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IP Alert
IP Alert: Supreme Court to Consider Assignor Estoppel

January 12, 2021

The U.S. Supreme Court granted certiorari in Minerva Surgical, Inc. v. Hologic, Inc., a case involving medical devices used to treat abnormal uterine bleeding, including continuation patents naming Csaba Truckai that were assigned to Hologic. Hologic sued Truckai’s new company, Minerva, for infringement of the continuation patents.

The issue presented to the Supreme Court is “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 District of Delaware and the Federal Circuit both ruled that Minerva’s invalidity defense was barred by the doctrine of assignor estoppel, an equitable doctrine that prevents the assignor from subsequently rendering the patent worthless. Minerva had argued that claims in the continuation patent asserted by Hologic exceeded the scope of the disclosure, and therefore were not enabled by the patents originally invented by Truckai.

The case is significant because the Supreme Court has not squarely addressed assignor estoppel. Past Supreme Court cases have generally reduced the scope of assignor estoppel, and the Court eliminated licensee estoppel in Lear, Inc. v. Adkins. The Federal Circuit recently held that assignor estoppel does not apply in the context of inter partes review proceedings in Arista Networks, Inc. v. Cisco Systems, Inc., arguably undercutting the rationale it had used to support assignor estoppel in district court litigation. The Supreme Court’s decision will settle whether assignor estoppel will continue to exist in patent litigation.

Fitch Even attorneys are monitoring this case and will report once a decision is released.

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