Federal Circuit Holds that Prosecution Disclaimer Does Not Apply to an Abandoned Argument About Patent Scope

In Malvern Panalytical Inc. v. TA Instruments-Waters LLC, the Federal Circuit held that the doctrine of prosecution disclaimer does not apply to an abandoned argument about the scope of a patent during prosecution of an unrelated but relevant patent, reversing the District Court’s holding. During prosecution of an unrelated patent, the Examiner rejected the claims as anticipated by one of the patents in suit, the ‘175 patent. The Applicant’s response to the Examiner limited the scope of the ‘175 patent, which contradicted their proposed claim construction in the present case. The Applicant later overcame the rejection by arguing that the ‘175 did not qualify as prior art and thus abandoned their previous argument that limited the scope of the ‘175 patent. The Federal Circuit relied on the fact that the Examiner rejected the Applicant’s argument about the scope of the patent several times and that the Applicant “acquiesced to the examiner’s view” by abandoning the argument. Therefore, “the prosecution history lack[ed] the clarity necessary to establish prosecution disclaimer,” so the Applicant’s argument during the prosecution history of the unrelated patent could not be used to limit the claim construction of the claims in the present case.


Written by Niki Camateros-Mann