Law360 Quotes Rubén Muñoz on Estoppel Questions Among Patent Challengers

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Law360 has quoted Akin Gump intellectual property partner Rubén Muñoz in the article “The Estoppel Questions On The Minds Of Patent Challengers,” which looks at the issue of inter partes review (IPR) estoppel and whether it applies to physical products in district court.
The article notes that the Patent Trial and Appeal Board (PTAB), with its revised, all-or-nothing approach to patent reviews, has settled some debate over a rule that prevents invalidity arguments from being relitigated. This new approach, stemming from a 2018 Supreme Court decision, the article says, has somewhat simplified district courts’ analysis of the America Invents Act’s estoppel provision, thereby preventing challengers from arguing that a patent is invalid on grounds that were raised—or reasonably could have been raised—during IPR.
“[Review] became this binary decision, so in that sense it is simplified,” said Muñoz. “But there’s a lot more to estoppel that is not addressed by [the Supreme Court’s SAS Institute v. Iancu decision].”
When challenging a patent in IPR, the article says petitioners are limited to arguing that the patent is anticipated or obvious based on patents and printed publications, such as a textbook. Courts have also been asked to consider whether estoppel attaches to physical products that are described in a publication, but there is no consensus.
“I think the struggle for the courts is legitimate, in the sense that they don’t want parties to hide behind the cloak of invalidity based on a prior art product that is such only in name,” said Muñoz.
A similar question was addressed in federal court in California last month as to whether estoppel can attach to evidence intended to show that an invention was previously “known or used.”
The judge’s decision and the implication by the court, Muñoz observed, is that “estoppel would apply if the party asserting estoppel is able to show that material was publicly available to someone that could have used it in the IPR.”