Purdue Pharma L.p., Purdue Pharmaceuticals L.p., Rhodes Technologies v. Accord Healthcare, Inc.

N OTE: This disposition is nonprecedential.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
______________________
G REGORY G. G ARRE , Latham & Watkins LLP, Washing-
ton, DC, argued for plaintiffs-appellants. Also represented
by ALEXANDER G EORGE SIEMERS , MARGARET U PSHAW ;
D ANIEL BROWN, New York, NY; D AVID K OWALSKI, San Di-
ego, CA; G REGORY A. CASTANIAS , J ENNIFER L. SWIZE, Jones
Day, Washington, DC; G ASPER L AROSA, J OHN J OSEPH
N ORMILE, J R., New York, NY; P ABLO D ANIEL HENDLER , Po-
tomac Law Group PLLC, New York, NY.
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 2
BEN MAHON, McAndrews, Held & Malloy, Ltd., Chi-
cago, IL, argued for defendant-appellee. Also represented
by BRADLEY P. L OREN , ALEJANDRO M ENCHACA .
______________________
Before P ROST , REYNA, and T ARANTO, Circuit Judges.
P ROST , 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 formula-
tion of extended-release oxycodone, sold as Oxycontin. Ox-
ycodone 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. “Unfor-
tunately, 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 ad-
diction, overdose, and death.”). Additionally, the process of
creating oxycodone hydrocholoride, “a well-known mole-
cule [that] has been synthesized for decades,” Appellee’s
Br. 4 (citing J.A. 5066–67), results in the creation of 14-hy-
droxy. 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. Pa-
tent Nos. 9,763,933 (“the Mannion ’933 patent”), 9,775,808
(“the ’808 patent”), and 9,763,886 (“the ’886 patent”) (col-
lectively, “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”) (collec-
tively, “the Low-ABUK Patents”)—are directed to a formu-
lation 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 ox-
ide (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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 4
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 coat-
ings.
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 sof-
tening 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 5
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 re-
quire the alleged novel concept of compression then heat-
ing. 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 speci-
fication, address a different problem: reducing the poten-
tial 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 at-
tempted 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 pro-
cess, 14-hydroxy would reform in the drug. Through fur-
ther research, Dr. Kupper, listed as an inventor on the
Low-ABUK Patents, identified another impurity in oxyco-
done, known as 8α. Id. at 17. The Low-ABUK Patents ex-
plain that 8α is converted to 14-hydroxy under acidic
conditions, such as salt formation, which explains why
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 6
residual 14-hydroxy was reappearing in the third manufac-
turing step. It is undisputed that “[t]he Low ABUK Pa-
tents 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 previ-
ously 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-hydroxyco-
deinone.
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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 7
asserted patents are listed in the FDA’s Orange Book as
purportedly covering this reformulation.1
In August 2020, Accord Healthcare, Inc. (“Accord”) sub-
mitted 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 Sep-
tember 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 re-
ferred 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 (“Bar-
tholomaus”), 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 Varia-
bles and Post-compression Curing on Drug Release from a
New Sustained-Release Matrix Material: Polyvinylacetate-
Povidone, 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 8
broadly teach PEO matrix tablets formed with simultane-
ous compression and heating. The three Oven Art refer-
ences 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 or-
dinary 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. Sec-
ond, no prior art used the same combinations of
curing time and temperature ranges as those dis-
closed 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 per-
son of ordinary skill in the art would be motivated “to mod-
ify 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 Phys-
ical-Mechanical Properties of Tablets Containing Poly(DL-
Lactic Acid), 10 Pharm. Rsch. 4, 542 (1992) (“Omelczuk”),
J.A. 9446–96.
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 9
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 experimen-
tation.” Id. at 303. The court also considered Purdue’s al-
leged secondary considerations and concluded that they do
not weigh in favor of nonobviousness. Therefore, the dis-
trict 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 per-
son 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 experi-
mentation. Id. at 313–17. With respect to the 8α limita-
tions, the court addressed the parties’ arguments on a
limitation-by-limitation basis. For claim 3 of the ’933 pa-
tent, the claim recited only the existence of 8α in the com-
position, 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 10
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).
D ISCUSSION
“Obviousness is a question of law, reviewed de novo,
based upon underlying factual questions which are re-
viewed 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 ab-
sence 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 er-
roneous 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 nonobvi-
ousness, such as commercial success, long-felt but unmet
needs, failure of others, and unexpected results.” Prome-
theus 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 PHARMA L . P. v. ACCORD HEALTHCARE, INC. 11
Purdue appeals the district court’s obviousness conclu-
sions 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 com-
bine with a reasonable expectation of success and (B) dis-
missing Purdue’s arguments related to secondary
considerations. We disagree.
A
Purdue raises a litany of arguments related to motiva-
tion 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 stand-
ard” 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 heat-
ing, would have been obvious; and (6) erred by relying on
“routine experimentation” to find that the time and tem-
perature 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 ordi-
nary 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 ar-
gument is directed at the various time and temperature re-
quirements for curing a tablet as recited in the claims.
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 12
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 tri-
bunal 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 limita-
tions. 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 dis-
cuss whether the experimentation would be routine
when discussing the second difference of time and
temperature ranges. For the purposes of reasona-
ble expectation of success, I only ask whether a
[person of ordinary skill in the art] could reasona-
bly 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” limi-
tations. Purdue reads this footnote as “analyz[ing] the
claim limitations in isolation—looking initially (1) to
whether the change from simultaneous to sequential com-
pression and heating would have been obvious; and then
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 13
separately (2) to whether the time and temperature param-
eters for the applicable process would have been obvious as
discoverable through routine experimentation.” Appel-
lants’ 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 se-
quentially. Purdue’s argument is particularly unpersua-
sive because, despite this footnote, the court substantively
discussed the “time and temperature” limitations while an-
alyzing 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 suc-
cess in achieving those ranges, and the application of com-
mon 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 al-
leged “piecemeal analysis.” Appellants’ Br. 42 (“[T]he dis-
trict 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 “sequen-
tial compression and heating” limitations.
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 14
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 pre-
sented expert testimony on the availability of ovens and
the prior use of ovens to heat tablets (including matrix tab-
lets made from several different polymers), and “Shao spe-
cifically taught that the heat curing made its tablets
harder.” Id. at 299–300. “Plaintiffs’ witnesses did not pro-
vide any testimony to the contrary.” Id. at 299. Thus, Pur-
due’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 pre-
dictable solutions, and the record plainly shows the oppo-
site.” 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 antago-
nists, aversive agents, and covalently-bound inactive moi-
eties). In contrast, Accord frames the problem to be solved
as a scalable process for heating PEO with a finite number
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 15
of possible solutions: ovens, pan coaters, and fluid bed dry-
ers. 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 ap-
plication 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 de-
signer 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 inven-
tor] put it would have been obvious to a person of ordinary
skill.”). KSR did not abstract back out to the larger prob-
lem (e.g., designing an adjustable pedal having an elec-
tronic sensor) and ask how many different ways that could
be done (e.g., redesigning the whole car), completely dis-
connected 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 anti-
abuse tablets with compression and heating. We therefore
conclude that Accord’s and the district court’s framing of
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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 com-
monly 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 conclu-
sion 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 anti-
abuse tablets with compression and heating. On this rec-
ord, 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 en-
tire 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 in-
stead 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 suc-
cess 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 per-
suaded, based on [Purdue’s expert] testimony . . . that a
[person of ordinary skill in the art] could not still reasona-
bly expect . . . .”).
Regardless, the court made numerous findings about
what a person of ordinary skill in the art “would” have rea-
sonably expected. See id. at 300 (“I consider whether a
[person of ordinary skill in the art] would have had a ‘rea-
sonable 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 ex-
pect . . .” (emphasis added)). These findings and conclu-
sions 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 pro-
duce 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 con-
cluded that the Board’s findings were sufficient because
the Board “did not stop there” but additionally made find-
ings 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 ap-
ply the incorrect legal standard.
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5
Next, Purdue argues that the district court erred by re-
lying 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 com-
pressing and then heating the tablets. We disagree.
It is undisputed that Bartholomaus teaches crush-re-
sistant PEO tablets. Purdue Pharma, 669 F. Supp. 3d
at 299 (agreeing that Batholomaus and McGinity “each . . .
discloses an effective crush-resistant tablet”). And Bar-
tholomaus 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 abuse-
preventing components (a)-(f) and, optionally after granu-
lation, press-forming the resultant mixture to yield the dos-
age 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 Bar-
tholomaus passage supports a reasonable expectation of
success. The passage refers to (1) mixing various compo-
nents, 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, simultane-
ous, or subsequent exposure to heat.” J.A. 9423, [0065].
This disclosure, whether generic or not, discusses a proce-
dure for creating hardened tablets, incorporating PEO, and
recites an option for compression and subsequent heat-
ing—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-Deter-
rent 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 tem-
peratures 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 Bar-
tholomaus and Omelczuk are consistent with those
in the asserted claims, but Bartholomaus teaches
shorter and Omelczuk longer heating times. Be-
cause McGinity teaches melting the PEO, its tem-
peratures 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 20
heating PEO to 80° C); J.A. 9416 (McGinity teaching heat-
ing “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 obvious-
ness determination. Indeed, a strong showing of obvious-
ness 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 consid-
erations 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 ar-
gument is substantively identical to Purdue’s first alleged
legal error. And as in Adapt Pharma, “[w]e are not per-
suaded.” Id. “[I]t is evident from the district court’s opin-
ion 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 dis-
trict 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 (em-
phasis added).
Second, Purdue argues that the district court “miseval-
uated—and improperly dismissed—each [secondary con-
sideration] 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 con-
cluded that original OxyContin was withdrawn from the
market because of safety concerns related to its abuse.
[The] FDA also prohibited all non-abuse-deterrent ex-
tended-release oxycodone products . . . .” Id. at 49 (internal
citations omitted).
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 22
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 suc-
cess unconnected to the patented features of the claimed
invention are not given patentable weight. See, e.g., Pen-
tec, 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 pur-
ported secondary consideration. Specifically, Purdue ar-
gues that the FDA was skeptical about “applying an abuse-
deterrent label until they had seen how [reformulated Ox-
yContin] functioned in the real world and if it really did
deter abuse.” Appellants’ Br. 53 (quoting J.A. 5709). Pur-
due 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 argu-
ment 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 nat-
ural that the FDA, as a regulatory body, would re-
quire real world studies before being satisfied that
a hard tablet was indeed abuse-deterrent.
Purdue Pharma, 669 F. Supp. 3d at 306. Moreover, as Ac-
cord 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 pa-
tents “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 suc-
cessful abuse-deterrent formulation”—Develco and Opana.
Appellants’ Br. 54–55.
With respect to Develco, the court found that “the pro-
duction 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.” Pur-
due 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 fea-
tures.’” 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 24
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 signifi-
cantly probative of nonobviousness.” Adapt Pharma, 25
F.4th at 1376.
4
Finally, with respect to unexpected results, Purdue ar-
gues that “the district court agreed that the claimed inven-
tion 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 unex-
pected 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. Un-
ion 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 ob-
viousness.”). We see no reversible error in this overall as-
sessment.
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 ad-
vances two sweeping legal principles: (1) “[w]here the prob-
lem 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.” Ap-
pellants’ Br. 59. Applying these principles, Purdue
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 25
contends that the Low-ABUK Patents are nonobvious be-
cause Purdue discovered the “previously unknown prob-
lem” 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 understand-
ing 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 trans-
forms 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 hydrochlo-
ride 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 “pre-
sented clear and convincing argument that a [person of or-
dinary skill in the art] would try to intervene at an earlier
stage of the oxycodone synthesis to ensure that all 14-hy-
droxy 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 success-
fully.” Id. at 316. We see no clear error in the court’s fac-
tual 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 obvious-
ness 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 26
make quality paper at high speeds. At the time, paper-
making machines could not operate at high speeds without
producing wrinkled paper. Eibel discovered that the une-
qual speeds of paper stock and a wire in the machine pro-
duced 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 pa-
tent 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 de-
gree. 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 inven-
tion on his part to use the pitch of the wire to in-
crease 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 scenar-
ios and KSR’s warning to avoid “[r]igid preventative rules
that deny factfinders recourse to common sense,” we be-
lieve 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.” Ap-
pellants’ Br. 61. Therefore, we turn to the two alleged
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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 27
factual flaws that Purdue identified—i.e., the court’s reli-
ance 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, inher-
ently possessed by things in the prior art, does not distin-
guish 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 inher-
ent 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 pur-
pose, but the combination of the two components had un-
expected 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 Pa-
tent claims individually, as the district court did, because
the disputed limitations in each claim are slightly differ-
ent. 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 con-
cluded 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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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 28
compositions.” Id. In other words, like in Cytiva (where
we found the claims unpatentable based on an undisput-
edly inherent property), Purdue attempts to claim an in-
herent part of the composition—8α. Because this
limitation was undisputedly present in the prior art, noth-
ing more is needed because there is no “difference[] be-
tween 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-dihy-
droxy-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-di-
hydroxy-7,8-dihydrocodeinone”, ’933 patent claim 10 (from
which claim 11 depends). Here, the court relied on a se-
quence of facts to arrive at the conclusion that both limita-
tions 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 ex-
perimentation because “routine experimentation applies
only where the claimed invention merely identifies the ‘op-
timum or workable ranges’ of previously disclosed condi-
tions.” 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 al-
ready known, would have been discovered by routine ex-
perimentation 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 con-
tent 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 pos-
tulated 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 ig-
nored 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 ex-
plain why the court erred in finding Noramco’s failure in-
sufficient in light of the expert testimony, and we see no
clear error in the court’s analysis on this point. As to Pur-
due’s argument that a person of ordinary skill in the art
“would not immediately succeed” in early removal of 14-hy-
droxy, we are not aware of a test for routine experimenta-
tion that requires a person of ordinary skill in the art to
“immediately succeed.” Absent an argument why the dis-
trict’s analysis was clear error, we conclude it was “reason-
able for the district court to deduce from the evidence that
the [disputed claim limitations] . . . would have been dis-
covered 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.
Case: 23-1953 Document: 43 Page: 29 Filed: 12/30/2024

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PURDUE PHARMA L . P. v. ACCORD HEALTHCARE, INC. 30
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 pa-
tent, and claim 21 of the ’919 patent invalid as obvious un-
der 35 U.S.C. § 103.
AFFIRMED
Case: 23-1953 Document: 43 Page: 30 Filed: 12/30/2024

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