In 2018, Hunting Titan, Inc. filed a petition for inter partes review (“IPR”) of U.S. Patent No. 9,581,422 (“the ’422 patent”), which is owned by DynaEnergetics Europe GmbH, a manufacturer of industrial explosives. In pertinent part, Hunting Titan asserted in its petition that claims 1-15 of the ’422 patent were unpatentable because they were anticipated by U.S. Patent No. 9,689,223 to Schacherer et al. (“Schacherer”). After the Patent Trial and Appeal Board (“the Board”) instituted the IPR, DynaEnergetics moved to amend the ’422 patent to add proposed substitute claims 16-22. In opposing DynaEnergetics’s motion to amend, Hunting Titan advanced grounds based only on obviousness, not anticipation. The Board found for Hunting Titan and determined that all of the original claims of the ’422 patent, as well as the proposed substitute claims, were unpatentable as anticipated by Schacherer.[1]

DynaEnergetics requested that the Precedential Opinion Panel (“POP”) rehear and review the Board’s denial of the motion to amend. In particular, DynaEnergetics asked the POP to review the circumstances under which the Board may raise a ground of unpatentability against substitute proposed claims in a motion to amend, when said ground was insufficiently developed or not advanced by the petitioner. In its review, the POP concluded that “only under rare circumstances should the need arise for the Board to advance grounds of unpatentability to address proposed substitute claims that the petitioner did not advance, or insufficiently developed, in its opposition to the motion.” The POP vacated the Board’s denial of DynaEnergetics’s motion to amend, found that Hunting Titan had not shown by a preponderance of the evidence that substitute claims 16-22 were unpatentable, and granted the motion to amend the ’422 patent.

Both parties appealed to the Court of Appeals for the Federal Circuit (“the CAFC”). Hunting Titan appealed the POP’s decision to vacate the Board’s decision denying the motion to amend. DynaEnergetics cross-appealed the Board’s finding that the original claims were anticipated by Schacherer.

CAFC Decision

After affirming the Board’s finding of anticipation with respect to original claims 1-15, the CAFC turned to the larger issue of the POP’s decision to grant DynaEnergetics’s motion to amend.

Hunting Titan contended that the Board had a duty to determine, sua sponte (essentially, on its own initiative), whether the substitute claims were patentable based on the whole record, and that it was an error for the POP to vacate the Board’s decision. The CAFC acknowledged that the Board has a duty to sua sponte raise patentability challenges to proposed substitute claim, but the court stopped short of saying whether the Board must sua sponte raise patentability challenges for amended claims. The CAFC also found it “problematic” that the POP stated the Board should raise patentability issues sua sponte in only “rare” circumstances, and it emphasized the “basic purpose of IPR proceedings: to reexamine an earlier agency decision and ensure ‘that patent monopolies are kept within their legitimate scope.’”

The CAFC agreed with the POP that the Board should advance grounds of unpatentability that a petitioner did not advance or insufficiently developed if the evidence is “readily identifiable.” It noted that the POP highlighted “readily identifiable evidence” as being a situation “where the record readily and persuasively establishes that substitute claims are unpatentable for the same reasons that corresponding original claims are unpatentable.” It seemed to indicate that anticipation based on Schacherer would fall into this “readily identifiable evidence” category. However, on appeal, Hunting Titan did not challenge the POP’s decision to consider only evidence of unpatentability advanced by Hunting Titan in its opposition to DynaEnergetics’s motion to amend. Because Hunting Titan did not challenge that decision, the CAFC ruled the challenge forfeit.

Therefore, the CAFC affirmed the POP’s decision granting the motion to amend, but it emphasized that the affirmance was to be narrowly construed. It further noted that it was not determining the patentability of the proposed substitute claims, nor was it deciding whether the POP abused its discretion in determining anticipation by Schacherer was not readily identifiable. Additionally, the CAFC clarified that it was not making a determination as to whether the Board has an obligation to, sue sponte, determine patentability of proposed substitute claims.


With the issue of sua sponte rejections of substitute claims still an open question, both petitioners and patent owners should take care whenever the issue arises before the Board. Petitioners should be scrupulous about what unpatentability grounds they wish to bring in their opposition motions, while patent owners should be wary that the Board may still sua sponte reject their proposed substitute claims in light of readily identifiable evidence.

[1] IPR2018-00600.