The U.S. Court of Appeals for the Federal Circuit recently issued an en banc decision upholding an earlier ruling that patent applications must contain a specific “written description” of the claimed invention in addition to enabling language explaining how to make and use the invention.

The court’s decision Monday in Ariad Pharmaceuticals Inc. v. Eli Lilly and Co., which includes two separate dissenting-in-part and concurring-in-part opinions and a concurring opinion, upheld the court’s April 3, 2009, panel ruling. Circuit Judge Pauline Newman joined the majority opinion but submitted additional views.