The question of whether PTAB trials are litigation-like or examination-like (or some hybrid of the two) has been implicated on several occasions.  The most recent one is in the In re Aqua en banc hearing Order.  No. 2015-1177 (Fed. Cir. Aug. 12, 2012).  While the PTAB has repeatedly stated it does not examine proposed amended

On July 25, 2016, in In re Magnum Oil Tools Int’l, Ltd., Case No. 2015-1300, the Federal Circuit clarified the respective burdens carried by both the petitioner and the patentee in an inter partes review proceeding. The court reversed the Board’s decision that the challenged claims of U.S. Patent No. 8,079,413, directed to oil