Estoppel: putting a stop to repeat offenders

The 2011 America Invents Act (AIA) brought post-grant oppositions to the US patent system. These proceedings are referred to as inter partes review (IPR), post-grant review (PGR) and covered business method review (CBM). The desire was to create faster and less expensive alternative pathways for challenging patents using the US Patent and Trademark Office (USPTO) as the forum. The predecessor pathways of ex parte and inter partes reexamination were considered insufficient because these proceedings proved to be time-consuming and did not offer discovery.