  United States Court of Appeals
      for the Federal Circuit
                ______________________

    NUVO PHARMACEUTICALS (IRELAND)
  DESIGNATED ACTIVITY COMPANY, HORIZON
             MEDICINES LLC,
          Plaintiffs-Cross-Appellants

                           v.

DR. REDDY’S LABORATORIES INC., DR. REDDY’S
 LABORATORIES, LTD., MYLAN, INC., MYLAN
      PHARMACEUTICALS INC., MYLAN
         LABORATORIES LIMITED,
             Defendants-Appellants

 LUPIN LTD., LUPIN PHARMACEUTICALS, INC.,
              Defendants-Appellees
             ______________________

2017-2473, 2017-2481, 2017-2484, 2017-2486, 2017-2489,
           2017-2491, 2017-2492, 2017-2493
               ______________________

    Appeals from the United States District Court for the
District of New Jersey in Nos. 3:11-cv-02317-MLC-DEA,
3:13-cv-00091-MLC-DEA, 3:13-cv-04022-MLC-DEA, Judge
Mary L. Cooper.
                ______________________

                Decided: May 15, 2019
                ______________________

   JAMES B. MONROE, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, Washington, DC, argued for
2        NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




plaintiffs-cross-appellants. Plaintiff-cross-appellant Hori-
zon Medicines LLC also represented by CHARLES COLLINS-
CHASE.

    STEPHEN M. HASH, Baker Botts, LLP, Austin, TX, for
plaintiff-cross-appellant Nuvo Pharmaceuticals (Ireland)
Designated Activity Company.       Also represented by
JEFFREY SEAN GRITTON.

    ALAN HENRY POLLACK, Windels Marx Lane & Mitten-
dorf LLP, Madison, NJ, argued for all defendants-appel-
lants. Defendants-appellants Dr. Reddy's Laboratories
Inc., Dr. Reddy's Laboratories, Ltd. also represented by
STUART D. SENDER.

    ANDREW DUFRESNE, Perkins Coie LLP, Madison, WI,
argued for all defendants-appellants. Defendants-appel-
lants Mylan, Inc., Mylan Pharmaceuticals Inc., Mylan La-
boratories Limited also represented by AUTUMN N. NERO;
DAN L. BAGATELL, Hanover, NH; SHANNON BLOODWORTH,
Washington, DC.

     SAILESH K. PATEL, Schiff Hardin LLP, Chicago, IL, for
defendants-appellees Lupin Ltd., Lupin Pharmaceuticals,
Inc.
                 ______________________

    Before PROST, Chief Judge, CLEVENGER and WALLACH,
                       Circuit Judges.
CLEVENGER, Circuit Judge.
     Dr. Reddy’s Laboratories, Inc., Mylan Pharmaceuti-
cals, and Lupin Pharmaceuticals (collectively, “the Gener-
ics”) appeal from the final judgment of the United States
District Court for the District of New Jersey following a
bench trial upholding the asserted claims of U.S. Patent
Nos. 6,926,907 (“the ’907 patent”) and 8,557,285 (“the ’285
patent”) as nonobvious under 35 U.S.C. § 103, enabled
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES           3



under 35 U.S.C. § 112, and adequately described under
§ 112. Nuvo Pharmaceuticals, Inc. and Horizon Pharma
(collectively, “Nuvo”) cross-appeal from the district court’s
grant of summary judgment of noninfringement to Dr.
Reddy’s, concluding that one of its drug products will not
infringe the claims of the ’907 patent. For the reasons set
forth below, we reverse the appeal and dismiss the cross-
appeal.
                       BACKGROUND
                              I
    Non-steroidal anti-inflammatory drugs, also known as
NSAIDs, control pain. Common NSAIDs include, among
others, aspirin and naproxen. While NSAIDs control pain,
they also have the undesirable side effect of causing gas-
trointestinal problems such as ulcers, erosions, and other
lesions in the stomach and upper small intestine. Some
theorize that the undesirable side effect is tied to the com-
bination of NSAID with the presence of acid in the stomach
and upper small intestine. So, to treat the side effect, some
practitioners began prescribing acid inhibitors to be taken
by a patient along with the NSAID. The NSAID treats the
pain while the acid inhibitor reduces the acidity in the gas-
trointestinal tract, which is achieved by increasing the pH
level in the tract. Common acid inhibitors include, among
others, proton pump inhibitors (“PPIs”) like omeprazole
and esomeprazole.
    The combination therapy had complications. First,
stomach acid degraded the PPI before it could reach the
small intestine. To fix that issue, an enteric coating that
wears off after a certain amount of time has elapsed was
placed around the PPI. Second, if the NSAID was released
before the acid inhibitor had enough time to raise the pH
level in the tract, patients would continue to suffer gastro-
intestinal damage. To address those complications, Dr.
John Plachetka invented a new drug form that coordinated
the release of an acid inhibitor and an NSAID in a single
4       NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




tablet. The tablet contained a core of an NSAID like
naproxen in an amount effective to treat pain, an enteric
coating around the NSAID that prevents its release before
the pH increases to a certain desired level, and an acid in-
hibitor like PPI around the outside of the enteric coating
that actively works to increase the pH to the desired level.
Dr. Plachetka’s invention contemplates using some
amount of uncoated PPI to allow for its immediate release
into a patient’s stomach and upper small intestine. Dr.
Plachetka recognized problems associated with uncoated
PPI, namely that without a coating, the PPI is at risk of
destruction by stomach acid—thereby undermining the
therapeutic effectiveness of the PPI.
    Dr. Plachetka received the ’907 patent on his invention,
which he assigned to Pozen Inc. He also received the ’285
patent, which is a division of an abandoned application
that was a division of another application that itself was a
continuation-in-part of the application that resulted in the
’907 patent. The ’285 patent is also assigned to Pozen. The
two patents bear the same title, “Pharmaceutical Composi-
tions for the Coordinated Delivery of NSAIDs,” and have
nearly identical specifications.
    Claim 1 of the ’907 patent and claim 1 of the ’285 patent
are representative. They read as follows:
    1. A pharmaceutical composition in unit dosage
    form suitable for oral administration to a patient,
    comprising:
        (a) an acid inhibitor present in an amount
        effective to raise the gastric pH of said pa-
        tient to at least 3.5 upon the administra-
        tion of one or more of said unit dosage
        forms;
        (b) a non-steroidal anti-inflammatory drug
        (NSAID) in an amount effective to reduce
        or eliminate pain or inflammation in said
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES          5



        patient upon administration of one or more
        of said unit dosage forms;
    and wherein said unit dosage form provides for co-
    ordinated release such that:
        i) said NSAID is surrounded by a coating
        that, upon ingestion of said unit dosage
        form by said patient, prevents the release
        of essentially any NSAID from said dosage
        form unless the pH of the surrounding me-
        dium is 3.5 or higher;
        ii) at least a portion of said acid inhibitor
        is not surrounded by an enteric coating
        and, upon ingestion of said unit dosage
        form by said patient, is released regardless
        of whether the pH of the surrounding me-
        dium is below 3.5 or above 3.5.
’907 patent col. 20 ll. 9–32.
    1. A pharmaceutical composition in unit dosage
    form comprising therapeutically effective amounts
    of:
        (a) esomeprazole, wherein at least a por-
        tion of said esomeprazole is not surrounded
        by an enteric coating; and
        (b) naproxen surrounded by a coating that
        inhibits its release from said unit dosage
        form unless said dosage form is in a me-
        dium with a pH of 3.5 or higher;
    wherein said unit dosage form provides for release
    of said esomeprazole such that upon introduction
    of said unit dosage form into a medium, at least a
    portion of said esomeprazole is released regardless
    of the pH of the medium.
’285 patent col. 22 ll. 9–19.
6        NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




    The shared specification discloses that the invention “is
directed to a pharmaceutical composition in unit dosage
form suitable for oral administration to a patient” that
“contains an acid inhibitor present in an amount effective
to raise the gastric pH of a patient to at least 3.5, preferably
to at least 4, and more preferably to at least 5, when one or
more unit dosage forms are administered.” ’907 patent col.
3 ll. 19–25. 1 It discloses exemplary acid inhibitors like
PPIs, which the patents teach includes omeprazole and
esomeprazole. It recites amounts of omeprazole between 5
and 50 mg and amounts of esomeprazole between 5 and 100
mg, “with about 40 mg per unit dosage form being pre-
ferred.” Id. at col. 7 ll. 9–13. The specification discloses
that “[t]he pharmaceutical composition also contains a non-
steroidal anti-inflammatory drug in an amount effective to
reduce or eliminate pain or inflammation.” Id. at col. 3 ll.
39–41. It provides that “[t]he most preferred NSAID is
naproxen in an amount of between 50 mg and 1500 mg, and
more preferably, in an amount of between 200 mg and 600
mg.” Id. at col. 3 ll. 48–50.
    The specification teaches methods for preparing and
making the claimed drug formulations, including in tablet
dosage forms. It provides examples of the structure and
ingredients of the drug formulations that comport with the
invention. It is undisputed that there is no experimental
data demonstrating the therapeutic effectiveness of any
amount of uncoated PPI and coated NSAID in a single dos-
age form. Appellant’s Opening Br. 23, 33; Appellee’s Resp.
Br. 35, 43; Oral Arg. at 34:08–40, http://oralargu-
ments.cafc.uscourts.gov/default.aspx?fl=2017-2473.mp3.
Furthermore, although the specification expressly provides
that PPIs are “enteric coated to avoid destruction by



    1   Because the ’907 and ’285 patents have nearly
identical specifications, we cite to the ’907 patent only un-
less stated otherwise.
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES            7



stomach acid,” there is no alternative disclosure explaining
that uncoated PPI could still be effective to raise pH. ’907
patent col. 2 l.6; Oral Arg. at 34:08–39:28.
    Pozen ultimately sold its rights to the ’907 and ’285 pa-
tents to Nuvo Pharmaceuticals, and Horizon Pharma
maintained its previously obtained license under those pa-
tents. Nuvo makes and sells a drug called Vimovo®, which
is a commercial embodiment of the ’907 and ’285 patents.
The Generics want to market a generic version of Vimovo®.
They submitted Abbreviated New Drug Applications (“AN-
DAs”) to the U.S. Food and Drug Administration (“FDA”)
seeking approval to market products covered by the claims
of the ’907 and ’285 patents. Dr. Reddy’s also submitted a
second ANDA covering a product slightly different than
Vimovo® because it contains a small amount of uncoated
NSAID in the outer layer of the tablet, which is separate
from the enteric-coated NSAID that releases only when the
pH rises to about 5.5.
                              II
    Nuvo sued the Generics in the United States District
Court for the District of New Jersey to prevent their ANDA
products from going to market, if approved, before the ex-
piration of the ’907 and ’285 patents. Nuvo alleged that all
the Generics’ ANDA products will infringe claims 5, 15, 52,
and 53 of the ’907 patent and claims 1–4 of the ’285 patent. 2
The Generics stipulated to infringement, except with re-
spect to Dr. Reddy’s second ANDA product, which it alleged
will not infringe the claims of either patent. The Generics
defended against the infringement assertions by alleging
that the asserted patents are invalid as obvious over the
prior art under 35 U.S.C. § 103 and for lack of enablement
and an adequate written description under 35 U.S.C. § 112.



    2  All the asserted claims of the ’907 and ’285 patents
are dependent on claim 1 of those respective patents.
8       NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




     Dr. Reddy’s moved for summary judgment of nonin-
fringement, arguing that its second ANDA product does not
infringe the asserted claims of the ’907 patent. It argued
that, because the claims of the ’907 patent prevent “essen-
tially any NSAID” from being released from the unit dos-
age form until the pH reaches at least 3.5, its second ANDA
product containing some amount of NSAID in the outer
layer that is released immediately, regardless of the pH,
cannot infringe those claims. Nuvo countered that the
phrase “essentially any NSAID” in the claim language pre-
vents only NSAID in the core of the tablet from being re-
leased before the pH rises to 3.5 or higher and that the
claimed invention allows for a small amount of additional
NSAID to be released immediately. The district court
agreed with Dr. Reddy’s and granted its summary judg-
ment motion.
    The court then held a six-day bench trial on the validity
of the ’907 and ’285 patents, as well as Dr. Reddy’s conten-
tion that its second ANDA product does not infringe the
asserted claims of the ’285 patent. It concluded that none
of the asserted claims are obvious over the prior art be-
cause it was nonobvious to use a PPI to prevent NSAID-
related gastric injury, and persons of ordinary skill in the
art were discouraged by the prior art from using uncoated
PPI and would not have reasonably expected it to work. It
also determined that the asserted claims of both patents
are enabled because the specification teaches how to make
and use the invention and expert testimony demonstrated
that an ordinarily skilled artisan would have accepted the
usefulness of an NSAID–PPI combination therapy for
treating pain.
    The district court went on to reject all three of the Ge-
nerics’ written description arguments. First, the court re-
jected the “comprising” written description argument. The
Generics argued that, because of the “comprising” lan-
guage in the ’285 patent’s claims, they allow for the drug
formulation to include some uncoated naproxen that is
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES           9



released immediately regardless of the pH, which is not
supported by the specification and goes against the concept
of coordinated release that is at the heart of the patent’s
invention. The court disagreed because it viewed uncoated
naproxen as a less preferred embodiment of the claimed in-
vention and thus found that the invention was supported
by the general disclosure in the specification.
    Second, the district court rejected the “inhibit” written
description argument. The Generics contended that, alt-
hough the patent discloses only delayed release formula-
tions, the claims of the ’285 patent recite a broader
undescribed invention, namely sustained release as op-
posed to coordinated release of naproxen. That is because
the claims cover any formulation having a coating that
merely “inhibits” the release of naproxen before the pH
reaches 3.5 or higher, which would include sustained re-
lease drugs that immediately discharge naproxen albeit at
a slower rate than is typical. The court disagreed that the
word “inhibits” meant that the claims contemplated sus-
tained release drug formulations and thus concluded that
the claims do not lack written description support on that
basis.
    Third, the district court rejected the “efficacy” written
description argument. The Generics argued that, if they
lose on their obviousness contention, then the claims lack
written description support for the claimed effectiveness of
uncoated PPI because ordinarily skilled artisans would not
have expected it to work and the specification provides no
experimental data or analytical reasoning showing the in-
ventor possessed an effective uncoated PPI. Nuvo re-
sponded that experimental data and an explanation of why
an invention works are not required, the specification ade-
quately describes using uncoated PPI, and its effectiveness
is necessarily inherent in the described formulation. The
court rejected the notion that effectiveness does not need to
be described because it is necessarily inherent in the
claimed drug formulation.          It also held that the
10      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




specification of the ’907 and ’285 patents did not disclose
information regarding the efficacy of uncoated PPI. But
the court nonetheless concluded that the claims were ade-
quately described because the specification described the
immediate release of uncoated PPI and the potential dis-
advantages of coated PPI, namely that enteric-coated PPI
sometimes works too slowly to raise the intragastric pH.
The district court did not explain why the mere disclosure
of immediate release uncoated PPI, coupled with the
known disadvantages of coated PPI, is relevant to the ther-
apeutic effectiveness of uncoated PPI, which the patent it-
self recognized as problematic for efficacy due to its
potential for destruction by stomach acid.
   Finally, the district court held that Dr. Reddy’s second
ANDA product infringes the claims of the ’285 patent be-
cause it satisfies all the limitations recited in those claims.
    The Generics now appeal the first “comprising” and
third “efficacy” written description rulings. They do not ap-
peal the obviousness holding, the enablement decision, or
the second “inhibit” written description issue. Nuvo cross-
appeals the district court’s grant of summary judgment of
noninfringement. We have jurisdiction to decide the ap-
peals under 28 U.S.C. § 1295(a)(1).
                         DISCUSSION
     The Generics’ appeal and Nuvo’s cross-appeal present
three main issues. First, the Generics argue that the dis-
trict court clearly erred when it concluded that the specifi-
cation of the ’907 and ’285 patents adequately describes the
claimed effectiveness of uncoated PPI. The Generics em-
phasize the circumstances in which the written description
issue arises in this case. The asserted claims recite the
therapeutic effectiveness of uncoated PPI, but the prior art
taught away from such effectiveness. In those circum-
stances, the Generics argue that satisfaction of the written
description requirement requires either supporting experi-
mental data, or some reason, theory, or alternative
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES           11



explanation as to why the claimed invention is possessed
by the inventor, and that mere recitation of claim language
in the specification cannot suffice. Second, the Generics
argue that the district court clearly erred when it con-
cluded that the specification of the ’907 and ’285 patents
adequately describes uncoated naproxen. Finally, Nuvo ar-
gues that the district court should not have granted sum-
mary judgment of noninfringement in favor of Dr. Reddy’s
because it incorrectly construed the term “essentially any
NSAID” in the claims of the ’907 patent to prevent even
small amounts of uncoated NSAID in the unit dosage form.
    Whether a claim satisfies the written description re-
quirement is a question of fact. Allergan, Inc. v. Sandoz
Inc., 796 F.3d 1293, 1308 (Fed. Cir. 2015). Therefore, on
appeal from a bench trial, we review a written description
determination for clear error. Id. “Under the clear error
standard, the court’s findings will not be overturned in the
absence of a ‘definite and firm conviction’ that a mistake
has been made.” Scanner Techs. Corp. v. ICOS Vision Sys.
Corp. N.V., 528 F.3d 1365, 1374 (Fed. Cir. 2008) (quoting
Pfizer, Inc. v. Teva Pharm. USA, Inc., 518 F.3d 1353, 1366
(Fed. Cir. 2008)).
    Our analysis begins and ends with the “efficacy” writ-
ten description issue.
                              I
    The written description requirement of 35 U.S.C.
§ 112, ¶ 1 provides, in pertinent part, that “[t]he specifica-
tion shall contain a written description of the invention.” 3
That requirement is satisfied only if the inventor “convey[s]


    3    Because the applications resulting in the ’907 and
’285 patents were filed before the enactment of the Leahy–
Smith America Invents Act (“AIA”), Pub. L. No. 112–29,
§ 4(c), 125 Stat. 284, 296–97 (2011), we apply the pre-AIA
version of 35 U.S.C. § 112.
12      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




with reasonable clarity to those skilled in the art that, as
of the filing date sought, he or she was in possession of the
invention,’ and demonstrate[s] that by disclosure in the
specification of the patent.” Centocor Ortho Biotech, Inc. v.
Abbott Labs., 636 F.3d 1341, 1348 (Fed. Cir. 2011) (quoting
Carnegie Mellon Univ. v. Hoffmann–La Roche Inc., 541
F.3d 1115, 1122 (Fed. Cir. 2008)). “The essence of the writ-
ten description requirement is that a patent applicant, as
part of the bargain with the public, must describe his or her
invention so that the public will know what it is and that
he or she has truly made the claimed invention.” AbbVie
Deutschland GmbH & Co. v. Janssen Biotech, Inc., 759
F.3d 1285, 1298 (Fed. Cir. 2014).
     The Generics argue that the district court clearly erred
when it concluded that the claimed effectiveness of un-
coated PPI in the ’907 and ’285 patents is supported by ad-
equate written description.           Their argument is
straightforward. The ’907 and ’285 patents claim uncoated
PPI effective to raise the gastric pH to at least 3.5, the dis-
trict court found upon Nuvo’s insistence as part of its obvi-
ousness analysis that ordinarily skilled artisans would not
have expected uncoated PPIs to be effective, and nothing in
the specification would teach a person of ordinary skill in
the art otherwise.
    Nuvo counters that the district court correctly con-
cluded that the claimed uncoated PPI is supported by ade-
quate written description. It argues that the claims do not
require any particular degree of efficacy of the uncoated
PPI itself, it is enough that the specification discloses mak-
ing and using drug formulations containing effective
amounts of PPI and NSAID, and experimental data and
additional explanations demonstrating the invention
works are unnecessary.
    The district court held that the Generics failed to prove
by clear and convincing evidence that the asserted claims
of the ’907 and ’285 patents are invalid for lack of written
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES           13



description. But its analysis does not support its conclu-
sion. The district court, after finding that the specification
lacks “information regarding the efficacy of uncoated
PPIs,” said it was enough that the specification described
the immediate release of uncoated PPI and the potential
disadvantages of enteric-coated PPI formulations. J.A. 82–
83. But that disclosure it pointed to in no way provides
support for the claimed efficacy of uncoated PPI. Even if
the district court thought that it was enough that the pa-
tents taught how to make and use drug formulations con-
taining uncoated PPI, it flatly rejected Nuvo’s argument
“that the efficacy of uncoated PPIs need not be described
because it is ‘necessarily inherent’ in a formulation.” J.A.
83. Nevertheless, because we review the district court’s de-
cision for clear error, we will scour the record created below
for evidence supporting the district court’s written descrip-
tion finding.
                              A
     At trial, the parties and the district court understood
that the plain words of the patents claim effectiveness of
uncoated PPI. Beyond the plain language of the claims, the
district court was not asked to define further the effective-
ness limitation. The parties and the district court also un-
derstood that written description of effective uncoated PPI
is required. Nuvo nonetheless for the first time on appeal,
and as its lead argument, contends that we can affirm the
district court’s written description finding because the
claims do not recite an efficacy requirement for uncoated
PPI. The Generics of course disagree. We read Nuvo’s ap-
pellate brief as presenting at least five arguments aimed at
either recharacterizing the written description dispute or
rewriting the claim language. We reject them all as merit-
less.
    Claim 1 of the ’907 patent recites “[a] pharmaceutical
composition in unit dosage form suitable for oral admin-
istration to a patient, comprising: . . . an acid inhibitor
14      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




present in an amount effective to raise the gastric pH of said
patient to at least 3.5 upon the administration of one or
more of said unit dosage forms” and wherein “at least a
portion of said acid inhibitor is not surrounded by an en-
teric coating . . . .” ’907 patent col. 20 ll. 9–29 (emphasis
added). Claim 1 of the ’285 patent recites “[a] pharmaceu-
tical composition in unit dosage form comprising therapeu-
tically effective amounts of: (a) esomeprazole, wherein at
least a portion of said esomeprazole is not surrounded by
an enteric coating” and “wherein said unit dosage form pro-
vides for release of said esomeprazole such that upon intro-
duction of said unit dosage form into a medium, at least a
portion of said esomeprazole is released regardless of the
pH of the medium.” ’285 patent col. 22 ll. 9–19 (emphasis
added). The claim also recites “naproxen surrounded by a
coating that inhibits its release from said unit dosage form
unless said dosage form is in a medium with a pH of 3.5 or
higher,” which means the esomeprazole must be acting to
raise the pH to effect the release of the naproxen from the
dosage form. Id. at col. 22 ll. 13–15. Both patents-in-suit
therefore recite claims requiring amounts of uncoated PPI
effective to raise the gastric pH to at least 3.5. No argu-
ment was made below that the claims of the ’907 patent
should be treated any differently than those of the ’285 pa-
tent with respect to the efficacy limitation. And the district
court treated the claims the same with respect to that lim-
itation. So we do not treat them differently on appeal ei-
ther.
    First, Nuvo argues that there is no requirement that
the dosage form as a whole be effective to raise the gastric
pH. While we agree, we do not understand the Generics to
be arguing that the claims require the entire drug to be ef-
fective to raise the gastric pH to a certain level. Instead,
the uncoated PPI must effectively do so.
    Second, Nuvo contends that the claims do not require
an effective amount of the combined uncoated PPI and
coated naproxen in a single dosage form, but only amounts
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES            15



of each component effective on their own. The Generics re-
spond that Nuvo’s argument is divorced from the claim as
a whole, which requires coordinated release achieved by an
effective amount of uncoated PPI that raises the gastric pH
to at least 3.5 and an effective amount of naproxen that is
released to treat pain when the pH reaches the desired
level. Nuvo’s argument was not raised below and thus is
forfeited. See TVIIM, LLC v. McAfee, Inc., 851 F.3d 1356,
1363 (Fed. Cir. 2017) (“[A] party may not introduce new
claim construction arguments on appeal or alter the scope
of the claim construction positions it took below. Moreover,
litigants waive their right to present new claim construc-
tion disputes if they are raised for the first time after
trial.”).
    Third, Nuvo argues that the claims do not require that
the uncoated PPI be effective to raise the gastric pH to a
certain level, but only that the dosage forms contain an ef-
fective amount of uncoated PPI. The Generics disagree.
Nuvo forfeited the argument by not raising it below. Addi-
tionally, it is nonsensical to read the claims to require ef-
fective amounts of uncoated PPI without specifying the
result effectively achieved. Claim 1 of the ’907 patent ex-
pressly states that the PPI, which is uncoated, must be ef-
fective to raise the gastric pH to at least 3.5. Claim 1 of the
’285 patent at least impliedly requires the same since the
naproxen is only released when the pH reaches at least 3.5
and the uncoated esomeprazole is the only other agent
available in the dosage form to achieve that goal.
     Fourth, Nuvo contends that the ’907 patent allows mul-
tiple dosage forms rather than a single dosage form to sat-
isfy any perceived efficacy requirement, so the specification
does not need to show an effective amount of uncoated PPI
in one dosage form. We disagree. As stated above, Nuvo
forfeited any argument that the ’907 and ’285 patents
should be treated differently with respect to the efficacy re-
quirement by not raising it to the district court. And the
’285 patent does not allow for more than one dosage form.
16      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




Even if it were true that the ’907 patent allows more than
one dosage form to effectively raise the gastric pH to at
least 3.5 using uncoated PPI, the specification would still
need to provide support for the notion that uncoated PPI is
effective.
    Last, Nuvo argues that the Examiner interpreted the
’907 patent claims as merely requiring certain amounts of
PPI and NSAID effective on their own rather than requir-
ing an overall efficacy for the combined drug. The Generics
counter that the Examiner never considered the effective-
ness of uncoated PPI because it was not a claim limitation
at the time of the initial rejection. We already rejected
Nuvo’s argument that the difference between a dosage
form as a whole containing an effective amount of uncoated
PPI and an effective amount of uncoated PPI as a compo-
nent meaningfully impacts the written description analy-
sis. And we also already rejected its argument that the
Generics were contending that Nuvo had to demonstrate
the overall effectiveness of the entire drug combination.
Furthermore, the argument is forfeited because it was not
presented below. Finally, the Examiner appears to have
interpreted the claims to require an amount of PPI,
whether coated or uncoated, effective to raise the gastric
pH to the desired level. We agree with that understanding
and written description support must be provided for that
limitation.
    In sum, the parties appear to have assumed before the
district court that the claims require a therapeutically ef-
fective amount of uncoated PPI that can raise the gastric
pH to at least 3.5. We see no reason to change course on
appeal. Because the parties’ assumption at the trial court
is a fair reading of the claim language, we will proceed as
everyone did before the district court and search the speci-
fication for written description support for the efficacy of
uncoated PPI.
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES             17



                               B
    Nuvo argues that credible expert testimony from its
witness, Dr. Williams, identified written description sup-
port in the specification for the claimed dosage forms com-
prising an effective amount of uncoated PPI. Specifically,
Nuvo points to Dr. Williams’s testimony that every limita-
tion of the asserted claims in the ’907 and ’285 patents has
adequate written description support in the shared specifi-
cation.
     Dr. Williams identified four parts of the specification
that he thought provide written description support for
amounts of uncoated PPI, and specifically esomeprazole,
effective to raise the gastric pH of a patient to at least 3.5.
He pointed to the specification’s statement that “[t]he com-
position contains an acid inhibitor present in an amount
effective to raise the gastric pH of a patient to at least 3.5.”
See J.A. 10787 (quoting ’907 patent col. 3 ll. 21–23), 10797
(similar). He also pointed to the claims themselves for
written description support. See J.A. 10787 (citing ’907 pa-
tent col. 20 ll. 9–32, 42–45), 10798 (similar). He then said
the sixth example in the specification provides support for
uncoated PPI because it includes “omeprazole immediate
release” in the title and provides that a layer of the compo-
sition embodied in the example “contains an acid inhibitor
in an effective amount which is released from the dosage
form as soon as the film coat dissolves,” where the acid in-
hibitor is the PPI omeprazole. J.A. 10788–89 (quoting ’907
patent col. 14 ll. 40–41, col. 15 ll. 1–3). His last piece of
support from the specification was its statement that
“[p]roton pump inhibitors will typically be present at about
5 milligrams to 600 milligrams per dose” and “[e]somepra-
zole is 5 to 100 milligrams.” J.A. 10798 (quoting ’907 pa-
tent col. 7 ll. 7–13).
    The Generics argue that the parts of the specification
Dr. Williams identified are not enough to satisfy the writ-
ten description requirement.       They argue that the
18      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




specification provides only typical dosage amounts of un-
coated PPI and the use of uncoated PPI in a drug formula-
tion, but it never discusses or explains its efficacy. We
agree with the Generics that Dr. Williams’s testimony does
not identify parts of the specification sufficient to satisfy
the written description requirement. The statements he
points to recite the claim limitation by simply calling gen-
erally for effective amounts of uncoated PPI, but our prec-
edent clearly establishes that is not enough.
    We have expressly rejected the “argument that the
written description requirement . . . is necessarily met as a
matter of law because the claim language appears in ipsis
verbis in the specification.” Enzo Biochem, Inc. v. Gen–
Probe Inc., 323 F.3d 956, 968 (Fed. Cir. 2002). We ex-
plained that “[t]he appearance of mere indistinct words in
a specification or a claim, even an original claim, does not
necessarily satisfy” § 112, ¶ 1 because it may not both put
others on notice of the scope of the claimed invention and
demonstrate possession of that invention. Id. at 968–69.
    It is true that our case law does not require experi-
mental data demonstrating effectiveness. Allergan, 796
F.3d at 1309; see also In re ’318 Patent Infringement Litig.,
583 F.3d 1317, 1324 (Fed. Cir. 2009) (“Typically, patent ap-
plications claiming new methods of treatment are sup-
ported by test results. But it is clear that testing need not
be conducted by the inventor.”). It also does not require
theory or explanation of how or why a claimed composition
will be effective. Allergan, 796 F.3d at 1308–09. Moreover,
we have repeatedly stated that the invention does not ac-
tually have to be reduced to practice. Univ. of Rochester v.
G.D. Searle & Co., 358 F.3d 916, 926 (Fed. Cir. 2004).
    Nevertheless, as the Generics point out and Nuvo can-
not reasonably dispute, the record evidence demonstrates
that a person of ordinary skill in the art would not have
known or understood that uncoated PPI is effective. And
there is nothing in the specification of the patents-in-suit
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES            19



showing “that the inventor actually invented the invention
claimed.” Centocor, 636 F.3d at 1348 (emphasis added); ac-
cord Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336,
1351 (Fed. Cir. 2010) (en banc). There must be some de-
scription, such as a constructive reduction to practice, es-
tablishing that the inventor “was in possession of the . . .
claimed invention, including all of the elements and limi-
tations.” Univ. of Rochester, 358 F.3d at 926 (quoting Hyatt
v. Boone, 146 F.3d 1348, 1353 (Fed. Cir. 1998)). Patents
are not rewarded for mere searches, but are intended to
compensate their successful completion. Ariad, 598 F.3d
at 1353. That is why the written description requirement
incentivizes “actual invention,” id., and thus “[a] ‘mere
wish or plan’ for obtaining the claimed invention is not ad-
equate written description,” Centocor, 636 F.3d at 1348
(quoting Regents of the Univ. of Cal. v. Eli Lilly & Co., 119
F.3d 1559, 1566 (Fed. Cir. 1997)).
     In light of the fact that the specification provides noth-
ing more than the mere claim that uncoated PPI might
work, even though persons of ordinary skill in the art
would not have thought it would work, the specification is
fatally flawed. It does not demonstrate that the inventor
possessed more than a mere wish or hope that uncoated
PPI would work, and thus it does not demonstrate that he
actually invented what he claimed: an amount of uncoated
PPI that is effective to raise the gastric pH to at least 3.5.
That conclusion is confirmed by the inventor’s, Dr.
Plachetka’s, own testimony at trial during which he admit-
ted that he only had a “general concept of coordinated de-
livery with acid inhibition” using uncoated PPI at the time
he filed his first patent application. J.A. 9942, 10000–01.
Although Dr. Plachetka said he thought he “put a rationale
in [the specification] as to why [uncoated PPI] would work,”
he did not identify any particular part of the specification
supporting that understanding. J.A. 9997. And his only
support in the specification for “a rationale explaining why
[he] thought the uncoated PPI would be effective for
20       NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




treating gastric related injury” was that, in its “entire con-
text,” he explained “why the coordinated delivery system
would be of benefit for patients.” Id. Although inventor
testimony cannot establish written description support
where none exists in the four corners of the specification, it
illuminates the absence of critical description in this case. 4
                              C
    Nuvo’s final arguments are that it is enough to satisfy
the written description requirement that the specification
of the ’907 and ’285 patents teaches how to make and use
the claimed invention, and that we should accept the ther-
apeutic effectiveness of uncoated PPI as a matter of


     4   At oral argument, Nuvo also encouraged us to find
written description support for the therapeutic effective-
ness of uncoated PPI based on testimony of Dr. Kibbe, the
Generics’ expert. Oral Arg. at 50:51–52:26. But in that
part of the trial transcript Nuvo directed us to, Dr. Kibbe
only discussed what the patent claims require and he never
testified about the written description support in the spec-
ification for the efficacy of uncoated PPI. Furthermore, alt-
hough Dr. Kibbe later confirmed during his trial testimony
that he thought “an enteric-coated NSAID surrounded by
an uncoated PPI would be effective for treating chronic
pain,” his confirmation was ambiguous because he quali-
fied it with “I think I have got that right. I’m not sure.”
J.A. 10513. Even if we accepted his statement that un-
coated PPI would be effective for treating chronic pain, the
district court rejected the notion that ordinarily skilled ar-
tisans would have used uncoated PPI in its obviousness
analysis, and his testimony only speaks to treating pain
and not to raising the gastric pH to at least 3.5. Disposi-
tively, Dr. Kibbe’s testimony is irrelevant to the written de-
scription inquiry, because it does not point to any
disclosure in the specification to which the testimony could
relate.
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES        21



inherency. The Generics respond that Nuvo is wrong be-
cause that only satisfies the enablement requirement,
which is separate and distinct from the written description
requirement. As for inherency, the Generics note that the
district court rejected that ground for written description
support, and assert that Nuvo has not made out a case for
inherent disclosure.
                            1.
    Teaching how to make and use an invention does not
necessarily satisfy the written description requirement.
We have recognized that the enablement requirement,
which requires the specification to teach those skilled in
the art how to make and use the claimed invention without
undue experimentation, is separate and distinct from the
written description requirement. Ariad, 598 F.3d at 1343–
51. And the fact that an invention may be enabled does not
mean it is adequately described, and vice versa. Univ. of
Rochester, 358 F.3d at 921–22. That is because “[t]he pur-
pose of the written description requirement is broader than
to merely explain how to ‘make and use’ [the invention].”
Id. at 920. The focus of the written description require-
ment is instead on whether the specification notifies the
public about the boundaries and scope of the claimed in-
vention and shows that the inventor possessed all the as-
pects of the claimed invention. Id. at 926.
    Nuvo cites our decision in Alcon Research Ltd. v. Barr
Laboratories, Inc., 745 F.3d 1180 (Fed. Cir. 2014), to sup-
port its position that it is enough that the patents teach
making and using the claimed combination drug formula-
tion. The Generics argue that case is distinguishable. We
agree that Alcon does not save the claims of the ’907 and
’285 patents.
    In Alcon, patent claims were directed to a method for
enhancing the chemical stability of an aqueous solution
containing a therapeutically effective amount of a known
drug. 745 F.3d at 1184. We held that the claims were
22      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




adequately described because the disclosure in the specifi-
cation demonstrated that the inventor possessed and actu-
ally invented the claimed stability enhancing features of
the method. Id. at 1191. We noted that the patent refer-
enced the unexpected nature of the discovery, gave exem-
plary formulations, and disclosed data showing stability
testing using the claimed invention. Id.
    The factual circumstances in Alcon are markedly dif-
ferent than the facts presented here. Unlike the specifica-
tion of the patent at issue in Alcon, the specification of the
’907 and ’285 patents does not provide any data showing
that uncoated PPI is effective in raising the gastric pH of a
patient to at least 3.5. Even though we said in Alcon that
“written description is about whether the skilled reader of
the patent disclosure can recognize that what was claimed
corresponds to what was described” and “is not about
whether the patentee has proven to the skilled reader that
the invention works, or how to make it work,” we found
that the written description requirement was satisfied at
least in part by accelerated stability testing data showing
the claimed effect. Id. Under those circumstances, it was
not necessary for the patentee to demonstrate or otherwise
“prove” beyond the data disclosed in the specification that
the invention works. Here, there is no similar hook or dis-
closure in the specification that an ordinarily skilled arti-
san can rely on to understand that the inventor possessed
effective uncoated PPI.
                              2.
     Our case law has recognized that, under a narrow set
of circumstances, the written description requirement may
be satisfied without an explicit disclosure if the claimed
features are necessarily inherent in what is expressly de-
scribed. See, e.g., Allergan, 796 F.3d at 1309 (“A claim that
recites a property that is necessarily inherent in a formu-
lation that is adequately described is not invalid as lacking
written description merely because the property itself is
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES             23



not explicitly described.”); Yeda Research & Dev. Co. v. Ab-
bott GmbH & Co. KG, 837 F.3d 1341, 1345 (Fed. Cir. 2016)
(“Under the doctrine of inherent disclosure, when a speci-
fication describes an invention that has certain undisclosed
yet inherent properties, that specification serves as ade-
quate written description to support a subsequent patent
application that explicitly recites the invention’s inherent
properties.”); cf. Manual of Patent Examining Procedure
§ 2163 (9th ed. Rev. 3, Jan. 2018) (recognizing that inher-
ency may satisfy the written description requirement).
    Nuvo cites our decision in Allergan to support its posi-
tion that the claimed efficacy of uncoated PPI is necessarily
inherent in the specification’s explicit disclosure of meth-
ods for making and using drug formulations containing un-
coated PPI. The Generics contend that, like Alcon,
Allergan is also factually distinguishable. We agree.
     In Allergan, the patentee claimed a drug combination
effective for reducing intraocular pressure that included
0.01% bimatoprost and 200 ppm benzalkonium chloride
(“BAK”). 796 F.3d at 1300. But the prior art taught away
from the claimed combination of ingredients and the spec-
ification did not explicitly describe its clinical efficacy. Id.
at 1298, 1305–07, 1309. While we upheld the nonobvious-
ness of the claimed invention given the unexpected results
of and teaching away from increasing the amount of BAK
to decrease the amount of intraocular pressure, we also
held that the claims were supported by adequate written
description. Id. at 1305, 1309. We reasoned that the par-
ties did not dispute that “the inherent properties of a for-
mulation comprising 0.01% bimatoprost and 200 ppm BAK
produce the claimed clinical profile.” Id. at 1309. It was
enough that the specification described the formulation, its
components, and how to make and use it. Id. at 1308–09.
Moreover, there were experimental results for similar drug
formulations demonstrating a trend in their clinical effec-
tiveness, even if the data were not specifically related to
the exact formulation claimed. Id. at 1299–300.
24      NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES




    Here, unlike in Allergan, whether uncoated PPI is in-
herently effective in raising the gastric pH to at least 3.5 is
disputed. And there is no written disclosure that in any
way relates to the efficacy of immediately released PPI.
Neither party has identified any evidence in the record that
uncoated PPI necessarily is effective in a certain amount,
consistent with the specification, to raise the gastric pH to
3.5 or higher. Nor can we find any evidence in the record
demonstrating the inherency of the claimed feature. That
failure of proof thus dooms Nuvo’s inherency argument.
                              D
    Written description analyses are highly fact specific.
See Amgen Inc. v. Sanofi, 872 F.3d 1367, 1377 (Fed. Cir.
2017) (“[E]ach case involving the issue of written descrip-
tion must be decided on its own facts.” (alterations and in-
ternal quotation marks omitted) (quoting Noelle v.
Lederman, 355 F.3d 1343, 1349 (Fed. Cir. 2004))); Vas–
Cath Inc. v. Mahurkar, 935 F.2d 1555, 1562 (Fed. Cir.
1991) (“The CCPA’s ‘written description’ cases often
stressed the fact-specificity of the issue.”). Based on the
specific facts of certain cases, it is unnecessary to prove
that a claimed pharmaceutical compound actually achieves
a certain result. But when the inventor expressly claims
that result, our case law provides that that result must be
supported by adequate disclosure in the specification. In
this case, the inventor chose to claim the therapeutic effec-
tiveness of uncoated PPI, but he did not adequately de-
scribe the efficacy of uncoated PPI so as to demonstrate to
ordinarily skilled artisans that he possessed and actually
invented what he claimed. And the evidence demonstrates
that a person of ordinary skill in the art reading the speci-
fication would not have otherwise recognized, based on the
disclosure of a formulation containing uncoated PPI, that
it would be efficacious because he or she would not have
expected uncoated PPI to raise gastric pH. Under those
facts, the patent claims are invalid for lack of adequate
written description pursuant to § 112, ¶ 1.
NUVO PHARMACEUTICALS v. DR. REDDY’S LABORATORIES          25



                             II
    Because we hold that the ’907 and ’285 patents are in-
valid for lack of an adequate written description given that
the shared specification does not adequately describe the
claimed effectiveness of uncoated PPI, we do not need to
address the Generics’ alternative argument that the pa-
tents are also invalid under § 112, ¶ 1 for failing to ade-
quately describe uncoated, immediate release naproxen.
Similarly, because we conclude that the asserted claims are
invalid, Nuvo’s cross-appeal challenging the district court’s
grant of summary judgment of noninfringement with re-
spect to Dr. Reddy’s second ANDA product and the ’907 pa-
tent is moot.
                       CONCLUSION
    For the reasons stated above, we reverse the district
court’s determination that the asserted claims of the ’907
and ’285 patents are not invalid for lack of an adequate
written description. Those claims are invalid. We dismiss
as moot Nuvo’s cross-appeal challenging the district court’s
grant of summary judgment of noninfringement to Dr.
Reddy’s with respect to its second ANDA product and the
now-invalidated ’907 patent claims.
  REVERSED AS TO 17-2473, 17-2481, 17-2484, 17-
 2486; DISMISSED AS TO 17-2489, 17-2491, 17-2492,
                   17-2493.
                           COSTS
    No costs.
