Ariosa Diagnostics v. Verinata Health, Inc. , 805 F.3d 1359 ( 2015 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    ARIOSA DIAGNOSTICS,
    Appellant
    v.
    VERINATA HEALTH, INC.,
    Appellee
    ______________________
    2015-1215, 2015-1226
    ______________________
    Appeals from the United States Patent and Trade-
    mark Office, Patent Trial and Appeal Board in Nos.
    IPR2013-00276, IPR2013-00277.
    ______________________
    Decided: November 16, 2015
    ______________________
    MARK A. LEMLEY, Durie Tangri LLP, San Francisco,
    CA, argued for appellant. Also represented by DARALYN
    JEANNINE DURIE, ALEXANDRA HELEN MOSS; GREG
    GARDELLA, Oblon, Spivak, McClelland, Maier & Neustadt,
    LLP, Alexandria VA.
    EDWARD R. REINES, Weil, Gotshal & Manges LLP,
    Redwood Shores, CA, argued for appellee. Also represent-
    ed by DEREK C. WALTER, ANANT N. PRADHAN; MICHAEL T.
    ROSATO, Wilson, Sonsini, Goodrich & Rosati, PC, Seattle,
    WA.
    ______________________
    2              ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    Before PROST, Chief Judge, WALLACH, and TARANTO,
    Circuit Judges.
    TARANTO, Circuit Judge.
    Verinata Health, Inc. owns U.S. Patent No. 8,318,430,
    which describes and claims methods of noninvasive pre-
    natal testing for the presence of fetal chromosomal ab-
    normalities. In particular, the methods may identify
    “aneuploidy,” i.e., the presence of an abnormal number of
    copies of a chromosome—say, three rather than the
    normal two for chromosome 21, an abnormality that
    characterizes Down Syndrome. The methods involve
    obtaining blood samples from several pregnant women;
    isolating from the samples genomic DNA molecules not
    contained in cells; choosing particular DNA sequences—
    some on a chromosome of concern, some not; indexing by
    maternal source the chromosomes or regions containing
    those sequences; amplifying (making many copies of) the
    group of chromosomes or regions; performing massively
    parallel sequencing on the resulting pool; using the index-
    ing to count, for a particular maternal source, the number
    of sequences from chromosomes of concern versus the
    number from reference chromosomes or regions; and
    determining based on the comparison whether there are
    fetal chromosomal abnormalities, such as an extra copy of
    a chromosome of concern.
    Ariosa Diagnostics, Inc. petitioned the Patent Trial
    and Appeal Board for inter partes review of claims 1–18
    and, in a separate petition, claims 19–30, challenging the
    claims for obviousness under 35 U.S.C. § 103. The Board
    concluded that Ariosa had not met its burden of proving
    that claims 1–18 and 19–30 would have been obvious.
    Ariosa Diagnostics v. Verinata Health, Inc., IPR2013-276,
    
    2014 WL 5454541
    (PTAB Oct. 23, 2014); Ariosa Diagnos-
    tics v. Verinata Health, Inc., IPR2013-277, 
    2014 WL 5454542
    (PTAB Oct. 23, 2014). We vacate the decisions
    and remand for further consideration because of one
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.             3
    matter that the Board’s language suggests it did not
    sufficiently consider. 1
    BACKGROUND
    Verinata and Ariosa are competitors in the relatively
    new field of noninvasive prenatal diagnostics, which
    includes testing for fetal chromosomal abnormalities. For
    many years, prenatal chromosomal testing required
    invasive, high-risk procedures, such as amniocentesis.
    Noninvasive tests, based on the combination of ultra-
    sound observation and measurement of biochemical
    markers in blood samples drawn from the pregnant
    woman, suffered from low accuracy—in a matter where
    accuracy is very important. The 1997 discovery of cell-
    free fetal DNA circulating in maternal blood suggested
    the possibility of superior noninvasive tests, but turning
    the possibility into a reality presented significant chal-
    lenges.
    One challenge involved the proportion of the total
    amount of cell-free DNA in maternal blood that came
    from the fetus. That proportion is typically less than 10
    percent. Some scientists seeking to use the 1997 discov-
    ery focused on distinguishing fetal DNA from maternal
    DNA in a blood sample. By separating fetal from mater-
    nal DNA, or determining the particular fetal/maternal
    ratio of cell-free DNA, certain counting methods could try
    to discern which fetus-specific chromosomes had an
    abnormal number of copies.
    Verinata’s ’430 patent, with a priority date of January
    2010, does not rely on separating fetal from maternal cell-
    free DNA or, even, determining the fetal/maternal ratio of
    cell-free DNA. ’430 patent, col. 5, lines 63–65. Rather,
    1    The Board’s decisions are the same in all respects
    material to this opinion. Instead of providing duplicative
    citations, we cite only the decision in IPR2013-276, which
    we call simply “Ariosa.”
    4                ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    the ’430 patent describes a counting technique applied to
    an overall pool of DNA segments, selected for comparing a
    chromosome of concern (say, chromosome 21) with a
    reference chromosome (or chromosomal region), making
    the comparison by identifying the respective DNA se-
    quences. Fetal aneuploidy (in the case of, for example,
    three versus two copies of a chromosome) may be deter-
    mined by comparing the number of sequences generated
    from the chromosome of concern with the number of
    sequences generated from a reference chromosome—
    counting copies from all cell-free DNA, whether fetal or
    maternal. 
    Id., col. 13,
    lines 59–64. But because cell-free
    fetal DNA is such a small proportion of total cell-free
    DNA, the elevation in the target-sequence count will be
    small in an overall sample; and for the numerical eleva-
    tion to be significant and sufficiently reliable for prenatal
    testing, a large sample must be created and sequenced.
    The ’430 patent describes doing so by amplifying the
    target and reference sequences, pooling samples from
    several women and indexing them for later identification,
    and using massively parallel sequencing. ’430 patent, col.
    1, lines 41–48; 
    id., col. 6,
    lines 20–27; 
    id., col. 12,
    lines 56–
    63.
    Claim 1 of the patent states:
    1. A method for determining a presence or ab-
    sence of a fetal aneuploidy in a fetus for each of a
    plurality of maternal blood samples obtained from
    a plurality of different pregnant women, said ma-
    ternal blood samples comprising fetal and mater-
    nal cell-free genomic DNA, said method
    comprising:
    (a) obtaining a fetal and maternal cell-free ge-
    nomic DNA sample from each of the plurality
    of maternal blood samples;
    (b) selectively enriching a plurality of non-
    random polynucleotide sequences of each fetal
    and maternal cell-free genomic DNA sample
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.              5
    of (a) to generate a library derived from each
    fetal and maternal cell-free genomic DNA
    sample of enriched and indexed fetal and ma-
    ternal non-random polynucleotide sequences,
    wherein each library of enriched and indexed
    fetal and maternal non-random polynucleo-
    tide sequences includes an indexing nucleo-
    tide sequence which identifies a maternal
    blood sample of the plurality of maternal
    blood samples,
    wherein said plurality of non-random polynu-
    cleotide sequences comprises at least 100 dif-
    ferent non-random polynucleotide sequences
    selected from a first chromosome tested for
    being aneuploid and at least 100 different
    non-random polynucleotide sequences select-
    ed from a reference chromosome, wherein the
    first chromosome tested for being aneuploid
    and the reference chromosome are different,
    and wherein each of said plurality of non-
    random polynucleotide sequences is from 10
    to 1000 nucleotide bases in length,
    (c) pooling the libraries generated in (b) to pro-
    duce a pool of enriched and indexed fetal and
    maternal non-random polynucleotide se-
    quences;
    (d) performing massively parallel sequencing of
    the pool of enriched and indexed fetal and
    maternal non-random polynucleotide se-
    quences of (c) to produce sequence reads cor-
    responding to enriched and indexed fetal and
    maternal non-random polynucleotide se-
    quences of each of the at least 100 different
    non-random polynucleotide sequences select-
    ed from the first chromosome tested for being
    aneuploid and sequence reads corresponding
    to enriched and indexed fetal and maternal
    6               ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    non-random polynucleotide sequences of each
    of the at least 100 different non-random poly-
    nucleotide sequences selected from the refer-
    ence chromosome;
    (e) based on the indexing nucleotide sequence,
    for each of the plurality of maternal blood
    samples, enumerating sequence reads corre-
    sponding to enriched and indexed fetal and
    maternal non-random polynucleotide se-
    quences selected from the first chromosome
    tested for being aneuploid and sequence reads
    corresponding to enriched and indexed fetal
    and maternal non-random polynucleotide se-
    quences selected from the reference chromo-
    some; and
    (f) for each of the plurality of maternal blood
    samples, determining the presence or absence
    of a fetal aneuploidy comprising using a num-
    ber of enumerated sequence reads correspond-
    ing to the first chromosome and a number of
    enumerated sequence reads corresponding to
    the reference chromosome of (e).
    ’430 patent, col. 63, lines 8–67. Claims 2–18 depend on
    claim 1 and add various limitations, such as the number
    of non-random DNA sequences selected, the length of the
    non-random DNA sequences, and the chromosomes to be
    tested. 
    Id., col. 64,
    line 8 through col. 65, line 11. Claim
    19, the only other independent claim, differs from claim 1
    in that claim 19 requires comparing the tested chromo-
    some region to a chromosome control region, rather than
    comparing a tested chromosome to a reference chromo-
    some. 
    Id., col. 65,
    lines 35–36, 55–56, 65, and col. 66, line
    7. Claims 20–30 depend on claim 19 and are largely
    analogous to claims 2–18. 
    Id., col. 66,
    lines 1–62.
    Ariosa petitioned for inter partes review of claims 1–
    18 and 19–30. It argued that the claimed methods would
    have been obvious to a relevant skilled artisan in January
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.              7
    2010 in light of three prior-art references: Shoemaker,
    Dhallan, and Binladen.
    U.S. Patent Application No. 2008/0090239, filed in
    2008 by Shoemaker et al., discloses a method of determin-
    ing fetal aneuploidy by isolating fetal cells, not cell-free
    DNA. A maternal blood sample, known to include a very
    small number of fetal blood cells, is enriched for blood
    cells and then dispersed into wells, each well receiving at
    most one blood cell. Shoemaker ¶¶ 7, 8, 219. A polymer-
    ase chain reaction (PCR) technique is used to tag and
    amplify specific regions of chromosomes in those cells—
    regions being tested as well as control regions. 
    Id. ¶¶ 7,
    9. All amplified products are then pooled for sequencing.
    
    Id. ¶ 121.
    Non-maternal sequences are identified and
    used to distinguish wells containing fetal cells from those
    containing maternal cells. 
    Id. ¶ 138.
    For the wells that
    contain fetal cells, the ratio of maternal to non-maternal
    alleles is then compared: certain disparities will indicate
    the presence of extra copies of fetal chromosomes. 
    Id. ¶ 140.
        U.S. Patent No. 7,332,277, issued in 2003 to Dhallan,
    discloses a method of detecting fetal genetic disorders.
    Dhallan describes using a maternal blood sample to
    obtain a mixture of cell-free fetal and maternal DNA.
    ’277 patent, col. 31, lines 32–34. Specific DNA sequences
    are amplified and sequenced. 
    Id., col. 47,
    lines 38–39.
    After sequencing, maternal and fetal alleles are distin-
    guished, 
    id., col. 67,
    lines 28–34, the percentage of fetal
    DNA in the original sample is calculated, 
    id., col. 67,
    lines
    18–27, and the calculated ratio of fetal to maternal alleles
    is used to identify chromosomal abnormalities, 
    id., col. 68,
    lines 56–60.
    An article published in 2007 by Jonas Binladen et al.
    describes a study that involved tagging and sequencing
    DNA samples from multiple sources simultaneously. The
    study isolated DNA samples from thirteen species (hu-
    man, wolf, cheetah, lion, hippopotamus, zebra, mouse,
    8              ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    etc.) using a commercially available extraction kit, then
    amplified and indexed targeted sequences from those
    samples by methods of polymerase chain reaction that
    already were known. The amplified products were then
    pooled for sequencing, which was performed using a
    massively parallel sequencing machine.
    In its Petitions, Ariosa argued for obviousness based
    on combinations of Dhallan’s teachings about cell-free
    fetal DNA with Binladen’s indexing and sequencing
    techniques and Shoemaker’s method of determining
    aneuploidy. Specifically, Ariosa argued that “a scientist
    in this field would have known that Dhallan could be
    enhanced through use of the PCR amplification tech-
    niques utilizing sample indices and massively parallel
    sequencing of pooled samples as discussed in Binladen.”
    J.A. 208–09. It added “that a skilled artisan would have
    readily understood that Shoemaker’s methods for deter-
    mining the presence of fetal abnormalities could be car-
    ried out with the use of cell-free DNA described in
    Dhallan and the multiplexed detection techniques taught
    in Binladen.” J.A. 209.
    The Board instituted reviews under 35 U.S.C. § 314(a)
    upon finding a reasonable likelihood that the methods of
    the ’430 patent’s claims were unpatentable because they
    would have been obvious. But after receiving the Patent
    Owner’s Response and accompanying submissions, then
    Ariosa’s Reply and accompanying submissions, and then
    counsel’s oral arguments, the Board upheld all of the
    claims. The Board concluded that Ariosa did not carry its
    burden of showing that the claims would have been
    obvious. 35 U.S.C. § 316(e).
    The Board’s central point was that Ariosa’s Petitions
    were lacking because “virtually no effort [wa]s made to
    explain how or where the references differ from the chal-
    lenged claims, how one of ordinary skill in the art would
    go about combining their disparate elements, or what
    modifications one of ordinary skill in the art would neces-
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.              9
    sarily have made in order to combine the disparate ele-
    ments.” Ariosa, at *10. The Board discussed all three
    references—including, repeatedly, Shoemaker. 
    Id. at *5,
    6, 7, 9, 10, 11. It pointed to concessions of Ariosa’s ex-
    perts, Drs. Morton and Nussbaum, made in depositions
    after the Institution Decisions, that various modifications
    would have to be made to combine Dhallan and Binladen,
    including “that one ‘would do a different process to incor-
    porate the tags’ . . . and Binladen’s ‘tagging would not be
    the way that that was done, because the method of insert-
    ing the tag, the way it’s done now was not known at that
    time.’ ” 
    Id. at *9.
    The Board found unpersuasive Dr.
    Morton’s assertion that “ ‘one of ordinary skill . . . would
    be able to easily apply the teachings of Binladen to opti-
    mize the tags to decrease the error rate and increase the
    accuracy,’ ” given that Binladen’s tagging method dis-
    played a high error rate and detection of fetal aneuploidy
    requires “ ‘highly precise methods for quantification.’ ” 
    Id. (citing Dr.
    Morton’s declarations). The Board further
    noted that Dr. Morton, in her deposition, “was unable to
    recall describing ‘a synthesis of how to put [Shoemaker,
    Dhallan, and Binladen] together’ anywhere in her Decla-
    ration.” 
    Id. The Board
    summarized:
    What is lacking in the Petition and accompanying
    Declarations is an “articulated reason[ ] with some
    rational underpinning to support the legal conclu-
    sion of obviousness.” [In re] Kahn, 441 F.3d [977,
    988 (Fed. Cir. 2006)]. The inadequacy of the obvi-
    ousness analysis in the Petition and accompany-
    ing Declarations is readily apparent when the
    disparate elements of the references are scruti-
    nized closely, as in Patent Owner’s response, and
    we decline to search through the record and piece
    together those teachings that might support Peti-
    tioner’s position. Cf. DeSilva v. DiLeonardi, 
    181 F.3d 865
    , 866–67 (Fed. Cir. 1999) (“A brief must
    make all arguments accessible to the judges, ra-
    10                ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    ther than ask them to play archeologist with the
    record.”).
    Ariosa, at *10.
    At the end of its analysis, the Board addressed Ari-
    osa’s attempt, through a second declaration of Dr. Morton
    accompanying its Reply, to bolster the reliance placed in
    the Petitions on a brochure that describes indexing and
    massively parallel sequencing using the commercially
    available Illumina Genome Analyzer System (Exhibit
    1010). 
    Id. at *10–11.
    The Board stated:
    This testimony, in effect, replaces the tagging and
    sequencing techniques of Dhallan and Binladen
    with the Illumina indexing kit and sequencing
    platform, but neither Petitioner nor Dr. Morton
    explains why Exhibit 1010 could not have been
    presented as part of the asserted ground of un-
    patentability in the first instance with the Peti-
    tion.4 Therefore we accord this aspect of Dr.
    Morton’s testimony no weight.
    
    Id. at *11.
    In the footnote to that passage, the Board
    quoted the PTO regulation declaring that “[a] reply may
    only respond to arguments raised in the corresponding . . .
    patent owner response,” 37 C.F.R. § 42.23(b), and the
    related explanation that “[r]eply evidence . . . must be
    responsive and not merely new evidence that could have
    been presented earlier to support the movant’s motion,”
    Rules of Practice for Trials before the Patent Trial and
    Appeal Board, 77 Fed. Reg. 48,612, 48,620 (Aug. 14,
    2014). Ariosa, at *11 n.4.
    Ariosa appeals the Board’s determinations of nonobvi-
    ousness as to claims 1–18 and 19–30. The appeal is
    authorized by 35 U.S.C. § 319. This court has jurisdiction
    under 28 U.S.C. § 1295(a)(4)(A).
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.              11
    DISCUSSION
    This court reviews the Board’s ultimate determina-
    tions of obviousness de novo. Randall Mfg. v. Rea, 
    733 F.3d 1355
    , 1362 (Fed. Cir. 2013). It reviews for substan-
    tial evidence the underlying factual findings, which
    include findings as to the scope and content of the prior
    art, the differences between the prior art and the claimed
    invention, the level of ordinary skill in the art, the pres-
    ence or absence of a motivation to combine or modify with
    a reasonable expectation of success, and objective indicia
    of non-obviousness. See, e.g., id.; PAR Pharm., Inc. v.
    TWI Pharms., Inc., 
    773 F.3d 1186
    , 1196–97 (Fed. Cir.
    2014); Tri-Med, Inc. v. Stryker Corp., 
    608 F.3d 1333
    , 1341
    (Fed. Cir. 2010). A petitioner in an inter partes review
    has the burden of proving a claim’s invalidity by a pre-
    ponderance of the evidence. 35 U.S.C. § 316(e).
    A
    Ariosa’s principal challenge is to the Board’s treat-
    ment of Exhibit 1010, the Illumina brochure. Pointing to
    the Board’s language about Exhibit 1010, 
    quoted supra
    ,
    Ariosa argues that the Board erred in refusing to consider
    Exhibit 1010 for what it showed about the background
    knowledge that a skilled artisan would have possessed,
    particularly about DNA indexing, in January 2010. We
    agree with Ariosa up to a point: the Board’s language
    leaves open the distinct possibility that the Board incor-
    rectly limited its consideration of Exhibit 1010.
    The Board’s language on its face supports Ariosa’s in-
    terpretation of what the Board meant—that the Board
    was declining to consider Exhibit 1010, even as evidence
    of the background understanding of skilled artisans as of
    January 2010, simply because the brochure had not been
    identified at the petition stage as one of the pieces of prior
    art defining a combination for obviousness. If that is
    what the Board meant, the Board erred. Art can legiti-
    mately serve to document the knowledge that skilled
    artisans would bring to bear in reading the prior art
    12              ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    identified as producing obviousness. 
    Randall, 733 F.3d at 1362
    –63. Ariosa’s Petitions and opening declarations
    invoked Exhibit 1010 in that way.
    Ariosa included Exhibit 1010 in its Petitions as an ex-
    hibit to Dr. Nussbaum’s expert declaration. Dr. Nuss-
    baum, in discussing the state of the art of indexing and
    sequencing technology, stated that “as of 2008, indexed
    multiplexing was so widespread as a technique that the
    company Illumina, Inc. offered a commercially available
    kit for production and analysis of indexed libraries from
    different samples of origin,” and the indexed libraries
    could have been “analyzed on a commercially-available
    massively parallel sequencing platform sold by the same
    vendor.” J.A. 876. Ariosa’s second expert, Dr. Morton,
    also named the Illumina sequencing system when discuss-
    ing the state of the art of massively parallel sequencing,
    although she did not specifically refer to Exhibit 1010.
    The Petitions then cited portions of Dr. Nussbaum’s and
    Dr. Morton’s declarations for the same proposition—that
    “[m]assively parallel sequencing methods were in routine
    use by 2008.” J.A. 179. Given those references in the
    Petitions and supporting declarations, Exhibit 1010 had
    to be considered by the Board even though it was not one
    of the three pieces of prior art presented as the basis for
    obviousness.
    That the language of the Board regarding Exhibit
    1010 is readily susceptible of being read to rest on an
    incorrect legal proposition, by itself, does not require
    setting aside the Board’s decisions. We may affirm an
    agency ruling if we may reasonably discern that it fol-
    lowed a proper path, even if that path is less than perfect-
    ly clear. Bowman Transp., Inc. v. Arkansas-Best Freight
    System, Inc., 
    419 U.S. 281
    , 285–86 (1974). We also may
    affirm if an erroneous portion of an agency’s ruling is
    ultimately non-prejudicial, i.e., not material to the bot-
    tom-line result given other portions of the agency’s ruling.
    5 U.S.C. § 706; 28 U.S.C. § 2111; In re Chapman, 
    595 F.3d 1330
    , 1338 (Fed. Cir. 2010); In re Watts, 
    354 F.3d 1362
    ,
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.            13
    1369 (Fed. Cir. 2004). But we must not ourselves make
    factual and discretionary determinations that are for the
    agency to make. In re Lee, 
    277 F.3d 1338
    , 1342 (Fed. Cir.
    2002); ICC v. Bhd. of Locomotive Eng’rs, 
    482 U.S. 270
    , 283
    (1987); SEC v. Chenery Corp., 
    332 U.S. 194
    , 196–97
    (1947).
    Here, we cannot confidently discern whether the
    Board, in its consideration of Exhibit 1010, was actually
    relying on a legally proper ground rather than the errone-
    ous ground just noted. The Board might have been saying
    only that the development of the argument invoking
    Exhibit 1010 in the Petitions was not adequate. This
    court in Randall did not dispense with the need for par-
    ties to provide adequately developed explanations when
    relying on background knowledge based on cited art; the
    adequacy of the challenger’s explanation in that regard
    was unquestioned in 
    Randall. 733 F.3d at 1360
    . And a
    PTO regulation provides: “[t]he Board may exclude or give
    no weight to the evidence where a party has failed to state
    its relevance.” 37 C.F.R. § 42.104(b)(5). In the present
    case, other than stating that massively parallel sequenc-
    ing was known by 2008, the Petitions and supporting
    declarations say little about the relevance of Exhibit 1010,
    such as how a skilled artisan would have used what it
    showed about background knowledge in combining or
    modifying the prior-art references or how it tended to
    show that a skilled artisan would have had a reasonable
    expectation of success in achieving the suggested combi-
    nation and modification.
    Giving the inadequate-explanation reading to the
    Board’s statement about Exhibit 1010, though straining
    the words somewhat, would fit two related aspects of the
    Board’s decisions. First, the Board’s statement followed
    its quotation of Dr. Morton’s Reply declaration, which
    contains little if any more explanation of Exhibit 1010’s
    role than appeared in her original declaration: “[O]ne of
    ordinary skill in January 2010 would be motivated to
    index individual samples and pool them for sequencing to
    14              ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    maximize sequencing capacity and to minimize sequenc-
    ing cost. For example, the Illumina, Inc. product flyer
    from 2008 states, ‘[h]arnessing this sequencing power in a
    multiplexed fashion increases experimental throughput
    while reducing time and cost.’ ” Ariosa, at *11 (quoting
    J.A. 1485). Thus, while Dr. Morton’s Reply declaration
    identifies Exhibit 1010 as evincing a motivation to “index
    individual samples and pool them for sequencing,” it does
    not address whether Exhibit 1010 would have motivated a
    skilled artisan to replace the quantification methods of
    Dhallan, see, e.g., ’277 patent, col. 63, line 55 through col.
    65, line 28, with the technique of massively parallel
    sequencing described by Binladen. Second, at the heart of
    the Board’s analysis in the rest of its decisions is its
    finding that Ariosa provided inadequate explanation: the
    Petitions did not “explain how or where the references
    differ from the challenged claims, how one of ordinary
    skill in the art would go about combining their disparate
    elements, or what modifications one of ordinary skill in
    the art would necessarily have made in order to combine
    the disparate elements.” Ariosa, at *10.
    Yet the Board did not sufficiently articulate the fore-
    going grounds for its rejection of Ariosa’s reliance on
    Exhibit 1010 or other grounds independent of the incor-
    rect ground suggested by the Board’s language. Perhaps
    the Board could have done so. But it did not, and we
    cannot do so for the Board where, as here, the matter is
    not purely legal.
    We likewise are not prepared to find that the error we
    cannot rule out was non-prejudicial. We will not here
    draw our own conclusion about whether Exhibit 1010, if
    considered for what the Petitions (and supporting declara-
    tions) adequately presented about it, could have filled the
    explanatory gap that was the heart of the Board’s reason
    for finding Ariosa’s case unproved. Given the complexity
    of this area, and how seemingly small differences might
    be significant, we will not undertake to determine wheth-
    er a proper assessment of Exhibit 1010 should lead to a
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.           15
    reassessment of the explanatory gap. The Board is in a
    better position to do so. We will therefore vacate the
    decisions and remand.
    We do not direct the Board to take new evidence or,
    even, to accept new briefing. The Board may control its
    own proceedings, consistent with its governing statutes,
    regulations, and practice. 37 C.F.R. § 42.5(a). Those
    statutes, regulations, and practices embody expedition-
    and efficiency-based policies that the Board must consider
    in determining the scope of the remand proceedings.
    Congress generally directed that inter partes review
    proceedings be completed within one year of institution.
    35 U.S.C. § 316(a)(11). Reflecting that timing constraint,
    and the statutory goal of providing a relatively quick and
    low-cost alternative to litigation over validity, the PTO
    has established rules that, while necessarily respecting
    constitutional and statutory guarantees of procedural
    fairness, are designed generally to require that the par-
    ties make their cases in a very small number of filings—
    with the challenger obliged to make an adequate case in
    its Petition and the Reply limited to a true rebuttal role.
    37 C.F.R. §§ 42.104(b)(5), 42.23(b). Within this structure,
    even while providing for an estoppel effect on the chal-
    lenger, 35 U.S.C. § 315(e), Congress assigned to the
    challenger the burden of persuasion in the dispute, 
    id. § 316(e).
    That burden, together with the procedural rules
    impartially applied, means that, in some cases, a chal-
    lenge can fail even if different evidence and arguments
    might have led to success. We leave to the Board the
    determination of what remand proceedings are appropri-
    ate given the governing policies.
    B
    Ariosa also challenges the Board’s decision on a dis-
    tinct ground. The Board determined that teachings of
    Binladen and Dhallan could not be combined because
    “Binladen’s indexing (i.e., tagging) scheme could not be
    used with Dhallan’s restriction-digestible amplification
    16               ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.
    primers.” Ariosa, at *10. Ariosa argues that the Board
    erred in failing to consider some embodiments of Dhal-
    lan—those which do not require a restriction-enzyme
    digestible primer—embodiments that, they argue, could
    be combined with Binladen. The Board declined to con-
    sider those embodiments because the cited “portions of
    Dhallan were not identified or discussed in the Petition or
    the accompanying Declarations.” Ariosa, at *10. In any
    event, the Board added, Ariosa’s explanation was lacking
    even as to those portions. 
    Id. We see
    no error in the Board’s rejection of Ariosa’s re-
    liance, in its Reply submissions, on previously unidenti-
    fied portions of a prior-art reference to make a
    meaningfully distinct contention. Ariosa’s Petitions quote
    a portion of Dhallan that states: “Any method that pro-
    vides information on the sequence of a nucleic acid can be
    used . . . .” ’277 patent, col. 36, lines 6–19; see J.A. 189,
    215. The supporting declarations state that Dhallan
    teaches that the sequencing step can be performed using
    any method. J.A. 360–61 (quoting ’277 patent, col. 6, lines
    26–34); J.A. 919 (quoting ’277 patent, col. 36, lines 6–19).
    The Petitions and declarations, however, do no more than
    point to a generic statement in Dhallan that any sequenc-
    ing method can be used; they make no mention of how the
    choice of sequencing method influences the use of a re-
    striction-enzyme digestible primer, which occurs in the
    amplification step. ’277 patent, col. 36, lines 6–19. Not
    until Dr. Morton’s Reply declaration did Ariosa identify
    specific embodiments of Dhallan that do not use re-
    striction-enzyme digestible primers. J.A. 1479 (citing
    embodiments at ’277 patent, col. 11, line 61 through col.
    12, line 17; 
    id., col. 12,
    lines 40–47; 
    id., col. 13,
    line 66
    through col. 14, line 5; 
    id., col. 13,
    lines 36–42; 
    id., col. 14,
    lines 15–25).
    A governing regulation states that a Petition must
    identify “[t]he supporting evidence relied upon to support
    the challenge and the relevance of the evidence to the
    challenge raised, including identifying specific portions of
    ARIOSA DIAGNOSTICS   v. VERINATA HEALTH, INC.              17
    the evidence that support the challenge.” 37 C.F.R.
    § 42.104(b)(5). Further, “[t]he Board may exclude or give
    no weight to the evidence where a party has failed to state
    its relevance or to identify specific portions of the evidence
    that support the challenge” in the Petition. 
    Id. That regulation
    reflects the combination of efficiency and
    fairness interests also embodied in the regulation limiting
    Reply submissions to matter responsive to the Patent
    Owner’s Response. 
    Id. § 42.23(b).
    The Board must make
    judgments about whether a Petition identified the specific
    evidence relied on in a Reply and when a Reply contention
    crosses the line from the responsive to the new. The
    Board reasonably made those judgments here.
    C
    Ariosa challenges the adequacy of the Board’s consid-
    eration of Shoemaker—even though, as we have noted,
    the Board addressed Shoemaker throughout its analysis.
    We need not decide, however, whether there are any
    deficiencies in the Board’s consideration of arguments
    about Shoemaker made and supported in a timely manner
    by Ariosa. We are remanding the matter regardless. On
    remand, the Board may decide whether its treatment of
    Shoemaker should be left as is, supplemented, or revised.
    CONCLUSION
    For the foregoing reasons, we vacate the Board’s find-
    ing of nonobviousness and remand.
    No costs.
    VACATED AND REMANDED