Last October, the Federal Circuit held in Arthrex that the appointment of administrative patent judges (APJs) by the Patent Trial and Appeal Board (PTAB) is unconstitutional, casting doubt on numerous invalidity proceedings and related appeals as a result. Indeed, an RPX analysis indicates that hundreds of America Invents Act (AIA) reviews may be subject to rehearing in light of that decision. Now, the appeals court has declined to rehear the case en banc, following months of appellate briefing in this litigation and a companion appeal that saw the US government file briefs in both cases. The denial of the petition for en banc review sparked further debate within the Federal Circuit, with two concurrences and three dissents filed along with the court’s order.