       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

              ALLERGAN SALES, LLC,
               Plaintiff-Cross-Appellant

                           v.

  SANDOZ, INC., ALCON LABORATORIES, INC.,
          ALCON RESEARCH, LTD.,
             Defendants-Appellants
            ______________________

      2017-1499, 2017-1500, 2017-1558, 2017-1559
               ______________________

    Appeals from the United States District Court for the
Eastern District of Texas in Nos. 2:12-cv-00207-JRG,
2:15-cv-00347-JRG, Judge J. Rodney Gilstrap.
                ______________________

              Decided: December 22, 2017
                ______________________

    JONATHAN ELLIOT SINGER, Fish & Richardson, PC,
San Diego, CA, argued for plaintiff-cross-appellant. Also
represented by SUSAN E. MORRISON, ROBERT M. OAKES,
Wilmington, DE; DEANNA JEAN REICHEL, Minneapolis,
MN.

   JOHN C. O’QUINN, Kirkland & Ellis LLP, Washington,
DC, argued for defendants-appellants. Also represented
2                        ALLERGAN SALES, LLC   v. SANDOZ, INC.



by SEAN M. MCELDOWNEY, CALVIN ALEXANDER SHANK;
BRYAN SCOTT HALES, Chicago, IL.
              ______________________

    Before MOORE, MAYER, and HUGHES, Circuit Judges.
HUGHES, Circuit Judge.
    Allergan Sales, LLC sued generic drug manufacturers
under the Hatch-Waxman Act, alleging infringement of
U.S. Patent Nos. 7,030,149, 7,320,976, and 8,748,425.
The U.S. District Court for the Eastern District of Texas
found the asserted claims not invalid but only claims of
the ’425 patent infringed. We find no reversible error in
the district court’s finding of no invalidity. Nevertheless,
because we find that the accused proposed generic drug
contemplates administering dosages of a specific composi-
tion that is not claimed in any of the patents, we affirm-
in-part and reverse-in-part.
                             I
    Allergan holds the approved new drug application for
Combigan®, which is used to lower intraocular pressure
in glaucoma and ocular hypertension patients.
Combigan® is a “fixed combination” ophthalmic solution
consisting of 0.2% brimonidine tartrate and 0.68% timolol
maleate for twice-daily dosage.
    Allergan claims that the ’149, ’976, and ’425 patents
cover Combigan®. These patents share a common specifi-
cation, which describes: (1) a “Brimonidine Tartrate
0.20% (w/v)” and “Timolol Maleate 0.68% (w/v) (Equiva-
lent to 0.50% (w/v) timolol)” pharmaceutical composition;
and (2) a clinical study using that composition for twice
daily administration. See, e.g., J.A. 347–50. In particu-
lar, Allergan claims that claim 4 of the ’149 patent,
claim 1 of the ’976 patent, and claims 1–8 of the ’425
patent protect Combigan® and its administration.
ALLERGAN SALES, LLC   v. SANDOZ, INC.                     3



    Claim 4 of the ’149 patent recites a method of reduc-
ing the number of daily administrations of 0.2% brimoni-
dine and 0.5% timolol in a single composition from three
times a day to two times a day “without loss of efficacy.”
J.A. 350.
    Claim 1 of the ’976 patent recites a method of admin-
istering “a therapeutically effective amount” of composi-
tion comprising 0.2% brimonidine and 0.5% timolol twice
daily. J.A. 356.
    Claim 1 of the ’425 patent recites administering twice
daily a single combination comprising 0.2% brimonidine
tartrate and 0.5% timolol free base to “reduce[] the inci-
dence of one or more adverse events” listed in the claim.
J.A. 366. Claims 2–8 of the patent depend from claim 1,
each specifically reciting only one of the adverse events
enumerated in claim 1. Id.
    Sandoz, Inc., Alcon Laboratories, Inc., and Alcon Re-
search, Ltd. (collectively, Sandoz) filed and maintained an
abbreviated new drug application (ANDA) with the U.S.
Food and Drug Administration, seeking its approval to
market generic versions of Combigan®. Allergan sued
Sandoz for direct, induced, and contributory infringement,
asserting numerous patents in three different actions,
only the last two of which proceeded to a consolidated
bench trial on the ’149, ’976, and ’425 patents.
    The district court found the asserted claims of the pa-
tents not invalid as obvious. The court also found that
claim 4 of the ’149 patent satisfies the written description
requirement. The court finally determined that Sandoz’s
ANDA does not infringe claim 4 of the ’149 patent or
claim 1 of the ’976 patent, but does infringe claims 1–8 of
the ’425 patent.
    Sandoz appeals the district court’s no-invalidity and
infringement determinations. Allergan cross-appeals the
4                        ALLERGAN SALES, LLC   v. SANDOZ, INC.



finding of non-infringement. We have jurisdiction under
28 U.S.C. § 1295(a)(1).
                             II
    We review the district court’s legal determinations de
novo and factual findings for clear error. Braintree Labs.,
Inc. v. Novel Labs., Inc., 749 F.3d 1349, 1358 (Fed. Cir.
2014). Obviousness is a question of law that we review de
novo, and we review any underlying factual questions for
clear error. Honeywell v. United States, 609 F.3d 1292,
1297 (Fed. Cir. 2010). “Whether a claim satisfies the
written description requirement is a question of fact that,
on appeal from a bench trial, we review for clear error.”
Alcon Res. Ltd. v. Barr Labs., Inc., 745 F.3d 1180, 1190
(Fed. Cir. 2014). Infringement is a question of fact that
we review for clear error. Id. at 1186.
                             A
     Sandoz first argues that all asserted claims are inva-
lid as obvious. A claim is invalid if, at the time the inven-
tion was disclosed, a person having ordinary skill in the
art would have found the patented invention obvious in
light of the prior art. See 35 U.S.C. § 103; KSR Int’l Co. v.
Teleflex, Inc., 550 U.S. 398, 415–16 (2007). But patents
are presumed to be valid and overcoming that presump-
tion requires clear and convincing evidence. 35 U.S.C.
§ 282; Microsoft Corp. v. i4i Ltd. P’ship, 564 U.S. 91, 95
(2011).
     The district court found the asserted claims not inva-
lid as obvious, reasoning that Sandoz presented substan-
tially the same arguments and evidence in an earlier
dispute with Allergan in which we held that claim 4 of the
’149 patent recited an efficacy limitation that is neither
suggested nor inherent in any prior art in the record. J.A.
74–76; see also Allergan, Inc. v. Sandoz Inc., 726 F.3d
1286, 1293–94 (Fed. Cir. 2013). Relying on that preceden-
tial decision, the court found that all asserted claims
ALLERGAN SALES, LLC   v. SANDOZ, INC.                      5



recited analogous efficacy limitations, neither suggested
nor inherent in prior art produced by Sandoz. J.A. 163.
     Sandoz contends that the court erred because the as-
serted claims merely recite the inherent results of admin-
istering an obvious combination. We disagree. As we
concluded in the earlier dispute regarding claim 4 of the
’149 patent, the concomitant administration of brimoni-
dine and timolol ophthalmic composition twice daily is
obvious in view of the prior art. See J.A. 122–25; Aller-
gan, 726 F.3d at 1294. Each asserted claim, however,
expressly recites an additional efficacy limitation that
further restricts the method of administering the compo-
sition twice daily: (1) “without loss of efficacy” in claim 4
of the ’149 patent, see J.A. 350; (2) “a therapeutically
effective amount” in claim 1 of the ’976 patent, see J.A.
356; and (3) “reduc[ing] the incidence of one or more
adverse events” in claim 1 of the ’425 patent,1 see J.A.
366. See also Allergan, 726 F.3d at 1293. Those efficacy
limitations are not disclosed by any prior art reference in
the record. To the contrary, the prior art shows that the
combination dosed twice daily produces a loss of efficacy
in the afternoon. J.A. 107–116; see also Allergan, 726
F.3d at 1294. The efficacy limitations are also not inher-
ent in the administration of the ophthalmic composition, a
finding adequately supported by the record. See, e.g., J.A.
2572–75, 3007–09, 3117–19, 3243–45. Accordingly, the
asserted claims merely recite those administrations of the
composition that satisfy the efficacy limitations—but not
those that end up in, for example, a loss of efficacy, exam-
ples of which abound in the prior art offered by Sandoz.
    In light of the foregoing, the district court did not err
by finding that Sandoz failed to present clear and convinc-


    1  Claims 2–8 include similar limitations, but each
claim specifically recites only one of the adverse events
enumerated in claim 1. See J.A. 366.
6                        ALLERGAN SALES, LLC   v. SANDOZ, INC.



ing evidence to overcome the presumption that the assert-
ed claims are valid.
                              B
    Sandoz next argues that claim 4 of the ’149 patent is
invalid for lack of written description in the specification
based on its expert testimony that the claim encompasses
hundreds of brimonidine and timolol combinations.
    The written description requirement provides that a
patentee’s application for a patent must “clearly allow
persons of ordinary skill in the art to recognize that [he]
invented what is claimed.” Ariad Pharm., Inc. v. Eli Lilly
& Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc)
(quoting Vas–Cath Inc. v. Mahurkar, 935 F.2d 1555, 1563
(Fed. Cir. 1991)). “[T]he test for sufficiency is whether the
disclosure of the application relied upon reasonably
conveys to those skilled in the art that the inventor had
possession of the claimed subject matter as of the filing
date.” Id. Relevant here, a sufficient description of a
genus requires the “disclosure of either a representative
number of species falling within the scope of the genus or
structural features common to the members of the genus
so that one of skill in the art can visualize or recognize the
members of the genus.” Id. at 1350. Even a single repre-
sentative embodiment can support written description of
a claimed genus. See, e.g., Invitrogen Corp. v. Clontech
Labs., Inc., 429 F.3d 1052, 1073 (Fed. Cir. 2005); Bilstad
v. Wakalopulos, 386 F.3d 1116, 1124–25 (Fed. Cir. 2004).
    Claim 4 of the ’149 patent recites 0.2% brimonidine
and 0.5% timolol. J.A. 350. Given the construction of the
terms brimonidine and timolol to include their free base
and salt forms, see J.A. 1594, 1597, the district court
correctly credited Allergan’s expert testimony at trial that
a person of ordinary skill in the art would have under-
stood the claim to encompass only six possible combina-
tions of brimonidine and timolol and their respective free
base and salt forms, see J.A. 150—not, as Sandoz claims,
ALLERGAN SALES, LLC   v. SANDOZ, INC.                    7



hundreds of combinations. More critically, the specifica-
tion discloses one of those six possible combinations, 0.2%
brimonidine tartrate and 0.68% timolol maleate composi-
tion. See J.A. 347. Tellingly, Sandoz’s expert failed to
identify any additional composition beyond that particu-
lar combination. J.A. 150–51. It was also undisputed at
trial that the only salt of brimonidine available as of the
filing of the ’149 patent was brimonidine tartrate and that
only one salt of timolol actually available—timolol male-
ate. J.A. 151–52. The specification therefore discloses a
representative—indeed, the sole—embodiment of the
claimed genus and a person of ordinary skilled in the art,
reading the specification, would have immediately dis-
cerned the claimed limitation. Accordingly, the district
court did not err by finding that the claim satisfies the
written description requirement.
                              C
    Sandoz finally argues that the district court erred in
finding infringement of claims 1–8 of the ’425 patent.
Allergan asserted only literal infringement of those
claims. “To establish literal infringement, every limita-
tion set forth in a claim must be found in an accused
product, exactly.” Advanced Steel Recovery, LLC v. X-
Body Equip., Inc., 808 F.3d 1313, 1319 (Fed. Cir. 2015)
(quoting Southwall Techs., Inc. v. Cardinal IG Co., 54
F.3d 1570, 1575 (Fed. Cir. 1995)).
     The district court found that the proposed generic
contains 0.5% timolol free base and therefore infringed
the claims of the ’425 patent. J.A. 116–18, 158. That
finding is erroneous for two related reasons. Claims 1–8
are narrowly and specifically drawn, reciting administra-
tion of 0.2% brimonidine tartrate and 0.5% timolol free
base. J.A. 366. Both Combigan® and the proposed gener-
ic, however, contain 0.68% timolol maleate, an ophthalmic
compound distinct from 0.5% timolol free base. See, e.g.,
J.A. 2786–87 (Sandoz’s expert explaining why the pro-
8                       ALLERGAN SALES, LLC   v. SANDOZ, INC.



posed generic does not contain 0.5% timolol free base).
The district court relied on the equivalency of the two
compounds in finding literal infringement—that is, 0.5%
timolol free base recited in claims 1–8 as chemically
equivalent to 0.68% timolol maleate contained in the
proposed generic. See J.A. 117, 158. Because chemical
equivalency is not sufficient for literal infringement of
these claims, the court clearly erred.
    The Hatch-Waxman Act provides for a technical in-
fringement upon submission of an ANDA, but only “for a
drug claimed in a patent.” 35 U.S.C. § 271(e)(2)(A). Here,
Combigan® contains a 0.2% brimonidine tartrate and
0.68% timolol maleate solution, as its FDA-approved label
makes clear. J.A. 2310; see also J.A. 116–17. But claims
1–8 of the ’425 patent expressly recite 0.5% timolol free
base, not 0.68% timolol maleate. Therefore, as a matter of
law, Combigan® is not the “drug claimed in” the ’425
patent, and Sandoz’s ANDA does not infringe under
§ 271(e)(2)(A). See also Warner-Lambert Co. v. Apotex
Corp., 316 F.3d 1348, 1354 (Fed. Cir. 2003) (“[I]t is not an
act of infringement to submit an ANDA for approval to
market a drug for a use when neither the drug nor that
use is covered by an existing patent.”).
    In sum, the district court erred by finding that Aller-
gan showed literal infringement of claims 1–8 of the ’425
patent.
                             D
    Allergan argues on its cross-appeal that the district
court erred in finding that Sandoz’s proposed generic does
not infringe claim 4 of the ’149 patent and claim 1 of the
976 patent. Allergan again asserted only literal in-
fringement with respect to those claims. Both the claims
specifically recite 0.2% brimonidine. But the proposed
generic contains 0.2% brimonidine titrate, a distinct
pharmaceutical compound that reduces to 0.132%
brimonidine—indeed, Allergan’s expert confirmed so. J.A.
ALLERGAN SALES, LLC   v. SANDOZ, INC.                     9



2710–11; see also J.A. 117. As such, the district court did
not err by finding that Allergan failed to show literal
infringement of claim 4 of the ’149 patent and claim 1 of
the ’976 patent.
                              III
    We have considered remaining arguments and find
them unpersuasive. Accordingly, we affirm the district
court’s finding of no invalidity of the asserted claims and
non-infringement of the claims of the ’149 and ’976 pa-
tents, but reverse the finding of infringement of claim 1 of
the ’425 patent.
 AFFIRMED-IN-PART AND REVERSED-IN-PART
   No costs.
