What is the legal concept of estoppel in patent interference proceedings?

In patent interference proceedings, estoppel is a legal concept that prevents a party from raising an issue if they have already lost on that issue during the interference. This principle is outlined in MPEP 2308.03(a), which states:

“A party is barred (estopped) from raising an issue if the party lost on the issue during the interference.”

This means that if a party has unsuccessfully argued a particular point during an interference proceeding, they cannot later attempt to re-litigate or raise that same issue in subsequent proceedings or patent applications.

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Topics: MPEP 2300 - Interference And Derivation Proceedings, MPEP 2308.03(A) - Losing Party, Patent Law, Patent Procedure
Tags: Estoppel, Legal Concepts, Patent Interference, USPTO procedures