In what appears to be the first district court case to address the issue directly, Judge Lefkow of the United States District Court for the Northern District of Illinois held that 35 U.S.C. § 315(e)(2) estoppel does not preclude parties from raising grounds in a civil litigation that were cumulative of grounds that could have been asserted during that party’s prior IPR proceeding, so long as the grounds are based on prior art that was not reasonably available during the IPR. 

On April 5, 2012, Clearlamp, LLC (“Clearlamp”) sued LKQ Corporation (“LKQ”) alleging patent infringement of U.S. Patent Number 7,297,364, entitled “Method for refurbishing lamp surfaces,” filed on December 19, 2005, and issued on November 20, 2007. Clearlamp, LLC v. LKQ Corp., Case No. 1:12-cv-02533 (N.D. Ill.).  LKQ answered and counterclaimed seeking declaratory judgments of non-infringement and invalidity.  The parties then participated in an inter partes review before the PTAB, which resulted in the PTAB canceling some, but not all, of the challenged claims.  After the IPR, the district court litigation continued with respect to the claims that survived the IPR, and the parties submitted cross-motions for summary judgment on invalidity and infringement/non-infringement.

LQK successfully moved the court to issue summary judgment that claims surviving the IPR were unpatentable as obvious based on a “datasheet” (for product UVHC3000) in combination with three prior art references the PTAB considered. Neither the datasheet nor the product described in the datasheet were presented to the PTAB for its consideration during the IPR.

Clearlamp argued that § 315(e)(2) estops LKQ from relying on the datasheet (and product described therein) in the civil litigation because either (1) LKQ reasonably could have raised invalidity grounds based on the product during the IPR or (2) LKQ reasonably could have raised grounds based on prior art cumulative to the product during the IPR.  Section 315(e)(2) states:

The petitioner in an inter partes review of a claim in a patent under this chapter that results in a final written decision under section 318(a), or the real party in interest or privy of the petitioner, may not assert either in a civil action arising in whole or in part under section 1338 of title 28 or in a proceeding before the International Trade Commission under section 337 of the Tariff Act of 1930 that the claim is invalid on any ground that the petitioner raised or reasonably could have raised during that inter partes review. (emphasis added)

As a matter of first impression, the court needed to interpret what “reasonably could have raised” means in the context of this statute.  As the court noted, “section 315(e)(2) estoppel is fairly new and the Federal Circuit has yet to define its scope.”  (Slip Op. 14).  Likewise, other district court cases addressing § 315(e)(2) “provide little insight into its breadth,” mainly because the courts that have addressed this section did so almost exclusively in the context of a motion to stay.  (Slip Op. 14).  Accordingly, the court turned to the statute’s legislative history, and specifically the Senate floor debate, to interpret the meaning of “reasonably” as used in the statute.  The court noted that Senator Kyl was “on point” when he said “adding the modifier ‘reasonably’ ensures that could-have-raised estoppel extends only to that prior art which a skilled searcher conducting a diligent search reasonably could have expected to discover.”  (Slip Op. 14).  Thus, “an inter partes review petitioner is estopped from relying on any ground that could have been raised based on prior art that could have been found by a skilled searcher’s diligent search.” (Slip Op. 15).

an inter partes review petitioner is estopped from relying on any ground that could have been raised based on prior art that could have been found by a skilled searcher’s diligent search.

Applied to this litigation, Clearlamp contended that estoppel applies because LKQ was aware of the product before it filed the IPR petition.  The Court rejected Clearlamp’s argument because a product is not the type of prior art that can form the basis of a prior art attack in an IPR.  (Slip Op. 17).  The court also scolded LKQ and rejected its attempt to “cloak its reliance upon [the] product so as to avoid § 315(e)(2) estoppel” because “it is the [product’s] datasheet upon which LKQ relies to invalidate the asserted claims.”  (Slip Op. 17).

The datasheet is a publication and, thus, it is the type of prior art that could have been used during the IPR.  Under § 315(e)(2), the datasheet can only be used in civil litigation if it could not have been found by a skilled researcher performing a diligent search.  The proponent of estoppel (here, Clearlamp) bears the burden of proof.  (Slip Op. 18).  Clearlamp failed to argue that a skilled searcher would have found the datasheet.  Instead, Clearlamp argued that a skilled searcher would have found prior art cumulative to the product, and because that cumulative prior art would have been admissible for the same argument for invalidity, LKQ should be estopped from using the datasheet (and product), even if it was not reasonably available during the IPR.  (Slip Op. 18-19).  Essentially, Clearlamp’s argument is that if there is any prior art that LKQ reasonably should have found and that prior art forms the basis for the same type of argument for invalidity, it doesn’t matter that this particular piece of art was not reasonably available, because LKQ had its opportunity to make the argument based on available prior art.

The court acknowledged that grounds can be cumulative or redundant of one another, but the court also said “that does not mean that § 315(e)(2) estops those grounds from being offered in civil litigation if they were not available during inter partes review.” (Slip Op. 16).   “The relevant inquiry, therefore, is not whether the ground is redundant of a ground that was asserted but, rather, whether the ground reasonably could have been raised.  Merely being redundant to a ground that could have been asserted during inter partes review does not estop the alleged infringer from relying upon a ground based upon prior art that was not reasonably available during inter partes review.”  (Slip. Op. 16-17).

The court rejected Clearlamp’s argument because “merely being cumulative of other prior art does not invoke § 315(e)(2) estoppel.” (Slip Op. at 19).  In addition, the court determined that Clearlamp failed to establish that the datasheet could have been found by a skilled searcher’s diligent search and thus the court held that the datasheet was not “reasonably available” during inter partes review such that LKQ would be precluded under section 315(e)(2) from asserting it in this civil litigation.

As perhaps an alternative basis for allowing the datasheet to be asserted in the civil litigation, at the end of the court’s section on estoppel, the court also commented “even if § 315(e)(2) estops cumulative pieces of prior art, it would not have that effect here where the datasheet discloses non-cumulative information.”

After determining that the datasheet was properly before the court as prior art for the purposes of invalidity in the civil litigation, the court performed a detailed obviousness analysis ultimately holding that the asserted claims were invalid as obvious. Thus, the court granted summary judgment of invalidity.