Abbott Laboratories v. Andrx Pharmaceuticals, Inc.

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United States Court of Appeals for the Federal Circuit

06-1101

ABBOTT LABORATORIES,

Plaintiff-Appellee,

v.

ANDRX PHARMACEUTICALS, INC.,

Defendant-Appellant,

and

ROXANE LABORATORIES, INC. and TEVA PHARMACEUTICALS USA, INC.,

Defendants.

Jeffrey I. Weinberger, Munger, Tolles & Olson, LLP, of Los Angeles, California,
argued for plaintiff-appellee. With him on the brief was Ted G. Dane. Of Counsel on the
brief were Jason Rantanen and Genevieve A. Cox, of San Francisco, California.

Eric D. Isicoff, Isicoff, Ragatz & Koenigsberg, of Miami, Florida, argued for
defendant-appellant. With him on the brief was Teresa Ragatz. Of counsel on the brief
were Alan B. Clement, Martin P. Endres, and Katharine G. Loving, Hedman & Costigan,
P.C., of New York, New York; and Steven H. Sklar, Leydig, Voit & Mayer, Ltd., of
Chicago, Illinois.

Appealed from: United States District Court for the Northern District of Illinois

Judge David H. Coar
 United States Court of Appeals for the Federal Circuit

06-1101

ABBOTT LABORATORIES,

Plaintiff-Appellee,

v.

ANDRX PHARMACEUTICALS, INC.,

Defendant-Appellant,

and

ROXANE LABORATORIES, INC. and TEVA PHARMACEUTICALS USA, INC.,

Defendants.

__________________________

DECIDED: January 5, 2007
__________________________

Before MICHEL, Chief Judge, PROST, Circuit Judge, ELLIS,∗ District Judge.

PROST, Circuit Judge.

Abbott Laboratories (“Abbott”) brought suit against Andrx Pharmaceuticals, Inc.

(“Andrx”) alleging infringement of its patents relating to extended release formulations of

clarithromycin. Abbott moved for a preliminary injunction based on Andrx’s alleged

infringement of claims 1, 4, and 6 of U.S. Patent No. 6,010,718 (“’718 patent”); claim 2

∗
Hon. T.S. Ellis, III, from the United States District Court for the Eastern
District of Virginia, sitting by designation.
of U.S. Patent No. 6,551,616 (“’616 patent”); and claims 8 and 16 of U.S. Patent No.

6,872,407 (“’407 patent”). The district court granted the injunction with respect to all the

asserted claims. The court concluded that Abbott had shown a likelihood of proving

infringement of the ’616 and ’718 patents under the doctrine of equivalents and

infringement of the ’407 patent under literal infringement, and that Andrx had not shown

a likelihood of proving that any of the patents are invalid. Ranbaxy Labs. Ltd. v. Abbott

Labs., Abbott Labs. v. Andrx Pharms. Inc., Nos. 04 C 8078, 05 C 1490 (N.D. Ill. Nov.

10, 2005) (“Ranbaxy-Andrx”).1 Andrx appeals, arguing (1) that Abbott is collaterally

estopped from asserting certain claims in the three patents because of findings of

invalidity and unenforceability of the patents in proceedings against other defendants;

and (2) that the district court erred in finding that Abbott is likely to succeed in proving

infringement with respect to any of the asserted claims of the three patents. Because

we find that collateral estoppel does not apply and the district court did not abuse its

discretion in finding Abbott is likely to succeed on the merits, we affirm.

I. BACKGROUND

Abbott Laboratories accused several manufacturers of infringement of its patents

related to its extended release clarithromycin product, Biaxin XL®. Three such cases

are relevant to this appeal—Abbott’s cases against Teva Pharmaceuticals (“Teva”),

Ranbaxy, and Andrx, the defendant in the instant appeal. Each of these defendants

1
The district court issued a single Memorandum Opinion and Order
resolving two separate motions for preliminary injunction filed against Andrx, and
Ranbaxy Laboratories, Ltd. and Ranbaxy Pharmaceuticals, Inc. (collectively “Ranbaxy”).
The motion against Ranbaxy was filed in case number 04 C 8078 and is discussed at
pages 5-36 of the Memorandum Opinion, the motion against Andrx was filed in case
number 05 C 1490 and is discussed at pages 37-57 of the same Memorandum Opinion.

06-1101 2
sought approval to manufacture and market a generic version of Biaxin XL® and

accordingly filed abbreviated new drug applications (“ANDAs”) with the Food and Drug

Administration (“FDA”). Each of the ANDAs was approved. Abbott’s claims of

infringement against these three defendants are all being heard before a single district

judge in the Northern District of Illinois. Abbott filed motions for preliminary injunctions

against each of the three generic drug manufacturers seeking to enjoin their production

and marketing of extended release clarithromycin. The instant appeal is from the

district court’s grant of a preliminary injunction against Andrx based on the court’s

conclusion that Abbott is likely to prove infringement of the ’718, ’616, and ’407 patents,

and that Andrx is not likely to succeed in proving its defenses.

The ’718 patent describes and claims extended release formulations comprising

erythromycin derivatives combined with a pharmaceutically acceptable polymer. The

extended release formulations enable patients to take one pill per day rather than twice,

as had been required with the immediate release formulation. The ’616 is a

continuation-in-part of the ’718 patent and claims a method of reducing adverse

gastrointestinal side effects, relative to immediate release formulations of erythromycin-

derived drug formulations, by using extended release formulations. The ’407 patent is a

continuation patent of the ’616 patent and claims erythromycin derivative formulations

with certain specified pharmacokinetic properties. The claims at issue in this appeal are

solely those on which Abbott based its motion for a preliminary injunction against Andrx:

claims 1, 4, and 6 of the ’718 patent, claim 2 of the ’616 patent, and claims 8 and 16 of

the ’407 patent.

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 Certain holdings in Abbott’s cases against Ranbaxy and Teva are relevant to our

analysis in this appeal. First, in the district court’s order resolving Abbott’s motion for a

preliminary injunction against Ranbaxy, the court held that Ranbaxy had shown that it

was likely to succeed in proving that the ’616 and ’407 patents are unenforceable due to

inequitable conduct. Ranbaxy-Andrx, slip op. at 7. Second, the district court held, in an

order resolving Abbott’s preliminary injunction motion against Teva, that Teva had

raised a substantial question that claim 2 of the ’616 patent was obvious under 35

U.S.C. § 103, and therefore Teva was likely to succeed in proving invalidity of that

claim. Abbott Labs. v. Andrx Pharms., Inc., No. 05 C 1490, slip op. at 22 (N.D. Ill. June

8, 2005) (“Teva I”). Finally, on appeal from Teva I, this court held that Teva had also

raised substantial questions as to the validity of claims 2, 4, and 6 of the ’718 patent.

Abbott Labs. v. Andrx Pharms., Inc., 452 F.3d 1331, 1348 (Fed. Cir. 2006) (“Teva II”).

Turning to the history of the instant appeal, Abbott’s complaint against Andrx

sought, inter alia, declaratory judgment of infringement of the ’407, ’616, and ’718

patents. On May 18, 2005, Abbott moved to preliminarily enjoin Andrx from marketing

its generic version of extended release clarithromycin (“the Andrx product”). In

opposition to Abbott’s motion, Andrx contended that it does not infringe any of the

asserted patents, either literally or under the doctrine of equivalents. In addition, Andrx

defended against Abbott’s motion by arguing that Abbott’s patents are invalid for

indefiniteness under 35 U.S.C. § 112, ¶ 2 (all three patents), invalid for anticipation

under 35 U.S.C. § 102(b) (the ’718 and ’616 patents), and invalid for obviousness under

35 U.S.C. § 103. Ranbaxy-Andrx, slip op. at 53-58.

06-1101 4
 The district court held a hearing on September 21, 2005 on Abbott’s preliminary

injunction motion against Andrx and issued a single order resolving both Abbott’s motion

against Andrx and Abbott’s motion against Ranbaxy. With respect to Andrx, the court

held that Abbott succeeded in proving a likelihood of success on its claims that Andrx

infringes claims 1, 4, and 6 of the ’718 patent under the doctrine of equivalents; induces

and contributes to infringement under the doctrine of equivalents of claim 2 of the ’616

patent; and literally infringes claims 8 and 16 of the ’407 patent. Ranbaxy-Andrx, slip

op. at 39-53. As to Andrx’s invalidity defenses, the district court held that Andrx failed to

meet its burden of raising a substantial question of invalidity as to any of the three

asserted patents. Id., slip op. at 53-58. Accordingly, the court granted Abbott’s motion

for a preliminary injunction based on the ’718, ’616, and ’407 patents.

Andrx appeals the district court’s preliminary injunction order enjoining it from

manufacturing and marketing its extended release clarythromycin product. Because

this court’s opinion in Teva II issued after the filing of briefs in Andrx’s appeal, the

parties’ briefs did not address the estoppel effect, if any, of that opinion on the instant

appeal. We therefore granted Abbott’s motion, made after oral argument, requesting

leave to provide supplemental briefing, requesting the parties to brief the court

regarding the extent to which Teva II has a collateral estoppel or other binding effect on

the instant appeal. Accordingly, both Abbott and Andrx filed supplemental briefs on this

issue.2

We have jurisdiction over this appeal pursuant to 28 U.S.C. § 1292(c)(1).

2
Abbott filed, along with its supplemental brief, a motion to file a
supplemental appendix. The motion is denied.

06-1101 5
 II. DISCUSSION

On appeal, Andrx presents two distinct arguments as to why the district court

erred in granting a preliminary injunction. First, Andrx asserts that Abbott is collaterally

estopped from seeking a preliminary injunction based on holdings in the preliminary

injunction proceedings against Teva and Ranbaxy that all of the asserted claims are

invalid or unenforceable. Second, Andrx argues that the district court erred in finding

that it could infringe any of the asserted patents. Specifically, Andrx contends that it

cannot infringe the ’718 and ’616 patents under the doctrine of equivalents because it

does not contain the “pharmaceutically acceptable polymer” required by all the asserted

claims. Andrx also contends that the district court erred in concluding that Abbott

showed a likelihood of prevailing in asserting infringement of the ’407 patent because

the court specifically found that the Andrx product did not satisfy one limitation of the

asserted claims.

We address each of Andrx’s arguments in turn below, reviewing the district

court’s decision to grant a motion for preliminary injunction for an abuse of discretion.

Novo Nordisk of N. Am., Inc. v. Genentech, Inc., 77 F.3d 1364, 1367 (Fed. Cir. 1996).

“To overturn the grant of a preliminary injunction, we must find that the district court

made a clear error of judgment in weighing the relevant factors or based its exercise of

discretion on an error of law or on clearly erroneous factual findings.” Pfizer, Inc. v.

Teva Pharms., USA, Inc., 429 F.3d 1364, 1372 (Fed. Cir. 2005).

The four factors relevant to the district court’s decision to grant or deny a

preliminary injunction are “(1) the likelihood of the patentee’s success on the merits;

(2) irreparable harm if the injunction is not granted; (3) the balance of hardships

06-1101 6
between the parties; and (4) the public interest.” Oakley, Inc. v. Sunglass Hut Int’l, 316

F.3d 1331, 1338-39 (Fed. Cir. 2003) (citing Amazon.com, Inc. v. Barnesandnoble.com,

Inc., 239 F.3d 1343, 1350 (Fed. Cir. 2001)). In order to establish the first preliminary

injunction factor, Abbott must show that it will likely prove that Andrx infringes at least

one valid and enforceable patent claim. Pfizer, 429 F.3d at 1372. Likewise, in order to

defeat the injunction based on invalidity or unenforceability defenses, Andrx, as the

party bearing the burden of proof on the issue at trial, must establish a substantial

question of invalidity or unenforceability, i.e., that it is likely to succeed in proving

invalidity or unenforceability of the asserted patents. See Gonzales v. O Centro Espirita

Beneficente Uniao Do Vegetal, 126 S.Ct. 1211, 1219-20 (2006) (“[T]he burdens at the

preliminary injunction stage track the burdens at trial.”); Ashcroft v. Am. Civil Liberties

Union, 542 U.S. 656, 666 (2004).

A. Collateral Estoppel

Andrx’s contentions regarding collateral estoppel involve the district court

decisions in preliminary injunction proceedings regarding defendants Ranbaxy and Teva

and this court’s decision in Teva’s appeal from those proceedings.

When Abbott moved for preliminary injunctions against Teva, Ranbaxy, and

Andrx, the district court accepted separate arguments and held separate hearings for

each defendant. Abbott presented different infringement contentions specific to the

accused product of each defendant and each defendant presented its own and different

defenses. In particular, Teva argued that claims of the ’616 and ’718 patents were

invalid based on different prior art than that raised by Andrx. The district court did not

find Teva’s invalidity defenses regarding claims 2, 4, and 6 of the ’718 patent

06-1101 7
persuasive and granted an injunction against Teva based on those claims. Teva I, slip

op. at 9-20. The court found that Teva had raised a substantial question of validity as to

claim 2 of the ’616 patent and denied a preliminary injunction based on that claim. Id.,

slip op. at 20-22. In the preliminary injunction proceedings against Andrx, however, the

court granted the requested injunction based partly on claim 2 of the ’616 patent, finding

that Andrx had not raised a substantial question of validity based on its different validity

arguments regarding that claim. Ranbaxy-Andrx, slip op. at 53-58, 62. Andrx argues

that, having found claim 2 of the ’616 patent invalid against Teva, the district court erred

in permitting Abbott to enforce the claim against Andrx.

Defendant Ranbaxy also raised different defenses than Andrx. Ranbaxy

defended against a preliminary injunction by arguing, inter alia, that Abbott’s patents

were unenforceable due to Abbott’s inequitable conduct before the United States Patent

and Trademark Office (“PTO”). Id., slip op. at 7. Andrx did not expressly raise

unenforceability defenses to the district court for purposes of fending off a preliminary

injunction.3 The district court issued a single order deciding the preliminary injunction

issues for both Ranbaxy and Andrx. The court found that Ranbaxy showed a likelihood

of success in proving that the ’616 and ’407 patents were unenforceable due to

inequitable conduct and therefore denied a preliminary injunction against Ranbaxy

based on those patents. Id., slip op. at 18. In the order, the court also granted a

3
Andrx asserts that it raised unenforceability due to inequitable conduct as
a defense, pointing to a single statement made at the district court’s preliminary
injunction hearing. The district court opinion only noted that Andrx raised invalidity
defenses, not any unenforceability defenses. Ranbaxy-Andrx, slip op. at 53. Therefore,
we will not consider Andrx as having asserted unenforceability defenses in opposition to
Abbott’s motion for preliminary injunction.

06-1101 8
preliminary injunction against Andrx based on the same two patents. Id., slip op. at 62.

Andrx argues that the district court erred by failing to preclude Abbott from enforcing

these patents against Andrx after finding them unenforceable against Ranbaxy. The

district court’s order did not address this estoppel issue.

At the time the district court issued its order resolving the preliminary injunction

motions against Ranbaxy and Andrx, the preliminary injunction findings in Teva I were

on appeal to this court. When Andrx and Abbott briefed the instant appeal, this court’s

Teva II decision had not issued. In Teva II, this court affirmed the district court’s finding

that Teva had shown a substantial question of validity as to claim 2 of the ’616 patent.

452 F.3d at 1347. This court also reversed the district court, finding that Teva had also

shown a likelihood of proving the invalidity of claims 2, 4, and 6 of the ’718 patent. Id. at

1348. In its appeal, Andrx has extended the scope of its collateral estoppel arguments

to encompass this court’s decision in Teva II, i.e., Andrx argues that Abbott is also

precluded from asserting claim 2 of the ’616 patent and claims 2, 4, and 6 of the ’718

patents because of the finding in Teva II that Teva showed there was a substantial

question as to those claims’ validity.

On appeal, Andrx argues that the Supreme Court’s decision in Blonder-Tongue

Laboratories, Inc. v. University of Illinois Foundation, 402 U.S. 313 (1971), requires that

Abbott cannot assert patents against one party which have been found to be invalid or

unenforceable against another party. In Blonder-Tongue, the Supreme Court permitted

accused infringers to plead collateral estoppel, also known as issue preclusion, when

facing an infringement claim on a patent already declared invalid in a proceeding

against another defendant. Id. at 350. Andrx primarily argues on appeal that Blonder-

06-1101 9
Tongue renders the district court’s decision granting preliminary injunction erroneous as

a matter of law—i.e., after decisions in Ranbaxy-Andrx, Teva I, and Teva II finding that

those defendants had shown a likelihood of proving invalidity or unenforceability of

Abbott’s patents, Abbott should not have been permitted to continue to assert the

patents in preliminary injunction proceedings against Andrx.

In response, Abbott argues that the courts’ findings in the preliminary injunction

proceedings against Teva and Ranbaxy should not be accorded preclusive effect and

that Blonder-Tongue does not compel the application of findings in the other cases to

Abbott’s case against Andrx.

Whether collateral estoppel applies to prevent Abbott from attempting to

preliminarily enjoin Andrx based on decisions in preliminary injunction proceedings

against other defendants is a procedural issue not unique to patent law. We therefore

apply the law of the regional circuit, here the Seventh Circuit.4 Dana v. E.S. Originals,

342 F.3d 1320, 1323 (Fed. Cir. 2003). We first address the parameters for applying

collateral estoppel addressed by the Supreme Court in Blonder-Tongue, followed by an

4
Abbott asserts that the question of whether to extend Blonder-Tongue to
the preliminary injunction context is a question unique to patent law and should be
governed by the law of this court, citing Pharmacia & Upjohn Co. v. Mylan
Pharmaceuticals, Inc., 170 F.3d 1373, 1381 n.4 (Fed. Cir. 1999). We disagree. The
very footnote cited by Abbott from Pharmacia supports application of Seventh Circuit
law in this case:
Application of Blonder-Tongue, being an issue of patent law, is a matter
within our exclusive jurisdiction and is hence subject to this court’s law.
However, because the application of general collateral estoppel principles,
such as finality of judgment, is not a matter within the exclusive jurisdiction
of this court, we must apply the law of the circuit in which the district court
here sits . . . .
170 F.3d at 1381 n.4 (emphasis added).

06-1101 10
analysis of the application of Blonder-Tongue’s collateral estoppel principles in the

Seventh Circuit.

In Blonder-Tongue, the Supreme Court discussed the importance of a final

determination on the merits to application of collateral estoppel. The decision was

limited to the issue of “permitting a patent holder to sue on his patent after it has once

been held invalid following opportunity for full and fair trial.” Blonder-Tongue, 402 U.S.

at 330 (emphasis added). The Supreme Court emphasized

we should keep firmly in mind that we are considering the situation where
the patentee was plaintiff in the prior suit and chose to litigate at that time
and place. Presumably he was prepared to litigate and to litigate to the
finish against the defendant there involved. Patent litigation
characteristically proceeds with some deliberation and, with the avenues
for discovery available under the present rules of procedure, there is no
reason to suppose that plaintiff patentees would face either surprise or
unusual difficulties in getting all relevant and probative evidence before the
court in the first litigation.

Id. at 332. Blonder-Tongue held that, in such situations, a defendant could plead

estoppel if it “identifies the issue in suit as the identical question finally decided against

the patentee in previous litigation.” Id. at 333. Once this showing has been made, the

patentee must be permitted to demonstrate that he did not have a “fair opportunity

procedurally, substantively and evidentially to pursue his claim the first time.” Id.

“Determining whether a patentee has had a full and fair chance to litigate the validity of

his patent in an earlier case is of necessity not a simple matter.” Id. Relevant factors

include which party had the choice of forum; whether the patentee had an incentive to

fully litigate in the prior litigation; and whether the patentee was deprived of crucial

evidence of witnesses in the first litigation through no fault of its own. Id.

06-1101 11
 In sum, Blonder-Tongue permitted the use of defensive collateral estoppel when

the accused infringer shows 1) that a patent was found invalid in a prior case that had

proceeded through final judgment and in which all procedural opportunities were

available to the patentee; 2) that the issues litigated were identical; and 3) that the party

against whom estoppel is applied had a full and fair opportunity to litigate. Abbott

argues that none of the Blonder-Tongue requirements for the application of collateral

estoppel are present in this case. According to Abbott, the Teva I, Teva II, and

Ranbaxy-Andrx decisions were not final judgments for purposes of estoppel; the issues

litigated in the current and prior proceedings were not identical because in each

proceeding the issue was whether the particular defendant had shown a likelihood of

succeeding based on its own asserted defenses; and it did not have a full and fair

opportunity to litigate the issue of invalidity in those proceedings.

With respect to the final judgment issue, Abbott argues that the Teva I, Teva II,

and Ranbaxy-Andrx decisions were not final judgments for purposes of estoppel

because they resulted from preliminary injunction proceedings in which either the district

court or this court found only that the defendants had shown a likelihood of proving

invalidity or unenforceability. Abbott argues these findings were based on a limited

record and limited opportunities for collecting or presenting evidence, and were

expressly preliminary rather than final findings on these issues. In response, Andrx

agrees that Blonder-Tongue addressed the case of a final judgment on the merits and

therefore is not directly applicable to a preliminary injunction determination. Andrx

argues, however, that Blonder-Tongue should be extended to estop Abbott from

seeking a preliminary injunction based on patents that have been found to be

06-1101 12
preliminarily unenforceable or invalid against other defendants. Andrx also contends

that the preliminary injunction holdings of invalidity and unenforceability in Teva I,

Teva II, and Ranbaxy-Andrx are “final” in the limited sense of having resolved the issue

of whether substantial questions of invalidity or unenforceability exist.

To determine whether findings made during preliminary injunction proceedings

may invoke collateral estoppel under Blonder-Tongue we look to the law of the Seventh

Circuit. That circuit has clearly held that in “certain rare instances,” a finding need not

be part of a final judgment on the merits in order to be preclusive. A.J. Canfield v. Vess

Beverages, 859 F.2d 36, 38 (7th Cir. 1988) (“Canfield”); see also Miller Brewing v. Jos.

Schlitz Brewing Co., 605 F.2d 990, 996 (7th Cir. 1979). 5

In Miller, Miller Brewing Company sued a competitor based on the trademark

“Lite.” In a prior case, the Seventh Circuit had upheld a district court’s denial of a

preliminary injunction based on the finding that the same asserted trademark was

invalid as generic. Miller, 605 F.2d at 991. In the second case, Miller had sued another

competitor, Schlitz, based on the same trademark. The district court found that the prior

finding of invalidity in the preliminary injunction context collaterally estopped Miller from

asserting the mark against Schlitz. On appeal, the Seventh Circuit considered whether

the prior determination was a final judgment for purposes of issue preclusion, as

required by Blonder-Tongue. Id. at 995-96.

On the question of whether the prior preliminary invalidity finding constituted a

final judgment, the court expressly held that a judgment need not be final in the sense of

5
This court has likewise held that a holding need not be a part of a final
judgment in order to be sufficiently final to invoke issue preclusion. Dana, 342 F.3d at
1323-25.

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28 U.S.C. § 1291. Id. at 996. Rather, “‘[f]inality’ in the context here relevant may mean

little more than that the litigation of a particular issue has reached such a stage that a

court sees no really good reason for permitting it to be litigated again.” Id. The decision

should be “sufficiently firm to be accorded conclusive effect.” Factors to consider in

determining whether a decision was adequately deliberated and firm include whether

the parties were fully heard, the court supported its decision with a reasoned opinion,

and the decision was subject to appeal. Id. But preclusion should be refused, the court

held, if the decision was “avowedly tentative.” Id. In Miller, the court held that the

generic status of the “Lite” mark had been so thoroughly litigated in the first preliminary

injunction proceeding that, as to that issue, there was a sufficient final judgment. Id.

Subsequent to Miller, the Seventh Circuit had occasion to clarify when a

preliminary injunction is a final judgment for purposes of issue preclusion. In Canfield,

the court discussed the preclusive effect of several holdings made in prior proceedings

on the issue of whether Canfield’s trademark “chocolate fudge” was generic for use with

diet sodas. In a first proceeding, a court had granted Canfield a preliminary injunction

against defendant Vess after a preliminary finding that the asserted mark was not

generic. Canfield, 859 F.2d at 37 (citing A.J. Canfield Co. v. Vess Beverages, Inc., 612

F.Supp. 1081 (N.D. Ill. 1985) (“Vess I”)). The Seventh Circuit had affirmed the

preliminary injunction. Id. (citing A.J. Canfield Co. v. Vess Beverages, Inc., 796 F.2d

903 (7th Cir. 1986) (“Vess II”)).

In another court, Canfield sought a preliminary injunction against defendant

Yoo-Hoo based on the same mark. The court in those proceedings found the

trademark generic and denied a preliminary injunction. Id. at 38 (citing Yoo-Hoo

06-1101 14
Chocolate Beverage Corp. v. A.J. Canfield Co., No. 85-3701, 1986 WL 9720, at *1

(D.N.J. Apr. 1, 1986)). Because the district court considered extensive evidence on the

issue during the preliminary injunction proceeding, it determined that Canfield “will not

and cannot succeed on the merits based upon the undisputed facts submitted.”

Yoo-Hoo, 1986 WL 9720 at *18. The court did give Canfield additional time, however,

to come forward with additional evidence that it did not present at the preliminary

injunction hearing on why its mark for “chocolate fudge” should not be found generic.

Canfield, 796 F.2d at 38. When Canfield failed to do so, the court entered a final

judgment in favor of Yoo-Hoo. Id.

In a third proceeding, Canfield sued and sought preliminary relief against another

defendant, Honickman, for use of the same “chocolate fudge” mark. There, the court

held that the term was generic for purposes of granting a preliminary injunction. Id. at

38 (citing A.J. Canfield v. Honickman, 808 F.2d 291 (3d Cir. 1986)).

Vess, the defendant against whom a preliminary injunction had been entered in

Vess I returned to court for vacatur of the injunction against it based on the holdings in

Honickman and Yoo-Hoo that the asserted mark was generic. Canfield, 859 F.2d at 37.

Canfield countered by arguing that the earlier findings in Vess I and Vess II that the

mark was not generic precluded application of the later-decided Honickman and

Yoo-Hoo holdings that the mark was generic. The Canfield court discussed when it is

appropriate to give preclusive effect to holdings made during preliminary injunction

proceedings.

In general, rulings in connection with grants or denials of preliminary relief
will not be given preclusive effect. Such rulings are often made on an
incomplete record and are inherently tentative in nature. Usually, the

06-1101 15
 grant or denial of relief is based not on a conclusive determination, but on
an estimate of the likelihood of success.

Canfield, 859 F.2d at 38 (citations omitted). In “certain rare circumstances,” however,

the court held that decisions granting or denying preliminary injunctions may be

sufficiently final to be given preclusive effect. Id. The exception to the general rule

permits decisions regarding preliminary relief to accord preclusive effect if the decisions

are necessarily based upon a determination that constitutes an “insuperable obstacle”

to the plaintiff’s success on the merits. Id. (citing Miller, 605 F.2d at 995). Such an

insuperable obstacle exists when a prior decision made in connection with a preliminary

injunction proceeding “clearly intended to firmly and finally resolve the issue,” rather

than “estimate the likelihood of success” of proving that issue. Id.; see also Teamsters

Local 705 v. Apex Auto. Warehouse, Inc., No. 90 C 6768, 1991 U.S. Dist. LEXIS 9471

(N.D. Ill. July 8, 1991) (citing Canfield, 859 F.2d at 38) (“When the prior injunction was

based upon the same issue the party seeks to foreclose, and the court in the earlier

decision conclusively determined that issue, then that situation falls within the

insuperable obstacle test.”)

The Canfield court thus had to determine whether each prior case resolved the

issue of whether “chocolate fudge” is generic in a way that intended to firmly and finally

resolve the issue. The court found that in both the Yoo-Hoo case and the Honickman

case, the district court opinions did reach final resolutions on that issue. The Yoo-Hoo

court had given Canfield the opportunity to present further evidence after its preliminary

finding that the mark was generic, and when Canfield did not, entered a final judgment

in Yoo-Hoo’s favor. Such a resolution was “clearly a decision on the merits for

purposes of collateral estoppel.” Id. at 38. The Honickman court had found the term

06-1101 16
generic only for purposes of a preliminary injunction. The opinion, however, showed

that the deciding judge “clearly intended to firmly and finally resolve the issue.” Id.

Therefore, it too was afforded preclusive effect.

The district court’s holding in Vess I, on the other hand, was not considered

sufficiently firm to be accorded preclusive effect. The district court judge in Vess I had

made no explicit finding as to whether the asserted mark was generic. Id. at 38-39.

Also, while the judge had raised the issue, he had not finally resolved it. Id. at 39. The

Canfield court held, therefore, that “any discussion of genericness in Vess I was in

terms of probabilities, not certainties, and the brief mention of the issue was not full

litigation and decision on the merits for purposes of issue preclusion.” Id. at 39.

Applying the principles of Canfield and Miller to the instant appeal, we conclude

that the determinations made in proceedings against defendants Teva and Ranbaxy

were not “full litigation and decision on the merits for purposes of issue preclusion.”

Andrx argues that there has been a final resolution of the limited issue of whether there

is a substantial question of invalidity of Abbott’s patents, but Seventh Circuit law does

not support this view. A determination that there is merely a likelihood of proving

invalidity is a determination made solely in terms of “probabilities, not certainties” and is

therefore not “full litigation and decision on the merits for purposes of issue preclusion.”

Id.

In both the Teva and Ranbaxy cases, the district court judge did not intend to

“firmly and finally resolve the issue” for which preclusion is asserted, the validity or

enforceability of the Abbott patents, in its preliminary injunction proceedings. As with

the opinion in Vess I, the Ranbaxy-Andrx opinion makes conclusions regarding the

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issue solely in terms of “probabilities, not certainties.” For example, the court’s

unenforceability finding with respect to Ranbaxy explicitly “preliminarily finds both the

’616 and the ’407 patents” unenforceable due to inequitable conduct. Ranbaxy-Andrx,

slip op. at 18-19 (emphasis added). Similarly, the invalidity findings with respect to

defendant Teva by both the district court and this court were solely that Teva showed a

“likelihood” of success in proving invalidity and were not conclusive findings. Teva II,

452 F.3d at 1348; Teva I, slip op. at 4. Contrary to the requirement of Miller, the Teva II

panel’s decision on invalidity was “avowedly tentative.” Teva II, 452 F.3d at 1337

(“[O]ur decision today in no way resolves the ultimate question of invalidity.” (emphasis

added)). Under Seventh Circuit precedent, we do not find this case, therefore, to

present the rare circumstance in which a determination made during a preliminary

injunction is sufficiently final to be accorded preclusive effect. Andrx’s arguments

seeking to collaterally estop Abbott from preliminarily enforcing its patents against Andrx

are accordingly rejected.

In light of this conclusion with respect to final judgments, we do not reach the

parties’ arguments regarding whether the issues litigated in the prior and present

proceedings are identical, or whether Abbott had a full and fair opportunity to litigate in

the prior proceedings. The collateral estoppel effect of Teva I, Teva II, and Ranbaxy-

Andrx was the only appealed basis for reversing the district court’s finding that the three

Abbott patents are preliminarily valid and enforceable as to Andrx. Accordingly, we

affirm the district court’s judgment in that regard.

B. Infringement

Andrx also challenges the district court’s finding that Abbott showed a likelihood

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of proving infringement of its asserted claims by Andrx. Irrespective of the conclusion

above regarding whether Abbott is estopped from relitigating the validity and

unenforceability of certain claims in its patents, we must still reach Andrx’s infringement

arguments as to claim 1 of the ’718 patent because it was not at issue in the

proceedings against the other defendants. Cf. Bourns, Inc. v. United States, 537 F.2d

486 (Ct. Cl. 1976) (holding that if the obviousness inquiry as to unadjudicated claims

present identical issues to those already adjudicated in a prior suit in which other claims

were found invalid, the patentee may be estopped from asserting the unadjudicated

claims). However, because of the holding that collateral estoppel does not apply here,

the arguments regarding claims 4 and 6 of the ’718 patent, claim 2 of the ’616 patent,

and claims 8 and 16 of the ’407 patent still require our review.

Andrx makes two arguments as to why it cannot infringe Abbott’s asserted claims

in any of the three patents. First, Andrx argues that it cannot infringe the ’718 and ’616

patents because its product does not satisfy the “pharmaceutically acceptable polymer”

limitation in the patents either literally or under the doctrine of equivalents. Second,

Andrx argues that the district court erred in finding that Abbott showed a likelihood of

proving infringement of the ’407 patent because the district court explicitly found that

Andrx’s product did not meet one of the pharmacokinetic property requirements recited

in the claims.

Turning to the first of these arguments, Andrx asserts that the district court erred

in granting a preliminary injunction based on the ’718 and ’616 patents because Abbott

did not show that it is likely to succeed in proving infringement of the “pharmaceutically

acceptable polymer” claim limitation. Andrx asserts that it cannot infringe literally or

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under the doctrine of equivalents because its product does not include a

“pharmaceutically acceptable polymer” as required by the claims. All of the asserted

claims of the ’718 patent—claims 1, 4, and 6—and claim 2 of the ’616 patent contain

this limitation.

The “pharmaceutically acceptable polymer” in the ’718 and ’616 patent serves as

the release controlling agent for the claimed extended release clarithromycin

compositions. ’718 patent, col. 1. l. 67 – col. 2 l. 2. Both sides concede that Andrx’s

product does not contain a polymer, but instead uses glyceryl monostearate (“GMS”) as

its release controlling ingredient. Abbott therefore does not assert that Andrx infringes

the claims of the ’718 and ’616 patents literally, but solely under the doctrine of

equivalents. The parties dispute whether GMS is properly referred to as a wax or a fat

and whether it can be found to be an equivalent of the claimed polymer.

1. Claim Construction

When determining whether the Andrx product is likely to infringe the

“pharmaceutically acceptable polymer” claim limitation as an equivalent, we start with

construction of that claim term. The district court construed the term “pharmaceutically

acceptable polymer” in its preliminary injunction order for defendant Teva.

The ’718 patent description of the “pharmaceutically acceptable polymer”
uses a closed term. Claim drafters often use the term “group of” to signal
a Markush group, which lists specified alternatives in a patent claim . . . .
By its nature, a Markush group is closed. The ’718 patent describes the
“pharmaceutically acceptable polymer” as “a water-soluble hydrophilic
polymer selected from the group consisting of polyvinylpyrrolidine,
hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose,
vinyl acetate/crotonic acid copolymers, methacrylic acids copolymers,
maleic anhydride/methyl vinyl ether copolymers and derivatives and
mixtures thereof.” . . . The term excludes other forms of polymers, such as
hydrophobic or water insoluble substances (e.g., wax).

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Teva I, slip op. at 11. The court subsequently adopted that construction for purposes of

the preliminary injunction proceedings against Andrx despite Abbott’s protest that the

district court’s construction in Teva I was overly narrow.

Abbott urges this Court to modify its construction of the phrase
“pharmaceutically acceptable polymer” from its previous opinion in the
related Teva matter. . . . When a term is undefined, the first place a court
is to look for a definition is the specification. This Court followed that
procedure, looked in the specification, and read the Markush group
containing definition there. It is not persuaded by the case law Abbott
cites that it erred in so doing and declines to alter its construction.

Ranbaxy-Andrx, slip op. at 40-41 (citation omitted).

Abbott argues, as it did to the district court, that the district court erred in its claim

construction because it relied on “Markush group” language in the specification, i.e.,

language indicating that the claimed pharmaceutically acceptable polymer is “selected

from the group consisting of” the polymers expressly identified in the specification.

Given that the specification used the “selected from the group of” language, the district

court limited the pharmaceutically acceptable polymers to those listed. Abbott argues

that this was erroneous because limiting claim scope based on Markush language only

applies when the phrase is used in the claims, not in the written description.

Abbott also disagrees with Andrx’s contention that the written description

provides an explicit definition of “pharmaceutically acceptable polymer” that should

overcome the canon that the term should be given its ordinary meaning to one of skill in

the art in the context of the patent. Further, Abbott argues that the patent does not

include any intentional disclaimer or disavowal of claim scope of the polymer limitation.

It urges that the specification merely identifies exemplary polymers that are suitable for

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use in the invention and does not provide a definition. It notes that when defining other

terms in the patent, the ’718 patent explicitly states what the term “means.”

The district court’s claim construction, Abbott argues, would also violate the

doctrine of claim differentiation because claims 2 and 3, which depend from claim 1

expressly claim the more specific types of polymers to which the court limited the term.

Accordingly, Abbott asserts that the correct construction of “pharmaceutically

acceptable polymer” is according to the plain and ordinary meaning that one of skill

would understand it to have in the context of the patent—“any polymer, suitable for use

in pharmaceutical compositions to be administered in humans that, alone or together

with other polymers, is capable of forming a matrix to control and extend drug-

dissolution release into the bloodstream.”

Andrx responds that Abbott wrongly relies on these principles of claim

construction to argue that the district court’s construction was impermissibly narrow.

First, Andrx argues that Markush language is just as limiting when used in the written

description as when it is used in a claim. Second, Andrx argues that Abbott misapplies

the doctrine of claim differentiation. Finally, Andrx asserts that Abbott’s construction

ignores an express definition of the term “pharmaceutically acceptable polymer” given in

the specification and instead imports limitations from preferred embodiments.

This court reviews the district court’s claim construction de novo on appeal.

Cybor Corp. v. FAS Techs, Inc., 138 F.3d 1448, 1454 (Fed. Cir. 1998). “[T]he words of

a claim ‘are generally given their ordinary and customary meaning.’” Philips v. AWH

Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (en banc) (quoting Vitronics Corp. v.

Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). Further, “the ordinary and

06-1101 22
customary meaning of claim term is the meaning that the term would have to a person

of ordinary skill in the art in question.” Id. at 1313. The court looks to sources such as

the words of the claims themselves, the written description of the patent, and extrinsic

evidence to ascertain the meaning of the term “pharmaceutically acceptable polymer.”

Id. at 1314.

First, “the claims themselves provide substantial guidance as to the meaning of

particular claim terms.” Id. at 1314. Claim 1 of the ’718 patent requires a composition

that includes only a “pharmaceutically acceptable polymer.” ’718 patent, col. 11 ll. 31-

32. Claim 2, not asserted here, depends from claim 1 and further requires that the

pharmaceutically acceptable polymer “is a hydrophilic water-soluble polymer.” Id., col.

11 ll. 39-40. Claim 3, also not asserted in this case, depends from claim 2 and more

specifically requires that

the polymer is selected from the group consisting of polyvinylpyrrolidine,
hydroxypropyl cellulose, hydroxypropylmethyl ceullulose, methyl cellulose,
vinyl acetate/crotonic acid copolymers, methacrylic acid copolymers,
maleic anhydride/methyl vinyl ether copolymers and derivatives and
mixtures thereof.

Id., col. 11 ll. 42-47. Therefore, the language of the claims and claim differentiation

imply that the “pharmaceutically acceptable polymer” term in claim 1 is likely broader

than the “hydrophilic water-soluble polymer” described in claim 2 and encompasses

more compounds than those listed in claim 3.

Next, the claims “‘must be read in view of the specification, of which they are a

part.’ . . . [I]t is the single best guide to the meaning of a disputed term.” Phillips, 415

F.3d at 1315 (citations omitted). Here, the specification describes:

The pharmaceutically acceptable polymer is a water-soluble hydrophilic
polymer selected from the group consisting of polyvinylpyrrolidine,

06-1101 23
 hydroxypropyl cellulose, hydroxypropyImethyl cellulose, methyl cellulose,
vinyl acetate/crotonic acid copolymers, methacrylic acid copolymers,
maleic anhydride/methyl vinyl ether copolymers and derivatives and
mixtures thereof. Preferably, the polymer is selected from hydroxypropyl
cellulose, hydroxypropylmethyl cellulose, and methyl cellulose. More
preferably, the polymer is hydroxypropylmethylcellulose. Most preferably,
the polymer is a low viscosity hydroxypropylmethyl cellulose with viscosity
ranging from about 50 cps to about 200 cops. The most preferred low
viscosity polymer is a hydroxypropylmethyl cellulose with a viscosity of
about 100 cps, commercially available under the Tradename Methocel™ K
100 LV from The Dow Chemical Company.

’718 patent, col. 3 l. 65 – col. 4 l. 14.

The district court focused on the “selected from the group consisting of” phrase in

the specification to hold that there was a Markush group and therefore Abbott was

limited to the listed polymers. A Markush group is a form of drafting a claim term that is

approved by the PTO to serve a particular purpose when used in a claim—to limit the

claim to a list of specified alternatives. Gillette Co. v. Energizer Holdings, Inc., 405 F.3d

1367, 1372 (Fed. Cir. 2005); Manual of Patent Examining Procedure § 803.2 (8th ed.

2001). The term “Markush group” does not have any meaning within the context of a

written description of a patent and therefore to the extent the district court relied on the

Markush group language to limit its construction to the compounds listed in the written

description, it erred.

The district court also appears to have grounded its claim construction on the

theory that the “pharmaceutically acceptable polymer” is explicitly defined in the written

description when it states, “The pharmaceutically acceptable polymer is a water-soluble

hydrophilic polymer . . . .” ’718 patent, col. 1 ll. 65-66 (emphasis added). Although a

term may have an ordinary meaning to one of ordinary skill in the art, the patentee may

“expressly define terms used in the claims.” Phillips 415 F.3d at 1321 (quoting

06-1101 24
Vitronics, 90 F.3d at 1582. The patentee here states in the written description that “a

pharmaceutically acceptable polymer is” a specific subset of polymers. The word “is”

may signify that a patentee is serving as its own lexicographer. However, there is

significant evidence at this stage of the litigation to believe that the patentee here was

not providing a definition of the “pharmaceutically acceptable polymer” claim term in the

written description. First, the ’718 patent unambiguously provides definitions of other

claim terms, that may be different from the ordinary understanding of a person of skill in

the art, by stating that the term has a particular meaning within the patent. See, e.g.,

’718 patent, col. 3 ll. 34-35 (“‘Erythromycin derivative’ as used herein, means . . . .”

(emphasis added)); col. 3, ll. 40-41 (“‘Pharmaceutically acceptable’ as used herein,

means . . . .” (emphasis added)). In contrast, the written description states that the

“pharmaceutically acceptable polymer is . . . ,” which does not as unambiguously signify

that the description provided is definitional. Further, neither party’s expert declared that

the language in the written description is purely definitional from the point of view of one

of skill in the art. Indeed, the two experts offer differing constructions as to how the term

“pharmaceutically acceptable polymer” would be understood by one of ordinary skill in

the art, neither construction limiting the polymer to hydrophilic, water-soluble

substances. Decl. of Arthur H. Kibbe Ph.D. in Opp’n to Abbott Labs. Mot. for a Prelim.

Inj. Against Andrx Pharms. at 21-22, ¶ 46, 48 (“Kibbe Declaration”); Decl. of Gilbert

Stephen Banker, Ph.D, D.Sc., in Supp. of Abbott Labs.’ Application for a TRO and Mot.

for a Prelim. Inj. Against Andrx Pharms., Inc. at 12. Also, it appears that if the

“pharmaceutically acceptable polymer” is defined to be “a water-soluble hydrophilic

polymer,” that definition would not cover some of the very polymers listed because they

06-1101 25
are not water-soluble. See Kibbe Declaration at 22, ¶ 49. Finally, as noted above, the

claims of the ’718 patent do not support a conclusion that the “pharmaceutically

acceptable polymer” in claim 1 is limited by the “hydrophilic” or “water-soluble”

limitations in claim 2, or to the specific compounds listed in claim 3. We therefore

conclude that the district court erred at this preliminary stage in limiting the

“pharmaceutically acceptable polymer” term to hydrophilic, water-soluble compounds

selected from a list given in the written description of the ’718 and ’616 patents.

2. Infringement

Turning to infringement, Andrx argues that, under the district court’s claim

construction, the Andrx product cannot infringe the “pharmaceutically acceptable

polymer” claim limitation. The parties conceded below that there is no literal

infringement of the limitation by the GMS ingredient in the Andrx product. Ranbaxy-

Andrx, slip op. at 37. The district court found, however, that Abbott did show a

likelihood of success of proving that the Andrx product infringes under the doctrine of

equivalents. On appeal, Andrx argues that GMS cannot be an equivalent of the

“pharmaceutically acceptable polymer” term for two reasons: first, because it would

violate the specific exclusion principle; and second, because a finding of equivalence

would vitiate the claim limitation. We address each of these arguments in turn.

Andrx first contends that permitting its product to infringe would violate the

specific exclusion principle. This principle limits what can be claimed under the doctrine

of equivalents by mandating that “the concept of equivalency cannot embrace a

structure that is specifically excluded from the scope of the claims.” Athletic

Alternatives, Inc. v. Prince Mfg. Inc., 73 F.3d 1573, 1582 (Fed. Cir. 1996). According to

06-1101 26
Andrx, the district court’s claim construction consistently held that the pharmaceutically

acceptable polymer excludes other forms of polymers such as hydrophobic or water

insoluble substances such as waxes. Therefore, any equivalence that encompasses

hydrophobic or water insoluble substances, Andrx argues, would violate the specific

exclusion principle. As discussed above, we hold that the district court erred by limiting

the scope of pharmaceutically acceptable polymers covered by the claims to hydrophilic

or water-soluble substances. Therefore, we need not consider Andrx’s argument that

specific exclusion bars the application of the doctrine of equivalents because GMS is a

hydrophobic, water-insoluble substance.

Andrx also argues that permitting its product to infringe the “pharmaceutically

acceptable polymer” term under the doctrine of equivalents would vitiate that claim

limitation. A finding of equivalence of the Andrx product is erroneous as a matter of law,

Andrx contends, because the Andrx product “employs a material[, GMS] that is the

exact opposite of the material recited in the claims of the ’718 patent (polymer vs.

nonpolymer (or even further, hydrophilic water soluble polymer vs. hydrophobic water

insoluble nonpolymer)).” Andrx argues that, regardless of whether GMS meets the test

for factual equivalence by performing substantially the same function in substantially the

same way to achieve substantially the same result, a finding of equivalence by

something that is the opposite of the claimed limitation would essentially read the

limitation out of the claim. Andrx also argues that GMS was well known in the prior art,

but not claimed by Abbott in its claims. Therefore, Andrx contends, allowing GMS to

infringe as an equivalent would seriously undermine the public notice function required

by patent claims.

06-1101 27
 Abbott responds that under either its asserted claim construction or that adopted

by the district court, the equivalence of GMS to the claimed “pharmaceutically

acceptable polymer” would not vitiate the claim limitation because the district court

found that GMS was an equivalent of the polymer limitation under the function-way-

result test. Andrx did not appeal the factual equivalence, so Abbott argues that Andrx

has no basis for arguing that the claim term is vitiated by a finding of equivalence.

Andrx replies that Abbott’s arguments regarding factual equivalence are immaterial to

the issue on appeal, whether a water insoluble hydrophobic non-polymeric substance,

can be considered insubstantially different from its antithesis, the claimed water soluble

hydrophilic polymer.

On the issue of vitiation, the district court held

Andrx argues that a finding of equivalency vitiates the claim by reading the
pharmaceutically acceptable polymer limitation out of it. That is incorrect.
A finding of equivalency under the doctrine of equivalents is a fact-specific
inquiry. It does not require a revision of the claim language or limitation.

Ranbaxy-Andrx, slip op. at 44 n.17.

A claim element is not vitiated merely because it does not literally exist in the

accused product—“such an interpretation of the ‘all elements’ rule would swallow the

doctrine of equivalents entirely.” Depuy Spine, Inc. v. Medtronic Sofamor Danek, Inc.,

469 F.3d 1005, 1018 (Fed. Cir. 2006). Rather,

[a] holding that the doctrine of equivalents cannot be applied to an
accused device because it ‘vitiates’ a claim limitation is nothing more than
[(1)] a conclusion that the evidence is such that no reasonable jury could
conclude that an element of an accused device is equivalent to an
element called for in the claim, or [(2)] that the theory of equivalence to
support the conclusion of infringement otherwise lacks legal sufficiency.

Id. at 1018-19.

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 Here, Andrx appears to argue the second type of vitiation described by Depuy

Spine—that Abbott’s theory as to the “polymer” claim element is legally insufficient to

prove equivalence. Specifically, Andrx argues that GMS, a hydrophobic, non-polymeric

substance, is the antithesis of the required polymer. See Planet Bingo v. Gametech

Int’l, No. 05-1476, slip op. at 13 (Fed. Cir. Dec. 12, 2006) (explaining that a theory of

equivalence may be legally insufficient when the accused product contains the

antithesis of the claim limitation). Therefore, Abbott’s assertion that it can avoid a

finding of vitiation because it showed factual equivalence does not address Andrx’s

argument that Abbott’s theory of equivalence is legally insufficient. It also appears that

the district court did not consider this aspect of vitiation. Rather, the court addressed

only whether GMS could factually be an equivalent of the polymer limitation.

Nevertheless, as discussed above, we hold that the district court erred in

construing the “pharmaceutically acceptable polymer” claim term as only covering

hydrophilic, water-soluble substances. Because this erroneous construction forms the

basis for Andrx’s vitiation arguments that GMS cannot be an equivalent of the required

polymer, we reject those arguments.

We are left with the district court finding that GMS could be factually equivalent to

the required polymer under its erroneous claim construction—that GMS performs the

same function, in the same way, to achieve the same result as the “pharmaceutically

acceptable polymer” in the claims. Ranbaxy-Andrx, slip op. at 44. Andrx does not

argue in this appeal that the district court erred in this finding of factual equivalence.

Although the district court’s equivalence analysis applied an erroneous claim

construction, its conclusion regarding equivalence would clearly also apply under a

06-1101 29
claim construction that was not erroneously narrowed as explained above. Therefore,

we affirm the district court’s finding, based on the preliminary record, that Abbott

showed a likelihood of success in proving infringement of claims 1, 4, and 6 of the ’718

patent and claim 2 of the ’616 patent under the doctrine of equivalents.

3. Infringement of the ’407 Patent

Because we hold that the district court did not err in granting a preliminary

injunction based on the ’718 and ’616 patents, we need not reach whether the court

erred in also basing its preliminary injunction on the ’407 patent.

C. Other Preliminary Injunction Factors

Other than likelihood of success on the merits, the other factors relevant to the

district court’s decision to grant or deny a preliminary injunction are (1) irreparable harm

if the injunction is not granted; (2) the balance of hardships between the parties; and (3)

the public interest. As Andrx does not challenge the district court’s findings on these

factors on appeal, we do not disturb the district court’s conclusion that these factors

weigh in Abbott’s favor.

CONCLUSION

Because Abbott has shown a likelihood of success in proving infringement of at

least one claim and the district court found that Andrx did not show it was likely to

prevail in its defense, which was a finding unchallenged on appeal, we affirm.6

AFFIRMED

6
Nothing in this opinion precludes either Abbott or Andrx from seeking in
district court either vacation of the injunction currently appealed or a new injunction
based on matters not previously presented to the district court.

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