On June 30, 2021,Chris Loh was quoted in Bio World on the Supreme Court’s decision in Minerva v. Hologic, a case that tested the boundaries of the doctrine of assignor estoppel, which bars a patent's seller (assignor) from attacking the patent's validity in subsequent patent infringement litigation.
According to the article, the parties to this lawsuit became locked in legal battle in 2015, when Hologic Inc. sued Minerva Surgical Inc. in a district court over patents initially held by Minerva, but which were transferred to a company that ultimately ended up as part of Hologic. Minerva subsequently filed for a patent for a related technology, thus setting off the chain of events that landed both parties at the Supreme Court. In an interesting disparity of venue, the Patent Trial and Appeal Board does not recognize assignor estoppel during IPR proceedings, while the U.S. International Trade Commission does.
The majority opinion in the June 29 decision by the Supreme Court reiterated the point that assignor estoppel is an informal doctrine grounded in “centuries-old fairness principles” and case law. However, the decision clarifies that assignor estoppel applies only when the assignor’s claim of invalidity of the assigned patent “contradicts explicit or implicit representations he made in assigning the patent.”
Loh told BioWorld that while this doctrine is still not observed during inter partes reviews (IPRs), the outcome may prod companies in the life sciences to spend more time jostling over contracts for patent assignment to tilt the question of estoppel in their favor.
Loh noted that the decision may generate “a fair amount of activity in terms of how assigners and assignees write their representations and warranties” pursuant to a transfer of a patent. Assignor estoppel does not function differently when a manufacturer purchases only a patent from another entity compared to when a patent is part of an acquisition of an entire company, but the Minerva decision “will spur transactional attorneys to look more closely at what specific representations or warranties accompany” the transaction, he said. Attorneys for each side in these contracts may thus seek to draft a contract with an eye to narrowing or expanding the potential for future assignor estoppel, as suits their interests.
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