Statements made to overcome enablement rejection may limit claims in spite of plain meaning and claim differentiation.

Biogen Idec, Inc. v. Glaxosmithkline LLC, No. 12-1120 (Fed. Cir. Apr. 16, 2013).

The district court adopted a claim construction that forced the patentee to concede non-infringement of the asserted claims based on the doctrine of prosecution history disclaimer. The patentee appealed on the grounds that the claim construction was improper as the disclaimer was not clear and the construction departed from the plain and ordinary meaning, excluded the preferred embodiment, and would dissolve the distinction between certain dependent claims and the independent claim.

The Federal Circuit affirmed the claim construction ruling. During prosecution, the examiner rejected the independent claims as not enabling the full scope of what was claimed, but only a subset. In response, the patentee argued that the identified subset of the claim was enabled based the demonstrated binding of one antibody and the assertion that skilled artisans could arrive at other antibodies that provide “binding with similar affinity and specificity.” The examiner accepted the argument and withdrew the rejection. This exchange constituted prosecution history disclaimer because the patentee did not dispute the examiner’s characterization of lack of enablement for the full scope of the claim and the demonstration of enablement was made only for the identified subset of the claim and other antibodies that bind in the same way.   

During the district court proceeding, the alleged infringer's claim interpretation was adopted and infringement was not found because of the different binding mechanism for the alleged infringer’s antibodies. The patentee unsuccessfully argued that such a decision was incorrect based on the plain language of the claim as well as by the doctrine of claim differentiation. The Federal Circuit rejected the patentee’s arguments holding that prosecution history disclaimer overcomes the presumption against claim differentiation, excluding preferred embodiments, and the strict use of the plain and ordinary meaning of claim terms. As the pantentee disclaimed antibodies that have different binding mechanisms, the decision of non-infringement was affirmed. 

A copy of the opinion can be found here.