The US Court of Appeals for the Federal Circuit affirmed a district court judgment that the owner of a patent with claims declared unpatentable by the Patent Trial and Appeal Board (PTAB) in an inter partes review (IPR) may not challenge ir collaterally attack the decision in district court. The Federal Circuit concluded that the district court lacked jurisdiction to hear a collateral challenge attacking the validity of a PTAB final written decision. Personal Audio, LLC v. CBS Corporation, Case No. 18-2256 (Fed. Cir. Jan. 10, 2020) (Taranto, J).