In ABS Global, Inc. v Cytonome/ST, LLC, the Federal Circuit dismissed a Petitioner’s appeal from a U.S. Patent Trial and Appeal Board (“PTAB”) final written decision when it determined that a Patent Owner’s voluntary cessation in its district court action mooted the PTAB case. Specifically, after Patent Owner disclaimed its ability to challenge a finding of non-infringement in a related district court proceeding, the Federal Circuit determined that “[b]ecause the record demonstrates that there is no longer a live case or controversy between the parties, [Petitioner’s/Appellant’s] IPR appeal is moot.”[i]

We begin unweaving the parallel proceedings by providing a condensed procedural posture for the case at the Federal Circuit:

  • June 2017 (District Court)– Cytonome/ST, LLC (“Cytonome”), Inguran, LLC, and XY, LLC filed a complaint against ABS Global, Inc. (“ABS”) in district court, alleging infringement of claims in six patents, including U.S. Patent No.: 8,529,161 (the “’161 patent).
  • October 2017 (PTAB) – ABS filed a petition for inter partes review of all claims of the ’161 patent.
  • April 2019 (PTAB) – The PTAB issued a final written decision holding several claims not unpatentable (i.e., valid), while also finding some claims unpatentable.
  • April 2019 (District Court) – Two weeks after the PTAB’s final written decision, the district court granted, in part, ABS’s motion for summary judgment, concluding that ABS’s accused products did not infringe any of the ’161 patent claims.
  • June 2019 (PTAB, Federal Circuit) – Petitioner ABS filed a notice of appeal from the PTAB’s final written decision.
  • September 2019 (District Court) – The district court held a jury trial covering patents remaining in the case.
  • November 2019 (Federal Circuit) – ABS filed its opening blue brief challenging the aspects of the Board’s final written decision that found it failed its burden of proving unpatentability.
  • February 2020 (Federal Circuit) – Cytonome filed a response red brief, including an affidavit by Cytonome’s counsel that it “has elected not to pursue an appeal of the district court’s finding of non-infringement as to the ’161 patent and hereby disclaims such an appeal.”[ii] The brief argued that, because it “disavowed its ability to challenge the district court’s summary judgment that ABS did not infringe the ‘161 patent claims, ABS lacked the requisite injury in fact required for Article III standing to appeal the Board’s final written decision regarding validity of the claims of the ’161 patent.”[iii]
  • April 2020 (Federal Circuit) — ABS responded that “mootness, not standing, provides the proper framework to assess jurisdiction” of the case and that its appeal is not moot under a “purported patent-specific exception to the mootness doctrine set forth in Fort James Corp. v. Solo Cup Co., 412 F.3d 1340 (Fed. Cir. 2005).”[iv]

In the Federal Circuit majority decision, Judge Stoll applied the doctrine of voluntary cessation to dismiss ABS’s PTAB appeal as moot. Specifically, Judge Stoll determined that “Cytonome has demonstrated that its challenged conduct is not reasonably expected to recur, and that ABS has failed to demonstrate that it is engaged in or has sufficiently concrete plans to engage in activities not covered by Cytonome’s disavowal.”[v] The Court further explained that Cytonome’s disavowal estops it from asserting the ’161 patent against the accused ABS products or any ABS products that are “essentially the same” as the accused products.[vi]

Judge Stoll further determined that Fort James stands for the principle that a district court has the power to decide questions posed in alternative grounds for relief (non-infringement rather than invalidity) when its decree was subject to review by a court of appeal. Fort James is therefore inapplicable to the instant case because a “determination of invalidity in ABS’s IPR proceeding . . . could not provide an alternative ground for the district court’s judgment against Cytonome in an entirely different proceeding.”[vii]

Finally, ABS argued, for the first time at oral argument, that if the Federal Circuit were to find the case moot, “vacat[ing] the challenged portion of the [Board’s] decision” would be proper.[viii] Judge Stoll declined ABS’s vacatur request, stating that “wait[ing] over seven months to raise vacatur, requesting it for the first time at oral argument” and failing to “explain why vacatur would be the appropriate remedy either at oral argument or by seeking permission to file supplemental briefing,” constituted forfeiture.[ix]

Practice Tips:

First, PTAB Parties need to be aware of the doctrine of voluntary cessation and the effects that it may have on a right to appeal, including the possibility that such a district court disavowal may cement a PTAB victory (or defeat).

Second, Parties should also consider the possible effects of a timely request during PTAB appeal for vacatur after a voluntary district court cessation is made. While it is true that, although the Supreme Court “normally do[es] vacate the lower court judgment in a moot case,” Judge Prost argues, in dissent, that this rule is not absolute.[x] Indeed Judge Prost, argues that “[v]acatur is in order when mootness occurs through happenstance—circumstances not attributable to the parties—or, relevant here, the ‘unilateral action of the party who prevailed in the lower court.’”[xi] Judge Prost’s dissent continues, “[t]his appeal was not mooted by mere happenstance but by the unilateral act of an adversary to cement its victories below.”[xii] Vacatur, Judge Prost argues, avoids this unfairness.[xiii]


[i] ABS Global, Inc. v. Cytonome/ST, LLC., Appeal No. 2019-2051, slip op. 6 (Fed. Cir. 2021).

[ii] Id. at 2.

[iii] Id. at 3.

[iv] Id. at 3-4 (citing Fort James Corp. v. Solo Cup Co., 412 F.3d 1340 (Fed. Cir. 2005)).

[v] Id. at 4.

[vi] Id. at 8-9 (citing Brain Life, LLC v. Elekta Inc., 746 F.3d 1045, 1058 (Fed. Cir. 2014) and SpeedTrack, Inc. v. Office Depot, Inc., 791 F.3d 1317, 1323 (Fed. Cir. 2015)).

[vii] Id. at 16.

[viii] Id. at 17.

[ix] Id.

[x] Id. at 22 (Prost, dissenting).

[xi] Id. at 21 (Prost, dissenting).

[xii] Id. at 23 (Prost, dissenting).

[xiii] Id. at 21 (Prost, dissenting).


This article appeared in the January 2021 issue of PTAB Strategies and Insights. To view our past issues, as well as other firm newsletters, please click here.

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