  United States Court of Appeals
      for the Federal Circuit
              __________________________

                    POZEN INC.,
                   Plaintiff-Appellee,
                           v.
          PAR PHARMACEUTICAL, INC.,
               Defendant-Appellant,
                          AND

       DR. REDDY’S LABORATORIES, INC.,
              Defendant-Appellant,
                          AND

             ALPHAPHARM PTY LTD.,
                Defendant-Appellant.
              __________________________

                2011-1584, -1585, -1586
              __________________________

   Appeal from the United States District Court for the
Eastern District of Texas in Consolidated Case Nos. 08-
CV-0437, 09-CV-0003, and 09-CV-0182, Judge Leonard
Davis.
              __________________________

             Decided: September 28, 2012
              __________________________

   STEPHEN M. HASH, Vinson & Elkins LLP, of Austin,
Texas, argued for plaintiff-appellee. With him on the
POZEN INC   v. PAR PHARMA                                 2


brief were TRACEY B. DAVIES, WILLEM G. SCHUURMAN and
JENNIFER LIBRACH NALL; and STEPHANIE LOLLO DONAHUE
and REBECCA J. CANTOR, of New York, New York.

    RICHARD J. BERMAN, Arent Fox LLP, of Washington,
DC, argued for defendant-appellants Par Pharmaceutical,
Inc. and Alphapharm Pty., Ltd. Of counsel on the brief
was THOMAS J. PARKER, Alston & Bird, LLP, of New York,
New York. Of counsel for Par Pharmaceutical, Inc. were
TANIEL ERMANO ANDERSON, TIMOTHY BUCKNELL, AZIZ
BURGY, JANINE A. CARLAN, JOSHUA T. MORRIS and AMY E.
LIGLER SCHOENHARD. Of counsel for Alphapharm Pty.,
Ltd., was NATALIE C. CLAYTON, Alston & Bird, LLP, of
New York, New York.

    PAUL H. KOCHANSKI, Lerner, David, Littenberg,
Krumholz & Mentlik, LLP, of Westfield, New Jersey,
argued for defendant-appellant, Dr. Reddy’s Laboratories,
Inc. With him on the brief were MICHAEL H. TESCHNER
and ROY H. WEPNER.
               __________________________

   Before NEWMAN, CLEVENGER, and WALLACH, Circuit
                      Judges.
  Opinion for the court filed by Circuit Judge WALLACH.
    Dissenting-in-part opinion filed by Circuit Judge
                       CLEVENGER.
WALLACH, Circuit Judge.
                       INTRODUCTION
    Par Pharmaceutical, Inc. (“Par”), Alphapharm Pty
Ltd. (“Alphapharm”), and Dr. Reddy’s Laboratories, Inc.
(“DRL”) (collectively “Appellants”) appeal from the final
judgment of the United States District Court for the
Eastern District of Texas. Following a bench trial, the
3                                   POZEN INC   v. PAR PHARMA


district court determined that the asserted claims of U.S.
Patent No. 6,060,499 (filed Sept. 11, 1998) (the “’499
patent”), U.S. Patent No. 6,586,458 (filed Apr. 27, 2000)
(the “’458 patent”), and U.S. Patent No. 7,332,183 (filed
Dec. 22, 2003) (the “’183 patent”) (collectively “patents-in-
suit”) are not invalid as obvious under 35 U.S.C. § 103.
The district court also found that the patents-in-suit were
infringed by Par and DRL’s Abbreviated New Drug Appli-
cation (“ANDA”) filings. As a result, Par and DRL were
enjoined from making, using, importing, selling or offer-
ing to sell their generic products in the United States. 1
We affirm the district court’s decision because it did not
err in finding the patents-in-suit not invalid and in-
fringed.
                       BACKGROUND
    Pozen developed a method for treating migraines by
combining two drugs, sumatriptan and naproxen, in a
single tablet. Pozen Inc. v. Par Pharm., Inc., 800 F. Supp.
2d 789, 796 (E.D. Tex. 2011). Sumatriptan, a 5-HT recep-
tor agonist, was developed in the late 1980s and is widely
accepted as an effective medicine for migraines, but it
does not prevent the reoccurrence of migraine symptoms.
Id. at 797. Naproxen is a well known nonsteriodal anti-
inflammatory drug (“NSAID”). Id. at 798. Pozen, in
partnership with GlaxoSmithKline (“GSK”), markets a
combination of sumatriptan and naproxen called Trexi-

    1   After the district court issued its final claim con-
struction order, Pozen stipulated to a judgment of non-
infringement of the ’183 patent in favor of Alphapharm.
Therefore, Alphapharm’s interest in this appeal is limited
to the validity of the ’499 and ’458 patents. Pozen also
sued Teva Pharmaceuticals USA, Inc. (“Teva”) for patent
infringement on the basis of Teva’s ANDA, but the parties
settled before trial. Pozen Inc. v. Par Pharm., Inc., 800 F.
Supp. 2d 789, 796 n.1 (E.D. Tex. 2011).
POZEN INC   v. PAR PHARMA                                  4


met® and holds three related patents relevant to this
appeal. Id. The ’499 patent claims a method of treating
migraines comprising co-timely administration of 5-HT
agonists and long-acting NSAIDs. ’499 patent col.1 ll.13-
17. The ’458 patent is a continuation of the ’499 patent
and claims methods and compositions combining 5-HT
agonists and long-acting NSAIDs. ’458 patent col.1 ll.18-
20. The ’183 patent claims a multilayer pharmaceutical
tablet with a triptan, such as sumatriptan, and a NSAID
in separate layers that dissolve independently. ’183
patent col.1 ll.54-57.
    Pozen filed a New Drug Application (“NDA”) to mar-
ket Treximet® and obtained approval from the United
States Food and Drug Administration (“FDA”) on April
15, 2008. Pozen, 800 F. Supp. 2d at 798. Pozen listed the
patents-in-suit in its NDA as covering Treximet®. The
patents are included in the FDA’s Approved Drug Prod-
ucts with Therapeutic Equivalence Evaluations (known as
“the Orange Book”), see 21 U.S.C. § 355(b)(1), indicating
they could be infringed by the unlicensed manufacture,
use, or sale of Treximet®. Pozen, 800 F. Supp. 2d at 798.
    Appellants are generic pharmaceutical manufacturers
who filed ANDAs with the FDA seeking approval to
market generic forms of Treximet® before the expiration
of Pozen’s patents. Id.; see 21 U.S.C. § 355(b)(2), (j)(2).
Appellants filed their application certifying that the
patents listed in the Orange Book are “invalid or will not
be infringed” by the generic products. 21 U.S.C.
§ 355(j)(2)(A)(vii)(IV); Pozen, 800 F. Supp. 2d at 798-99;
Such a certification constitutes an artificial act of in-
fringement. 35 U.S.C. § 271(e)(2); Warner-Lambert Co. v.
Apotex Corp., 316 F.3d 1348, 1365 (Fed. Cir. 2003).
Thereafter, Pozen filed complaints against Appellants for
infringement of claim 15 of the ’499 patent; claims 11, 12,
24, 26, 27, 29, and 30 of the ’458 patent; and claim 2 of the
5                                  POZEN INC   v. PAR PHARMA


’183 patent under the Hatch-Waxman Act. 2 35 U.S.C.
§ 271(e)(2)(A); Pozen, 800 F. Supp. 2d at 799.
    A. The Relevant ’499 Patent Claims
    The district court found Appellants’ ANDA products
directly infringe Claim 15 of the ’499 patent, which de-
pends on claim 5 and reads:
    5. A therapeutic package for dispensing to, or for
    use in dispensing to, a migraine patient, which
    comprises:
    (a) one or more unit doses, each such unit dose
    comprising:
        (i) a 5-HT agonist and
        (ii) a long-acting, non-steroidal,         anti-
        inflammatory drug (LA-NSAID);
    wherein the respective amounts of said 5-HT ago-
    nist and said LA-NSAID in said unit dose are ef-
    fective, upon concomitant administration to said
    patient of one or more of said unit doses, to reduce
    migraine relapse or produce longer lasting efficacy

    2   It is “an act of infringement to submit . . . an ap-
plication” for approval from the FDA to manufacture “a
drug claimed in a patent.” 35 U.S.C. § 271(e)(2)(A).
Section 271(e)(2)(A) provides that an ANDA constitutes
an artificial act of infringement for which the applicant
may be liable. Warner-Lambert, 316 F.3d at 1365. It
“creates case-or-controversy jurisdiction to enable the
resolution of an infringement dispute before the ANDA
applicant has actually made or marketed the proposed
product.” Id.; see Glaxo, Inc. v. Novopharm, Ltd., 110 F.3d
1562, 1569 (Fed. Cir. 1997). The determination under
§ 271 is the same as any other infringement suit to in-
quire whether a product would infringe a patent if the
ANDA product was on the market. Warner-Lambert, 316
F.3d at 1365.
POZEN INC   v. PAR PHARMA                                  6


    compared to the administration of said 5-HT ago-
    nist in the absence of said LA-NSAID or the ad-
    ministration of said LA-NSAID in the absence of
    said 5-HT agonist, and
    (b) a finished pharmaceutical container therefor,
    said container containing said unit dose or unit
    doses, said container further containing or com-
    prising labeling directing the use of said package
    in the treatment of migraine.
    ....
    15. The improvement, method, or composition of
    claims 1, 2, 3, 4, 5, 6, 7, or 8, wherein said 5-HT
    agonist is sumatriptan, said LA-NSAID is
    naproxen and the unit dosage form is an oral unit
    dosage form comprising sumatriptan in an
    amount greater than 15 mg, and naproxen in an
    amount greater than 200 mg.
’499 patent col.14 ll.1-19; col.15 ll.12-17.
    B. The Relevant ’458 Patent Claims
    The district court found Appellants’ ANDA products
directly infringe claims 11, 12, and 24, which depend on
claim 3, as well as claims 26, 27, 29, and 30, which specify
sumatriptan is the 5-HT agonist and naproxen is the LA-
NSAID used in various dosages. Pozen, 800 F. Supp. 2d
at 806. Representative claim 3 states:
    3. A pharmaceutical composition in unit dosage
    form, useful in treating a migraine headache pa-
    tient, which comprises:
        (a) a 5-HT agonist, wherein said 5-HT agonist
        is a triptan; and
        (b) a long-acting, non-steroidal,          anti-
        inflammatory drug (LA-NSAID),
7                                    POZEN INC   v. PAR PHARMA


        wherein said LA-NSAID has a pharmacoki-
        netic half-life of at least 4 hours and a dura-
        tion of action of at least 6 hours;
    wherein the respective amounts of said 5-HT ago-
    nist and said LA-NSAID in said composition are
    effective, upon concomitant administration to said
    patient of one or more of said unit dosage forms of
    said composition, to produce longer lasting effi-
    cacy compared to the administration of said 5-HT
    agonist in the absence of said LA-NSAID or the
    administration of said LA-NSAID in the absence
    of said 5-HT agonist.
’458 patent col.12 ll.29-45.
    C. The Relevant ’183 Patent Claims
    The district court held that under the doctrine of
equivalents Par and DRL’s ANDA products infringe claim
2 of the ’183 patent, which is dependent on claim 1, and
reads:
    1. A multilayer pharmaceutical tablet comprising
    naproxen and a triptan and, wherein:
        a) substantially all of said triptan is in a first
    layer of said tablet and substantially all of said
    naproxen is in a second, separate layer; and
        b) said first layer and said second layer are in
    a side by side arrangement such that the dissolu-
    tion of said naproxen occurs independently of said
    triptan.
    2. The tablet of claim 1, wherein said naproxen is
    in the form of naproxen sodium between 200 and
    600 mg.
’183 patent col.18 ll.30-39. The court construed the
phrase “substantially all of said triptan is in a first layer
POZEN INC   v. PAR PHARMA                                   8


of said tablet and substantially all of said naproxen is in a
second, separate layer” as meaning “[a]t least 90%, and
preferably greater than 95%, of the total triptan present
in the tablet is included within one distinct layer and at
least 90%, and preferably greater than 95%, of the
naproxen present in the tablet is included within a second
distinct layer.” Pozen, 800 F. Supp. 2d at 809. The parties
agreed that the claim term “dissolution of said naproxen
occurs independently of said triptan” means “[d]issolution
of naproxen . . . and triptan from the multilayer tablet . . .
occurs in the same amount of time ± 10% as when the
same amount of naproxen . . . and triptan are given
separately.” Joint Appendix (“J.A.”) 653.
    D. Procedural History
    Based on the ANDA filings, Pozen filed suit against
Appellants for infringement of the ’499, ’458, and ’183
patents and asked for a permanent injunction against
Appellants from making, using, selling, offering to sell or
importing into the United States their ANDA products
until the patents-in-suit expire. Pozen, 800 F. Supp. 2d at
799. The lawsuit triggered a 30-month stay of FDA
approval for Appellants’ ANDAs. Id.
    Following the claim construction hearing, the district
court conducted a five-day bench trial regarding Pozen’s
infringement claims and Appellants’ noninfringement,
invalidity, and unenforceability defenses and counter-
claims. The district court held, in part, that the patents
were not invalid because they were neither anticipated
nor obvious in light of the prior art, that Appellants’
ANDA products infringed the ’499 and ’458 patents, and
that Par and DRL’s ANDA products infringed the ’183
patent. Id. Furthermore, the district court held that the
’499 patent claims asserted were not invalid due to lack of
written description. Id. at 821-22. Accordingly, the dis-
9                                    POZEN INC   v. PAR PHARMA


trict court enjoined Par, Alphapharm, and DRL from
making or selling their respective ANDA products. Id. at
826. Par, Alphapharm, and DRL filed a timely appeal. 3
We have jurisdiction over the appeals pursuant to 28
U.S.C. § 1295(a)(1).
                        DISCUSSION
    A. Standard of Review
    This court reviews judgments of the district court af-
ter a bench trial “for errors of law and clearly erroneous
findings of fact.” Zenon Envtl., Inc. v. U.S. Filter Corp.,
506 F.3d 1370, 1377 (Fed. Cir. 2007) (citations and inter-
nal quotation marks omitted).
    Appellants challenge the validity of the ’499 and ’458
patents in light of four prior art references. 4 Appellants
also challenge the validity of the ’183 patent in light of the

    3  Par and Alphapharm filed a joint brief, Brief for
Defendants-Appellants Par Pharmaceutical, Inc. and
Alphapharm Pty Ltd. (“Par’s Br.”) and DRL submitted a
separate brief, Brief for Defendant-Appellant Dr. Reddy’s
Laboratories, Inc. (“DRL’s Br.”), adopting in accordance
with Fed. R. App. P. 28(i) Par and Alphapharm’s argu-
ments with regard to invalidity of the ’499, ’458, and ’183
patents over the prior art, DRL’s Br. at 1.
    4  The following references will be discussed below:
Parma, E., et al., The Treatment of Migraine: A Study in
General Medicine, 11 Ricerca & Practica 1995, at 64
(“Parma”); Saadah, H., Abortive Migraine Therapy With
Oral Naproxen Sodium Plus Metoclopramide Plus Ergo-
tamine Tartrate With Caffeine, 32 Headache 1992, at 95
(“Saadah”); Raskin, N., Acute and Prophylactic Treatment
of Migraine: Practical Approaches and Pharmacologic
Rationale, 43 Neurology, June 1993, at 839 (“Raskin”);
Henry Ford Hospital, Patient Records; Catarci et al.,
Ergotamine-Induced Headache Can Be Sustained By
Sumatriptan Daily Intake, 14 Cephalalgia 1994, at 374
(“Catarci”).
POZEN INC   v. PAR PHARMA                                 10


’499 patent and prior art. 5 Appellants ask this court to
hold the ’499 patent invalid for lack of written description.
Additionally, Appellants challenge the district court’s
infringement determination as to the ’183 patent. We
address each argument in turn.
    B. Invalidity
        1. The ’499 And ’458 Patents Are Not Obvious
    A party asserting invalidity must present clear and
convincing evidence to overcome a patent’s presumption of
validity. 35 U.S.C. § 282; Microsoft Corp. v. i4i Ltd.
P’ship, 131 S. Ct. 2238, 2245 (2011). A patent claim is
invalid as obvious “when ‘the differences between the
subject matter sought to be patented and the prior art are
such that the subject matter as a whole would have been
obvious at the time the invention was made to a person
having ordinary skill in the art. . . .”’ KSR Int’l Co. v.
Teleflex Inc., 550 U.S. 398, 406 (2007) (quoting 35 U.S.C.
§ 103(a)). To determine if a patent is obvious the district
court looks to: (1) the scope and content of the prior art;
(2) differences between the prior art and the claims; (3)
the level of ordinary skill in the art; and (4) secondary
considerations such as commercial success and failure of
others. Graham v. John Deere Co., 383 U.S. 1, 17 (1966).
‘“Obviousness is a question of law, reviewed de novo,
based upon underlying factual questions which are re-
viewed for clear error following a bench trial.”’ Aventis
Pharma Deutschland GmbH v. Lupin, Ltd., 499 F.3d
1293, 1300 (Fed. Cir. 2007) (quoting Alza Corp. v. Mylan
Labs., Inc., 464 F.3d 1286, 1289 (Fed. Cir. 2006)).



    5   Bandelin, R., Compressed Tablets by Wet Granula-
tion, 179 Herbert Lieberman et al. eds. (2d ed. 1989)
(“Bandelin”).
11                                  POZEN INC   v. PAR PHARMA


    The district court found that the prior art references
did not invalidate the ’499 and ’458 patents. Specifically,
the district court reasoned that the references did not,
separately or combined, “teach or suggest the simultane-
ous administration of sumatriptan and naproxen. Nor . . .
otherwise disclose to one of ordinary skill in the art that
the combination of sumatriptan and naproxen produces a
longer lasting efficacy reducing migraine relapse com-
pared to the administration of naproxen or sumatriptan
alone.” Pozen, 800 F. Supp. 2d at 819.
    As an initial matter, Par argues that the district court
erred because it failed to apply the term “concomitant
administration” to include simultaneous and sequential
administration as it had been construed. If the district
court had applied the terms as construed, Par asserts, it
would have found the ’499 and ’458 patents invalid be-
cause the prior art showed concomitant administration.
    Within the context of the claim language the district
court properly applied its claim construction. In its
obviousness analysis the district court only referred
directly to whether the references disclosed “simultaneous
administration,” rather than using the broader term
“concomitant administration.” See Pozen, 800 F. Supp. 2d
at 814-19. The district court construed the term “con-
comitantly administering” in the ’499 patent claims as:
     Simultaneous administration; or administration
     of a second drug for migraine relief while a first
     drug for migraine relief is present in a therapeuti-
     cally effective amount; or administration of a 5-
     HT agonist and NSAID such that the effective
     plasma levels of the NSAID will be present in a
     subject from about one hour to about 12-24 hours
     after the onset of migraine or onset of precursor
     symptoms of a migraine.
POZEN INC   v. PAR PHARMA                                12


J.A.2554. The district court construed the term “concomi-
tantly administering” in the ’458 patent claims as “[g]iven
in close enough temporal proximity to allow their individ-
ual therapeutic effects to overlap.” J.A.2555. None of the
parties contested the claim construction. Before the
bench trial the parties agreed that the claim terms “unit
dose form,” “unit doses,” and “unit dosage form(s)” in both
the ’499 and ’458 patents meant “single drug administra-
tion entity(ies).” Every asserted claim in the ’499 and
’458 patents contains the “unit dose” limitation. See ’499
patent col.14 ll.1-15; ’458 patent col.12 ll.29-45. When
considering the claim language as a whole the term “unit
dose” necessarily limits concomitant administration to
mean simultaneous administration because a single drug
administration entity cannot be administered in any other
fashion. See Phillips v. AWH Corp., 415 F.3d 1303, 1314
(Fed. Cir. 2005) (en banc) (“[T]he context in which a term
is used in the asserted claim can be highly instructive.”).
Therefore, the district court properly limited its analysis
of the prior art to whether the references taught simulta-
neous administration of naproxen and sumatriptan.
    Appellants further argue that the ’499 and ’458 pat-
ents should be invalid as obvious in light of the prior art,
asserting that references Parma, Saadah, patient records
from Henry Ford Hospital, or Catarci, alone or in combi-
nation, teach a “concomitant administration” of sumatrip-
tan and naproxen to treat migraines. If the district court
had followed the case law and applied the claim construc-
tion, Appellants contend, it would have found both the
’499 and ’458 patents invalid. We consider each reference
in turn.
             i. The Parma Reference
   The district court determined that the Parma refer-
ence does not render the ’499 and ’458 patents obvious.
13                                  POZEN INC   v. PAR PHARMA


Pozen, 800 F. Supp. 2d at 815-16. We agree. Parma is an
epidemiological survey assessing various migraine treat-
ments entitled, “The Treatment Of Migraine: A Study In
General Medicine.” 6 One of the tables, labeled “Table VI.

     6  At trial, Pozen presented, and the district court al-
lowed into evidence, a declaration from one of the co-
authors of the Parma reference, referred to as the “Tog-
noni declaration,” which stated:
    While my article speaks of [combination therapy]
    of many pairs of drugs, including NSAIDs and
    sumatriptan, this is not meant as a reference to
    administering those two drugs at the same
    time. . . . it refers to the common practice of that
    time of migraine patients taking drugs separately
    in sequence, with a required gap in time between
    administrations of the drugs to determine the effi-
    cacy of the first drug before trying additional
    drugs.
J.A.158512.
    DRL argues that the declaration is inadmissible as
hearsay and irrelevant, and in admitting it the district
court abused its discretion. DRL’s Br. at 52. Pozen argues
that the declaration is admissible under the residual
hearsay rule, Fed. R. of Evid. 807. See Pozen’s Br. at 30.
We review evidentiary determinations under the law of
the regional circuit. Lexion Med. v. Northgate Techs., Inc.,
641 F.3d 1352, 1358 (Fed. Cir. 2011). The Fifth Circuit
reviews decisions to admit or exclude evidence for abuse
of discretion. United States v. Phillips, 219 F.3d 404, 409
(5th Cir. 2000). “The residual hearsay exception is to be
used only rarely, in truly exceptional cases.” United States
v. Walker, 410 F.3d 754, 757 (5th Cir. 2005) (citations and
internal quotation marks omitted). To admit evidence
under the residual hearsay rule, there must be at least
circumstantial guarantees of trustworthiness. Id. at 758.
The Fifth Circuit has found there are equivalent circum-
stantial guarantees of trustworthiness when the declara-
tion is made under oath and the declarant is subject to
the penalties of perjury, the testimony was preserved on
videotape, and the witnesses were subject to cross-
examination. Id. Here, Tognoni made a written state-
POZEN INC   v. PAR PHARMA                                     14


Combinations: 2 drugs,” listed “FANS + sumatriptan”
(FANS is the Italian abbreviation for NSAIDs) among
fifteen other drug combinations for the treatment of
migraines. Another table, labeled “Table VIII. ‘Unsatis-
factory’ treatments,” lists percentages of patients unsatis-
fied with various monotherapy treatments; included in
that list is “sumatriptan.”

   Table VI. Combinations: 2 drugs (53 cases, type 1 and 2)

   FANS + flunarizine                                 13

   FANS + antiemetics                                 5

   FANS + antidepressants                             6

   FANS + ergotamines                                 2

   FANS + analgesics                                  2

   FANS + sumatriptan                                 2

   FANS + FANS                                        1

   FANS + other drugs                                 1

   Ergotamines + benzodiazepine                       1

   Ergotamines + antidepressants                      1


ment under penalty of perjury, but was never subjected to
cross-examination, which may be enough under Fifth
Circuit law to guarantee trustworthiness. However, even
if it is trustworthy, this is not an exceptional case and
thus does not warrant the residual hearsay exception.
See Ortho-McNeil Pharm., Inc. v. Mylan Labs, Inc., 520
F.3d 1358, 1364 (Fed. Cir. 2008).
15                                   POZEN INC   v. PAR PHARMA



     Ergotamines + other drugs                        3

     Sumatriptan + flunarizine                        2

     Sumatriptan + beta-blockers                      1

     Analgesic + analgesic                            2

     Various combinations                             11


J.A.242118.

Table VIII. “Unsatisfactory” treatments (migraine type 1 and 2)

                   Monotherapy Unsatisfactory              %
                               treatments
FANS               118         44
                                                           37.9
Sumatriptan        37              16
                                                           43.2
Analgesics         89              49
                                                           66.0
Ergotamine         18              14
                                                           77.7
derivatives

J.A.242119.
    Appellants’ expert testified that Parma teaches simul-
taneous administration of various drug combinations, and
someone skilled in the art would look at “Table VIII.
‘Unsatisfactory’ treatments” and be motivated to either
administer another agent or administer a combination
therapy. Pozen, 800 F. Supp. 2d at 816. The district court
gave more weight to Pozen’s expert who testified that a
person skilled in the art would have interpreted Parma to
disclose a sequential administration of various drug
POZEN INC   v. PAR PHARMA                                16


combinations. Id. As the tables reproduced above illus-
trate, Parma revealed the types of treatments used and
documented the number of unsatisfactory treatments
reported. Parma only specifies the unsatisfactory results
of monotherapy treatment in Table VIII; it does not
indicate the relative successes of various combination
treatments listed in Table VI. 7 Furthermore, the district
court found that Parma does not disclose anything about
the combination of “FANS + sumatriptan” in particular
reducing migraine relapse or producing longer lasting
efficacy, nor does it disclose the dosage of the combination
treatment. Id. Although the district court abused its
discretion by admitting the Tognoni declaration, see supra
13 n.6, it was harmless error, there was not clear and
convincing evidence that the ’499 and ’458 patents are
obvious over the Parma reference.
             ii. The Saadah Reference
    The Saadah reference is a 1992 report entitled “Abor-
tive Migraine Therapy With Oral Naproxen Sodium Plus
Metoclopramide Plus Ergotamine Tartrate With Caf-
feine.” It discloses the simultaneous delivery of several
components: ergotamine, which is a 5-HT agonist that at
the time was a widely used anti-migraine agent; metoclo-
pramide and caffeine to reduce nausea and improve
“gastric emptying” which in turn leads to better absorp-
tion of anti-migraine agents; and naproxen for its pain
and inflammation reduction effects.
    Par argues that another article, N.H. Raskin’s “Acute
and Prophylactic Treatment of Migraine: Practical Ap-
proaches and Pharmacologic Rationale,” (“Raskin”) shows

   7   Although the properties of the two agents were
known independently, Parma does not give any indication
that the combination of the two produced any benefit
beyond those experienced when each agent is taken alone.
17                                  POZEN INC   v. PAR PHARMA


sumatriptan has beneficial effects on nausea, and can be
used instead of ergotamine to treat migraines eliminating
the need for a concurrent antiemetic. 8 Therefore, Appel-
lants contend, a person of ordinary skill in the art would
reasonably expect to successfully substitute sumatriptan
for ergotamine, both 5-HT agonists, in the treatment plan
disclosed by Saadah. Furthermore, Appellants contend
that in substituting sumatriptan for ergotamine, there
would no longer be a need for antiemetics, so metoclopra-
mide and caffeine would be unnecessary. Accordingly,
Appellants assert, Saadah and Raskin together teach the
simultaneous administration of sumatriptan and
naproxen, rendering the ’499 and ’458 patents obvious.
    Pozen contends that a person of ordinary skill in the
art motivated to substitute sumatriptan for ergotamine
would remove not only metoclopramide and caffeine from
the treatment plan but also naproxen because sumatrip-
tan was recognized to have analgesic and anti-
inflammatory effects. Therefore, Pozen argues, the for-
mulation would result in sumatriptan monotherapy.
     The district court held that after reading Saadah, it is
not obvious that one could substitute sumatriptan for
ergotamine and remove metoclopramide and caffeine as
unnecessary. Pozen, 800 F. Supp. 2d at 817. We agree.
Saadah disclosed each drug as having a specific purpose,
and even though Raskin teaches that antiemetics are
unnecessary with sumatriptan, Raskin does not provide
the motivation to a skilled artisan to substitute one agent
in place of three. Nor does Saadah teach the remaining
efficacy limitations, since it gives no reason to assume
that an entirely different combination of agents would

     8 Raskin teaches that sumatriptan can be used as
an anti-migraine without the concurrent use of anti-
nausea agents. J.A.241903.
POZEN INC   v. PAR PHARMA                                  18


have the same success as the combination disclosed, nor
does it disclose the combination therapy has any added
benefits over any of the components given individually.
See Crocs, Inc. v. Int’l Trade Comm’n, 598 F.3d 1294, 1309
(Fed. Cir. 2010) (“Even if the [patent at issue] were a
combination of known elements according to their estab-
lished functions . . . it yields more than predicable results”
and thus is non-obvious.). The district court did not
clearly err in determining the scope of Saadah and
Raskin. Accordingly, as the district court held, the
Saadah reference does not render the ’499 and ’458 pat-
ents obvious to a person of ordinary skill in the art.
             iii. The Henry Ford Patient Records
    Appellants present two patient records from the
Henry Ford Clinic in Detroit, Michigan, showing doctors
prescribed a daily dose of naproxen as a prophylactic
treatment, and sumatriptan for treating acute migraines.
Appellants argue that because the two agents would be
working in the body at the same time, even if taken
separately, they are concomitantly administered. Addi-
tionally, Appellants contend that a person of ordinary
skill in the art would expect a daily dose of naproxen to
have the same effectiveness as a single dose of naproxen
taken when needed because concentration of the drug in
the blood would be the same or higher. Therefore, Appel-
lants assert that when sumatriptan is taken in addition to
a daily dose of naproxen the combination of the two drugs
would have the same effect as when the two drugs are
given simultaneously.
    Dr. Ramadan, who treated the patients at the clinic,
testified that he did not recall ever prescribing or giving a
patient sumatriptan and naproxen simultaneously.
Furthermore, the Henry Ford Records do not suggest that
it produced longer lasting efficacy or reduced migraine
19                                POZEN INC   v. PAR PHARMA


relapse. At least one of the patients’ prescriptions was
soon altered to sumatriptan and an antidepressant,
suggesting the combination of sumatriptan and naproxen
did not work to relieve migraine symptoms. Accordingly,
the district court did not err in its determination of the
scope of the teachings of the Henry Ford Records; we hold
that the patient records do not render the ’499 and ’458
patents obvious.
           iv. The Catarci Reference
    The Catarci reference is a case report entitled “Ergo-
tamine-Induced Headache Can Be Sustained By Suma-
triptan Daily Intake.” Catarci describes a single patient
who developed ergotamine-induced headaches and subse-
quently replaced ergotamine with daily administration of
sumatriptan.     Sumatriptan effectively alleviated the
patient’s daily migraines but did not relieve her constant
mild headache. Catarci discloses that the patient was
subsequently taken off of sumatriptan and NSAIDs were
“prescribed both on a daily basis and when required.”
Catarci discloses that treating the patient’s acute mi-
graine attacks with either NSAID or sumatriptan was not
beneficial. Instead the patient resumed taking a daily
dose of sumatriptan in addition to acupuncture and
successfully treated acute migraines with additional
sumatriptan. Finally, Catarci concludes that acupuncture
is beneficial “in treating drug-induced daily headache.”
Pozen, 800 F. Supp. 2d at 814 (internal citations and
quotations omitted).
    Appellants argue that Catarci shows a concomitant
administration of sumatriptan and naproxen was used to
treat migraines as evidenced by the patient’s prescription
of a daily NSAID as a prophylactic with sumatriptan used
as needed.
POZEN INC   v. PAR PHARMA                                  20


    The district court did not clearly err in finding that
Catarci does not teach a combination of sumatriptan and
naproxen provided migraine relief.        Rather, Catarci
concludes that the only effective treatment for this patient
was sumatriptan and acupuncture. The district court
determined that Catarci discourages combining sumatrip-
tan and naproxen to achieve the claimed efficacy benefits,
teaching away from the invention. Id.; see In re Gurley, 27
F.3d 551, 553 (Fed. Cir. 1994) (A reference teaches away
when “a person of ordinary skill, upon reading the refer-
ence, would be discouraged from following the path set
out in the reference, or would be led in a direction diver-
gent from the path that was taken by the applicant.”); see
also Spectralytics, Inc. v. Cordis Corp., 649 F.3d 1336,
1343 (Fed. Cir. 2011) (explaining that a jury could find
that prior art taught away from one solution because all
prior art taught a different solution). For the reasons
given by the district court, we agree that the Catarci
reference does not render the ’499 and ’458 patents obvi-
ous.
             v. Conclusion regarding prior art
    We agree with the district court that the prior art
would not have provided one of ordinary skill with moti-
vation to combine sumatriptan and naproxen in order to
benefit from longer lasting efficacy as compared to when
either agent is taken alone. Appellants failed to rebut the
presumption of validity afforded issued patents by clear
and convincing evidence. 35 U.S.C. § 282; Microsoft Corp.,
131 S. Ct. at 2245; see Pfizer, Inc. v. Apotex, Inc., 480 F.3d
1348, 1361 (Fed. Cir. 2007) (“[T]he burden falls on the
challenger of the patent to show by clear and convincing
evidence that a skilled artisan would have been motivated
to combine the teachings of the prior art references to
achieve the claimed invention, and that the skilled arti-
san would have had a reasonable expectation of success in
21                                   POZEN INC   v. PAR PHARMA


doing so.”). Therefore, the prior art references do not
render the ’499 and ’458 patents obvious.
         2. The ’183 Patent Is Not Invalid For Obviousness
    Par asserts, as it did before the district court, that the
’183 patent is obvious in light of the ’499 patent, combined
with Bandelin and/or knowledge of a person of ordinary
skill in the art. Par argues the prior art taught that
naproxen has very low solubility in acidic environments
like the stomach, which would impede the dissolution of
sumatriptan when the two are administered together in a
single unit dose. Therefore, a person of ordinary skill in
the art would use a multilayer tablet, which was well
known, to resolve the physical incompatibility between
sumatriptan and naproxen. Additionally, Par contends
that the district court failed to apply the correct construc-
tion of “independent dissolution” by using the narrow
definition in its invalidity analysis when a plain and
ordinary definition of the term, which Par argues the
district court used to find infringement, would render the
claim obvious.
    The district court explained that although the refer-
ences submitted by Par are different than what was
before the PTO during prosecution, the content of the
references and the arguments made are the same. 9
Pozen, 800 F. Supp. 2d at 820. The district court reasoned
that, considering the record and the arguments:
     It was not obvious to a person of ordinary skill in
     the art to formulate the naproxen sodium and
     sumatriptan into a bilayer configuration. While

     9  The district court considered whether the ’183
patent was obvious is light of the ’499 patent combined
with the Bandelin article that describes how to create and
the advantages of multilayer tablets. Pozen, 800 F. Supp.
2d at 820.
POZEN INC   v. PAR PHARMA                               22


   multilayer tablets were commonly used, Pozen’s
   dosage forms of naproxen sodium and sumatrip-
   tan were not obvious. Nor do the references ren-
   der obvious the specific tablet architecture as
   Pozen argued to the PTO and claimed in the ’183
   patent. Accordingly, Defendants failed to rebut
   the ’183 patent’s presumption of validity by clear
   and convincing evidence.
Id. at 821 (citation omitted). Par concedes that using a
“narrow” interpretation of the term “independent dissolu-
tion” does not invalidate the ’183 patent. We agree.
     Par contends that the district court improperly used a
different construction of “independent dissolution” in its
infringement analysis and invalidity analysis. Par argues
that the district court’s infringement analysis was con-
ducted under the plain and ordinary meaning of the
independent dissolution limitation, whereas the validity
analysis uses a narrower definition. Id. However, Par
fails to explain the “plain and ordinary meaning” of
independent dissolution and identify how it differs from
the “narrow” meaning. In its infringement analysis the
district court construed “independent dissolution” as that
term is defined in the ’183 patent and does not appear to
define that term in its invalidity analysis any differ-
ently. 10 Regardless of what definition is applied, Appel-
lants failed to rebut the presumption of validity afforded
issued patents by clear and convincing evidence. The
district court correctly held that the ’183 patent was not
obvious.




   10   See infra part C(1).
23                                 POZEN INC   v. PAR PHARMA


       3. The ’499 Patent Is Not Invalid For Lack Of Writ-
ten Description
    Appellants argue that the district court erred in find-
ing claim 15 of the ’499 patent not invalid because the
limitations “therapeutic package,” “finished pharmaceuti-
cal container,” and “said container further containing or
comprising labeling directing the use of said package in
the treatment of migraine” lack adequate written descrip-
tion in the specification. Appellants assert that the terms
were added during prosecution and that, although the
exact term need not be recited, “the specification must
contain an equivalent description of the claimed subject
matter,” and there was no description of these limitations.
Lockwood v. Am. Airlines, Inc., 107 F.3d 1565, 1572 (Fed.
Cir. 2007).
    Section 112, paragraph 1 of the Patent Act, requires
that the specification contain a written description of the
invention. 35 U.S.C. § 112, ¶ 1. The purpose of the writ-
ten description requirement is to ensure adequate disclo-
sure of the invention. Ariad Pharms., Inc. v. Eli Lilly &
Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc). 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.” Id. Following a bench trial, we review
compliance with the written description requirement, a
question of fact, for clear error. Tech. Licensing Corp. v.
Videotek, Inc., 545 F.3d 1316, 1332 (Fed. Cir. 2008).
     The ’499 patent discloses several dosage forms, in-
cluding an oral unit dosage, to teach treating migraines
by concomitantly administering therapeutic amounts of
sumatriptan and naproxen. ’499 patent col.3 ll.22-50, col.4
ll.1-4, col.12 ll.54-55, col.15 ll.12-17. The district court
found that “[b]ased on these disclosures, persons of skill
POZEN INC   v. PAR PHARMA                                   24


in the art would know these pharmaceutical dosages are
administered to a patient in containers or packages with
labeling and inserts with dosage instructions.” Pozen, 800
F. Supp. 2d at 821. Specifically, the district court rea-
soned that “[d]ispensing pharmaceutical products in
containers or packages is not a new or unpredictable
concept. A person of ordinary skill in the art would know
that medications are not simply handed out to patients.
Rather, pharmaceutical products, like the claimed tablets,
are routinely administered in containers or packages.” Id.
at 822. Moreover, the FDA requires container labeling
and information for prescription pharmaceutical products.
Id.
    The ’499 patent specification meets the written de-
scription requirement because the specification describes
the invention in such a way that it is understandable to a
person of ordinary skill in the art. See Ariad, 598 F.3d at
1351. As this court has explained, “[i]n order to satisfy
the written description requirement, the disclosure as
originally filed does not have to provide in haec verba
support for the claimed subject matter at issue . . . .
Nonetheless, the disclosure . . . must convey with reason-
able clarity to those skilled in the art that . . . [the inven-
tor] was in possession of the invention.” Purdue Pharma
L.P. v. Faulding Inc., 230 F.3d 1320, 1323 (Fed. Cir.
2000); see LizardTech, Inc. v. Earth Resource Mapping,
Inc., 424 F.3d 1336, 1345 (Fed. Cir. 2005) (“[T]he patent
specification is written for a person of skill in the art, and
such a person comes to the patent with the knowledge of
what has come before . . . . Placed in that context, it is
unnecessary to spell out every detail of the invention in
the specification; only enough must be included to con-
vince a person of skill in the art that the inventor pos-
sessed the invention and to enable such a person to make
and use the invention without undue experimentation.”).
25                                 POZEN INC   v. PAR PHARMA


The district court reasonably found that one skilled in the
art would understand the meaning of “therapeutic pack-
age” and “finished pharmaceutical container.” There is no
clear error in the district court’s finding that there is
adequate written description to support the ’499 patent
validity.
   C. The District Court Did Not Err In Finding That
Appellants’ ANDA Products Infringe The ’183 Patent
    There are two types of infringement: literal infringe-
ment, which is not at issue here, and infringement under
the doctrine of equivalents. 11 “The doctrine of equivalents
allows the patentee to claim those insubstantial altera-
tions that were not captured in drafting the original
patent claim but which could be created through trivial
changes.” Festo Corp. v. Shoketsu Kinzoku Kogyo Kabu-
shiki Co., 535 U.S. 722, 733 (2002). “However, the ‘all
limitations rule’ restricts the doctrine of equivalents by
preventing its application when doing so would vitiate a
claim limitation.” Carnegie Mellon Univ. v. Hoffman-La
Roche Inc., 541 F.3d 1115, 1129 (Fed. Cir. 2008) (quoting
Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520
U.S. 17, 29 (1997)). Equivalence ‘“is not an absolute to be
considered in a vacuum.’” Warner-Jenkinson, 520 U.S. at
24-25 (quoting Graver Tank & Mfg. Co. v. Linde Air
Prods. Co., 339 U.S. 605, 609 (1950)). The essential
inquiry is whether “the accused product or process con-
tain[s] elements identical or equivalent to each claimed
element of the patented invention.” Id. at 40. One way of
proving infringement under the doctrine of equivalents “is
by showing on a limitation by limitation basis that the

     11 To establish literal infringement “every limitation
set forth in a claim must be found in an accused product,
exactly.” Southwall Techs., Inc. v. Cardinal IG Co., 54
F.3d 1570, 1575 (Fed. Cir. 1995). The parties do not
contest literal infringement in this appeal.
POZEN INC   v. PAR PHARMA                                  26


accused product performs substantially the same function
in substantially the same way with substantially the
same result as each claim limitation of the patented
product.” Crown Packaging Tech., Inc. v. Rexam Beverage
Can Co., 559 F.3d 1308, 1312 (Fed. Cir. 2009). We review
the district court’s infringement determinations under the
doctrine of equivalents for clear error. Conoco, Inc. v.
Energy & Env’t Int’l, 460 F.3d 1349, 1357 (Fed. Cir. 2006).
    The district court found that Par and DRL’s ANDA
products infringed claim 2 of the ’183 patent under the
doctrine of equivalents. Pozen, 800 F. Supp. 2d at 812. On
appeal the Appellants challenge the district court’s find-
ings that the Appellants’ ANDA products meet the “inde-
pendent dissolution” limitation and the “substantially all”
limitation. We address each in turn.
        1. The “Independent Dissolution” Limitation
    The parties agreed that the limitation “dissolution of
said naproxen occurs independently of said triptan” as
recited in claim 1 of the ’183 patent means “[d]issolution
of naproxen . . . and triptan from the multilayer tablet . . .
occurs in the same amount of time ± 10% as when the
same amount of naproxen . . . and triptan are given
separately” as it was described in the patent specification.
J.A.653; ’183 patent col.2 ll.48-54. Based on the evidence
presented the district court found “Pozen has shown by a
preponderance of the evidence the accused ANDA prod-
ucts achieve independent dissolution.” Pozen, 800 F.
Supp. 2d at 811-12.
    Relying upon Par’s FDA filings and expert testimony
presented at trial, the district court found that Par’s
ANDA product performs the same function in the same
way to achieve the same results and therefore satisfies
the independent dissolution limitation under the doctrine
of equivalents. Pozen, 800 F. Supp. 2d at 810. Pozen’s
27                                 POZEN INC   v. PAR PHARMA


expert noted that Par’s ANDA product was specifically
formulated to achieve complete and independent dissolu-
tion. J.A.6029. Moreover, in its ANDA, Par represented
to the FDA that the sumatriptan and naproxen in its
ANDA product dissolves completely and independently
from each other. J.A.157587; J.A.157602; J.A.158055. 12
    The district court similarly found that DRL’s ANDA
product achieves independent dissolution “by the way it
formulates and manufactures the tablets.” Pozen, 800 F.
Supp. 2d at 810. Relying upon the parties’ ANDA disclo-
sures and expert testimony, the district court found that
“substantially all the triptan is segregated and separated
into the equivalent of a first distinct layer, in an equiva-
lent side-by-side arrangement, and this achieves the
result of independent dissolution.” Id. at 811. Moreover,
the district court found “DRL’s testing of its ANDA prod-
uct confirms its independent dissolution.” Id. 13


     12 Par’s ANDA states:
    Most of our experiments were targeted to match
    the in-vitro dissolution profile of the individual
    brands. Naproxen Sodium, is poorly soluble in
    lower pH conditions, and tends to form a gel like
    matrix and thereby retard the release of co-
    administered drugs. Our primary objective is to
    develop a formulation having minimal effect of
    Naproxen Sodium over Sumatriptan Succinate
    dissolution, thereby having release profiles inde-
    pendent of each other in all the pH conditions. . . .
J.A.157602.
    13  Comparing DRL’s dissolution profile of its ANDA
product to Table 7 in the ’183 patent, which shows the
dissolution profile of sumatriptan in a bilayer tablet,
Pozen’s expert, Dr. Williams, opined that the dissolution
results in the table were almost the same as those in
DRL’s ANDA product. J.A.6063-64.
POZEN INC   v. PAR PHARMA                                 28


    Notwithstanding the evidence presented at trial, Ap-
pellants argue that Pozen did not prove independent
dissolution because there is no evidence on the record that
the comparison required by the ’183 patent was ever
undertaken. Specifically, Appellants contend that there is
no proof that the independent dissolution achieved by the
ANDA products was compared to dissolution rates of the
same amount of naproxen or sumatriptan alone. Appel-
lants thus ask this court to find the district court erred by
not requiring any proof that the active agents in their
ANDA products achieved dissolution in about the same
time (± 10%) it would take for either of the active agents
to achieve dissolution when taken alone.
    The district court did not clearly err in finding in-
fringement under the doctrine of equivalents because the
record contains sufficient evidence that the independent
dissolution requirement of the ’183 patent was met. In
assessing equivalents, the court considers whether “the
accused product[s] perform[] substantially the same
function in substantially the same way with substantially
the same result as each claim limitation of the patented
product.” Crown Packaging Tech., 559 F.3d at 1312.
Although there is no direct evidence comparing the rate of
dissolution of the ANDA products to that of the agents
individually, no such actual comparison was necessary.
Under the doctrine of equivalents analysis Pozen need
only show that the ANDA products performed the same
function in the same way to achieve the same result as
the claimed elements of the ’183 patent. Par and DRL
provided expert testimony to show that the sumatriptan
dissolves completely and independently from the
naproxen and that the naproxen dissolves completely and
independently from the sumatriptan in their ANDA
products. Also, there is probative evidence from Par’s
ANDA and comparison of DRL’s ANDA products dissolu-
29                                 POZEN INC   v. PAR PHARMA


tion profile showing that their sumatriptan and naproxen
dissolve completely and independently from another. As
a result, Appellants offer no basis for setting aside the
district court’s finding. Indeed, there is sufficient evi-
dence showing that logically if the agents dissolve in the
same way they would if the other agent was not present,
their dissolution takes the same amount of time it would
taken when given separately. Thus, the district court did
not clearly err in relying on Pozen’s expert testimony and
concluding that Appellants’ ANDA products meet the
“independent dissolution” limitation as recited in claim 1
of the ’183 patent under the doctrine of equivalents.
       2. Infringement Of The “Substantially All” Limita-
tion
     Claim 1 of the ’183 patent requires “substantially all
of said triptan is in the first layer of said tablet and
substantially all of said naproxen is in a second, separate
layer.” ’183 patent col.18 ll.30-39. The district court
construed this phrase as “at least 90%, and preferably
greater than 95%, of the total triptan present in the tablet
is included within one distinct layer and at least 90%, and
preferably greater than 95%, of the naproxen present in
the tablet is included within a second distinct layer.”
Pozen Inc. v. Par Pharm., Inc., 719 F. Supp. 2d 718, 734
(E.D. Tex. 2010). It is undisputed that the first layer of
Par’s ANDA tablet “contains 100% of the tablet’s suma-
triptan, along with 15% of the tablet’s naproxen, with the
remaining 85% of the naproxen in the second layer.
DRL’s ANDA tablet has 100% of the tablet’s naproxen and
15% of the tablet’s sumatriptan in the first layer, with the
remaining 85% of the sumatriptan in the second layer.”
Pozen, 800 F. Supp. 2d at 809.
POZEN INC   v. PAR PHARMA                                30


           i. The doctrine of equivalents can apply to the
“substantially all” limitation
    The district court recognized that the claim construc-
tion of the term “substantially all” provided specific
percentages but stated that “absent more limiting lan-
guage in the intrinsic record” the doctrine of equivalents
can be applied to find infringement where the accused
value is insubstantially different from the claimed value.
Id. (quoting Adams Respiratory Therapeutics, Inc. v.
Perrigo Co., 616 F.3d 1283, 1292 (Fed. Cir. 2010)); see also
U.S. Philips Corp. v. Iwasaki Elec. Co., 505 F.3d 1371,
1378 (Fed. Cir. 2007) (holding that despite a claimed
concentration range the doctrine of equivalents can still
be applied).
    Par argues that the district court improperly treated
the claim term “substantially all” as a precise quantity
entitled to the doctrine of equivalents when it is really a
“fuzzy” quantitative limitation not entitled to equivalents.
Par asserts that the word “substantially” was used to
capture values lower than 100%, indeed the district court
construed the term to include any amount as low as 90%,
and Par contends Pozen should not reach below 90% “to
encompass equivalents of equivalents.” Cohesive Techs.,
Inc. v. Waters Corp., 543 F.3d 1351, 1372 (Fed. Cir. 2008).
    DRL argues that the district court erred in granting
Pozen a range of equivalency for the ’183 patent beyond
the scope of equivalency determined through claim con-
struction. DRL asserts that in the cases the district court
cites the degree to which the accused product fell outside
the specifically claimed range was miniscule in compari-
son to the amount their ANDA product falls outside of the
claimed range. 14 Here, DRL contends, sumatriptan only

   14   In Adams Respiratory the requirement was “at
least 3500 units” and the accused product had 3493.38
31                                 POZEN INC   v. PAR PHARMA


makes up 85% of one layer; 5% less than the minimum
90% set forth in the construction of the term “substan-
tially all.”
     Indeed, this court has stated that where “a patentee
has brought what would otherwise be equivalents of a
limitation into the literal scope of the claim, the doctrine
of equivalents is unavailable to further broaden the scope
of the claim.” Cohesive Techs., 543 F.3d at 1372. “[A]ll
claim limitations are not entitled to an equal scope of
equivalents. Whether the result of the All Limitations
Rule, prosecution history estoppel, or the inherent nar-
rowness of the claim language, many limitations warrant
little, if any, range of equivalents.” Moore U.S.A., Inc. v.
Standard Register Co., 229 F.3d 1091, 1106 (Fed. Cir.
2000) (internal citations omitted).
    However, although the claim language itself is a
qualitative measure, the claim construction pulls directly
from the specification to give the term “substantially all”
a quantitative definition, specifically, “at least 90%, and
preferably greater than 95%,” ’183 patent col.2 ll.62-65,
and this court has previously concluded that the doctrine
of equivalents is not foreclosed with respect to claimed
ranges, see Adams Respiratory, 616 F.3d at 1291-92. In
Kemin Foods, the court construed “substantially free from
other carotenoids” to mean “significantly less than 10% of
other carotenoids” based, in part, on the specification
stating that “[g]enerally, the concentration of other caro-
tenoids in the starting material should be 10% or less.”
Kemin Foods, L.C. v. Pigmentos Vegetales Del Centro S.A.

units, within 0.189% of the claimed minimum. Adams
Respiratory, 616 F.3d at 1291. In Abbott Laboratories, the
claim required between 68.8% and 94.5% by weight of a
component, and the accused product had 95% of that
component. Abbott Laboratories v. Dey L.P., 287 F.3d
1097, 1107 (Fed. Cir. 2002).
POZEN INC   v. PAR PHARMA                                32


de C.V., 464 F.3d 1339, 1349 (Fed. Cir. 2006). The court
determined that because Kemin did not argue that “sig-
nificantly less than 10%” has a precise upper limit a
reasonable person could determine that a concentration of
6.14%-9.86% does not infringe under the doctrine of
equivalents. Id.    Similarly, in this case, Pozen never
stated that “at least 90%, and preferably greater than
95%” should be an absolute floor. Under the doctrine of
equivalents a tablet layer with 85% of the agent can be
fairly characterized as an insubstantial change from a
tablet layer with 90% of the agent.
           ii. Appellants’ ANDA products infringe the
“substantially all” limitation under the doctrine of equiva-
lents
    Turning now to the district court’s analysis of in-
fringement of the “substantially all” limitation, we review
the district court’s findings of infringement under the
doctrine of equivalents for clear error. Conoco, 460 F.3d at
1357. The district court stated that the multilayer tablet
claimed in the ’183 patent requires “substantially all of
the naproxen and triptan [to be] segregated and separated
for the purpose of independent dissolution.” Pozen, 800 F.
Supp. 2d at 810. The parties’ experts agreed that the
function was to have “separate, distinct layers of suma-
triptan and naproxen. The way in which this function is
achieved is by formulating the sumatriptan and naproxen
in different manners to create physical barriers. The
result is that substantially naproxen is separated from
the [sumatriptan], thereby providing independent dissolu-
tion.” Id.
    The district court found that Par’s ANDA product per-
forms essentially the same function, by segregating the
naproxen and sumatriptan into two layers. Id. This is
achieved by formulating them differently, specifically, by
33                                  POZEN INC   v. PAR PHARMA


using a polymer binder to form 15% of the naproxen into
granules which are added to the sumatriptan layer. Id.
The result is that one layer has 100% of the sumatriptan
with 15% of the naproxen, and another layer has the
remaining 85% of the naproxen, substantially all sepa-
rated and segregated into two layers. Id. Therefore, the
district court determined, Par’s ANDA product performs
the same function, in the same way, and achieves the
same result, and satisfies all of the limitations of the ’183
patent under the doctrine of equivalents.
    The district court also found that DRL’s ANDA prod-
uct performs the same function of achieving separate,
distinct layers by segregating the triptan and naproxen.
Id. This is achieved by granulating 15% of the sumatrip-
tan with a polymer binder and then spraying it on the
naproxen which has been granulated with a polymer
binder as well; the remaining 85% of the sumatriptan
forms the other layer. Id. “Thus, substantially all the
triptan is segregated and separated into the equivalent of
a first distinct layer, in an equivalent side-by-side ar-
rangement, and this achieves the result of independent
dissolution.” Id. at 811. Therefore, the district court
determined, DRL’s ANDA product performs the same
function, in the same way, and achieves the same result,
and satisfies all of the limitations of the ’183 patent under
the doctrine of equivalents.
     Appellants argue that their ANDA products do not
achieve separate distinct layers because one of the layers
has both agents. However, their products contain a
bilayer tablet, with 100% of one agent in one layer, and
85% of the other agent in the other layer. We determine,
as the district court did, that this structure is insubstan-
tially different from a bilayer tablet with 90% of the total
therapeutic agent present in the tablet included in a
single layer.
POZEN INC   v. PAR PHARMA                                34


    Appellants contend that their products are admix-
tures which Pozen specifically disclaimed during the ’183
patent prosecution. DRL argues that the district court
improperly limited Pozen’s disclaimer to admixtures that
achieve independent dissolution, when it really dis-
claimed admixtures in general. We agree that Pozen did
in fact disclaim admixtures when it stated before the
PTO:
   The present claims require that naproxen and
   [sumatriptan] be in a tablet in which they are seg-
   regated from one another in a “side by side ar-
   rangement” and in which their dissolution occurs
   independently of one another. The claims are lim-
   ited to one very specific tablet architecture.
   Among the dosage forms falling outside the claims
   are: admixtures; any dosage forms other than tab-
   lets; tablets in which one drug is in a core and
   surrounded by a layer or coating containing the
   second drug; and tablets containing multiple drug
   release pellets or microparticles.
J.A.240667. However, the Appellants’ ANDA products
are not admixtures, i.e. substances with blended or mixed
ingredients, because substantially all of the agents are
separated and segregated into two distinct layers, as
explained above.
    Based on the evidence above, the district court did not
clearly err in finding that Par’s ANDA products and
DRL’s ANDA products met the “substantially all” limita-
tion of the ’183 patent under the doctrine of equivalents.
                        CONCLUSION
    Appellants failed to rebut the presumption of validity
of issued patents, thus, we affirm the district court’s
holding that the ’499, ’458, and ’183 patents are not
35                                 POZEN INC   v. PAR PHARMA


invalid. Additionally the Appellants provided no basis for
unsettling the district court’s finding on infringement.
Accordingly, we affirm the district court’s injunction
enjoining Appellants from making, using, importing,
selling or offering to sell their ANDA products, or induc-
ing others to do so, until the expiration of the ’499, ’458,
and ’183 patents.
                       AFFIRMED
  United States Court of Appeals
      for the Federal Circuit
               __________________________

                     POZEN INC.,
                    Plaintiff-Appellee,
                            v.
           PAR PHARMACEUTICAL, INC.,
                Defendant-Appellant,
                           AND

        DR. REDDY’S LABORATORIES, INC.,
               Defendant-Appellant,
                           AND

              ALPHAPHARM PTY LTD.,
                 Defendant-Appellant.
               __________________________

                 2011-1584, -1585, -1586
               __________________________

   Appeal from the United States District Court for the
Eastern District of Texas in Consolidated Case Nos. 08-
CV-0437, 09-CV-0003, and 09-CV-0182, Judge Leonard
Davis.
              __________________________

CLEVENGER, Circuit Judge, dissenting-in-part.
    I join the court’s opinion in all respects but one. The
District Court erred in finding infringement of claim 2 of
the ’183 patent under the doctrine of equivalents, and the
POZEN INC   v. PAR PHARMA                                2


court today errs in sustaining the judgment of the District
Court on this issue.
    Claim 2 calls for a multilayer pharmaceutical tablet
comprising naproxen and a triptan wherein “substantially
all of said triptan is in a first layer of said tablet and
substantially all of said naproxen is in a second, separate
layer.” This claim language begged the question of how
much by volume of both naproxen and triptan less than
100% is “substantially all.” The District Court answered
the question, construing “substantially all” without objec-
tion to mean:
       “[A]t least 90%, and preferably greater than
       95%, of the total triptan
       present in the tablet is included within one
       distinct layer and at least
       90%, and preferably greater than 95%, of the
       naproxen present in
       the tablet is included within a second distinct
       layer.”
The accused products do not literally meet the “substan-
tially all” limitation. That is why the patentee could not
assert literal infringement of claim 2, and why he was
forced to rely on the doctrine of equivalents to establish
infringement. The actual composition of the claimed and
accused tablets, with regard to the “substantially all”
limitation, is shown on the following chart.
3                                   POZEN INC   v. PAR PHARMA



             Claimed       Par’s ANDA      DRL’s ANDA
             Product        product         product

          ≥90% total      ~100% total
          amt. of         amt. of
          sumatrip-       sumatriptan,     ~85% total
    Layer tan,
                          ~15% total       amt. of suma-
      1
          ≤10% total      amt. of          triptan
          amt. of         naproxen
          naproxen        (granules)

                                           ~100% total
                                           amt. of
          ≥90% total
                                           naproxen
          amt. of
                          ~85% total       (granules),
    Layer naproxen,
                          amt. of          ~15% total
      2   ≤10% total      naproxen         amt. of suma-
           amt. of
                                           triptan
           sumatriptan
                                           (sprayed on
                                           granules)


    As shown in the table above, each of the Par and DRL
products includes one more or less “pure” layer meeting
the “substantially all” limitation as defined by the District
Court. Par’s product has substantially all the required
triptan in one layer along with 15% of the tablet’s
naproxen, but the second Par layer has less than 90% of
naproxen. So the question is whether 85% of naproxen is
equivalent to 90%, when “substantially all” means “at
least 90% and preferably greater than 95%.
POZEN INC   v. PAR PHARMA                                  4


     DRL’s product is also designed to avoid the “substan-
tially all” limitation. It has substantially all the required
naproxen in one layer, along with 15% of the triptan, but
the second DRL layer has only 85% of the total triptan in
the product. So, again, the question is whether 85% can
be “substantially all” given the District Court’s construc-
tion of the limitation.
     Pozen candidly admits in its brief to this court that
the District Court never directly addressed the question of
whether a layer containing 85% of a necessary ingredient
is an equivalent of a layer containing at least 90% and
preferably 95% of the necessary ingredient. And Pozen
says it does not argue that 85% can be a numerical
equivalent of 90%. Instead, Pozen argues that the Dis-
trict Court properly elided the numeric equivalence issue
by asking only if the accused products had an “equivalent
of a second layer” which could be viewed as containing
substantially all of the required ingredient. Pozen and
the District Court both see the “substantially all” limita-
tion as requiring the tablet to have one more or less pure
layer, and not an actual second layer but an “equivalent”
second layer that could be said to be equivalent to a more
or less pure layer even if it failed to contain substantially
all of the required ingredient. In short, Pozen and the
District Court used the notion of an equivalent layer
simply to avoid answering the question of whether 85% is
the equivalent of 90% or preferably 95%.
    Even if the equivalent layer notion has merit, it still
cannot be disconnected from the language of the claim.
The equivalent layer would, in any event, have to be the
equivalent of a more or less pure layer, i.e., one with at
least 90% and preferably 95% of the required ingredient
in it. How can a layer with only 85% of the necessary
ingredient in it be an equivalent of a layer with at least
90% and preferably 95% of the required ingredient in it?
5                                  POZEN INC   v. PAR PHARMA


    The District Court, with no contest from Pozen, rec-
ognized that “substantially all” inherently contains a
range from something less than 100% up to 100%. Rather
than leave the inherent equivalent range embedded in the
claim language, the District Court put boundaries on the
claim language. “Substantially all” means at least 90%
and preferably 95%. The defendants cite our precedent,
including Moore U.S.A., Inc. v. Standard Register Co., 229
F.3d 1091 (Fed. Cir. 2000), for the proposition that the
spread from 85% to 90% is too great to be an equivalent.
Pozen appreciates the force of those cases, but argues they
are inapplicable here because the District Court did not
answer the numeric equivalence question but instead
turned the infringement decision on a flawed layer
equivalence notion.
    In my view, the District Court erred by not asking it-
self if under claim 2 a layer, viewed from the outside or
from the inside, can be equivalent if is numerically non-
equivalent. It cannot. The majority states that “a rea-
sonable person could determine that a tablet layer with
85% of the agent is within the scope of the doctrine of
equivalents.” Respectfully, I disagree.
