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PTAB allows Amending Claims on Grounds not raised by Petitioner, but were Addressed by the District Court in its Finding of Indefiniteness

To amend challenged claims during an Inter Partes Review (IPR), the patent owner must show that the proposed amendment responds to a ground of unpatentability at issue in the IPR trial.  But in a recent final written decision in Intuitive Surgical Inc. v. Ethicon LLC, IPR2018-00933, Paper No. 31 (Dec. 3, 2019), the Patent Trial and Appeal Board (PTAB) allowed amended claims that included amendments addressing indefiniteness problems not asserted as an unpatentability ground in the IPR.  This potential avenue for amending claims should be considered by both patent owners and petitioners alike. 

Indefiniteness may not be asserted as a ground for unpatentability in an IPR.  Thus, when Intuitive Surgical filed its IPR Petition challenging Ethicon’s U.S. Patent No. 9,084,601, the Petition included no indefiniteness grounds, but instead asserted that the challenged claims were unpatentable in light of prior art.  Likewise, when the PTAB instituted the requested IPR, it did not institute on any indefiniteness grounds. 

After institution, however, in a parallel district court case between Intuitive and Ethicon concerning the ʼ601 patent, the District Court of Delaware found that the challenged claims were invalid because they included a claim term that was indefinite.  Thereafter, in the ongoing IPR, Ethicon filed a motion to amend the challenged claims, proposing not only amendments that addressed the prior art patentability grounds asserted in the IPR, but also additional amendments that addressed and attempted to cure the Delaware Court’s indefiniteness ruling. 

In order for a patent owner to meet the statutory and regulatory requirements to amend its claims, it must demonstrate that: (1) the number of proposed claims is “reasonable,” (2) the amendment responds to a ground of unpatentability involved in the trial, (3) the proposed amendment does not enlarge the scope of the claims, and (4) the proposed amendment does not introduce new matter.  See 35 U.S.C. § 316(d) (2019); 37 C.F.R. § 42.121.  In response to Ethicon’s motion to amend, Intuitive Surgical did not dispute that the amended claims were responsive to the grounds of patentability.

The PTAB allowed the motion to amend, finding that one set of amendments overcame the prior art grounds and that the other “adequately addresse[d] the District Court’s [indefiniteness] concerns.”  When addressing the requirement that the amendment must respond to a ground of unpatentability involved in the IPR trial, the PTAB concluded this requirement was met because the proposed amendments included an additional limitation that was not present in the asserted prior art, and Petitioner did not dispute that the proposed substitute claims were responsive to the ground of unpatentability.  The PTAB did not address whether any additional amendments were or needed to be responsive to a ground of unpatentability. 

Since the Federal Circuit’s en banc ruling in Aqua Products Inc. v. Matal, there has been an upward trend in the PTAB allowing patent owners to amend claims.  While patent owners are allowed to amend their claims in response to grounds of unpatentability involved in trial, this final written decision suggests that patent owners may go a step further and include additional amendments that address non-IPR issues.  Patent Owners should be on the lookout for opportunities to strengthen their challenged claims in this manner, while Petitioners should consider challenging such proposed amendments as not responding to a ground of unpatentability raised in the IPR.


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William A. Meunier is a Mintz attorney who has mastered inter partes review (IPR) proceedings and high-stakes patent litigation. He has helped patent owners achieve success in over 90% of IPRs, compared to the industry average of only 35%. Bill has decades of experience litigating patent cases.