April 7, 2022by Matthew Barnet

U.S. patent claims typically use the terms “comprising” and “consisting of” when reciting components of a composition. “Comprising” indicates that the composition must include the recited components, but also can include unrecited components, while “consisting of” indicates that the composition excludes unrecited components.

The term “comprising” advantageously provides the applicant with broader scope of protection than “consisting of.” However, such breadth sometimes opens claims to additional prior art. In such cases, “consisting of” can be helpful to distinguish the claims from the prior art.

When claims use both “comprising” and “consisting of,” the scope of the claims must be analyzed carefully. This issue is illustrated in the recent case of Ex parte Rankin (Appeal No. 2021-001726).

Independent claim 40 recited (in part) a composition comprising:

(i) a gel base consisting of:

a wax or oil and;

a salt; and

(ii) titanium dioxide, zinc oxide, barium sulfate, or a combination thereof dispersed in the gel base.

The examiner rejected claim 40 as anticipated by two different references disclosing gels containing titanium dioxide. The gels also included polymeric gelling agents. In each case, the examiner took the position that the gelling agent was within the scope of the claim based on the open “comprising” term in the preamble. For example, in one anticipation rejection, the examiner stated that claim 40 “is interpreted to mean that the gel base consists of a wax or oil, and a salt, but it does not exclude addition of other components, such as the block polymers taught by [the cited reference] to make the final…product.”

In contrast, the applicant argued that the closed “consisting of” term excluded the polymeric gelling agents of the prior art. For example, the applicant alleged that the gels of the cited reference “differ structurally from the gel of claims 40-55 due to the latter being composed exclusively of a wax or oil and salt and therefore excluding the polymers…as constituent structural components.”

The PTAB agreed with the applicant. The PTAB acknowledged that “the ‘comprising’ language in the claim allows the mixture of the gel base and titanium dioxide, zinc oxide, barium sulfate or combination to include additional components dispersed in the gel base.” However, due to the “consisting of” language, “the gel base may contain only the recited wax or oil and salt…[W]e do not agree [with the examiner] that the claim language allows for the addition of ingredients to the gel base.” Accordingly, the PTAB reversed the anticipation rejections.

Takeaway: Whenever a claim uses both “comprising” and “consisting of,” the scope of the claim must be analyzed carefully. The closed, “consisting of” term might be intended to exclude a component disclosed in the prior art, but the examiner might take the position that the component is within the claim scope due to the “comprising” term. In such cases, it is important to clearly identify how the components of the prior art correspond to the claim. In Rankin, the applicant successfully argued that the polymeric gelling agent of the prior art was a component of the gel base (thus excluded by the “consisting of” term) rather than a component dispersed in the gel base (which would have been included by the “comprising” term).

Judges: Adams, Grimes, Jenks


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


September 24, 2020by Beau Burton

The term “comprising,” when used in the preamble of a claim, permits the inclusion of other elements or materials in addition to those specified in the claim. However, “‘comprising’ is not a weasel word with which to abrogate claim limitations.” Dippin’ Dots, Inc. v. Mosey, 476 F.3d 1337, 1343 (Fed.Cir.2007).

Ex parte Martino involved a claim that required “[a] hand held olfactory tester comprisinga single odorant chamber.” Decision on Appeal, Appeal No. 2020-001003, at 2 (P.T.A.B. Sept. 11, 2020) (non-precedential).

In rejecting the claim, the Examiner only presented prior art having a tester with a plurality of chambers. Yet, the Examiner argued that the claim was obvious because “the plurality of containers shown [in the prior art] also include a single container.” Id. at 6. According to the Examiner, the claims needed to recite that the tester consists of only a single chamber because the term “comprising” allowed for additional, unrecited elements.

The Applicant disagreed, because the claim explicitly required a single chamber. The Board sided with the Applicant.

The Board noted that “[t]he presumption raised by the term ‘comprising’ does not reach into each of the [elements] to render every word and phrase therein open-ended,” and must be read in view of the specification. Id. at 4. The Board then applied a two-step analysis. First, the Board found that the ordinary and customary meaning of the term “single” is “one and only one.” Next, the Board confirmed that the specification was consistent with this meaning. Here, the Board highlighted, among other things, that the specification differentiated prior art testers having a number of odorant chambers, described a housing  with “an odorant chamber,” and depicted a device with only one chamber. Consequently, the Board found that the term “comprising” in the preamble did not negate the meaning of “single” as understood by one in the art.

Without any prior art disclosing or otherwise suggesting a tester comprising a single chamber, the Board reversed the Examiner’s obviousness rejection.

Takeaway: The scenario in Martino is quite common because of the presumption to construe the term “comprising” to be nonexclusive and the tendency for some examiners to play wordsmith. Martino also shows that even when there is no ambiguity in the claim language, the Board may still consult the specification for consistency with the ordinary and customary meaning of a term like “single.” So, what other options are available if you want to claim a limited number (e.g., one) of an element but the specification permits a plurality? One option is to add a wherein clause that states, “wherein the [device, article, composition, etc.] comprises no more than one element.”

Judges: A. Fetting, U. Jenks, A. Shah