerster in Washington and Shannon Bloodworth of Perkins Coie, who practices out of Washington and Madison, Wisconsin.