A “Substantially Equivalent” Disclosure May Satisfy the Written Description Requirement

NALPROPION PHARMACEUTICALS, INC. v. ACTAVIS LABORATORIES FL, INC.

Before Prost, Lourie and Wallach. Appeal from the U.S. District Court for the District of Delaware. 

Summary: A “substantially equivalent” disclosure may satisfy the written description requirement where the “equivalent disclosure” relates only to resultant parameters rather than operative claim steps.

Nalprion filed a suit against Actavis for patent infringement related to an application to market a generic version of Contrave®.  In response, Actavis challenged one patent as invalid for lack of adequate written description.  The challenged patent was directed to a method of treating overweight or obesity, and was drawn to use of a specific dosage of active agents that achieve a specific dissolution profile. Actavis argued that the claimed dissolution profile required the use of one dissolution method (“USP 2”), while the data in the specification was obtained using a different method (“USP 1”).  Actavis further challenged two other patents as invalid as obvious.  The district court held each claim not invalid and infringed. Actavis appealed.          

The Federal Circuit affirmed the district court’s findings on written description, holding that the district court did not clearly err in finding that the inventors had possession of the invention.  The Federal Circuit explained that the patent recited a method of treating overweight or obesity by carrying out the specific, positive steps, and the claimed dissolution profile related only to the measurement of resultant parameters (the dissolution data resulting from the formulation), not to the operative steps (the administration of the formulation). Thus, irrespective of the method of measurement (USP 1 or 2) used, the specification shows that the inventors possessed the invention for treating overweight or obesity.  The Federal Circuit also did not find error in the district court’s finding of “substantial equivalence” between the USP 1 and USP 2 methods.   The Federal Circuit recognized that, as a general matter, written description cannot be satisfied by equivalent disclosures.  But, here, where the equivalence relates only to resultant dissolution parameters, rather than operative claim steps, and is supported by the district court’s fact finding, the district court did not err in finding the patent was not invalid for lack of written description support.  The Federal Circuit then went on to reverse the district court’s holding of obviousness of the two other patents. 

Chief Judge Prost dissented in part, disagreeing that the dissolution clause did not relate to operative claim steps and stating that the majority’s holding that a “substantially equivalent” disclosure may satisfy the written description requirement is inconsistent with the Federal Circuit’s precedent.

Editor: Paul Stewart