The Federal Circuit has ruled that the Patent Trial and Appeal Board (PTAB) lacks the power to invalidate claims in an inter partes review (IPR) due to indefiniteness. In a February 4 decision, the appeals court overturned an IPR final written decision in which the Board had invalidated several claims as indefinite, holding that the PTAB does not possess the statutory authority to do so. However, as to the specific IPR at issue, the Federal Circuit ruled that the PTAB should have considered the validity of certain claims under Sections 102 and 103, which the Board stopped short of doing due to its erroneous conclusion that a certain claim limitation qualified for “means-plus-function” treatment under 35 USC Section 112, paragraph six.