Storer v. Clark , 860 F.3d 1340 ( 2017 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    RICHARD STORER, GILLES GOSSELIN, JEAN-
    PIERRE SOMMADOSSI, PAOLA LACOLLA,
    Appellants
    v.
    JEREMY CLARK,
    Appellee
    UNITED STATES,
    Intervenor
    ______________________
    2015-1802
    ______________________
    Appeal from the United States Patent and Trademark
    Office, Patent Trial and Appeal Board in No. 105,981.
    ______________________
    Decided: June 21, 2017
    ______________________
    GREGORY A. CASTANIAS, Jones Day, Washington, DC,
    argued for appellants. Also represented by JENNIFER
    LORAINE SWIZE; ANTHONY M. INSOGNA, JOHN DAVID
    KINTON, San Diego, CA; THOMAS EUGENE FRIEBEL, New
    York, NY; CALVIN GRIFFITH, Cleveland, OH.
    FRANK SCHERKENBACH, Fish & Richardson PC, Bos-
    ton, MA argued for appellee. Also represented by
    2                                           STORER   v. CLARK
    JONATHAN ELLIOT SINGER, CRAIG E. COUNTRYMAN, W.
    CHAD SHEAR, San Diego, CA.
    JOSEPH FORREST BUSA, Appellate Staff, Civil Division,
    United States Department of Justice, Washington, DC,
    argued for intervenor. Also represented BY MARK R.
    FREEMAN, BENJAMIN C. MIZER; THOMAS W. KRAUSE, Office
    of the Solicitor, United States Patent and Trademark
    Office, Alexandria, VA.
    ______________________
    Before PROST, Chief Judge, NEWMAN, and DYK, Circuit
    Judges.
    NEWMAN, Circuit Judge.
    This patent interference contest involves methods of
    treating hepatitis C by administering compounds having
    a specific chemical and stereochemical structure, based on
    the following foundation formula of a five-membered ring
    having the fluorine substituent in the 2´(down) position:
    Storer Br. at 8. The priority decision was based on ena-
    blement of this product. The interference was declared
    between an issued patent (Storer et al.) and a pending
    application (Clark), both of which were filed before the
    effective date of the America Invents Act, the statute that
    abolished the first-to-invent interference rule in favor of a
    STORER   v. CLARK                                          3
    first-to-file rule. By the terms of the Act, § 3(n)(2), the
    prior, first-to-invent, law applies to this interference.
    To establish priority, Storer relied on the disclosure in
    the provisional specification from which priority was
    claimed for conception and constructive reduction to
    practice. In its joint decision on Clark’s motion to deny
    Storer the benefit of the provisional application and on
    Clark’s motion to invalidate Storer’s claims on the
    grounds of lack of enablement and written description, 1
    the Patent Trial and Appeal Board (PTAB or “Board”)
    held that Storer’s provisional application was not ena-
    bling for the count of the interference, and on that ground
    the PTAB entered judgment granting priority to Clark. 2
    Storer appeals that judgment and the underlying decision
    on Clark’s motions.
    We take note that Storer initially filed in the District
    of Delaware, seeking review of the Board’s decision under
    
    35 U.S.C. § 146
    . The district court dismissed the case,
    Idenix Pharmaceuticals. LLC v. Gilead Pharmasset LLC,
    
    2016 WL 6804915
    , at *1 (D. Del. Nov. 16, 2016), based on
    this court’s ruling in Biogen MA, Inc. v. Japanese Founda-
    tion for Cancer Research, 
    785 F.3d 648
     (Fed. Cir. 2015),
    that the America Invents Act eliminated the option of
    district court review under Section 146 for interferences
    declared after September 15, 2012. Although Storer says
    that Biogen was incorrectly decided, that decision is
    binding on this panel. Storer’s appeal of the district
    court’s dismissal has been stayed pending the outcome of
    1   Decision on Motions – Bd.R. 125, Clark v. Storer,
    Interference No. 105,981, (P.T.A.B. Jan. 16, 2015), Doc
    No. 687 (“Bd. Op.”).
    2 Clark v. Storer, Interference No. 105,981, 
    2015 WL 1325503
     (P.T.A.B. Mar. 23, 2015).
    4                                          STORER   v. CLARK
    this appeal. Order, Idenix Pharm. LLC v. Gilead Phar-
    masset LLC, No. 17-1369 (Fed. Cir. Feb. 16, 2017).
    BACKGROUND
    Inventors Richard Storer et al. were issued U.S. Pa-
    tent No. 7,608,600 (“the ‘600 Patent”), on a final applica-
    tion filed on June 27, 2003. The patent is assigned to
    Idenix Pharmaceuticals. In the interference proceeding,
    Storer was initially declared the senior party based on the
    June 28, 2002 filing date of provisional application No.
    60/392,350 (called “the S1 application” by the Board).
    Clark’s Application No. 11/854,218, assigned to Gilead
    Pharmasset, was filed September 12, 2007, with priority
    claimed to a provisional application filed on May 30, 2003.
    Clark moved to deny Storer the priority date of the S1
    application and to invalidate Storer’s claims, arguing that
    the S1 application did not enable compounds having the
    2´F(down) substituent. Storer argued that these com-
    pounds were generically disclosed in the S1 application,
    and were readily obtained based on the disclosure in the
    S1 provisional and the prior art. The Board did not agree,
    and by withdrawing entitlement to the provisional’s filing
    date, the Board awarded priority to Clark. Storer now
    appeals that decision.
    DISCUSSION
    The Interfering Claims
    Storer and Clark were investigating the treatment of
    hepatitis C using modified nucleoside compounds, includ-
    ing certain heterocyclic compounds having a fluorine
    substituent in the 2´ position. The PTAB identified the
    interfering subject matter, and selected claims for purpos-
    es of determining priority. From the Storer patent, the
    Board selected claim 1:
    1. A method for the treatment of a host infected
    with a hepatitis C virus, comprising administer-
    STORER   v. CLARK                                         5
    ing to the host infected with a hepatitis C virus an
    effective amount of a compound having the formu-
    la:
    or a pharmaceutically acceptable salt thereof,
    wherein:
    R1 is H; mono-, di- or triphosphate; acyl; an amino
    acid ester; a carbohydrate; a peptide;
    or a pharmaceutically acceptable leaving group
    which when administered in vivo provides a com-
    pound wherein R1 is H or phosphate;
    R2 is H; acyl; an amino acid ester; a carbohydrate;
    a peptide; or a pharmaceutically acceptable leav-
    ing group which when administered in vivo pro-
    vides a compound wherein R2 is H;
    Base* is selected from the group consisting of ad-
    enine,    N6-alkylpurine,     N6-acylpurine,   N6-
    benzylpurine, N6-halopurine, N6-vinylpurine, N6-
    acetylenic     purine,    N6-acyl    purine,   N6-
    hydroxyalkylpurine, N6-alkylamino-purine, N6-
    thioalkyl purine, N2-alkylpurine, N2-alkyl-6-
    thiopurine, thymine, cytosine, 5-fluorocytosine, 5-
    methylcytosine, 6-azapyrimidine, 6-azacytosine, 2-
    and/or 4-mercaptopyrimidine, uracil, 5-halouracil,
    5-fluorouracil,       C5-alkylpyrimidine,       C5-
    benzylpyrimidine,       C5-halopyrimidine,     C5-
    vinylpyrimidine, C -acetylenic pyrimidine, C -acyl
    5                        5
    6                                          STORER   v. CLARK
    pyrimidine,     C5-hydroxyalkyl     purine,     C5-
    amidopyrimidine,       C5-cyanopyrimidine,      C5-
    iodopyrimidine, C -iodo-pyrimidine, C -Br-vinyl
    6                     5
    pyrimidine,       C6-Br-vinylpyrimidine,        C5-
    nitropyrimidine,     C -amino-pyrimidine,
    6                       N2-
    alkylpurine, N2-alkyl-6-thiopurine, 5-azacytidinyl,
    5-azauracilyl, triazolopyridinyl, imidazolopyridi-
    nyl,   pyrrolopyrimidinyl,    pyrazolopyrimidinyl,
    guanine, hypoxanthine, 2,6-diaminopurine, and 6-
    choropurine;
    R12 is C(Y3)3; and
    Y3 is independently H or F.
    From the Clark application, the Board selected claim 164:
    164. A method for the treatment of hepatitis C in-
    fection, which comprises:
    administering to a mammal in need thereof an an-
    tivirally effective amount of a (2ˊR)-2ˊ-deoxy-2ˊ-
    fluoro-2ˊ-C-methyl nucleoside (β-D or β-L) or its
    pharmaceutically acceptable salt of the structure:
    wherein R1 and R7 are independently H, a mono-
    phosphate, a diphosphate, a triphosphate, a H-
    phosphonate, an alkyl, an alkyl sulfonyl, or an ar-
    ylalkyl sulfonyl; and R4 is NH2 or OH.
    STORER   v. CLARK                                         7
    The parties agree that the only question focuses on
    whether the Storer S1 provisional together with the prior
    art enabled compounds having a 2´F(down) substituent.
    Enablement
    Enablement is relevant for validity and to the issue of
    whether the provisional application is a constructive
    reduction to practice. “Constructive reduction to practice
    means a described and enabled anticipation under 35
    U.S.C. 102(g)(1), in a patent application of the subject
    matter of a count.” 
    37 C.F.R. § 41.201
    . “When a party to
    an interference seeks the benefit of an earlier-filed United
    States patent application, the earlier application must
    meet the requirements of 
    35 U.S.C. § 120
     and 
    35 U.S.C. § 112
     ¶ 1 for the subject matter of the count.” Hyatt v.
    Boone, 
    146 F.3d 1348
    , 1352 (Fed. Cir. 1998) (footnotes
    omitted). Section 112 ¶ 1 requires:
    The specification shall contain a written descrip-
    tion of the invention, and of the manner and pro-
    cess of making and using it, in such full, clear,
    concise, and exact terms as to enable any person
    skilled in the art to which it pertains, or with
    which it is most nearly connected, to make and
    use the same, and shall set forth the best mode
    contemplated by the inventor of carrying out his
    invention.
    
    35 U.S.C. § 112
    , para. 1. 3 Therefore, when the issue is
    priority based on the content of the specification, “[t]he
    earlier application must contain a written description of
    the subject matter of the interference count, and must
    meet the enablement requirement.” Hyatt, 
    146 F.3d at 1352
    .
    3     This section is now § 112(a).
    8                                             STORER   v. CLARK
    Enablement is a matter of law, and is reviewed with-
    out deference; however, the factual underpinnings of
    enablement are reviewed for support by substantial
    evidence on the entirety of the PTO record. Microsoft
    Corp. v. Proxyconn, Inc., 
    789 F.3d 1292
    , 1297 (Fed. Cir.
    2015). To establish enablement of a claim whereby new
    chemical compounds are provided for use to treat disease,
    the application must enable production or synthesis of the
    new compounds. See In re Brebner, 
    455 F.2d 1402
    , 1404
    (C.C.P.A. 1972) (“A method of making starting materials
    not known in the art must be set forth in order to comply
    with the enablement requirement.”).
    The Board held that the S1 provisional, taken togeth-
    er with the prior art, did not enable the specific com-
    pounds having the identified structure. Storer argued,
    and repeats on appeal, that a person of ordinary skill
    would have been able to make this class of compounds,
    having the requisite stereochemistry, based on infor-
    mation in the S1 provisional application and the prior art.
    “The enablement requirement is met where one skilled in
    the art, having read the specification, could practice the
    invention without ‘undue experimentation.’” Streck, Inc.
    v. Research & Diagnostic Sys., Inc., 
    665 F.3d 1269
    , 1288
    (Fed. Cir. 2012) (quoting ALZA Corp. v. Andrx Pharm.,
    LLC, 
    603 F.3d 935
    , 940 (Fed. Cir. 2010)).
    “Whether undue experimentation is required ‘is not a
    single, simple factual determination, but rather is a
    conclusion reached by weighing many factual considera-
    tions.’” 
    Id.
     As summarized in In re Wands, 
    858 F.2d 731
    ,
    737 (Fed. Cir. 1988), relevant factors may “include (1) the
    quantity of experimentation necessary, (2) the amount of
    direction or guidance presented, (3) the presence or ab-
    sence of working examples, (4) the nature of the inven-
    tion, (5) the state of the prior art, (6) the relative skill of
    those in the art, (7) the predictability or unpredictability
    of the art, and (8) the breadth of the claims.”
    STORER   v. CLARK                                           9
    The Board determined that the claimed compounds
    having a 2´F(down) substituent were not enabled in
    Storer’s S1 provisional application, in that undue experi-
    mentation would be required to produce this structure.
    The Board analyzed the disclosure in terms of the eviden-
    tiary factors set forth in Wands.
    Storer does not dispute the Board’s findings as to the
    third, fourth, fifth, sixth, and eighth Wands factors, but
    argues that these factors are not dispositive of enable-
    ment. For the third Wands factor—the presence or ab-
    sence of working examples—Storer does not dispute that
    the S1 provisional contains no specific examples of syn-
    thesis of compounds having the fluoro substituent in the
    2´(down) position. Bd. Op. at 24.
    For the fourth Wands factor—the nature of the inven-
    tion—the Board found that:
    Count 1 is best characterized as the administra-
    tion of a genus of nucleosides used in the treat-
    ment of viruses, particularly those of the family
    Flaviviridae (which includes HBV and HCV). We
    also find that, as of the time of filing of the S1 ap-
    plication, although organic fluoridation mecha-
    nisms were generally well-known in the art a 2ˊ-
    fluoro-2ˊ-methyl nucleoside with the fluoro sub-
    stituent in the “down” position had not yet been
    synthesized.
    Id. at 25 (footnote omitted). Storer does not dispute this
    finding.
    For the fifth Wands factor—the state of the prior
    art—the Board found that:
    although DAST [N,N-diethylamino-sulfur trifluo-
    ride] was well-known in the prior art as fluoridat-
    ing agent for nucleosides and nucleoside analogs,
    the prior art did not teach, or explicitly suggest,
    the use of DAST in the fluoridation of a tertiary
    10                                           STORER   v. CLARK
    alcohol to convert a tertiary alcohol at a nucleo-
    side 2ˊ position to a tertiary fluorine at the nucle-
    oside 2ˊ “down” position. We further find that,
    although organic fluoridation techniques were
    well-known in the art at the time the S1 applica-
    tion was filed, fluoridation of tertiary alcohols to
    produce a 2ˊ “down” tertiary fluorine was not
    taught or suggested by the prior art.
    Id. at 29. Storer does not dispute this finding.
    With respect to the sixth Wands factor, the Board par-
    ticularly relied on Wands factors 1, 2, 3, 4, and 7 and
    found that “the parties largely agree that the level of skill
    in the art is very high” and that
    a person possessing the ordinary level of skill in
    this art, as of the time of the invention, would
    hold a doctoral degree in the field of organic, syn-
    thetic, or medicinal chemistry with at least a
    year’s experience in the field of nucleoside synthe-
    sis or relevant drug discovery.
    Id. at 29–30. The Board also found that neither party
    argued the eighth Wands factor regarding the breadth of
    the claims. Id. at 34 n.64. These findings are not disput-
    ed.
    The Board summarized the evidence and findings on
    which it concluded that undue experimentation would be
    needed to produce the designated molecule:
    (1) synthesis of a 2ˊ-fluoro-2ˊ-methyl nucleoside
    with the fluoro moiety in the “down” position re-
    quired at least two years of a high-priority exper-
    imentation by persons skilled in the art, including
    multiple consultations with experts at the top of
    their fields and additional formal training;
    STORER   v. CLARK                                           11
    (2) the S1 application provides little in the way of
    direction or guidance as to how to synthesize such
    a compound;
    (3) the S1 application provides no explicit example
    of a 2ˊ-fluoro-2ˊ-methyl nucleoside, nor was an ex-
    ample provided by the relevant art as of the S1
    application’s filing date;
    (4) the invention is characterized as the admin-
    istration of a genus of nucleosides used in the
    treatment of viruses, particularly those of the
    family Flaviviridae (which includes HBV and
    HCV) and an embodiment of the count requires a
    2ˊ-fluoro(“down”) 2ˊ-methyl nucleoside;
    (5) although organic fluoridation techniques were
    well-known in the art at the time the S1 applica-
    tion was filed, fluoridation of tertiary alcohols to
    produce a 2ˊ “down” tertiary fluorine was not
    taught or suggested by the prior art;
    (6) the level of skill in the art was highly sophisti-
    cated: a person possessing the ordinary level of
    skill in this art, as of the time of invention, would
    hold a doctoral degree in the field of organic, syn-
    thetic, or medicinal chemistry with at least a
    year’s experience in the field of nucleoside synthe-
    sis or relevant drug discovery; and
    (7) the art, at least with respect to fluoridation of
    tertiary alcohols to produce a tertiary fluorine in
    the 2ˊ “down” position, was highly unpredictable.
    We therefore find that Wands factors 1, 2, 3, 5,
    and 7 strongly indicate that a person skilled in the
    art would not arrive at the claimed invention
    without undue experimentation.
    Id. at 34–35.
    12                                         STORER   v. CLARK
    Based on these findings, the Board concluded that the
    interference subject matter was not enabled by Storer’s
    S1 provisional application.
    Argument on Appeal
    Storer argues that the S1 provisional application “per-
    formed the substantial step of disclosing the precise
    chemical structure of the target compound.” Storer Br. at
    47. Storer does not, however, identify any specific struc-
    ture having the 2´F(down) substituent. The pages of the
    S1 provisional cited by Storer include generic structures,
    and Clark does not dispute that the “target compounds,”
    as the Board calls the 2´F(down) compounds, are generi-
    cally included in the S1 provisional application’s generic
    formulas.
    Storer states that the prior art contains “a well-known
    precursor compound that is only one step away from the
    target compound.” Id. at 8. Storer states that this pre-
    cursor is “Matsuda Compound 17,” citing Akira Matsuda
    et al., Alkyl Addition Reaction of Pyrimidine 2´-
    Ketonucleosides: Synthesis of 2´-Branched-Chain Sugar
    Pyrimidine Nucleosides (Nucleosides and Nucleotides
    LXXXI), 36 CHEMICAL & PHARMACEUTICAL BULL., no. 3,
    Mar. 1988, at 945.
    Matsuda Compound 17 is presented in Storer’s brief
    as
    STORER   v. CLARK                                     13
    Storer Br. at 12. Matsuda Compound 17 contains a
    methyl group in the 2´(down) position, and Storer states
    that Matsuda Compound 17 is readily converted into the
    target compound by known methods to produce the de-
    sired stereochemistry. Matsuda Compound 17 is not
    mentioned in the S1 provisional, but Storer argues that
    the precursor to Matsuda Compound 17 is in the S1
    provisional, “as is that precursor’s conversion to the
    Matsuda compound,” Id. at 48 n.16. Storer states that the
    precursor “is only two steps away from the desired 2´-
    methyl ‘up’, 2´-fluoro ‘down’ configuration,” and “each
    scheme discloses how to modify the 2´-keto precursor to
    obtain” Matsuda Compound 17. Id. at 9.
    Thus Storer argues that the Matsuda reference, to-
    gether with the information in the S1 provisional, enable
    synthesis of 2´F(down) compounds. Storer states that
    Schemes 3, 4 and 8 in the S1 provisional each describes a
    “2´-keto precursor, i.e., a compound with ‘=O’ at the 2´
    position,” and that this is the path to the 2´F(down)
    molecule. Id. at 9. The three schemes from the S1 provi-
    sional are:
    14                           STORER   v. CLARK
    Storer Prov. Appl. at 119.
    STORER   v. CLARK                                           15
    Id. at 120.
    Id. at 1948.
    These three schemes indeed show a compound with
    =O at the 2´ position, but none shows conversion to
    Matsuda Compound 17 or further conversion to the
    2´F(down) analog. Clark points out that each scheme
    produces compounds with the opposite spatial arrange-
    ment from Matsuda Compound 17, for in Matsuda Com-
    pound 17 the 2´-OH is “up,” whereas in Scheme 4 the 2´-
    OH is “down.” Clark Br. at 5.
    Storer does not dispute the chemical facts, but argues
    that the difference between Matsuda 17 and the provi-
    sional synthesis schemes does not negate enablement
    because
    if the alkylation reagent is methyl lithium (MeLi)
    or methyl Grignard (MeMgBr) for methylation as
    taught by the specification, one of ordinary skill in
    the art will obtain products with the orientation
    (i.e., “stereochemistry”) of the OH and methyl
    groups needed to synthesize the target compound
    using DAST or Deoxo-Fluor. Furthermore, the
    prior art teaches how to control the stereochemis-
    try of these groups.
    16                                          STORER   v. CLARK
    Storer Br. at 9-10 n.5. Although the S1 provisional
    schemes show products with the opposite stereochemistry,
    Storer argues that a person of ordinary skill could make
    Matsuda Compound 17 employing these schemes. Storer
    argues that “a skilled artisan would have recognized that
    Matsuda Compound 17 was a viable precursor,” id. at 48,
    and that: “With knowledge of those structures, the hypo-
    thetical person would have known to use a common, one-
    step synthesis to modify the well-known precursor to
    obtain the target compound.” Id. Storer states that
    “simply by looking at the chemical structure of the target
    compound disclosed by Idenix, a person of ordinary skill
    would know to use a fluorination reagent,” id., and “DAST
    and Deoxo-Fluor were the most well-known fluorinating
    reagents at the time for one-step fluorination reactions.”
    Id. at 49. Storer argues that Matsuda provides any
    necessary information not in the S1 provisional.
    Clark responds that these are overstatements, for nei-
    ther Matsuda Compound 17 nor any compound with the
    2´F(down) structure is mentioned in the Storer S1 provi-
    sional. Clark points out that none of the several synthetic
    schemes in Storer’s provisional application shows conver-
    sion of any precursor into Matsuda Compound 17. Clark
    states that Storer’s synthetic schemes only disclose com-
    pounds with the “wrong stereochemistry.” Clark Br. at
    37.
    The Board agreed with Clark’s position, and held that
    the S1 provisional’s description of the 2´-keto precursor, in
    combination with the Matsuda reference, was insufficient
    to enable and thereby to establish possession of the
    2´F(down) methyl(up) compound of claim 1 before Clark’s
    priority date. The Board stated, correctly, that for new
    chemical compounds the specification must provide suffi-
    cient guidance that undue experimentation is not re-
    quired to obtain the new compounds.
    STORER   v. CLARK                                            17
    ANALYSIS
    The boundary between a teaching sufficient to enable
    a person of ordinary skill in the field, and the need for
    undue experimentation, varies with the complexity of the
    science. Knowledge of the prior art is presumed, as well
    as skill in the field of the invention. The specification
    need not recite textbook science, but it must be more than
    an invitation for further research. Genentech, Inc. v. Novo
    Nordisk A/S, 
    108 F.3d 1361
    , 1366 (Fed. Cir. 1997).
    In Genentech the patentee argued that the prior art
    taught a method that could be used to produce a claimed
    human growth hormone product, compensating for lack of
    detail in the specification. The patentee argued that it
    did not need to include information in the prior art. This
    court agreed, but stressed the need to assure enablement
    of the novel aspects of the invention:
    It is true . . . that a specification need not disclose
    what is well known in the art. See, e.g., Hybritech
    Inc. v. Monoclonal Antibodies, Inc., 
    802 F.2d 1367
    ,
    1385 (Fed. Cir. 1986). However, . . . . [i]t is the
    specification, not the knowledge of one skilled in
    the art, that must supply the novel aspects of an
    invention in order to constitute adequate enable-
    ment.
    Genentech, 
    108 F.3d at 1366
    .
    The Storer provisional specification does not describe
    synthesis of the 2´F(down) target compounds. The ques-
    tion devolves to the adequacy of the disclosure in the
    provisional of general schemes for synthesizing these
    general classes of modified nucleosides, taken with the
    knowledge of the art. The S1 provisional discloses two
    general approaches. Provisional schemes 3 and 8 modify
    the sugar portion of the target compound and then add
    the base portion, as the provisional application calls the
    18                                           STORER   v. CLARK
    “Glycosylation of the nucleobase with an appropriately
    modified sugar.” Storer Prov. Appl. at 117.
    Provisional scheme 4 shows modifying a compound
    with the base already attached, to achieve the desired
    structure. The provisional calls this “Modification of a
    pre-formed nucleoside.” Id. at 119. The Board observed
    that none of the approaches in the provisional proceeds
    through a compound like Matsuda Compound 17, or
    suggests how Matsuda 17 may be converted into the
    target 2´F(down) compounds. The Board found that the
    Storer provisional does not exemplify such a reaction, or
    lead a person of ordinary skill to perform it. The Board
    also observed that the S1 provisional schemes produce
    compounds with opposite spatial arrangement from
    Matsuda Compound 17.
    On review, we conclude that substantial evidence
    supports the Board’s findings that the synthetic schemes
    in Storer’s provisional application do not teach or suggest
    conversion of any precursor into the 2´F(down) structure,
    and that the Matsuda synthesis of a corresponding 2´-
    methyl (down), 2´-hydroxyl (up) structure does not enable
    a person of ordinary skill to produce the target compounds
    without undue experimentation.
    Wands factor 7, the predictability or unpredictability
    of the art, appears to be particularly relevant. Although
    Storer states that this is predictable chemistry, and
    therefore that detailed specific examples are not neces-
    sary, the Board’s findings are in accord with the record.
    The Board found:
    Having reviewed the parties’ arguments, and the
    proffered evidence, we find that the art, with re-
    spect to fluoridation of tertiary alcohols, was high-
    ly unpredictable, as evidenced by Idenix’s
    repeatedly unsuccessful attempts to synthesize its
    high-priority target nucleoside, and as further
    STORER   v. CLARK                                        19
    evinced by the statements of Dr. Coe and Dr.
    Storer.
    Bd. Op. at 33–34. Regarding Dr. Coe’s and Dr. Storer’s
    statements, the Board stated:
    Dr. Paul Coe, an expert in organofluorines, ex-
    pressed skepticism regarding the use of DAST;
    and Dr. Richard Storer stated that “[a] lot of
    things which look simple on paper in related sys-
    tems have been tried and don’t work in this series.
    Having to make the tertiary fluoride is very dif-
    ferent to [sic] having to make secondary.”
    Id. at 31 (quoting from the record). The Board also re-
    ferred to evidence presented on behalf of Clark that
    “attempted fluorination reactions (including those involv-
    ing DAST) could fail, resulting in unfluorinated elimina-
    tion and/or rearrangement products, or products with
    incorrect stereochemistry.” Id. at 30.
    Even on Storer’s position that a person skilled in this
    science would have started with Matsuda Compound 17,
    Storer has not shown that the critical stereochemical
    result would predictably ensue, although the reaction had
    never been performed. The Board received evidence of
    side reactions and the skepticism of experts. The Board
    received evidence that Storer and his team had difficulty
    and failures in synthesizing the target compound, as well
    as evidence that Clark and his team were more readily
    successful using apparently the same method.           The
    Board’s finding that the chemistry was unpredictable is in
    accord with the evidence.
    The first Wands factor is concerned with “undue” ex-
    perimentation, and recognizes that what is “undue” of
    itself depends on the subject matter and skill. The Board
    discussed the amount of experimentation needed to
    produce the claimed compounds, and found that:
    20                                           STORER   v. CLARK
    a high amount of experimentation is necessary to
    synthesize a 2´-fluoro-2´-methyl nucleoside with
    the fluoro moiety in the “down” position, requiring
    at least two years of a high priority experimenta-
    tion by persons skilled in the art, including multi-
    ple consultations with experts at the top of the
    fields and additional formal training.
    Id. at 19. The Board discussed the evidence showing
    Storer’s continuing research after the S1 provisional was
    filed, including the following findings:
    •   “Idenix’s research team in Montpellier,
    France, repeatedly attempted without success
    to    synthesize   a    2´-methyl(“up”)   2´-
    fluoro(“down”) nucleoside during the interval
    between December 2002 and September
    2004.” Id. at 14.
    •   “Idenix scientists also corresponded with con-
    sultants Dr. George Fleet and Dr. Paul Coe in
    an attempt to effect a synthesis of the desired
    compound.” Id. at 14.
    •   “Idenix personnel also attended a ‘Scientific
    Update Course’ entitled ‘Making and Using
    Fluoroorganic Molecules’ in April, 2003, and
    submitted a report summarizing the course
    content.” Id. at 15.
    •   “Dr. Jean-François Griffon, leader of the
    Montpellier group, testified that he attempted
    at least seven different synthetic schemes, in-
    cluding several suggested by Dr. Coe, and in
    some cases employing DAST, without suc-
    cess.” Id. at 15.
    •   “[A]ttempts by the Montpellier team to use
    DAST in the synthesis of a 2´-fluoro-2´-methyl
    nucleoside produced similar failures.” Id. at
    16.
    STORER   v. CLARK                                           21
    •     “With respect to the testimony of Jingyang
    Wang who allegedly synthesized the desired
    compound in a single attempt in January,
    2015, at Idenix’s research facility in Cam-
    bridge, Massachusetts, we note that, prior to
    beginning her synthesis, Ms. Wang had re-
    ceived the reports from the Montpellier group
    as well as intermediate compositions synthe-
    sized at Montpellier. Consequently, Ms. Wang
    was not, as Storer seems to suggest, attempt-
    ing synthesis of a 2´-fluoro-2´methyl nucleo-
    side ab initio, but rather had the hindsight
    benefit of the Montpellier group’s efforts.” Id.
    at 17 (citations to the record omitted).
    Storer argues that the Board failed to address the fact
    that Clark readily synthesized a target compound in a
    single step from Matsuda Compound 17. The Board
    acknowledged Storer’s argument that it was “informative
    that Clark, a chemist without a Ph.D., was allegedly able
    to make a 2ˊ-methyl (up) 2ˊ-fluoro (down) nucleoside in
    just a few months using DAST.” Id. at 13. Storer states
    that “Clark’s experiments directly contradict the Board’s
    reliance on the allegedly failed attempts of Griffon.”
    Storer Br. at 55. There was evidence that Clark used a
    method similar to that attempted by Griffon on the Storer
    team, and that Clark succeeded where Griffon apparently
    failed. Storer stated to the Board that Griffon actually
    produced the target compound, but was not able to purify
    it from the reaction mixture.
    The Board found, on consideration of the entire rec-
    ord, that a person of ordinary skill, with the disclosure in
    the provisional application and knowledge of the prior art,
    would not have been led to make the target compound,
    and could not do so without undue experimentation. The
    Board received evidence that successful fluorination
    reactions of the desired stereochemistry had not been
    reported for structurally similar compounds.
    22                                         STORER   v. CLARK
    We conclude that substantial evidence supports the
    Board’s finding that “a high amount of experimentation is
    necessary to synthesize” the target compound. The record
    before the Board showed sufficient variability and unpre-
    dictability to support the Board’s conclusion that Storer’s
    provisional application did not enable the interference
    subject matter. The Board’s decision is affirmed.
    AFFIRMED