February 3, 2023by Jacob Doughty

Ex parte Fox is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing the interpretation of a Markush group in a claim rejected for anticipation and obviousness.  

The claim at issue was directed to “[a] cleaning solution comprising one or more solvents selected from the group consisting of acetoacetates, alcohols, glycol ethers, glycol esters, terpenes, and water…” The claim also required other components and properties. 

The examiner identified a cleaning solution in the prior art which included some of the solvents listed in the claim. However, the prior art cleaning solution required a further solvent, “at least one oxyisobutyric acid ester.” The examiner asserted that, although at least one of the listed solvents must be present, the “comprising” language in the claim permitted the presence of additional solvents in the cleaning solution.  

The examiner supported his position by citing MPEP 2111.03.II, which, in turn, cites In re Crish, 393 F.3d 1253 (Fed. Cir. 2004). The examiner relied on the following description of the Crish case from the MPEP:  

In determining the scope of applicant’s claims directed to “a purified oligonucleotide comprising at least a portion of the nucleotide sequence of SEQ ID NO:1 wherein said portion consists of the nucleotide sequence from [521] to 2473 of SEQ ID NO:1…” the court stated that the use of “consists” in the body of the claims did not limit the open-ended “comprising” language in the claims… 

The PTAB stated that a case cited in the same paragraph of the MPEP relied on by the examiner, Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp., 831 F.3d 1350, (Fed. Cir. 2016), included a fact pattern much closer to the claim on appeal. The PTAB stated that Crish was distinguishable from the claims on appeal, because Crish did not involve a Markush group of distinct alternatives from which to select. 

Relying on the Multilayer case, the PTAB noted that the use of the transitional phrase “consisting of” to set off a patent claim element creates a very strong presumption that that claim element is closed and therefore excludes any elements, steps, or ingredients not specified in the claim. Thus, if a patent claim recites “a member selected from the group consisting of A, B, and C,” the member is presumed to be closed to alternative ingredients D, E, and F. In the claim on appeal, the “member” was the “solvent,” so the claim was closed to solvents other than those specifically recited in the Markush group – even though the claimed cleaning solution was open to containing other non-solvent elements. 

When the claim on appeal was properly construed, the prior art was not sufficient to anticipate or render obvious the claim, because the prior art required the presence of “at least one oxyisobutyric acid ester” solvent, i.e, a solvent that was not recited in the Markush group of the claim.  

Takeaway: Markush groups are frequently used to define components of composition. It is important to be intentional when drafting Markush group to control what is within and outside the scope of the claim. In thinking about a claim drafted in typical Markush format, “an X selected from the group consisting of A, B, and C,” attention is often focused on A, B, and C, which define what must be present. However, care must be taken in defining X which indicates what will be excluded from the claim. A broad X may define over the prior art but may also make design-around compositions easy to identify.  

Judges: Cashion, McGee, Inglese


July 13, 2021by Beau Burton

Ex parte Kiely is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether a Markush group stating “selection from the group comprising” was indefinite.

In Ex parte Kiely the Appellant argued that the phrase “selection from the group comprising” was not improper because the Examiner allowed claims in another application with language and alleged that such phrasing was found proper in Multilayer Stretch Cling Film Holdings, Incorporated v. Berry Plastics Corporation, 831 F.3d 1350 (Fed. Cir. 2016). The PTAB disagreed.

First, the PTAB relied on Abbott Labs. v. Baxter Pharm. Products, Inc. for the proposition that “a proper Markush group is limited by the closed language term ‘consisting of.’” 334 F.3d 1274, 1281 (Fed. Cir. 2003). The PTAB also cited MPEP § 2173.05(h), which states “[i]f a Markush grouping requires a material selected from an open list of alternatives (e.g., selected from the group ‘comprising’ or ‘consisting essentially of’ the recited alternatives), the claim should generally be rejected under 35 U.S.C. 112(b) as indefinite because it is unclear what other alternatives are intended to be encompassed by the claim.”

With respect to Appellant’s reliance on Multilayer Stretch Cling, the PTAB noted that this case did not sanction the phrase “selected from the group comprising.” The claims at issue in Multilayer Stretch Cling did not even use this language. To the contrary, the court in Multilayer Stretch Cling stated:

[I]f a patent claim recites ‘a member selected from the group consisting of A, B, and C,’ the ‘member’ is presumed to be closed to alternative ingredients D, E, and F. By contrast, the alternative transitional term ‘comprising’ creates a presumption that the recited elements are only a part of the device, that the claim does not exclude additional, unrecited elements.

Finally, the PTAB rejected the Appellant’s argument that allowed claims in another application could cure the indefiniteness rejection because “compliance for each case with the statutory requirements is done on a case-by-case basis.” See In re Giolito, 530 F.2d 397, 400 (CCPA 1976)(“We reject appellants’ argument that the instant claims are allowable because similar claims have been allowed in a patent. It is immaterial whether similar claims have been allowed to others.”); see also In re Wertheim, 541 F.2d 257, 264 (CCPA 1976) (holding that “[i]t is immaterial in ex parte prosecution whether the same or similar claims have been allowed to others”).

Accordingly, the PTAB affirmed the Examiner’s indefiniteness rejection.

Takeaway: A Markush group is common when claiming alternative members for a particular purpose. The proper language for a Markush group is “selected from the group consisting of.” The PTAB in Ex parte Kiely was not open to an alternative format that bucked this convention. Thus, when claiming a Markush group it is best to use the standard phrasing. It is also important to remember that a Markush group carries a presumption that it is closed to unrecited alternatives and a presumption, albeit weaker, that it is closed to mixtures/blends of the recited alternatives. This latter presumption was overcome in Multilayer Stretch Cling, because the specification supported blends. Therefore, a Markush group should not be used when there is a clear intent for the claim to remain open to unrecited elements/members.

Judges: T. Owens, M. Colaianni, D. Praiss