What: Shares of Acorda Therapeutics (NASDAQ:ACOR), a biopharmaceutical company specializing in neurological disorders, saw its shares rise by as much as 21% today on exceptional volume, before settling in on a gain of 12% at the time of this writing. Acorda's rally was triggered by the news that the hedge fund manager Kyle Bass's attempts to invalidate two key patents, 8,663,685 and 8,007,826, protecting Acorda's flagship multiple sclerosis drug Ampyra were shot down by the U.S. Patent and Trademark Office, or USPTO. Specifically, Acorda announced that the USPTO declined a so-called "inter partes review" of these two patents, previously filed by Bass's Coalition for Affordable Drugs.

So what: Acorda's shares have been under heavy pressure ever since Bass's group initiated the review last February. Prior to today's jump, for example, the drugmaker's shares were down close to 30% for the year, despite the company posting double-digit revenue growth throughout the first half of 2015. 

ACOR Chart

Now what: Ampyra's core patents were probably never in any real trouble, evinced by how quickly and resoundingly the USPTO acted in this case. Instead, Bass is drawing the ire of pharmas far and wide, with Celgene reportedly seeking to sanction the hedge fund manager for abusive practices. Most importantly, though, this news may be a harbinger of things to come for Bass's other outstanding patent challenges. Stay tuned.