On August 10, 2007, the United States Patent and Trademark Office (USPTO) published a Notice of Proposed Rulemaking (NOPR) in the Federal Register setting forth changes in patent practice for “claims containing alternative language.” In particular, the proposed rules are directed toward changes in the presentation and examination of Markush claims, which are traditionally common in chemical practice, but can now be found in other technologies as well. Written comments on the proposed rules are being accepted until October 9, 2007. The stated purpose of the proposed rule changes is to “limit each claim to a single invention and to define acceptable formats for claims that set forth alternatives” in order to “enable the Office to do a better, more thorough and reliable examination of such claims.” The USPTO alleges that the search and examination of Markush claims, and other claims that recite alternatives (collectively referred to here as “Markush claims”) can require individual patentability considerations for each of the alternative species within a single claim, resulting in the use of a disproportionate amount of resources.

These rules are related to its recently issued final claim rules. (See Venable IP alert, September 2007; The proposed Markush rules discussed here were published before the claim rules issued on August 21, 2007.) The NOPR notes that the claim rules did not explain how the USPTO will handle Markush claims and issued this rulemaking to fill that gap. In general, the proposed rules set forth requirements resulting in a limitation on the scope of species that can be recited in a Markush claim, “encourage” applicants to explain why a Markush claim relates to a single invention, and permit the office to restrict species recited in a single claim.

Current Office practice allows presentation of a Markush claim if there is unity of invention. Unity exists among multiple chemical compounds where the compounds (1) share a common utility and (2) share a substantial structural feature essential to that utility. Unity exist for alternative process steps where (1) all members of the group possess a property in common that is mainly responsible for their function and (2) it is clear from the prior art that all of the group members possess the property. All species encompassed in a Markush claim are examined when the alternatives are sufficiently few in number or so closely related that examination can be made without serious burden. However, the Office alleges that it “cannot” refuse to examine all species in a claim that has unity of invention. Current office policy requires that, when presented with a Markush claim, examiners may require election of species for initial examination. However, if the elected species is determined to be allowable, the non-elected species must subsequently be examined, even if a separate search and examination is required for each species. The new rules provide procedures for examining claims lacking unity of invention and for restricting an application to one invention where the office determines that “multiple independent and distinct inventions are recited as alternatives in a single claim.” Among other things, the proposed rules are intended to avoid applicants circumventing the new claim rules by using Markush claim language instead of multiple claims.


The NOPR implies that the proposed rules will not affect the ability of an applicant to present and have issued generic claims. The rules do not suggest issuing a restriction in a generic claim, but do permit a requirement for an election of species for initial examination. However, if any part of a claim uses Markush language, the new rules kick in and restriction may be required. In such circumstances, the office will determine whether the members of the Markush group recite a single invention, although that task may be relatively complex.

The proposed rules specify that any claim, including a Markush claim, must be limited to a single invention (§ 1.75(a)) This condition is met when either (1) all of the species encompassed by the claim share “a substantial feature essential for a common utility” or (2) all of the species “are prima facie obvious over each other.” (§ 1.140(a)) A common feature could include a structural feature, material or act necessary for a shared specific substantial and credible utility. The rules encourage applicants filing a Markush claim to submit an explanation as to why the claim is directed to a single species. Such an explanation could identify the common feature shared by the species that is responsible for a substantial utility or explain why the group members are prima facie obvious over each other. The rules do not require an applicant to submit a statement, but provide that the office “shall” consider such a statement if filed at the time the claim is presented and “may” consider such a statement if offered after the claim is presented. (§ 1.140(b)) The proposed rules specifically state that a restriction may be made even if the plural inventions are recited as alternatives within a single claim. (§1.142(b)) Where a single claim is directed to allegedly different inventions, the claim will not be allowed until the non-elected subject matter is cancelled or it will be objected to as failing to comply with §1.75(a). (§ 1.142(d)) The rules further describe processes for traversing, requesting reconsideration of and petitioning for removal of a restriction requirement.

The rules propose adding a unity of invention requirement similar to that used in International applications during examination of US applications. Specifically, the rules allow alternative language where “each alternative within a list of alternatives must be substitutable for one another” (§ 1.75(j)(4)) and “the number and presentation of alternatives in the claim does not make the claim difficult to construe.“ (§ 1.75(j)(1))

As an additional means of simplifying examination of Markush claims, the proposed rules prohibit the presentation of a claim containing alternatives that are defined by another set of alternatives, unless there is no other practical way to claim the invention. This rule is intended to prevent difficulties in examination where overlapping alternatives makes it difficult to determine whether a claim encompasses more than one invention. Specifically, the rules set forth that:

No alternative is defined as a set of further alternatives within the claim (§1.75(j)(2)) and

No alternative is encompassed by any other alternative with a list of alternatives(§ 1.75(j)(3)).

For example, a claim may not include, as alternatives, “an adhesive agent, glue or tape” or “citrus fruit or tropical fruit.” In the first case, the second two members are completely encompassed by the first member; in the second case, there is only partial overlap. Instead of such claims, the office suggests presenting separately claims having broad scope (e.g., an adhesive agent or fruit) and claims of more narrow scope (e.g., glue or tape or citrus fruits or tropical fruits).

In one of the more oppressive aspects of the rules, the office is proposing a requirement in applications that claim priority to a prior application, but disclose subject matter that was not disclosed in the prior filed application. In such a case, the applicant must identify which claims are adequately supported under 35 U.S.C. § 112 by the earlier application. (§ 1.75(d)(2)) The USPTO asserts that this rules is imposed to simplify examination in cases where a prior art reference anticipates or renders obvious one species in a claim where the reference would not be available against another species within that claim if that species were presented in a separate claim. However, the burden on applicants and ramifications of such a statement are potentially devastating.

The manner in which the proposed rules will be applied is unclear in some circumstances and will result in difficulties with claim strategy.. This is particularly true in the chemical arts. For example, consider a base structure with two variable “R” groups. Is the base structure sufficient to impart a “substantial feature essential for a common utility?” In all likelihood, this determination may be dependent upon the circumstances of a particular application.

Thus, without clear guidance, application of this rule is potentially variable and could be the cause of considerable contention. Will the presence of two R groups within the compound be considered “alternative(s) encompassed by other alternatives(s)” or otherwise run afoul of Rule 1.75(j)?


1) When considered in conjunction with the August 21, 2007 claim rules, the proposed rules will require very careful claim drafting and consideration of strategy. Applicants should use special care in drafting Markush claims to avoid alternatives of alternatives. If the USPTO requires that some alternatives be placed in a second claim, an applicant could find themselves pushed close to the 25 claim limit.

2) Applicants should be prepared to file multiple divisional applications when an examiner objects to particular Markush groups, and may take the proactive step of filing a suggested restriction requirement. The advantage of a suggested restriction requirement is that (a) the applicant gets greater input into how the application will be divided; (b) applicants can encourage examiners to issue restriction requirements when it is advantageous to prosecute multiple claim sets, and c) a restriction will allow parallel prosecution of divisional applications with an increased number of possible continuations whereas the absence of a restriction will require serial prosecution with a smaller total number of allowable continuations.

3) Initial presentation of claims should include multiple claims with variable scope that may be subject to restriction, even if a suggested restriction requirement is not filed. If the claims are restricted in a reasonable way, divisional applications can be filed and the broad claims expanded to the allowed 25 claims. Unreasonable restriction requirements can be traversed and, if necessary, petitions can be filed. If a restriction is not issued, it may be necessary to carefully consider strategies that include the filing of continuation applications.

3) To avoid restriction, use means plus function or step plus function claims under 35 U.S.C.§ 112, ¶ 6. The NOPR states that a claim reciting “means for attaching” is a single invention treated as a generic claim and not treated as reciting multiple species. A dependent claim can present a list of particular species. On the other hand, a claim reciting “an attachment means selected from the group consisting of staples, glue and tape” would be considered as reciting alternatives and potentially subject to possible restriction.

4) Use generic claims that do not recite alternative language whenever possible. Alternatives can be presented in dependent Markush claims, but the generic claim will reduce the possibility of restriction.

5) Do not argue that members of a Markush group are patentably indistinct, substitutable or prima facie obvious over one another unless required to do so. Although the rules do not require consideration of such assertions after a claim is presented, it is hard to imagine that such arguments would not be considered if they would advance prosecution. Furthermore, it would be advantageous to wait for the examiner to allege reasons for objecting to the claim and rebut as appropriate. Making these representations prematurely is too likely to lead to estoppels. For example, arguing that species are prima facie obvious over one another, patentable indistinct or substitutable can lead to problems should a search during examination uncover art that renders a single species obvious or anticipated. If the wrong statements are made, all species could potentially fall.