Pharmacyclics Shares Fall As Kyle Bass Files Petition To Cancel Patent

Pharmacyclics, Inc. PCYC fell victim Monday to the latest patent challenge by hedge fund manager and short seller Kyle Bass.

AbbVie Inc ABBV agreed last month to acquire Pharmacyclics for $21 billion.

Dallas-based Hayman Capital Management L.P., managed by Bass, challenged one of Pharmacyclics' patents on Imbruvica, as treatment for mantle cell lymphoma.

Related Link: Here's Why AbbVie's Pharmacyclics Deal Will Boost Revenue 5%

AbbVie expects Imbruvica sales to reach $1 billion in 2015, eventually hitting peak annual sales of $7 billion.

In January, Bass told an investment conference in Norway of plans to challenge pharmaceutical patents via a so-called Inter Partes Review process created by Congress in 2012.

The process entails hearings before a U.S. Patent Office panel as a cheaper and faster alternative to court trials, and was formed to help fight patent trolls.

The Imbruvica challenge is the latest for Bass, who has mounted similar objections so far to patents held by Jazz Pharmaceuticals plc JAZZ, Acorda Therapeutics Inc. ACOR and Shire PLC SHPG.