## Facts

- Kingsdown Medical Consultants, Ltd. and E.R. Squibb & Sons, Inc. owned U.S. Patent No. 4,460,363 covering a two-piece ostomy appliance with cooperating coupling rings forming a fluid-tight seal.
- Kingsdown sued Hollister Incorporated for infringing multiple claims of the ’363 patent.
- The patent prosecution spanned over six years and involved extensive amendments, renumbering of 118 claims, a continuation application, and numerous cited references.
- In the parent application, a claim later identified as “claim 50” was rejected as indefinite under 35 U.S.C. § 112.
- In a continuation application, claim 50 was mistakenly reintroduced and later issued as claim 9 of the ’363 patent.
- The continuation filing included remarks characterizing the reintroduced claim as corresponding to an amended, allowed claim in the parent application, despite claim 50 not having been allowed.
- Kingsdown pursued the claim after learning of Hollister’s product, intending to obtain coverage that would block Hollister’s marketing.
- The district court held the entire patent unenforceable for inequitable conduct, inferring intent to deceive from the mischaracterization and Kingsdown’s failure to withdraw the application after the mistake was raised, and it did not reach infringement or validity.

## Issues

1. Whether the district court clearly erred in finding, by clear and convincing evidence, that Kingsdown intended to deceive the PTO in connection with the inclusion and prosecution of claim 9.
2. Whether negligence or “gross negligence” in prosecution conduct can support an inference of deceptive intent sufficient for inequitable conduct.
3. Whether pursuing claims to cover a competitor’s product, or failing to withdraw an application after an asserted error is identified, supports a finding of intent to deceive.

## Decision

- The Federal Circuit reversed the judgment of unenforceability for inequitable conduct and remanded for further proceedings.
- The court held that the district court’s finding of intent to deceive the PTO was clearly erroneous and that the inequitable-conduct determination was an abuse of discretion.
- The court treated the events as confusion and error in a complex prosecution record, not clear and convincing proof of deliberate deception.
- The reversal required vacatur of a related order finding the case exceptional and awarding attorney’s fees that had been predicated on the inequitable-conduct judgment.

## Legal Principles

- Inequitable conduct requires proof of both materiality and intent to deceive the PTO; intent must be shown by clear and convincing evidence and cannot be presumed from materiality alone.
- Negligence, even characterized as “gross negligence,” does not by itself justify an inference of intent to deceive.
- Failure to withdraw a patent application after an issue is raised is not, standing alone, sufficient evidence of intent to deceive.
- Amending or prosecuting claims with awareness of a competitor’s product is not improper per se; the focus remains on whether conduct before the PTO was knowingly false and aimed at deception.
- Courts should apply the intent requirement rigorously to avoid converting inequitable conduct into a routine allegation based on mistakes and aggressive but lawful prosecution strategy.

## Conclusion

The Federal Circuit reinstated enforceability of the patent by rejecting an inequitable-conduct finding that rested on mistake-based prosecution conduct and an improperly inferred intent to deceive, reaffirming that inequitable conduct demands clear and convincing proof of deceptive intent, not mere carelessness or aggressive claiming.


Kingsdown Med. Consultants, Ltd. v. Hollister Inc., 863 F.2d 867 (Fed. Cir. 1988) (en banc)