(Adds background on litigation)
July 25 (Reuters) - A U.S. appeals court on Wednesday denied a request by Acorda Therapeutics Inc for a temporary court order blocking generic drug companies from launching lower-cost versions of its multiple sclerosis drug Ampyra.
The U.S. Court of Appeals for the Federal Circuit said it would not block Teva Pharmaceutical Industries Ltd and other companies from selling generic versions of Ampyra while it reviews a lower court decision that ruled invalid Acorda patents covering the drug.
Acorda's stock dropped 12 percent to about $25 early on Wednesday after the ruling was issued. It was last down 9.8 percent at $25.90 in early afternoon trading.
An Acorda spokeswoman did not immediately respond to a request for comment.
A federal judge in Delaware ruled in March 2017 that four Acorda patents relating to Ampyra were invalid because they described obvious ideas, opening the door for generic competition.
Units of Teva, Mylan NV and Hikma Pharmaceuticals Plc have said in court filings that they could launch a generic version of Ampyra after July 30, when a fifth Acorda patent covering Ampyra will expire.
In May, Acorda asked the Federal Circuit to issue an injunction blocking generic sales while the court reviews the lower court decision, arguing it "will suffer devastating and irreparable harm from a generic launch during the pendency of its appeal."
The appeals rejected that argument, saying: "Acorda has not established that an injunction pending appeal is warranted."
The court did not say when it would rule on the validity of Acorda's Ampyra patents. (Reporting by Jan Wolfe; editing by Dan Grebler and G Crosse)