Opinion · Court of Appeals for the Federal Circuit

Novartis Pharmaceuticals Corporation v. Torrent Pharma Inc.

Novartis Pharms. Corp. v. Torrent Pharma Inc., No. 23-2218, UP10778358 (Fed. Cir. Jan. 10, 2025)

Type
Opinion
Court
Court of Appeals for the Federal Circuit
Jurisdiction
Federal
Date
2025-01-10
Topic
bankruptcy

Case: 23-2218 Document: 106 Page: 1 Filed: 01/10/2025 United States Court of Appeals for the Federal Circuit ______________________ IN RE: ENTRESTO (SACUBITRIL/VALSARTAN) -------------------------------------------------- NOVARTIS PHARMACEUTICALS CORPORATION, Plaintiff-Appellant v. TORRENT PHARMA INC., TORRENT PHARMACEUTICALS LTD. Defendants -------------------------------------------------- NOVARTIS PHARMACEUTICALS CORPORATION, Plaintiff-Appellant v. ALEMBIC PHARMACEUTICALS LIMITED, ALEMBIC PHARMACEUTICALS INC., Defendants -------------------------------------------------- NOVARTIS PHARMACEUTICALS CORPORATION, Plaintiff-Appellant v. MSN PHARMACEUTICALS, INC., MSN Case: 23-2218 Document: 106 Page: 2 Filed: 01/10/2025 2 NOVARTIS PHARMACEUTICALS CORPORATION v.

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Case: 23-2218     Document: 106           Page: 1        Filed: 01/10/2025




    United States Court of Appeals
        for the Federal Circuit
                    ______________________

    IN RE: ENTRESTO (SACUBITRIL/VALSARTAN)

            --------------------------------------------------

  NOVARTIS PHARMACEUTICALS CORPORATION,
               Plaintiff-Appellant

                                   v.

         TORRENT PHARMA INC., TORRENT
            PHARMACEUTICALS LTD.
                   Defendants

            --------------------------------------------------

  NOVARTIS PHARMACEUTICALS CORPORATION,
               Plaintiff-Appellant

                                   v.

      ALEMBIC PHARMACEUTICALS LIMITED,
        ALEMBIC PHARMACEUTICALS INC.,
                  Defendants

            --------------------------------------------------

  NOVARTIS PHARMACEUTICALS CORPORATION,
               Plaintiff-Appellant

                                   v.

        MSN PHARMACEUTICALS, INC., MSN
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 2                 NOVARTIS PHARMACEUTICALS CORPORATION v.
                                      TORRENT PHARMA INC.


     LABORATORIES PRIVATE LTD., MSN LIFE
           SCIENCES PRIVATE LTD.,
              Defendants-Appellees

     HETERO USA, INC., HETERO LABS LIMITED,
         HETERO LABS LIMITED UNIT-III,
                    Defendants
              ______________________

                2023-2218, 2023-2220, 2023-2221
                    ______________________

     Appeals from the United States District Court for the
 District of Delaware in Nos. 1:19-cv-01979-RGA, 1:19-cv-
 02021-RGA, 1:19-cv-02053-RGA, 1:19-cv-02053-RGA, 1:20-
 md-02930-RGA, Judge Richard G. Andrews.
                  ______________________

                  Decided: January 10, 2025
                   ______________________

     DEANNE MAYNARD, Morrison & Foerster LLP,
 Washington, DC, argued for plaintiff-appellant. Also
 represented by SETH W. LLOYD; NICHOLAS NICK KALLAS,
 CHRISTINA A. L. SCHWARZ, Venable LLP, New York, NY.

     WILLIAM A. RAKOCZY, Rakoczy Molino Mazzochi Siwik
 LLP, Chicago, IL, argued for defendants-appellees. Also
 represented by KEVIN E. WARNER; RONALD M. DAIGNAULT,
 RICHARD JUANG, Daignault Iyer LLP, Vienna, VA.

                    ______________________

     Before LOURIE, PROST, and REYNA, Circuit Judges.
 LOURIE, Circuit Judge.
     Following a three-day bench trial, the United States
 District Court for the District of Delaware determined that
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 NOVARTIS PHARMACEUTICALS CORPORATION v.                   3
 TORRENT PHARMA INC.


 claims 1–4 of U.S. Patent 8,101,659 (“the ’659 patent”) were
 not shown to be invalid for obviousness, lack of
 enablement, or indefiniteness, but were shown to be
 invalid for lack of written description. In re Entresto
 (Sacubitril/Valsartan) Pat. Litig., No. 20-md-2930,
 
2023 WL 4405464
, at *13, *21, *22 (D. Del. July 7, 2023)
 (“Decision”). Judgment was entered on those grounds.
 Appellant     Novartis     Pharmaceuticals      Corporation
 (“Novartis”) challenges the district court’s written
 description     determination.           Appellees     MSN
 Pharmaceuticals, Inc., MSN Laboratories Private Ltd., and
 MSN Life Sciences Private Ltd. (collectively, “MSN”)1
 argue that the judgment of invalidity should be affirmed,
 either by affirming the district court’s written description
 determination or, alternatively, by reversing the district
 court’s obviousness or enablement determinations.
     For the following reasons, we reverse the district
 court’s determination that the claims lack an adequate
 written description, and we affirm its determinations that
 the claims were not shown to be invalid as either non-
 enabled or obvious.




     1    Of the presently named defendants, only MSN
 participates in this appeal. Each of Hetero USA Inc.,
 Hetero Labs Limited, Hetero Labs Limited Unit-III
 (collectively, “Hetero”), Torrent Pharma Inc., Torrent
 Pharmaceuticals Ltd. (collectively, “Torrent”) have since
 settled their disputes with Novartis. See ECF Nos. 57, 58,
 61, 78. Moreover, Novartis indicated that it noted an
 appeal in its case against Alembic Pharmaceuticals, Ltd.
 and Alembic Pharmaceuticals, Inc. (collectively, “Alembic”)
 only “[o]ut of an abundance of caution.” ECF No. 15 at 2
 n.1. But because the case against Alembic is stayed and
 because Alembic did not participate in the trial on the
 merits, “Alembic is not an appellee here.” 
Id.
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 4                NOVARTIS PHARMACEUTICALS CORPORATION v.
                                     TORRENT PHARMA INC.


                        BACKGROUND
                               I
     In 2015, the U.S. Food and Drug Administration
 (“FDA”) approved the New Drug Application (“NDA”) for a
 combination therapy of valsartan and sacubitril, which
 Novartis markets and sells under the brand name
 Entresto®. Entresto includes valsartan and sacubitril in a
 specific form known as a “complex,” which combines the
 two drugs into a single unit-dose-form through weak, non-
 covalent bonds. Valsartan is an angiotensin receptor
 blocker (“ARB”) that prevents angiotensin II from binding
 to its receptor, thereby reducing the blood-vessel-
 constricting effects of angiotensin II, a naturally occurring
 hormone. Sacubitril is a neutral endopeptidase (“NEP”)
 inhibitor that, like valsartan, reduces blood vessel
 constriction, but does so through a mechanism-of-action
 not involving angiotensin. At the time of its initial
 approval, Entresto was indicated to treat heart failure with
 reduced ejection fraction.        In 2019, Entresto was
 additionally approved for the treatment of heart failure in
 children, and, in 2021, it was approved for the treatment of
 heart failure with a preserved ejection fraction. In 2023
 alone, sales of Entresto in the United States totaled more
 than $3 billion.
     Entresto is protected by a number of patents, including
 the ’659 patent, which was timely listed in the Orange
 Book. The ’659 patent has a priority date of January 17,
 2002, and will expire on January 15, 2025, due to the grant
 of Patent Term Extension (“PTE”). The ’659 patent
 explains that, at the time of the invention, “the most widely
 studied” drugs to treat hypertension and heart failure were
 a class of drugs called angiotensin converting enzyme
 (“ACE”) inhibitors. ’659 patent, col. 1 ll. 55–61. Like
 valsartan and other ARBs, ACE inhibitors’ function
 involves angiotensin.         But instead of preventing
 angiotensin II from binding to its receptor, ACE inhibitors
 reduce vasoconstriction by blocking the initial formation of
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 NOVARTIS PHARMACEUTICALS CORPORATION v.                    5
 TORRENT PHARMA INC.


 angiotensin II. See Decision, at *4. The ’659 patent
 explains that, although ACE inhibitors prevent the
 formation of vasoconstrictive angiotensin II, research
 showed that the effects of those drugs may be attributed to
 other pathways. ’659 patent, col. 2 ll. 6–9. The patent also
 sets forth that, at the time of the invention, research
 showed that NEPs, like sacubitril, can lower blood pressure
 and exert effects such as diuresis. 
Id.
 col. 2 ll. 39–41.
 Sacubitril had been discovered and patented by a
 predecessor to Novartis in 1992, but as of the time of the
 invention, it “had never been administered to humans or
 tested in an animal model of hypertension and heart
 failure.” Decision, at *7.
      The patent explains that, because “the nature of
 hypertensive              vascular        diseases         is
 multifactorial[,] . . . drugs with different mechanisms of
 action have been combined.” ’659 patent, col. 2 ll. 65–67.
 But “just considering any combination of drugs having
 different modes of action does not necessarily lead to
 combinations with advantageous effects.” 
Id.
 col. 2 l. 67–
 col. 3 l. 3. Accordingly, the inventors of the ’659 patent
 sought to discover a “more efficacious combination therapy
 which has less deleterious side effects.” 
Id.
 col. 3 ll. 3–5.
 And as the specification explains, it was “surprisingly []
 found that[] a combination of valsartan and a NEP
 inhibitor achieves greater therapeutic effect than the
 administration of valsartan, ACE inhibitors or NEP
 inhibitors alone.” 
Id.
 col. 6 ll. 41–44.
     The ’659 patent has four claims, all of which are
 asserted here. Claim 1, the sole independent claim, recites:
     1. A pharmaceutical composition comprising:
        (i) the AT 1-antagonist valsartan or            a
        pharmaceutically acceptable salt thereof;
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 6                NOVARTIS PHARMACEUTICALS CORPORATION v.
                                     TORRENT PHARMA INC.


         (ii) the NEP inhibitor [sacubitril] or
         [sacubitrilat]2 or a pharmaceutically acceptable
         salt thereof; and
         (iii) a pharmaceutically acceptable carrier;
     wherein said (i) AT 1-antagonist valsartan or
     pharmaceutically acceptable salt thereof and said
     (ii) NEP inhibitor [sacubitril] or [sacubitrilat] or a
     pharmaceutically acceptable salt thereof, are
     administered in combination in about a 1:1 ratio.
 ’659 patent, col. 16 ll. 17–33. Claim 2 recites that the
 valsartan and the NEP inhibitor “are administered in
 amounts effective to treat hypertension or heart failure,”
 
id.
 col. 16 ll. 34–41; claim 3 recites that the NEP inhibitor
 is sacubitril, 
id.
 col. 16 ll. 42–45; and claim 4, which
 depends from claim 3, recites that the composition is in the
 form of a capsule or tablet, 
id.
 col. 16 ll. 46–47. On appeal,
 the validity of all of the claims rests on the same bases, so
 we will not treat them separately.
                               II
     In 2019, MSN, among other generic manufacturers,
 submitted an Abbreviated New Drug Application
 (“ANDA”) seeking FDA approval to market and sell a
 generic version of Entresto. Novartis sued MSN and the
 other generic manufacturers, alleging that the filing of the
 ANDA directly infringed claims 1–4 of the ’659 patent.



     2   Sacubitrilat is the active metabolite of the prodrug
 sacubitril, which means that, when sacubitril is ingested
 into the body, it is metabolized to sacubitrilat. Decision,
 at *1 n.3. The parties and district court used the term
 “sacubitril” to refer collectively to sacubitril, sacubitrilat,
 and their pharmaceutically acceptable salts. 
Id.
 Unless it
 is otherwise clear from context, we follow that convention
 here.
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 NOVARTIS PHARMACEUTICALS CORPORATION v.                      7
 TORRENT PHARMA INC.


 Those cases were consolidated in multidistrict litigation in
 Delaware and proceeded to discovery.
                   A. Claim Construction
     At claim construction, the parties disputed only a
 single term of the ’659 patent: “wherein said [valsartan and
 sacubitril] are administered in combination.” See In re
 Entresto (Sacubitril/Valsartan) Pat. Litig., No. 20-md-
 2930, 
2021 WL 2856683
, at *3 (D. Del. July 8, 2021)
 (“Claim Construction Decision”) (emphasis added). MSN
 argued that the term limited the claim to administration of
 the active agents valsartan and sacubitril “as two separate
 components.” 
Id.
 As context for that position, according to
 MSN, the accused generic product, like Entresto, comprises
 a complex of non-covalently bonded valsartan and
 sacubitril. MSN Br. 1. Accordingly, if the claims were read
 to require the valsartan and sacubitril to be administered
 as separate components (i.e., in a non-complexed form,
 such as a physical mixture), then MSN’s generic product
 would not infringe the ’659 patent. For its part, Novartis
 argued that the claim was not so limited, and that the term
 should be given its plain and ordinary meaning. See Claim
 Construction Decision, at *3.
     The district court agreed with Novartis and gave the
 term its plain and ordinary meaning: “wherein said
 [valsartan and sacubitril] are administered in
 combination.” 
Id.
 In rejecting MSN’s proposal, the court
 observed that the intrinsic record “is silent on whether
 sacubitril and valsartan must be separate (and not
 complexed).” 
Id.
 It explained that “the absence of any
 indication in the written description that the patentee
 limited its invention solely to separate compounds means,
 in context, that a person of ordinary skill in the art [] would
 not read the claims as so limited.” 
Id.
 The court found that
 the representations Novartis had made to the U.S. Patent
 and Trademark Office (“the Patent Office”) to obtain PTE
 further bolstered that conclusion.         
Id.
    Specifically,
 Novartis told the Patent Office that the claims of the ’659
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 8                NOVARTIS PHARMACEUTICALS CORPORATION v.
                                     TORRENT PHARMA INC.


 patent recite compositions that include Entresto, a drug
 that includes “non-separate, complexed valsartan and
 sacubitril.” Id.; see Novartis Br. 16. The court found that
 a person of ordinary skill in the art would have given that
 evidence at least some weight in understanding the
 meaning of the disputed term.          Claim Construction
 Decision, at *3.
     Based in part on those representations to the Patent
 Office, MSN argued that Novartis’s position—that the
 plain and ordinary meaning of the claim scope
 encompasses     valsartan-sacubitril       complexes—would
 render the claims invalid for lack of written description and
 enablement because the specification nowhere describes
 such complexes. Id. at *4. The court rejected this
 argument, finding “no basis to believe that the construction
 [the court] adopt[ed was] necessarily consigning the
 asserted claims to a judgment of invalidity.” Id. After
 claim construction, MSN stipulated to infringement of the
 asserted claims. Decision, at *1.
                       B. Bench Trial
     The case proceeded to a three-day bench trial on the
 issues of obviousness, lack of written description, and non-
 enablement.3 Id.
                       1. Obviousness
     At trial, MSN set forth two theories of obviousness.
 First, it argued that a person of ordinary skill in the art
 would have been motivated to modify a prior art ARB-NEP
 inhibitor combination therapy—specifically, one using the


     3   MSN also argued the claims were invalid as
 indefinite. Finding that MSN raised that argument only in
 a footnote of its opening post-trial brief, the district court
 deemed the argument forfeited. Id. at *22. Neither party
 addresses indefiniteness on appeal, so we too do not
 consider it.
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 NOVARTIS PHARMACEUTICALS CORPORATION v.                   9
 TORRENT PHARMA INC.


 ARB irbesartan and an NEP inhibitor named
 “SQ 28,603”—with valsartan and sacubitril to arrive at the
 claimed invention. Id. at *10. Alternatively, MSN argued
 that a person of ordinary skill in the art would have been
 motivated to individually select and combine sacubitril and
 valsartan from two different prior-art references to arrive
 at the claimed invention. Id. The court was unpersuaded
 by both theories.
     Although the court found persuasive MSN’s argument
 that a person of ordinary skill in the art would have
 understood “that the combination of an ARB (irbesartan)
 and a NEP[ inhibitor] (SQ 28,603) achieved synergistic
 results,” the court ultimately concluded that, even if a
 person of ordinary skill in the art would have been
 motivated to pursue an ARB-NEP inhibitor combination,
 MSN “fail[ed] to provide clear and convincing evidence that
 a [person of ordinary skill in the art] would have been
 motivated to select the ARB valsartan and the
 NEP[ inhibitor] sacubitril specifically.” Id. Indeed, the
 court found that, as of 2002, sacubitril “had never been
 administered to humans or tested in an animal model of
 hypertension and heart failure,” and that, of the NEP
 inhibitors that had been so tested, the results had been
 “discouraging.” Id.
     In rejecting MSN’s challenges, the court further noted
 that none of the prior art “combined valsartan with
 sacubitril, sacubitril with an ARB, or valsartan with a[n]
 NEP[ inhibitor].” Id. at *12. It also observed that neither
 valsartan nor sacubitril were considered promising
 treatments for cardiac conditions in 2002. Id. Most
 importantly, in the court’s view, was “the fact that a large
 number of hypertension and heart failure drugs and drug
 classes were known in 2002—including multiple ARBs and
 a myriad of NEP[ inhibitors]—with no clear hierarchy
 within the ARB and NEP[ inhibitor] classes and no
 available information pointing directly at the claimed
 valsartan-sacubitril combination.” Id. The court further
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  10              NOVARTIS PHARMACEUTICALS CORPORATION v.
                                     TORRENT PHARMA INC.


  rejected MSN’s “obvious-to-try” theory on the grounds that
  there was a “surfeit of potentialities with respect to drug
  combinations for heart failure and hypertension
  treatment,” such that MSN’s obviousness theory hinged on
  impermissible hindsight. Id. at *13.
      Accordingly, the court determined that MSN had not
  shown by clear and convincing evidence that the claims of
  the ’659 patent were invalid as obvious. Id.
          2. Written Description and Enablement
      The court then turned to the issues of written
  description and enablement. Guided by the understanding
  that the court had “construed the asserted claims to cover
  valsartan and sacubitril as a physical combination and as
  a complex,” id. at *17, the parties’ dispute centered on
  whether the ’659 patent was required to enable and
  describe such complexes. MSN argued that it was, since a
  patent must enable and describe the full scope of the
  claims. E.g., id. at *17, *21. Novartis disagreed, arguing
  that a complex of valsartan and sacubitril was an after-
  arising invention that need not have been enabled or
  described. E.g., id. at *18–19. More specifically, Novartis
  contended that its “later, nonobvious discovery of valsartan
  and sacubitril in the form of a complex should not
  invalidate the ’659 patent claims to Novartis’s earlier
  invention: the novel combination of valsartan and
  sacubitril.” J.A. 4219. The court agreed with Novartis on
  the issue of enablement, but with MSN on the issue of
  written description.
      With respect to enablement, the court determined that,
  because enablement is judged as of the priority date, later-
  existing state of the art may not be properly considered in
  the enablement analysis. Decision, at *19 (relying on In re
  Hogan, 
559 F.2d 595
 (CCPA 1977); Plant Genetic Sys., N.V.
  v. DeKalb Genetics Corp., 
315 F.3d 1335
 (Fed. Cir. 2003);
  Chiron Corp. v. Genentech, Inc., 
363 F.3d 1247
 (Fed. Cir.
  2004)). And because complexes of valsartan and sacubitril
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  NOVARTIS PHARMACEUTICALS CORPORATION v.                     11
  TORRENT PHARMA INC.


  were unknown in the art in 2002, the court determined that
  they need not have been enabled in the ’659 patent. Id. at
  *20. The court further found that MSN had failed to
  establish that pharmaceutical complexes, more generally,
  were known or were nascent technology as of the 2002
  priority date. Id. at *20–21. Accordingly, the court
  determined that MSN had failed to establish that the
  claims of the ’659 patent were invalid for lack of
  enablement.
      The court reached the opposite conclusion with respect
  to written description. Relying primarily on Chiron, the
  court found that “the facts that helped [Novartis] with
  respect to enablement proved fatal for written description.”
  Id. at *21. Specifically, because it was undisputed that
  complexes were unknown to a person of ordinary skill in
  the art, “‘[Novartis] scientists, by definition, could not have
  possession of, and disclose, the subject matter of [such
  complexes]’ in 2002, and therefore, ‘axiomatically,
  [Novartis] cannot satisfy the written description
  requirement’ for such complexes.” Id. at *22 (quoting
  Chiron, 
363 F.3d at 1255
 (first and second alteration in
  original)). Thus, the court found the claims invalid for lack
  of written description and entered judgment on that basis.
     Novartis timely appealed. We have jurisdiction under
  
28 U.S.C. § 1295
(a)(1).
                           DISCUSSION
      Novartis challenges the district court’s findings on
  written description. MSN counters that, even if the claims
  are supported by adequate written description, the
  judgment of invalidity should be affirmed by reversing the
  district court’s determinations on obviousness and
  enablement. We address each issue in turn.
                                I
      We begin with written description. The issue on appeal
  is whether the ’659 patent describes what is claimed, viz.,
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  12               NOVARTIS PHARMACEUTICALS CORPORATION v.
                                      TORRENT PHARMA INC.


  a pharmaceutical composition comprising valsartan and
  sacubitril administered “in combination.” The issue is not
  whether the ’659 patent describes valsartan-sacubitril
  complexes. Because the ’659 patent does not claim
  valsartan-sacubitril complexes, those complexes need not
  have been described.
      As we have long recognized, “[t]he invention is, for
  purposes of the ‘written description’ inquiry, whatever is
  now claimed.” Vas-Cath Inc. v. Mahurkar, 
935 F.2d 1555, 1564
 (Fed. Cir. 1991). “A specification adequately describes
  an invention when it ‘reasonably conveys to those skilled
  in the art that the inventor had possession of the claimed
  subject matter as of the filing date.’” Juno Therapeutics,
  Inc. v. Kite Pharma, Inc., 
10 F.4th 1330, 1335
 (Fed. Cir.
  2021) (quoting Ariad Pharms. Inc. v. Eli Lilly & Co.,
  
598 F.3d 1336, 1351
 (Fed. Cir. 2010) (en banc)). The scope
  of what is claimed (and must be adequately described) is,
  in turn, determined through claim construction. Phillips
  v. AWH Corp., 
415 F.3d 1303, 1312
 (Fed. Cir. 2005) (en
  banc) (“It is a bedrock principle of patent law that the
  claims of a patent define the invention to which the
  patentee is entitled a right to exclude.” (internal quotation
  marks and citation omitted)).
      Recall that, at claim construction, MSN sought—as
  accused infringers often do—a construction that would
  exclude from infringement the accused product:
  a valsartan-sacubitril complex.     The court ultimately
  rejected MSN’s proposed construction because the ’659
  patent “is silent on whether sacubitril and valsartan must
  be separate (and not complexed).” Claim Construction
  Decision, at *3. The term was therefore given its plain and
  ordinary meaning: “wherein said [valsartan and sacubitril]
  are administered in combination.” 
Id.
      That invention is plainly described throughout the
  specification. For example, the opening sentence of the
  detailed description provides that “the present invention
  relates to pharmaceutical combinations comprising
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  TORRENT PHARMA INC.


  valsartan . . . and a NEP inhibitor . . . and pharmaceutical
  compositions comprising them.” ’659 patent col. 3 ll. 20–25
  (emphases added); see also 
id.
 col. 6 ll. 65–67 (“It can be
  shown that combination therapy with valsartan and a NEP
  inhibitor results in a more effective anti-hypertensive
  therapy[.]” (emphasis added)). The patent further specifies
  that the NEP inhibitor used in combination with valsartan
  can be sacubitril. 
Id.
 col. 7 ll. 33–36 (“Representative
  studies are carried out with a combination of valsartan and
  [sacubitril.]” (emphasis added)). And it further teaches
  that “[a] therapeutically effective amount of each of the
  component[s] of the combination of the present invention
  may be administered simultaneously or sequentially in any
  order.” 
Id.
 col. 10 ll. 57–59 (emphasis added). Those
  disclosures (and more) plainly show that the inventors had
  possession of a pharmaceutical composition comprising
  valsartan and sacubitril administered “in combination.”
  Indeed, even MSN’s expert conceded that the ’659 patent
  adequately discloses administration of valsartan and
  sacubitril in combination as a physical mixture. See J.A.
  3322. Thus, the claims are supported by an adequate
  written description.4
       The fact that the ’659 patent does not describe a
  complexed form of valsartan and sacubitril does not affect
  the validity of the patent.             That complex—not
  discovered until four years after the priority date of the ’659
  patent—is not what is claimed. By stating that the claims
  were “construed to cover complexes of valsartan and
  sacubitril,” the district court erroneously conflated the
  distinct issues of patentability and infringement, which led
  it astray in evaluating written description. Decision, at *15
  (emphasis added). Written description asks whether that


      4   MSN does not argue that the other limitations of
  the asserted claims are not adequately described.
  Accordingly, we focus our inquiry on only the disputed
  claim term: “in combination.”
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  14                NOVARTIS PHARMACEUTICALS CORPORATION v.
                                       TORRENT PHARMA INC.


  which is claimed is adequately described.       As we have
  explained:
       [C]laims are not construed “to cover” or “not to
       cover” the accused [product]. That procedure
       would make infringement a matter of judicial
       whim. It is only after the claims have been
       construed without reference to the accused device
       that the claims, as so construed, are applied to the
       accused device to determine infringement.
  SRI Int’l, 775 F.2d at 1118.
      Here, after claim construction, MSN stipulated to
  infringement of the as-construed claims.5 In light of that
  stipulation and the fact that the ’659 patent does not claim
  valsartan-sacubitril complexes, any further issue
  regarding such complexes is not before us.
      For those reasons, we hold that the district court
  clearly erred in finding that claims 1–4 of the ’659 patent
  are invalid for lack of written description. The patent has
  an adequate written description of what is claimed.




       5  To the extent MSN maintains that the claims were
  construed to claim valsartan-sacubitril complexes (i.e., to
  the extent MSN alleges that its stipulation of infringement
  was made on that basis), that construction would have
  been error. “Claim interpretation requires the court to
  ascertain the meaning of the claim to one of ordinary skill
  in the art at the time of invention.” SmithKline Beecham
  Corp. v. Apotex Corp., 
403 F.3d 1331, 1338
 (Fed. Cir. 2005)
  (emphasis added); see Phillips, 
415 F.3d at 1313
. Because
  valsartan-sacubitril    complexes     were     undisputedly
  unknown at the time of the invention, see Decision, at *20,
  the ’659 patent could not have been construed as claiming
  those complexes as a matter of law.
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  TORRENT PHARMA INC.


                                II
      We     affirm   the   district   court’s  enablement
  determination for reasons similar to those that led us to
  reverse its written description determination: a
  specification must only enable the claimed invention. See
  Amgen v. Sanofi, 
598 U.S. 594
, 610 (2023).
      The invention of the ’659 patent, as construed by the
  district court, is a composition in which valsartan and
  sacubitril are administered “in combination.” As explained
  above, the patent does not claim as its invention valsartan-
  sacubitril complexes. Indeed, Novartis obtained separate,
  later patents to such complexes. See Claim Construction
  Decision, at *1 (noting that “[s]everal years” after filing the
  ’659 patent, “Novartis developed a novel compound
  comprising non-covalently bound valsartan and sacubitril
  salts,” which are disclosed in U.S. Patents 8,877,938 and
  9,388,134).
      The district court correctly recognized that valsartan-
  sacubitril complexes, which include the claimed invention
  along with additional unclaimed features, are part of a
  “later-existing state of the art” that “may not be properly
  considered in the enablement analysis.” Decision, at *19;
  see In re Hogan, 
559 F.2d 595, 606
 (CCPA 1977) (holding
  that enablement must be judged in light of the state of the
  art at the time of filing); Plant Genetic, 
315 F.3d at 1340
  (“[O]ne [can]not use a later-existing state of the art to
  invalidate a patent that was enabled for what it claimed at
  the time of filing.”). As our predecessor court explained:
      The use of a subsequently-existing improvement to
      show lack of enablement in an earlier-filed
      application on the basic invention would preclude
      issuance of a patent to the inventor of the thing
      improved, and in the case of issued patents, would
      invalidate all claims (even some “picture claims”)
      therein. Patents are and should be granted to later
      inventors upon unobvious improvements. Indeed,
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  16               NOVARTIS PHARMACEUTICALS CORPORATION v.
                                      TORRENT PHARMA INC.


       encouragement of improvements on prior
       inventions is a major contribution of the patent
       system and the vast majority of patents are issued
       on improvements. It is quite another thing,
       however, to utilize the patenting or publication of
       later existing improvements to “reach back” and
       preclude or invalidate a patent on the underlying
       invention.
  Hogan, 
559 F.2d at 606
. That is precisely the case here.
  The later-discovered valsartan-sacubitril complexes, which
  arguably may have improved upon the “basic” or
  “underlying” invention claimed in the ’659 patent, cannot
  be used to “reach back” and invalidate the asserted claims.
      Thus, because the ’659 patent does not expressly claim
  complexes, and because the parties do not otherwise
  dispute that the ’659 patent enables that which it does
  claim, we affirm the district court’s determination that
  MSN failed to show that the claims are invalid for lack of
  enablement.
                               III
      Finally, we turn to obviousness. “Obviousness is a
  question of law based on underlying findings of fact.”
  Adapt Pharma Operations Ltd. v. Teva Pharms. USA, Inc.,
  
25 F.4th 1354, 1364
 (Fed. Cir. 2022) (citations omitted).
  Whether a person of ordinary skill in the art would have
  been motivated to combine the prior-art references to
  arrive at the claimed invention is a factual question we
  review for clear error. 
Id.
      We see no clear error warranting reversal of the district
  court’s obviousness analysis. The district court found that,
  even if a person of ordinary skill in the art had been
  motivated to provide an ARB-NEP inhibitor combination
  therapy, there was no motivation in the relied-upon prior
  art to combine valsartan and sacubitril, let alone with any
  reasonable expectation of success. As of 2002, sacubitril
  was one of over 100 known NEP inhibitors, it had never
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  TORRENT PHARMA INC.


  been administered to humans or animals, and the clinical
  results of other NEP inhibitors in hypertension and heart
  failure patients had been “discouraging.” See Decision, at
  *7.
      Those facts, as the district court acknowledged,
  distinguish this case from Nalproprion Pharmaceuticals,
  Inc. v. Actavis Laboratories FL, Inc., 
934 F.3d 1344
 (Fed.
  Cir. 2019), and BTG International Ltd. v. Amneal
  Pharmaceuticals LLC, 
923 F.3d 1063
 (Fed. Cir. 2019), on
  which MSN relies. In each of those cases, the prior art
  showed that the claimed drugs “were both together and
  individually considered promising . . . treatments at the
  time [of the invention].” BTG, 
923 F.3d at 1074
; see
  Nalproprion Pharms., 
934 F.3d at 1354
 (concluding that,
  because the prior art taught that each drug could cause
  weight loss effects, “a person of ordinary skill would have
  been motivated to combine them” to promote weight loss).
  That is not the case here, at least with respect to sacubitril.
  We therefore agree with the district court that MSN’s
  obviousness theories impermissibly use valsartan and
  sacubitril as a starting point and “retrace[] the path of the
  inventor with hindsight.”        Decision, at *13 (citation
  omitted).
      Accordingly, because we see no errors in the district
  court’s factual findings or application of the law, we affirm
  the district court’s determination that MSN failed to
  establish that the claims would have been obvious.
                          CONCLUSION
      We have considered the parties’ remaining arguments
  and find them unpersuasive. For the foregoing reasons, we
  reverse the district court’s finding that the claims lack
  adequate written description, and we affirm its
  determinations that the claims were not shown to have
  been obvious or non-enabled.
       AFFIRMED IN PART, REVERSED IN PART
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  18              NOVARTIS PHARMACEUTICALS CORPORATION v.
                                     TORRENT PHARMA INC.


                          COSTS
  Costs to Novartis.