NOTE: This disposition is nonprecedential. 

United States Court of Appeals 

for the Federal Circuit 

__________________________ 

PURDUE PHARMA PRODUCTS L.P., 

AND NAPP PHARMACEUTICAL GROUP LTD., 

Plaintiffs-Appellants, 

AND

ORTHO-MCNEIL, INC., 

Plaintiff, 

v. 

PAR PHARMACEUTICAL, INC. 

AND PAR PHARMACEUTICAL COMPANIES, INC., 

Defendants-Cross Appellants. 

__________________________ 

2009-1553, -1592 

__________________________ 

Appeals from the United States District Court for the 

District of Delaware in consolidated Case No. 1:07-CV00255, Circuit Judge Kent A. Jordan (sitting by 

designation). 

____________________________ 

Decided: June 3, 2010 

____________________________ 
PURDUE PHARMA v. PAR PHARMACEUTICAL 2

ROBERT J. GOLDMAN, Ropes & Gray LLP, of East Palo 

Alto, California, argued for plaintiffs-appellants. With 

him on the brief were SASHA G. RAO; PABLO D. HENDLER 

and SONA DE, of New York, New York. 

DANIEL G. BROWN, Wilson Sonsini Goodrich & Rosati, 

of New York, New York, argued for defendants-cross 

appellants. With him on the brief were RON E. SHULMAN, 

of Palo Alto, California; JENNIFER KOH, of San Diego, 

California; and NICOLE W. STAFFORD, of Austin, Texas. 

__________________________ 

Before LOURIE, LINN, and DYK, Circuit Judges. 

LOURIE, Circuit Judge. 

Purdue Pharma Products L.P. and Napp Pharmaceutical Group Ltd. (collectively, “Purdue”) appeal from a 

decision of the United States District Court for the District of Delaware holding U.S. Patents 6,254,887 (“the 

’887 patent”) and 7,074,430 (“the ’430 patent”) invalid for 

obviousness. Par Pharmaceutical, Inc. and Par Pharmaceutical Companies, Inc. (collectively, “Par”) cross-appeal 

from the district court’s decision finding the ’887 and ’430 

patents not unenforceable due to inequitable conduct. We 

affirm. 
3 PURDUE PHARMA v. PAR PHARMACEUTICAL

BACKGROUND

Purdue owns the ’887 and ’430 patents, which claim 

controlled-release tramadol formations suitable for oncedaily oral dosing. Tramadol is an opioid analgesic used to 

treat moderate to moderately severe pain, including pain 

from arthritis. Certain claims further limit the tramadol 

formulation to certain dissolution rates and W50 values1

between ten and thirty-three hours. Ortho-McNeil, Inc. 

sells once-daily tramadol (branded as Ultram® ER) under 

a license from Purdue. Par filed an abbreviated new drug 

application (“ANDA”) seeking FDA approval to market 

generic Ultram® ER, and Purdue filed suit alleging infringement of claims 3, 13, 27, and 29 of the ’887 patent 

and 5, 7, and 11 of the ’430 patent. Par counterclaimed 

that the asserted patents were invalid under 35 U.S.C. § 

112 for lack of enablement and written description, invalid under § 103 for obviousness, and unenforceable due to 

inequitable conduct. 

After a five-day bench trial, the district court held 

that Par’s proposed generic tramadol product literally 

infringed the asserted patents, that the asserted patents 

were not unenforceable, but that the asserted claims were 

invalid for obviousness. Purdue Pharma Prods. L.P. v. 

Par Pharm., Inc., 642 F. Supp. 2d 329 (D. Del. 2009). 

With regard to invalidity, the district court held that the 

asserted claims would have been obvious in light of (1) 

U.S. Patent 5,580,578 (“Oshlack”), which describes formulations of opioid analgesics, including tramadol, for oncedaily dosing and (2) what was known in the art about 

tramadol and once-daily formulations. The court reasoned that the Oshlack patent taught the use of tramadol 

as one of fourteen different opioid analgesics to be used 

 1 The W50 value equals the width of an administered drug’s plasma profile (plasma concentration over 

time) at half the drug’s maximum plasma concentration. 
PURDUE PHARMA v. PAR PHARMACEUTICAL 4

and that any differences in incorporating tramadol as the 

active ingredient in a once-a-day formulation would have 

involved only routine experimentation. Id. at 369-73. 

The court then rejected Purdue’s claims of secondary 

considerations, finding evidence of copying not compelling 

in the ANDA context where bioequivalency is a prerequisite to FDA approval, and that Purdue’s evidence of 

commercial success was “underwhelming.” Id. at 373-74. 

With regard to unenforceability, the district court 

found that Par had failed to prove intent to deceive by 

clear and convincing evidence. Specifically, while finding 

that the applicants had withheld material experimental 

data and had submitted a materially misleading declaration (“the Malkowska declaration”), the district court 

found plausible the inference that the applicants were 

merely overly aggressive in trying to put a positive spin 

on the experimental results without intending to deceive 

the United States Patent and Trademark Office (“PTO”). 

In reaching that conclusion, the district court relied, inter

alia, on the credibility of Ms. Malkowska’s testimony and 

the applicants’ later disclosure of the more pertinent 

Napp repeat experiments generated for a foreign litigation. Id. at 375-79. 

Both Purdue and Par appealed. We have jurisdiction 

pursuant to 28 U.S.C. § 1295(a)(1).

DISCUSSION

Purdue appeals from the district court’s decision holding claims 3, 13, 27, and 29 of the ’887 patent and 5, 7, 

and 11 of the ’430 patent invalid as obvious. Par crossappeals from the decision that the asserted patents are 

not unenforceable due to inequitable conduct. Par also 

cross-appeals from the district court’s finding of infringement in light of the court’s claim construction, but, as that 
5 PURDUE PHARMA v. PAR PHARMACEUTICAL

argument merely asserts another ground for affirmance of 

non-liability, it is not appropriate for cross-appeal, Voda 

v. Cordis Corp., 536 F.3d 1311, 1324 n.4 (Fed. Cir. 2008), 

nor is it persuasive. We consider each appeal in turn. 

Obviousness 

While the ultimate question of obviousness under 35 

U.S.C. § 103 is a question of law, reviewed de novo, it is 

based on several underlying factual determinations, 

which we review after a bench trial for clear error. 

Golden Blount, Inc. v. Robert H. Peterson Co., 365 F.3d 

1054, 1058 (Fed. Cir. 2004). The relevant factual determinations include 1) the scope and content of the prior 

art, 2) the level of ordinary skill in the art, 3) the differences between the claimed invention and the prior art, 

and 4) evidence of secondary factors. Graham v. John 

Deere Co., 383 U.S. 1, 17-18 (1966). 

Purdue challenges the district court’s finding of obviousness on multiple grounds.2 First, Purdue argues that 

the district court erred in finding that it would have been 

obvious in light of Oshlack to select tramadol as an active 

ingredient for use in a once-daily formulation. Rather, 

according to Purdue, the prior art teaches away from 

 2 Purdue also argues that the district court made 

two factual errors, erroneously finding that (1) two patents, including Oshlack, were not before the PTO and (2) 

the use of tramadol disclosed in those patents did not 

represent work “by another” under § 102(e). Because the 

outcome is the same regardless whether Oshlack was 

before the PTO, we need not address this argument. As 

for Purdue’s § 102(e) argument, Purdue raises it for the 

first time on appeal, and thus it has been waived. See

Sage Prods., Inc. v. Devon Indus., Inc., 126 F.3d 1420, 

1426 (Fed. Cir. 1997). Even if it had not been waived, 

Purdue presented no evidence that the disclosures in the 

two cited patents were the invention of the inventors of 

the presently contested patents. 
PURDUE PHARMA v. PAR PHARMACEUTICAL 6

selecting tramadol, reporting it as unpredictable and 

poorly understood, and the development of a one-a-day 

formulation for tramadol involved time-intensive design 

(i.e., invention) not routine experimentation. Purdue next 

argues that the district court erred in finding that the 

claimed twenty-four hour therapeutic effect and W50

values were obvious since, at the time, there were no oral 

opioid formulations effective for greater than twelve hours 

and the W50 values, which were not disclosed in the prior 

art, do not emerge from routine experimentation. Finally, 

Purdue argues that the court gave insufficient weight to 

its secondary considerations of nonobviousness, including 

Par’s copying of the invention and Ultram® ER’s commercial success. 

Par responds that the district court correctly found 

that one skilled in the art would have been motivated to 

make the claimed tramadol formulation in light of Oshlack’s listing of tramadol for use in a once-daily formulation and the prior art’s reports of its favorable 

characteristics. According to Par, Purdue presented no 

evidence of unexpected results over the Oshlack patent’s 

controlled-release formulations and failed to rebut evidence that only routine experimentation was required to 

make the claimed formulation. Par also contends that the 

claimed twenty-four hour therapeutic effect and the 

claimed W50 values (the latter argument raised for the 

first time on appeal) were obvious as the Oshlack patent 

disclosed a formulation with a twenty-four hour effective 

blood concentration that would necessarily have a W50

value within the claimed range of ten to thirty-three 

hours. Finally, Par argues that the district court rightly 

rejected Purdue’s secondary considerations, correctly 

finding that evidence of copying is not compelling in the 

Hatch-Waxman context and that the evidence of commercial success was “underwhelming.” 
7 PURDUE PHARMA v. PAR PHARMACEUTICAL

We agree with Par and affirm the district court’s decision finding the ’887 and ’430 patents would have been 

obvious in view of Oshlack. Purdue’s asserted claims 

require (1) a tramadol formulation, (2) a controlledrelease coating, and (3) a dosing that is suitable for administration every twenty-four hours or that provides a 

therapeutic effect for about twenty-four hours. Some 

claims further recite very broad in vitro dissolution 

ranges, some claims recite an in vivo W50 value of between ten to thirty-three hours, and some claims recite a 

controlled-release coating consisting of a water-insoluble 

wax, a water-insoluble polymer, a water-insoluble cellulose, a mixture of the foregoing, or the water-insoluble 

cellulose polyvinylpyrrolidone. In comparison, Oshlack 

discloses a controlled-release tramadol formulation with a 

similarly broad, although truncated, dissolution profile 

that provides effective blood levels for about twenty-four 

hours. ’578 patent col.43 l.48–col.44 l.36 claims 43, 44, 

47. It also discloses at least one opioid analgesic formulation with a W50 value of approximately twelve hours. Id.

col.37 ll.28-31 Fig 8. And it discloses controlled-release 

coatings comprising polymethacrylate, a water-insoluble 

polymer, and polyvinylpyrrolidone. 

Purdue’s main argument is that a person of skill in 

the art would not have selected tramadol out of the myriad other possible active ingredients for use in a oncedaily formulation. But Oshlack makes that very selection; it lists tramadol as one of fourteen different opioid 

analgesics to use in a controlled-release formulation that 

provide effective blood levels for twenty-four hours. As 

such, Oshlack itself renders the selection of tramadol 

obvious regardless whether or not the patent lists 

tramadol as a preferred embodiment. See Perricone v. 

Medicis Pharm. Corp. 432 F.3d 1368, 1376 (Fed. Cir. 

2005) (“This court rejects the notion that one of [14 listed] 

ingredients cannot anticipate because it appears without 
PURDUE PHARMA v. PAR PHARMACEUTICAL 8

special emphasis in a longer list.”); see also Merck & Co. v. 

Biocraft Labs., Inc., 874 F.2d 804, 807 (Fed. Cir. 1989) 

(holding that the prior art’s disclosure of a multitude of 

combinations failed to render any particular formulation 

less obvious). 

Purdue’s alternative formulation of its argument, that 

the selection of a once-daily dose with twenty-four hour 

effect for tramadol was not obvious, similarly fails. 

Again, Oshlack expressly teaches once-daily formulations, 

see, e.g., Oshlack col.12 ll.17-18; col.33 ll.33-34; col.34 ll.4-

7, with dissolution rates designed to provide effective 

blood levels for about twenty-four hours, compare id.

col.12 ll.12-18, with id. col.43 l.48–col.44 l.9 claim 43. 

And it claims such formulations for use with tramadol. 

Id. col.44 ll.29-36 claim 47. To the extent that Purdue is 

arguing that the Oshlack patent fails to enable a oncedaily tramadol formulation, this argument also fails. For 

purposes of § 103, a prior art reference need not itself be 

enabled but is prior art for all that it discloses. Symbol 

Techs., Inc. v. Opticon, Inc., 935 F.2d 1569, 1578 (Fed. Cir. 

1991). Oshlack discloses a once-daily formulation of 

tramadol, and the district court found that in light of the 

knowledge in the art about once-daily formulations and 

about tramadol, persons of skill in the art would have 

been able to achieve a once-daily tramadol formulation 

with the claimed properties through routine experimentation. Purdue Pharma, 642 F. Supp. 2d at 373. We see no 

clear error in that finding. 

Although argued on appeal, Purdue does not appear 

to have distinguished the Oshlack patent on the basis of 

the claimed W50 values before the district court, waiving 

the argument. See Sage Prods., Inc. v. Devon Indus., Inc., 

126 F.3d 1420, 1426 (Fed. Cir. 1997). Yet, we note that 

Oshlack does in fact disclose a once-daily formulation 

with a W50 value within the broad range of ten to thirty-
9 PURDUE PHARMA v. PAR PHARMACEUTICAL

three hours claimed in claim 13 of the ’887 patent and 

claim 11 of the ’430 patent. Specifically, Figure 8 graphs 

the plasma concentration of the opioid analgesic morphine 

from Example 20 over time, revealing a W50 value of 

approximately twelve hours. Thus, Oshlack itself provides a motivation to prepare a once-a-day tramadol 

formulation with a W50 value within the claimed range 

whether or not such a W50 value is, as the district court 

found, necessarily a characteristic of a one-a-day 

tramadol formulation. Purdue Pharma, 642 F. Supp. 2d 

at 373. 

Finally, we also reject Purdue’s argument that the 

district court placed insufficient weight on its secondary 

considerations of nonobviousness. Such considerations 

here do not rebut Par’s clear case of obviousness. See

Agrizap, Inc. v. Woodstream Corp., 520 F.3d 1337, 1344 

(Fed. Cir. 2008). Moreover, we do not find compelling 

Purdue’s evidence of copying in the ANDA context where 

a showing of bioequivalency is required for FDA approval. 

Nor do we find compelling Purdue’s sales figures without 

any evidence giving context to such figures. Accordingly, 

we affirm the district court’s final judgment holding the 

asserted claims of the ’887 and ’430 patents invalid as 

obvious.

Inequitable Conduct 

This court reviews the district court’s inequitable conduct determination under a two-tier standard; we review 

the underlying factual determinations for clear error but 

the ultimate decision on inequitable conduct for an abuse 

of discretion. Star Scientific, Inc. v. R.J. Reynolds Tobacco Co., 537 F.3d 1357, 1365 (Fed. Cir. 2008). A conclusion of inequitable conduct requires an accused infringer 

to show that the applicant (1) made an affirmative misrepresentation of material fact, failed to disclose material 
PURDUE PHARMA v. PAR PHARMACEUTICAL 10

information, or submitted false material information, and 

(2) did so with intent to deceive the PTO. Id. Both materiality and intent to deceive must be proven by clear and 

convincing evidence, after which the court must balance 

the equities to determine whether the conduct was egregious enough to warrant holding the entire patent unenforceable. Id.

Par argues that the district court erred in not finding 

intent to deceive because Purdue offered no credible 

explanation for withholding material experimental data 

and submitting a materially misleading declaration by 

Ms. Malkowska that reported other, more favorable, data 

to the PTO. In fact, according to Par, the district court’s 

characterization of the Malkowska declaration as an 

overly aggressive attempt to put a positive spin on the 

data is effectively a finding of deceptive intent under this 

court’s case law, citing Cargill, Inc. v. Canbra Foods, Ltd., 

476 F.3d 1359 (Fed. Cir. 2007) and Paragon Podiatry 

Laboratory, Inc. v. KLM Laboratories, Inc., 984 F.2d 1182 

(Fed. Cir. 1993). Par also asserts that the district court 

incorrectly relied on irrelevant evidence of good faith, 

including Ms. Malkowska’s failure to recall why the data 

were not submitted; the potential that the formulators did 

not recognize the data’s import to patentability when the 

evidence showed that they did; and the applicants’ later 

submission of similar data, the Napp repeat experiments. 

Purdue responds that the district court correctly 

found no intent to deceive based on the credibility of 

Purdue’s witnesses in light of the entire record, including 

that the Malkowska declaration was prepared to rebut, 

not a rejection of obviousness by the PTO, but inherent 

anticipation in an EPO proceeding, and that the applicants timely disclosed more pertinent experimental 

results, the Napp repeat experiments, generated for a 

foreign litigation. Furthermore, according to Purdue, no 
11 PURDUE PHARMA v. PAR PHARMACEUTICAL

evidence of good faith was required since Par did not meet 

its burden of showing intent to deceive, which cannot be 

inferred from materiality alone. Regardless, Purdue 

argues, the record supports a credible excuse: The omitted data did not reproduce conditions from the prior art 

and revealed dissolution rates outside those claimed in 

the asserted patents. 

We agree with Purdue and affirm the district court’s 

decision of no inequitable conduct. Even assuming that 

the applicants withheld material data and submitted a 

materially misleading declaration, as the district court 

found, Purdue Pharma, 642 F. Supp. 2d at 378, we find no 

clear error in the district court’s finding that Par failed to 

present clear and convincing evidence of intent to deceive, 

id. at 379. Specifically, the fact that the applicants later 

submitted to the PTO the Napp repeat experiments 

strongly suggests that the applicants did not act with 

deceptive intent when they omitted similar data from the 

Malkowska declaration or when they submitted the 

Malkowska declaration with its omitted data to the PTO. 

Cf. Cargill, 476 F.3d at 1366 (finding intent to deceive 

when applicants repeatedly omitted highly relevant test 

data). In fact, the Napp repeat experiments were even 

more pertinent than the withheld data as they revealed 

dissolution rates that fell directly within—rather than 

near—the claimed rates. Therefore, another reasonable 

inference is that the applicants believed (rightly or 

wrongly) that the withheld data were irrelevant, either 

because the experimental conditions did not replicate 

those of the prior art or because they did not replicate 

those in an earlier Malkowska declaration. 

Any inference of deceptive intent in the preparation of 

the declaration itself is further undermined by the fact 

that the applicants prepared the Malkowska declaration, 

not to respond directly to a rejection by the PTO, but for 
PURDUE PHARMA v. PAR PHARMACEUTICAL 12

an EPO proceeding regarding a related patent. Cf. Ferring B.V. v. Barr Labs., Inc., 437 F.3d 1181, 1193 (Fed. 

Cir. 2006); Paragon Podiatry, 984 F.2d at 1191. That 

further diminishes the reasonableness of inferring that 

any omission or misleading statement in the preparation 

of the declaration was made with the specific intent of 

deceiving the PTO. See Star Scientific, 537 F.3d at 1366. 

Because intent to deceive is not the single most reasonable inference that can be drawn from the evidence, id., 

we affirm the district court’s determination of no inequitable conduct. 

We have considered the parties remaining arguments, 

including Par’s alternative ground for affirming the 

district court’s invalidity decision, and do not find them 

persuasive. Accordingly, we affirm. 

AFFIRMED