Kingsdown Medical Consultants, Ltd. v. Hollister Inc.
Court of Appeals for the Federal Circuit
863 F.2d 867 (1988)
During Kingsdown's (plaintiff) years-long patent prosecution, its attorney mistakenly resubmitted an originally rejected claim 50 instead of the amended version examiners had indicated would be allowable, an error that slipped through and issued as claim 43; this happened after Kingsdown learned of a Hollister (defendant) device it believed infringed and filed a continuation application to accelerate prosecution. Hollister argued the entire patent was invalid for inequitable conduct, characterizing the error as gross negligence coinciding suspiciously with the emerging infringement dispute, and the district court agreed and held the patent invalid.
Whether a patent applicant's carelessness, even gross negligence, during patent prosecution, without any showing of intent to deceive, is sufficient to render the patent invalid for inequitable conduct.