Jun 29, 2021Legal
SUPREME COURT RULING: Minerva Surgical, Inc. v. Hologic, Inc., June 29, 2021


Minerva Surgical, Inc. v. Hologic, Inc., et al, No. 20-440 (S. Ct. June 29, 2021)

The Supreme Court issued a decision today upholding the validity of the doctrine of assignor estoppel and clarifying its proper limits. The Court held that the doctrine only applies when “the assignor’s claim of invalidity contradicts explicit or implicit representations he made in assigning the patent.”

The invention at the core of this lawsuit is a device called the NovaSure System that is used to treat abnormal uterine bleeding. Csaba Truckai, the founder of the company Novacept, Inc., invented the device and filed a patent application, assigning his interest in the application to Novacept. The patent description emphasized the water-permeability of the device’s applicator heads that help to remove fluid during treatment. In 2007, Hologic, Inc. acquired the patent rights in the NovaSure System.

In 2008, inventor Truckai founded Minerva Surgical, Inc. and developed a “supposedly improved device” to treat abnormal uterine bleeding. Minerva’s device, unlike the NovaSure System, is “moisture impermeable” as it does not remove fluid during treatment. The PTO issued a patent for the device. In 2013, Hologic filed a continuation application requesting to add claims for its NovaSure System patent. “Aware of Truckai’s activities, Hologic drafted one of those claims to encompass applicator heads generally, without regard to whether they [were] moisture permeable.” The PTO issued the continuation patent with the requested alteration.

Shortly thereafter, Hologic sued Minerva for patent infringement. Minerva asserted that Hologic’s amended patent was invalid because “the new, broad claim about applicator heads [did] not match the invention’s description, which addresse[d] their water-permeability.” Hologic invoked the doctrine of assignor estoppel, arguing that Truckai, and therefore Minerva, could not attempt to impeach the patent’s validity because he filed and assigned the original patent application to Hologic’s predecessor. The district court agreed and held that the doctrine of assignor estoppel barred Minerva’s invalidity defense. The Federal Circuit upheld the judgment with respect to the doctrine of assignor estoppel. The Supreme Court granted certiorari to consider whether to uphold the doctrine of assignor estoppel, and if so, to determine the limitations of its use.

Read the Case.

By Annie White

Edited by: Scott D. Eads and Nika Aldrich, Schwabe Williamson & Wyatt

Contributor: Annie White

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