Well perhaps not the mass hysteria that Dr. Venkman anticipated in Ghostbusters, but the granting of a motion to amend is still an unusual occurrence.  However, in Riverbed Technology Inc. v. Silver Peak Systems, Inc., IPR2013-00402, Paper 35 (December 30, 2014), the Board granted patent owners motion to cancel the claims in the proceeding, and to add substitute claims 13 and 15.  That the substitute claims did not enlarge the claim scope and were adequately supported by the specification was not contested.  However, the patent owner also bears the burden of proof to demonstrate patentability of its proposed substitute claims over the prior art.  The Board explained:

This does not mean that the patent owner is assumed to be aware of every item of prior art known to a person of ordinary skill in the art. However, the patent owner should explain in its motion why the proposed substitute claims are patentable over not just the prior art of record, but also prior art not of record but known to the patent owner:

The Board found patent owner’s explanation as to why the proposed substitute claims are different from pre-existing data de-duplication systems was both persuasive and supported by the evidence of record.  The Board noted that the patent owner accounted for the knowledge of a person of ordinary skill in the art.  The Board disagreed with petitioner’s arguments that the patent owner did not address prior art beyond that involved in the proceeding, and rejected petitioner’s complaint that patent owner failed to identify the level of skill in the art or provide supportive expert testimony, noting that expert testimony is not required.

The Board, however, declined to grant patent owner’s motion to substitute amended dependent claims.  The Board noted that the only amendments permitted are those responsive to the grounds of unpatentability raised in the petition. The patent owner argued that these amended dependent claims were allowable for the same reasons as the amended claims from which they depend, but this ran afoul of the presumption that only one substitute claim was permitted for each cancelled claim.  Even in the rare instances where amendment during inter partes review is permitted, a motion to amend is still a very blunt tool for patent owners trying to protect the invention.

Two other substitute claims were denied under §101.  Although  §101 is not a proper grounds for an IPR, a patent owner nonetheless bears the burden of establishing the patentability of amended claims.