Acorda Therapeutics Inc. said a U.S. appeals court upheld a District Court's decision to invalidate four U.S. patents related to its multiple sclerosis drug Ampyra.

The company's stock was down 24.50% to $20.80 as of market close Sept. 10.

Ardsley, N.Y.-based Acorda said it was reviewing the decision and will consider future options, including the possibility of a further appeal.

The biopharmaceutical company said the U.S. Court of Appeals for the Federal Circuit, by a 2-1 vote, upheld the U.S. District Court for the District of Delaware's decision to invalidate four patents related to extended-release tablets of Ampyra.

According to a Sept. 10 news release, the only other patent previously upheld by the District Court expired July 30.

"Following the court's original decision in 2017, we prepared a contingency plan that we could face generic competition, implementing a comprehensive corporate restructuring and bolstering our balance sheet," said Acorda President and CEO Ron Cohen.

Cohen added that the company was well-capitalized and focused on the potential launch of its Parkinson's disease drug Inbrija.

Acorda is a biopharmaceutical company that develops and commercializes therapies for neurological disorders in the U.S.