Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-caDC-04-05211/USCOURTS-caDC-04-05211-0/pdf.json

Nature of Suit Code: 890
Nature of Suit: Other Statutory Actions
Cause of Action: 

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United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued December 6, 2004 Decided December 21, 2004

No. 04-5211

APOTEX, INC.,

APPELLANT

v.

FOOD & DRUG ADMINISTRATION, ET AL.,

APPELLEES

Appeal from the United States District Court

for the District of Columbia

(No. 04cv00605)

William A. Rakoczy argued the cause for appellant. With

him on the briefs were Christine J. Siwik, Matthew O. Brady,

Amy D. Brody, Lara Monroe-Sampson, and Arthur Y. Tsien.

Charles J. Raubicheck argued the cause for appellee

Purepac Pharmaceutical Company. With him on the brief was

William B. Schultz. Ronald H. Weich entered an appearance.

Howard S. Scher, Attorney, U.S. Department of Justice,

argued the cause for federal appellees. With him on the brief

were Peter D. Keisler, Assistant Attorney General, Kenneth L.

Wainstein, U.S. Attorney, Douglas N. Letter, Attorney, Alex M.

Azar, II, General Counsel, U.S. Department of Health & Human

USCA Case #04-5211 Document #866699 Filed: 12/21/2004 Page 1 of 17
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Services, Daniel E. Troy, Chief Counsel, and Karen E. Schifter,

Counsel.

Before: EDWARDS, SENTELLE, and RANDOLPH, Circuit

Judges.

Opinion for the Court filed by Circuit Judge EDWARDS.

EDWARDS, Circuit Judge: Since December 2002, the

District Court has issued three decisions in connection with

disputes between Apotex, Inc. ("Apotex") and Purepac

Pharmaceutical Co. ("Purepac") over the marketing of a generic

version of the drug gabapentin. The Food and Drug

Administration ("FDA" or "agency") has approved gabapentin,

sold by Pfizer, Inc. ("Pfizer") under the brand name Neurontin,

for the treatment of epilepsy. The first two decisions, Purepac

Pharmaceutical Co. v. Thompson, 238 F. Supp. 2d 191 (D.D.C.

2002) ("Purepac I"), and TorPharm, Inc. v. Thompson, 260 F.

Supp. 2d 69 (D.D.C. 2003) ("TorPharm"), were affirmed by this

court in a consolidated appeal. See Purepac Pharm. Co. v.

Thompson, 354 F.3d 877 (D.C. Cir. 2004) ("Purepac II"). 

At issue in this case is a dispute over the proper

interpretation and application of the pre-amended version of the

180-day generic marketing exclusivity provision of the Federal

Food, Drug, and Cosmetic Act ("FDCA"), 21 U.S.C. §

355(j)(5)(B)(iv) (2000) (amended 2003). The parties disagree

over whether the pre-2003 version of this statutory provision

adopts a "patent-based" approach or "first-filer" approach in

establishing the 180-day period for generic marketing

exclusivity. Applying a patent-based interpretation of §

355(j)(5)(B)(iv), FDA awarded Purepac two separate periods of

180-day exclusivity for the same generic gabapentin drug.

Purepac's first exclusivity period has expired. But the second

exclusivity period, which FDA awarded on the basis of a laterlisted patent, is now running and will not expire until April

2005. Meanwhile, FDA has delayed final approval of Apotex's

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application to market its generic version of gabapentin pending

the expiration of Purepac's period of marketing exclusivity.

Apotex claims that FDA erred in awarding multiple 180-day

periods of marketing exclusivity for the same drug when, in its

view, the statute allows only awards for a single period of

exclusivity to the first applicant. 

Apotex filed the present suit in District Court against FDA

and federal officials (collectively "federal appellees"),

advancing Apotex's interpretation of § 355(j)(5)(B)(iv) and

seeking an injunction directing FDA to issue final approval for

Apotex's gabapentin application. Purepac intervened as a

defendant. After consolidating Apotex's motion for a

preliminary injunction and defendants' motions to dismiss or for

summary judgment, the District Court granted summary

judgment to defendants. The District Court's judgment rested on

two grounds. First, the District Court ruled that res judicata

barred Apotex's action, because the parties in this case are the

same parties who appeared in TorPharm; a final judgment was

rendered against Apotex in TorPharm; the causes of action in

this case and TorPharm share a common nucleus of facts; there

has been no intervening change in the law; and there have been

no material changes in the facts since the judgment in

TorPharm. In the alternative, the District Court held that, even

if res judicata did not apply, the defendants would be entitled to

summary judgment, because FDA's interpretation of §

355(j)(5)(B)(iv) was reasonable and thus entitled to deference.

We agree that res judicata bars Apotex from bringing this

suit. Therefore, we affirm the judgment of the District Court on

this ground alone. We vacate the District Court's alternative

holding reaching the merits of whether FDA's interpretation of

21 U.S.C. § 355(j)(5)(B)(iv) is reasonable. 

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I. BACKGROUND

A. Statutory and Regulatory Framework

The FDCA requires that companies seeking to market a

drug that has not previously been approved by FDA submit a

New Drug Application ("NDA") to FDA. See 21 U.S.C. §

355(b)(1) (2000), amended by Pediatric Research Equity Act of

2003, Pub. L. No. 108-155, § 2(b), 117 Stat. 1936, 1941 (2003).

NDAs are usually lengthy, and they must include, among other

things, evidence surrounding the drug's safety and information

about any patents that cover or might cover the drug. Purepac

Pharm. Co. v. Thompson, 354 F.3d 877, 879 (D.C. Cir. 2004)

("Purepac II") (citing 21 U.S.C. § 355(b)(1)). 

In 1984, Congress passed the Hatch-Waxman Amendments

to the FDCA. See Drug Price Competition and Patent Term

Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585

(1984) ("Hatch-Waxman"). Hatch-Waxman eased the process

of generic drug approval by allowing companies seeking to

market generic versions of approved drugs to submit

Abbreviated New Drug Applications ("ANDAs"). ANDAs must

contain, among other things, information demonstrating that the

generic version is the bioequivalent of the approved version of

the drug. See 21 U.S.C. § 355(j)(2)(A)(iv) (2000). 

ANDAs must also address patents that apply or might apply

to the drug for which the ANDA is submitted. ANDA

applicants can satisfy this requirement by making one of four

certifications with regard to the patent's claim on the drug. Id.

§ 355(j)(2)(A)(vii). The relevant certification for the purposes

of this case, known as a "paragraph IV certification," requires

an ANDA applicant to certify that "such patent is invalid or will

not be infringed by the manufacture, use, or sale of the new drug

for which the application is submitted." Id. §

355(j)(2)(A)(vii)(IV). When an ANDA includes a paragraph IV

certification, the ANDA applicant must notify the owner of the

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patent and the holder of the NDA for the approved drug. See id.

§ 355(j)(2)(B)(i). If a patent infringement lawsuit is brought

against the ANDA applicant within 45 days from the date notice

is received, FDA's approval of the ANDA is automatically

stayed for 30 months. See id. § 355(j)(5)(B)(iii). 

An ANDA applicant who submits a paragraph IV

certification is entitled under certain circumstances to a 180-day

period of generic marketing exclusivity during which no other

company can market a generic version of the drug. See id. §

355(j)(5)(B)(iv). This exclusivity provision was amended in

2003, but this case arose under § 355(j)(5)(B)(iv) as it existed

prior to the 2003 Amendments. See Medicare Prescription

Drug, Improvement, and Modernization Act of 2003, Pub. L.

No. 108-173, § 1102, 117 Stat. 2066, 2457-60 (2003) ("2003

Amendments"). All references to § 355(j)(5)(B)(iv) are to the

statute as it existed prior to the 2003 Amendments. 

Because we conclude that Apotex is barred by res judicata

from bringing this case, we need not provide an elaborate

discussion of this generic marketing exclusivity provision.

Rather, what is important here is that the parties have advanced

competing interpretations of § 355(j)(5)(B)(iv). These

competing interpretations emanate from the fact that NDA

holders may receive additional patents that claim an approved

drug, or that claim a method of use for the drug, after the

approval of their NDAs. Thus, an ANDA applicant who filed

the first ANDA with a paragraph IV certification for a particular

drug may not be the first ANDA applicant to file paragraph IV

certifications for all patents that claim the drug. 

Consistent with FDA's determination in this case, the

federal appellees and Purepac understand § 355(j)(5)(B)(iv) to

allow a company to be eligible for a period of generic marketing

exclusivity if it was the first ANDA applicant to file a paragraph

IV certification for a particular patent, once the other statutory

triggers are satisfied, even if another company had previously

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filed a paragraph IV certification for another patent claiming the

same drug. Under this interpretation, multiple companies could

be eligible for generic marketing exclusivity, and multiple

periods of exclusivity are possible. This is the so-called "patentbased approach." By contrast, Apotex argues that §

355(j)(5)(B)(iv) should be interpreted to grant generic marketing

exclusivity only once – i.e., only to the generic manufacturer

who filed the first ANDA with a paragraph IV certification for

any patent involving a particular drug product, and only based

on that first paragraph IV certification. This is the "first-filer

approach." 

Although no court had addressed these competing

interpretations before January 2004, the possible tension

between them has been apparent since at least 1999. In August

of that year, FDA issued a proposed rule that would have

adopted the first-filer approach. See 180-Day Generic Drug

Exclusivity for Abbreviated New Drug Applications, 64 Fed.

Reg. 42,873, 42,875 (Aug. 6, 1999) ("August 1999 proposed

rule"). The agency never implemented the August 1999

proposed rule, however, and instead continued to apply the

patent-based approach in disputes surrounding generic

marketing exclusivity. See, e.g., Letter from FDA's Office of

Generic Drugs ("OGD") to Genpharm, Inc. of 11/16/01, Joint

Appendix ("J.A.") 1124, 1128-30; Letter from OGD to

American Pharmaceutical Partners, Inc. of 2/4/03, J.A. 1149,

1152-54. The August 1999 proposed rule was formally

withdrawn in 2002. See 180-Day Generic Drug Exclusivity for

Abbreviated New Drug Applications, 67 Fed. Reg. 66,593 (Nov.

1, 2002). 

Before turning to the factual background of the present

dispute, we note that the four types of certifications enumerated

in 21 U.S.C. § 355(j)(2)(A)(vii) are not the only mechanisms by

which an ANDA applicant can address a potentially relevant

patent. A generic company can instead submit a statement

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pursuant to 21 U.S.C. § 355(j)(2)(A)(viii) ("section viii

statement"). A section viii statement asserts that a patent does

not prevent FDA from approving the company's ANDA because

the ANDA applicant seeks to market the drug for a use other

than that covered by the patent. See 21 U.S.C. §

355(j)(2)(A)(viii). As we have previously explained, applicants

use paragraph IV certifications to challenge the validity of

applicable patents, whereas they submit section viii statements

to assert that patents do not apply. Purepac II, 354 F.3d at 880.

ANDA applicants who submit section viii statements are not

eligible for generic marketing exclusivity pursuant to 21 U.S.C.

§ 355(j)(5)(B)(iv).

B. Facts

As noted above, this case involves gabapentin, a drug sold

by Pfizer under the name Neurontin, which FDA has approved

for the treatment of epilepsy. In 1993, FDA approved Neurontin

capsules based on a NDA submitted by Warner-Lambert Co.

("Warner-Lambert"), which later assigned Pfizer the rights to

Neurontin. In 1997, Warner-Lambert submitted information to

FDA on two patents that were not part of its original NDA

filing: U.S. Patent Nos. 4,894,476 ("'476 patent"), claiming a

crystal form of gabapentin, and 5,084,479 ("'479 patent"),

claiming a method for using gabapentin to treat

neurodegenerative diseases. See Letter from Parke-Davis to

FDA of 7/1/97, J.A. 445, 448. In 2000, Warner-Lambert

submitted information on an additional patent, U.S. Patent No.

6,054,482 ("'482 patent"), claiming a pharmaceutical

composition of gabapentin. See Submission from WarnerLambert to FDA of 4/25/00, J.A. 452, 453. 

In 1998, Purepac submitted ANDAs for a generic version

of gabapentin. Purepac's ANDAs contained a paragraph IV

certification for the '476 patent and a section viii statement for

the '479 patent. In May 2000, Purepac submitted a paragraph IV

certification to FDA with respect to the '482 patent. Purepac

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was the first ANDA applicant to file paragraph IV certifications

for the '476 and '482 patents. See Purepac Pharm. Co. v.

Thompson, 238 F. Supp. 2d 191, 198-200 (D.D.C. 2002)

("Purepac I").

Apotex also submitted an ANDA for gabapentin in 1998,

and Apotex ultimately submitted paragraph IV certifications for

all three patents, as well as a section viii statement for the '479

patent. Id. at 200. (Apotex was at that time an affiliate of

TorPharm Corp.; the distinction between Apotex and TorPharm

Corp. is of no relevance for this appeal, and we refer to the

companies both individually and collectively as "Apotex.") 

In two separate proceedings filed in 1998, Warner-Lambert

sued Purepac and Apotex for infringement of the '476 and '479

patents. Although Warner-Lambert ultimately lost both suits,

the ANDAs filed by Purepac and Apotex were stayed for 30

months pursuant to 21 U.S.C. § 355(j)(5)(B)(iii). See Purepac

I, 238 F. Supp. 2d at 200-01 & n.14. In 2000, Warner-Lambert

initiated lawsuits against both Purepac and Apotex for

infringement of the '482 patent. Under FDA's then-prevailing

interpretation of the statute, these lawsuits triggered additional

30-month stays before FDA could approve the companies'

ANDAs. See id. at 201 & n.15. Purepac's 180-day exclusivity

period based on the paragraph IV certification for the '476 patent

began in 2001, when all statutory conditions were satisfied.

However, Warner-Lambert's '482 infringement suit precluded

FDA from granting final approval of Purepac's ANDA, so

Purepac's exclusivity period passed without Purepac having the

opportunity to market the drug. 

In April 2002, FDA notified Purepac that, because, in the

agency's view, a section viii statement was not appropriate for

the '479 patent, Purepac could not receive final approval of its

ANDA before it filed a certification for the '479 patent. See id.

at 199. Purepac filed suit in District Court challenging FDA's

decision. Purepac also sought to enjoin FDA from approving

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Apotex's ANDA for gabapentin, because of the adverse

consequences of such approval for any exclusivity Purepac

would have pursuant to its paragraph IV certification for the '482

patent. See id. at 211 & n.27. Apotex intervened as a defendant,

arguing among other things that Purepac's claims were barred by

the doctrine of laches. See id. at 201. Apotex did not present

the first-filer interpretation of § 355(j)(5)(B)(iv). Because

Purepac's paragraph IV certification for the '476 patent was the

first paragraph IV certification submitted for any patent

claiming gabapentin, the first-filer approach would not have

promoted generic marketing exclusivity for the ANDAs relating

to the '479 an '482 patents. Rather, an argument founded on the

first-filer approach would have rested on the premise that no

ANDA, save for the one related to the '476 patent, could serve

as the basis for generic marketing exclusivity to the

disadvantage of competing claims. Apotex did not raise this

argument in the Purepac I litigation. 

The District Court ruled in Purepac's favor on the section

viii issue, ordering FDA to accept Purepac's section viii

statement. See Purepac I, 238 F. Supp. 2d at 193. However, the

court declined to enjoin FDA from approving Apotex's ANDA,

stating that it was up to FDA to determine, in the first instance,

the effect of the court's decision. See id. at 211-12. 

In response to Purepac I, FDA sought comments from

generic gabapentin applicants, including Apotex and Purepac.

See Letter from OGD to Apotex of 12/18/02, J.A. 741; Letter

from OGD to Purepac of 12/18/02, J.A. 896. Apotex submitted

several letters, which argued that, notwithstanding Purepac I,

Apotex was entitled to at least share in any exclusivity period

with Purepac, because Apotex was the first to file a paragraph

IV certification for the '479 patent. In addition, the letters

asserted that Apotex was the first company to submit a valid

paragraph IV certification for the '482 patent. Once again,

Apotex did not raise the first-filer approach to §

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355(j)(5)(B)(iv). See, e.g., Letter from Gilbert's to OGC of

1/7/03, J.A. 984; Letter from Gilbert's to OGC of 1/9/03, J.A.

1031. 

On January 28, 2003, FDA issued a letter ruling addressing

the dispute between Purepac and Apotex concerning generic

marketing exclusivity for gabapentin. FDA sided with Purepac,

ruling that Apotex was not entitled to any exclusivity based on

its paragraph IV certification for the '479 patent, and that

Purepac alone would be entitled to exclusivity based on the '482

patent. Letter from OGD to Apotex and Purepac of 1/28/03,

J.A. 743, 744, 747-50. 

Apotex challenged FDA's actions in District Court. Once

again, Apotex failed to advance the first-filer interpretation of 21

U.S.C. § 355(j)(5)(B)(iv). Rather, Apotex argued for a patentbased interpretation of the statute, contending that Apotex was

entitled to exclusivity based on its paragraph IV certification for

the '482 patent, or that Apotex should at least be eligible for a

period of shared exclusivity along with Purepac based on

Apotex's submission of the first paragraph IV certification for

the '479 patent. See Letter from OGD to TorPharm of 2/6/04,

J.A. 802, 803 (quoting TorPharm's Memorandum in Support of

its Motion for Preliminary Injunction (Feb. 14, 2003)). In April

2003, the District Court rejected Apotex's challenge, entering

summary judgment in favor of FDA. TorPharm, Inc. v.

Thompson, 260 F. Supp. 2d 69, 71 (D.D.C. 2003) ("TorPharm").

Apotex appealed the District Court's decisions in both

Purepac I and TorPharm. Once again, Apotex failed to advance

the first-filer interpretation of 21 U.S.C. § 355(j)(5)(B)(iv). This

court consolidated the appeals and affirmed the District Court's

rulings in all respects on January 20, 2004. Purepac II, 354 F.3d

at 878-79. 

Less than two weeks before this court's decision in Purepac

II, District Court Judge Roberts issued a written order

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memorializing an oral decision in a separate action filed by

Apotex regarding generic marketing exclusivity for the drug

paroxetine. TorPharm, Inc. v. FDA, No. Civ. A. 03-2401, 2004

WL 64064 (D.D.C. Jan. 8, 2004) ("Paroxetine"), vacated as

moot, No. 04-5046 (D.C. Cir. Dec. 17, 2004). In Paroxetine,

Judge Roberts ruled that the plain language of 21 U.S.C. §

355(j)(5)(B)(iv) compelled the first-filer as opposed to the

patent-based interpretation of the statute. See id. Based on

Paroxetine, Apotex submitted a letter to FDA requesting

immediate approval of its gabapentin ANDA. For the first time,

Apotex asserted that FDA was bound to follow the first-filer

approach in awarding generic marketing exclusivity for

gabapentin. As explained above, under the first-filer approach,

Purepac's exclusivity for gabapentin stemmed solely from the

'476 patent, and that exclusivity period had expired. See Letter

from TorPharm to OGD of 1/15/04, J.A. 761, 762. 

On February 6, 2004, FDA rejected Apotex's request. The

agency concluded that Apotex had waived the argument as the

company had not previously raised it before FDA, the District

Court, or this court, despite having had the opportunity to do so

in the previous litigation concerning gabapentin. In fact, FDA

noted that Apotex had taken the opposite position – making

exclusivity arguments premised on the patent-based reading of

the statute. According to FDA, the doctrine of judicial estoppel

barred Apotex from advancing these inconsistent positions. See

Letter from OGD to TorPharm of 2/6/04, J.A. 802, 802-04. The

agency also rejected Apotex's contention that collateral estoppel

required that FDA adopt the first-filer approach in line with

Paroxetine, and announced that it would continue to apply the

patent-based approach in determining exclusivity for gabapentin

ANDAs. See id., J.A. 804.

Apotex challenged FDA's decision in District Court, and

Purepac intervened as a defendant. Speaking through Judge

Huvelle, the District Court ruled for the agency. Apotex, Inc. v.

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FDA, No. Civ. A. 04-605 (D.D.C. June 3, 2004) (oral decision),

reprinted in J.A. 8-34. The court held that Apotex's claims were

barred by res judicata, and that collateral estoppel did not

prevent FDA from implementing the patent-based approach to

§ 355(j)(5)(B)(iv) concerning gabapentin ANDAs. See id., J.A.

32. Judge Huvelle also went on to consider the merits of the

statutory interpretation question. Recognizing that she was not

bound by Judge Roberts' Paroxetine decision, Judge Huvelle

concluded that FDA's patent-based interpretation of 21 U.S.C.

§ 355(j)(5)(B)(iv) was reasonable, and that the court would defer

to it. See id., J.A. 32-34. Apotex filed the present appeal. 

II. ANALYSIS 

A. Standard of Review

We review the District Court's grant of summary judgment

de novo. Cruz v. Am. Airlines, Inc., 356 F.3d 320, 328 (D.C.

Cir. 2004). Because the material facts of this case are not in

dispute, "our task is to ensure that the District Court correctly

applied the relevant law to the undisputed facts." Beckett v. Air

Line Pilots Ass'n, 995 F.2d 280, 284 (D.C. Cir. 1993). 

B. Res Judicata 

Also known as claim preclusion, the doctrine of res judicata

holds that a judgment on the merits in a prior suit bars a second

suit involving identical parties or their privies based on the same

cause of action. Drake v. FAA, 291 F.3d 59, 66 (D.C. Cir.

2002). Res judicata plays a central role in advancing the

"purpose for which civil courts have been established, the

conclusive resolution of disputes within their jurisdictions."

Montana v. United States, 440 U.S. 147, 153 (1979). As the

Supreme Court has explained: "To preclude parties from

contesting matters that they have had a full and fair opportunity

to litigate protects their adversaries from the expense and

vexation attending multiple lawsuits, conserves judicial

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resources, and fosters reliance on judicial action by minimizing

the possibility of inconsistent decisions." Id. at 153-54.

In this case, Apotex does not dispute that TorPharm was a

judgment on the merits by a court of competent jurisdiction

involving the identical parties. Rather, Apotex argues res

judicata does not bar its suit because the cause of action here is

not identical to the cause of action in TorPharm. Apotex's

argument is unpersuasive.

"Whether two cases implicate the same cause of action

turns on whether they share the same 'nucleus of facts.'" Drake,

291 F.3d at 66 (quoting Page v. United States, 729 F.2d 818,

820 (D.C. Cir. 1984)). In pursuing this inquiry, the court will

consider "'whether the facts are related in time, space, origin, or

motivation, whether they form a convenient trial unit, and

whether their treatment as a unit conforms to the parties'

expectations or business understanding or usage.'" I.A.M. Nat'l

Pension Fund v. Indus. Gear Mfg. Co., 723 F.2d 944, 949 n.5

(D.C. Cir. 1983) (quoting 1B J. MOORE, MOORE'S FEDERAL

PRACTICE ¶ 0.410[1] (2d ed. 1983)). 

Apotex maintains that the facts of this case are not related

in time, space, origin, or motivation to those of TorPharm and

that they would not form a convenient trial unit. But TorPharm

and the case at bar each involve a dispute between Apotex and

Purepac over generic marketing exclusivity and final ANDA

approval for the drug gabapentin. Moreover, the relevant

patents – and the companies' submissions relating to those

patents – have not changed since Apotex filed suit in TorPharm.

Thus, the underlying facts of the two cases are closely related in

time, space, origin, and motivation, and they would have formed

a convenient trial unit. 

Apotex nonetheless insists that this case involves

submissions relating to the '476 patent, whereas TorPharm

involved submissions surrounding the '482 and '479 patents.

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Apotex Br. at 53-55. This is not an accurate description of the

two cases. Apotex chose not to present the first-filer

interpretation of 21 U.S.C. § 355(j)(5)(B)(iv) before the court in

TorPharm. Apotex's argument in this case is that, following the

first-filer approach, FDA has no authority under §

355(j)(5)(B)(iv) to award multiple 180-day periods of generic

marketing exclusivity for the same drug. Apotex could have

presented the same argument to challenge FDA's decision in

TorPharm. Apotex chose not to do so. There are no new facts.

Apotex is simply raising a new legal theory. This is precisely

what is barred by res judicata. See Drake, 291 F.3d at 66

("[U]nder res judicata, 'a final judgment on the merits of an

action precludes the parties or their privies from relitigating

issues that were or could have been raised in that action.'")

(quoting Allen v. McCurry, 449 U.S. 90, 94 (1980)) (emphasis

in original). 

Apotex also argues that res judicata does not apply here,

because Judge Roberts' decision in Paroxetine effected a

significant change in circumstances after TorPharm had issued.

Res judicata does not bar parties from bringing claims based on

material facts that were not in existence when they brought the

original suit. Drake, 291 F.3d at 66. And, in a small set of

cases, a change in controlling legal principles may allow a party

to relitigate a claim that would otherwise be barred by res

judicata. See Hardison v. Alexander, 655 F.2d 1281, 1288-89

(D.C. Cir. 1981) (stating that in general res judicata applies

even if there has been a subsequent change in the law of the

circuit, but noting that there are exceptions for reasons of

compelling public policy, such as cases involving important

questions of constitutional law). Neither exception applies here.

It is true that Judge Roberts' opinion in Paroxetine

embraced the legal theory that Apotex is advancing in this case,

but this was not a "change" either in the facts or the law

sufficient to overcome the effects of res judicata. The relevant

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facts here involve the effect of paragraph IV certifications

submitted by Purepac and TorPharm for the '476 and '482

patents. These certifications were submitted well before Apotex

brought suit in TorPharm. Moreover, Judge Roberts' decision

in Paroxetine is not a change in controlling legal principles.

Judge Huvelle was not bound by Judge Roberts' decision, from

which an appeal was pending, and neither Judge Roberts' nor

Judge Huvelle's decision established the law of the circuit. See

In re Executive Office of the President, 215 F.3d 20, 24 (D.C.

Cir. 2000) ("District Court decisions do not establish the law of

the circuit, nor, indeed, do they even establish the law of the

district.") (citations and internal quotations omitted). 

Apotex presents two additional arguments as to why res

judicata should not apply in this case, neither of which have

merit. First, Apotex argues that it would have been

impracticable for Apotex to have presented the first-filer

interpretation of 21 U.S.C. § 355(j)(5)(B)(iv) in TorPharm,

because the company elected to argue that it was entitled to

generic marketing exclusivity for gabapentin under the patentbased approach to the statute. This argument fails. It is true that

res judicata does not prevent parties from later bringing claims

that "would have been utterly impracticable to join" in an earlier

suit. United States Indus., Inc. v. Blake Constr. Co., 765 F.2d

195, 205 n.21 (D.C. Cir. 1985). But it would not have been

"utterly impractical" for Apotex to raise the first-filer argument

to advance its cause in TorPharm. Indeed, at oral argument,

Apotex's counsel did not deny that Apotex could have presented

the first-filer approach as an alternative argument in TorPharm.

Recording of Oral Argument at 7:52-:59. Rather than seeking

the advantage that flows from having alternative arguments,

either of which in Apotex's view would have supported its claim

in TorPharm, Apotex chose instead to argue solely in favor of

the patent-based approach, which is diametrically opposed to the

first-filer theory that Apotex advances in this case. 

USCA Case #04-5211 Document #866699 Filed: 12/21/2004 Page 15 of 17
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Second, Apotex claims that public policy considerations

weigh against applying res judicata in this case. We disagree.

There is no general public policy exception to the operation of

res judicata. See Federated Dep't Stores, Inc. v. Moitie, 452

U.S. 394, 401 (1981) (rejecting the court of appeals' reliance on

"simple justice" and "public policy" in declining to apply res

judicata, and stating: "There is simply 'no principle of law or

equity which sanctions the rejection by a federal court of the

salutary principle of res judicata.'") (quoting Heiser v. Woodruff,

327 U.S. 726, 733 (1946)). If there is any "public policy"

exception to res judicata, it applies only in very limited

circumstances, e.g., in cases implicating significant questions of

constitutional law where there has been a change in controlling

legal principles. See Hardison, 655 F.2d at 1288-89. 

The only argument Apotex offered in its opening brief as to

why this case might fit within the scope of a public policy

exception to res judicata is that, absent a favorable ruling from

this court, FDA will continue to apply the 180-day generic

marketing exclusivity provision under § 355(j)(5)(B)(iv) in a

way that defies congressional intent. Obviously, this argument

does not save Apotex from the res judicata bar in this case. The

statutory question raised by Apotex is no doubt compelling. But

its resolution must await another day, i.e., when a suit is

properly before the court calling into question FDA's

interpretation of 21 U.S.C. § 355(j)(5)(B)(iv).

Finally, because we affirm the District Court's judgment on

res judicata grounds, we vacate the District Court's alternative

holding addressing the merits of the statutory interpretation

question. 

III. CONCLUSION

Res judicata bars Apotex from bringing this suit.

Therefore, we affirm the judgment of the District Court on this

ground alone. We vacate the District Court's alternative holding

USCA Case #04-5211 Document #866699 Filed: 12/21/2004 Page 16 of 17
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purporting to resolve the parties' dispute over the interpretation

of 21 U.S.C. § 355(j)(5)(B)(iv). 

So ordered.

USCA Case #04-5211 Document #866699 Filed: 12/21/2004 Page 17 of 17