Federal Circuit Decides Important Biotechnology Written Description Case

In Carnegie Mellon University v. Hoffman-La Roche, decided September 8, 2008, the Federal Circuit affirmed a district court’s holding on summary judgment that claims directed to a recombinant plasmid containing a DNA polymerase I gene, isolated from any bacterial source, under the control of the conditionally controllable foreign promoter were invalid for failure to comply with the written description requirement.

The decision is significant in a number of respects. For one thing, it is the first time the Federal Circuit has invalidated a claim directed to a DNA sequence (or any biological molecule for that matter) in a situation not involving the discovery of a novel DNA sequence. For example, in UC Regents v. Eli Lilly (1997), the first case in which the Federal Circuit applied the written description requirement to invalidate an originally filed, non-amended claim, the invalidated claims were directed towards novel genetic sequences encoding insulin. Likewise, in In re Wallach (2004) the court invalidated claims reciting newly discovered TBP-II genes for failure to comply with what I refer to as the Lilly written description requirement (in contrast with the traditional written description requirement, which is applicable only to amended claims or claims added after the initial filing date).

In Carnegie Mellon, on the other hand, the essence of the invention was the discovery of a means of regulating the expression of the gene encoding DNA polymerase I (polA) to avoid lethality problems associated with over expression of the gene. The polA gene had previously been isolated from three different species of bacteria, and conditionally controllable promoters were also known in the prior art. Carnegie Mellon argued that the holding in Lilly was limited to inventions involving novel DNA sequences, but the Federal Circuit explicitly rejected this argument.

The court also voiced its approval of the USPTO’s 2001 “Written Description Guidelines,” (which were recently superseded by updated guidelines, as discussed in a previous post) finding it to be “persuasive authority” providing guidance in interpreting the written description requirement.

Carnegie Mellon is arguably inconsistent with the Federal Circuit's 2005 decision in Capon v. Eshhar, in which the Federal Circuit reversed a Board of Patent Appeals and Interferences holding that a claim directed to a chimeric DNA sequence failed to satisfy the written description requirement. For example, in Capon the court found that the Board had erred in holding that the written description requirement was not met because the specification failed to recite the structure or formula or chemical name for the DNA sequence components of the claimed chimeric genes. In that case, the court held that it was sufficient that sequences that could function as the segments of the chimeric gene were known in the prior art, and that the applicant was not required to "reiterate" those sequences in the application. In contrast, in Carnegie Mellon the court found it significant that the patent specification only discloses a DNA polymerase gene from a single bacterial species, even though the corresponding gene from two other bacterial species were known at the time of invention.

More striking, the claims in Capon define the chimeric gene in terms of two genetic elements that are defined in much broader, generic terms than the DNA polymerase I gene at issue in Carnegie Mellon. In particular, the Capon claims recite a genus of chimeric genes comprising a first segment encoding some portion of an antibody capable of binding an antigen, and the second segment encoding at least some portion of a protein that (1) is expressed on the surface of cells of the immune system and (2) triggers activation and/or proliferation of the cells. The Carnegie Mellon court distinguished the two cases by noting that in Capon the prior art contained “extensive knowledge of the nucleotide structure of the various and immune-related segments of DNA, including over 785 mouse antibody DNA light chains and 1327 mouse antibody DNA heavy chains,” while only three bacterial DNA polymerase I genes “out of thousands” had been cloned at the time of Carnegie Mellon's invention. However, the court fails to acknowledge the extreme structural variability in antibodies (Capon) compared to DNA polymerases (Carnegie Mellon). Furthermore, the court entirely ignores the extremely broad functional language defining the second element of the Capon chimeric gene, i.e., any segment encoding a protein expressed on the cell surface of cells of the immune system (there are a host of such cells) and capable of triggering activation or proliferation of the cells.

Carnegie Mellon is a significant affirmation of a continuing distinct role for the written description requirement in policing the scope of patent claims, typically in the area of biotechnology. However, it provides little guidance in applying the doctrine, particularly when one considers the seeming inconsistency between the outcomes in this case and Capon. My position is that the court is misguided in its application of the written description requirement in this manner, and the more appropriate tool for policing claim scope is the enablement requirement, but particularly over the last few years Lilly written description is increasingly taking on a life of its own.