No Estoppel In District Court On Prior Art That Differs Substantively—And In A Manner Germane To Invalidity—From That Asserted In IPR

Author:Mr Brooks J. Kenyon, Matthew G. Hartman and Rubén H. Muñoz
Profession:Akin Gump Strauss Hauer & Feld LLP

A Central District of California judge has clarified his prior ruling on summary judgment that estoppel under 35 U.S.C. § 315(e)(2) that applies to certain obviousness invalidity grounds raised by Defendants. In the prior ruling, the court found that Defendants could not side-step estoppel by characterizing a reference previously used in an inter partes review (IPR) as prior art that was “known or used by others” pursuant to pre-AIA § 102(a)—i.e., an invalidity ground not subject to estoppel. In doing so, the court estopped Defendants from raising all but one obviousness invalidity ground.

On Defendants' motion for reconsideration, the court clarified its prior ruling. As an initial matter, the court noted that the parties disagreed on how to distinguish invalidity grounds that could have been raised in an IPR petition with those not subject to IPR estoppel. The Federal Circuit, as the Court explained, has not addressed this dispute, nor have district courts dealt with the specific question at issue: whether IPR estoppel can preclude a patent challenger from relying on a “known or used” invalidity ground that is related to the printed publications that were asserted before the Patent Trial and Appeal Board (PTAB). The court, nevertheless, considered how other district courts have determined when estoppel should apply to prior art products and systems.

In one instance, the Central District of California declined to extend estoppel to a physical machine when the machine disclosed features not included in the printed publication. Star Envirotech, Inc. v. Redline Detection, LLC, No. 8:12-cv-01861 (C.D. Cal. Jan. 29, 2015). That court considered the machine asuperior and separate reference. In another instance, the Northern District of Illinois found thatthe relevant inquiry [was] not whether the ground is redundant of a ground that was asserted but, rather, whether the ground reasonably could...

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