Bayer Pharma Ag v. Watson Laboratories, Inc. , 874 F.3d 1316 ( 2017 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    BAYER PHARMA AG, BAYER INTELLECTUAL
    PROPERTY GMBH, BAYER HEALTHCARE
    PHARMACEUTICALS, INC.,
    Plaintiffs-Appellees
    v.
    WATSON LABORATORIES, INC., ACTAVIS
    PHARMA, INC.,
    Defendants-Appellants
    ______________________
    2016-2169
    ______________________
    Appeal from the United States District Court for the
    District of Delaware in No. 1:12-cv-00517-GMS, Judge
    Gregory M. Sleet.
    ______________________
    Decided: November 1, 2017
    ______________________
    DAVID I. BERL, Williams & Connolly LLP, Washing-
    ton, DC, argued for plaintiffs-appellees. Also represented
    by BRUCE GENDERSON, DOV PHILIP GROSSMAN, AARON P.
    MAURER, ADAM LAWRENCE PERLMAN, THOMAS S.
    FLETCHER, GALINA I. FOMENKOVA.
    WILLIAM M. JAY, Goodwin Procter LLP, Washington,
    DC, argued for defendants-appellants. Also represented
    2                     BAYER PHARMA AG   v. WATSON LABS., INC.
    by ELIZABETH HOLLAND, ROBERT V. CERWINSKI, BRIAN
    ROBINSON, New York, NY; DAVID ZIMMER, Boston, MA.
    ______________________
    Before LOURIE, MOORE, and O’MALLEY, Circuit Judges.
    MOORE, Circuit Judge.
    Watson Laboratories, Inc. appeals the District of
    Delaware’s final judgment holding Watson failed to prove
    by clear and convincing evidence that claims 9 and 11 of
    U.S. Patent No. 8,613,950 (“the ’950 patent”) would have
    been obvious. We hold the district court clearly erred in
    finding a skilled artisan would not have been motivated to
    use the claim elements. Considering the district court’s
    clear error together with the remainder of its fact find-
    ings, we conclude that claims 9 and 11 of the ’950 patent
    would have been obvious. We therefore reverse.
    BACKGROUND
    In 2003, the Food & Drug Administration (“FDA”)
    granted Bayer 1 approval to market vardenafil hydrochlo-
    ride trihydrate to treat erectile dysfunction (“ED”) under
    the name Levitra. Vardenafil belongs to a class of ED
    drugs called phosphodiesterase inhibitors. When the FDA
    approved Levitra, two other phosphodiesterase inhibitors
    were already on the market: Pfizer launched sildenafil
    under the name Viagra in 1998, and Eli Lilly launched
    tadalafil under the name Cialis in 2003. Levitra, Viagra,
    and Cialis are each formulated as immediate-release
    tablets that are swallowed whole.
    1   For purposes of this opinion, Bayer Pharma AG,
    Bayer Intellectual Property GmbH, and Bayer Healthcare
    Pharmaceuticals, Inc. are referred to as “Bayer” both
    collectively and individually.
    BAYER PHARMA AG   v. WATSON LABS., INC.                   3
    The ’950 patent issued on December 24, 2013. It
    claims priority to March 1, 2005 and lists Bayer as its
    assignee. It is directed to a formulation of vardenafil “in
    the form of an uncoated tablet which disintegrates rapidly
    in the mouth,” commonly referred to as an oral disinte-
    grating tablet (“ODT”). See ’950 patent at claim 8. Bayer
    markets a commercial embodiment of the ’950 patent,
    vardenafil ODT, under the name Staxyn.
    Watson filed an Abbreviated New Drug Application
    (“ANDA”) with the FDA seeking approval to market a
    generic version of Staxyn. Bayer filed the instant case
    asserting infringement of the ’950 patent. Claims 9 and
    11, both of which depend from claim 8, are the only claims
    at issue:
    8. A drug formulation in the form of an uncoated
    tablet which disintegrates rapidly in the mouth
    and releases the drug in the mouth without swal-
    lowing the tablet comprising vardenafil hydro-
    chloride trihydrate, and at least two sugar
    alcohols.
    9. The drug formulation according to claim 8,
    wherein said sugar alcohols are a mixture of sor-
    bitol and mannitol.
    11. The drug formulation of claim 8, wherein at
    least one sugar alcohol is sorbitol.
    The parties agree that claim 8’s requirement that the
    formulation “releases the drug in the mouth” means it is
    an immediate-release formulation.
    The district court held a six-day bench trial to consid-
    er the validity of the ’950 patent. Watson argued the
    claimed formulation of vardenafil would have been obvi-
    ous to a person of ordinary skill in the art based on multi-
    ple exemplary references showing a motivation to:
    4                    BAYER PHARMA AG   v. WATSON LABS., INC.
    (1) create an ODT formulation of vardenafil 2; (2) select
    mannitol and sorbitol as sugar alcohols3; and (3) make the
    2   The prior art relied on by Watson at trial and dis-
    cussed herein are, for the vardenafil ODT limitation:
    (1) Chang et al., “Fast Dissolving Tablets,” Pharmaceuti-
    cal Technology, Vol. 24 No. 6 (“Chang”); (2) U.S. Patent
    Application Pub. No. 2002/0091129 (“Boolell”); (3) U.S.
    Patent No. 6,683,080 (“Fryburg”); (4) “Pfizer/Scherer deal
    on fast-acting Viagra,” SCRIP World Pharmaceutical
    News, No. 2332/22 (May 6th/8th 1998) (“SCRIP”);
    (5) Habib et al., “Fast Dissolving Drug Delivery Systems,”
    17 Critical Reviews in Therapeutic Drug Carrier Systems
    61 (2000) (“Habib”); (6) Ghosh et al., “Intraoral Delivery
    Systems: An Overview, Current Status, and Future
    Trends” in Drug Deliver to the Oral Cavity: Molecules to
    Market (Ghosh et al., eds., 2005) (“Ghosh”); (7) U.S.
    Patent Application Pub. No. 2002/0002172 (“Bell-Huff”);
    (8) European Patent Application Pub. No. EP1120120
    (“Furitsu”); and (9) PCT Application Pub. No. WO
    02/05820 (“Chen”).
    3   The prior art relied on by Watson at trial and dis-
    cussed herein are, for the sorbitol and mannitol limita-
    tion: (1) Fu et al., “Orally Fast Disintegrating Tablets:
    Developments, Technologies, Taste-Masking and Clinical
    Studies,” 21 Critical Reviews in Therapeutic Drug Carrier
    Systems 443 (2004) (“Fu”); (2) Bauer et al., “Particle
    design by surface modifications: spray-dying and co-
    granulation of mannitol/sorbitol mixtures,” 11 S.T.P.
    Pharma Sciences 203 (2001) (“Bauer”); (3) Joshi et al,
    “Added Functionality Excipients: An Answer to Challeng-
    ing Formulations,” Pharmaceutical Technology, June
    2004 (“Joshi”); (4) U.S. Patent No. 6,544,552 (“Sparks”);
    (5) U.S. Patent Application Pub. No. 2003/0119642
    (“Norman”); (6) SPI Pharma, “Quick-Dissolving Tablets
    Made Easy with Pharmaburst™,” Special Delivery
    (Spring 2002) (“Pharmaburst”); (7) Ghosh.
    BAYER PHARMA AG   v. WATSON LABS., INC.                      5
    ODT formulation immediate-release. The district court
    rejected each of Watson’s arguments. It found a person of
    ordinary skill in the art would not have been motivated to
    create an ODT formulation of vardenafil and would not
    have used mannitol and sorbitol as excipients. It found
    the prior art taught away from formulating vardenafil
    ODT as immediate-release. The district court also ad-
    dressed Bayer’s objective evidence of nonobviousness and
    found it supported its conclusion that Watson failed to
    prove by clear and convincing evidence that claims 9 and
    11 would have been obvious. Watson appeals. We have
    jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
    DISCUSSION
    A patent may not issue “if the differences between the
    subject matter sought to be patented and the prior art are
    such that the subject matter as a whole would have been
    obvious at the time the invention was made to a person
    having ordinary skill in the art to which said subject
    matter pertains.” 35 U.S.C. § 103. Obviousness depends
    on the following factual determinations: “(1) the scope and
    content of the prior art; (2) the differences between the
    prior art and the claims at issue; (3) the level of ordinary
    skill in the art at the time the invention was made; and
    (4) objective evidence of nonobviousness, if any.” In re
    Kubin, 
    561 F.3d 1351
    , 1356 (Fed. Cir. 2009) (citing Gra-
    ham v. John Deere Co., 
    383 U.S. 1
    , 17–18 (1966)). On
    appeal from a bench trial, we review the district court’s
    findings of fact for clear error. Pfizer, Inc. v. Apotex, Inc.,
    
    480 F.3d 1348
    , 1359 (Fed. Cir. 2007). “A finding is ‘clearly
    erroneous’ when[,] although there is evidence to support
    it, the reviewing court on the entire evidence is left with
    the definite and firm conviction that a mistake has been
    committed.” United States v. U.S. Gypsum Co., 
    333 U.S. 364
    , 395 (1948). Based on the underlying factual find-
    ings, whether a claimed invention would have been obvi-
    ous is a question of law reviewed de novo. 
    Pfizer, 480 F.3d at 1359
    .
    6                     BAYER PHARMA AG   v. WATSON LABS., INC.
    A. Vardenafil ODT Limitation
    The district court determined that Watson failed to
    meet its burden of proving by clear and convincing evi-
    dence that there would have been a motivation to formu-
    late vardenafil as an ODT formulation.                 This
    determination rested largely on the court’s finding the
    testimony of Bayer’s expert, Dr. Wicks, more persuasive
    than the testimony of Watson’s expert, Dr. Jacobs. The
    district court found it important that, according to Dr.
    Wicks, no ED ODT drug was on the market as of the
    ’950 patent’s priority date. J.A. 9–10 (citing J.A. 676
    at 855:15–19). It credited Dr. Wicks’ testimony that a
    person of ordinary skill in the art would not have focused
    on an ODT formulation of vardenafil “because of the
    rarity of ODT formulations.”        J.A. 9 (citing J.A. 671
    at 833:21–834:2). It cited Dr. Wicks’ testimony in finding
    that a person of ordinary skill in the art “would not have
    considered vardenafil to be a good candidate for formula-
    tion as an ODT because vardenafil was known as an [ED]
    medication and ODTs were not considered particularly
    applicable to this area.”       J.A. 9 (citing J.A. 675–76
    at 852:13–853:4, 853:25–854:4).
    The district court cited the absence of any other ODT
    formulations of ED drugs on the market as of the
    ’950 patent’s priority date. It cited the Fu reference,
    which, like the SCRIP reference, showed Pfizer an-
    nounced plans to launch an ODT version of Viagra
    (sildenafil) in May 1998, but noted Pfizer still had not
    brought the product to market by March 2005. J.A. 9
    (citing J.A. 19103–04). Despite the fact that the 2005
    Ghosh reference stated that Pfizer was continuing to
    develop an ODT formulation of sildenafil, the court found
    this not persuasive because it concluded that the refer-
    ence’s claim was based on a publication from 1998. J.A. 9
    (citing J.A. 19196–97, 19210). It cited the Habib refer-
    ence, which did not list ED drugs in its table titled “Vari-
    ous Therapeutic Areas in Which the Fast-Dissolve Dosage
    BAYER PHARMA AG   v. WATSON LABS., INC.                  7
    Forms are Most Applicable,” to support finding that ODTs
    were not particularly applicable to ED drugs. J.A. 9
    (citing J.A. 19265).
    The clear error in the district court fact finding that
    there was no motivation to formulate ED drugs in ODTs,
    is that it concluded that the record did not contain an
    indication that ED drugs would be good candidates for
    ODT formulations. See, e.g., J.A. 9 (finding “vardenafil
    was known as an [ED] medication and ODTs were not
    considered particularly applicable to this area”). This is
    simply not accurate. Watson relied on nine prior art
    references to support its assertion that there would have
    been a motivation to create an ODT formulation of var-
    denafil. Dr. Jacobs testified that the Chang reference
    states “drugs for [ED] would be good candidates for ODT
    formulation.” J.A. 448 at 310:20–311:11. He testified the
    Boolell and Fryburg references each disclose formulating
    vardenafil as an ODT. J.A. 448–49 at 3:11:17–312:6. He
    testified that numerous companies had already begun
    formulating ODT versions of ED drugs: Pfizer filed the
    Bell-Huff patent application directed to sildenafil ODT;
    Eisai filed the Furitsu patent application claiming an
    ODT formulation of phosphodiesterase inhibitors; and
    Lavipharm filed the Chen international patent applica-
    tion, identifying ODT versions of sildenafil. J.A. 449–50
    at 314:3–319:1. Watson’s post-trial briefing identifies the
    same set of references, all of which were produced as trial
    exhibits and filed with the court.
    These six references—Chang, Boolell, Fryburg, Bell-
    Huff, Furitsu, and Chen—are absent from the district
    court’s decision. While it is certainly not necessary for a
    district court to evaluate all references presented to it,
    nowhere here does it mention these key references in
    analyzing whether the prior art taught vardenafil ODT or
    whether a skilled artisan would have been motivated to
    formulate vardenafil ODT. These references are highly
    relevant to whether a person of ordinary skill in the art
    8                     BAYER PHARMA AG   v. WATSON LABS., INC.
    would have been motivated to formulate ODT vardenafil.
    And their express disclosures cause the district court fact
    finding regarding motivation to combine to be clear error.
    See 
    Pfizer, 480 F.3d at 1363
    (holding the district court
    clearly erred when it failed to consider relevant prior art).
    The district court’s finding that “the [person of ordi-
    nary skill in the art] would not have considered vardenafil
    to be a good candidate for formulation as an ODT because
    vardenafil was known as an erectile dysfunction medica-
    tion and ODTs were not considered particularly applica-
    ble to this area” is contradicted by the references cited by
    Dr. Jacobs that the court failed to consider. J.A. 9; see
    also 
    id. (“[T]here was
    no reason for the [person of ordinary
    skill in the art] to focus on an ODT vardenafil because of
    the rarity of ODT formulations.”). All six of the prior art
    references disregarded by the district court identify ED
    drugs as ODT formulations. Chang identifies ED drugs
    as one of five drug classes considered candidates for fast-
    dissolving tablets. J.A. 19024. Boolell states ED drugs
    such as sildenafil and vardenafil can be “administered
    orally, buccally or sublingually in the form of tablets” and
    “may also be administered as fast-dispersing or fast-
    dissolving dosage forms.” J.A. 19689–90 ¶¶ 49–54, 63.
    Fryburg provides the same disclosure, limited to varden-
    afil. J.A. 19677 at 6:31–39. Bell-Huff, Furitsu, and Chen
    show that between 1999 and 2001, more than one compa-
    ny sought patent protection on ODT formulations of ED
    drugs. Bell-Huff is directed to “rapidly disintegrating oral
    dosage forms which contain sildenafil.” J.A. 19683 ¶ 2.
    Furitsu is titled “Tablets Immediately Disintegrating in
    the Oral Cavity” and is directed to phosphodiesterase
    inhibitors, the class in which vardenafil, sildenafil, and
    tadalafil belong. J.A. 19077. And Chen is directed to
    sildenafil formulations, one example of which includes a
    “fast dissolving tablet.” J.A. 19797. All of these refer-
    ences indicate a person of ordinary skill in the art would
    have considered ODT formulations applicable to ED
    BAYER PHARMA AG   v. WATSON LABS., INC.                   9
    drugs. And several of these references indicate a person
    of ordinary skill in the art would have considered ODT
    formulations to be applicable to vardenafil in particular.
    Bayer argues that Watson’s arguments concerning
    many of its references, such as Chang, Boolell, and Fry-
    burg, were insignificant and the district court did not
    clearly err by failing to address them. It argues that
    while Watson asserts on appeal that the district court
    ignored its key prior art, Watson flooded the district court
    with references without adequately addressing them. We
    do not agree.
    Watson produced a significant number of references to
    support its argument that a person of ordinary skill in the
    art would have been motivated to formulate an ODT
    formulation of vardenafil. While it may at times be
    unwise for a party to rely on numerous prior art refer-
    ences when challenging a patent on obviousness grounds,
    Watson’s approach was not untenable here. Watson
    produced these nine references to support a narrow point:
    they each “disclosed formulating vardenafil and other
    approved ED drugs into ODTs.” J.A. 935. Its expert,
    Dr. Jacobs, addressed each of these nine references after
    he was asked, “were there any references that discussed
    formulating erectile dysfunction drugs in particular into
    ODTs?” J.A. 448–50 at 310:20–319:1. Chang, Boolell,
    and Fryburg were the first three references he discussed.
    J.A. 448–49 at 310:20–313:13. Watson addressed the
    same nine references in its post-trial briefing under the
    heading, “The Prior Art Suggested Formulating Varden-
    afil and Other Approved ED Drugs as ODTs.” J.A. 935.
    While Watson’s discussion of the various references was
    at times succinct, Dr. Jacobs’ testimony and Watson’s
    arguments were tailored to the simple point that ODT
    formulations of ED drugs were known. It is unnecessary,
    for example, to delve deeply into the meaning of a patent
    application directed to an “intraoral quickly disintegrat-
    ing tablet containing a phosphodiesterase inhibitor” to
    10                   BAYER PHARMA AG   v. WATSON LABS., INC.
    explain that application discloses an ODT formulation of
    an ED drug. J.A. 19077 (Furitsu); see J.A. 450 at 316:23–
    318:10 (Dr. Jacobs’ testimony); J.A. 936–37 (Watson’s
    post-trial briefing). Chang’s listing of “drugs for [ED]”
    among five types of drugs that can be considered for ODTs
    speaks for itself. J.A. 19024; see J.A. 448 at 310:24–
    311:16 (Dr. Jacobs’ testimony); J.A. 937 (Watson’s post-
    trial briefing). Watson clearly presented and preserved
    its arguments relating to the prior art for the vardenafil
    ODT limitation. In light of these references, the district
    court clearly erred in determining that one of skill would
    not have been motivated to make ODT formulations of ED
    drugs.
    Dr. Wicks’ testimony does not cast doubt on the
    weight of Watson’s evidence regarding the vardenafil
    ODT limitation. Many of the references Watson relies on
    for this limitation were unchallenged by Dr. Wicks. For
    example, Dr. Wicks did not present testimony on Chang’s
    disclosure that ED drugs can be considered candidates for
    ODTs. He did not question or critique any of the three
    patent applications directed to ODT formulations of ED
    drugs—Bell-Huff, Furitsu, and Chen. His only discussion
    of Bell-Huff concerned the immediate-release limitation,
    and he did not mention Furitsu or Chen at all. Rather,
    Dr. Wicks’ testimony that a person of ordinary skill in the
    art would not have considered ODTs applicable to ED
    drugs, on which the district court relied, was expressly
    limited to the Habib and Fu references. See J.A. 9;
    J.A. 676 at 853:25–854:4 (Q: “Okay. So in light of the
    information that we saw in Habib and Fu, if the person of
    ordinary skill were to think about alternate formulations
    of vardenafil, would they focus on ODTs?” A: “No.
    There’s no indication that they’re applicable.”). In fact,
    Dr. Wicks expressly conceded that the prior art described
    ED drugs as candidates for ODT formulations. J.A. 690
    at 911:23–912:2. This case does not present a situation in
    which the district court’s credibility determination can be
    BAYER PHARMA AG   v. WATSON LABS., INC.                     11
    understood to discount the prior art references it failed to
    address based on one expert’s characterization of the prior
    art. See, e.g., Senju Pharm. Co. v. Lupin Ltd, 
    780 F.3d 1337
    , 1351 (Fed. Cir. 2015) (deferring to district court’s
    credibility determination to credit competing testimony
    regarding the prior art’s teaching).
    It is well within the district court’s discretion to credit
    one expert’s competing testimony over another. We “must
    give due regard to the trial court’s opportunity to judge
    the witnesses’ credibility.” Fed. R. Civ. P. 52(a)(6); see
    FilmTec Corp. v. Hydranautics, 
    982 F.2d 1546
    , 1553 (Fed.
    Cir. 1992) (“We will not invade the province of the district
    court to judge matters of credibility.”). But a district
    court cannot, through a credibility determination, ignore
    the wealth of evidence, especially as in this case where
    the expert did not even address it. The district court’s
    finding that ODTs were not considered applicable to ED
    drugs is clearly erroneous in light of Watson’s evidence.
    See J.A. 9.
    The remainder of the district court’s findings underly-
    ing the motivation to formulate vardenafil ODT focused
    too heavily on the commercial availability of ODT formu-
    lations of ED drugs as of the ’950 patent’s priority date.
    See, e.g., J.A. 9 (finding “it important that prior art refer-
    ences from 2004 listing ODTs on the market and likely to
    come to market in the next few years did not list any
    drugs for the treatment of erectile dysfunction”); J.A. 10
    (“[N]o ODT of an erectile dysfunction drug was on the
    market by March 2005.”). It is unclear why the district
    court found it important that no ODT ED drug had gained
    FDA approval as of ’950 patent’s priority date. The
    motivation to combine inquiry is not limited to what
    products are forthcoming or currently available on the
    market. Particularly given the lengthy FDA approval
    process, the pharmaceutical industry is no exception. Any
    motivation, “whether articulated in the references them-
    selves or supported by evidence of the knowledge of a
    12                    BAYER PHARMA AG   v. WATSON LABS., INC.
    skilled artisan, is sufficient.” Outdry Techs. Corp. v. Geox
    S.p.A., 
    859 F.3d 1364
    , 1370–71 (Fed Cir. 2017). Here, the
    motivation to formulate an ODT version of vardenafil is
    plainly evident from the face of multiple prior art refer-
    ences disclosing ODT formulations of ED drugs. No
    further rationale for developing vardenafil ODT was
    necessary. On review of the entire record evidence before
    the district court, we are left with the definite and firm
    conviction that the district court clearly erred when it
    found there would not have been a motivation to formu-
    late vardenafil ODT.
    B. Sorbitol and Mannitol Limitation
    Claim 9 requires the vardenafil ODT formulation con-
    tain a mixture of sorbitol and mannitol, and claim 11
    more generally requires that the ODT formulation contain
    at least two sugar alcohols, one of which must be sorbitol.
    Neither party disputes that it was known—if not neces-
    sary—to include a sugar alcohol in ODT formulations.
    The parties’ dispute rests on whether a person of ordinary
    skill in the art would have been motivated to select the
    claimed combination of sugar alcohols, sorbitol and man-
    nitol.
    The district court found a person of ordinary skill in
    the art would not have been motivated to use mannitol
    and sorbitol in an ODT formulation, finding Dr. Wicks’
    testimony on this limitation more credible than
    Dr. Jacobs’. It found Dr. Jacobs’ reliance on the Bauer
    reference unpersuasive because Bauer’s disclosure that
    the combination of mannitol and sorbitol could optimize
    tableting properties was based on a 1978 article. J.A. 12
    (citing J.A. 467 at 385:19–386:12; J.A. 18593–94 (Bauer)).
    It noted Dr. Jacobs relied on the Pharmaburst reference,
    which advertised an off-the-shelf excipient containing a
    combination of mannitol and sorbitol, but found it con-
    tained no working examples or experimental data.
    J.A. 12–13 (citing J.A. 454–55 at 335:23–336:1). It found
    BAYER PHARMA AG   v. WATSON LABS., INC.                  13
    Dr. Jacobs’ testimony that a skilled artisan would have
    been motivated to use a mixture of sorbitol and mannitol
    to avoid the need for specialized packaging unpersuasive
    in light of his contrary testimony that “there is no need
    for specialized packaging” when a particular manufactur-
    ing process is employed. J.A. 13 (citing J.A. 453 at 328:3–
    15 (discussing the Joshi reference); J.A. 446 at 301:16–
    302:1). It found persuasive Dr. Wicks’ testimony that
    “every ODT on the market in the relevant prior art time
    frame contained only a single sugar alcohol: mannitol,”
    and that “there were no known problems with the use of
    mannitol in the existing ODTs.” J.A. 12 (citing J.A. 683
    at 884:1–19; J.A. 685 at 891:11–17). It found “there was
    nothing in the prior art that would have given the [person
    of ordinary skill in the art] a reason to use sorbitol in
    addition to mannitol in an ODT.” J.A. 12 (citing J.A. 686
    at 894:12–15).
    We do not question the district court’s credibility de-
    terminations. However, the district court’s analysis for
    the sorbitol and mannitol limitation again focused on the
    commercial availability of products while failing to ad-
    dress relevant prior art. Upon consideration of the entire
    record and under a proper analysis, we conclude that the
    district court clearly erred in finding a person of ordinary
    skill in the art would not have been motivated to formu-
    late an ODT with sorbitol and mannitol.
    The parties do not dispute that as of the ’950 patent’s
    priority date, a company named SPI Pharma marketed an
    off-the-shelf ODT excipient product called Pharmaburst.
    The parties agree Pharmaburst existed in three different
    forms: two using only mannitol and a third, Pharmaburst
    B2, containing mannitol and sorbitol. The ’950 patent
    specification uses Pharmaburst B2 in an example. See
    ’950 patent at 6:31–34. Thus there can be no question
    that it was known as of the ’950 patent’s priority date to
    use sorbitol and mannitol in ODT formulations.
    14                     BAYER PHARMA AG    v. WATSON LABS., INC.
    Dr. Jacobs testified that the Norman reference, not
    addressed by the district court, discloses examples of ODT
    formulations using sorbitol and mannitol created by SPI
    Pharma. See J.A. 19727–28 at Exs. 1, 3, and 4; J.A. 453–
    54 at 331:21–332:23 (Dr. Jacobs’ testimony). The district
    court mentioned Dr. Jacobs relied on the Sparks refer-
    ence, J.A. 12, but did not explain why Sparks’ examples
    using sorbitol and mannitol in ODT formulations were not
    relevant to whether a skilled artisan would have used
    sorbitol and mannitol in vardenafil ODT, or give any
    reason why that reference would not inform the obvious-
    ness analysis. See J.A. 19671 at Exs. 1, 2 (explaining
    tablet disintegration times of 3 and 7 seconds); J.A. 453
    at 330:18–331:23 (Dr. Jacobs’ testimony).            Dr. Wicks
    likewise provided no rebuttal testimony regarding these
    references. Other than critiquing its lack of examples or
    experimental data, J.A. 12–13, the district court’s decision
    does not otherwise mention the Pharmaburst advertise-
    ment, or its disclosure that it is “an ‘off the shelf’ excipient
    which allows you to develop your own quick dissolve
    formulations in-house quickly and much more cost effec-
    tively.” J.A. 18554; see also J.A. 454–55 at 335:18–337:9
    (Dr. Jacobs’ testimony). Its decision does not mention
    Ghosh’s similar disclosure that Pharmaburst “is a highly
    flexible, rapidly disintegrating excipient that imparts a
    smooth creamy mouth feel, and is manufactured under
    cGMPs.” J.A. 19173; J.A. 455 at 337:13–23 (Dr. Jacobs’
    testimony).
    The district court clearly erred when it found “there
    was nothing in the prior art that would have given the
    [person of ordinary skill in the art] a reason to use sorbi-
    tol in addition to mannitol in an ODT.” J.A. 12. The
    Joshi reference states using sorbitol with mannitol in
    ODTs is advantageous because it “enable[s] strong bind-
    ing and result[s] in a more robust tablet at low compres-
    sion forces.” J.A. 19820–21; J.A. 938 (Watson’s post-trial
    briefing). It explains that, “[i]n addition to contributing to
    BAYER PHARMA AG   v. WATSON LABS., INC.                   15
    the robustness of tablets, the sorbitol also imparts a sweet
    taste and a unique texture to the mannitol, thereby
    improving the ODT formulation’s mouthfeel” without
    affecting    pharmacopeial        conformity     standards. 4
    J.A. 19821. Particularly in light of the district court’s
    finding that a person of ordinary skill in the art “would
    have expected a vardenafil ODT to have a bitter taste,”
    J.A. 10, these disclosures are relevant to whether a skilled
    artisan would have been motivated to use sorbitol and
    mannitol in vardenafil ODT. The district court’s finding
    that nothing in the prior art provided a reason to use
    sorbitol in addition to mannitol in an ODT is clearly
    erroneous in light of Watson’s evidence. See J.A. 12.
    The district court’s remaining findings on the motiva-
    tion to use sorbitol and mannitol in an ODT formulation 5
    focused solely on the ODT market as of the ’950 patent’s
    priority date. See J.A. 12 (“[E]very ODT on the market in
    the relevant prior art time framed contained only a single
    sugar alcohol: mannitol.”); 
    id. (“[T]here were
    no known
    problems with the use of mannitol in the existing ODTs.”).
    Dr. Wicks likewise critiqued Pharmaburst because it was
    not “in any approved product in the United States as of
    March 2005.” J.A. 683 at 884:20–23; see also J.A. 684
    at 885:2–15 (testifying that a person of ordinary skill in
    4    While the district court found part of Dr. Jacobs’
    testimony regarding Joshi—that it would have been
    desirable to add sorbitol to mannitol to avoid the need for
    specialized packaging—unpersuasive, it never addressed
    Joshi’s express disclosures regarding the benefits of using
    sorbitol with mannitol.       See J.A. 13 (citing J.A. 453
    at 328:3–15).
    5    Because it is not necessary to our analysis, we do
    not address the district court’s finding that the Bauer
    reference was not relevant because it was based on a 1978
    article. See J.A. 12.
    16                    BAYER PHARMA AG   v. WATSON LABS., INC.
    the art would look to currently-available ODT products to
    know whether the FDA considered the excipients safe and
    effective). Accepting fully Dr. Wicks’ testimony on this
    point, the motivation to combine inquiry for drug formula-
    tions is not limited to what already has or could gain FDA
    approval. We have previously explained:
    There is no requirement in patent law that the
    person of ordinary skill be motivated to develop
    the claimed invention based on a rationale that
    forms the basis for FDA approval. Motivation to
    combine may be found in many different places
    and forms; it cannot be limited to those reasons
    the FDA sees fit to consider in approving drug ap-
    plications.
    Allergan, Inc. v. Sandoz Inc., 
    726 F.3d 1286
    , 1292 (Fed.
    Cir. 2013). While FDA approval may be relevant to the
    obviousness inquiry, see 
    id. at 1291–92,
    a lack of FDA
    approval cannot negate an otherwise apparent motivation
    to formulate a product. The district court clearly erred in
    finding no motivation to use sorbitol and mannitol in
    ODTs; Watson’s evidence expressly demonstrated that
    sorbitol and mannitol in ODTs was known in the art and
    that there were advantageous reasons to use them.
    C. Immediate-Release Limitation
    The district court found that even if a skilled artisan
    would have been motivated to make an ODT formulation
    of vardenafil, the prior art taught away from formulating
    vardenafil ODT as immediate release. J.A. 10–11. The
    parties agree that only two types of ODT formulations
    were known in the art: immediate-release ODTs, which
    are released in the mouth, and delayed-release ODTs,
    which are released in the stomach. The district court
    found, based again on expert testimony, that a person of
    ordinary skill in the art would have expected vardenafil
    ODT to have a bitter taste, which would have discouraged
    him from creating a formulation that releases vardenafil
    BAYER PHARMA AG   v. WATSON LABS., INC.                  17
    in the mouth. J.A. 10. It also found a person of ordinary
    skill in the art would have been concerned with using an
    immediate-release formulation because it would be ex-
    pected to increase bioavailability, and Levitra’s label
    suggested an increase in vardenafil blood levels would be
    a problem for older men. J.A. 11. The district court found
    these two concerns would have taught away from an
    immediate-release formulation. 
    Id. We do
    not disturb the district court’s findings relating
    to vardenafil’s expected bitter taste and increased bioa-
    vailability, but the district court erred when it elevated
    those findings to teaching away. “A reference teaches
    away when it suggests that the line of development
    flowing from the reference’s disclosure is unlikely to be
    productive of the result sought by the applicant.” Santa-
    rus, Inc. v. Par Pharm., Inc., 
    694 F.3d 1344
    , 1354 (Fed.
    Cir. 2012) (quoting Medichem, S.A. v. Rolabo, S.L., 
    437 F.3d 1157
    , 1165 (Fed. Cir. 2006) (alterations omitted)).
    The district court did not find that a person of ordinary
    skill in the art would have believed vardenafil’s expected
    bitter taste and increased bioavailability would have
    likely rendered an immediate-release formulation unpro-
    ductive. Instead, the district court’s analysis focused on
    whether a person of ordinary skill in the art would “nec-
    essarily have made an immediate-release ODT rather
    than a delayed-release ODT.” J.A. 10; see J.A. 11 (finding
    teaching away based on these “two fundamental concerns
    when considering an immediate-release formulation over
    a delayed release ODT formulation”). But the teaching
    away inquiry does not focus on whether a person of ordi-
    nary skill in the art would have merely favored one dis-
    closed option over another disclosed option. In assessing
    whether prior art teaches away, that “better alternatives
    exist in the prior art does not mean that an inferior
    combination is inapt for obviousness purposes.” In re
    Mouttet, 
    686 F.3d 1322
    , 1334 (Fed. Cir. 2012). When
    there are only two possible formulations and both are
    18                    BAYER PHARMA AG   v. WATSON LABS., INC.
    known in the art at the time, the fact that there may be
    reasons a skilled artisan would prefer one over the other
    does not amount to a teaching away from the lesser
    preferred but still workable option. The district court’s
    finding that a person of ordinary skill in the art would
    have first pursued a delayed-release formulation over an
    immediate-release formulation is insufficient to support a
    finding of teaching away.
    The evidence before the district court supports its
    finding that a person of ordinary skill in the art may have
    preferred a delayed-release formulation over immediate
    release—not that an immediate-release formulation was
    unlikely to be productive in vardenafil ODT. Rather than
    testify that a skilled artisan would have believed the taste
    of vardenafil is too bitter to formulate as an immediate-
    release ODT, Dr. Wicks merely testified that “the consid-
    eration would lead them to a delayed-release ODT.”
    J.A. 678 at 863:22–864:7 (answering “would the person of
    ordinary skill have a reason to make a formulation of
    vardenafil, an ODT formulation, that releases the drug in
    the mouth, the immediate-release type?”).           Nor did
    Dr. Wicks point to prior art suggesting vardenafil would
    have tasted too bitter. Dr. Wicks conceded “[t]he taste of
    vardenafil was not reported in the literature” and dis-
    claimed that a person of ordinary skill in the art “would
    have assumed that vardenafil was as bitter as sildenafil.”
    J.A. 694 at 925:16–926:4. When asked about bioavailabil-
    ity concerns due to Levitra’s label, Dr. Wicks again fo-
    cused on why those concerns would have caused a skilled
    artisan to prefer a delayed-release formulation. See
    J.A. 681 at 874:17–23 (testifying “the making of a de-
    layed-release ODT would be far simpler”). Dr. Wicks
    opined that the bioavailability concerns “would clearly
    teach away from making an immediate-release formula-
    tion,” but when asked why, he answered “[b]ecause you
    would get much greater control with a delayed-release
    formulation.”     J.A. 681 at 873:8–25.     This testimony
    BAYER PHARMA AG   v. WATSON LABS., INC.                  19
    supports the district court’s finding that the taste and
    bioavailability of vardenafil raised concerns, and that a
    skilled artisan may have preferred a delayed-release
    formulation, but it does not support a finding of teaching
    away. See KSR Int’l Co. v. Teleflex Inc., 
    550 U.S. 398
    , 425–26 (2007) (holding expert’s declaration did not
    support finding teaching away because it did not indicate
    the prior art system “was somehow so flawed that there
    was no reason to upgrade it”).
    While the district court did not clearly err in its fact
    finding that a skilled artisan would have had concerns
    over an immediate-release formulation due to vardenafil’s
    expected bitter taste and bioavailability, obviousness
    “does not require that the motivation be the best option,
    only that it be a suitable option from which the prior art
    did not teach away.” 6 Par Pharm., Inc. v. TWI Pharm.,
    Inc., 
    773 F.3d 1186
    , 1197–98 (Fed. Cir. 2014). We deter-
    mine whether a skilled artisan would have found the
    claimed combination obvious weighing the four Graham
    factors, which includes the district court’s fact findings
    regarding the bitter taste and bioavailability of immediate
    release formulations. See Apple Inc. v. Samsung Elecs.
    Co., 
    839 F.3d 1034
    , 1048 (Fed. Cir. 2016) (en banc).
    6    We also note the district court did not address
    record evidence that may have alleviated concerns with
    an immediate-release formulation, including that
    Pharmaburst “is a highly flexible, rapidly disintegrating
    excipient that imparts a smooth creamy mouth feel, and is
    manufactured under cGMPs.” J.A. 19173. It did not
    address evidence that using sorbitol with mannitol in
    ODTs benefited tableting properties, taste, and mouth-
    feel. J.A. 19820–21 (adding sorbitol to ODTs “imparts a
    sweet taste and a unique texture to the mannitol, thereby
    improving the ODT formulation’s mouthfeel”).
    20                   BAYER PHARMA AG   v. WATSON LABS., INC.
    D. Objective Evidence
    The district court found Watson’s copying of the
    claimed invention and Staxyn’s unexpected increased
    duration of action compared to Levitra supported its
    conclusion of nonobviousness. J.A. 16–19. We do not
    disturb these findings. Copying is one of the objective
    indicia we have held is probative of nonobviousness.
    
    Apple, 839 F.3d at 1052
    . Both Bayer’s evidence of copying
    and unexpected results weigh in favor of the nonobvious-
    ness of the claimed combination.
    E. Legal Conclusion of Obviousness
    We consider whether the claimed invention would
    have been obvious de novo based on underlying findings of
    fact. 
    Pfizer, 480 F.3d at 1359
    . Watson demonstrated by
    clear and convincing evidence that there would have been
    a motivation to formulate an ODT version of vardenafil.
    In fact, the prior art was explicit in the suggestion to
    make such a combination and the district court clearly
    erred in its fact finding to the contrary. The prior art of
    record expresses a clear motivation to formulate ODT
    versions of ED drugs and that multiple companies were
    formulating ODT versions of ED drugs. See J.A. 19024,
    19077, 19683 ¶ 2, 19797. Watson also demonstrated by
    clear and convincing evidence that there was an express
    motivation in the prior art to use sorbitol and mannitol as
    the excipients in the ODT formulation of the ED drug and
    the district court clearly erred in its fact finding to the
    contrary. Pharmaburst B2 was a known, off-the-shelf
    ODT excipient product that permitted formulation of ODT
    products “in-house quickly and much more cost effective-
    ly.” J.A. 18554. The district court did not clearly err in
    its fact finding that a person of ordinary skill in the art
    would have had concerns using an immediate-release
    formulation due to vardenafil’s expected bitter taste and
    bioavailability; however, it clearly erred when it conclud-
    ed that those findings taught away from the immediate
    BAYER PHARMA AG   v. WATSON LABS., INC.                  21
    release. Bayer presented evidence of copying and unex-
    pected results that weigh in favor of a conclusion of non-
    obviousness.
    Weighing all four Graham factors, we conclude
    claims 9 and 11 of the ’950 patent would have been obvi-
    ous. The repeated suggestion in the prior art to make an
    ODT formulation of an ED drug and the suggestion to use
    the combination of sorbitol and mannitol as excipients are
    strong evidence of a motivation to make the claimed
    combination. The parties agree that ODTs were known to
    exist as either immediate-release or delayed-release
    formulations. A skilled artisan motivated to formulate
    vardenafil ODT would have been faced with a design need
    for its release profile, and an immediate-release formula-
    tion would have been one of two options. See 
    KSR, 550 U.S. at 402
    (“When there is a design need or market
    pressure to solve a problem and there are a finite number
    of identified, predictable solutions, a person of ordinary
    skill in the art has good reason to pursue the known
    options within his or her technical grasp.”). While a
    skilled artisan may have preferred a delayed-release
    formulation over the claimed immediate-release formula-
    tion, “that the prior art as a whole suggests the desirabil-
    ity of a particular combination need not be supported by a
    finding that the prior art suggests that the combination
    claimed . . . is the preferred, or most desirable, combina-
    tion.” In re Fulton, 
    391 F.3d 1195
    , 1200 (Fed. Cir. 2004).
    Weighing this evidence together with the objective evi-
    dence of unexpected results and copying, we conclude that
    a skilled artisan would have found the claimed combina-
    tion obvious. The district court’s final judgment is re-
    versed.
    CONCLUSION
    For the reasons discussed above, we reverse the dis-
    trict court’s holding that Watson failed to prove by clear
    and convincing evidence that claims 9 and 11 of the
    22                      BAYER PHARMA AG   v. WATSON LABS., INC.
    ’950 patent would have been obvious.
    REVERSED
    COSTS
    Costs to Watson.