Does res judicata apply in patent reexamination proceedings?
Res judicata, or claim preclusion, generally does not apply in patent reexamination proceedings. The MPEP § 2259 states:
“A rejection on the grounds of res judicata will not be appropriate in reexamination.”
This is because one of the essential elements of res judicata is the involvement of the same parties, and the USPTO is not a party to prior court litigation. The MPEP further clarifies:
“The doctrine of res judicata based on a court holding in an infringement proceeding is not applicable in reexamination proceedings, because the Office was not a party to the litigation.”
This means that even if a court has made a decision on a patent’s validity, the USPTO can still reexamine the patent without being bound by the court’s decision.
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