In Oil-Dri Corp. of Am. v. Nestlé Purina Petcare Co., Judge Kennelly of the Northern District of Illinois denied Plaintiff's motion for summary judgment on Defendant's obviousness defense, holding that inter partes review (IPR) estoppel did not preclude Defendant from raising a prior art patent in combination with evidence describing a prior art product.

Plaintiff Oil-Dri moved for summary judgment that Defendant Nestlé Purina should be estopped from raising the Shinohara patent in the district court because it could have reasonably raised it in the related IPR proceeding. In fact, the judge previously assigned to the case, Judge St. Eve, had ruled that Nestlé Purina was estopped from raising an anticipation defense based on the Shinohara patent. 

Nestlé Purina argued that the earlier ruling on anticipation does not extend to an obviousness defense for several reasons. First, the obviousness combination—which is based not only on the Shinohara patent, but also on additional evidence describing a prior art product—is different ground than the precluded anticipation ground. Second, Nestlé Purina could not have asserted the obviousness combination at the Patent Trial and Appeal Board (PTAB) because the scope of an IPR is limited to "patents or printed publications" and does not extend to other types of evidence related to a prior-art product. 

Upon consideration of the parties' respective positions, the court denied Oil-Dri's motion for summary judgment. In doing so, the court determined that Oil-Dri did not carry its burden of showing that estoppel was appropriate because it did not present evidence sufficient to show that printed materials describing the prior-art product qualified as "printed publications." According to the court, if such printed materials qualified as "printed publications," Nestlé Purina could have presented the obviousness combination to the PTAB and it would have been precluded  in district court.

Practice Tip: Where there is evidence that a petitioner had reasonable access to printed materials corresponding to, or describing, a product that it could have proffered during the IPR process, a party cannot avoid estoppel simply by pointing to its finished product (rather than the printed materials) during litigation. However, a patent owner asserting estoppel under 35 U.S.C. § 315(e) in district court must present evidence showing that any printed materials relied upon by an accused infringer were available upon a reasonable search. 

Oil-Dri Corp. of Am. v. Nestlé Purina Petcare Co., No. 15 C 1067 (N.D. Ill. Feb. 22, 2019)

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