Can a Markush claim be rejected as indefinite?
Yes, a Markush claim can be rejected as indefinite under 35 U.S.C. 112(b) if one skilled in the art cannot determine the metes and bounds of the Markush claim due to an inability to envision all of the members of the Markush grouping. This typically occurs when:
- The list of alternatives is not a closed grouping
- The Markush group is so expansive that persons skilled in the art cannot determine the metes and bounds of the claimed invention
The MPEP states: See MPEP § 2173.05(h) for discussions of when a Markush grouping may be indefinite under 35 U.S.C. 112(b) (e.g., if the list of alternatives is not a closed grouping, or if a Markush group is so expansive that persons skilled in the art cannot determine the metes and bounds of the claimed invention).
It’s important to note that an indefiniteness rejection is separate from an improper Markush grouping rejection and addresses different issues in the claim.
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