On July 14, 2020, the Patent Trial and Appeal Board issued a decision in Ex parte Park (Appeal 2019-006050) in which a rejection over an overlapping prior art genus was determined to be insufficient to establish a prima facie case of obviousness under both a lead compound analysis and an obvious equivalents/overlapping genus analysis. In addition, the Examiner’s initial rejection of subject matter beyond the elected specie was determined to be a withdrawal of the election requirement.

For claims directed to a large genus of chemical compounds, it is very common for the Office to issue a species election that requires applicant to elect a single disclosed specie for initial examination (MPEP 803.02/809.02(a)). The MPEP explains that the elected specie should be searched first and, if the elected specie is found allowable, the claim should then be further searched to determine patentability.

In Park the Examiner made an Election of Species requirement, and Applicant elected a single compound for initial examination. However, the Examiner’s first Official Action included an obviousness rejection of the elected specie as well as other compounds within the claimed genus. Upon consideration of this rejection by the Board, the Examiner’s additional search of subject matter beyond the elected specie was found to be an “apparent withdrawal” of the election requirement by the Examiner.

With regard to the obviousness rejection itself, the Examiner applied a reference characterized as disclosing a subgenus of compounds that “encompassed” the elected specie and other compounds claimed by Applicant, and specifically cited to eight individually disclosed compounds in the reference. In supporting the conclusion of obviousness, the Examiner pointed out differences between the eight compounds and the claims, and cited to reference teachings where claimed substituents that were either missing or different in the eight exemplified compounds were described as preferred (see, e.g., pages 9-16 of the Final Rejection).

The Board found the rejection to be lacking, and reversed. First, under the “lead compound” analysis described in Otsuka Pharm. Co. v. Sandoz, Inc., 678 F.3d 1280 (Fed. Cir 2012) the Board faulted the Examiner for not identifying a specific lead compound and for providing “no reason to make the particular modification(s) required.” Under the obvious equivalents/overlapping genus analysis, the Board’s criticisms were similar, finding that “the Examiner does not establish that the selections made in the rejection were known, obvious equivalents.” Finally, citing both In re Baird 16 F.3d 380 (Fed. Cir. 1994) and In re Ruschig 379 F.2d 990 (Fed. Cir. 1967), the Board faulted the Examiner for not citing “any blaze marks [in the applied reference] directing the ordinary artisan to select either the elected species or compounds within the scope of the instant claim 1.”

Takeaways: The Park case illustrates the relatively high bar that must be met by an Examiner in rejecting compound claims for obviousness where an applied prior art genus is relatively large but encompasses the claimed compounds. In addition, because Election and Restriction requirements can have significant consequences affecting whether a child case is a continuation or a divisional, whether a Terminal Disclaimer can be required, etc., the Park case shows us that it can be important to maintain a clear prosecution record concerning the applicability of an Election/Restriction requirement, especially in cases where the benefits of such requirements are desired.

Judges: Fredman, Jenks, and Chang