  United States Court of Appeals
      for the Federal Circuit
                 ______________________

              ALCON RESEARCH LTD.,
                 Plaintiff-Appellant,

                            v.

            BARR LABORATORIES, INC.,
              Defendant-Cross-Appellant.
               ______________________

                    2012-1340, -1341
                 ______________________

    Appeals from the United States District Court for the
District of Delaware in No. 09-CV-0318, Judge Legrome
D. Davis.
                 ______________________

                Decided: March 18, 2014
                ______________________

    ADAM L. PERLMAN, Williams & Connolly LLP, of
Washington, DC, argued for plaintiff-appellant. With him
on the brief were GLENN J. PFADENHAUER, KEVIN HARDY,
and DAVID M. KRINSKY. Of counsel was KANNON K.
SHANMUGAM.

    WILLIAM P. FERRANTI, Winston & Strawn LLP, of Chi-
cago, Illinois, argued for defendant-cross appellant. With
him on the brief was GEORGE C. LOMBARDI. Of counsel on
the brief was BRADLEY C. GRAVELINE, Sheppard Mullin
Richter & Hampton, LLP, of Chicago, Illinois.
                    ______________________
2            ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.




    Before NEWMAN, LOURIE, and BRYSON, Circuit Judges.
LOURIE, Circuit Judge.
     Alcon Research Ltd. (“Alcon”) appeals from the final
judgments of the United States District Court for the
District of Delaware finding that Barr Laboratories, Inc.
(“Barr”) does not infringe claim 12 of Alcon’s U.S. Patent
5,631,287 (the “’287 patent”) and claim 19 of Alcon’s U.S.
Patent 6,011,062 (the “’062 patent”) and holding those
claims invalid for lack of enablement and lack of an
adequate written description under 35 U.S.C. § 112, ¶ 1. 1
Alcon Research Ltd. v. Barr Labs. Inc., 837 F. Supp. 2d
364 (D. Del. 2011). Barr cross-appeals from the district
court’s denial of Barr’s post-judgment motion pursuant to
Federal Rule of Civil Procedure 59(e) to amend the dis-
trict court’s judgment and enter judgment as a matter of
law (“JMOL”) of noninfringement as to Alcon’s U.S.
Patents 5,510,383 (the “’383 patent”) and 5,889,052 (the
“’052 patent”). Alcon Research Ltd. v. Barr Labs. Inc., No.
09-0318, 2012 WL 928189 (D. Del. Mar. 16, 2012).
    We conclude that the district court was not clearly er-
roneous in finding that Barr’s product would not infringe
the asserted claims of the ’287 and ’062 patents and that
the court did not abuse its discretion in denying Barr’s
motion to amend for JMOL of noninfringement of the ’383
and ’052 patents. However, we conclude that the district



     1   Paragraph 1 of 35 U.S.C. § 112 was replaced with
newly designated § 112(a) by § 4(c) of the Leahy-Smith
America Invents Act (“AIA”), Pub. L. No. 112-29, and AIA
§ 4(e) makes those changes applicable “to any patent
application that is filed on or after” September 16, 2012.
Because the applications resulting in the patents at issue
in this case were filed before that date, we will refer to the
pre-AIA version of § 112.
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.            3



court’s invalidity determinations as to the asserted claims
of the ’287 and ’062 patents were not in accordance with
law. Accordingly, we affirm in part and reverse in part.
                       BACKGROUND
    Alcon owns the ’287 and ’062 patents, which are di-
rected to methods for enhancing the stability of prosta-
glandin compositions, including Alcon’s glaucoma and
ocular hypertension drug Travatan Z®, which contains
travoprost, the synthetic prostaglandin fluprostenol
isopropyl ester. Claim 12 of the ’287 patent depends from
claim 1 of that patent and reads as follows:
    1. A method of enhancing the chemical stability
    of an aqueous composition comprising a therapeu-
    tically-effective amount of a prostaglandin, where-
    in the method comprises adding a chemically-
    stabilizing amount of a polyethoxylated castor oil
    [(“PECO”)] to the composition.
    12. The method of claim 1 wherein the composi-
    tion is a topically administrable ophthalmic com-
    position.
’287 patent col. 8 ll. 57–61, col. 10 ll. 53–54. The ’062
patent is a continuation in part of the ’287 patent. ’062
patent col. 1 ll. 1–10. Claim 19 of the ’062 patent, which
depends from claim 12 of that patent, is identical to claim
12 of the ’287 patent except that it limits the requisite
PECO to one “selected from the group of PEG-5 to PEG-
200 hydrogenated castor oils.” Id. col. 11 l. 65–col. 12 l. 3,
col. 14 ll. 15–16.
    Barr submitted Abbreviated New Drug Application
(“ANDA”) 91-411 to the U.S. Food and Drug Administra-
tion (the “FDA”), seeking approval to manufacture, use,
and sell an ophthalmic travoprost solution as a generic
version of Travatan Z®. Barr’s ANDA filing was second to
that of Par Pharmaceuticals, Inc. Alcon, 837 F. Supp. 2d
at 368. Although the ’287 and ’062 patents are not listed
4           ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



as referenced to Travatan Z® in the Approved Drug Prod-
ucts with Therapeutic Equivalence Evaluations publica-
tion (commonly known as the “Orange Book”) maintained
by the FDA, Alcon initiated suit, asserting that Barr’s
ANDA submission constituted an act of infringement of
claim 12 of the ’287 patent, claim 19 of the ’062 patent,
and claims from four other patents, including its Orange
Book-listed ’383 and ’052 patents. However, Alcon did not
assert its ’383 and ’052 patents at trial and neither party
adduced any evidence that specifically related to those
patents. Barr stipulated that its generic product in-
fringed the remaining two patents that Alcon had assert-
ed, viz., U.S. Patents 6,503,497 and 6,849,253, and that
those patents were not invalid. Id. 2
    Following a Markman hearing, the district court con-
strued the claimed phrase “enhancing the chemical stabil-
ity” to mean “to increase or increasing the ability of the
prostaglandin to resist chemical change (as distinguished
from merely increasing the physical stability of the pros-
taglandin or composition),” i.e., “reducing or decreasing
[travoprost] degradation.” Id. at 369; see also Alcon
Research Ltd. v. Barr Labs. Inc., No. 09-0318, 2011 WL
3901878, at *15–16 (D. Del. Sept. 6, 2011). The court
distinguished physical stability as referring to physical
phenomena such as absorption, adsorption, and precipita-
tion. Id.
    The court also construed the claim term “prostaglan-
din” to correspond to the disclosure in the written descrip-
tion of the patents regarding the prostaglandins that may
be used with the invention. Alcon, 2011 WL 3901878, at
*13–14. The court thus determined the term “prostaglan-


    2   Neither party raises or challenges the propriety of
asserting patents that were not listed in the Orange Book
against a generic manufacturer based on the filing of an
ANDA, and we accordingly do not reach that issue.
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         5



din” to mean “the natural compounds PGE1, PGE2, PGE3,
PGF1α, PGF2α, PGF3α, PGD2, and PGI2 (prostacyclin), as
well as analogues and derivatives of such natural com-
pounds (including the pharmaceutically acceptable esters
and salts of such natural compounds and their analogues
and derivatives), which have similar biological activities
of either greater or lesser potencies.”      Id. at *15.
Travoprost is a type PGF2α prostaglandin analog.
    After a bench trial, the court found that Barr’s ANDA
product did not infringe either claim 12 of the ’287 patent
or claim 19 of the ’062 patent because Alcon failed to
prove by a preponderance of the evidence that Barr manu-
factured its generic Travatan Z® product by a method that
comprised adding a chemically-stabilizing amount of
PECO to its composition. Alcon, 837 F. Supp. 2d at 369.
The court noted that Alcon did not test Barr’s product and
determined that Alcon’s only evidence was an accelerated
stability study conducted by Alcon during its development
work that compared several travoprost compositions with
different amounts of PECO. Id. at 373–80.
    The court found that Table 7 of Alcon’s development
study recorded data showing that some amount of
travoprost was lost over an eight week test period, but the
parties disputed the reason for that loss, viz., physical
instability versus chemical instability. Id. at 374–80.
The court nevertheless found that the results “could be
attributed to a number of factors other than PECO en-
hancing the chemical stability of the Travoprost, e.g.,
experimental error or uncertainty, adsorption, precipita-
tion, or other physical loss” and that, in any event, “the
tested formulations differ[ed] significantly from Barr’s
ANDA product.” Id. at 376. Accordingly, in finding
noninfringement, the court ultimately concluded that
because “variables such as pH, buffer, buffer concentra-
tion, preservatives, chelating agents, and other excipients
can affect the chemical stability of prostaglandins in
opthalmic formulations,” as Alcon conceded, “the composi-
6           ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



tional differences between [Alcon’s] Solubility Study
formulations and Barr’s ANDA product preclude[d] . . .
relying on the Solubility Study data to draw any reliable
inferences with respect to the stability of Barr’s ANDA
product.” Id. at 376–77.
    The court also held claim 12 of the ’287 patent and
claim 19 of the ’062 patent invalid under 35 U.S.C. § 112,
¶ 1, for lack of enablement and lack of an adequate writ-
ten description. Id. at 370, 380–84. The court concluded
that Barr proved by clear and convincing evidence that
one skilled in the art could neither carry out the full scope
of the asserted claims without undue experimentation nor
would have recognized that the inventors were in posses-
sion of the claimed invention at the time the patent
applications were filed because: (i) the claims were too
broad; (ii) the patent disclosure was too limited; and (iii)
the art of chemically stabilizing prostaglandins was too
unpredictable. Id. However, the court rejected Barr’s
asserted defenses that Alcon’s claims were invalid for
anticipation, obviousness, and indefiniteness. Id. at 370–
71, 384–92.
    Barr then moved for JMOL of noninfringement of Al-
con’s ’383 and ’052 patents, which the court denied,
“declin[ing] to make any findings or draw any conclusions
about the infringement or validity of [those] patents”
because “neither party presented any evidence” on them
and thus they “were not actually litigated and adjudicat-
ed” or fairly placed at issue during trial. Id. at 371, 392.
Barr subsequently filed a post-judgment motion pursuant
to Federal Rule of Civil Procedure 59(e) to amend the
district court’s judgment and to enter JMOL of nonin-
fringement of those two patents on the ground that the
court’s resolution of the matter in the first instance con-
stituted a clear error of law that required correction in
order “to prevent manifest injustice.” Alcon, 2012 WL
928189, at *8.
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         7



    The court again denied Barr’s motion. Id. at *7–12.
The court reasoned that, because Barr had never filed a
counterclaim, Barr had no basis to assert that it was
entitled to a declaratory judgment of noninfringement
given that Alcon lacked fair notice of the risk of such an
adverse determination. Id. at *7, *11. The court held
that “the parties’ joint pretrial submissions reflected the
parties’ understanding that the unasserted claims were
no longer a part of the case.” Id. at *10. Accordingly, the
court concluded that the pleadings should “be conformed
to the judgment, not vice versa.” Id. at *9 (quoting Tol-O-
Matic, Inc. v. Proma Produkt-Und Mktg. G.m.b.H., 945
F.2d 1546, 1554–55 (Fed. Cir. 1991)).
    Alcon timely appealed and Barr timely cross-
appealed. We have jurisdiction pursuant to 28 U.S.C.
§ 1295(a)(1).
                        DISCUSSION
                              I
    Infringement is a question of fact that we review for
clear error. Amgen Inc. v. Hoechst Marion Roussel, Inc.,
314 F.3d 1313, 1339 (Fed. Cir. 2003). A factual finding is
clearly erroneous when, despite some supporting evi-
dence, we are left with a definite and firm conviction that
the district court was in error. Alza Corp. v. Mylan Labs.,
Inc., 464 F.3d 1286, 1289 (Fed. Cir. 2006).
    Alcon argues that the district court erred in finding
that Barr’s ANDA product did not infringe the asserted
claims of Alcon’s ’287 and ’062 patents because its testing
of travoprost formulations containing the same PECO in
the same concentration as Barr’s proposed generic prod-
uct demonstrated that the PECO added to Barr’s composi-
tion enhances the stability of the prostaglandin. Alcon
contends that the district court’s findings are undermined
by its purportedly improper credibility determinations
regarding Alcon’s experts and its consequent rejection of
8           ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



their testimony. Barr responds that it does not infringe
because Alcon presented no evidence directly relating to
whether Barr’s ANDA product infringed the ’287 and ’062
patents and no evidence directly relating to whether
PECO enhances the chemical stability of any prostaglan-
din.
    We agree with Barr that Alcon failed to present evi-
dence of infringement. Unlike a classic patent infringe-
ment case in which infringement exists if at least one
claim of an asserted patent reads on a product or process
that the accused infringer has introduced into the U.S.
marketplace, an infringement inquiry provoked by an
ANDA filing under the Hatch-Waxman system pursuant
to 35 U.S.C. § 271(e)(2)(A) is focused on a comparison of
the asserted patent against “the product that is likely to
be sold following ANDA approval.” Abbott Labs. v. Tor-
Pharm, Inc., 300 F.3d 1367, 1373 (Fed. Cir. 2002). That
determination is based on consideration of all of the
relevant evidence and, “[b]ecause drug manufacturers are
bound by strict statutory provisions to sell only those
products that comport with the ANDA’s description of the
drug, an ANDA specification defining a proposed generic
drug in a manner that directly addresses the issue of
infringement will control the infringement inquiry.” Id.;
see also Sunovion Pharm., Inc. v. Teva Pharm. USA, Inc.,
731 F.3d 1271, 1279–80 (Fed. Cir. 2013); Bayer AG v.
Elan Pharm. Research Corp., 212 F.3d 1241, 1248–50
(Fed. Cir. 2000); Glaxo, Inc. v. Novopharm, Ltd., 110 F.3d
1562, 1569–70 (Fed. Cir. 1997).
    In its attempt to prove that the addition of PECO in
Barr’s proposed generic product would chemically stabi-
lize the prostaglandin travoprost and thus infringe the
asserted claims of the ’287 and ’062 patents, Alcon relied
solely on a theory that the data reported in Table 7 of a
stability study that Alcon conducted during its develop-
ment work could be extrapolated to infer that the addition
of PECO would chemically stabilize travoprost in Barr’s
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.        9



ANDA composition. The data in Table 7 of Alcon’s report,
which was styled as a “Soaking Study to Evaluate the
Compatibility of Travoprost with Polypropylene Packag-
ing Materials,” were generated by subjecting travoprost
compositions to elevated temperatures and then analyz-
ing them at regular intervals to measure the amount of
travoprost remaining in the composition. J.A. 6984. At
trial, both parties agreed that the data showed that
travoprost was lost over time—that is, less travoprost was
present in the tested compositions at the end of eight
weeks than had been present when the test began—and
that more travoprost remained in the compositions with
0.5% PECO at the end of eight weeks than in the composi-
tion that did not contain any PECO. J.A. 5619–25, 6066.
    Critically, however, the district court found, and the
parties do not dispute on appeal, that the composition of
the generic product proposed in Barr’s ANDA is signifi-
cantly different from the compositions tested in Alcon’s
study. Alcon, 837 F. Supp. 2d at 376; J.A. 6984, 6991.
The test formulations used by Alcon to compile the data in
Table 7 were maintained at pH 6.0–6.1 and contained,
inter alia, 0.005% weight by volume of travoprost, varying
concentrations of PECO, the antimicrobial preservative
benzalkonium chloride, and a buffer solution comprising
tromethamine, boric acid, and mannitol. Id. In contrast,
the generic product proposed in Barr’s ANDA is main-
tained at a different pH, is composed of 0.004% weight by
volume of travoprost and a buffered preservative system
comprising propylene glycol, sorbitol, and zinc chloride,
but does not contain benzalkonium chloride or a tro-
methamine/boric acid/mannitol buffer solution. Id. Alcon
itself admitted that variation in parameters including pH,
preservatives, and buffers can have a substantial impact
on the chemical stability of a prostaglandin in an oph-
thalmic formulation. Id. at 376–77; Appellant Br. 39; J.A.
5539–40, 5985. The data in Table 7 therefore were not
10          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



evidence that Barr’s product, if and when approved, would
infringe the asserted claims.
    We thus conclude that the district court did not clear-
ly err in finding that the data in Alcon’s Table 7 had no
bearing on whether Barr’s proposed generic product
infringed Alcon’s patents. The formulations tested in
Alcon’s stability study were meaningfully different from
the product described in Barr’s ANDA and thus provided
no basis from which to draw any reliable inferences
regarding whether the PECO in Barr’s composition would
chemically stabilize the prostaglandin. See Lucent Tech.,
Inc. v. Gateway, Inc., 543 F.3d 710, 722–24 (Fed. Cir.
2008) (recognizing that overly speculative circumstantial
evidence will not suffice to prove infringement).
    We have considered Alcon’s remaining arguments re-
garding the district court’s infringement analysis and find
them unpersuasive. Accordingly, we affirm the district
court’s holding that Alcon failed to prove by a preponder-
ance of the evidence that the generic product described in
Barr’s ANDA infringes either claim 12 of Alcon’s ’287
patent or claim 19 of Alcon’s ’062 patent.
                             II
     Section 112 of the patent statute describes what must
be contained in a patent specification. Among other
requirements, it must contain “a written description of
the invention, and of the manner and process of making
and using it . . . [such] as to enable any person skilled in
the art to which it pertains, . . . to make and use the same
. . . .” 35 U.S.C. § 112, ¶ 1 (2006). Thus, this statutory
language mandates satisfaction of two separate and
independent requirements: an applicant must both de-
scribe the claimed invention adequately and enable its
production and use. Ariad Pharm., Inc. v. Eli Lilly & Co.,
598 F.3d 1336, 1344 (Fed. Cir. 2010) (en banc); Vas-Cath
Inc. v. Mahurkar, 935 F.2d 1555, 1562–63 (Fed. Cir.
1991).
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         11



    Furthermore, patents are presumed to be valid and
overcoming this presumption requires clear and convinc-
ing evidence. 35 U.S.C. § 282; Microsoft Corp. v. i4i Ltd.,
131 S. Ct. 2238, 2242 (2011); Ariad, 598 F.3d at 1354.
                             A
    Whether a claim satisfies the enablement require-
ment of 35 U.S.C. § 112 is a question of law that we
review without deference, although the determination
may be based on underlying factual findings, which we
review for clear error. Sitrick v. Dreamworks, LLC, 516
F.3d 993, 999 (Fed. Cir. 2008).
    Alcon argues that the district court erred in holding
the asserted claims of the ’287 and ’062 patents invalid for
lack of enablement because it only weighed the breadth of
the claims against the detail of the patent disclosures.
Alcon contends that Barr presented no evidence that any
experimentation would be required for a person of ordi-
nary skill in the art to practice the invention as claimed.
    Barr responds that the patents provide very little
guidance to one skilled in the art in the form of only three
working examples and do not disclose any data for chemi-
cal stability. Barr contends that the reported data relate
only to physical stability, not prostaglandin degradation,
and that the patents do not disclose how PECOs work to
chemically stabilize prostaglandins. Barr further asserts
that the technology at issue is highly unpredictable,
particularly with regard to choice of pH, buffer, buffer
concentration, preservatives, chelating agents, and other
excipients.
     We agree with Alcon that the district court erred in
its enablement analysis. To prove that a claim is invalid
for lack of enablement, a challenger must show by clear
and convincing evidence that a person of ordinary skill in
the art would not be able to practice the claimed invention
without “undue experimentation.” In re Wands, 858 F.2d
12          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



731, 736–37 (Fed. Cir. 1988); see also Johns Hopkins
Univ. v. CellPro, Inc., 152 F.3d 1342, 1360 (Fed. Cir.
1998) (“[I]t is imperative when attempting to prove lack of
enablement to show that one of ordinary skill in the art
would be unable to [practice] the claimed invention with-
out undue experimentation.”) (emphasis omitted). After
the challenger has put forward evidence that some exper-
imentation is needed to practice the patented claim, the
factors set forth in Wands then provide the factual con-
siderations that a court may consider when determining
whether the amount of that experimentation is either
“undue” or sufficiently routine such that an ordinarily
skilled artisan would reasonably be expected to carry it
out. Wands, 858 F.2d at 737.
    The district court erred here because its enablement
analysis did not address that determinative question:
Barr failed to make the threshold showing that any
experimentation is necessary to practice the claimed
methods, i.e., to use PECO to enhance the stability of a
prostaglandin given the disclosures of Alcon’s ’287 and
’062 patents. Instead, the district court’s holding rested
on its finding that the full scope of the claims was not
enabled after applying the Wands factors as if they were a
generalized test for deciding whether a patent disclosure
is sufficiently detailed to support a broad claim. Alcon,
837 F. Supp. 2d at 370, 380–83.
    The claimed methods comprise only a single step—
adding a chemically-stabilizing amount of PECO to the
prostaglandin composition—that Barr’s own expert testi-
fied was “routine.” J.A. 6069. The claims as a whole
merely require that the addition of PECO to the composi-
tion provide some increase in chemical stability, but do
not require a particular level of stability or a particular
magnitude of increase. Moreover, the patents disclose
exemplary compositions within the scope of the claims,
detail how those example compositions are prepared from
commercially-available ingredients, and provide step-by-
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.            13



step procedures for adding PECO to a prostaglandin
composition in a way that embodies the claimed inven-
tion. ’287 patent col. 7 l. 26–col. 8 l. 46; ’062 patent col. 7
l. 63–col. 9 l. 42. The patents also identify the various
prostaglandins and PECOs that can be used and a range
of suitable concentrations for both components, including
narrow preferred embodiments. ’287 patent col. 2 l. 7–col.
6 l. 37; ’062 patent col. 2 l. 16–col. 7 l. 1.
    In light of those disclosures, the district court’s non-
enablement ruling was premised on testimony that many
“variables” including the number of prostaglandins and
the range of PECOs encompassed by the claims, as well as
“[v]arious parameters including pH, buffer, buffer concen-
tration, preservatives, chelating agents, and other excipi-
ents may affect the chemical stability of prostaglandins in
ophthalmic formulations.” Alcon, 837 F. Supp. 2d at 382–
83 (emphasis added). Indeed, Barr’s expert observed that
“when ‘you have a lot of variables on top of one another,
the experimentation gets out of control quickly.’” Id. at
383 (citing J.A. 6009). But such an unsubstantiated
conclusory statement is not sufficient. Cephalon, Inc. v.
Watson Pharm., Inc., 707 F.3d 1330, 1339 (Fed. Cir.
2013). Barr adduced no evidence at trial that changing
any of the “variables” or “[v]arious parameters” identified
by the district court would render Alcon’s claimed inven-
tion inoperable, nor was there any evidence that experi-
menting with those variables was required for an
ordinarily skilled artisan to be capable of increasing the
chemical stability of a prostaglandin by adding PECO.
Adjusting variables may be relevant to optimizing the
stability of a given prostaglandin composition, but Barr
proffered no evidence that any experimentation, let alone
undue experimentation, with those variables would be
necessary in order to practice the claimed invention.
Without that evidence, there is no foundation for the
district court’s nonenablement ruling.
14          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



    Furthermore, a patent does not need to guarantee
that the invention works for a claim to be enabled. It is
well settled that an invention may be patented before it is
actually reduced to practice. Pfaff v. Wells Elecs., Inc.,
525 U.S. 55, 61 (1998). Similarly, a patentee is not re-
quired to provide actual working examples; we have
rejected enablement challenges based on the theory that
there can be no guarantee that prophetic examples actual-
ly work, as “[t]he burden is on one challenging validity to
show by clear and convincing evidence that the prophetic
examples together with other parts of the specification are
not enabling.” Atlas Powder Co. v. E.I. du Pont de
Nemours & Co., 750 F.2d 1569, 1577 (Fed. Cir. 1984).
Nor is it “a requirement of patentability that an inventor
correctly set forth, or even know, how or why the inven-
tion works.” Newman v. Quigg, 877 F.2d 1575, 1581–82
(Fed. Cir. 1989) (citing Diamond Rubber Co. v. Consol.
Rubber Tire Co., 220 U.S. 428, 435–36 (1911)). Thus, it is
likewise irrelevant here, as a legal matter, whether the
’287 and ’062 patents contain data proving that PECOs
enhance the chemical stability of prostaglandins.
    Accordingly, because Barr did not show that any
claimed embodiments would be inoperable and that a
person of ordinary skill in the art would have been unable
to practice the asserted claims without resorting to any
experimentation, let alone undue experimentation, we
conclude that the district court erred as a matter of law in
holding that Barr proved its invalidity case based on
nonenablement by clear and convincing evidence. Barr
had the burden of proof to show that Alcon’s patents
lacked enabling disclosures, but failed to carry that bur-
den. We therefore reverse the district court’s judgment
that claim 12 of the ’287 patent and claim 19 of the ’062
patent are invalid for lack of enablement.
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         15



                             B
     Whether a claim satisfies the written description re-
quirement is a question of fact that, on appeal from a
bench trial, we review for clear error. Ariad, 598 F.3d at
1351. However, the district court’s interpretation of
precedent regarding the written description requirement
is reviewed without deference. Amgen, 314 F.3d at 1338.
    Alcon argues that the district court erred in holding
the asserted claims of the ’287 and ’062 patents invalid for
lack of an adequate written description because the
patent specifications sufficiently describe the invention
and a variety of the embodiments that the inventor envis-
aged. Alcon contends that there was no evidence that a
person of ordinary skill in the art would not have recog-
nized or understood that the inventor possessed the
claimed invention.
    Barr responds that the claims “flunk the written de-
scription requirement” because they encompass “a method
for enhancing the chemical stability of innumerable
prostaglandins by adding to them PECO in an endless
number of combinations and concentrations” and there-
fore are not precise and “overreach” the scope of the
patent disclosures. Appellant Br. 49–50. Barr contends
that the specifications only disclose physical data from
one compound to support the proposition that PECO
enhances the chemical stability of all prostaglandins, but
that they do not disclose any data on chemical stability,
prostaglandin degradation products, or prostaglandin
degradation pathways.
    We agree with Alcon that the specifications provide
an adequate written description of the claimed invention.
“[T]he hallmark of written description is disclosure.”
Ariad, 598 F.3d at 1351. The standard for satisfying the
written description requirement is whether the disclosure
“allow[s] one skilled in the art to visualize or recognize
the identity of the subject matter purportedly described.”
16          ALCON RESEARCH LTD.    v. BARR LABORATORIES, INC.



Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956, 968
(Fed. Cir. 2002). There is no requirement that the disclo-
sure contain “either examples or an actual reduction to
practice”; rather, the critical inquiry is whether the pa-
tentee has provided a description that “in a definite way
identifies the claimed invention” in sufficient detail that a
person of ordinary skill would understand that the inven-
tor was in possession of it at the time of filing. Ariad, 598
F.3d at 1350, 1352; Koito Mfg. Co. v. Turn-Key-Tech.,
LLC, 381 F.3d 1142, 1154 (Fed. Cir. 2004). That assess-
ment “requires an objective inquiry into the four corners
of the specification.” Ariad, 598 F.3d at 1351.
     The ’287 patent details the claimed invention and
provides a step-by-step description of how a person of
ordinary skill in the art may use it. It discloses the
“unexpected[] discover[y] that the use of . . . polyethox-
ylated castor oils in [pharmaceutical] compositions,”
especially those “topically applied to the eye,” “enhances
the chemical stability of prostaglandins.” ’287 patent col.
1 ll. 46–51; col. 6 l. 16–col. 7 l. 25. It provides exemplary
formulations that embody the claimed invention, reciting
concentrations of every ingredient. Id. col. 7 ll. 26–46. It
also discloses data generated by the inventor from accel-
erated stability testing showing the effect of PECO and
prostaglandin concentration on stability and comparing
the effect of PECO to that of a more commonly used
surfactant, polysorbate 80. Id. figs. 2 & 3, col. 1 ll. 59–62,
col. 8 ll. 32–39. The patent also describes various classes
of prostaglandins to which the invention was understood
to relate, which are covered by the term “prostaglandin”
under the district court’s construction of that term, as
well as preferred concentrations and thirty-two specifical-
ly preferred examples of those prostaglandins. Id. col. 2 l.
23–col. 6 l. 15. It describes various types of PECOs that
may be used in the invention, again with preferred types
and concentrations. Id. col. 2 ll. 7–21. And the patent
describes the various formulation parameters, including
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         17



osmolality and pH, that may be selected when practicing
the invention. Id. col. 7 ll. 8–14.
     The ’062 patent, which is a continuation in part of the
’287 patent, contains largely the same written description
as the ’287 patent but is focused on the use of hydrogen-
ated PECOs. The ’062 patent thus includes additional
disclosures regarding the preferred types of hydrogenated
PECOs that may be used with the claimed invention, two
additional specifically preferred prostaglandins, and three
additional exemplary formulations. Id. col. 2 ll. 16–33,
col. 6 ll. 9–21, col. 9 ll. 20–42.
    In summary, the ’287 and ’062 patent disclosures
demonstrate that the inventors possessed the claimed
invention: they conceived of and described their invention
at the time the respective original patent applications
were filed, including the idea that adding PECO would
enhance the chemical stability of prostaglandins across a
range of various formulation parameters as cited by the
district court. See Koito, 381 F.3d at 1154–55. That is all
that the written description requirement demands. Id.
    Despite these disclosures, the district court concluded
that the asserted claims were invalid for lack of an ade-
quate written description “for essentially the same rea-
sons that they fail the enablement requirement . . . .”
Alcon, 837 F. Supp. 2d at 384. But written description is
about whether the skilled reader of the patent disclosure
can recognize that what was claimed corresponds to what
was described; it is not about whether the patentee has
proven to the skilled reader that the invention works, or
how to make it work, which is an enablement issue. See
Ariad, 598 F.3d at 1352. Barr’s argument regarding the
difference between physical and chemical stability, even if
correct, is thus not relevant to the inquiry. Critically,
Barr adduced no evidence, let alone clear and convincing
evidence, that was probative of whether an ordinarily
skilled artisan would not have understood from the dis-
18          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



closures of Alcon’s ’287 and ’062 patents that the patent-
ees invented, or possessed, the methods of the asserted
claims. Without that evidence, there was no basis on
which to find a lack of adequate written description.
    Accordingly, we conclude that the district court erred
in failing to apply the proper test for determining whether
the patents recited an adequate written description and
Barr again did not meet its burden of proving invalidity
by clear and convincing evidence. We therefore reverse
the district court’s judgment that claim 12 of the ’287
patent and claim 19 of the ’062 patent are invalid for lack
of an adequate written description.
                            III
    Barr argues that its cross-appeal is subject to de novo
review because it is an appeal from the denial of judgment
as a matter of law. Appellee Br. 51. However, unlike a
typical motion for judgment as a matter of law, the issues
presented in this case are whether Alcon’s infringement
claims regarding its ’383 and ’052 patents were actually
at issue during the trial below and whether the district
court erred in denying Barr’s Rule 59(e) post-judgment
motion to amend. Those issues are thus limited to proce-
dural matters not within our exclusive jurisdiction and we
therefore apply the law of the circuit in which the district
court sits, here the Third Circuit. See Ajinomoto Co., Inc.
v. Archer-Daniels-Midland Co., 228 F.3d 1338, 1350 (Fed.
Cir. 2000); Biodex Corp. v. Loredan Biomedical, Inc., 946
F.2d 850, 857–58 (Fed. Cir. 1991) (“[O]ur practice has
been to defer to regional circuit law when the precise
issue involves an interpretation of the Federal Rules of
Civil Procedure or the local rules of the district court.”).
    In the Third Circuit, “a trial judge has broad discre-
tion to determine which issues may be pursued at trial,”
Price v. Inland Oil Co., 646 F.2d 90, 94 (3d Cir. 1981), and
“[w]hen a district court rejects a motion to alter or amend
a judgment, [the Third Circuit’s] standard of review is
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.          19



whether the district court abused its discretion,” Donivan
v. Dallastown Borough, 835 F.2d 486, 487 (3d Cir. 1987).
Review is plenary, however, if the district court based its
decision on an error of law. Bushman v. Halm, 798 F.2d
651, 656 n.9 (3d Cir. 1986).
    Barr argues that it is entitled to an affirmative judg-
ment that Alcon’s ’383 and ’052 patents are not infringed
because Alcon neither put forward evidence of infringe-
ment nor formally obtained a dismissal of the claims
involving those patents from its complaint prior to trial.
Alcon responds that the district court correctly denied
Barr’s motion because Barr never filed a counterclaim
seeking a declaratory judgment of noninfringement,
which could have preserved its ability to seek an adjudi-
cation of the ’383 and ’052 patents after they were re-
moved from the case.
    We agree with Alcon that the district court correctly
denied Barr’s motion. Rule 59(e) is not a vehicle for
reopening judgments to present information that was long
possessed by the movant and that was directly relevant to
the litigation. Ajinomoto, 228 F.3d at 1350. The Third
Circuit has instructed that:
   A proper motion to alter or amend judgment must
   rely on one of three major grounds: (1) an inter-
   vening change in controlling law; (2) the availabil-
   ity of new evidence not available previously; or (3)
   the need to correct clear error of law or prevent
   manifest injustice.
N. River Ins. Co. v. CIGNA Reinsurance Co., 52 F.3d 1194,
1218 (3d Cir. 1995) (internal quotations omitted and
alterations included). Applying those grounds here, there
was no intervening change of law and the motion was not
supplemented with additional evidence.
    At bottom, Barr’s argument is that the district court’s
refusal to enter JMOL on Alcon’s ’383 and ’052 patents
20          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



was a clear error of law, but we conclude that the district
court correctly applied precedent. The court assessed
both what the parties expected to try given their state-
ments and conduct and what they actually litigated at
trial. Alcon, 2012 WL 928189, at *9–11. Alcon informed
Barr of its decision to drop its claims based on those
patents and Barr subsequently omitted them from the
pretrial order. Id. at *8; J.A. 2295, 11527–28. The pa-
tents were not “litigated, or fairly placed in issue, during
the trial.” Tol-O-Matic, 945 F.2d at 1554. The record on
appeal shows that neither party ever put forward any
arguments or evidence on the merits of infringement or
validity. A court should not render judgment with respect
to claims “reference[d] in the complaint” but not raised in
the pretrial statement or litigated at trial; “a reference in
the complaint is not sufficient to support a judgment.”
800 Adept, Inc. v. Murex Sec., Ltd., 539 F.3d 1354, 1367–
68 (Fed. Cir. 2008). The scope of any judgment should
conform to the issues that were actually litigated, as the
district court did here. See Fox Grp., Inc. v. Cree Inc., 700
F.3d 1300, 1308 (Fed. Cir. 2012).
     Moreover, we have not previously held that a formal
motion or stipulation was required to remove claims from
a case and we decline to do so here. On the contrary, we
recently decided that a patentee’s announcement that it
was no longer pursuing particular claims, coupled with its
ceasing to litigate them, was sufficient to remove those
claims from the case even without such formalities.
SanDisk Corp. v. Kingston Tech. Co., 695 F.3d 1348, 1353
(Fed. Cir. 2012). Consistent with our precedent, the
district court acknowledged that the claims regarding the
’383 and ’052 patents were no longer in the case as of the
time of the trial and did not abuse its discretion in essen-
tially deeming Alcon’s complaint as amended to remove
them. See id.
   Finally, unlike its codefendants, Barr neither filed a
counterclaim for declaratory judgment of noninfringement
ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.         21



nor sought leave to do so once Alcon announced that it
would not assert the ’383 and ’052 patents. Alcon, 2012
WL 928189, at *7–8; J.A. 177–92. Had Barr invoked that
right during the pendency of the action below, the district
court might have exercised its discretion differently. See
id. at *11. See generally 35 U.S.C. § 271(e)(5) and 21
U.S.C. § 355(j)(5)(C)(i)(II) (authorizing a “civil action”
under 28 U.S.C. § 2201 “for a declaratory judgment that
the patent is invalid or will not be infringed by the drug
for which the [ANDA] applicant seeks approval”); Dey
Pharma, LP v. Sunovion Pharm. Inc., 677 F.3d 1158 (Fed.
Cir. 2012) (upholding district court’s jurisdiction over
second ANDA filer’s action for declaratory judgment
within Hatch-Waxman framework). If an accused in-
fringer has filed a counterclaim, then the patentee has
notice that, even if it drops its infringement claims, the
issue of infringement remains to be litigated. On the
other hand, if the accused infringer does not file a coun-
terclaim, then it is up to the patentee to decide what
claims are to be litigated and decided at trial. Likewise,
“the district court has broad discretion in deciding wheth-
er to re-open a case, after the entry of judgment, to permit
another infringement trial of issues that could have been
resolved concurrently, with the benefit of the expertise
and effort of the first trial.” Ajinomoto, 228 F.3d at 1351.
We conclude that the court did not abuse its discretion
here.
     We have considered Barr’s remaining cross-appeal ar-
guments and find them unpersuasive. Accordingly, we
affirm the district court’s denial of Barr’s motion to
amend for JMOL of noninfringement.
                        CONCLUSION
    In view of the foregoing, we conclude that the district
court’s assessment that Barr’s ANDA products would not
infringe either claim 12 of Alcon’s ’287 patent or claim 19
of Alcon’s ’062 patent was correct and we therefore affirm
22          ALCON RESEARCH LTD.   v. BARR LABORATORIES, INC.



that judgment. We further conclude that those claims are
not invalid under § 112, ¶ 1 and accordingly we reverse
the district court’s contrary holding. Finally, because we
conclude that the district court did not abuse its discre-
tion in denying Barr’s Rule 59(e) motion to amend for
JMOL of noninfringement as to Alcon’s ’383 and ’052
patents, we affirm that decision.
     AFFIRMED IN PART and REVERSED IN PART
