Inherency: Same Enzyme => Same Enzymatic Activity

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.

= = = = =

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.”

14 thoughts on “Inherency: Same Enzyme => Same Enzymatic Activity

  1. 1

    This is an incredibly common fact pattern in the zymurgy arts: (1) inventor creates a new enzyme; (2) inventor patents new enzyme; (3) five (or seven, or ten, etc) years later, inventor discovers that patented enzyme has (e.g.) 30% better processivity (or RT shelf life, or HT stability, etc) than the closest prior art antecedent; (4) inventor says to patent attorney “I have these great new data, can we get a patent?”.

    The right answer is “no.” Your great data simply establish a previously unappreciated property of your already-patented enzyme. Reciting “wherein the enzyme has 30% higher processivity than ApoE” does not establish patentable novelty because this property is inherently present in the enzyme already described in the already granted patent.

    Regrettably, it can be very difficult to make inventors (i.e. clients) understand this. Moreover, the attorney’s pecuniary incentives do not encourage the effort to dissuade the inventor.

    And that is how claims like this one ends up getting filed…

    1. 1.1

      Just to be clear, when I say claims “like these,” that is what I mean—like these. I have no idea whether these claims emerged from such an uninspiring fact pattern.

    2. 1.2


      The other fact pattern that turns up is where a new method of purifying an old protein is developed and the resultant protein is somehow believed to be “better” than the identical protein in the prior art. You still can’t re-patent the protein by itself as a composition just by reciting the amino acid sequence and some non-structural property that wasn’t described in the prior art. You need to do the comparison directly. The strongest composition claim will require comparing that newly isolated protein with the same protein isolated by the prior art method and reciting the distinguishing structural features that are identified (e.g., a composition comprising the protein wherein some percent of the protein has a particular desirable conformation). Next “best” (but far from best) is measuring some readily and objectively determinable property (e.g., activity/mass) that is uniquely (relative to the prior art) tied to the structure of protein compositions which purified according to the new method. Again, direct comparison to the prior art is critical for avoiding these inherency issues and this latter type of claim is very prone to go up in flames if a distinct purification approach is shown by a competitor to yield the same result and there are no distinguishing structural features in the claim.

      1. 1.2.1

        Not quite accurate.

        For a number of reasons, but including your old stand-by attempt to make an optional claim format somehow not be optional.

        Do you remember a recent case in which the processing method alone in the claim provided enough distinction?

        Further, while the emphasis here is on “re-patenting” of the object physical item itself, Greg’s answer most likely needs to be amended to at least include discussions of potential new uses of old matter (vis a vis 35 USC 100(b) — “…and includes a new use of a known process, machine, manufacture, composition of matter, or material.”


          Do you remember a recent case in which the processing method alone in the claim provided enough distinction?

          Tell everyone what case you’re referring to, describe the claim, the relevant facts, and the holding. Go ahead, Billy. Become an adult for five minutes, today!

          Greg’s answer most likely needs to be amended to at least include discussions of potential new uses of old matter

          LOL Because why? Nothing he said suggests that you can’t patent a new method of using an old composition (assuming the method is useful, eligible and non-obvious, of course).


            Because his answer was entirely to the negative, while the potential at least of the positive that I supplied was omitted.

            That’s not a difficult concept for most people to grasp.

            As to the case, the moment you go to the levels (and engage on counterpoints presented to you at that level), I would be happy to oblige.

            That obliging, by the way, would have nothing to do with “being an adult,” so — yet again — your ad hominem is misaimed.

    3. 1.3

      I do not entirely agree with you. You need to investigate whether you can apply for a patent on a process that uses this newly discovered property of the enzyme.

      1. 1.3.1

        You need to investigate whether you can apply for a patent on a process that uses this newly discovered property of the enzyme.

        Naturally, I agree with you that before you tell the client “no, these data cannot support a new patent filing,” you need to consider a method of use claim. On the hypo above, however, it should still take you no more than ~5 min. reflection to see that there is no method claim here to pursue.

        N.B., the advantage shown in the hypothetical data is 30% increased processivity. Processivity is a property of the enzyme that one observes in the course of using the enzyme.

        To the extent that the original patent on the enzyme is properly enabled, that patent must have taught how to make and use the enzyme. The fact that this enzyme will—when used—function with a 30% greater processivity is inherent in the (by now prior art) disclosure of the enzyme’s use. In other words, even if you claim “a method of achieving 30% more processivity than ApoE, the method comprising incubating EdoP with a substrate at 37°C,” this is still inherently anticipated.

        The improved shelf stability alternative I mentioned above might support a claim to the effect of “a method of converting X to Y, the method comprising: (a) storing EdoP at a temperature between 5°C and 25°C for three weeks; and (b) incubating the EdoP with the X for 30 min. at about 37°C.” I would—absence specific business intelligence—discourage the client from pouring resources into pursuing this claim, because infringement would be so hard to detect that it would appear unlikely ever to prove a return on the capital invested to obtain the patent.

        At least that shelf stability claim could, however, plausibily survive an anticipation challenge. The improved processivity claim is just a loser ab initio.

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