Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-23-01953/USCOURTS-ca13-23-01953-0/pdf.json

Parties Involved:
Accord Healthcare, Inc.
Appellee
Purdue Pharma L.P.
Appellant
Purdue Pharmaceuticals L.P.
Appellant
Rhodes Technologies
Appellant

Document Text:

NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________

PURDUE PHARMA L.P., PURDUE 

PHARMACEUTICALS L.P., RHODES 

TECHNOLOGIES,

Plaintiffs-Appellants

v.

ACCORD HEALTHCARE, INC.,

Defendant-Appellee

______________________

2023-1953

______________________

Appeal from the United States District Court for the 

District of Delaware in No. 1:20-cv-01362-RGA, Judge 

Richard G. Andrews.

______________________

Decided: December 30, 2024

______________________

GREGORY G. GARRE, Latham & Watkins LLP, Washington, DC, argued for plaintiffs-appellants. Also represented 

by ALEXANDER GEORGE SIEMERS, MARGARET UPSHAW; 

DANIEL BROWN, New York, NY; DAVID KOWALSKI, San Diego, CA; GREGORY A. CASTANIAS, JENNIFER L. SWIZE, Jones 

Day, Washington, DC; GASPER LAROSA, JOHN JOSEPH 

NORMILE, JR., New York, NY; PABLO DANIEL HENDLER, Potomac Law Group PLLC, New York, NY.

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2 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

 BEN MAHON, McAndrews, Held & Malloy, Ltd., Chicago, IL, argued for defendant-appellee. Also represented 

by BRADLEY P. LOREN, ALEJANDRO MENCHACA.

______________________

Before PROST, REYNA, and TARANTO, Circuit Judges.

PROST, Circuit Judge.

Purdue Pharma L.P., Purdue Pharmaceuticals L.P., 

and Rhodes Technologies (collectively, “Purdue”) appeal 

from the final judgment of the U.S. District Court for the 

District of Delaware, which held all asserted claims of the 

five challenged patents invalid as obvious under 35 U.S.C. 

§ 103. Purdue Pharma L.P. v. Accord Healthcare, Inc., 669 

F. Supp. 3d 286 (D. Del. 2023). We affirm. 

BACKGROUND

I

This case involves patents related to Purdue’s formulation of extended-release oxycodone, sold as Oxycontin. Oxycodone was first developed in the 1910s. J.A. 1822. In the 

1990s, Purdue developed an extended-release formulation, 

approved by the FDA in 1995. Appellants’ Br. 5. “Unfortunately, oxycodone has become one of the most frequently 

abused prescription medications and some formulations 

can be dissolved and injected intravenously.” Oxycodone, 

https://www.ncbi.nlm.nih.gov/books/NBK547955/#:~:text=

Oxycodone; Appellants’ Br. 1 (“The original [OxyContin] 

tablets could easily be crushed and then snorted or injected 

to produce an immediate high, causing severe risks of addiction, overdose, and death.”). Additionally, the process of 

creating oxycodone hydrocholoride, “a well-known molecule [that] has been synthesized for decades,” Appellee’s 

Br. 4 (citing J.A. 5066–67), results in the creation of 14-hydroxy. 14-hydroxy, an alpha beta unsaturated ketone 

(“ABUK”), is “a potentially genotoxic (i.e., carcinogenic) 

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PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC. 3

impurity.” Appellants’ Br. 2. In other words, oxycodone is 

often abused and may be genotoxic when consumed in large 

quantities.

The asserted patents in this case attempt to address 

these two problems. The first group of patents—U.S. Patent Nos. 9,763,933 (“the Mannion ’933 patent”), 9,775,808 

(“the ’808 patent”), and 9,763,886 (“the ’886 patent”) (collectively, “the Abuse-Deterrent Patents”)—are directed to 

a crush-resistant formulation of OxyContin, “mak[ing] it 

hard enough to resist crushing and viscous enough to deter 

intravenous users.” Purdue Pharma, 669 F. Supp. 3d 

at 292. These two qualities help to minimize some of the 

more common methods of abusing OxyContin. The second 

group of asserted patents—U.S. Patent Nos. 9,073,933 

(“the ’933 patent”) and 9,522,919 (“the ’919 patent”) (collectively, “the Low-ABUK Patents”)—are directed to a formulation and process of reducing 14-hydroxy in OxyContin, 

thereby reducing toxicity concerns. Each group of patents 

is discussed in more detail below.

A

The Abuse-Deterrent Patents, which share a common 

specification, claim a “formulation of oxycodone using the 

polymer polyethylene oxide (‘PEO’).” Appellants’ Br. 1. 

Claim 3 of the ’808 patent, which depends from claim 1, is 

illustrative. Together they recite:

1. A pharmaceutical composition comprising:

at least one active agent comprising oxycodone or a 

pharmaceutically acceptable salt thereof;

at least one high molecular weight polyethylene oxide (PEO), having an approximate molecular 

weight of from 1 million to 15 million;

at least one of an additive and a film coating; and

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4 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

optionally at least one low molecular weight PEO 

having an approximate molecular weight of less 

than 1,000,000; wherein

(a) the active agent and high molecular weight 

PEO are combined in a solid oral extended release 

dosage form that is (i) compression shaped, (ii) air 

cured by heated air, without compression, for at 

least about 5 minutes at a temperature above the 

softening temperature of the high molecular 

weight PEO, (iii) cooled, and (iv) hardened;

(b) the high molecular weight PEO comprises at 

least about 30% (by weight) of the dosage form;

(c) the molecular weight of each PEO is based on 

rheological measurements; and

(d) the total weight of the dosage form is calculated 

by excluding the combined weight of said film coatings.

Id. at claim 1.

3. A pharmaceutical composition according to claim 

1, wherein the curing temperature is from about 

70° C. to about 85° C. and the curing time is from 

about 10 minutes to about 10 hours.

Id. at claim 3.

Relevant to this appeal is the curing method recited in 

these claims. The curing method has four general steps: 

(1) “the tablet must be ‘compression shaped,’” e.g., id.

at claim 1; (2) the tablet “must be ‘air cured by heated air, 

without compression,’” e.g., id.; (3) “the heating must be 

done for ‘about 10 minutes to about 10 hours,’” e.g., id.

at claim 3; and (4) “the heating must be done above the softening temperature of PEO and at about 70–85° C or 

65–90° C,” Mannion ’933 patent claim 3; ’808 patent 

claim 3; ’886 patent claim 6. See Appellants’ Br. 7–8. “This 

process produces a hardened tablet resistant to crushing, 

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but also capable of dissolving and relieving pain over an 

extended period of time.” Id. at 11. Purdue identifies two 

alleged points of novelty: (1) “[N]o one had ever cured PEO 

tablets using heated air without simultaneous compression 

or at the times and temperatures”—i.e., the claims here require the alleged novel concept of compression then heating. And (2) the recited process had the “surprising 

benefit” of “decreas[ing] . . . tablet density that promoted 

faster gelling.” Id. Allegedly, this faster gelling makes it 

more difficult to abuse the oxycodone tablets because the 

drug becomes gelatinous in the nasal cavity (making it 

harder to ingest) and making it hard to expel through a 

syringe. Id. at 11–12. 

B

The Low-ABUK Patents, which share a common specification, address a different problem: reducing the potential of genotoxicity from the molecule 14-hydroxy created 

during the manufacturing of oxycodone. “The synthesis 

process involves three steps: (1) oxidation of thebaine to 

form 14-hydroxy; (2) hydrogenation of 14-hydroxy to form 

oxycodone; and (3) addition of hydrochloric acid to form a 

salt.” Appellee’s Br. 4–5; see also Appellants’ Br. 16. 

By the early 2000s, the FDA had grown concerned 

about this potential toxicity and began requesting that 

drug manufactures reduce 14-hydroxy in their oxycodone 

products. To reduce 14-hydroxy levels, Purdue first attempted to ensure that the hydrogenation step was run to 

completion—i.e., ensuring “all detectable 14-hydroxy was 

converted to oxycodone base.” Appellants’ Br. 16. But this 

did not solve the problem. During the third step of the process, 14-hydroxy would reform in the drug. Through further research, Dr. Kupper, listed as an inventor on the 

Low-ABUK Patents, identified another impurity in oxycodone, known as 8α. Id. at 17. The Low-ABUK Patents explain that 8α is converted to 14-hydroxy under acidic 

conditions, such as salt formation, which explains why 

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6 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

residual 14-hydroxy was reappearing in the third manufacturing step. It is undisputed that “[t]he Low ABUK Patents were the first to report the presence of the molecule 

8α in the synthesis of oxycodone.” Appellee’s Br. 5; see also

Appellants’ Br. 17 (“Dr. Kupper . . . discover[ed] a previously unknown impurity called 8α.”).

Relevant to this appeal are the low levels of 14-hydroxy 

and the 8α limitations. The asserted Low-ABUK Patent 

claims have slight differences among them regarding the 

amount of 14-hydroxy and 8α recited. For example, claim 3

of the ’933 patent, which depends from claim 1, recites:

1. An oxycodone hydrochloride composition which 

comprises at least 95% oxycodone hydrochloride, 

8α, 14-dihydroxy-7, 8-dihydrocodeinone, and less 

than 25 ppm of 14-hydroxycodeinone.

Id. at claim 1.

3. The oxycodone hydrochloride composition of 

claim 1, having less than 10 ppm of 14-hydroxycodeinone.

Id. at claim 3. 

Claim 11 of the ’933 patent, which depends from 

claim 10, recites “removing 8α” from the composition, and 

claim 21 of the ’919 patent recites a specific ratio involving 

8α and 14-hydroxy in the composition: “the ratio of 8α, 14-

dihydroxy-7, 8-dihydrocodeinone to oxycodone HCl is 

0.04% or less.” 

II

In 2010, Purdue developed, and the FDA approved, a 

new formulation of OxyContin. Four out of the five 

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asserted patents are listed in the FDA’s Orange Book as 

purportedly covering this reformulation.1 

In August 2020, Accord Healthcare, Inc. (“Accord”) submitted an Abbreviated New Drug Application (“ANDA”) for 

approval to market a generic version of OxyContin. Purdue

then filed suit in October 2020, asserting that Accord had 

infringed, among others, the Mannion ’933 patent, the

’808 patent, the ’886 patent, the ’933 patent, and the 

’919 patent through the act of filing the ANDA. See 35 

U.S.C. § 271(e)(2)(A). Accord stipulated to infringement, 

and the district court held a three-day bench trial in September 2021 on the sole issue of invalidity. The claims at 

issue were claim 3 of the Mannion ’933 patent, claim 3 of 

the ’808 patent, claim 6 of the ’886 patent, claims 3 and 11 

of the ’933 patent, and claim 21 of the ’919 patent. The 

court held all asserted claims were invalid as obvious. 

As to the Abuse-Deterrent Patents, Accord argued that 

the asserted claims were obvious in view of five references:

Bartholomaus,2 McGinity,3 and three other references referred to as “Oven Art.”4 “Bartholomaus and McGinity 

1 “The Mannion ’933, ’808, ’933, and ’919 patents are

all listed in the FDA’s Orange Book for OxyContin. The 

’886 patent is not.” Purdue Pharma, 669 F. Supp. 3d 

at 293.

2 U.S. Patent Publication No. 2005/0031546 (“Bartholomaus”), J.A. 9417–30.

3 U.S. Patent No. 6,488,963 (“McGinity”), 

J.A. 9408–16.

4 Zezhi J. Shao et al., Effects of Formulation Variables and Post-compression Curing on Drug Release from a 

New Sustained-Release Matrix Material: PolyvinylacetatePovidone, 6 Pharm. Dev. and Tech. 2, 257 (2001) (“Shao”), 

J.A. 9431–38; Nashiru Billa et al., Diclofenac Release from 

Eudragit-Containing Matrices and Effects of Thermal 

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8 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

broadly teach PEO matrix tablets formed with simultaneous compression and heating. The three Oven Art references broadly teach curing non-PEO matrix tablets in 

ovens after compression.” Purdue Pharma, 669 F. Supp. 

3d at 297. The district court summarized the dispute as 

follows:

The parties disagree about whether a [person of ordinary skill in the art] would have been motivated 

to make PEO tablets with sequential compression 

and heating, and whether there would have been a 

reasonable expectation of success in doing so. Second, no prior art used the same combinations of 

curing time and temperature ranges as those disclosed in the Abuse-Deterrent Patents. The parties 

disagree about whether routine experimentation 

by a [person of ordinary skill in the art] would have 

yielded the times and temperatures disclosed in 

the patents.

Id. (internal citations omitted).

As to the first dispute (i.e., sequential compression and 

heating), the district court agreed with Accord that a person of ordinary skill in the art would be motivated “to modify Bartholomaus and McGinity because the processes 

disclosed in those references would not have been suitable 

for large-scale production,” and a person of ordinary skill 

in the art would have “naturally turn[ed] to ovens in either 

scaling up Bartholomaus or adapting McGinity to more 

commonly available equipment.” Id. at 297–98. The

Treatment, 24 Drug Dev. and Indus. Pharm. 1, 45–50 

(1998), J.A. 9439–45; Marcelo O. Omelczuk & James W. 

McGinity, The Influence of Thermal Treatment on the Physical-Mechanical Properties of Tablets Containing Poly(DLLactic Acid), 10 Pharm. Rsch. 4, 542 (1992) (“Omelczuk”), 

J.A. 9446–96.

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district court also found that a person of ordinary skill in 

the art would have had a reasonable expectation of success 

in producing hardened tablets with sequential compression 

and then heating the tablets. As to the second dispute (the 

times and temperatures for curing tablets), the district 

court again agreed with Accord, based on expert testimony, 

that the times and temperatures recited in the patents’

claims would have been the “product of routine experimentation.” Id. at 303. The court also considered Purdue’s alleged secondary considerations and concluded that they do 

not weigh in favor of nonobviousness. Therefore, the district court concluded that the Abuse-Deterrent Patents 

would have been invalid as obvious over the prior art. Id.

at 306. 

As to the Low-ABUK Patents, “the parties’ disputes 

[fell] into two categories: the obviousness of low levels of 

14-hydroxy and the obviousness of the inventors’ discovery 

of 8α.” Id. at 312. The district court concluded that a person of ordinary skill in the art would have been motivated 

to lower 14-hydroxy levels based on FDA communications 

suggesting that it might require lower ABUK levels in the 

future and that such person would have had a reasonable 

expectation of success in doing so based on routine experimentation. Id. at 313–17. With respect to the 8α limitations, the court addressed the parties’ arguments on a 

limitation-by-limitation basis. For claim 3 of the ’933 patent, the claim recited only the existence of 8α in the composition, and because Purdue did not dispute 8α would be 

present, the court found this inherent property would have 

been obvious and that “the identification of 8α itself was 

merely routine.” Id. at 318. With respect to claim 11 of 

the ’933 patent (reciting “removing 8α”) and claim 21 of the 

’919 patent (reciting a specific ratio of 8α), the court agreed 

with Accord’s unrebutted expert testimony that a person of 

ordinary skill in the art “would be able to monitor the levels 

of 8α in order to reduce the ratio of 8α to oxycodone,” and 

given that a person of ordinary skill in the art “would have 

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10 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

been able to routinely identify 8α or [a related impurity] 8β

as the source of extra 14-hydroxy, . . . removing 8α, either 

directly or by removing 8β—is also obvious.” Id. at 320. 

The court therefore concluded that the Low-ABUK Patents’ 

asserted claims would have been obvious.

Purdue timely appealed. We have jurisdiction under 

28 U.S.C. § 1295(a)(1).

DISCUSSION 

“Obviousness is a question of law, reviewed de novo, 

based upon underlying factual questions which are reviewed for clear error following a bench trial.” Aventis 

Pharma Deutschland GmbH v. Lupin, Ltd., 499 F.3d 1293, 

1300 (Fed. Cir. 2007) (cleaned up). “The presence or absence of a motivation to arrive at the claimed invention, 

and of a reasonable expectation of success in doing so, are 

questions of fact.” Amgen Inc. v. Sandoz Inc., 66 F.4th 952, 

960 (Fed. Cir. 2023). “A factual finding is only clearly erroneous if, despite some supporting evidence, we are left 

with the definite and firm conviction that a mistake has 

been made.” Merck Sharp & Dohme Corp. v. Hospira, Inc., 

874 F.3d 724, 728 (Fed. Cir. 2017) (citations omitted).

“A patent for a claimed invention may not be obtained

. . . if the differences between the claimed invention and the 

prior art are such that the claimed invention as a whole 

would have been obvious before the effective filing date of 

the claimed invention . . . .” 35 U.S.C. § 103. “Obviousness 

is based on underlying factual findings, including: (1) the 

level of ordinary skill in the art; (2) the scope and content 

of the prior art; (3) the differences between the claims and 

the prior art; and (4) secondary considerations of nonobviousness, such as commercial success, long-felt but unmet 

needs, failure of others, and unexpected results.” Prometheus Labs., Inc. v. Roxane Labs., Inc., 805 F.3d 1092, 1097 

(Fed. Cir. 2015) (citing KSR Int’l Co. v. Teleflex, Inc., 550 

U.S. 398, 406 (2007); Graham v. John Deere Co., 383 U.S. 

1, 17–18 (1966)). 

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Purdue appeals the district court’s obviousness conclusions regarding both the Abuse-Deterrent Patents and the 

Low-ABUK Patents. We address each set of patents, and 

the alleged district court errors identified by Purdue, in 

turn. 

I

For the Abuse-Deterrent Patents, Purdue argues that 

the district court erred in (A) finding a motivation to combine with a reasonable expectation of success and (B) dismissing Purdue’s arguments related to secondary 

considerations. We disagree.

A 

Purdue raises a litany of arguments related to motivation to combine and reasonable expectation of success: that 

the district court (1) failed to consider the claims as a 

whole; (2) made improper “inferential leaps” by focusing 

solely on oven tools without addressing the effect of heating 

tablets without compression; (3) improperly invoked KSR’s 

obvious-to-try rationale; (4) “applied the wrong legal standard” with respect to reasonable expectation of success; 

(5) erred by relying on “a general discussion” in the prior 

art to support its conclusion that compressing, then heating, would have been obvious; and (6) erred by relying on 

“routine experimentation” to find that the time and temperature limitations of the Abuse-Deterrent Patent claims 

would have been obvious. The first of these arguments is 

not directed to a specific limitation in the claims; the next 

four arguments are directed to whether a person of ordinary skill would have found it obvious to compress and 

then heat the tablets (as recited by the claims) rather than 

simultaneously compression and heating; and the last argument is directed at the various time and temperature requirements for curing a tablet as recited in the claims. 

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12 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

1

We start with Purdue’s argument that the district 

court erred by failing to analyze the claims as a whole. 

Sanofi-Synthelabo v. Apotex, Inc., 550 F.3d 1075, 1086 

(Fed. Cir. 2008) (“The determination of obviousness is 

made with respect to the subject matter as a whole, not 

separate pieces of the claim.”). The requirement to address 

“claims as a whole” has normally been invoked when a tribunal has ignored elements of the claims, looked solely to 

the inventive aspects of the claims, or erred by failing to 

address specific (rather than generalized) claim limitations. See, e.g., Para-Ordnance Mfg., Inc. v. SGS Importers 

Int’l, Inc., 73 F.3d 1085, 1087 (Fed. Cir. 1995) (“[T]he 

claimed invention should be considered as a whole; there is 

no legally recognizable ‘heart’ of the invention.”).

The district court did not make such an error here. 

Purdue’s argument essentially relies on a single footnote in 

the district court’s opinion as the basis for asserting a legal 

error. The footnote states:

This issue relates to both of the differences between 

the claims and the prior art noted previously. I discuss whether the experimentation would be routine 

when discussing the second difference of time and 

temperature ranges. For the purposes of reasonable expectation of success, I only ask whether a 

[person of ordinary skill in the art] could reasonably expect to make hardened tablets by combining 

Bartholomaus and McGinity at the claimed times 

and temperatures. 

Purdue Pharma, 669 F. Supp. 3d at 301 n.5. The footnote 

appears during a discussion of reasonable expectation of 

success of the “sequential compression and heating” limitations. Purdue reads this footnote as “analyz[ing] the 

claim limitations in isolation—looking initially (1) to 

whether the change from simultaneous to sequential compression and heating would have been obvious; and then 

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separately (2) to whether the time and temperature parameters for the applicable process would have been obvious as 

discoverable through routine experimentation.” Appellants’ Br. 32.

We read this footnote as clarifying the specific issues 

the district court discussed at that portion of its opinion. 

As a practical matter, a court must normally address one 

issue at a time, and in patent cases, it is the norm for both 

parties and courts to discuss disputed claim limitations sequentially. Purdue’s argument is particularly unpersuasive because, despite this footnote, the court substantively 

discussed the “time and temperature” limitations while analyzing the parties’ arguments directed to the “sequential 

compression and heating” limitations. See Purdue 

Pharma, 669 F. Supp. 3d at 302 (discussing “how generally 

to find optimal ranges,” the reasonable expectation of success in achieving those ranges, and the application of common sense in conjunction with the Oven Art in finding that 

“heating times in ovens might be longer”). Therefore, we 

disagree that the court erred by failing to address the 

claims as a whole.5

2

Next, Purdue argues that the district court made an 

improper “inferential leap” in determining that a person of 

ordinary skill in the art would have been motivated to 

5 Purdue similarly argues that the court erred in its 

reasonable-expectation-of-success analysis based on alleged “piecemeal analysis.” Appellants’ Br. 42 (“[T]he district court ignored the relevant time and temperature 

parameters entirely.”). This argument fails for the same 

reasons articulated here—the court did in fact address the 

claims as a whole. It thoroughly addressed the “time and 

temperature” limitations, even in discussing the “sequential compression and heating” limitations. 

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14 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

combine Bartholomaus and McGinity with the Oven Art

when the court said, “[i]t is not much of a leap to infer that 

ovens would also be useful for applying heat to harden the 

matrix tablets.” Id. at 300. 

The court relied on multiple factual findings that all 

support the conclusion that it would have been obvious to 

try ovens for heating tablets. For example, Accord presented expert testimony on the availability of ovens and

the prior use of ovens to heat tablets (including matrix tablets made from several different polymers), and “Shao specifically taught that the heat curing made its tablets 

harder.” Id. at 299–300. “Plaintiffs’ witnesses did not provide any testimony to the contrary.” Id. at 299. Thus, Purdue’s claims that the court relied on a “naked inference” is 

unsupported by the record. Appellants’ Br. 34.

3 

Purdue next argues that the district court legally erred 

by invoking KSR’s obvious-to-try test when it concluded 

that “employing a commonly available tool [i.e., ovens] to 

apply heat to tablets is obvious to try.” Id. at 36 (quoting 

Purdue Pharma, 669 F. Supp. 3d at 300). KSR explained 

that a particular combination of elements may be obvious 

to try “[w]hen there is a design need or market pressure to 

solve a problem and there are a finite number of identified, 

predictable solutions.” 550 U.S. at 421. Purdue argues 

that the district court ran afoul of this standard because it 

“made no finding that there were a finite number of predictable solutions, and the record plainly shows the opposite.” Appellants’ Br. 36. We again disagree.

To set the stage for this argument, Purdue frames the 

problem to be solved as “abuse by crushing” and identifies 

several possible solutions to opioid abuse unrelated to 

physically hardening tablets. Id. at 36–40 (listing antagonists, aversive agents, and covalently-bound inactive moieties). In contrast, Accord frames the problem to be solved 

as a scalable process for heating PEO with a finite number 

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of possible solutions: ovens, pan coaters, and fluid bed dryers. Appellee’s Br. 21. We disagree with Purdue’s framing 

of the problem to be solved that underlies the motivation to 

combine Bartholomaus and McGinity with the Oven Art at 

least because it ignores what was already known and 

taught in the prior art. 

As Purdue recognizes, KSR involved a situation, where 

“there were only a very small number of possible locations 

for attaching the pedal sensor at issue because the prior art 

already taught the need to place it on a fixed, non-moving 

point on the pedal.” Appellants’ Br. 36. Baked into this 

characterization is the recognition that KSR was focused 

on why a person of ordinary skill would be motivated to 

address certain problems in view of the prior art. Indeed, 

the Court’s detailed description of the prior art and its application in the obvious-to-try rationale supports the notion 

that the problem to be solved (and the possible solutions) 

should take into consideration the advancements and 

teachings already in the prior art. See KSR, 550 U.S. 

at 424–25 (“For a designer starting with Asano [a prior-art 

reference], the question was where to attach the sensor. 

The consequent legal question, then, is whether a pedal designer of ordinary skill starting with Asano would have 

found it obvious to put the sensor on a fixed pivot point. 

The prior art discussed above leads us to the conclusion 

that attaching the sensor where both KSR and [the inventor] put it would have been obvious to a person of ordinary 

skill.”). KSR did not abstract back out to the larger problem (e.g., designing an adjustable pedal having an electronic sensor) and ask how many different ways that could 

be done (e.g., redesigning the whole car), completely disconnected from where the prior art would have already led 

a person of ordinary skill in the art. 

Similarly, here, Bartholomaus and McGinity already 

taught making hardened tablets, including PEO antiabuse tablets with compression and heating. We therefore 

conclude that Accord’s and the district court’s framing of 

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16 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

the problem—scalability of hardened tablets—is more apt 

here. See Appellee’s Br. 21; Purdue Pharma, 669 F. Supp. 

3d at 297 (“[A] [person of ordinary skill in the art] would 

then seek to modify Bartholomaus and McGinity because 

the processes disclosed in those references would not have 

been suitable for large-scale production.”). To address this 

problem, Accord’s expert testified “that ovens were commonly available and used to heat tablets.” Purdue 

Pharma, 669 F. Supp. 3d at 299. As explained above, 

“Plaintiffs’ witnesses did not provide any testimony to the 

contrary.” Id. In other words, the court based its conclusion on unrebutted expert testimony and “the absence of 

testimony about other heating tools.” Id. at 300. In this

absence, the court was presented with a finite number of 

solutions to the problem of scalability for creating antiabuse tablets with compression and heating. On this record, the court’s reliance on the obvious-to-try rationale was 

a natural choice. 

Because we reject the premise that the problem to be 

solved here is general “abuse deterrence,” and Purdue’s entire argument was based on this framing of the problem, 

we reject Purdue’s argument that the district court erred 

as a matter of law. 

4

Next, Purdue argues that the court “applied the wrong 

legal standard” with respect to reasonable expectation of 

success by asking whether a person of ordinary skill in the 

art “might” or “could” have reasonably expected success instead of asking whether a person of ordinary skill in the art 

“would” have reasonably expected success. Appellants’ 

Br. 41. We disagree that the court applied the wrong 

standard.

While the district court did use the words “could” and 

“might” when discussing the reasonable expectation of success in some circumstances, Purdue takes these isolated 

uses of “could” and “might” out of context. For example, at 

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PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC. 17

least two instances of the use of “could” were based on a 

framing of what Purdue argued—not what question the 

court was addressing. Purdue Pharma, 669 F. Supp. 3d 

at 301 (“Plaintiffs argue that there could not have been a 

reasonable expectation of success . . . .”); id. (“They argue 

that . . . a [person of ordinary skill in the art] could not have 

reasonably expected success.”); cf. id. at 302 (“I was not persuaded, based on [Purdue’s expert] testimony . . . that a 

[person of ordinary skill in the art] could not still reasonably expect . . . .”). 

Regardless, the court made numerous findings about 

what a person of ordinary skill in the art “would” have reasonably expected. See id. at 300 (“I consider whether a 

[person of ordinary skill in the art] would have had a ‘reasonable expectation of success’ . . . .”); id. at 301 (“I think 

there is a reasonable expectation of success . . . .” (emphasis 

added)); id. (“a [person of ordinary skill in the art] would 

expect . . . to be able to achieve . . .” (emphasis added)); id.

at 302 (“I find there was clear and convincing evidence that 

a [person of ordinary skill in the art] would reasonably expect . . .” (emphasis added)). These findings and conclusions demonstrate that the court applied the correct legal 

standard and support the court’s conclusion that a person 

of ordinary skill in the art “would reasonably expect to produce hardened tablets by heating PEO tablets to their 

melting points in an oven.” Id. A few references as to what 

“could” be expected does not necessarily indicate the court 

legally erred. For example, in Belden Inc. v. Berk-Tek LLC, 

even where the Patent Trial and Appeal Board (“Board”) 

twice opined on what “could” have been done, we still concluded that the Board’s findings were sufficient because 

the Board “did not stop there” but additionally made findings as to what the prior art taught and what a person of 

ordinary skill in the art “would have recognized.” 805 F.3d 

1064, 1073–74 (Fed. Cir. 2015). The same is true here. 

Read in context, we conclude that the court did not apply the incorrect legal standard.

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18 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

5

Next, Purdue argues that the district court erred by relying on “a general discussion” in the prior art to support 

its conclusion that a person of ordinary skill in the art 

would have had a reasonable expectation of success of compressing and then heating the tablets. We disagree.

It is undisputed that Bartholomaus teaches crush-resistant PEO tablets. Purdue Pharma, 669 F. Supp. 3d 

at 299 (agreeing that Batholomaus and McGinity “each . . .

discloses an effective crush-resistant tablet”). And Bartholomaus explains that “[t]he solid, abuse-proofed dosage 

form according to the invention is preferably produced by 

mixing the components (A), (B), and (C) and/optionally (D) 

and at least one of the optionally present further abusepreventing components (a)-(f) and, optionally after granulation, press-forming the resultant mixture to yield the dosage form with preceding, simultaneous, or subsequent 

exposure to heat.” J.A. 9423, [0065]; see also id. at [0067]. 

Before the district court, Accord argued that this passage 

supported a finding of reasonable expectation of success; 

Purdue disagreed arguing that this passage was “generic.” 

Purdue Pharma, 669 F. Supp. 3d at 301. The court agreed 

that the statement was “generic” but nonetheless found it 

“sufficient to support a [person of ordinary skill in the art]’s 

expectations.” Id.

The court did not clearly err in finding that the Bartholomaus passage supports a reasonable expectation of 

success. The passage refers to (1) mixing various components, including component (C), which the patent identifies 

as optionally PEO, J.A. 9420, [0018]; (2) press-forming the 

mixture (i.e. compressing); and (3) “preceding, simultaneous, or subsequent exposure to heat.” J.A. 9423, [0065].

This disclosure, whether generic or not, discusses a procedure for creating hardened tablets, incorporating PEO, and 

recites an option for compression and subsequent heating—i.e., it identifies a method of tablet production that 

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PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC. 19

mirrors the disputed limitations. We see no clear error in 

the court’s reliance on this passage, as well as numerous 

other findings supported by expert testimony, to support 

the conclusion that “there is a reasonable expectation of 

success in producing a hardened tablet from sequential 

compression and then heating of PEO.” Purdue Pharma, 

669 F. Supp. 3d at 301. 

6

Finally, Purdue argues that the court erred by relying

on the doctrine of “routine experimentation” to find that 

the time and temperature limitations of the Abuse-Deterrent claims would have been obvious. “Where the general 

conditions of a claim are disclosed in the prior art, it is not 

inventive to discover the optimum or workable ranges by 

routine experimentation.” In re Applied Materials, Inc., 

692 F.3d 1289, 1295 (Fed. Cir. 2012) (cleaned up). Purdue 

argues that here the prior art did not teach “the general 

conditions”; Accord argues just the opposite. 

The district court relied on the following evidence to 

conclude that the general conditions surrounding the time 

and temperature ranges were taught in the prior art:

Of the three asserted claims, two claim curing temperatures of 70° C to 85° C, while the third claims 

65° C to 90° C. All three claim heating times from 

ten minutes to ten hours. The times taught in Shao 

overlap with the time ranges in the patents, but 

Shao does not use PEO. The temperatures in Bartholomaus and Omelczuk are consistent with those 

in the asserted claims, but Bartholomaus teaches 

shorter and Omelczuk longer heating times. Because McGinity teaches melting the PEO, its temperatures are also consistent with those in the 

patent. 

Purdue Pharma, 669 F. Supp. 3d at 302 (internal citations 

omitted); see also J.A. 9427 (Bartholomaus teaching 

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20 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

heating PEO to 80° C); J.A. 9416 (McGinity teaching heating “at a temperature range of about 75° C. to 130° C. . . . 

so that melting or softening of the PEO occurred”); J.A. 

9432 (Shao teaching heating of non-PEO tables in an oven 

at 60° C “for varying lengths of time ranging from 10 

minutes to 18 h”). The court considered the claims and 

found that the prior art taught general conditions that 

overlap with the claim limitations. Again, we see no clear 

error in the court’s findings. Thus, we do not agree with 

Purdue that reliance on “routine experimentation” in these 

circumstances was a legal error.

B

We now turn to Purdue’s argument that the court erred 

in its treatment of the alleged secondary considerations of 

nonobviousness. “[Secondary considerations] must always 

when present be considered in the overall obviousness 

analysis. But they do not necessarily control the obviousness determination. Indeed, a strong showing of obviousness may stand even in the face of considerable evidence of 

[secondary considerations].” Adapt Pharma Operations 

Ltd. v. Teva Pharms. USA, Inc., 25 F.4th 1354, 1372 (Fed. 

Cir. 2022) (cleaned up). “The evidence of secondary considerations must have a nexus to the claims, i.e., there must 

be a legally and factually sufficient connection between the 

evidence and the patented invention. The patentee bears 

the burden of showing that a nexus exists. To determine 

whether the patentee has met that burden, we consider the 

correspondence between the objective evidence and the 

claim scope.” Fox Factory, Inc. v. SRAM, LLC, 944 

F.3d 1366, 1373 (Fed. Cir. 2019) (cleaned up).

Purdue alleges that the district court committed two 

legal errors. First, Purdue argues that the court “asked 

only whether the secondary considerations ‘undermine’ an 

existing finding of obviousness.” Appellants’ Br. 47. In 

Adapt Pharma, the plaintiffs argued that the “district 

court committed legal error because, according to 

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PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC. 21

[plaintiffs], it concluded that the asserted claims would 

have been obvious before considering [plaintiffs’] evidence 

of [secondary considerations].” 25 F.4th at 1372. This argument is substantively identical to Purdue’s first alleged 

legal error. And as in Adapt Pharma, “[w]e are not persuaded.” Id. “[I]t is evident from the district court’s opinion that it considered all of the evidence on the issue of 

obviousness, including the [secondary considerations], in 

coming to its ultimate legal conclusion. Although the district court’s analysis of the [secondary considerations] in 

the opinion follows its discussion of the prima facie case of 

obviousness, there is nothing inherently wrong with that.” 

Id. Nor does the use of the word “undermine” in the district 

court’s opinion persuade us that this case is different from 

Adapt Pharma, particularly in light of KSR’s analogous 

phrasing—secondary considerations did not “dislodge the 

determination [of] . . . obvious[ness].” 550 U.S. at 426 (emphasis added). 

Second, Purdue argues that the district court “misevaluated—and improperly dismissed—each [secondary consideration] separately.” Appellants’ Br. 48. Below, we 

address each of the secondary considerations that Purdue 

raises—commercial success, skepticism, failure of others, 

and unexpected results. 

1

Purdue argues that “reformulated OxyContin—with 

abuse deterrent qualities—has had commercial success” 

and that “detailed evidence establish[es] a nexus between 

OxyContin’s commercial success and its abuse-deterrent 

features.” Id. at 48–49. Specifically, Purdue argues that 

“after Purdue reformulated OxyContin, [the] FDA concluded that original OxyContin was withdrawn from the 

market because of safety concerns related to its abuse.

[The] FDA also prohibited all non-abuse-deterrent extended-release oxycodone products . . . .” Id. at 49 (internal 

citations omitted). 

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22 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

We see no clear error in the court’s finding that Purdue 

failed to “prove[] commercial success due to the claimed 

features of the invention.” Purdue Pharma, 669 F. Supp. 

3d at 305. Here, expert testimony confirmed “that the new 

formulation replaced the original formulation, with all 

sales transferred to the new formulation.” Id. And the 

court found that “there was no demonstrated increase in 

the success of OxyContin relative to other opioids when the 

patented features were introduced.” Id. Simply stated, the 

court found no nexus between the claimed invention and 

the commercial success. Bald assertions of commercial success unconnected to the patented features of the claimed 

invention are not given patentable weight. See, e.g., Pentec, Inc. v. Graphic Controls Corp., 776 F.2d 309, 316 (Fed. 

Cir. 1985) (“Because GC was clearly the market leader well 

before the introduction of the [claimed invention], its sales 

figures cannot be given controlling weight in determining 

the effect of commercial success in this case on the question 

of obviousness.”).

2

Purdue next turns to industry skepticism as a purported secondary consideration. Specifically, Purdue argues that the FDA was skeptical about “applying an abusedeterrent label until they had seen how [reformulated OxyContin] functioned in the real world and if it really did 

deter abuse.” Appellants’ Br. 53 (quoting J.A. 5709). Purdue alleges that the court excluded the FDA’s skepticism 

from the weight of secondary considerations because the 

FDA “is not in the industry.” Id. (citing Purdue Pharma, 

669 F. Supp. 3d at 306). 

We disagree that the court disregarded Purdue’s argument simply because the FDA is not in the industry. The 

court merely noted that the FDA is not in the industry but 

weighed the evidence regardless:

[T]he FDA, which is not in the industry, displayed 

an amount of skepticism commensurate with the 

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PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC. 23

fact that this was the first extended-release opioid 

to receive abuse-deterrent labelling. It seems natural that the FDA, as a regulatory body, would require real world studies before being satisfied that 

a hard tablet was indeed abuse-deterrent.

Purdue Pharma, 669 F. Supp. 3d at 306. Moreover, as Accord notes, the FDA’s skepticism was about applying the 

abuse-deterrent label, not about the creation (even at large 

scale) and utility of the claimed product. The asserted patents “contain[] no limitations requiring any level of abuse 

deterrence.” Appellee’s Br. 39. For these reasons, we see 

no clear error in the court’s conclusion that “Plaintiffs have 

[not] proven industry skepticism by a preponderance of the 

evidence.” Purdue Pharma, 669 F. Supp. 3d at 306. 

3

With respect to the failure of others, Purdue identifies 

two products whose producers failed to “develop[] a successful abuse-deterrent formulation”—Develco and Opana. 

Appellants’ Br. 54–55.

With respect to Develco, the court found that “the production failures of Develco seem to weigh in favor of the 

production-scale-based motivation to combine . . . rather 

than in favor of the nonobviousness of the patents.” Purdue Pharma, 669 F. Supp. 3d at 306. With respect to 

Opana, the court found that “the record is not clear on why 

Opana was removed from the market,” and “[Purdue] did 

not establish by a preponderance of the evidence that 

Opana’s removal was related to its lack of ‘the claimed features.’” Id. With respect to both Develco and Opana, “the 

evidence does not suggest [on this record] that these prior 

attempts failed because the [formulation] lacked the 

claimed features.” Ormco Corp. v. Align Tech., Inc., 463 

F.3d 1299, 1313 (Fed. Cir. 2006). In other words, the court 

again concluded that Purdue had not established a nexus 

between the alleged secondary consideration and the 

claimed invention. Based on these findings, “[w]e are not 

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24 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

left with a definite and firm conviction that the district 

court erred in this regard. We thus see no clear error in 

the district court’s finding that this evidence is not significantly probative of nonobviousness.” Adapt Pharma, 25 

F.4th at 1376.

4

Finally, with respect to unexpected results, Purdue argues that “the district court agreed that the claimed invention exhibited an unexpected property by decreasing tablet 

density—which Purdue’s expert testified could enhance 

abuse deterrence by causing the tablet to gel more quickly 

if crushed.” Appellants’ Br. 57. But, according to Purdue, 

the court erred by “declining to afford [unexpected results] 

any weight.” Id. We disagree. 

In fact, the court found that Purdue “ha[d] established 

by a preponderance of the evidence the existence of unexpected results.” Purdue Pharma, 669 F. Supp. 3d at 304. 

But these unexpected results did “not alone undermine the 

clear and convincing evidence that the invention’s claimed 

properties [would have been] obvious.” Id.; see also W. Union Co. v. MoneyGram Payment Sys., Inc., 626 F.3d 1361, 

1371 (Fed. Cir. 2010) (“[W]eak secondary considerations 

generally do not overcome a strong prima facie case of obviousness.”). We see no reversible error in this overall assessment. 

For the reasons above, we affirm the court’s holding 

that claim 3 of the Mannion ’933 patent, claim 3 of the 

’808 patent, and claim 6 of the ’886 patent are invalid.

II

Turning to the Low-ABUK Patents, Purdue first advances two sweeping legal principles: (1) “[w]here the problem is unknown, there can be no reasonable expectation of 

success in solving it”; and (2) “an invention is non-obvious 

where the inventor discovers ‘the source’ of a problem.” Appellants’ Br. 59. Applying these principles, Purdue 

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contends that the Low-ABUK Patents are nonobvious because Purdue discovered the “previously unknown problem” that 14-hydroxy reappeared after its removal during 

the synthesis of oxycodone, and it discovered the source of 

the problem, the impurity 8α. Id. at 60. 

With respect to the alleged discovery of an unknown 

problem, Purdue’s argument necessarily fails because the 

problem was known. Specifically, the district court found 

that “testimony at trial . . . indicated that an understanding or suspicion that ABUKs were toxic existed even before 

September 2002.” Purdue Pharma, 669 F. Supp. 3d at 315.

While Purdue attempts to suggest a narrower problem 

statement—i.e., 14-hydroxy reappeared after its removal 

during the synthesis of oxycodone—this effectively transforms Purdue’s argument from an alleged legal error to an 

alleged factual error. And on the factual point, the court 

agreed with Accord that “a [person of ordinary skill in the 

art] would have two clear starting points: either adding a 

final hydrogenation step to remove 14-hydroxy hydrochloride or attempting to remove 14-hydroxy at an earlier 

stage.” Id. Even between these two starting points, the 

district court considered the parties’ arguments, reviewed 

the expert testimony, and concluded that Accord had “presented clear and convincing argument that a [person of ordinary skill in the art] would try to intervene at an earlier 

stage of the oxycodone synthesis to ensure that all 14-hydroxy was converted to oxycodone prior to salt formation. I 

am also persuaded that a [person of ordinary skill in the 

art] would have the knowledge and skill to do so successfully.” Id. at 316. We see no clear error in the court’s factual findings on this record. 

Regarding discovery of “the source” of a problem, even 

Eibel Process Co. v. Minnesota & Ontario Paper Co., upon 

which Purdue heavily relies, demonstrates that obviousness is based upon underlying factual questions. See 261 

U.S. 45, 52 (1923) (“The issue is one largely of evidence.”). 

“In Eibel Process, the invention was a machine that could 

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26 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

make quality paper at high speeds. At the time, papermaking machines could not operate at high speeds without 

producing wrinkled paper. Eibel discovered that the unequal speeds of paper stock and a wire in the machine produced the wrinkled paper. . . . The Supreme Court upheld 

the validity of Eibel’s patent, reasoning that the discovery 

of the problem—unequal speeds of paper stock and the 

wire—was nonobvious, and thus the solution was as well.” 

Purdue Pharma L.P. v. Epic Pharma, LLC, 811 F.3d 1345, 

1352 (Fed. Cir. 2016). But even in concluding that the patent was nonobvious, the Court laid out different factual 

scenarios that may have led to a different conclusion:

Had the trouble which Eibel sought to remedy been 

the well-known difficulty of too great wetness or 

dryness of the web at the dandy roll, and had he 

found that a higher rather than a lower pitch would 

do that work better, a patent for this improvement 

might well have been attacked on the ground that 

he was seeking monopoly for a mere matter of degree. But that is not this case. On the other hand, 

if all knew that the source of the trouble Eibel was 

seeking to remedy was where he found it to be, and 

also knew that increased speed of the stock would 

remedy it, doubtless it would not have been invention on his part to use the pitch of the wire to increase the speed of the stock, when such pitch had 

been used before to do the same thing, although for 

a different purpose and in less degree.

Eibel Process, 261 U.S. at 68.

Between Eibel’s discussion of different factual scenarios and KSR’s warning to avoid “[r]igid preventative rules 

that deny factfinders recourse to common sense,” we believe the proper inquiry here is one of fact. In other words, 

even recognizing that Purdue may have discovered 8α, we 

disagree that, “[t]hat should have ended the inquiry.” Appellants’ Br. 61. Therefore, we turn to the two alleged

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factual flaws that Purdue identified—i.e., the court’s reliance on inherency and routine experimentation. 

“[I]nherency may supply a missing claim limitation in 

an obviousness analysis.” PAR Pharm., Inc. v. TWI 

Pharms., Inc., 773 F.3d 1186, 1194–95 (Fed. Cir. 2014). “It 

is long settled that in the context of obviousness, the ‘mere 

recitation of a newly discovered function or property, inherently possessed by things in the prior art, does not distinguish a claim drawn to those things from the prior art.’” 

Persion Pharms. LLC v. Alvogen Malta Operations Ltd., 

945 F.3d 1184, 1190 (Fed. Cir. 2019) (citation omitted). 

Purdue relies on Honeywell International Inc. v. Mexichem 

Amanco Holding S.A. de C.V., 865 F.3d 1348 (Fed. Cir. 

2017), for the proposition that, “that which ‘may be inherent is not necessarily known’ and that which is unknown 

cannot be obvious.’” Appellants’ Br. 62 (quoting Honeywell, 

865 F.3d at 1354). But Honeywell does not help Purdue 

because it was a case about motivation to combine. See 

Cytiva BioProcess R&D AB v. JSR Corp., 122 F.4th 876,

890 (Fed. Cir. 2024). In Honeywell, the claimed invention 

was a composition that comprised two components. Both 

components were disfavored in the art for the claimed purpose, but the combination of the two components had unexpected properties. In this circumstance, even though the 

unexpected properties were inherent, “a person of ordinary 

skill in the art would not have been motivated to combine 

the two compounds in the first place.” Id. Thus, Honeywell 

is not applicable here. 

Instead, we turn to each of the asserted Low-ABUK Patent claims individually, as the district court did, because 

the disputed limitations in each claim are slightly different. First, “[c]laim 3 of the ’933 patent requires only that 

8α be present in the composition.” Purdue Pharm., 669 F. 

Supp. 3d at 318 (citing ’933 patent claim 3). The court concluded that claim 3 was obvious because 8α was inherently 

present in the prior art compositions. Indeed, “Plaintiffs 

d[id] not dispute that 8α was present in prior art 

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28 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

compositions.” Id. In other words, like in Cytiva (where 

we found the claims unpatentable based on an undisputedly inherent property), Purdue attempts to claim an inherent part of the composition—8α. Because this

limitation was undisputedly present in the prior art, nothing more is needed because there is no “difference[] between the claimed invention and the prior art.” 35 U.S.C. 

§ 103.

Second, claim 21 of the ’919 patent recites a different 

limitation with respect to 8α—“the ratio of 8α,14-dihydroxy-7,8-dihydrocodeinone to oxycodone HCl is 0.04% or 

less, ’919 patent claim 18 (from which claim 21 depends); 

and claim 11 of the ’933 patent recites “removing 8α,14-dihydroxy-7,8-dihydrocodeinone”, ’933 patent claim 10 (from 

which claim 11 depends). Here, the court relied on a sequence of facts to arrive at the conclusion that both limitations would have been obvious to a person of ordinary skill 

in the art conducting routine experimentation. Purdue 

Pharm., 669 F. Supp. 3d at 315–20. On appeal, Plaintiffs 

contend it was improper for the court to rely on routine experimentation because “routine experimentation applies

only where the claimed invention merely identifies the ‘optimum or workable ranges’ of previously disclosed conditions.” See Appellants’ Br. 63 (citing E.I. DuPont de 

Nemours & Co. v. Synvina C.V., 904 F.3d 996, 1006 (Fed. 

Cir. 2018)) (emphasis added). We are unaware of such a 

brightline rule. For example, in Merck, we agreed that it 

was “reasonable for the district court to deduce from the 

evidence that the order and detail of the steps, if not already known, would have been discovered by routine experimentation while implementing known principles.”

Merck, 874 F.3d at 730. The disputed limitations there 

were not only “optimum or workable ranges” but included

“the order of the steps, the simultaneous addition of base, 

the specific temperature range, and a final moisture content of less than 10%.” Id. 

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Similarly, here, the court “looked to testimony provided 

by both sides’ experts” and was “persuade[d] . . . that a 

[person of ordinary skill in the art] would have quickly postulated and easily confirmed the existence of 8α.” Purdue 

Pharm., 669 F. Supp. 3d at 319. Purdue only makes two 

factual arguments that allegedly undermine the court’s 

finding of routine experimentation—i.e., that the court ignored Noramco’s attempt to develop Low-ABUK oxycodone

and that the court acknowledged “routine experimentation 

with early removal of 14-hydroxy ‘would not immediately 

succeed.’” Appellants’ Br. 63. As to Noramco, the court did 

not ignore this evidence. See Purdue Pharm., 669 F. Supp. 

3d at 317. The court simply did not find it “sufficient” to 

overcome Accord’s expert testimony. Purdue fails to explain why the court erred in finding Noramco’s failure insufficient in light of the expert testimony, and we see no 

clear error in the court’s analysis on this point. As to Purdue’s argument that a person of ordinary skill in the art 

“would not immediately succeed” in early removal of 14-hydroxy, we are not aware of a test for routine experimentation that requires a person of ordinary skill in the art to 

“immediately succeed.” Absent an argument why the district’s analysis was clear error, we conclude it was “reasonable for the district court to deduce from the evidence that 

the [disputed claim limitations] . . . would have been discovered by routine experimentation while implementing 

known principles.” Merck, 874 F.3d at 730. 

Having confirmed that the district court did not err in 

its determination that routine experimentation would lead 

a person of ordinary skill to “quickly postulate[] and easily 

confirm[] the existence of 8α,” and because the remainder

of the court’s analysis with respect to claim 21 of the 

’919 patent and claim 11 of the ’933 patent is not contested, 

we affirm the district court’s holding that the challenged 

claims of the Low-ABUK Patents would have been obvious. 

See Purdue Pharm., 669 F. Supp. 3d at 319–20. 

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30 PURDUE PHARMA L.P. v. ACCORD HEALTHCARE, INC.

CONCLUSION

We have considered Purdue’s remaining arguments 

and find them unpersuasive. For the foregoing reasons, we 

affirm the district court’s final judgment, holding claim 3 

of the Mannion ’933 patent, claim 3 of the ’808 patent, 

claim 6 of the ’886 patent, claims 3 and 11 of the ’933 patent, and claim 21 of the ’919 patent invalid as obvious under 35 U.S.C. § 103.

AFFIRMED

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