Since the Supreme Court's decision in Oil States Energy Servs., LLC, v. Greene's Energy Grp., LLC, 138 S. Ct. 1365 (2018), various constitutional challenges have continued to be raised by patent owners whose pre-AIA patents have been cancelled in AIA Inter Partes Review (IPR) proceedings. The U.S. Court of Appeals for the Federal Circuit (CAFC) has finally addressed one such challenge. In Celgene Corp. v. Peter, Appeal No. 18-1167 (Fed. Cir. July 30, 2019), the CAFC decided that the USPTO's cancellation of claims of a pre-AIA patent in AIA IPR proceedings does not constitute an unconstitutional "taking" of private property without "just compensation." In Celgene, the CAFC explained that because patents have been subject to administrative cancellation for more than 40 years on similar or substantially the same grounds as those that may be raised in an IPR, grant of a US patent has long been understood to mean: "you may enjoy and exercise your patent rights until the USPTO cancels them, or the patent expires, whichever occurs first." Thus, such cancellation does not violate the Takings Clause of the Fifth Amendment of the U.S. Constitution.