Table of Contents

Infringement Defenses

Assignor Estoppel Doctrine still with us (updated 06/30/21)

Assignor Estppel is “an ecquitable doctrine that prevents one who has assigned the rights to a patent (or patent application) from later contending that what was assigned is a nullity.” Diamond Sci.1)

The Supreme Court, in a 5-4 vote, decided to keep Assignor Estoppel with us a while longer, but stated that the Federal Circuit has applied the doctrine too broadly. The crux of the ruling is this: “The doctrine applies when, but only when, the assognor's claim of invalidity contradicts explicit or implicit representations he made in assigning the patent.”

It is worth noting that the Supreme Court was apparently influenced by Mark Lemly's amicus brief, and in fact cited Lemly's Houston Law Review article, “Rethinking Assignor Estoppel2)) (private cache) in two places in the majority opinion.

Procedural History

Inventor Csaba Truckai of two Hologic patents (6,872,183 and 9,095,348) initially assigned the invention (priority applications) to a company he co-founded called “NovaCept, Inc.” NovaCept was later acquired by Cytyc Corporation and Hologic later acquired Cytyc. The following year, Truckai left NovaCept and founded the accused infringer, Minerva, who filed IPR petitions challenging the patentability of the patents. The Board held that the '183 patents are unpatentable as obvious. Hologic moved for summary judgment that the doctrine of assignor estoppel bars Minerva from challenging the validity of the '183 and '348 patent claims, which the district court granted. The Federal Circuit upheld the IPR decisions on appeal. The district court stated that the ~$5M judgment against Minerva is not affected by the IPR or the Circuit's decision on appeal because of the findings of assignor estoppel.

In Hologic, Inc. v. Minerva Surgical, Inc., the Federal Circuit held:

  • The primary justification for the doctrine is “unfairness and injustice.”
  • The court has limited the doctrine in certain instances:
    • “Although estopped parties cannot challenge the validity of the patent at issue, assignor estoppel does not limit their ability to defend themselves in other ways, including arguing that the patentee is itself collaterally estopped from asserting a patent found invalid in a prior proceeding.”
    • Also, “an estopped party may argue for a narrow claim construction, or that the accused devices are within the prior art and therefore cannot infringe.”
  • In this case, assignor estoppel does not preclude Minerva from relying on the Hologic decision (that upheld the IPR invalidity) to argue that the '183 claims are void ab initio. Thus, [. . ..] Minerva had the right to [file the IPR] under the AIA and this court's precedent [in Arista Networks Inc. v. Cisco Sys., Inc. 3)].“
  • In Diamond Scientific, we recognized that some courts questioned the vitality of the assignor estoppel doctrine following the Supreme Court’s decision abolishing licensee estoppel in Lear, Inc. v. Adkins, 4). We concluded, however, that nothing in Lear eliminated assignor estoppel.

Supreme Court Review

Oral Hearing

As reported by Law360, in oral arguments on April 21, 2021, Justices Kavanaugh and Sotomayor expressed skepticism of disturbing such a “well settled” legal principle.

Blogs

Background: On January 8, 2021, the Supreme Court granted certiorari for review on the question:

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.

The petition for writ attracted many interested amici, including a brief submitted by Mark Lemley of Stanford University, who argued that the Federal Circuit's interpretation is broader than Supreme Court precedent, and needs to be narrowed. Specifically, the Federal Circuit's precedent:

  1. “reaches well beyond the assignor to bar validity charges by a wide range of parties in privity with assignors”
  2. “extends beyond cases where an inventor knowingly and voluntarily transfers a patent” and “is not limited to cases where an inventor or assignor misrepresents a patent's validity, or indeed makes any representation or warranty at all about the patent”
  3. “applied assignor estoppel where the assignee amended the claims in a patent after assignment to cover things the inventor never intended” noting ”that is what happened here“ (emphasis added).

Supreme Court Holdings:

Minverva Surgical Inc. v. Hologic Inc. (booklet) (case 20-440) was decided June 29, 2021. Five Justices, led by Kagan and joined by Roberts, Breyer, Sotomayor, and Kavanaugh, wrote the following holdings. (In the below quotes, citations are removed.)

Dissents

Justice Alito wrote a dissent focusing on the “evasion” of stare decisis by the Court and the principal dissent. Stated Alito: “I do not think we can decide the question that the petition in this case presents unless we decide whether Westinghouse should be overruled. Because the majority and the principal dissent refuse to decide whether Westinghouse should be overruled, I would dismiss the writ as improvidently granted.” In apparent response to this argument, the Majority held, “we do not think . . . that contemporary patent policy–specifically, the need to weed out bad patents–supports overthrowing assignor estoppel. In rejecting that argument, we need not rely on stare decisis: '[C]orrect judments have no need for that principle to prop them up.' Kimble v. Marvel Entertainment, LLC.

Justice Barrett, joined by Thomas and Gorsuch wrote a further dissent that argued that “this case turns on whether the Patent Act of 1952 incorporates the doctrine [of assignor estoppel], and held that the doctrine of assignor estoppel, previously held as being incorporated into the Patent Act of 1870, was not carried over into the Patent Act of 1952.

Blogs

~NOTERED~ THIS IS A WORK IN PROGRESS..

Alito
Alito
Barrett
Barrett
Breyer
Breyer
Gorsuch
Gorsuch
Kagan
Kagan
Kavanaugh
Kavanaugh
Roberts
Roberts
Sotomayor
Sotomayor
Thomas
Thomas
Alito Barrett Breyer Gorsuch Kagan Kavanaugh Roberts Sotomayor Thomas
Op., Part I; history of patent administration and this case Joined Joined Joined Joined Authored
Op., Part II; precedent of Edmund; failures of Thomas' dissent; “the unreviewable authority wielded by APJs during [IPR] is incompatible with their appointment by the Secretary as inferior officers [under the Appointments Clause]. Joined Joined Joined Joined Authored
Op., Part III; Joined Joined Authored

1)
848 F.2d at 1224
2)
54 Houston L. Rev. 513 (2016
3)
908 F.3d 792, 804 (Fed. Cir. 2018
4)
395 U.S. 653, 666 (1969)