Under 35 U.S.C. § 311(b), “[a] petitioner in an inter partes review may request to cancel as unpatentable 1 or more claims of a patent only on a ground that could be raised under section 102 or 103 and only on the basis of prior art consisting of patents or printed publications.”  In Intri–Plex Technologies, Inc. and Mmi Holdings, Ltd., v. Saint–Gobain Performance Plastics Rencol Limited, IPR2014–00309 (Paper 83), the Board denied Saint-Gobain’s challenge to the use of Applicant’s Admitted Prior Art under Section 311(b) even though the admission was not necessarily a patent or printed publication under the express definition of the statute. 

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In Intri-Plex, Petitioner filed an inter partes review of U.S. Patent No. 8,228,640 (“the ‘640 patent”). The ‘640 patent relates to hard disc drives, and claim 1 specifically recites a tolerance ring with a funnel-shaped guide portion (depicted in FIG. 4 of the ‘640 patent as guide portion 14).

The Board instituted inter partes review of claims 1-10 of the ‘640 patent as allegedly being obvious in view of Admitted Prior Art (i.e. FIGs. 1, 2, and 3 of the ‘640 patent) and U.S. Patent No. 2,931,412 to Wing.  Petitioner’s argued that the Admitted Prior Art disclosed all the features of claim 1 besides the funnel-shaped guide portion.  A cursory comparison of FIG. 2 with FIG. 4 appears to support Petitioner’s argument.

As a counter argument, Saint-Gobain argued that the Admitted Prior Art, specifically FIG. 2 of the Admitted Prior Art was outside the scope of prior art because (1) the Admitted Prior Art was not a patent or printed publication as required under § 311(b) and (2) any admissions of the prior art were a mistake and should be recanted.

Rebutting Saint Gobain’s arguments that the Admitted Prior Art was not a patent or printed publication, the Board first acknowledged that these arguments were a case of first impression, and therefore, the Board provided detailed reasoning for its analysis.  Specifically, the Board reasoned (a) admissions within the four-corners of a challenged patent may be “prior art consisting of patents” under the statute, (b) while § 311(b) was intended to limit the scope of IPR challenges, its intention was not to exclude prior art traditionally considered prior art by the Patent Office, and (c) even if the Admitted Prior Art is not prior art under § 311(b) per se, such admissions constitute background knowledge which may be used as evidence under the Graham factors of obviousness.

The Board noted that patent application admissions have long been treated as prior art even if they are “not expressly listed as prior art under the statute.” Further, the Board stated that “[t]he fact that Saint-Gobain made admissions against its own interest in the public record within the four corners of its own patent is reliable evidence that the admitted prior art antedates the claimed invention.” Thus, the Board held that Applicant’s Admitted Prior Art falls within the scope of § 311(b).

Similarly, the Board was not persuaded that Applicant’s admissions were a mistake, which should now be recanted.  In the ‘640 patent, FIGs. 1-3 were labeled as “Prior Art” and the description of these figures described “known” features.  In its arguments, the Saint-Gobain attempted to recant its admission that FIG. 2 was admitted prior art, because FIG. 2 actually illustrated the inventor’s own work.

The Board was not persuaded because the admissions were made on the face of the patent (i.e. drawings and specification). The Board distinguished the instant case from Riverwood Int’l Corp. v. R.A. Jones & Co., Inc., 324 F.3d 1346 (Fed. Cir. 2003), in which the Federal Circuit vacated a judgment of invalidity where invalidity was based on inventor’s own work which was included in an information disclosure statement. The Board noted that in Riverwood, the “Federal Circuit reasoned that a patentee should not be punished for being overly inclusive in referencing his own work in an IDS.”  In contrast to Riverwood, the Board referenced In re Nomiya, 509 F.2d 566, 571 n. 5 (CCPA 1975), which held that valid prior art may be created by admissions made during prosecution. Similarly, in Nomiya, the applicant labelled FIGs. 1 and 2 as prior art and the court determined that such labeling was a concession of “what is to be considered as prior art in determining obviousness of their improvement.”

Further, the Board made a policy argument and stated that a patent’s disclosure notifies the public of an invention and any admissions of prior art in the disclosure may be reasonably relied on by the public. The Board determined that a patent owner cannot reclaim subject matter which was already disclaimed and admitted as being prior art to the public. The Board opined: “We are not persuaded that Saint-Gobain should be permitted to change its position and assert now that its admission was a ‘mistake’ in order to gain an advantage over an adversary and competitor years after the patent has issued.”

As an aside, the Board also commented that even if the admissions regarding FIG. 2 were recanted, such actions would not be dispositive because Applicant’s Admitted Prior Art would still include FIGs. 1 and 3, and their related disclosures, which are very similar to FIG. 2.

Interestingly, even though the Board considered Applicant’s Admitted Prior Art and found that claims 1-10 would have been obvious in view of the admissions and Wing, the patent remained unscathed because of a strong showing of nonobviousness based on commercial success of the patented invention.

Nevertheless, given Intri-Plex, practitioners should carefully weigh the risks of making admissions during prosecution of patent applications because these admissions may be considered prior art in inter partes review proceedings even if such admissions are not expressly defined under § 311(b).