On June 16, 2015, the Federal Circuit upheld the Cuozzo decision (778F. 3d. 1271) applying the broadest reasonable interpretation standard of claim construction to IPR proceedings. However, the Federal Circuit held that the PTAB had applied an unreasonably broad interpretation. Microsoft Corp., v. Proxyconn, Inc., No. 2014-1542, -1543 (Fed. Cir. June 16, 2015). The Federal Circuit often uses Rule 36 to summarily affirm the Board without a written decision, so this decision was notable.

In particular, the PTAB’s interpretation of the term “two other computers” to include caching computers, and the interpretation of “sender/computer” and “receiver/computer” to encompass separate intermediary gateway and caching computers, were held to be unreasonably broad.

The Federal Circuit also affirmed the Board’s denial of Proxyconn’s motion to amend claims, specifically affirming the requirement for the patent owner to show that the amended claims are patentable over the prior art of record. However, the court noted that it was not addressing the requirement to show patentable distinction over all prior art known to the patent owner.