Docket No. 2012-1120
DYK, PLAGER, REYNA
April 16, 2013
Brief Summary: Claim term “anti-CD20 antibody” determined to refer to those antibodies “that bind to the same epitope of the CD20 antigen with similar affinity and specificity” as Rituxan® due to prosecution history disclaimer.
Summary: Biogen sought review of DC construction of the narrowing of the term “anti-CD20 antibody” in US 7,682,612 because of a disclaimer. Under the DC construction, Biogen stipulated it could not prove infringement. The claims were not limited to any particular type of antibody (e.g., dependent claims to chimeric, rituximab (Biogen’s commercial product Rituxan®), humanized and human antibodies). GSK’s anti-CD20 antibody is Arzerra® and binds to a different CD20 epitope than Rituxan®. The DC determined “anti-CD20” referred to “rituximab and antibodies that bind to the same epitope of the CD20 antigen with similar affinity and specificity as rituximab” but Biogen argued for the broader construction “an antibody that binds to a cell surface CD20 antigen” (e.g., the “plain and ordinary meaning”). The FC panel considered whether any of the prosecution history could “overcome the ‘heavy presumption; that the term carries its full ordinary and customary meaning”. During prosecution of the ‘612 patent, the claims were rejected for enablement as to “any and all anti-CD20 antibodies” but Biogen overcame these rejections by arguing that “one of skill in the art could readily identify an antibody that binds to CD20 with similar affinity and specificity as does Rituxan® using techniques that are well known in the art….” The FC panel noted that this response was made “rather than challenging the examiner’s understanding of the crucial terms” (TorPharm, FC 2003 (if an applicant chooses,she can challenge an examiner’s characterization in order to avoid any chance for disclaimer)), thus “limiting their invention to what the examiner believed they enabled: antibodies that have a similar specificity and affinity for the specific epitope to which Rituxan® binds.” Biogen’s claim differentiation and improper importation arguments were rejected because the limited construction “is not necessarily inconsistent with” the chimeric and other antibodies covered by the dependent claims and other embodiments. Biogen also attempted to incorporate the broader definition from an earlier patent but the panel maintained that the term would still need to be read in the context of the ‘612 patent. Therefore, the DC decision was affirmed. Judge Plager dissent argued that the disclaimer was not clear and unmistakable because the applicant used the term “similar” which does not mean “the same”.