In Ex parte VIKTOR DUBOVOY, IRENEPETROU, and LONGPAN the patent trial and appeal board (PTAB) found that this was not analogous prior art and therefore reversed the decision of the Examiner who had rejected claims directed towards an oral care composition comprising a zirconium oxychloride cluster in view of U.S. Patent No. 4,148,812 to Rubino.

          In its decision the PTAB stated: “[T]he purpose of the analogous art test is to examine whether a reference can be considered as prior art to the [patent application] in the first place.” Sanofi-Aventis Deutschland GmbH v. Mylan Pharm. Inc., 66 F.4th 1373, 1377 (Fed. Cir. 2023). “In order to rely on a reference as a basis for rejection of the applicant’s invention, the reference must either be in the field of the applicant’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned.” In re Oetiker, 977 F.2d 1443, 1447 (Fed. Cir. 1992).  Here, Appellant’s Specification explains that the field of the endeavor is reducing sensitivity of teeth to “a variety of stimuli, including thermal, tactile, [etc.] stimuli.” Spec. ¶ 2. The Specification states that, “[c]onventionally, two approaches have been taken to treat or ameliorate tooth sensitivity. The first approach is to interfere with transmission of nerve impulses” using chemical desensitizing agents. Id. ¶ 3. “The second approach involves the mechanical shield of the nerve by, e.g., blocking of the dentin tubules wholly or partially with dentin tubule occlusion agents.” Id. The field of endeavor of Rubino ’812, by contrast, is “antiperspirant systems.” Rubino ’812, abstract. Endeavoring to reduce skin perspiration is directed to a different objective in a different part of the body from endeavoring to reduce tooth sensitivity. The PTAB stated: “We agree with Appellant that antiperspirants are not within the field of Appellant’s endeavor. And the problem addressed by Rubino ’812 has not been shown to be reasonably pertinent to the problem faced by the instant inventors.”

          Therefore, patent applicants should take care to draft applications which take into mind the field of the endeavor, so that this field when crafted can be used to avoid prior art rejections to non-analogous art.