The Court of Appeals for the Federal Circuit (CAFC) recently issued on en banc decision in Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., essentially leaving the written description requirement intact.  In that case, Ariad filed a patent application relating to NF-kB and its involvement in activating gene expression underlying the body’s immune response to infection.  Once issued, Ariad and others sued Lilly for infringement, and the district court found that Lilly did indeed infringe some of the claims.  The district court also determined that the patent was not invalid for anticipation, lack of enablement or lack of written description.  On appeal, the CAFC reversed this decision, holding the Ariad patent invalid for lack of written description.  Ariad then petitioned for en banc review, which the CAFC granted.  Relying on the language in the statute, Supreme Court precedent and policy considerations, the en banc court ruled that the written description requirement was indeed separate and independent from the enablement requirement and affirmed that the Ariad patent is invalid for lack of written description. 

In his public blog, Director Kappos provided comments in response to this decision.  He suggests that some of the principles noted by the majority when analyzing whether or not the written description is met were also discussed in the USPTO’s 2001 Written Description Guidelines and exemplified in the 2008 Revised Written Description Training Materials.  He states that one of these principles involves considering “whether the specification discloses a representative number of species, sufficient structure, and/or a sufficient correlation of function to structure.”  Director Kappos suggests that although the written description requirement may not be used in a vast majority of cases, it is nevertheless an important tool for Examiner’s to use when a patentee is attempting to claim more than what he/she has invented.  He specifically mentions the usefulness of written description as it is applied to claims reciting functional language, for example, when a genus claim uses functional language to define what species are encompassed by the claim.

 The Ariad case demonstrates a common problem in the chemical and biotechnology arts.  Typically, an invention is discovered at an early stage, at which point a patent application is filed.  If the invention shows promise, further research is performed, and additional information that may not have been disclosed in the initial patent application is now trying to be claimed.  As noted by Director Kappos, this can occur where a compound is disclosed but a claim directed to a broad genus encompassing the compound is pursued.  Such a claim may be rejected for lack of written description.  To the extent possible, it is generally good practice to include any relevant experimental information showing multiple species in the context of the invention at the time of initial filing of a patent application.