Ajinomoto Co., Inc. v. Itc , 932 F.3d 1342 ( 2019 )


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  •  United States Court of Appeals
    for the Federal Circuit
    ______________________
    AJINOMOTO CO., INC., AJINOMOTO HEARTLAND
    INC.,
    Appellants
    v.
    INTERNATIONAL TRADE COMMISSION,
    Appellee
    CJ CHEILJEDANG CORP., CJ AMERICA, INC., PT
    CHEILJEDANG INDONESIA,
    Intervenors
    --------------------------------------------
    CJ CHEILJEDANG CORP., CJ AMERICA, INC., PT
    CHEILJEDANG INDONESIA,
    Appellants
    v.
    INTERNATIONAL TRADE COMMISSION,
    Appellee
    AJINOMOTO CO., INC., AJINOMOTO HEARTLAND
    INC.,
    Intervenors
    ______________________
    2018-1590, 2018-1629
    ______________________
    2                                  AJINOMOTO CO., INC. v. ITC
    Appeals from the United States International Trade
    Commission in Investigation No. 337-TA-1005.
    ______________________
    Decided: August 6, 2019
    ______________________
    JOHN D. LIVINGSTONE, Finnegan, Henderson, Farabow,
    Garrett & Dunner, LLP, Atlanta, GA, argued for Ajinomoto
    Co., Inc., Ajinomoto Heartland Inc. Also represented by
    MARTIN DAVID WEINGARTEN; CHARLES E. LIPSEY, Reston,
    VA; MAREESA ARNITA FREDERICK, CORA RENAE HOLT,
    BARBARA RUDOLPH, Washington, DC.
    HOUDA MORAD, Office of General Counsel, United
    States International Trade Commission, Washington, DC,
    argued for appellee. Also represented by SIDNEY A.
    ROSENZWEIG, DOMINIC L. BIANCHI, WAYNE W. HERRINGTON.
    JAMES F. HALEY, JR., Haley Guiliano LLP, New York,
    NY, argued for CJ CheilJedang Corp., CJ America, Inc., PT
    CheiJedang Indonesia. Also represented by STEVEN PEPE,
    Ropes & Gray LLP, New York, NY; MATTHEW RIZZOLO,
    Washington, DC.
    ______________________
    Before DYK, MOORE, and TARANTO, Circuit Judges.
    Opinion for the court filed by Circuit Judge TARANTO.
    Opinion concurring in part and dissenting in part filed by
    Circuit Judge DYK.
    TARANTO, Circuit Judge.
    Ajinomoto Co., Inc. and Ajinomoto Heartland Inc. (col-
    lectively, Ajinomoto) filed a complaint against CJ
    CheilJedang Corp., CJ America, Inc., and PT CheilJedang
    Indonesia (collectively, CJ) with the International Trade
    Commission, alleging that CJ was importing certain
    AJINOMOTO CO., INC. v. ITC                                 3
    products that infringed Ajinomoto’s 
    U.S. Patent No. 7,666,655
    . CJ used several strains of Escherichia coli bac-
    teria to produce L-tryptophan products, which it then im-
    ported into the United States.           The Commission
    determined that CJ’s earlier strains did not infringe but
    that CJ’s two later strains did. The Commission also found
    that the relevant claim of the ’655 patent is not invalid for
    lack of an adequate written description.
    Ajinomoto appeals the Commission’s claim construc-
    tion underlying the determination of no infringement by
    the earlier strains. CJ cross-appeals aspects of the deter-
    mination of infringement by the later strains and the rejec-
    tion of the invalidity challenge. We affirm.
    I
    A
    The ’655 patent claims E. coli bacteria that have been
    genetically engineered to increase their production of aro-
    matic L-amino acids, such as L-tryptophan, during fermen-
    tation, as well as methods of producing aromatic L-amino
    acids using such bacteria. See ’655 patent, col. 2, lines 40–
    45. In particular, the ’655 patent identifies a specific gene
    in the E. coli genome, the yddG gene, that encodes a mem-
    brane protein, the YddG protein. 
    Id.,
     col. 2, lines 46–48.
    That protein transports aromatic L-amino acids out of the
    bacterial cell and into the surrounding culture medium,
    where they can be collected. See 
    id.,
     col. 7, lines 11–16.
    When yddG gene activity in bacteria is enhanced so that
    more YddG protein is produced, the bacteria show in-
    creased production of, and increased resistance to, aro-
    matic L-amino acids. 
    Id.,
     col. 2, lines 49–57. 1
    1  The specification defines a bacterium’s “resistance”
    to an amino acid as its ability “to grow on a minimal me-
    dium containing” the amino acid on “which unmodified or
    4                                     AJINOMOTO CO., INC. v. ITC
    The ’655 patent describes three ways to enhance the
    activity of the yddG gene. First, plasmids containing addi-
    tional copies of the yddG gene can be introduced into the
    bacterium. 
    Id.,
     col. 2, lines 50–52; 
    id.,
     col. 5, line 62,
    through col. 6, line 2. Second, additional copies of the yddG
    gene can be inserted into the bacterial chromosome. 
    Id.,
    col. 2, lines 52–54; 
    id.,
     col. 6, lines 3–6. Third, a stronger
    “promoter” than the one native to the E. coli yddG gene can
    be used. 
    Id.,
     col. 2, lines 54–57; 
    id.,
     col. 6, lines 12–15. 2
    Claim 20, the only claim of the ’655 patent still asserted
    when the Commission issued its decision, claims “[a]
    method for producing an aromatic L-amino acid, which
    comprises cultivating the bacterium according to any
    one of claims 9–12, 13, 14, 15–18, or 19.” 
    Id.,
     col. 24, lines
    the wild type, or the parental strain of the bacterium can-
    not grow,” or its ability “to grow faster” on such a medium
    “than unmodified or the wild type, or the parental strain of
    the bacterium.” ’655 patent, col. 4, lines 49–56.
    2   A promoter is a nucleotide sequence within a DNA
    molecule, located adjacent to the nucleotide sequence that
    constitutes the gene to be expressed. The Lewin textbook
    cited by Ajinomoto shows a “typical promoter” around 41
    nucleotides long. J.A. 6043; see also J.A. 6177 (article by
    Deuschle et al., cited at ’655 patent, col. 6, lines 18–21,
    showing longer promoters). The promoter is the binding
    site for RNA polymerase, which initiates transcription (the
    first step in gene expression) by separating the two strands
    of DNA. The ’655 patent’s specification defines “[s]trength
    of promoter” with reference to the “frequency of acts of the
    RNA synthesis initiation.” ’655 patent, col. 6, lines 15–16.
    The promoter is only one part of a gene’s “expression
    regulation sequence,” which controls expression of the
    gene. See 
    id.,
     col. 3, line 14; 
    id.,
     col. 5, line 2. Besides pro-
    moters, the “expression regulation sequence” can include,
    e.g., operators, enhancers, terminators, and silencers.
    AJINOMOTO CO., INC. v. ITC                                  5
    4–6 (emphasis added). Of the claims in that list, claims 9
    and 15 are the independent claims, and they are the two
    alternatives, under claim 20, of importance in this case.
    Claim 9 recites:
    9. A recombinant Escherichia coli bacterium,
    which has the ability to accumulate aromatic L-
    amino acid in a medium, wherein the aromatic L-
    amino acid production by said bacterium is en-
    hanced by enhancing activity of a protein in a cell
    of said bacterium beyond the levels observed in a
    wild-type of said bacterium,
    [1] and in which said protein consists of the
    amino acid sequence of SEQ ID NO: 2
    [2] and said protein has the activity to make
    the bacterium resistant to L-phenylalanine, fluoro-
    phenylalanine or 5[-]fluoro-DL-tryptophan,
    [3] wherein the activity of the protein is en-
    hanced by [3a] transformation of the bacterium
    with a DNA encoding the protein to express the
    protein in the bacterium, [3b] by replacing the na-
    tive promoter which precedes the DNA on the chro-
    mosome of the bacterium with a more potent
    promoter, [3c] or by introduction of multiple copies
    of the DNA encoding said protein into the chromo-
    some of said bacterium to express the protein in
    said bacterium.
    
    Id.,
     col. 22, lines 51–67 (paragraph breaks and bold num-
    bering added). The Commission referred to limitation [1]
    as the “protein limitation,” limitation [2] as the “resistance
    limitation,” and limitation [3] as the “enhancement limita-
    tion.” Claim 15 is materially identical to claim 9, except for
    the protein limitation. Whereas claim 9 identifies the
    claimed protein by a specific amino-acid sequence, claim 15
    identifies it by reference to a corresponding DNA se-
    quence—a protein “encoded by the nucleotide sequence
    6                                  AJINOMOTO CO., INC. v. ITC
    which hybridizes with the complement of the nucleotide se-
    quence of SEQ ID NO: 1 under” certain conditions. See 
    id.,
    col. 23, lines 14–32.
    B
    In May 2016, Ajinomoto filed a complaint against CJ
    with the Commission under 
    19 U.S.C. § 1337
    . Ajinomoto
    alleged that CJ violated § 1337(a)(1)(B)(ii) by importing an-
    imal-feed-grade L-tryptophan products produced by a pro-
    cess covered by the ’655 patent. 3 The Commission
    instituted an investigation based on Ajinomoto’s com-
    plaint.
    The parties before us, including the Commission, agree
    that whether the accused products were produced by a pro-
    cess covered by the patent is a question of infringement.
    The proceeding focused on three groups of E. coli strains
    that CJ has used to produce tryptophan. First, CJ’s “ear-
    lier strains” contained both the native E. coli yddG gene
    and the native E. coli yddG promoter, except that the first
    nucleotide of the promoter was changed through chemical
    mutagenesis, resulting in a stronger promoter. Second, in
    November 2016, several months after Ajinomoto filed its
    complaint, CJ began using its first “later strain,” which
    contained two copies of a yddG gene: (1) the native E. coli
    yddG gene with the native E. coli yddG promoter; and (2) a
    non-E. coli yddG gene with two promoters—(2a) a native
    non-E. coli yddG promoter and (2b) an rmf promoter. 4
    Third, in December 2016, CJ started using its second “later
    3   Ajinomoto also alleged that CJ infringed U.S. Pa-
    tent No. 6,180,373, which similarly claims methods of pro-
    ducing tryptophan using genetically engineered bacteria.
    The ’373 patent expired on January 30, 2018, and is not at
    issue in this court.
    4   The rmf and rhtB promoters are promoters associ-
    ated with other genes in the E. coli genome.
    AJINOMOTO CO., INC. v. ITC                                 7
    strain,” which also contained two copies of a yddG gene:
    (1) the native E. coli yddG gene with the native E. coli
    yddG promoter; and (2) a codon-randomized non-E. coli
    yddG gene with two promoters—(2a) an rmf promoter and
    (2b) an rhtB promoter. 5
    In August 2017, the administrative law judge (ALJ) is-
    sued a final initial determination. The ALJ construed “re-
    placing the native promoter . . . with a more potent
    promoter” in the enhancement limitation to mean “remov-
    ing the native upstream region of the yddG gene and in-
    serting one of a class of promoters that controls expression
    of a different gene.” J.A. 90–91. Using that construction,
    the ALJ found that CJ’s earlier strains did not infringe; he
    found that they failed to meet the enhancement limitation
    because CJ created the more potent promoter in those
    strains by mutagenesis of a single nucleotide rather than
    removal of the entire native promoter and insertion of a
    new promoter. As to CJ’s later strains, the ALJ found that
    (a) the first later strain did not infringe because Ajinomoto
    had failed to prove that it met the resistance limitation,
    and (b) the second later strain also did not infringe because
    5    Each particular codon (three nucleotides in a row
    on a DNA molecule) that encodes for an amino acid always
    encodes for the same amino acid, but many of the 20 amino
    acids are encoded by more than one of the 64 codons. See
    Amgen, Inc. v. Chugai Pharm. Co., 
    927 F.2d 1200
    , 1208 n.4
    (Fed. Cir. 1991) (discussing “redundancy” of genetic code).
    For instance, the DNA sequences TTA and TTG both code
    for the amino acid leucine. “Codon randomization” refers
    to creation of DNA molecules that use different codons (e.g.,
    TTA or TTG) to code for the same amino acid (e.g., leucine)
    in building the same protein. See Mycogen Plant Sci. v.
    Monsanto Co., 
    243 F.3d 1316
    , 1323 (Fed. Cir. 2001) (“[O]ne
    codon can be substituted for another in the gene without
    changing the amino acid and resulting protein.”).
    8                                  AJINOMOTO CO., INC. v. ITC
    its non-E. coli YddG protein was not equivalent to the
    claimed E. coli YddG protein under the doctrine of equiva-
    lents. Finally, the ALJ found that claim 20 of the ’655 pa-
    tent is invalid for lack of an adequate written description
    of the “more potent promoter” limitation incorporated into
    that claim.
    In October 2017, the full Commission decided to review
    the ALJ’s final initial determination in its entirety, and in
    December 2017, the Commission issued its decision. It af-
    firmed the ALJ’s construction of “replacing the native pro-
    moter . . . with a more potent promoter” and accordingly
    affirmed the ALJ’s finding that CJ’s earlier strains did not
    infringe. But the Commission reversed several of the ALJ’s
    other findings. Specifically, it determined that both of CJ’s
    later strains met all disputed claim limitations and thus
    infringed claim 20 and that claim 20 was not proved to lack
    an adequate written description. The Commission accord-
    ingly entered a limited exclusion order against CJ’s infring-
    ing products, i.e., those made by both of CJ’s later strains
    but not its earlier strains. The Commission also issued a
    cease-and-desist order against CJ America, which held in-
    ventory of the infringing products.
    Ajinomoto and CJ both timely appealed. We have ju-
    risdiction under 
    28 U.S.C. § 1295
    (a)(6).
    II
    We begin with Ajinomoto’s appeal of the Commission’s
    finding of no infringement by the earlier strains.
    Ajinomoto challenges that finding solely by arguing that
    the Commission erred in its claim construction of “replac-
    ing the native promoter . . . with a more potent promoter.”
    Ajinomoto argues that, properly construed, the phrase is
    not limited to removing the entire native promoter and in-
    serting a new promoter, as the Commission concluded, but
    encompasses mutagenesis of individual nucleotides within
    the native promoter. We review the Commission’s claim
    construction de novo, as the Commission relied on only
    AJINOMOTO CO., INC. v. ITC                                   9
    intrinsic evidence and made no factual findings based on
    extrinsic evidence. Teva Pharm. USA, Inc. v. Sandoz, Inc.,
    
    135 S. Ct. 831
    , 841 (2015); see Cont’l Circuits LLC v. Intel
    Corp., 
    915 F.3d 788
    , 795 (Fed. Cir. 2019). We agree with
    the Commission’s claim construction and therefore affirm
    the non-infringement finding.
    The ordinary and customary meaning of the claim lan-
    guage provides support for the Commission’s claim con-
    struction. The language of “replacing the native promoter
    . . . with a more potent promoter” suggests, in ordinary par-
    lance, an operation at the level of the entire promoter as a
    unit, not at the level of a single nucleotide that is just one
    small component of the promoter. To say that one is “re-
    placing” an object (e.g., a laptop computer, a bicycle, a sail-
    boat, a blender) suggests that one is doing more than
    altering one small part of it. That suggestion is bolstered
    when one also uses language (here, a “more potent pro-
    moter”) referring to the replacement at the level of the
    overall object. The suggestion is further reinforced by the
    most apt of the dictionary definitions of “replace” intro-
    duced before the Commission—“to provide a substitute
    for.” J.A. 10361; see also J.A. 5622 (patent applicants ex-
    plaining “replacing” as “substitut[ing]”). In many contexts,
    one would not refer to swapping out one small component
    of a larger unit as “replacing” the unit or as providing a
    “substitute” for the unit, even though the net result is a
    differently constituted larger unit. Context matters, of
    course, but here, Ajinomoto has not shown a contrary com-
    mon understanding (or even one of several common under-
    standings) among relevant artisans in the specific context
    of replacing a promoter with a more potent promoter. Ac-
    cordingly, the claim language, though hardly establishing
    a plain meaning, supports the Commission’s construction.
    The specification offers additional support, though it
    too is hardly plain insofar as it bears on the particular con-
    struction issue. The specification states that “the enhance-
    ment of gene expression can be achieved by locating the
    10                                    AJINOMOTO CO., INC. v. ITC
    DNA of the present invention under control of more potent
    promoter instead of the native promoter.” ’655 patent,
    col. 6, lines 12–15. That statement speaks of a promoter as
    a unit, but it does not use the language of “replacing.” In-
    deed, the specification nowhere uses that language. But it
    does discuss “substituting” promoters, using a term that,
    as indicated above, is an apt definition of “replacing” here.
    The specification describes “[t]he present inventions” as in-
    cluding “[t]he bacterium according to the above bacterium,
    wherein native promoter of said DNA is substituted with
    more potent promoter.” 
    Id.,
     col. 3, lines 19–21. The term
    is then used in Example 4, which is titled “Substitution of
    the Native Upstream Region of yddG Gene by the Hybrid
    Regulatory Element Carrying the PL Promoter and SDlacZ
    in E. coli Chromosome,” and which involves removing the
    entire native promoter and inserting a new promoter. See
    
    id.,
     col. 11, line 5, through col. 12, line 46. The sole specifi-
    cation example of “substitution” thus fits the Commission’s
    claim construction. And while the specification discusses
    mutagenesis, it does so only in the context of the protein-
    coding region of the yddG gene, not the promoter. See 
    id.,
    col. 5, lines 18–30.
    We turn finally to the prosecution history—on which
    the parties to this case have focused most of their compet-
    ing analyses. We conclude that the best understanding of
    what transpired before the examiner further supports the
    Commission’s construction. Because the prosecution his-
    tory reinforces what is already suggested by the claim lan-
    guage and specification, this case provides no occasion,
    contrary to Ajinomoto’s contention (Ajinomoto Br. 34), for
    requiring clear and unmistakable disavowal or disclaimer
    to justify a claim construction contrary to a meaning evi-
    dent from the claim language and specification.
    What was claim 2 of the original application recited
    “[t]he bacterium according to claim 1, wherein said activi-
    ties of proteins . . . is enhanced by transformation of said
    bacterium with DNA coding for the protein . . . or by
    AJINOMOTO CO., INC. v. ITC                                  11
    alteration of expression regulation sequence of said DNA on
    the chromosome of the bacterium.” J.A. 5047 (emphasis
    added). 6 The examiner rejected the claim for lack of an ad-
    equate written description and lack of enablement. As to
    written description, the examiner explained that “[w]hile
    generic expression regulation sequences are known in the
    art, a particular, endogenous expression regulation se-
    quence for the DNA that encodes [amino-acid] SEQ ID
    NO:2, or related sequences, is not described.” J.A. 5371.
    “Without description of the endogenous regulation se-
    quence,” the examiner continued, “an endogenous regula-
    tion sequence that has been altered to increase expression
    of said protein also lacks adequate written description.” 
    Id.
    Turning to enablement, the examiner stated:
    The specification, while being enabling for Esche-
    richia strains wherein the native promoter for the
    DNA encoding SEQ ID NO: 2 has been changed by
    substitution with a more potent promoter, does not
    reasonably provide enablement for the genus of an
    L-amino acid producing bacterium wherein the ac-
    tivity of proteins described by SEQ ID NO: 2 and
    related sequences is increased due to specific alter-
    ations within the chromosomal expression regula-
    tion sequence for DNA encoding said proteins.
    ....
    6   Although claims 9 and 15 issued from what were
    numbered as claims 12 and 24 when added during prose-
    cution, the parties do not dispute that the amendments to
    original claim 2 (which eventually was cancelled) are rele-
    vant to construing issued claims 9 and 15. The same “re-
    placing the native promoter . . . with a more potent
    promoter” language added to original claim 2 was eventu-
    ally added to claims 9 and 15.
    12                                  AJINOMOTO CO., INC. v. ITC
    The instant specification teaches how to select
    Escherichia bacteria that have an increased pro-
    duction of L-amino acids, and the art teaches how
    to mutagenize chromosomal DNA and how to char-
    acterize the mutations in the DNA. However, nei-
    ther the specification nor the art contain any
    examples of how to specifically change endogenous
    Escherichia chromosomal expression regulation se-
    quences for the DNA encoding proteins described
    by SEQ ID NO: 2, or related sequences, such that
    the activity of said proteins in the bacteria is in-
    creased. The art and the specification provide en-
    ablement for inserting a known promoter in the
    chromosomal DNA to upregulate the expression of
    the DNA encoding SEQ ID NO: 2; however, neither
    the specification nor the art enable making specific
    changes to expression regulation sequences for
    DNA encoding SEQ ID NO:2 and related sequences
    on the chromosome of Escherichia bacteria. The
    art and specification lack a detailed description of
    the structure of the instant endogenous expression
    regulation sequences, and they lack any guidance
    on how to alter such sequences such that DNA ex-
    pression is increased; therefore, to make the in-
    stant bacteria with altered expression regulation
    sequences would be unpredictable.
    J.A. 5374–75.
    In response to the rejections, the applicants amended
    the claim to recite “replacing the native promoter that pre-
    cedes a DNA encoding said protein . . . with a more potent
    promoter” instead of “by alteration of expression regulation
    sequence of said DNA.” J.A. 5610. The applicants ex-
    plained the amendment as follows: “Applicants have
    amended Claim 2 consistent with the Examiner’s recogni-
    tion that the specification enables Escherichia strains
    wherein the native promoter for the DNA encoding SEQ ID
    AJINOMOTO CO., INC. v. ITC                                  13
    NO: 2 has been changed by substitution with a more potent
    promoter.” J.A. 5622.
    Reading the written-description and enablement rejec-
    tions together, we think that the most reasonable under-
    standing of the examiner’s comments is that the examiner
    was drawing a distinction between alterations to the pro-
    moter, which were sufficiently described and enabled be-
    cause E. coli promoters were well understood in the art,
    and alterations to the expression-regulation sequence more
    broadly, which were not adequately described or enabled.
    To be sure, the examiner’s statement that the art and the
    specification “lack any guidance on how to alter such se-
    quences such that DNA expression is increased” might at
    first suggest that the applicants had not described and en-
    abled the full scope of “alteration.” But in context, this
    statement is best read as meaning that the applicants had
    not described and enabled the full scope of “expression reg-
    ulation sequence,” so that “alteration” of that sequence also
    was not adequately described or enabled, even though gen-
    eral techniques for altering DNA sequences were well
    known in the relevant art.
    We need not determine the precise basis for the exam-
    iner’s rejections, however, as “there is no principle of patent
    law that the scope of a surrender of subject matter during
    prosecution is limited to what is absolutely necessary to
    avoid a prior art reference that was the basis for an exam-
    iner's rejection.” Norian Corp. v. Stryker Corp., 
    432 F.3d 1356
    , 1361 (Fed. Cir. 2005). Rather, patentees frequently
    “surrender more through amendment than may have been
    absolutely necessary to avoid particular prior art.” 
    Id.
    That principle logically extends to amendments made to
    overcome rejections under § 112. Cf. Biogen Idec, Inc. v.
    GlaxoSmithKline LLC, 
    713 F.3d 1090
    , 1095–96 (Fed. Cir.
    2013). Indeed, we have stated more generally that “[t]he
    question is what a person of ordinary skill would under-
    stand the patentee to have disclaimed during prosecution,
    not what a person of ordinary skill would think the
    14                                 AJINOMOTO CO., INC. v. ITC
    patentee needed to disclaim during prosecution.” Tech.
    Props. Ltd. LLC v. Huawei Techs. Co., 
    849 F.3d 1349
    , 1359
    (Fed. Cir. 2017). A patentee must “be held to what he de-
    clares during the prosecution of his patent,” because a con-
    trary rule would undermine “[t]he public notice function of
    a patent.” Springs Window Fashions LP v. Novo Indus.,
    L.P., 
    323 F.3d 989
    , 995 (Fed. Cir. 2003).
    We conclude that this is a case where the applicants
    surrendered more than may have been necessary. As dis-
    cussed above, the best reading of the prosecution history is
    that, to overcome the written-description and enablement
    rejections, it might well have sufficed if the applicants had
    narrowed their claims from alterations to the overall ex-
    pression-regulation sequence to alterations to the pro-
    moter.     But the applicants did not merely change
    “expression regulation sequence” to “native promoter”;
    they also changed “alteration” to “replacing.” Just as
    “when different words are used in separate claims, they are
    presumed to have different meanings,” Aspex Eyewear, Inc.
    v. Marchon Eyewear, Inc., 
    672 F.3d 1335
    , 1349 (Fed. Cir.
    2012), when a word is changed during prosecution, the
    change tends to suggest that the new word differs in mean-
    ing in some way from the original word.
    That inference is bolstered by the applicants’ remarks
    accompanying the amendment. Those remarks effectively
    equate “replacing the native promoter . . . with a more po-
    tent promoter” in the amended claim with “chang[ing]” the
    native promoter “by substitution with a more potent pro-
    moter.” J.A. 5622. As we have already noted, Example 4,
    described as involving “substitution” of a promoter, in-
    volves removal of the entire native promoter and insertion
    of a new promoter. ’665 patent, col. 11, line 5, through col.
    12, line 46. The applicants’ remarks, understood in light of
    the word choices and the specification, thus reinforce the
    Commission’s conclusion that the new claim language does
    not include mutagenesis of individual nucleotides.
    AJINOMOTO CO., INC. v. ITC                                 15
    For those reasons, we affirm the Commission’s claim
    construction and its finding that CJ’s earlier strains do not
    infringe based on that claim construction.
    III
    CJ, in its cross-appeal, challenges the Commission’s
    determinations that CJ’s second later strain met the pro-
    tein limitation, that both of CJ’s later strains met the re-
    sistance limitation, and that claim 20 is not invalid for lack
    of an adequate written description. We affirm the Commis-
    sion as to all three issues.
    A determination of infringement or non-infringement,
    whether literal or under the doctrine of equivalents, is a
    finding of fact, reviewed here for substantial evidence.
    Kinik Co. v. Int’l Trade Comm’n, 
    362 F.3d 1359
    , 1361 (Fed.
    Cir. 2004). But a determination of the applicability or in-
    applicability of prosecution history estoppel, which limits
    the availability of the doctrine of equivalents, is a matter
    of law, reviewed de novo. Spectrum Pharm., Inc. v. Sandoz
    Inc., 
    802 F.3d 1326
    , 1337 (Fed. Cir. 2015). The determina-
    tion that a patent claim did not lack adequate support in
    the written description is a factual finding, reviewed for
    substantial evidence. Rivera v. Int’l Trade Comm’n, 
    857 F.3d 1315
    , 1319 (Fed. Cir. 2017). Ajinomoto had to prove
    infringement by a preponderance of the evidence, while CJ
    had to prove invalidity by clear and convincing evidence.
    See Motorola Mobility, LLC v. Int’l Trade Comm’n, 
    737 F.3d 1345
    , 1348 (Fed. Cir. 2013); Enercon GmbH v. Int’l
    Trade Comm’n, 
    151 F.3d 1376
    , 1384 (Fed. Cir. 1998).
    A
    The Commission found that CJ’s second later strain in-
    fringed claim 20, which covers two alternatives of rele-
    vance in this case—the claim 9 alternative and the claim
    15 alternative. The infringement finding for CJ’s second
    later strain does not rest on the claim 15 alternative,
    which, in its protein limitation, requires a protein encoded
    16                                 AJINOMOTO CO., INC. v. ITC
    by a nucleotide sequence that hybridizes with the comple-
    ment of SEQ ID NO:1 (the nucleotide sequence of the E.
    coli yddG gene). The Commission did not find, and
    Ajinomoto does not argue for, either literal or equivalents
    infringement based on claim 15. The Commission found
    infringement under the claim 9 alternative—specifically, it
    found that the YddG protein encoded by the codon-random-
    ized non-E. coli yddG gene of this strain is an equivalent of
    SEQ ID NO:2 (the amino-acid sequence of the E. coli YddG
    protein), as required by the protein limitation of claim 9.
    CJ challenges that finding on two grounds. Based on
    an amendment to original claims made during prosecution,
    CJ asserts that prosecution history estoppel bars
    Ajinomoto from relying on the doctrine of equivalents to
    meet the protein limitation. Separately, CJ asserts that
    the non-E. coli YddG protein of CJ’s second later strain
    cannot reasonably be found to be an equivalent of the
    claimed E. coli YddG protein under the function-way-result
    test for equivalence. We address those arguments in turn.
    1
    Under the doctrine of prosecution history estoppel, “[a]
    patentee’s decision to narrow his claims through amend-
    ment may be presumed to be a general disclaimer of the
    territory between the original claim and the amended
    claim.” Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki
    Co., 
    535 U.S. 722
    , 740 (2002). The Supreme Court has
    specified three ways the patentee can rebut that presump-
    tion, each of which, if established, means that “the amend-
    ment cannot reasonably be viewed as surrendering a
    particular equivalent.” 
    Id.
     First, “[t]he equivalent may
    have been unforeseeable at the time of the application.” 
    Id.
    Second, “the rationale underlying the amendment may
    bear no more than a tangential relation to the equivalent
    in question.” 
    Id.
     Third, “there may be some other reason
    suggesting that the patentee could not reasonably be
    AJINOMOTO CO., INC. v. ITC                                   17
    expected to have described the insubstantial substitute in
    question.” 
    Id.
     at 740–41.
    In this case, the relevant facts about what transpired
    during prosecution are as follows. Claim 1 as originally
    filed recited two alternative conditions for the claimed pro-
    tein:
    a protein as defined in the following (A) or (B) in a
    cell of said bacterium:
    (A) a protein which comprises the amino acid se-
    quence shown in SEQ ID NO:2 in Sequence listing;
    (B) a protein which comprises an amino acid se-
    quence including deletion, substitution, insertion
    or addition of one or several amino acids in the
    amino acid sequence shown in SEQ ID NO:2 in Se-
    quence listing.
    J.A. 5047. The examiner rejected that claim as anticipated
    by a reference disclosing the E. coli “yfiK gene product” (i.e.,
    the E. coli YfiK protein)—which differed from SEQ ID
    NO:2 by deletion, substitution, insertion, or addition of sev-
    eral amino acids and, therefore, did not come within the (A)
    alternative but did come within the (B) alternative. J.A.
    5378. In response, the applicants left the (A) alternative
    alone but replaced the language following (B) with new lan-
    guage: “a protein which comprises an amino acid sequence
    that is encoded by a nucleotide sequence that hybridizes
    with the nucleotide sequence of SEQ ID NO:1 under strin-
    gent conditions.” J.A. 5609. 7
    7   As previously noted, claims 9 and 15 issued from
    new claims added at the same time as this amendment.
    See supra note 6. Claims 9 and 15 respectively contain the
    same language as the (A) and (B) limitations in claim 1 af-
    ter it was amended. Claim 20, the claim at issue, treats
    18                                  AJINOMOTO CO., INC. v. ITC
    As an initial matter, CJ’s argument for prosecution his-
    tory estoppel in this case involves an unusual circum-
    stance. The infringement determination does not rest on
    finding an equivalent of the new claim language—namely,
    the (nucleotide) SEQ ID NO:1 language now in claim 15.
    Rather, it rests on finding an equivalent of the (amino-acid)
    SEQ ID NO:2 language now in claim 9, which was not itself
    altered by the amendment at issue. That is, the original
    claim provided two alternatives; only the second was mod-
    ified by amendment; and only the first is asserted as the
    basis for infringement by CJ’s second later strain. But we
    need not reach Ajinomoto’s contention that, in this circum-
    stance, prosecution history estoppel does not apply at all,
    i.e., that there is not even a presumed (though rebuttable)
    surrender of the asserted equivalent. The Commission did
    not so rule, instead concluding that the “tangential rela-
    tion” exception applied, so that Ajinomoto did not surren-
    der the protein produced by the codon-randomized non-E.
    coli yddG gene of CJ’s second later strain. J.A. 41–44. We
    agree with that conclusion. 8
    In applying the “tangential relation” exception, we
    “ask[] whether the reason for the narrowing amendment
    was peripheral, or not directly relevant, to the alleged
    equivalent.” Festo Corp. v. Shoketsu Kinzoku Kogyo Ka-
    bushiki Co., 
    344 F.3d 1359
    , 1369 (Fed. Cir. 2003). “[T]he
    inquiry into whether a patentee can rebut the Festo
    claims 9 and 15 as alternatives in the same way that orig-
    inal and amended claim 1 treated (A) and (B).
    8   CJ contends that Ajinomoto forfeited invocation of
    the “tangential relation” exception because it did not in-
    voke the exception before the ALJ or in its request for re-
    view by the full Commission. CJ cites no authority that
    barred the Commission from exercising discretion to raise
    the issue and give the parties an adequate opportunity to
    address it, as the Commission did here.
    AJINOMOTO CO., INC. v. ITC                                19
    presumption under the ‘tangential’ criterion focuses on the
    patentee’s objectively apparent reason for the narrowing
    amendment.” 
    Id.
     Our cases require the patentee to show
    that the way in which the alleged equivalent departs from
    what the claim limitation literally requires is tangential to
    the discernible objective reason for the narrowing amend-
    ment. In that situation, there is no surrender of the equiv-
    alent by that amendment.
    For instance, in Insituform Technologies, Inc. v. CAT
    Contracting, Inc., the patent claimed a method of using a
    vacuum to impregnate a flexible tube with resin. 
    385 F.3d 1360
    , 1362–63 (Fed. Cir. 2004). The claims were originally
    rejected over a prior-art reference that disclosed a single
    vacuum source located far away from the resin source. 
    Id. at 1369
    . The applicant amended the claim at issue to re-
    quire a single vacuum source placed near the resin source.
    See 
    id.
     at 1368–70. The alleged equivalent used multiple
    vacuum sources. 
    Id.
     at 1369–70. We held that the “tan-
    gential relation” exception applied, observing that the pur-
    pose of the narrowing amendment was to distinguish the
    invention from the prior art based on the location of the
    vacuum source relative to the resin, not to limit the number
    of vacuum sources. 
    Id. at 1370
    .
    Similarly, in Regents of the University of California v.
    Dakocytomation California, Inc., the patented method in-
    volved using DNA testing to detect chromosomal abnor-
    malities. 
    517 F.3d 1364
    , 1369–70 (Fed. Cir. 2008). The
    claim at issue originally recited “disabling the hybridiza-
    tion capacity of repetitive sequences” generally. 
    Id. at 1377
    . The examiner rejected the claim over several prior-
    art references, one of which disclosed disabling hybridiza-
    tion using unique sequence probes. 
    Id. at 1378
    . In re-
    sponse, the applicants amended the claim to recite a
    particular technique of disabling hybridization using block-
    ing nucleic acids. 
    Id.
     The parties stipulated that the added
    “blocking nucleic acid” limitation was limited to human nu-
    cleic acids, but the alleged equivalent used synthetic
    20                                   AJINOMOTO CO., INC. v. ITC
    nucleic acids. 
    Id. at 1376
    . We concluded that the narrow-
    ing amendment was tangential to how the equivalent dif-
    fered from the literal claim limitation: “[I]n narrowing the
    claim to overcome the prior art rejections, the focus of the
    patentees’ arguments centered on the method of blocking—
    not on the particular type of nucleic acid that could be used
    for blocking.” 
    Id. at 1378
    . Indeed, we noted, “the ‘nucleic
    acid’ limitation was never narrowed during prosecution
    and was not at issue in the office action rejecting the
    claims,” and “none of the cited references concerned the
    type of nucleic acid that could perform the blocking, or
    mentioned the accused equivalent.” 
    Id.
    Our decision in Intervet Inc. v. Merial Ltd. is to similar
    effect. In that case, the patent claimed DNA constructs en-
    coding a type of porcine circovirus. 
    617 F.3d 1282
    , 1284
    (Fed. Cir. 2010). The claim at issue originally recited DNA
    sequences from a group of thirteen open reading frames,
    which are portions of a gene that encode a protein. 
    Id.
     at
    1285–86, 1291. The examiner rejected the claim over open
    reading frames from another organism, noting that the
    claim as written could cover open reading frames from any
    organism. 
    Id. at 1291
    . The applicants then amended the
    claim to require that the open reading frames be “of porcine
    circovirus type II.” 
    Id.
     The alleged equivalent was a nu-
    cleotide sequence that was over 99% homologous to one of
    the claimed sequences. 
    Id. at 1286
    . The “tangential rela-
    tion” exception applied to that equivalent, we held, because
    “[t]he rationale for the amendment was to narrow the
    claimed universe of [open reading frames] down to those of
    [porcine circovirus type II], and bore only a tangential re-
    lation to the question of which DNA sequences are and are
    not properly characterized as [porcine circovirus type II].”
    
    Id. at 1292
    .
    This understanding of the “tangential relation” excep-
    tion also underlies cases in which we have held that the
    patentee failed to establish that a narrowing amendment
    was tangential to the equivalent at issue. For example, in
    AJINOMOTO CO., INC. v. ITC                                 21
    Biagro Western Sales, Inc. v. Grow More, Inc., the claims at
    issue, which claimed buffered phosphorus fertilizers, were
    rejected over a prior-art reference disclosing a fertilizer
    that was buffered only when diluted. 
    423 F.3d 1296
    , 1299,
    1306 (Fed. Cir. 2005). In response, the applicant amended
    the claims by adding the limitation “wherein said phospho-
    rous-containing acid or salt thereof is present in an amount
    of about 30 to about 40 weight percent,” explaining that the
    fertilizer must be concentrated and that the amendment
    specified a range for the concentration. 
    Id.
     at 1305–06.
    The alleged equivalent contained phosphorus compounds
    at a concentration of between 59% and 62%. 
    Id. at 1305
    .
    We concluded that the “tangential relation” exception did
    not apply, reasoning that it was “clear from the prosecution
    history that the reason for adding the range limitation was
    to overcome a prior art fertilizer that was not concen-
    trated,” and “both the reason for the amendment and the
    asserted equivalent relate to the concentration of the ferti-
    lizer.” 
    Id. at 1306
    .
    Here, we conclude, the Commission correctly concluded
    that Ajinomoto had rebutted the Festo presumption be-
    cause the amendment was tangential to the equivalent in
    question. The objectively evident rationale for the amend-
    ment was to limit the set of proteins within the claim’s
    scope so that it no longer included the prior-art E. coli YfiK
    protein and, more generally, no longer allowed as wide a
    range of amino acid alterations (hence changes in the pro-
    tein) as original alternative (B), which had allowed “dele-
    tion, substitution, insertion or addition of one or several
    amino acids in the amino acid sequence shown in SEQ ID
    NO: 2.” J.A. 5047. The reason for the amendment had
    nothing to do with choosing among several DNA sequences
    in the redundant genetic code that correspond to the same
    protein. Indeed, it is undisputed that the non-E. coli YddG
    protein produced without codon randomization remains
    within the literal claim scope even after the amendment
    and that the non-E. coli YddG protein is identical whether
    22                                 AJINOMOTO CO., INC. v. ITC
    produced from the codon-randomized or the non-codon-ran-
    domized version of the non-E. coli yddG gene.
    Accordingly, the reason for the narrowing amendment
    —limiting the amino-acid makeup of the proteins included
    in one of the alternatives covered by the claim—is unre-
    lated to differences among the several DNA sequences that
    encode a given protein. Under Festo’s express provision for
    a “tangential relation” exception to the presumption as to
    the scope of surrender by amendment during prosecution,
    this conclusion about the reason for the amendment at is-
    sue does not “ignore[] how the patentee deliberately elected
    to narrow the claims” (Dissent at 6); rather, it identifies
    what was not within the “scope disclaimed” (id. at 7), so
    that it may be proved to infringe by satisfying the other
    requirements of the doctrine of equivalents. We therefore
    reject CJ’s contention that prosecution history estoppel
    precludes the Commission’s finding of infringement under
    the doctrine of equivalents for the second later strain.
    2
    CJ’s second challenge to the Commission’s finding re-
    garding the protein limitation and CJ’s second later strain
    is that the non-E. coli YddG protein of CJ’s second later
    strain could not properly be found to be equivalent to the
    claimed E. coli YddG protein. Ajinomoto presented its
    equivalence case within the function-way-result frame-
    work, under which a product or process that does not liter-
    ally satisfy a claim limitation may nevertheless infringe “if
    it performs substantially the same function in substan-
    tially the same way to obtain the same result.” Duncan
    Parking Techs., Inc. v. IPS Grp., Inc., 
    914 F.3d 1347
    , 1362
    (Fed. Cir. 2019) (quoting Graver Tank & Mfg. Co. v. Linde
    Air Prods. Co., 
    339 U.S. 605
    , 608 (1950)). We conclude that
    substantial evidence supports the Commission’s finding of
    equivalence under that test.
    As to “function”: Ajinomoto’s expert, Dr. Gregory
    Stephanopoulos, testified that both E. coli and non-E. coli
    AJINOMOTO CO., INC. v. ITC                                23
    YddG proteins function as “export protein[s] that actively
    export[] aromatic L-amino acids and aromatic L-amino acid
    analogs” out of the bacterial cell. J.A. 545–46. A 2007 ar-
    ticle by Doroshenko et al. similarly explains that both pro-
    teins are involved in exporting aromatic compounds. See
    J.A. 9451. And Dr. So Young Kim, a CJ employee, testified
    during a deposition that both proteins would be expected
    to have similar functions based on similarities in the or-
    ganisms from which they are derived. See J.A. 10641 (“Q.
    Based on the similarity between E. coli and [the non-E. coli
    organism], you would suspect that the protein coded by the
    [non-E. coli] yddG gene would be useful for whatever it
    does in E. coli, right? A. I think that way too.”). Thus, the
    Commission’s finding that both proteins perform the same
    function is supported by substantial evidence.
    As to “way”: Dr. Stephanopoulos testified that the two
    proteins are 85% to 95% identical in structure. J.A. 546.
    This range was corroborated by a 2002 article by Santivi-
    ago et al., which indicates an 85% structural identity, see
    J.A. 9444, and the Doroshenko article, which notes a 95%
    identity in amino-acid sequence, J.A. 9451. On the record
    here, substantial evidence supports a finding that the two
    proteins perform the membrane-transport function in sub-
    stantially the same way. See also Mylan Institutional LLC
    v. Aurobindo Pharma Ltd., 
    857 F.3d 858
    , 868 (Fed. Cir.
    2017) (noting that the “function” and “way” inquiries often
    overlap or are synonymous).
    As to “result”: Dr. Stephanopoulos testified that, by ex-
    porting L-tryptophan out of the bacterial cell, both proteins
    increase the ability of bacteria to “produce and accumulate
    L-tryptophan.” See J.A. 547. That statement is supported
    by CJ’s fermentation data, which showed that strains con-
    taining the E. coli yddG gene but with a stronger promoter,
    and strains containing the non-E. coli yddG gene with a
    strong promoter, both showed greater production of L-tryp-
    tophan than did strains containing the E. coli yddG gene
    with the native promoter. See J.A. 7957; J.A. 10053. In
    24                                   AJINOMOTO CO., INC. v. ITC
    other words, enhancing the expression of either the E. coli
    or the non-E. coli yddG gene had the effect of increasing
    production of L-tryptophan, which supports an inference
    that the proteins encoded by those genes both result in in-
    creased L-tryptophan production. The Commission’s find-
    ings regarding result are supported by substantial
    evidence.
    CJ argues that the two proteins do not perform the
    same function in the same way because the E. coli YddG
    protein exports aromatic L-amino acids such as L-trypto-
    phan, whereas the non-E. coli YddG protein exports a dif-
    ferent compound—namely, paraquat (also known as
    methyl viologen). But a 2012 article by Liu et al. explains
    that YddG proteins can export both types of compounds.
    See J.A. 9751 (“YddG is classified as aromatic amino
    acid/paraquat exporter . . . .”). And Dr. Stephanopoulos, re-
    lying on the Santiviago article, testified that the non-E. coli
    YddG protein must be coupled to the OmpD protein, which
    is present in the non-E. coli organism but not E. coli, to
    export paraquat. J.A. 762 (citing J.A. 9439). The fact that
    the non-E. coli YddG protein may be involved in exporting
    compounds other than L-tryptophan in the non-E. coli or-
    ganism does not undermine the Commission’s well-sup-
    ported finding that the non-E. coli YddG protein is involved
    in exporting L-tryptophan in the E. coli bacteria used by
    CJ.
    B
    CJ challenges the Commission’s finding of infringe-
    ment of both later strains on one additional ground. The
    Commission found that CJ’s later strains met the re-
    sistance limitation. CJ argues that substantial evidence
    AJINOMOTO CO., INC. v. ITC                                 25
    does not exist to support that finding. 9 We reject that ar-
    gument.
    Several pieces of evidence indicate that, as a general
    matter, enhancing the activity of the YddG protein in-
    creases bacteria’s resistance to L-tryptophan. Table 1 of
    the ’655 patent shows that E. coli bacteria with multiple
    copies of the yddG gene introduced through plasmids
    demonstrated better growth on a tryptophan substrate,
    and thus more resistance, than unmodified E. coli bacteria.
    See ’655 patent, col. 9, lines 50–65 (bottom row, compare
    column “pUC19” (-) with column “pYDDG1” (+)). Similarly,
    the Doroshenko article, mentioned above, describes an ex-
    periment in which E. coli bacteria with a stronger promoter
    preceding the yddG gene demonstrated enhanced re-
    sistance to L-tryptophan. See J.A. 9455 (row DV036, col-
    umn DL-5-f-Trp).
    CJ’s fermentation data, mentioned above, also provides
    direct evidence that CJ’s later strains have increased re-
    sistance to L-tryptophan. That data shows a greater vol-
    ume of tryptophan with both of CJ’s later strains than with
    unmodified E. coli bacteria. See J.A. 7957 (first later
    strain: middle table, row F4, column “Volume produced”);
    J.A. 10053 (second later strain: row “Product (g)” toward
    middle of table). Dr. Stephanopoulos indicated that a
    strain’s ability to overproduce L-tryptophan necessarily
    meant that the strain had increased resistance to L-trypto-
    phan. See J.A. 1448 (“[I]f that product feedback inhibits its
    own synthesis, clearly, this is not going to work.”); see also
    9     CJ does not challenge the finding that CJ’s first
    later strain meets the protein limitation of the claim 15 al-
    ternative of claim 20. Specifically, CJ’s first later strain
    uses a non-E. coli yddG gene without codon randomization,
    which hybridizes with the complement of SEQ ID NO:1
    (i.e., the nucleotide sequence of the E. coli yddG gene), and
    thus falls within the literal scope of claim 15.
    26                                 AJINOMOTO CO., INC. v. ITC
    J.A. 521 (stating that bacteria that “exhibit enhanced re-
    sistance to an aromatic L-amino acid or an aromatic L-
    amino acid analog” also “overproduce the corresponding ar-
    omatic L-amino acid analog”).
    CJ’s objections to the sufficiency or even relevance of
    this evidence are unpersuasive. CJ points out that the bac-
    teria used to generate the data in Table 1 of the ’655 patent
    contained plasmids with more than the two copies of the
    yddG gene in CJ’s later strains. See J.A. 1229. The Doro-
    shenko article, however, indicates that enhancing the ac-
    tivity of even a single copy of the yddG gene can increase
    resistance to L-tryptophan. CJ responds that the strain
    studied in Doroshenko used a strong λPL promoter, while
    CJ’s later strains use relatively weaker non-E. coli native
    yddG, rmf, and rhtB promoters. See J.A. 9454. But Dr.
    Stephanopoulos testified that at least the rmf promoter in
    both of CJ’s later strains also is more potent than the na-
    tive E. coli yddG promoter. J.A. 554. Thus, even if CJ is
    correct that its later strains do not contain tandem promot-
    ers, the Commission could reasonably infer that the pro-
    moters used in CJ’s later strains enhance the activity of the
    yddG genes relative to unmodified E. coli bacteria and
    thereby increase those strains’ resistance to L-tryptophan.
    CJ also cites Ajinomoto’s 2002 Progress Report as evi-
    dence that enhancing a single copy of the yddG gene is in-
    sufficient to enhance resistance to L-tryptophan. That
    report states that an experiment using “only one copy” of
    the yddG gene with a PL promoter “does not correctly
    model[]” an earlier experiment using a “moderate-copy-
    number” plasmid with the yddG gene, which had shown a
    “positive effect” of the yddG gene on tryptophan produc-
    tion. J.A. 10268. No more need be inferred from the report
    than that enhancing a single copy of the yddG gene in-
    creases resistance to L-tryptophan less than using a
    greater number of copies. The Commission did not need to
    infer that enhancing a single copy as in CJ’s later strains
    does not enhance resistance at all.
    AJINOMOTO CO., INC. v. ITC                                27
    Further, CJ asserts that the increased production of L-
    tryptophan, and thus the enhanced resistance to L-trypto-
    phan, observed in its later strains could be attributable to
    the presence of other genetic mutations rather than to in-
    creased YddG protein activity alone. See J.A. 442. But the
    claims require only that the protein “has the activity to
    make the bacterium resistant” to L-tryptophan, not that
    the protein be the sole cause of the bacterium’s enhanced
    resistance to L-tryptophan. See ’655 patent, col. 22, lines
    57–59. Considering the already-mentioned evidence that
    the YddG protein generally has the effect of increasing re-
    sistance to L-tryptophan, the Commission had substantial
    evidence from which to find that it was more likely than
    not that increased activity of the YddG protein at least
    partly contributed to the enhanced resistance of CJ’s later
    strains.
    C
    CJ’s final contention in its cross-appeal seeks reversal
    of the Commission’s rejection of CJ’s invalidity challenge to
    claim 20. CJ argues that substantial evidence does not
    support the Commission’s finding that CJ did not prove
    lack of an adequate written description for the genus of
    “more potent promoter[s]” recited in claims 9 and 15 and,
    by incorporation, in claim 20. We reject CJ’s argument.
    “[A] sufficient description of a genus . . . requires the
    disclosure of either a representative number of species fall-
    ing within the scope of the genus or structural features
    common to the members of the genus so that one of skill in
    the art can ‘visualize or recognize’ the members of the ge-
    nus.” Ariad Pharm., Inc. v. Eli Lilly & Co., 
    598 F.3d 1336
    ,
    1350 (Fed. Cir. 2010) (en banc). The Commission found
    both that the ’655 patent discloses a representative number
    of species of more potent promoters and that there are
    structural features common to the genus of more potent
    promoters. Both of those findings are supported by
    28                                  AJINOMOTO CO., INC. v. ITC
    substantial evidence, and they suffice to uphold the Com-
    mission’s rejection of CJ’s written-description challenge.
    1
    As to a representative number of species, we have rec-
    ognized that the amount of disclosure necessary to satisfy
    the written-description requirement “will necessarily vary
    depending on the context,” considering such facts as “the
    existing knowledge in the particular field, the extent and
    content of the prior art, the maturity of the science or tech-
    nology,” and “the predictability of the aspect at issue.” Ar-
    iad, 
    598 F.3d at 1351
     (quoting Capon v. Eshhar, 
    418 F.3d 1349
    , 1359 (Fed. Cir. 2005)). In some circumstances, we
    have added, “a patentee may rely on information that is
    ‘well-known in the art’ for purposes of meeting the written
    description requirement,” because “the specification is
    viewed from the perspective of one of skill” in the relevant
    art. Bos. Sci. Corp. v. Johnson & Johnson, 
    647 F.3d 1353
    ,
    1366 (Fed. Cir. 2011).
    The ’655 patent discloses four examples of “potent pro-
    moters”: “PL promoter of lambda phage,” the “lac pro-
    moter,” the “trp promoter,” and the “trc promoter.” ’655
    patent, col. 6, lines 21–24. The patent also cites the 1986
    article by Deuschle et al. as disclosing “examples of potent
    promoters” and “[m]ethods for [the] evaluation [of] the
    strength of promoter[s].” 
    Id.,
     col. 6, lines 16–21. That ar-
    ticle provides data about the relative strength of fourteen
    promoters and describes a general methodology for deter-
    mining promoter strength in E. coli bacteria. J.A. 6174–
    77. This evidence supports the Commission’s finding that
    “enhancing promoter activity was well-known” and that a
    skilled artisan “would have been able to identify more po-
    tent promoters by employing common tools for measuring
    RNA transcription.” J.A. 46.
    The ’655 patent also makes clear that its invention was
    “identifying the yddG gene encoding a membrane protein”
    and discovering that the gene “conferred on a
    AJINOMOTO CO., INC. v. ITC                                29
    microorganism resistance to phenylalanine and several
    amino acid analogues” when the gene was amplified or its
    expression enhanced, see ’655 patent, col. 2, lines 46–57,
    not the well-known techniques for performing the amplifi-
    cation or expression enhancement, see 
    id.,
     col. 5, line 57,
    through col. 6, line 33. We have explained that the repre-
    sentative-species inquiry is directed to whether the inven-
    tor “has truly invented the genus” as opposed to “a research
    plan, leaving it to others to explore the unknown contours
    of the claimed genus.” AbbVie Deutschland GmbH & Co.,
    KG v. Janssen Biotech, Inc., 
    759 F.3d 1285
    , 1300 (Fed. Cir.
    2014). Here, the genus of more potent promoters was al-
    ready well explored in the relevant art by the time of the
    ’655 patent’s invention. In these circumstances, the Com-
    mission permissibly found in the specification, read in light
    of the background knowledge in the art, a representative
    number of species for the genus of more potent promoters.
    2
    As to a common structural feature, the Commission
    found that a skilled artisan could “identify more potent
    yddG promoters given the well-known link between con-
    sensus sequence and promoter strength,” i.e., that promot-
    ers having fewer departures from a “consensus sequence”
    in a promoter are generally stronger than promoters with
    more departures from such a sequence. J.A. 46. 10 Substan-
    tial evidence supports that finding. For instance, a 1983
    article by Hawley and McClure describes a study demon-
    strating that most “mutations that decrease initiation fre-
    quency also decrease the homology of the promoter to the
    consensus sequence, while up-mutations increase the
    10 The consensus sequence is a specific nucleotide se-
    quence that appears in the promoters associated with
    many different genes in the genome of a particular organ-
    ism. In E. coli, the consensus sequence has two parts:
    TTGACA at the -35 region and TATAAT at the -10 region.
    30                                 AJINOMOTO CO., INC. v. ITC
    homology in” most instances. J.A. 6237. Similarly, a 1986
    article by Horwitz and Loeb explains that “mutations that
    increase transcription, ‘up mutations,’ usually increase ho-
    mology with the consensus sequence and spacing,” while
    “mutations that decrease transcription, ‘down mutations,’
    usually decrease homology with the consensus sequence
    and spacing.” J.A. 6251.
    CJ disputes that similarity to the consensus sequence
    defines a common structural feature, citing several articles
    as indicating that a promoter closer to the consensus se-
    quence will not always be stronger than one farther from
    that sequence. For instance, a 1998 article by Jensen and
    Hammer reports that a pattern observed in another organ-
    ism—that “the relatively strong promoters were the perfect
    ones,” i.e., those closer to the consensus sequence—“did not
    hold true for E. coli: here the promoters which had either
    an error in the consensus sequence or a shorter spacer were
    relatively strong.” J.A. 9149. Moreover, a 1985 article by
    Aoyama and Takanami states that similarity to the con-
    sensus sequence “is still not enough to predict the site and
    strength of promoter from a given sequence,” J.A. 6215,
    and a 1999 book edited by Fernandez and Hoeffler notes
    that “the strongest promoters in E. coli do not necessarily
    adhere to the consensus sequence,” J.A. 9113.
    CJ’s argument both assumes too strict a legal standard
    and reads too much into its cited references. Adequate
    written description does not require a perfect correspond-
    ence between the members of the genus and the asserted
    common structural feature; for a functionally defined ge-
    nus like the one at issue here, we have spoken more mod-
    estly of a “correlation between structure and function.”
    Ariad, 
    598 F.3d at 1350
     (emphasis added). In any event,
    CJ’s evidence at most establishes that, starting with the
    consensus sequence, deviations from that sequence do not
    always decrease promoter strength, at least in E. coli. But
    the genus at issue here is “more potent promoter[s]” than
    the native promoter, not less potent promoters than the
    AJINOMOTO CO., INC. v. ITC                                 31
    consensus sequence. And the Commission had substantial
    evidence from which to find that, starting from the native
    E. coli yddG promoter, deviations toward the consensus se-
    quence generally increase promoter strength.
    The cases cited by CJ in which we have held genus
    claims to lack an adequate written description are inappo-
    site. In Boston Scientific, the specification contained “no
    examples of macrocyclic lactone analogs of rapamycin” (the
    claimed genus) and essentially “no guidance on how to
    properly determine whether a compound is a macrocyclic
    lactone analog of rapamycin.” 
    647 F.3d at 1364
    . In AbbVie,
    there was “no evidence to show any described antibody to
    be structurally similar to, and thus representative of,” an
    antibody accused of coming within the claim, nor was there
    “evidence to show whether one of skill in the art could make
    predictable changes to the described antibodies to arrive at
    other types of antibodies such as” the accused antibody.
    759 F.3d at 1301. And in Regents of the University of Cali-
    fornia v. Eli Lilly & Co., the specification described “a pro-
    cess for obtaining human insulin-encoding cDNA” (such
    cDNA required by the claim at issue) but not any “sequence
    information indicating which nucleotides constitute hu-
    man cDNA” or “further information in the patent pertain-
    ing to that cDNA’s relevant structural or physical
    characteristics.” 
    119 F.3d 1559
    , 1567 (Fed. Cir. 1997).
    Here, by contrast, the ’655 patent expressly provides four
    examples of “more potent promoters,” and the Commission
    supportably found that a skilled artisan could make rela-
    tively predictable changes to the native promoter to arrive
    at a more potent promoter.
    IV
    For the foregoing reasons, we affirm the Commission’s
    decision.
    No costs.
    AFFIRMED
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    AJINOMOTO CO., INC., AJINOMOTO HEARTLAND
    INC.,
    Appellants
    v.
    INTERNATIONAL TRADE COMMISSION,
    Appellee
    CJ CHEILJEDANG CORP., CJ AMERICA, INC., PT
    CHEIJEDANG INDONESIA,
    Intervenors
    --------------------------------------------
    CJ CHEILJEDANG CORP., CJ AMERICA, INC., PT
    CHEIJEDANG INDONESIA,
    Appellants
    v.
    INTERNATIONAL TRADE COMMISSION,
    Appellee
    AJINOMOTO CO., INC., AJINOMOTO HEARTLAND
    INC.,
    Intervenors
    ______________________
    2018-1590, 2018-1629
    ______________________
    2                                     AJINOMOTO CO., INC. v. ITC
    Appeals from the United States International Trade
    Commission in Investigation No. 337-TA-1005.
    ______________________
    DYK, Circuit Judge, concurring-in-part and dissenting-in-
    part.
    I join the majority as to parts I, II, III (B) (as it relates
    to Strain A, corresponding to the “first later strain” in the
    majority) and (C). I respectfully dissent from the majority’s
    conclusion that Ajinomoto successfully rebutted the pre-
    sumption of prosecution history estoppel under the tangen-
    tial exception as to respondent’s recombinant bacterial
    Strain B, which corresponds to the “second later strain” re-
    ferred to by the majority, see Majority Op. at 15.
    On appeal, the only asserted claim is claim 20 of 
    U.S. Patent No. 7,666,655
     (’655 patent). It covers “[a] method for
    producing an [amino acid,] which comprises cultivating the
    bacterium according to any one of claims 9[, or 15].” ’655
    patent, col. 24, ll. 4–6. In relevant part, claim 9 covers a
    recombinant bacteria having a “protein consist[ing] of the
    amino acid sequence of SEQ ID NO: 2.” 
    Id.
     col. 22, ll. 56–
    57. This corresponds to the amino acid sequence of E. coli
    YddG protein (a membrane-bound protein involved in the
    cellular export of aromatic amino acids). Strain B does not
    literally infringe claim 9 because it produces a protein with
    an amino acid sequence that differs from SEQ ID NO: 2.
    See J.A. 37. Instead, Ajinomoto asserts infringement under
    the doctrine of equivalents, arguing that Strain B’s non-E.
    coli YddG protein is equivalent to the E. coli YddG protein
    (SEQ ID NO: 2) in claim 9.
    The prosecution history shows that claim language was
    amended such that the accused equivalent is excluded. 1
    1   Everyone agrees that the relevant prosecution his-
    tory for the analysis focuses on the language in claim 1,
    AJINOMOTO CO., INC. v. ITC                                   3
    Originally, the claim language covered variations of SEQ
    ID NO: 2, stating that it covered “deletion, substitution, in-
    sertion or addition of one or several amino acids” of SEQ ID
    NO: 2. J.A. 5609. During prosecution, the examiner re-
    jected the claim as anticipated by prior art (Livshits) that
    disclosed a recombinant E. coli bacteria producing YfiK
    protein, encoded by the yfiK gene, which had an amino acid
    sequence different from the SEQ ID NO: 2 but still satis-
    fied the claim limitations. J.A. 5378. Specifically, the ex-
    aminer stated “Livshits et al. anticipate claims 1-4 because
    the yfiK gene product can be considered a protein” meeting
    the claim limitation above. 
    Id.
     In response to this rejection,
    the patentee narrowed the claim language (which now ap-
    pears in claim 15) to only cover protein variants differing
    from SEQ ID NO: 2 when they are “encoded by a nucleotide
    sequence that hybridizes with the nucleotide sequence of
    SEQ ID NO: 1[, the E. coli yddG gene,] under stringent con-
    ditions comprising 60°C, 1 x SSC, 0.1% SDS.” J.A. 5609;
    see ’655 patent, col. 23, ll. 19–22. 2 The patentee stated that
    “[i]n view of this amendment, Livshits et al no longer an-
    ticipates the claimed invention.” J.A. 5617.
    The majority assumes that prosecution history estop-
    pel presumptively applies in this case. Majority Op. at 18.
    But the majority concludes that Ajinomoto is still not pre-
    cluded from arguing infringement under the doctrine of
    equivalents based on the tangential exception.
    We have consistently described this exception as “very
    narrow.” Integrated Tech. Corp. v. Rudolph Techs., Inc.,
    
    734 F.3d 1352
    , 1358 (Fed. Cir. 2013) (quoting Cross Med.
    which was later utilized in claims 9 and 15 that were added
    later in prosecution.
    2    Strain B does not literally infringe claim 15 be-
    cause the non-E. coli YddG protein’s encoding nucleotide
    sequence does not hybridize with SEQ ID NO: 1 under the
    claimed conditions.
    4                                  AJINOMOTO CO., INC. v. ITC
    Prods., Inc. v. Medtronic Sofamor Danek, Inc., 
    480 F.3d 1335
    , 1342 (Fed. Cir. 2007)). Under this exception, the
    question is “whether the reason for the narrowing amend-
    ment was peripheral, or not directly relevant, to the alleged
    equivalent.” Festo Corp. v. Shoketsu Kinzoku Kogyo Ka-
    bushiki Co., 
    344 F.3d 1359
    , 1369 (Fed. Cir. 2003) (en banc).
    The inquiry “focuses on the patentee’s objectively apparent
    reason for the narrowing amendment,” which “should be
    discernible from the prosecution history record.” 
    Id.
     (em-
    phasis added). In my view the “reason for the narrowing
    amendment” in this case is directly related to the equiva-
    lent.
    Originally, the claim covered proteins with amino acid
    sequence variations from SEQ ID NO: 2, which would have
    included the non-E. coli YddG protein at issue here. The
    examiner rejected the original claim based on anticipating
    prior art, and the patentee responded with a narrowing
    amendment. Instead of continuing to define the covered
    proteins in terms of amino acid sequence variations from
    SEQ ID NO: 2, 3 the patentee deliberately chose to redefine
    the claimed proteins in terms of the ability of their encod-
    ing nucleotide sequences to hybridize with SEQ ID NO: 1
    under the claimed conditions. The amended claim lan-
    guage excluded the prior art protein (Livshits) because it
    was made based on a nucleotide sequence that did not meet
    the newly added hybridization requirement. The accused
    equivalent is similarly not covered by the amended claims
    because it is produced based on an encoding nucleotide se-
    quence that does not hybridize with SEQ ID NO: 1 under
    the claimed conditions. Thus, I do not see how the reason
    3    The patentee later added claim language that cov-
    ered other, more limited, variations from the amino acid
    sequence of SEQ ID NO: 2, by “one to five amino acids,” but
    that claim language is not at issue here. ’655 Patent, col.
    21, l. 42.
    AJINOMOTO CO., INC. v. ITC                                  5
    for the narrowing amendment is tangential to the accused
    equivalent.
    Ajinomoto argues that “[t]o the extent anything was
    given up during prosecution, it was the YfiK protein [dis-
    closed in Livshits] . . . and, possibly, other non-YddG pro-
    teins.” Ajinomoto Response & Reply Br. at 41 (emphasis
    omitted). Ajinomoto’s argument that prosecution history
    estoppel would only apply to the specific prior art protein
    (or possibly other non-YddG proteins) is not only incon-
    sistent with how the patentee amended the claims but also
    our caselaw. Specifically, “[Ajinomoto’s] representations
    convey to the public that it was relying on [the claimed hy-
    bridization requirement] to overcome the prior art. The
    public is entitled to rely on those representations.” Inte-
    grated Tech., 734 F.3d at 1359. “The fact that the inventors
    may have thought after the fact that they could have relied
    on other distinctions in order to defend their claims[, e.g.,
    by limiting the claim to only YddG-type proteins,] is irrele-
    vant and speculative . . . .” Schwarz Pharma, Inc. v. Pad-
    dock Labs., Inc., 
    504 F.3d 1371
    , 1377 (Fed. Cir. 2007). “It is
    not relevant to the determination of the scope of the sur-
    render that the applicant did not need to amend the claims”
    in the way that it chose to do so “in order to overcome the
    prior art.” Lucent Techs., Inc. v. Gateway, 
    525 F.3d 1200
    ,
    1218 (Fed. Cir. 2008) (citing Norian Corp v. Stryker Corp.,
    
    432 F.3d 1356
    , 1361–62 (Fed. Cir. 2005)).
    The majority adopts a slightly different version of
    Ajinomoto’s untenable argument. The majority concludes
    that the “objectively evident rationale” for the narrowing
    amendment was “to limit the set of proteins within the
    claim’s scope so that it no longer included the prior-art
    [protein], and, more generally, no longer allowed as wide a
    range of amino acid alterations.” Majority Op. at 21 (em-
    phasis in original). The majority reasons that because
    Strain A, which makes the same protein as Strain B but
    with a different nucleotide sequence, literally infringes
    claim 15, somehow Strain B should be found to infringe
    6                                   AJINOMOTO CO., INC. v. ITC
    claim 9 under the doctrine of equivalents. It theorizes that
    “[t]he reason for the amendment had nothing to do with
    choosing among several DNA sequences in the redundant
    genetic code that correspond to the same protein” (i.e., the
    accused equivalent). Id. at 21. In this way, the majority
    concludes that the reason for the narrowing amendment—
    limiting the range of proteins covered by the claim—is un-
    related to the way in which the equivalent departs from the
    literal claim limitation—differences among the several
    DNA sequences that encode a given protein.
    The problem with the majority’s analysis is that it ig-
    nores how the patentee deliberately elected to narrow the
    claims. The anticipating prior art disclosed E. coli YfiK pro-
    tein, encoded by the yfiK gene, and this prior art was
    avoided by narrowing the claim to only cover certain encod-
    ing nucleotide sequences. That rationale is directly related
    to the accused equivalent, which does not infringe because
    it does not use a covered encoding nucleotide sequence. In
    other words, the rationale for the narrowing amendment
    (avoiding a prior art protein based on its encoding nucleo-
    tide sequence that does not meet the newly claimed hybrid-
    ization requirement) directly relates to the accused
    equivalent (a protein made by an encoding nucleotide se-
    quence that does not meet the newly claimed hybridization
    requirement).
    The cases cited by the majority also do not support its
    approach. In Insituform Technologies, Inc. v. CAT Con-
    tracting, Inc., 
    385 F.3d 1360
     (Fed. Cir. 2004), and Regents
    of the University of California v. Dakocytomation Califor-
    nia, 
    517 F.3d 1364
     (Fed. Cir. 2008), multiple limitations
    were added with a narrowing amendment but only one of
    those limitations related to what was taught in the prior
    art cited by the examiner. We held that the equivalent to
    the other limitation was permitted under the tangential ex-
    ception. In Insituform, the rationale for the amendment
    was to limit the location of the vacuum source, not the num-
    ber of vacuum sources (the accused equivalent). 385 F.3d
    AJINOMOTO CO., INC. v. ITC                                 7
    at 1370. In Regents, the rationale for the amendment was
    to limit the type of blocking method, not the particular
    types of nucleic acids that could be used in that method (the
    accused equivalent). 
    517 F.3d at 1378
    . These cases cannot
    be read as allowing the patentee to recapture scope dis-
    claimed in order to distinguish the prior art, which is ex-
    actly what the patentee is attempting to do here. The
    anticipating prior art cited by the examiner specifically
    taught a protein made by a particular gene, and the pa-
    tentee narrowed the claim to avoid this prior art by limit-
    ing the claim to only cover proteins made by particular
    nucleotide sequences (which neither the prior art nor
    Strain B have).
    Our decision in Intervet Inc. v. Merial Ltd., 
    617 F.3d 1282
     (Fed. Cir. 2010), is also inapposite. There, the claims
    were “narrow[ed from] the claimed universe of [nucleotide
    sequences] down to those of [porcine circovirus type II
    (‘PCV-2’)],” but there remained the tangential “question of
    which DNA sequences are and are not properly character-
    ized as PCV-2.” 
    Id. at 1292
     (emphasis added). In contrast,
    there is no question here of which nucleotide sequences are
    “properly characterized” as being included under the claim
    language—only those that hybridize with SEQ ID NO: 1
    “under stringent conditions comprising 60°C, 1 x SSC,
    0.1% SDS” are covered. J.A. 5609. There is no dispute that
    CJ’s bacterial strain does not satisfy this specific and un-
    ambiguous limitation.
    In my view the tangential exception cannot apply. The
    equivalent is directly related to the reason for the amend-
    ment—to exclude those proteins made by an encoding nu-
    cleotide sequence that does not hybridize with SEQ ID
    NO: 1 under the specified conditions. I respectfully dissent
    from the majority’s contrary conclusion.
    

Document Info

Docket Number: 18-1590

Citation Numbers: 932 F.3d 1342

Filed Date: 8/6/2019

Precedential Status: Precedential

Modified Date: 1/12/2023

Authorities (20)

Norian Corp. v. Stryker Corp. , 432 F.3d 1356 ( 2005 )

Boston Scientific Corp. v. Johnson & Johnson , 647 F.3d 1353 ( 2011 )

Schwarz Pharma, Inc. v. Paddock Laboratories, Inc. , 504 F.3d 1371 ( 2007 )

Aspex Eyewear, Inc. v. Marchon Eyewear, Inc. , 672 F.3d 1335 ( 2012 )

Ariad Pharmaceuticals, Inc. v. Eli Lilly and Co. , 598 F.3d 1336 ( 2010 )

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Regents of University v. Dakocytomation California, Inc. , 517 F.3d 1364 ( 2008 )

Lucent Technologies, Inc. v. Gateway, Inc. , 525 F.3d 1200 ( 2008 )

Intervet Inc. v. Merial Limited , 617 F.3d 1282 ( 2010 )

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Graver Tank & Mfg. Co. v. Linde Air Products Co. , 70 S. Ct. 854 ( 1950 )

Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. , 122 S. Ct. 1831 ( 2002 )

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