District Court Limits Expansion Of IPR Estoppel Law
On July 21, 2021, the United States District Court for the Eastern District of Texas, Marshall Division, denied plaintiff’s motion for summary judgement that its patent was not invalid due to inter partes review (“IPR”) estoppel pursuant to 35 U.S.C. § 315(e)(2). General Access Solutions, Ltd. v. Sprint Spectrum LLC, 2-20-cv-00007 (Robert W. Schroeder, III).
Under Section 315(e)(2) of the patent statute, when a party seeks an IPR of a claim in a patent and the IPR results in a final written decision, the party “may not assert  in a civil action … that the claim is invalid on any ground that the petitioner raised or reasonably could have raised during that” IPR. 35 U.S.C. § 315(e)(2). An IPR petition, however, may only seek an IPR of a patent on the “basis of prior art consisting of patents or printed publications.” 35 U.S.C. § 311(b). Accordingly, prior art “systems” cannot be raised during IPR proceedings.
In July 2017, defendant Sprint Spectrum LLC (“Sprint”) initiated an IPR challenging the validity of a patent asserted in this district court litigation. Sprint raised three grounds challenging two independent claims, and two dependent claims. Sprint relied on a paper referred to as the Vornefeld paper. The PTAB issued a final written decision on March 7, 2019, invalidating the independent claims, but not the dependent claims.
In the district court case, following the final written decision, Sprint served supplemental invalidity contentions identifying the “Navini” system prior art, and argued that the dependent claims were obvious in view of the Navini system in combination with another prior art reference, Toshimitsu, that was not raised in the IPR.
Plaintiff General Access argued that the IPR estoppel applied to the combination of Navini and Toshimitsu on the basis that Navini was duplicative of the Vornefeld paper, and that Sprint could have raised the combination of Vornefeld and Toshimitsu in its IPR. Sprint argued that the key question in determining the scope of IPR estoppel is what constitutes a “ground” that was “raised or reasonably could have been raised” during an IPR. Further, because the Navini system prior art could not have been raised in the IPR (as it was not a printed publication), it could not be estopped from raising it in the district court.
The Court agreed with Sprint, finding that the Navini system prior art was completely separate and distinct from Vornefeld; for example, Vornefeld was not a publication that described Navini. The Court noted that “the logical conclusion of General Access’s argument would be that Sprint could not raise any systems art in this matter,” and refused to “endorse this expansion of estoppel law.”