This appeal arises from the first post-grant review decision issued by the PTAB based on indefiniteness under 35 U.S.C. § 112. On appeal, the Federal Circuit has been asked to determine the appropriate indefiniteness standard to be applied in post-grant review proceedings. Tinnus argues that the Board erred in applying the stricter “unclear meaning” Our Professionals Our Work Our Insights Your Finnegan Firm Careers Tools Search Blogs Articles IP Updates Podcasts Events Webinars Books Caitlin E. O'Connell Associate Washington, D.C. +1 202 408 4004 Email Lillian M. Robinson Associate Washington, D.C. +1 202 408 4169 Email standard of In re Packard, which it asserts is limited to pre-issuance claims in patent examination, not post-issuance claims in post-grant review. Tinnus argues that, instead, the PTAB should have applied the “reasonable certainty” standard articulated in Nautilus. Telebrand argues that the Board correctly applied the Packard indefiniteness standard that is applied in all other Patent Office proceedings. Telebrand asserts that the Nautilus standard is only applicable in district court litigation, where patents are entitled to a presumption of validity, and as a result, there is a higher evidentiary standard for parties seeking to invalidate a patent.