United States Court of Appeals 

for the Federal Circuit ______________________ 

TEVA PHARMACEUTICALS USA, INC.,

Appellant

v.

CORCEPT THERAPEUTICS, INC.,

Appellee

______________________ 

2021-1360

______________________ 

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. PGR2019-

00048.

______________________ 

Decided: December 7, 2021 

______________________ 

JOHN CHRISTOPHER ROZENDAAL, Sterne Kessler Goldstein & Fox, PLLC, Washington, DC, argued for appellant. 

Also represented by UMA EVERETT, WILLIAM MILLIKEN,

OLGA A. PARTINGTON, DEBORAH STERLING. 

 ERIC C. STOPS, Quinn Emanuel Urquhart & Sullivan, 

LLP, New York, NY, argued for appellee. Also represented 

by WILLIAM ADAMS, FRANK CHARLES CALVOSA, FRANCIS 

DOMINIC CERRITO, DANIEL C. WIESNER. 

 ______________________ 

Case: 21-1360 Document: 34 Page: 1 Filed: 12/07/2021
2 TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 

Before MOORE, Chief Judge, NEWMAN and REYNA, Circuit 

Judges.

MOORE, Chief Judge. 

In a final-written decision, the Patent Trial and Appeal 

Board held that Teva Pharmaceuticals USA had failed to 

show claims 1–13 of U.S. Patent No. 10,195,214 would have 

been obvious. Teva Pharms. USA, Inc. v. Corcept Therapeutics, Inc., PGR2019-00048, 2020 WL 6809812 (P.T.A.B. 

Nov. 18, 2020) (Final Decision). Teva appeals, arguing the 

Board misapplied our obviousness law.1 For the following 

reasons, we affirm.

I 

A 

In the 1980s, mifepristone was developed as an antiprogestin. See J.A. 1009. But researchers soon realized 

mifepristone functions as a glucocorticoid reception antagonist, meaning it likely inhibits the effect of cortisol on tissues by competing with cortisol for receptor binding sites. 

See J.A. 870, 1037. As a result, they suggested using mifepristone to treat Cushing’s syndrome, a disease caused by 

excessive levels of cortisol. J.A. 1034–38. 

More than 20 years later, Corcept Therapeutics, Inc., 

initiated the first major clinical trial of mifepristone in patients with Cushing’s syndrome. J.A. 1252. Over a 24-

week period, 50 participants were given one daily dose of 

mifepristone, starting at a dosage of 300 mg per day and 

possibly increasing to a maximum dosage of 1200 mg per 

day. J.A. 1259. That administration “produced significant 

clinical and metabolic improvement in patients with 

[Cushing’s syndrome] with an acceptable risk-benefit 

1 Teva also argues that, under the correct standards, 

the challenged claims would have been obvious. Because 

we discern no legal error, we need not reach that argument.

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TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 3

profile during 6 months of treatment.” J.A. 1259; accord 

J.A. 1259–61. 

Based on its successful study, Corcept filed a New Drug 

Application (NDA) for Korlym, a 300 mg mifepristone tablet. It sought approval for the administration of Korlym to

control “hyperglycemia secondary to hypercortisolism” in 

certain patients with Cushing’s syndrome. J.A. 982. The 

U.S. Food and Drug Administration approved Corcept’s application, but imposed a few postmarketing requirements 

under 21 U.S.C. § 355(o)(3). One requirement was to conduct “[a] drug-drug interaction clinical trial to determine a 

quantitative estimate of the change in exposure of mifepristone following co-administration of ketoconazole (a 

strong CYP3A4 inhibitor).” J.A. 984. 

To summarize the drug-drug interaction study requirement, the FDA provided Corcept with an Office of Clinical 

Pharmacology memorandum. See J.A. 865–900 (hereinafter, Lee). That memorandum explained that “[t]he degree 

of change in exposure of mifepristone when co-administered with strong CYP3A inhibitors is unknown . . . .” 

J.A. 865. Thus, Lee noted that co-administration “may present a safety risk” and that, without a drug-drug interaction study, a “lack of accurate knowledge” may “deprive the 

patients on strong inhibitors [of] the use of [m]ifepristone.” 

Id. Lee also noted that, “[b]ased on the results of this 

study, the effect of moderate CYP3A inhibitors on mifepristone pharmacokinetics may need to be addressed.” 

J.A. 866. 

In approving Corcept’s NDA, the FDA also approved 

the prescribing information for Korlym contained in its label. J.A. 839–49. The FDA-approved Korlym label “recommended [a] starting dose [of] 300 mg once daily” and

allowed for increasing the dosage “in 300 mg increments to 

a maximum of 1200 mg once daily” based on clinical assessments. J.A. 839. In addition to those conditions, the Korlym label warned against using mifepristone “with strong 

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4 TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 

CYP3A inhibitors” and limited the “mifepristone dose to 

300 mg per day when used with strong CYP3A inhibitors.” 

J.A. 839. 

B 

Corcept conducted the drug-drug interaction study described in Lee, collecting data on co-administration of mifepristone with a strong CYP3A inhibitor. Based on that 

data, Corcept sought and received the ’214 patent. The ’214 

patent relates to methods of treating Cushing’s syndrome 

by co-administering mifepristone and a strong CYP3A inhibitor. Claim 1 is representative for purposes of this appeal:

A method of treating Cushing’s syndrome in a patient who is taking an original once-daily dose of 

1200 mg or 900 mg per day of mifepristone, comprising the steps of:

reducing the original once-daily dose to an 

adjusted once-daily dose of 600 mg mifepristone,

administering the adjusted once-daily dose 

of 600 mg mifepristone and a strong 

CYP3A inhibitor to the patient, 

wherein said strong CYP3A inhibitor is selected from the group consisting of ketoconazole, itraconazole, nefazodone, ritonavir, 

nelfmavir, indinavir, boceprevir, clarithromycin, conivaptan, lopinavir, posaconazole, 

saquinavir, telaprevir, cobicistat, troleandomycin, tipranivir, paritaprevir, and 

voriconazole. 

After Corcept asserted the ’214 patent against Teva in 

district court, Teva sought post-grant review of claims 1–

13. Teva argued those claims would have been obvious in 

light of Korlym’s label and Lee, optionally in combination 

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TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 5

with FDA guidance on drug-drug interaction studies. In 

support of its petition, Teva provided a declaration from 

Dr. David J. Greenblatt. Most relevant here, Dr. Greenblatt opined that, based on the Korlym label and Lee, “it 

was reasonably likely that 600 mg [per day of mifepristone] 

would be well tolerated and therapeutically effective when 

co-administered with a strong CYP3A inhibitor.” J.A. 681. 

The Board instituted review on all asserted grounds. 

In its final-written decision, the Board held Teva had 

failed to prove claims 1–13 would have been obvious to a 

skilled artisan. It first construed the claims to require safe 

administration of mifepristone. Final Decision at *7–9. 

Then, the Board found Teva failed to show that a skilled 

artisan would have had a reasonable expectation of success 

for safe co-administration of more than 300 mg of mifepristone with a strong CYP3A inhibitor. Id. at *10–22. In doing so, it discredited the above-quoted statement from

Dr. Greenblatt, finding it inconsistent with his later testimony and other evidence in the record. Teva appeals. We 

have jurisdiction under 28 U.S.C. § 1295(a)(4).

II

Teva faults the Board for, in its view, committing two 

legal errors. First, it claims the Board required precise predictability, rather than a reasonable expectation of success, 

in achieving the claimed invention. That is, Teva argues 

the Board improperly required it “to show an expectation 

that the specific dose recited in the claims would have been 

safe.” Appellant’s Br. at 41. Second, Teva claims the Board 

ought to have applied our prior-art-range precedents. In 

Teva’s view, the Board committed legal error when it found 

Teva had failed to prove the general working conditions 

disclosed in the prior art encompassed the claimed invention. We do not agree. 

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6 TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 

A 

We start by addressing Teva’s reasonable-expectationof-success argument. “The presence or absence of a reasonable expectation of success is . . . a question of fact,” which

we review for substantial evidence. Intelligent Bio-Sys., 

Inc. v. Illumina Cambridge Ltd., 821 F.3d 1359, 1366 (Fed. 

Cir. 2016). Whether the Board applied the correct standard in assessing reasonable expectation of success, however, is a question of law that we review de novo. See Endo 

Pharms. Inc. v. Actavis LLC, 922 F.3d 1365, 1377–78 (Fed. 

Cir. 2019). 

The Board did not err by requiring Teva to show a reasonable expectation of success for a specific mifepristone 

dosage. The reasonable-expectation-of-success analysis 

must be tied to the scope of the claimed invention. See Allergan, Inc. v. Apotex Inc., 754 F.3d 952, 966 (Fed. Cir. 

2014) (“[F]ailure to consider the appropriate scope of the 

. . . claimed invention in evaluating the reasonable expectation of success . . . constitutes a legal error . . . .”); see also 

Intelligent Bio-Sys., Inc., 821 F.3d at 1367. Here, claim 1 

of the ’214 patent requires safe administration of a specific 

amount of mifepristone, 600 mg per day. See Final Decision at *7–9 (construing claims to require safe administration, rather than just administration). Thus, the Board 

was required to frame its reasonable-expectation-of-success analysis around that specific dosage of mifepristone. 

To be clear, this does not mean Teva was required to prove

a skilled artisan would have precisely predicted safe co-administration of 600 mg of mifepristone. Absolute predictability is not required. See, e.g., Pfizer, Inc. v. Apotex, Inc., 

480 F.3d 1348, 1364 (Fed. Cir. 2007). But Teva was required to prove a reasonable expectation of success in 

achieving the specific invention claimed, a 600 mg dosage. 

Applying that standard, the Board found Teva had 

failed to prove a reasonable expectation of success. It found

that Teva had “not established . . . that [a skilled artisan] 

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TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 7

would reasonably have expected co-administration of more 

than 300 mg of mifepristone with a strong CYP3A inhibitor 

to be safe for the treatment of Cushing’s syndrome or related symptoms in patients.” Final Decision at *22; see also

id. at *10–22. It went even further, finding “the evidence 

support[ed] that [a skilled artisan] would have had no expectation as to whether co-administering dosages of mifepristone above the 300 mg/day threshold set forth in the 

Korlym label would be successful.” Id. at *20 (emphasis 

added). Because there was no expectation of success for 

any dosage over 300 mg per day, there was no expectation 

of success for the specific 600 mg per day dosage. See id. at 

*14 (finding no expectation of success for 600 mg per day 

dosage). Under our precedent, those findings were dispositive. Honeywell Int’l Inc. v. Mexichem Amanco Holding 

S.A. DE C.V., 865 F.3d 1348, 1356 (Fed. Cir. 2017) (holding 

the reasonable-expectation-of-success requirement is not 

satisfied when the skilled artisan would have had no expectation of success). Nothing about this analysis required 

precise predictability, only a reasonable expectation of success tied to the claimed invention.

The Board’s treatment of Dr. Greenblatt’s testimony is 

similar. Before institution, Dr. Greenblatt opined that “it 

was reasonably likely that 600 mg [per day of mifepristone] 

would be well tolerated and therapeutically effective when 

co-administered with a strong CYP3A inhibitor.” J.A. 681 

(emphasis added). But the Board discredited that opinion 

based on Dr. Greenblatt’s later, inconsistent testimony 

that “unequivocally” stated a skilled artisan “would have 

no expectation as to whether the co-administration of 600 

mg of mifepristone with ketoconazole would be safe.” Final 

Decision at *11 (emphasis added) (discussing testimony at 

J.A. 5493–94). The Board found the later testimony, unlike 

Dr. Greenblatt’s pre-institution testimony, was consistent 

with his other deposition testimony, id. at *12 (discussing 

J.A. 5511); his post-deposition declaration, id. (discussing 

J.A. 3096–97); and other evidence in the record, id. at *14 

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8 TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 

(citing J.A. 1164–66 (Dr. Greenblatt article), 3111 (Dr. 

Dobbs declaration), 3433 (Dr. Guengerich testimony)). The 

Board then considered and rejected Teva’s attempt to 

square Dr. Greenblatt’s declaration with his deposition testimony. Id. at *13–14. Put simply, the Board found 

Dr. Greenblatt’s testimony supported a finding of no expectation of success in achieving the claimed invention, not 

that Dr. Greenblatt had failed to show the specific claimed 

dosage was absolutely predictable in advance.2 

In sum, we see no reversible error in the Board’s reasonable-expectation-of-success analysis. The Board applied the correct standard, requiring only a reasonable 

expectation of success and tying its analysis to the scope of 

the claimed invention. 

B 

We next address the applicability of our prior-art-range 

cases—i.e., the cases in which a claimed range of values 

overlap the ranges disclosed in the prior art. The Board 

declined to apply those cases because it found Teva had 

failed to prove the general working conditions disclosed in 

the prior art encompass the claimed invention. The scope 

and content of the prior art is a question of fact, reviewed 

for substantial evidence. SIPCO, LLC v. Emerson Elec. 

Co., 980 F.3d 865, 870 (Fed. Cir. 2020). 

“For decades, this court and its predecessor have recognized that 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.” 

E.I. DuPont de Nemours & Co. v. Synvina C.V., 904 F.3d 

996, 1006 (Fed. Cir. 2018) (quotation marks omitted). “A 

more specific application of this general principle is that a 

2 To the extent Teva challenges the Board’s credibility findings, see Appellant’s Br. at 39–40, they are supported by substantial evidence.

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prima facie case of obviousness typically exists when the 

ranges of a claimed composition overlap the ranges disclosed in the prior art.” Id. (quotation marks and alterations omitted). But overlap is not strictly necessary for a 

conclusion of obviousness: “obviousness exists when the 

claimed range and the prior art range do not overlap but 

are close enough such that one skilled in the art would have 

expected them to have the same properties.” In re Peterson, 

315 F.3d 1325, 1329 (Fed. Cir. 2003); accord In re Brandt, 

886 F.3d 1171, 1177 (Fed. Cir. 2018); Valeant Pharms. Int’l, 

Inc. v. Mylan Pharms. Inc., 955 F.3d 25, 32 (Fed. Cir. 2020). 

Substantial evidence supports the Board’s finding that

the general working conditions disclosed in the prior art 

did not encompass the claimed invention, i.e., there was no 

overlap in ranges. In the Board’s view, “the evidence of 

record support[ed] that the general working conditions limited co-administration of mifepristone with a strong 

CYP3A inhibitor to just 300 mg/day.” Final Decision at 

*21. Rephrased, the prior art capped the range of co-administration dosages at 300 mg per day. For support, the 

Board cited the Korlym label, id., which cautioned that 

“[m]ifepristone should be used in combination with strong 

CYP3A inhibitors only when necessary, and in such cases 

the dose should be limited to 300 mg per day.” J.A. 844. 

And it also noted how industry publications echoed this 

limitation. Final Decision at *21 (citing J.A. 1279–80 

(“[T]he dose of mifepristone should not exceed 300 mg/day 

if used in combination with ketoconazole.”), 4164 (For coadministration with ketoconazole, “the maximum daily 

dose of mifepristone should be 300 mg.”)). The Board’s 

finding that the prior art ranges do not overlap with the 

claimed range is supported by substantial evidence.

And the Board’s reasonable-expectation-of-success 

finding, which we have already upheld, forecloses Teva’s 

reliance on monotherapy doses above 300 mg per day. Teva 

claims those monotherapy dosages create an overlap with 

the claimed range. But monotherapy dosages alone cannot 

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10 TEVA PHARMACEUTICALS USA v. CORCEPT THERAPEUTICS, INC. 

create an overlap with the claimed range, which is limited 

to co-administering mifepristone with a strong CYP3A inhibitor. Thus, the only remaining question is whether a 

skilled artisan would have expected monotherapy and coadministration dosages to behave similarly. As the Board 

found, a skilled artisan would have had no such expectation. And we have already upheld that finding as supported by substantial evidence.

III

Teva claims this is an “uncommonly clear-cut obviousness case.” Appellant’s Br. at 37. It describes the prior art 

as “disclos[ing] the problem, . . . the solution, . . . and the 

way to find the solution.” Id. In doing so, it ignores the 

reasonable-expectation-of-success requirement. At best, 

the prior art directed a skilled artisan to try combining the 

Korlym Label, Lee, and the FDA guidance. But without 

showing a reasonable expectation of success, Teva did not 

prove obviousness. Since the Board applied the appropriate legal standards in finding no expectation of success and 

its fact findings are supported by substantial evidence, we 

affirm.

AFFIRMED

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