by Dennis Crouch

In re Ikeda Food Research Co., Ltd. (Fed. Cir. 2019)

Ikeda is attempting to patent a glucose sensor using a particular enzyme (“a soluble flavin compound-binding glucose dehydrogenase”) that promotes glucose oxidizing. U.S. Application No. 12/851,668. One U.S. patent is already issued in the family as well as Japanese , Chinese, and European patents. In this case, however, the examiner rejected the claims as obvious and the PTAB affirmed. The Federal Circuit has now also affirmed that finding.

The case is most interesting for its inherency finding. Here, the claims at issue particularly require low-maltose activity (“enzymatic activity to maltose in the enzymatic reaction layer is 5% or less relative to the enzymatic activity to glucose.”) The prior art did not expressly teach that limitation, but the PTAB found it inherently disclosed. In particular, the cited prior art used the same enzyme preparation as the patentee, and the PTAB concluded that it would inherently exhibit the same low-level maltose activity.

Teachings that are inherent to a disclosure work as prior art — both for anticipation and obviousness. However, the court applies fairly strict requirements before it will assume the existence of unstated elements. “[T]he limitation at issue necessarily must be present[] or the natural result of the combination of elements explicitly disclosed by the prior art.” PAR Pharm., Inc. v. TWI Pharm., Inc., 773 F.3d 1186 (Fed. Cir. 2014).

In reviewing the evidence, the Federal Circuit found that the PTAB had reasonably concluded that when the enzyme was used in the prior art that it had the identical activity as claimed by Ikeda. In particular, the PTO properly made a prima facie case of inherency that was not sufficiently rebutted by the patent applicant.

The one good argument Ikeda made here involved a separate reference (Tsuji) that also used the identical enzyme and ended up with high-maltose activity. The courts, however, distinguished Tsuji because there was evidence of sample contamination in that case and no evidence that other non-related samples were contaminated.

The approach here follows Southwire Co. v. Cerro Wire LLC, 870 F.3d 1306 (Fed. Cir. 2017), where the court found it reasonable to assume that functional limitations were met if all of the other process limitations are met. “[T]here is no indication that

the limitation is anything other than mere quantification of the results of a known process.” Id.

In the absence of any evidence that the claimed [low activity] would have been unexpected in light of [Senior’s] disclosure, there is no indication that the limitation is anything other than mere quantification of the results of a known process.

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One unusual aspect of this case is that the parties are not fully named. Although Ikeda is apparently title owner, there is a second unnamed party that is “the Real Party in interest.” In its certificate of interest, Ikeda explains that it “shares a confidential business relationship with this entity.” Judge O’Malley granted Ikeda’s unopposed motion to keep this info secret.

Before the PTAB, Ikeda apparently did not reveal the darkhorse real-party in interest. In its decision, the PTAB explains “According to Appellants, the real party in interest is Ikeda Food Research Co. Ltd.”