The US Court of Appeals for the Federal Circuit reiterated that
while assignor estoppel prevents a party that assigned a patent to
another party from later challenging the validity of the assigned
patent in district court, it does not preclude the party from
challenging the validity of the assigned patent in an America
Invents Act inter partes review (IPR) proceeding.
Hologic, Inc. v. Minerva Surgical, Inc., Case Nos.
19-2054; -2081 (Fed. Cir. Apr. 22, 2020) (Stoll, J.) (Stoll, J.,
additional views).
Csaba Truckai co-founded NovaCept and developed the NovaSure
system. Hologic subsequently acquired NovaCept along with two
patents it owned relating to endometrial ablation. Truckai later
founded Minerva and developed a system to compete directly with
Hologic's NovaSure system, which led to Hologic suing Minerva
for infringement of the two patents. Minerva challenged the
patents, both in district court and by filing IPR petitions. The
district court found that assignor
