In re: Entresto (sacubitril/valsartan)… v. Torrent Pharma Inc., Torrent Pharmaceuticals Ltd.

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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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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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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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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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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(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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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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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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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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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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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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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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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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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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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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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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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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COSTS
Costs to Novartis.
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