What is the “Inoperative Subject Matter” rule in patent enablement?

What is the “Inoperative Subject Matter” rule in patent enablement?

The “Inoperative Subject Matter” rule is an important consideration in patent enablement. According to MPEP 2164.08(b):

“A claim which reads on significant numbers of inoperative embodiments would render the claims nonenabled when the specification does not clearly identify the operative embodiments and undue experimentation is involved in determining those that are operative.”

This rule means that if a claim encompasses a large number of inoperative variations or embodiments, it may be rejected for lack of enablement. The key factors are whether the specification clearly identifies which embodiments are operative and whether it would require undue experimentation to determine the operative ones. To avoid this issue, applicants should ensure their claims are not overly broad and that the specification provides clear guidance on which embodiments are functional and how to identify or create them without undue experimentation.

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Topics: MPEP 2100 - Patentability, MPEP 2164.08 - Enablement Commensurate In Scope With The Claims, Patent Law, Patent Procedure
Tags: Enablement, Inoperative Subject Matter, MPEP 2164.08(B), patent claims