Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-15-02030/USCOURTS-ca13-15-02030-0/pdf.json

Parties Involved:
Depomed, Inc.
Appellee
Purdue Pharma L.P.
Appellant

Document Text:

NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________ 

PURDUE PHARMA L.P.,

Appellant

v.

DEPOMED, INC.,

Appellee

______________________ 

2015-2029, 2015-2030, 2015-2032

______________________ 

Appeals from the United States Patent and Trademark Office, Patent Trial and Appeal Board in Nos. 

IPR2014-00377, IPR2014-00378, IPR2014-00379. 

______________________ 

Decided: March 24, 2016

______________________ 

GREGORY A. CASTANIAS, Jones Day, Washington, DC, 

argued for appellant. Also represented by JENNIFER 

LORAINE SWIZE; JOHN JOSEPH NORMILE, JR., GASPER 

LAROSA, LISAMARIE LOGIUDICE, New York, NY; ISRAEL

SASHA MAYERGOYZ, Chicago, IL. 

PAUL J. ANDRE, Kramer Levin Naftalis & Frankel 

LLP, Menlo Park, CA, argued for appellee. Also represented by LISA KOBIALKA, HANNAH YUNKYUNG LEE. 

______________________ 

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2 PURDUE PHARMA L.P. v. DEPOMED, INC. 

Before PROST, Chief Judge, NEWMAN and LOURIE,

Circuit Judges.

LOURIE, Circuit Judge. 

Purdue Pharma L.P. (“Purdue”) appeals from the final 

written decisions of the United States Patent and Trademark Office (“PTO”) Patent Trial and Appeal Board (“the 

Board”) affirming the patentability of all of the challenged 

claims of U.S. Patent 6,340,475 (“the ’475 patent”) and 

U.S. Patent 6,635,280 (“the ’280 patent”) in three related 

inter partes review proceedings. See Purdue Pharma L.P. 

v. Depomed, Inc., No. IPR2014-00377, 2015 WL 4150832 

(P.T.A.B. July 8, 2015) (“Purdue I”); Purdue Pharma L.P. 

v. Depomed, Inc., No. IPR2014-00378, 2015 WL 4150833 

(P.T.A.B. July 8, 2015) (“Purdue II”); Purdue Pharma L.P. 

v. Depomed, Inc., No. IPR2014-00379, 2015 WL 4150834 

(P.T.A.B. July 8, 2015) (“Purdue III”). Because the Board 

did not err in determining that Purdue, the petitioner,

failed to prove that the challenged claims are unpatentable as obvious over the cited prior art, we affirm. 

BACKGROUND

Depomed, Inc. (“Depomed”) owns the ’475 and ’280 patents, which share the same specification in relevant part, 

and are both directed to a controlled-release oral dosage 

form of a soluble drug and a method of use thereof. The 

claimed dosage form comprises a solid matrix of polymers 

with the drug dispersed therein. After dosing orally, the 

polymeric matrix swells as a result of imbibition of water 

to promote its retention in the stomach during the fed 

state, viz., in the presence of food, and remains substantially intact when the drug is released in the stomach. 

Accordingly, the claimed dosage form allows a soluble 

drug to be administered orally in a way that prolongs its

release. That prolonged release reduces the risk of transient overdosing and controls the drug dosage to safer and 

more effective levels over an extended period of time.

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PURDUE PHARMA L.P. v. DEPOMED, INC. 3

In 2013, Depomed sued Purdue in the United States 

District Court for the District of New Jersey, alleging 

infringement of the ’475 and ’280 patents. Purdue then 

filed three petitions at the PTO requesting inter partes

review of the asserted claims on grounds that those 

claims are unpatentable as, inter alia, obvious over 

Baveja et al., Zero-Order Release Hydrophilic Matrix 

Tablets of β-Adrenergic Blockers, 39 Int’l J. Pharmaceutics 

39 (1987) (“Baveja”), U.S. Patent 5,582,837 (“Shell”), and

other references. In July 2014, the Board instituted three 

separate proceedings to review the patentability of the 

following claims: (1) claims 1, 8–10, 13–15, 43, 45, and 46 

of the ’280 patent; (2) claims 1, 8–10, 13–15, 61, and 62 of 

the ’475 patent; and (3) claims 43, 54, 55, 57, 58, and 66 of 

the ’475 patent. The district court stayed the litigation

pending the Board’s review. 

Claims 1 and 43 of the ’475 patent are representative 

of the challenged claims and read as follows: 

1. A controlled-release oral drug dosage form for 

releasing a drug whose solubility in water is 

greater than one part by weight of said drug in

ten parts by weight of water, 

said dosage form comprising a solid polymeric 

matrix with said drug dispersed therein at a 

weight ratio of drug to polymer of from about 

15:85 to about 80:20, 

said polymeric matrix being one that swells 

upon imbibition of water thereby attaining a 

size large enough to promote retention in the 

stomach during said fed mode [“the swelling 

limitation”],

that releases said drug into gastric fluid by the 

dissolution and diffusion of said drug out of 

said matrix by said gastric fluid, 

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4 PURDUE PHARMA L.P. v. DEPOMED, INC. 

that upon immersion in gastric fluid retains at 

least about 40% of said drug one hour after 

such immersion and releases substantially all 

of said drug within about eight hours after 

such immersion, 

and that remains substantially intact until all 

of said drug is released [“the substantially intact limitation”].

43. A method of administering to a subject a drug 

that is therapeutic to said subject when absorbed in the stomach where said drug has at 

least one ionized group in the pH range 5 

through 8, 

said method comprising orally administering 

to said subject a dosage form of said drug 

while said subject is in a fed mode, 

said dosage form comprising a solid polymeric 

matrix with said drug dispersed therein at a 

weight ratio of drug to polymer of from about 

0.01:99.99 to about 80:20, 

said polymeric matrix being one that:

(a) swells upon imbibition of gastric fluid to a 

size large enough to promote retention in the 

stomach during said fed mode [“the swelling 

limitation”],

(b) releases said drug into gastric fluid by the 

dissolving of said drug by said gastric fluid and 

either erosion of said matrix or diffusion of 

said dissolved drug out of said matrix, 

(c) retains at least about 40% of said drug one 

hour after such immersion in gastric fluid, 

(d) releases substantially all of said drug within about ten hours after such immersion, and

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PURDUE PHARMA L.P. v. DEPOMED, INC. 5

(e) remains substantially intact until all of 

said drug is released [“the substantially intact 

limitation”],

thereby extending the release rate of said drug 

with time during said fed mode while releasing 

substantially all of said drug within said 

stomach where said drug is maintained in an 

acidic environment. 

’475 patent col. 17 ll. 45–59, col. 25 ll. 39–64.

In July 2015, after briefing and a consolidated oral 

hearing, the Board issued three final written decisions 

with similar reasoning in relevant part, in which it concluded that Purdue failed to establish by a preponderance 

of the evidence that the challenged claims would have 

been obvious over the cited prior art.1

The Board found that Baveja discloses most of the 

limitations of independent claims 1 and 43 of the ’475 and

’280 patents, except for the “swelling” and “substantially 

intact” limitations. In so finding, the Board specifically 

rejected Depomed’s argument that Baveja teaches away 

from the claimed invention. Purdue I, 2015 WL 4150832, 

at *12; Purdue II, 2015 WL 4150833, at *11; Purdue III, 

2015 WL 4150834, at *12. The Board next found that 

Shell discloses those limitations that are missing from 

Baveja. However, despite finding that the cited prior art 

teaches each limitation of claims 1 and 43 of both patents, 

Purdue I, 2015 WL 4150832, at *14, *20; Purdue II, 2015 

WL 4150833, at *13; Purdue III, 2015 WL 4150834, at 

*14, the Board found that Purdue failed to establish a 

 

1 Among the instituted grounds, the Board also 

found that Purdue failed to prove that claims 43, 54, 55, 

57, 58, and 66 of the ’475 patent were anticipated by U.S. 

Patent 6,120,803. But that finding is not at issue in this 

appeal.

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6 PURDUE PHARMA L.P. v. DEPOMED, INC. 

reason to combine the prior art to achieve the claimed 

invention with a reasonable expectation of success, Purdue I, 2015 WL 4150832, at *16, *20; Purdue II, 2015 WL 

4150833, at *15; Purdue III, 2015 WL 4150834, at *16. 

Specifically, the Board found that, although Baveja 

and Shell may have interrelated teachings, Purdue failed 

to explain persuasively “how or why” a person of ordinary 

skill in the art would have combined the “swelling” and 

“substantially intact” features of the Shell formulation 

with the Baveja formulation. Purdue I, 2015 WL 

4150832, at *16; Purdue II, 2015 WL 4150833, at *15; 

Purdue III, 2015 WL 4150834, at *16. The Board also 

found that, to the extent that Purdue relied on the nature 

of the problem to be solved to supply a reason to combine

the prior art, it improperly used hindsight by defining the 

problem with a recitation of the challenged claims. 

Moreover, the Board found that Purdue failed to establish that a skilled artisan would have had a reasonable 

expectation of success to achieve the claimed invention. 

Purdue I, 2015 WL 4150832, at *17, *20; Purdue II, 2015 

WL 4150833, at *16; Purdue III, 2015 WL 4150834, at 

*17. The Board considered expert testimony regarding

the large number of variables in play when designing a 

drug formulation, as well as co-inventor Helm’s testimony

that it took her years of research to develop the claimed 

dosage form. The Board also noted that Purdue failed to 

address why one of ordinary skill in the art would have 

reasonably expected that modifying the Baveja formulation to incorporate the “swelling” and “substantially 

intact” features would not affect the other desired properties of the Baveja formulation, such as the drug release 

profile. 

The Board therefore concluded that claims 1 and 43 of 

both patents were not shown to be unpatentable as obvious. For similar reasons, the Board concluded that Purdue failed to prove that the other challenged claims, 

which depend from either claim 1 or 43, would have been

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PURDUE PHARMA L.P. v. DEPOMED, INC. 7

obvious over the cited prior art, and therefore did not 

consider Depomed’s evidence of secondary considerations.

Purdue timely appealed to this court. We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(4)(A).

DISCUSSION

We review the Board’s legal determinations de novo, 

In re Elsner, 381 F.3d 1125, 1127 (Fed. Cir. 2004), and the 

Board’s factual findings underlying those determinations 

for substantial evidence, In re Gartside, 203 F.3d 1305, 

1316 (Fed. Cir. 2000). A finding is supported by substantial evidence if a reasonable mind might accept the evidence to support the finding. Consol. Edison Co. v. 

NLRB, 305 U.S. 197, 229 (1938).

A claim is unpatentable as obvious if the differences 

between the claimed subject matter and the prior art are 

such that the subject matter as a whole would have been 

obvious at the time of invention to a person having ordinary skill in the art. 35 U.S.C. § 103(a) (2006).2 Obviousness is a question of law premised on underlying 

issues of fact, including: (1) the scope and content of the 

prior art; (2) the level of ordinary skill in the pertinent 

art; (3) the differences between the claimed invention and 

the prior art; and (4) objective evidence, such as commercial success, long-felt need, and the failure of others. KSR 

Int’l Co. v. Teleflex Inc., 550 U.S. 398, 427 (2007); Graham 

v. John Deere Co., 383 U.S. 1, 17–18 (1966); In re Baxter, 

678 F.3d 1357, 1361 (Fed. Cir. 2012). Similarly, the 

determinations of what a reference teaches and the existence of a reason to combine references are questions of 

 

2 Because the applications leading to the ’475 and

’280 patents were filed before March 16, 2013, the preLeahy-Smith America Invents Act version of § 103 applies 

in this appeal. See Pub. L. No. 112-29, § 3(n)(1), 125 Stat. 

284, 293 (2011).

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8 PURDUE PHARMA L.P. v. DEPOMED, INC. 

fact. In re Beattie, 974 F.2d 1309, 1311 (Fed. Cir. 1992); 

In re Hyon, 679 F.3d 1363, 1365–66 (Fed. Cir. 2012). In 

an inter partes review proceeding, the petitioner bears the 

burden of proving a proposition of unpatentability by a 

preponderance of the evidence. 35 U.S.C. § 316(e).

Purdue argues that the Board erred by deviating from 

the Supreme Court’s guidance in KSR that an obviousness analysis involves an expansive and flexible approach

that accounts for the interrelated teachings of the prior 

art and the nature of the problem to be solved. Applied 

here, Purdue contends, those principles necessarily 

demonstrate how and why a skilled artisan would have 

had a reason to combine the interrelated teachings of 

Baveja and Shell, as both references teach similar controlled-release profiles of similar formulations with overlapping drug-to-polymer ratios. Purdue also argues that 

the problem to be solved provides a further reason to 

combine Baveja and Shell, for those references already 

solved the problem by teaching the drug release profile 

and other limitations of the challenged claims. Purdue 

maintains that its definition of the problem to be solved 

came directly from Shell, not from the challenged claims.

Depomed responds that the Board applied the correct 

legal standard in its obviousness analysis, recognizing

that this case involves complex and unpredictable formulation technology. According to Depomed, a skilled artisan would not have had a reason to combine Baveja and 

Shell to make the claimed dosage form. Depomed asserts

that Baveja teaches away from the non-zero-order drug 

release profiles shown in Figures 1 and 2, on which Purdue relies, by characterizing them as a “major disadvantage.” J.A. 1805. Depomed contends that Purdue’s 

generic and conclusory statements of interrelated teachings of the prior art are indicative of the fact that Purdue

presented no credible evidence on a motivation to combine 

the prior art. Depomed responds, moreover, that Purdue 

improperly relied on hindsight to formulate the problem 

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PURDUE PHARMA L.P. v. DEPOMED, INC. 9

to be solved, which cannot be derived from Shell because 

Shell focuses on drugs of limited solubility and only 

depicts drug release profiles up to seven hours.

Purdue additionally argues that Baveja and Shell 

demonstrate actual success, far more than a reasonable 

expectation of success, and that the Board overlooked the 

evidence that Baveja discloses actual dosage forms having 

the claimed drug release profiles and that Shell provides 

clear direction as to which parameters are critical. According to Purdue, the Board improperly relied on the

testimony of co-inventor Helm, who admitted that she 

was not aware of the cited references, as well as the 

testimony of Depomed’s expert Hopfenberg because that 

testimony was divorced from the explicit teachings of 

Baveja and Shell.

Depomed responds that Baveja and Shell do not establish a reasonable expectation of success, and that both 

parties’ experts testified that there were numerous variables affecting controlled-release formulations. Depomed 

argues that changing any one of those variables could 

significantly affect the drug release profile. Depomed also 

responds that Helm is more than qualified to offer testimony as one of ordinary skill in the art, and that Hopfenberg’s opinion was properly based on his review of the 

prior art. Depomed emphasizes that the claimed invention was the product of testing different combinations of 

polymers and drugs through years of research. 

We agree with Depomed that the Board applied the 

correct legal standard in its obviousness analysis and that 

substantial evidence supports its finding that Purdue 

failed to establish that a person of ordinary skill in the art 

would have had a reason to combine Baveja and Shell to 

pursue the claimed invention with a reasonable expectation of success. As the petitioner before the Board in an 

inter partes review proceeding, Purdue bore the burden of 

establishing obviousness of the challenged claims by a 

preponderance of the evidence. 35 U.S.C. § 316(e). The

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10 PURDUE PHARMA L.P. v. DEPOMED, INC. 

Board did not err in finding that Purdue failed to satisfy 

that burden.

The record shows that the Board correctly determined 

that each limitation of the challenged independent claims 

was known in the art, as evidenced by the teachings of 

Baveja and Shell. In particular, the Board correctly found 

that Baveja teaches almost all of the limitations of claims 

1 and 43 of the ’475 and ’280 patents, and that Shell 

teaches the “swelling” and “substantially intact” limitations not otherwise disclosed in Baveja.

Moreover, substantial evidence supports the Board’s 

finding that Baveja does not teach away from the claimed 

dosage form. Although Baveja expresses a preference for

oral dosage forms that exhibit a zero-order release profile 

over those that do not, that preference does not amount to 

teaching away from dosages forms with a non-zero-order 

release profile. See In re Mouttet, 686 F.3d 1322, 1334 

(Fed. Cir. 2012) (“[J]ust because better alternatives exist 

in the prior art does not mean that an inferior combination is inapt for obviousness purposes.”). 

Nevertheless, the Board correctly recognized that “a 

patent . . . is not proved obvious merely by demonstrating 

that each of its elements was, independently, known in 

the prior art.” KSR, 550 U.S. at 418. Indeed, it remains 

“important to identify a reason that would have prompted 

a person of ordinary skill in the relevant field to combine 

the elements in the way the claimed new invention does.” 

Id. (emphases added). As the Board correctly recognized, 

one may look to “interrelated teachings” of multiple 

references, id., or a “problem known in the field of endeavor,” id. at 420, to determine whether there was an 

“apparent reason” to combine the prior art teachings “in 

the fashion claimed by the patent at issue,” id. at 418. 

Although the obviousness analysis may not be confined by any formalistic test, or by overemphasis on the 

explicit teachings of prior art publications, a petitioner 

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PURDUE PHARMA L.P. v. DEPOMED, INC. 11

must nevertheless make a sufficient showing that is more 

than “mere conclusory statements,” to establish a reason 

that would have prompted a skilled artisan to combine 

the prior art teachings in the way of the claimed invention. Id. at 418–19. As we have explained, a patent 

challenger must demonstrate that a skilled artisan would 

have had reason to combine the teachings of the prior art 

references to achieve the claimed invention, and that the 

skilled artisan would have had a reasonable expectation 

of success from doing so. See PAR Pharm., Inc. v. TWI 

Pharm., Inc., 773 F.3d 1186, 1193 (Fed. Cir. 2014).

Here, the Board found that Purdue failed to sufficiently show that a skilled artisan would have had a reason to 

combine the teachings of Baveja and Shell to achieve the 

claimed invention. That determination is supported by 

substantial evidence, which we must uphold, rather than 

revisit de novo. The record shows that Purdue presented

limited evidence of a reason to combine the teachings of 

Baveja and Shell. E.g., J.A. 1956–62, 1985–86 (¶¶ 127–

28, 131–33, 193–94); Appellant’s Br. 38–39. Its expert 

opined generally on the interrelated teachings of those 

references, but did not explain in sufficient detail how or 

why a skilled artisan would have been motivated to 

combine the “swelling” and “substantially intact” features 

of the Shell formulation with the Baveja formulation to 

attain the claimed dosage form. 

Moreover, to the extent that Purdue relies on the 

problem to be solved to supply the reason to combine the 

prior art, it failed to demonstrate to the Board that the 

problem was known in the art or that Purdue’s formulation of the problem was derived directly from the prior 

art, rather than from the challenged claims. The Board 

therefore did not err in finding that Purdue improperly 

relied on hindsight in formulating the problem to be 

solved. Insite Vision Inc. v. Sandoz, Inc., 783 F.3d 853, 

859 (Fed. Cir. 2015) (“Defining the problem in terms of its 

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12 PURDUE PHARMA L.P. v. DEPOMED, INC. 

solution reveals improper hindsight in the selection of the 

prior art relevant to obviousness.”).

We also conclude that substantial evidence supports 

the Board’s finding that Purdue failed to sufficiently show 

that a skilled artisan would have had a reasonable expectation of success in combining Baveja and Shell to achieve 

the claimed dosage form. As the Board noted, both parties’ experts testified on the large number of formulation 

considerations in play when designing a drug formulation. 

In light of that, Purdue did not sufficiently explain why a 

skilled artisan would have expected that the Baveja 

formulation could be modified to incorporate the “swelling” and “substantially intact” features of Shell, without 

affecting the other desired properties. In other words, 

Purdue did not address whether adding the “swelling” 

and “substantially intact” features to the Baveja formulation would have been reasonably expected to lead to a 

dosage form that satisfies the other limitations of the 

challenged claims.

Accordingly, we conclude that the Board did not err in 

finding that Purdue failed to establish a reason to combine the cited prior art to achieve the claimed invention 

with a reasonable expectation of success. Because the 

Board did not reach the merits of Depomed’s evidence of 

secondary considerations, we similarly decline to do so in 

the first instance on appeal.

CONCLUSION

We have considered the remaining arguments, but 

find them to be unpersuasive. The Board did not err in 

determining that Purdue failed to make a sufficient 

showing that the challenged claims of the ’475 and ’280 

patents would have been obvious over the cited prior art. 

We therefore affirm the Board’s decision. 

AFFIRMED

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