In Microsoft Corp. v. Proxyconn, Inc., Nos. 14-1542, -1543 (Fed. Cir. June 16, 2015), the Federal Circuit addressed two aspects of inter partes review (IPR) proceedings: (1) the broadest reasonable interpretation standard and (2) requirements for amending claims. First, the Court affirmed the Board’s use of the broadest reasonable interpretation standard, relying on its decision in In re Cuozzo Speed Techs, LLC, 778 F.3d 1271 (Fed. Cir. 2015). The Court cautioned, however, that claim interpretation under this standard cannot be unreasonably broad and must reasonably reflect the plain language and disclosure.

With respect to the requirements for amending claims during IPR, the Court affirmed the Board’s decision to require a showing that the amended claims are patentable over all prior art of record—not just prior art that the Board relied upon when instituting review. The Court explained that if the patentee were not required to establish patentability over all prior art of record, the amended claims could issue even though the PTO had before it prior art that undermined the patentability of the amended claims.