The validity of a patent can be challenged in four different types of proceedings: ex parte reexamination, inter partes review, post grant review, and covered business method review. An ex parte reexamination is initiated by any person or by the PTO’s director to request that the PTO internally reexamine the claims of the patent based on prior art.
The other three proceedings were established by the America Invents Act. These proceedings are conducted by the Patent Trial and Appeal Board (PTAB) before a panel of three judges. The proceedings are adversarial;
Continue Reading Supreme Court: Federal Government Cannot Challenge Patents in PTAB

