CAFC tackles assignor estoppel in Hologic

The outcome


These appeals require us to grapple with the doctrine
of assignor estoppel, an equitable doctrine that prevents a
party who assigned a patent to another from later challenging
the validity of the assigned patent in district court.
There are two patents-in-suit and each presents a different
assignor estoppel issue. For the first patent, we consider
whether the district court erred in holding that assignor
estoppel does not bar the assignor from relying on our
court’s affirmance of the Patent Trial and Appeal Board’s
final decision invalidating the asserted patent claims in an
inter partes review proceeding. For the second patent, we
review the district court’s summary judgment that assignor estoppel
bars the assignor from asserting invalidity
of the assigned second patent in district court. Based on
our precedent, which we are bound to follow, we conclude
that the district court did not err in either respect.



The CAFC observed


Based on our precedent and the limits it places on the
assignor estoppel doctrine, we conclude that assignor estoppel
does not preclude Minerva from relying on the Hologic decision to argue that the ’183 patent claims are void
ab initio.

We are mindful of the seeming unfairness to Hologic in
this situation. Although Minerva would have been estopped from challenging the validity of the ’183 patent
claims in district court, it was able to challenge their validity in an IPR proceeding and,
hence, circumvent the assignor estoppel doctrine. Minerva had the right to do so
under the AIA and this court’s precedent. This court has
held that the doctrine of assignor estoppel does not bar an
assignor from filing a petition for IPR. Arista Networks,
Inc. v. Cisco Sys., Inc., 908 F.3d 792, 804 (Fed. Cir. 2018).
In Arista, the patent owner argued that assignor estoppel
barred the assignor-petitioner’s IPR challenge to the patent’s validity. Id. at 798.

(...)

Generally, “when a [patent] claim is cancelled, the patentee loses any cause of action based
on that claim, and any pending litigation in
which the claims are asserted becomes moot.” Fresenius
USA, Inc. v. Baxter Int’l, Inc., 721 F.3d 1330, 1340
(Fed. Cir. 2013). Because the ’183 patent claims are invalid, Hologic cannot assert
those claims or seek ongoing
monetary or injunctive relief based on infringement. Our
affirmance of the Board’s invalidity decision in Hologic is
dispositive of the validity of the ’183 patent claims, regardless of how the validity question came to this court, and
regardless of whether assignor estoppel bars Minerva from
challenging the patent’s validity in this district court case.




Of the '348 patent


Although we recognize that assignor estoppel is not a
“broad equitable device susceptible of automatic application,” Diamond Sci., 848 F.2d at 1225–26, we agree with
the district court that the equities weigh in favor of its application in this case. The facts here are analogous to those
in Diamond Scientific, Shamrock, and other cases in which
an inventor executes broad assignments to his employer,
leaves his employer, founds or takes on a controlling role
at a competing company, and is directly involved in the
alleged infringement. Minerva disputed none of the pertinent facts below or on appeal. Mr. Truckai “executed a
broad assignment of his patent rights to NovaCept and
later sold NovaCept to Hologic’s predecessor for $325 million.” Summary Judgment Op., 325 F. Supp. 3d at 524.
Thus, NovaCept “received appreciable value” for the patents at issue. Mentor Graphics, 150 F.3d at 1378.
Mr. Truckai then “founded Minerva” and “used his expertise to research, develop, test, manufacture, and obtain regulatory approval for the Minerva EAS.” Summary
Judgment Op., 325 F. Supp. 3d at 523. Mr. Truckai’s “job
responsibilities as Minerva’s President and CEO included
bringing the accused product to market to directly compete
with Hologic.” Id.