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On Friday the Supreme Court granted the petition for certiorari in Minerva Surgical, Inc. v. Hologic, Inc., a patent infringement case decided by the Federal Circuit in April of last year. In this case, the petitioner asks the Court to abandon or limit the doctrine of assignor estoppel, which prevents a party who in the past assigned a patent from later contesting the patent’s validity. Here are the details.

In another case decided in 2018, the Federal Circuit ruled that the doctrine of assignor estoppel does not apply in the context of inter partes review proceedings. This holding created a “dual-track system” in which the doctrine applies differently in the Patent Office and in district courts. While it does not apply at the Patent Office, it does apply in district courts.

In this case, the Federal Circuit followed its precedent in both contexts. It concluded that assignor estoppel does not apply at the Patent Office, but that it does apply in district court. Both parties petitioned the Supreme Court. Notably, the author of the Federal Circuit’s opinion in this case, Judge Stoll, filed an opinion with additional views suggesting “that it is time for this court to consider en banc the doctrine of assignor estoppel as it applies both in district court and in the Patent Office.” She went on to explain that, in her view, the court “should seek to clarify this odd and seemingly illogical regime in which an assignor cannot present any invalidity defenses in district court but can present a limited set of invalidity grounds in an IPR proceeding.” In July, however, the Federal Circuit denied en banc rehearing.

At the Supreme Court, Minerva in its petition and Hologic in its cross-petition agreed that the law of assignor estoppel has produced intolerable inconsistencies. The parties, however, disputed which petition properly presented the issue to the Court.

Minerva’s petition presented the question as “whether a defendant in a patent infringement action who assigned the patent, or is in privity with an assignor of the patent, may have a defense of invalidity heard on the merits.” Notably, Minerva received support from two separate amicus groups: a group of Intellectual Property Professors and Engine Advocacy, a non-profit technology policy, research, and advocacy organization.

Hologic’s cross-petition, on the other hand, presented the question as “Whether an assignor of a patent may circumvent the doctrine of assignor estoppel by challenging the validity of the assigned patent in administrative proceedings before the Patent Office, and then using the Patent Office’s finding of invalidity to collaterally estop the assignee from relying on the patent in infringement litigation in district court.”

On Friday, the Court granted review of Minerva’s question. Significantly, today the Court denied Hologic’s cross-petition. It remains to be seen whether this is a harbinger of the elimination of assignor estoppel in district court rather than its application at the Patent Office. Either way, the Court will soon address the assignor estoppel doctrine and the Federal Circuit’s forum-based diverging precedent on its application.

We will continue to monitor this case and report on developments.