Stepping through a door it opened last year, the U.S. Court of Appeals for the Federal Circuit ruled Friday that states do not enjoy sovereign immunity from inter partes review (IPR). Unless overturned by the Supreme Court, the Federal Circuit's unanimous decision in Regents of the University of Minnesota (UMN) v. LSI Corp. could make it a lot easier, and cheaper, to challenge foundational drug and device patents stemming from state-owned university research.