Minerva Surgical, Inc. v. Hologic, Inc.
Headline: Court upholds assignor estoppel but limits it, letting inventors challenge patent claims broadened after a sale and affecting inventors, buyers, and medical-device makers.
Holding: The Court held that inventors who sell patent rights can be prevented from later claiming invalidity only when that denial contradicts explicit or implicit promises made when they sold those rights.
- Bars inventors from attacking patents when they contradict promises made at the sale.
- Allows challenges if a buyer later broadens patent claims beyond what was assigned.
- Remands dispute to decide if Hologic’s claim is materially broader than assigned claims.
Summary
Background
Csaba Truckai invented a uterine ablation device and assigned his patent application to his company, which later sold the patent rights to Hologic. Truckai then founded Minerva and developed a different device. Hologic filed a continuation application and added a broader claim covering applicator heads regardless of moisture permeability. The PTO issued the altered patent, Hologic sued Minerva for infringement, and Minerva argued the new claim was invalid because the patent’s written description had addressed only moisture‑permeable heads.
Reasoning
The Court considered whether to abolish or narrow the doctrine called assignor estoppel, a rule that can bar an inventor who sold patent rights from later saying the patent is invalid. The majority held the rule survives but only where the inventor’s later invalidity claim contradicts explicit or implicit representations made when selling the patent. If an assignee later makes claims that are materially broader than the claims the inventor actually assigned, the inventor did not warrant those broader claims and may challenge them. The Court vacated the Federal Circuit’s judgment and remanded for a factual decision on whether Hologic’s new claim is materially broader than the assigned claims.
Real world impact
The ruling affects inventors, companies that buy patent rights, and firms sued for infringement. Inventors who truly promised the validity of specific claims can be precluded from attacking those claims. But inventors may be allowed to challenge newly added, materially broader claims. The remand means the case’s final result could change after the Federal Circuit applies the Court’s narrower rule.
Dissents or concurrances
Two Justices (Alito and Barrett, joined by others) dissented, arguing either that Westinghouse should be overruled or that the 1952 Patent Act does not support assignor estoppel; they urged different statutory and stare‑decisis analyses.
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