June 29, 2021
Decided June 29, 2021
Minerva Surgical Inc. v. Hologic Inc., No. 20-440
Today, the Supreme Court upheld the doctrine of assignor estoppel in patent cases, concluding in a 5-4 decision that a patent assignor cannot, with certain exceptions, subsequently challenge the patent’s validity.
Csaba Truckai co-invented the NovaSure system, a medical device that uses radiofrequency energy to perform endometrial ablations. In 1998, Truckai and his four co-inventors filed a patent application covering the NovaSure system and later assigned their interest in the patent application and any future continuing applications to Truckai’s company, Novacept. Truckai sold Novacept to Cytyc Corporation in 2004, and Hologic acquired Cytyc in 2007.
In 2008, Truckai founded Minerva and developed a new device that uses thermal energy, rather than radiofrequency energy, to perform endometrial ablations. In 2015, Hologic sued Minerva, alleging that Minerva’s device infringed one of its NovaSure patents. The district court held that the doctrine of assignor estoppel barred Minerva from challenging the patent’s validity. The Federal Circuit affirmed in relevant part, declining to abrogate the doctrine, which federal courts have applied since 1880.
May a defendant in a patent infringement action who assigned the patent, or is in privity with an assignor of the patent, have a defense of invalidity heard on the merits?
Sometimes. The doctrine of assignor estoppel survives, although it applies only when the invalidity defense conflicts with an explicit or implicit representation the assignor made in assigning her patent rights. Absent that kind of inconsistency, a defendant in a patent infringement action who assigned the patent may have a defense of invalidity heard on the merits.
What It Means:
The Court’s opinion is available here.
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