In a Petition for Inter Partes Review, a petitioner may challenge patent claims as being anticipated and/or obvious. 35 U.S.C. §311(b). A challenge based on 35 U.S.C. §112, such as indefiniteness, is unavailable. However, indefiniteness may become an issue during claim construction, particularly for means-plus-function limitations.

In nearly a dozen cases, the PTAB has denied institution because it found that the petitioner did not show a limitation to be definite. In certain of those cases, the PTAB has concluded that “Petitioner has not demonstrated that the recitation of [a limitation]… viewed in light of the specification and prosecution history, sufficiently informs those skilled in the art about the scope of the invention with reasonable certainty,” and thus “has not shown a reasonable likelihood that it would prevail.”Medshape, Inc. v. Cayenne Medical, Inc., IPR2015-00848 (Sept. 14, 2015) (Paper 9) at 11-12. InMedshape, the PTAB applied the Supreme Court’s opinion in Nautilus, Inc. v. Biosig Instruments, Inc., 134 S.Ct. 2120, 2124 (2014), that a claim is indefinite if it fails to inform, with reasonable certainty, about the scope of the invention. Id. at 8.

While Medshape failed to institute a recent IPR against certain claims, it was recently able to obtain a summary judgment ruling of invalidity in a parallel district court proceeding. Cayenne Medical, Inc. v. Medshape, Inc., No. 2.14-cv-0451, slip op. at 15 (D. Ariz. May 6, 2016). In particular, the district court found the PTAB’s finding of indefiniteness to be compelling evidence of invalidity in that particular case. Id. at 8. This appears to be the first district court finding of indefiniteness based on a PTAB decision.

This contrasts with Fortinet v. Sophos, where the district court reached the opposite conclusion under similar facts. Based on the PTAB’s denial of institution for indefiniteness in Fortinet, Inc. v. Sophos, Inc., IPR2015-00617 (August 13, 2015) (Paper 9) at 18-19, Fortinet sought summary judgment of invalidity before the district court. Fortinet, Inc. v. Sophos, Inc., 2015 U.S. Dist. LEXIS 146317, at *13 (N.D. Cal. Oct. 28, 2015). There, the Court found a lack of clear and convincing evidence that the claims were indefinite. Id. at *25-26. While the Court found the PTAB decision “persuasive” in some aspects, it emphasized that the decision was “not binding in any way,” and that “the PTAB was not asked to invalidate based on indefiniteness.” Id. at *28 & n.4.

The differences in outcome may reflect several variables regarding these decisions. First, a PTAB decision is not binding on a district court. Second, the PTAB found the petitioner to have failed to establish the term to be definite; not that Petitioner established indefiniteness. Third, different panels may reach different conclusions on the issue of a claim’s definiteness. Compare IPR2014-01170 (no institution) with IPR2015-01872 (institution). Finally, the PTAB decisions were only one factor considered by either Court.