       NOTE: This disposition is nonprecedential.

  United States Court of Appeals
      for the Federal Circuit
              __________________________

 WARNER CHILCOTT LABORATORIES IRELAND
                 LIMITED,
 WARNER CHILCOTT COMPANY, LLC, WARNER
           CHILCOTT (US), LLC,
  AND MAYNE PHARMA INTERNATIONAL PTY.
                    LTD.,
             Plaintiffs-Appellees,
                           v.
 MYLAN PHARMACEUTICALS INC. AND MYLAN
                  INC.,
           Defendants-Appellants.
              __________________________

                      2011-1611
              __________________________

    Appeal from the United States District Court for the
District of New Jersey in case no. 09-CV-2073, Judge
William J. Martini.
               _________________________

             Decided:   December 12, 2011
               _________________________

    DOMINICK A. CONDE, Fitzpatrick, Cella, Harper &
Scinto, of New York, New York argued for plaintiffs-
appellees. With him on the brief were DIEGO SCAMBIA;
WARNER CHILCOTT LABS     v. MYLAN PHARMA                2


and BRIAN L. KLOCK, of Washington, DC. Of counsel on
the brief was JONATHAN M.H. SHORT, McCarter & Eng-
lish, LLP, of Newark, New Jersey.

    LARRY L. SHATZER, Wilson Sonsini Goodrich & Rosati,
P.C., of Washington, DC, argued for defendants-
appellants. With him on the brief were Shaun R. Snader;
and Tung-On Kong, of San Francisco; and Jennifer Koh,
of San Diego, California.
               __________________________

 Before RADER, Chief Judge, DYK and O’MALLEY, Circuit
                       Judges.
O’MALLEY, Circuit Judge.
     This is a Hatch-Waxman Act case in which Mylan
Pharmaceuticals Inc. and Mylan Inc. (collectively, “My-
lan”) appeal the district court’s entry of a preliminary
injunction prohibiting Mylan from launching the generic
version of 150 mg Doryx, which is the branded name for
the doxycycline hyclate delayed-release tablets sold by
Plaintiffs-Appellees. Because the district court relied on
disputed facts in granting the preliminary injunction
without holding an evidentiary hearing, and failed to
make any findings as to Mylan’s invalidity defense, we
vacate the preliminary injunction and remand this action
for further proceedings.
                    I.    BACKGROUND
    Plaintiff-Appellee Mayne Pharma International Pty.
Ltd. (“Mayne”) is the holder of New Drug Application No.
50-795 relating to delayed release tablets containing 75
mg base, 100 mg base, and 150 mg base of doxycycline
hyclate. Mayne also owns U.S. Patent No. 6,958,161 (“the
’161 Patent”), entitled “Modified Release Coated Drug
Preparation,” which covers the branded drug Doryx.
3                   WARNER CHILCOTT LABS   v. MYLAN PHARMA


Mayne licenses the ’161 Patent to Plaintiffs-Appellees
Warner Chilcott 1 and has partnered with Warner Chilcott
to market Doryx in the United States.
    On December 5, 2008, Mylan filed an Abbreviated
New Drug Application (“ANDA”) to sell a generic version
of 150 mg Doryx. Mylan included with its ANDA a certi-
fication under 21 U.S.C. § 355(j)(2)(A)(vii)(IV) asserting
that the ’161 Patent is invalid, unenforceable, and/or will
not be infringed by the manufacture, use, or sale of My-
lan’s proposed generic drug. Following Mylan’s ANDA, on
May 1, 2009, Warner Chilcott filed an infringement suit
against Mylan in district court, triggering the thirty-
month statutory stay of approval of Mylan’s ANDA prod-
uct by the U.S. Food and Drug Administration (“FDA”).
The district court consolidated Warner Chilcott’s suit
against Mylan for discovery purposes with several other
suits Warner Chilcott filed against other companies that,
like Mylan, are seeking to sell generic versions of Doryx.
    The only claim at issue for purposes of this appeal is
claim 21 of the ’161 Patent, which recites:
    A tablet for oral administration, the tablet being a
    modified release preparation having one or more
    coated core elements, each core element compris-
    ing an active ingredient comprising an acid salt of
    doxycycline and having a modified release coating,
    wherein a stabilising coat is provided between
    each core element and its modified release coating
    so that, upon in vitro dissolution testing, the

    1    The following Warner Chilcott entities are named
plaintiffs in this lawsuit: Warner Chilcott Laboratories
Ireland Limited; Warner Chilcott Company, LLC; and
Warner Chilcott (US), LLC. For ease of reference, we
refer to all Plaintiffs-Appellees collectively as “Warner
Chilcott.”
WARNER CHILCOTT LABS   v. MYLAN PHARMA                    4


   amount of active ingredient released at any time
   on a post-storage dissolution profile is within 40
   percentage points of the amount of active ingredi-
   ent released at any time on a pre-storage dissolu-
   tion profile.
’161 Patent col. 14 ll.20-23 (emphasis added).
    In this case, Warner Chilcott’s infringement argument
turns on whether Mylan’s ANDA product has the claimed
“stabilizing coat.” On July 20, 2011, following the parties’
submissions and a hearing pursuant to Markman v.
Westview Instruments, Inc., 52 F.3d 967 (Fed. Cir. 1995)
(en banc), the district court construed the emphasized
language above, which includes “stabilizing coat,” to mean
“a layer of material(s) between each core element and its
modified release coating, which keeps the migration of
core materials to a minimum such that the interaction of
core materials with coating materials is reduced or pre-
vented.” Warner Chilcott Labs. Ireland v. Impax Labs.,
Inc., 2011 WL 2971155, at *7 (D.N.J. Jul. 20, 2011).
    On August 24, 2011, just over one month before the
end of the FDA’s thirty-month stay on September 27,
2011, Warner Chilcott filed a motion for a temporary
restraining order and preliminary injunction against
Mylan, seeking to prohibit Mylan from launching its
generic 150 mg product once it received final approval
from the FDA. 2 The parties briefed Warner Chilcott’s
motions and submitted witness declarations, including

   2     Mylan received tentative approval of its ANDA on
June 10, 2011 and expected final approval on or before
September 30, 2011. As of the date of this opinion, how-
ever, Mylan has not yet received final approval. At oral
argument before this court, Mylan asserted its belief that
the FDA was withholding final approval because of the
district court’s preliminary injunction, but Mylan did not
offer any support in the record for that assertion.
5                   WARNER CHILCOTT LABS   v. MYLAN PHARMA


declarations from their respective experts. The district
court heard arguments from counsel regarding both
motions on September 21, 2011. The court did not con-
duct an evidentiary hearing and did not hear live testi-
mony from any of the witnesses. The hearing lasted just
over an hour.
     The majority of the hearing focused on the parties’ re-
spective experts and various tests those experts had
performed to show the existence or non-existence of a
“stabilizing coat” in Mylan’s ANDA product. In other
words, the court’s primary focus was on the question of
whether Warner Chilcott was likely to succeed on the
merits of its infringement claim, a question which turned
on a battle of experts. Warner Chilcott’s expert relied on
one test to conclude that Mylan’s product met the “stabi-
lizing coat” limitation, while Mylan’s expert relied on five
different tests to reach the opposite conclusion. The
district court recognized that determining which tests to
credit was “one of the threshold inquiries,” and that there
existed “some serious factual disputes between the ex-
perts” on this issue. Joint Appendix (“J.A.”) A25; see also
J.A. 57 (“[T]here’s clearly factual disputes between the
two of you.”). The court also acknowledged that “this
would all be the subject of further testimony and exami-
nation and credibility,” J.A. 51, which the court would
consider at the full trial on the merits.
    After the court expressed its views on this issue, My-
lan’s counsel requested a one- or two-day evidentiary
hearing with live witness testimony, where the court
could hear from the battling experts. The court declined
to conduct a hearing, however, and indicated that it would
reserve these issues for a full trial. The court noted,
moreover, that it would not have time to conduct such a
trial until January 2012 because of an upcoming lengthy
criminal trial that would occupy the court’s schedule
WARNER CHILCOTT LABS    v. MYLAN PHARMA                      6


during the fall of 2011. See J.A. 54-55 (“I have a six- to
eight-week trial starting October 11th, a murder trial,
and that has to get priority . . . . So I have no time the rest
of this fall, certainly no time to do a preliminary injunc-
tion hearing, which I don’t think limited testimony is
going to be so helpful. I’d rather have the full trial.”).
     Ultimately, the district court ruled that Warner Chil-
cott had demonstrated that: (1) it was likely to succeed in
proving that Mylan’s product infringed the ’161 Patent;
(2) it would suffer irreparable harm absent an injunction;
and (3) that the balance of hardships favored Warner
Chilcott. On this basis, the court entered a preliminary
injunction pending resolution of the trial on the merits.
Notably, the district court did not address Mylan’s argu-
ments that the ’161 Patent is invalid because of anticipa-
tion or obviousness, though it did acknowledge that those
claims had been asserted.
    The day after the hearing, the district court issued a
two-page order granting Warner Chilcott’s motion and
preliminarily enjoining Mylan from selling generic 150 mg
Doryx “during the pendency of this injunction and until
the Court has resolved all issues of validity and infringe-
ment relating to the patents-in-suit.” Order Granting
Preliminary Injunction Against Defendants Mylan Phar-
maceuticals Inc. and Mylan Inc., Warner Chilcott Labs.
Ireland Ltd. v. Mylan Pharms., Inc., Case No. 09-cv-2073
(Sept. 22, 2011), ECF No. 53. The court also ordered
Warner Chilcott to post a bond in the amount of $36
million.
    After unsuccessfully requesting that the district court
stay its injunction pending appeal, Mylan filed a motion
to stay the preliminary injunction in this court and re-
quested expedited briefing on the merits of Mylan’s chal-
lenge to the district court’s preliminary injunction. This
7                    WARNER CHILCOTT LABS   v. MYLAN PHARMA


court ordered expedited briefing, scheduled oral argument
on the merits of Mylan’s appeal, and ultimately denied
Mylan’s motion to stay. The court heard argument on the
merits appeal on November 22, 2011.
                 II. STANDARD OF REVIEW
     This court applies regional circuit law, here that of
the Third Circuit, when reviewing a district court’s deci-
sion to grant a preliminary injunction. Abbott Labs. v.
Sandoz, Inc., 544 F.3d 1341, 1367 (Fed. Cir. 2008) (citing
Mikohn Gaming Corp. v. Acres Gaming, Inc., 165 F.3d
891, 894 (Fed. Cir. 1998)). We review the district court’s
decision for “an abuse of discretion, an error of law, or a
clear mistake in the consideration of proof.” Kos Pharms.,
Inc. v. Andrx Corp., 369 F.3d 700, 708 (3d Cir. 2004)
(quotation and citation omitted). “Thus, we exercise
plenary review over the district court’s conclusions of law
and its application of law to the facts, but review its
findings of fact for clear error, which occurs when we are
left with a definite and firm conviction that a mistake has
been committed.” Id. (quotation and citation omitted).
                      III. DISCUSSION
     A plaintiff seeking a preliminary injunction must es-
tablish that: (1) “he is likely to succeed on the merits”; (2)
“he is likely to suffer irreparable harm in the absence of
preliminary relief”; (3) “the balance of equities tips in his
favor”; and (4) “an injunction is in the public interest.”
Winter v. Natural Res. Def. Council, Inc., 555 U.S. 7, 20
(2008) (citations omitted). Such an injunction is “an
extraordinary remedy never awarded as of right.” Id.
(citation omitted). Where, as here, an accused infringer
has challenged the validity of a patent in response to a
motion for a preliminary injunction, this court has ad-
dressed the procedures district courts are to use to ana-
lyze the question of validity. See, e.g., Titan Tires Corp. v.
WARNER CHILCOTT LABS   v. MYLAN PHARMA                     8


Case New Holland, Inc., 566 F.3d 1372, 1378-79 (Fed. Cir.
2009). As it relates to the present appeal, we have ex-
plained that “the trial court first must weigh the evidence
both for and against validity that is available at this
preliminary stage in the proceedings.” Id. at 1379.
    In this case, the district court abused its discretion in
two ways. The court: (1) failed to hold an evidentiary
hearing despite acknowledging that the decision turned
on disputed factual issues; and (2) did not weigh the
evidence or make any findings as to Mylan’s invalidity
challenge. 3 As discussed below, these errors warrant
vacating the preliminary injunction.
         A. Failure to Hold Evidentiary Hearing
    In the Third Circuit, as in other circuits, “a district
court cannot issue a preliminary injunction that depends
upon the resolution of disputed issues of fact unless the
court first holds an evidentiary hearing.” Elliott v. Kie-
sewetter, 98 F.3d 47, 53 (3d Cir. 1996) (citing Prof’l Plan
Examiners of New Jersey, Inc. v. Lefante, 750 F.2d 282,
288 (3d Cir. 1984)); see also Ty, Inc. v. GMA Accessories,
Inc., 132 F.3d 1167, 1171 (7th Cir. 1997) (“If genuine
issues of material fact are created by the response to a
motion for a preliminary injunction, an evidentiary hear-

    3    While the trial court also did not address the pub-
lic interest, neither party presses that point on appeal or
argues that there are public interest factors that would
materially alter the analysis of the propriety of temporary
injunctive relief in this case. Thus, while it is generally
error to fail to address any of the four preliminary injunc-
tion factors, we do not rely on that error in resolving this
appeal. See McAulay v. U.S. Banknote Corp., 13
U.S.P.Q.2d 1990, 1991 (Fed. Cir. 1989) (unpublished)
(citing Pretty Punch Shoppettes, Inc. v. Hauk, 844 F.2d
782, 784-85 (Fed. Cir. 1988)); Texas Instruments, Inc. v.
Tessera, Inc., 231 F.3d 1325, 1329 (Fed. Cir. 2000).
9                   WARNER CHILCOTT LABS    v. MYLAN PHARMA


ing is indeed required.”). In such cases, “[t]he chief ques-
tion . . . is whether, in ordering the preliminary injunc-
tion, the district court relied upon any facts that were
properly disputed.” Williams v. Curtiss-Wright Corp., 681
F.2d 161, 163 (3d Cir. 1982).
    Here, it is clear that the district court relied on dis-
puted factual issues in granting Warner Chilcott’s motion
for a preliminary injunction. Indeed, the court expressly
identified those disputed issues when it explained that
there were “some serious factual disputes between the
experts” and “there’s clearly factual dispute between the
two of you.” J.A. 25, 57. Rather than resolving those
disputes through an evidentiary hearing, followed by
adequate factual findings, as Mylan requested, the court
put them aside for a later day. That runs afoul of the
Third Circuit case law cited above.
     This is also not a case like Elliott, where the Third
Circuit excused the district court’s failure to hold an
evidentiary hearing because the district court “impliedly
resolved” any factual issues in favor of the plaintiff. 98
F.3d at 54. In this case, the court expressly identified
that the dispute between the parties’ experts would
necessitate further testimony and cross examination, but
nonetheless granted a preliminary injunction on an
unsettled record. Sims v. Greene, 161 F.2d 87, 88 (3d Cir.
1947) (“The allegations of the pleadings and affidavits
filed in the cause are conflicting. Such conflicts must be
resolved by oral testimony since only by hearing the
witnesses and observing their demeanor on the stand can
the trier of fact determine the veracity of the allegations .
. . made by the respective parties.”). Although we recog-
nize and are not unsympathetic to the district court’s
scheduling demands and the difficulty in balancing a busy
criminal docket with pressing civil matters, the district
court’s chosen course is contrary to Third Circuit law, and
WARNER CHILCOTT LABS   v. MYLAN PHARMA                    10


its decision must be vacated.
            B. Lack of Findings as to Validity
    The district court also failed to make any findings as
to Mylan’s invalidity challenge, thus preventing this court
from engaging in any meaningful review of that issue. A
court “must find the facts specially and state its conclu-
sions of law separately.” Fed. R. Civ. P. 52(a)(1). “It is of
the highest importance to a proper review of the action of
a court in granting or refusing a preliminary injunction
that there should be fair compliance with Rule 52(a) of
the Rules of Civil Procedure.” Mayo v. Lakeland High-
lands Canning Co., 309 U.S. 310, 316 (1940); Kos
Pharms., 369 F.3d at 712 n.10 (quoting Mayo and explain-
ing that a district court’s failure to explain each of the
likelihood of confusion factors in a trademark infringe-
ment analysis “runs afoul of Rule 52(a)”); see also Nutri-
tion 21 v. United States, 930 F.2d 867, 869 (Fed. Cir.
1991) (“Sufficient factual findings on the material issues
are necessary to allow this court to have a basis for mean-
ingful review.”). Absent appropriate findings, the normal
course is to vacate the district court’s decision and re-
mand the matter for a proper analysis. See Sabinsa Corp.
v. Creative Compounds, LLC, 609 F.3d 175, 183 (3d Cir.
2010) (“Typically, when a district court fails to adequately
support its findings, we merely remand for a re-weighing
of the applicable factors.”); Pretty Punch Shoppettes, Inc.
v. Hauk, 844 F.2d 782, 785 (Fed. Cir. 1988) (same).
    The district court in this case made no more than
passing reference to Mylan’s invalidity challenge, and did
not make any express findings as to validity of the ’161
Patent. Although there is no precise formula district
courts must use rendering their findings under Rule
52(a), an utter failure to make any findings contravenes
that rule. In addition to violating Rule 52(a), these omis-
11                  WARNER CHILCOTT LABS    v. MYLAN PHARMA


sions are also contrary to our case law, which requires
district courts to consider both the accused infringer’s
validity defense and the patentee’s arguments in support
of its patent. See Titan Tire, 566 F.3d at 1379 (“[T]he
trial court first must weigh the evidence both for and
against validity that is available at this preliminary stage
in the proceedings.”). Accordingly, we remand the matter
for the district court to make appropriate findings consis-
tent with these authorities.4
                     IV. CONCLUSION
    Although the district court’s entry of the preliminary
injunction in this case is contrary to controlling authority,
we are mindful of the court’s demanding schedule and
desire to avoid duplicating its efforts with a soon-to-be-
scheduled bench trial in this case. If doing so serves
judicial efficiency, the district court may consider entering
a temporary restraining order after this court’s mandate
issues, then consolidating the preliminary injunction
hearing with the bench trial on the merits, assuming that
can occur within the timeframes mandated by the Federal
Rules of Civil Procedure. See Salinger v. Colting, 607
F.3d 68, 84 (2d Cir. 2010). With that in mind, we remand
this matter for proceedings consistent with this order.
              VACATED AND REMANDED




     4   While Mylan does so, we take no issue with the
adequacy of the trial court’s findings on irreparable harm
and the balance of hardships, and do not order the court
to revisit those questions, unless it chooses to do so.
