Acorda Therapeutics' Stock Plummets Toward Biggest-ever Loss Amid Disappointing Patent Ruling

Acorda Therapeutics Inc. said Friday that four of its patents pertaining to its Parkinson's disease treatment, Ampyra, were invalidated by the U.S. District Court for Delaware. The court also upheld one patent pertaining to Ampyra extended release tablets. The stock had plunged 24% prior to a trading halt, which went into effect at 12:07 p.m. ET, and was set to be lifted at 1 p.m. That puts the stock on course to suffer the biggest one-day percentage decline since it went public in February 2006. "We are disappointed by the Court's decision and are preparing our appeal," Chief Executive Ron Cohen. "Medical innovation depends on the recognition of valid intellectual property claims." The stock had gained 8% year to date prior to the halt, while the S&P 500 has gained 5.8%.