NOTE: This disposition is nonprecedential. 

United States Court of Appeals 

for the Federal Circuit ______________________ 

ALLERGAN, INC., 

Plaintiff-Appellee, 

v. 

BARR LABORATORIES, INC., 

TEVA PHARMACEUTICALS USA, INC., 

AND TEVA PHARMACEUTICAL INDUSTRIES LTD., 

Defendants-Appellants, 

AND 

SANDOZ INC., 

Defendant-Appellant. 

______________________ 

2012-1040, -1054 

______________________ 

Appeals from the United States District Court for the 

District of Delaware in No. 09-CV-0333, Judge Sue L. 

Robinson. 

______________________ 

Decided: January 28, 2013 

______________________ 

JONATHAN E. SINGER, Fish & Richardson, P.C., of 

Minneapolis, Minnesota, argued for plaintiff-appellee. 
2 ALLERGAN v. BARR LABS

With him on the brief were DEANNA J. REICHEL; and 

JUANITA R. BROOKS, of San Diego, California; and 

DOUGLAS E. MCCANN, of Wilmington, Delaware. Of 

counsel on the brief was JEFFREY T. THOMAS, Gibson, 

Dunn & Crutcher LLP, of Irvine, California. 

MEREDITH MARTIN ADDY, Steptoe & Johnson, LLP, of 

Chicago, Illinois, argued for defendants-appellants. With 

her on the brief for Sandoz, Inc. were THOMAS J. FILARSKI 

and BRANDON C. HELMS. On the brief for Barr Laboratories, Inc., et al, were GEORGE C. LOMBARDI and BRADLEY 

C. GRAVELINE, Winston & Strawn, LLP, of Chicago, 

Illinois. 

______________________ 

Before RADER, Chief Judge, BRYSON,



 and WALLACH, 

Circuit Judges. 

WALLACH, Circuit Judge. 

 Barr Laboratories, Inc., Teva Pharmaceuticals USA, 

Inc., and Teva Pharmaceutical Industries Ltd. (collectively, “Barr”), and Sandoz Inc. (“Sandoz”) appeal from 

the decision of the United States District Court for the 

District of Delaware, which held that Barr’s and Sandoz’s 

proposed products (described in Abbreviated New Drug 

Applications (“ANDA”) Nos. 91-194 and 200487, respectively) infringed claim 10 of Allergan, Inc.’s (“Allergan”) 

U.S. Patent No. 5,688,819 (“the ’819 patent”) and that the 

asserted claim was not invalid.1 Allergan, Inc. v. Barr 

 

 Judge Bryson assumed senior status on January 7, 2013. 

1 Allergan also asserted claims 1-3 of its U.S. 

Patent 6,403,649 (“the ’649 patent”), and the district court 

likewise found the ’649 patent was not invalid and infringed by Barr’s and Sandoz’s ANDAs. Allergan, 808 F. 
 ALLERGAN v. BARR LABS 3 

 

Labs., Inc., 808 F. Supp. 2d 715, 717 (D. Del. 2011). 

Because the district court correctly construed the relevant 

claim term and determined the asserted claim was not 

obvious, we affirm. 

BACKGROUND

 Allergan markets and sells Lumigan®, which was 

approved by the Food and Drug Administration (“FDA”) 

to reduce intraocular pressure (“IOP”) in people with 

ocular hypertension or glaucoma. The active ingredient 

in Lumigan® is bimatoprost. Allergan’s ’819 patent 

claims bimatoprost and methods of using bimatoprost to 

treat ocular hypertension or glaucoma. 

1. Background of the Invention 

In a healthy eye, proper IOP is maintained by 

aqueous humor, which is fluid between the cornea and the 

lens of the eye that transports nutrients like vitamins, 

sugars, and amino acids to the cornea. Too much aqueous 

humor disrupts IOP and poses a substantial risk factor 

for developing glaucoma. PGF2α is a naturally-occurring 

prostaglandin that is known to lower IOP by increasing 

the outflow of aqueous humor from the eye. Prostaglandins are a class of naturally-occurring substances, all of 

which share the following twenty-carbon basic structure: 

Supp. 2d at 736. However, the ’649 patent expired on 

September 21, 2012 and thus is not at issue in this appeal. 
4 ALLERGAN v. BARR LABS

Allergan, 808 F. Supp. 2d at 719. The above carbon atoms 

are numbered from 1 to 20, with 1 through 7 forming an α

(alpha) chain, 13 through 20 forming an ω (omega) chain, 

and 8 through 12 forming a five-membered (cyclopentane) 

ring. The C-1 position (highlighted by the box above) 

features carboxylic acid, which is present in all naturallyoccurring prostaglandins.

 As noted, it was known prior to the invention at issue 

that PGF2α lowered IOP. The prior art also revealed that 

certain lipid-soluble esters of PGF2α lowered IOP, and 

actually showed greater hypotensive effects than the 

parent compound PGF2α. ’819 patent col. 2 ll. 9-38. According to the ’819 patent’s specification, however, prostaglandins like PGF2α and its isopropyl ester were 

associated with negative side effects like “ocular surface 

hyperemia” (red eye) and “foreign-body sensation.” Id. col. 

2 ll. 41-46. The ’819 patent discloses that certain compounds that replace the carboxylic acid group with a nonacidic substituent can reduce these side effects while 

retaining the desired IOP-lowering effect. Id. col. 3 ll. 9-

18. One such compound is bimatoprost (cyclopentane Nethyl heptenamide-5-cis-2-(3α-hydroxy-5-phenyl-1-transpentenyl)-3, 5-dihydroxy, [1α,2β,3α,5α]). Id. col. 7 ll. 44-46.

Bimatoprost is PGF2α, with an ethyl amide instead 

of a carboxylic acid group at the C-1 position and a phenyl 
 ALLERGAN v. BARR LABS 5 

ring at C-17.2 [J.A.10] Bimatoprost has the structure 

depicted below: 

Allergan, 808 F. Supp. 2d at 720. Bimatoprost lowers IOP 

by increasing the flow of aqueous humor leaving the eye. 

2. Patent-in-Suit 

The ’819 patent is related to and claims priority 

from U.S. Patent No. 5,352,708 (“the ’708 patent”), filed 

on September 21, 1992. The ’819 patent was issued on 

November 18, 1997, and was extended for 698 days as a 

result of the FDA’s regulatory review of Lumigan®. 

Asserted claim 10 of the ’819 patent ultimately depends 

from independent claim 5, which recites:

5. A method of treating ocular hypertension or 

glaucoma which comprises applying to the eye an 

amount sufficient to treat ocular hypertension or 

glaucoma of the formula 

 2 Bimatoprost is a prostamide and is also 

known as 17-phenyl PGF2α C-1 ethylamide. 
6 ALLERGAN v. BARR LABS

wherein . . . X is a radical selected from the group 

consisting of –OR4 and –N(R4)2 wherein R4 is selected from the group consisting o[f] hydrogen, a 

lower alkyl radical having from one to six carbon 

atoms, 

wherein R5 is a lower alkyl radical having from 

one to six carbon atoms . . . . 

’819 patent col. 13 l. 49 – col. 14 l. 7 (emphasis added to 

disputed claim term). Dependent claim 10 discloses five 

compounds that may be used in the treatment of ocular 

hypertension or glaucoma in which X is –N(R4)2. Id. col. 

14 l. 55 – col. 15 l. 7. One of these compounds is bimatoprost, listed as cyclopentane N-ethyl heptenamide-5-cis-2-

(3α-hydroxy-5-phenyl-1-trans-pentenyl)-3, 5-dihydroxy, 

[1α,2β,3α,5α]. Id. col. 15 ll. 1-3. 

3. Barr’s and Sandoz’s Abbreviated New 

 Drug Applications 

On March 26, 2009, Barr filed an ANDA for a generic version of Lumigan®, listing Allergan’s ’819 patent 

as one of the Orange Book-listed patents associated with 

Lumigan®.3 Barr’s ANDA contained a Paragraph IV 

certification stating that Barr believed each relied-upon 

Orange Book patent was “invalid or [would] not be in-

 3 The FDA lists all patents protecting FDAapproved drugs in a publication titled the “Approved Drug 

Products With Therapeutic Equivalence Evaluations,” 

which is generally referred to as the “Orange Book.” 

Caraco Pharm. Labs., Ltd. v. Forest Labs., Ltd., 527 F.3d 

1278, 1282 (Fed. Cir. 2008) (citing 21 U.S.C. § 355(b)(1), 

(c)(2)). 
 ALLERGAN v. BARR LABS 7 

fringed by the manufacture, use, or sale of the new drug 

for which the application [was] submitted.” 21 U.S.C. § 

355(b)(2)(A)(iv). Sandoz likewise filed an ANDA for a 

generic version of Lumigan®, also with an accompanying 

Paragraph IV certification. Allergan filed patent infringement suits against Barr and Sandoz; the suits were 

consolidated into one action for a bench trial on patent 

invalidity and infringement. 

4. District Court Proceedings 

A. Claim Construction 

The only claim term disputed before the district 

court was –N(R4)2 as used in claim 5, on which asserted 

claim 10 depends. The parties disagree whether or not 

–N(R4)2 requires identical R4 substituents. If it does, 

bimatoprost’s use of nonidentical R4 substituents—

hydrogen (H) and an ethyl group (CH2CH3)—would fall 

outside the protection of the ’819 patent. The district 

court initially agreed with Barr and Sandoz that “the 

plain and ordinary meaning” of –N(R4)2 suggested that 

identical R4 substituents were required; however, it 

ultimately found that Allergan had acted as its own 

lexicographer by defining –N(R4)2 to permit nonidentical 

R4 elements. Therefore, the district court held that, as 

used in the ’819 patent, the –N(R4)2 limitation did not 

require the R4 substituents to be identical. Allergan, Inc., 

808 F. Supp. 2d at 726-27. Given this claim construction, 

the district court found that bimatoprost satisfied all 

limitations of the asserted claims, and consequently found 

Barr’s and Sandoz’s proposed uses of bimatoprost as set 

forth in their ANDAs constituted infringement of the ’819 

patent. 
8 ALLERGAN v. BARR LABS

B. Invalidity 

The district court found that asserted claim 10 of 

the ’819 patent was not invalid, and rejected Barr and 

Sandoz’s arguments based upon anticipation and obviousness. The primary invalidity reference asserted 

during trial was a patent to Johan Stjernschantz, published as Patent Cooperation Treaty Application No. WO 

90/02253 on March 22, 1990 and entitled “Prostaglandin 

Derivatives for the Treatment of Glaucoma or Ocular 

Hypertension” (“Stjernschantz”). Barr and Sandoz’s 

expert witness, Dr. Ashim Kumar Mitra, testified that 

asserted claim 10 was obvious over Stjernschantz, whether alone or in combination with other prior art, including 

unexamined Japanese Patent Application No. S49-69636 

(“JP ’636”).4 Barr and Sandoz also asserted post-trial that 

all of the asserted claims were obvious over Stjernschantz 

in combination with a chapter in the textbook “Prodrugs: 

Topical and Ocular Drug Delivery” entitled “Improved 

Ocular Drug Delivery with Prodrugs” (“Lee & Bundgaard”). 

Stjernschantz discloses IOP-reducing derivatives of 

certain prostaglandins. Two such derivatives are disclosed compounds 2 and 9, which are both isopropyl esters 

that convert into bimatoprost-free acid upon hydrolysis in 

the eye.5 A third disclosed derivative is compound 17, 

 4 Other prior art discussed by Dr. Mitra at trial 

included: U.S. Patent No. 4,599,353, and a chapter of a 

1977 textbook (“Design of Biopharmaceutical Properties 

through Prodrugs and Analogs”) entitled “Physical Model 

Approach to the Design of Drugs with Improved Intestinal 

Absorption.” 5 Compound 9 differs from compound 2 only in 

that it has a single bond between C-13 and C-14, whereas 

compound 2 has a double bond in that position. Com-
 ALLERGAN v. BARR LABS 9 

 

bimatoprost-free acid or 17-phenyl PGF2α, which features 

a carboxylic acid functional group at C-1. The structural 

difference between bimatoprost and these Stjernschantz 

derivatives is that bimatoprost features an ethyl amide 

functional group at the C-1 position, whereas compounds 

2 and 9 have an isopropyl ester at C-1, and compound 17 

has carboxylic acid. 

However, these obviousness theories were undermined when “Mitra’s credibility was eviscerated on crossexamination.” Allergan, 808 F. Supp. 2d at 733. Finding 

“Mitra’s credibility flawed on a fundamental level,” the 

district court accorded no weight to his testimony. Id. at 

735. The court then declined to “review the prior art 

references and weigh their import absent the guidance of 

an expert.” Id. at 736 n.21. Furthermore, based on its 

finding that Barr and Sandoz had improperly switched 

obviousness theories after Dr. Mitra’s testimony was 

discredited, the district court held Barr and Sandoz had 

waived any obviousness theory that relied “primarily on 

JP ’636, or that combine[d] Stjernschantz with Lee & 

Bundgaard.” Id. at 735. Due to the lack of credible evidence to support Barr’s and Sandoz’s obviousness theories, plus the waiver of post-trial obviousness theories, the 

court held that Barr and Sandoz failed to prove obviousness of the asserted claim by clear and convincing evidence. 

Barr and Sandoz filed this timely appeal. This 

court has jurisdiction pursuant to 28 U.S.C. § 1295(a)(1). 

pound 9 became latanoprost, which is marketed as Xalatan®, a leading antiglaucoma treatment. 
10 ALLERGAN v. BARR LABS

DISCUSSION

1. The District Court Correctly Held That –N(R4)2

As Used in the ’819 Patent Includes Compounds 

With Non-Identical R4 Elements 

The district court determined that “the plain and 

ordinary meaning of –N(R4)2 would support [Barr and 

Sandoz’s] construction that the R4 elements are identical 

functional groups,” but went on to find that Allergan had 

acted as its own lexicographer in defining –N(R4)2 contrary to its ordinary meaning. Allergan, 808 F. Supp. 2d 

at 725-26. Barr and Sandoz appeal the district court’s 

construction of the –N(R4)2 term, arguing that the plain 

and ordinary meaning of –N(R4)2 requires identical R4

elements, and that Allergan failed to make any express 

statement departing from that plain and ordinary meaning. 

 Claim construction is a question of law subject to de 

novo review. Cybor Corp. v. FAS Techs., Inc., 138 F.3d 

1448, 1456 (Fed. Cir. 1998) (en banc). Claim terms are 

generally given their “ordinary and customary meaning” 

as they would be understood by a person of ordinary skill 

in the art. Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 

(Fed. Cir. 2005) (en banc). “Importantly, the person of 

ordinary skill in the art is deemed to read the claim term 

not only in the context of the particular claim in which the 

disputed term appears, but in the context of the entire 

patent, including the specification.” Id. at 1313. Indeed, 

“the context in which a term is used in the asserted claim 

can be highly instructive,” as can other claims of the 

patent in question. Id. at 1314. The inventor’s lexicography governs when “the specification [ ] reveal[s] a special 

definition given to a claim term by the patentee that 

differs from the meaning it would otherwise possess.” Id.

at 1316. 
 ALLERGAN v. BARR LABS 11 

 In this case, a person of ordinary skill in the art 

considering the entire ’819 patent would construe the 

disputed –N(R4)2 term to encompass nonidentical R4

elements. The disputed claim term arises in independent 

claim 5, in which –N(R4)2 is used to claim one of the 

molecules that may be located at the C-1 position of the 

compound. Claim 5 further recites that R4 must be selected from a Markush group6 “consisting of hydrogen, a 

lower alkyl radical having from one to six carbon atoms, 

wherein R5 is a lower alkyl radical having from one to six 

carbon atoms.” ’819 patent col. 13 ll. 31-39. [J.A.49] 

Asserted claim 10 ultimately depends from claim 5 and 

expressly includes three compounds with nonidentical R4

elements, including bimatoprost.7 Specifically, bimatoprost has two different substituents at the R4 position, 

both of which are claimed in the Markush group: hydrogen (H) and an ethyl group (CH2CH3). Id. col. 14 l. 60 - 

col. 15 l. 7. Two other compounds listed in claim 10 also 

 6 “A Markush group is a listing of specified alternatives of a group in a patent claim, typically expressed in the form: a member selected from the group 

consisting of A, B, and C.” Abbott Labs. v. Baxter Pharm. 

Prods., Inc., 334 F.3d 1274, 1280 (Fed. Cir. 2003). 

7 Claim 9 ultimately depends from claim 5 and 

claims –N(R4)2 as one of the molecules at the C-1 position. 

’819 patent col. 14 ll. 56-57. Claim 10, in turn, depends 

from claim 9. Id. col. 14 l. 58. Therefore, although Barr 

and Sandoz stress that the –N(R4)2 term does not appear 

in claim 10, the compounds in claim 10 plainly contain –

N(R4)2. 
12 ALLERGAN v. BARR LABS

feature differing R4 elements.8 Id. col. 14 ll. 65-67; col. 15 

ll. 4-6. Consistently, claim 18, depending from claim 11, 

recites the same three compounds as having a –N(R4)2

molecule at the C-1 position. Id. col. 17 ll. 14-22. These 

same three compounds, all with nonidentical R4 substituents of –N(R4)2, also appear in the specification’s list of 

“novel compounds [that] may be used in the pharmaceutical compositions and the methods of treatment of the 

present invention.” Id. col. 7 ll. 19-21, 41-49. 

Barr and Sandoz nevertheless focus on the district 

court’s preliminary conclusion that the plain and ordinary 

meaning of –N(R4)2 required identical R4 elements. 

However, this preliminary conclusion was based on extrinsic evidence, such as expert testimony that “[t]he (X)y

nomenclature” was “commonly used” to represent identical substituents, Allergan, 808 F. Supp. 2d at 725, which 

failed to consider the –N(R4)2 term as it was used in the 

’819 patent. Phillips, 415 F.3d at 1321 (“Properly viewed, 

the ‘ordinary meaning’ of a claim term is its meaning to 

the ordinary artisan after reading the entire patent.”) 

(emphasis added). When the district court later considered the term in the context of the ’819 patent, it concluded that Allergan “clearly manifest[ed]” in the claims 

and specification that the –N(R4)2 term was meant to 

encompass nonidentical R4 elements such as bimatoprost. 

Allergan, 808 F. Supp. 2d at 726. Barr and Sandoz’s 

argument regarding the plain meaning of –N(R4)2 is 

unpersuasive; when properly construed in light of the 

 8 These compounds are: cyclopentane Nisopropyl heptenamide-5-cis-2-(3α-hydroxy-5-phenyl-1-

trans-pentenyl)-3, 5-dihydroxy, [1α,2β,3α,5α], and cyclopentane N-methyl heptenamide-5-cis-2-(3α-hydroxy-5-phenyl1-trans-pentenyl)-3, 5-dihydroxy, [1α,2β,3α,5α]. ’819 patent 

col. 14 ll. 65-67; col. 15 ll. 4-6 (emphases added). 
 ALLERGAN v. BARR LABS 13 

entire patent, the –N(R4)2 term plainly encompasses 

nonidentical R4 substituents. 

2. The District Court Correctly Held That the 

Asserted Claim Is Not Invalid As Obvious 

The district court held that Barr and Sandoz failed 

to prove obviousness by clear and convincing evidence. 

Barr and Sandoz appeal this determination. First, they 

argue that the district court’s adverse credibility determination of Dr. Mitra did not excuse the court from its 

obligation to independently review the submitted prior art 

references. Additionally, they assert that their obviousness theories are supported even when considering only 

the testimony of Allergan’s experts and corroborating 

evidence. 

“The ultimate judgment of obviousness is a legal 

determination,” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 

398, 427 (2007), which we review de novo, Procter & 

Gamble Co. v. Teva Pharm. USA, Inc., 566 F.3d 989, 993 

(Fed. Cir. 2009). Following a bench trial, underlying 

findings of fact are reviewed for clear error. Alza Corp. v. 

Mylan Labs., Inc., 464 F.3d 1286, 1289 (Fed. Cir. 2006). A 

party seeking to invalidate a patent based on obviousness 

must prove such obviousness by clear and convincing 

evidence. Procter & Gamble Co., 566 F.3d at 993-94. A 

patented invention is obvious when “a skilled artisan 

would have been motivated to combine the teachings of 

the prior art references to achieve the claimed invention, 

and [ ] the skilled artisan would have had a reasonable 

expectation in doing so.” Pfizer, Inc. v. Apotex, Inc., 480 

F.3d 1348, 1361 (Fed. Cir. 2007). 
14 ALLERGAN v. BARR LABS

A. The District Court Did Not Err In Finding Expert 

Testimony Was Required To Show Invalidity 

The district court found that Dr. Mitra’s credibility 

was “flawed on a fundamental level” and declined to 

assign any weight to his opinions. Allergan, 808 F. Supp. 

2d at 735. This was a fair assessment of the testimony of 

Dr. Mitra, whose prevarication and inconsistency were 

repeatedly demonstrated during Allergan’s cross examination. For instance: (1) Dr. Mitra incorrectly drew the 

bimatoprost molecule and utilized slides that inaccurately 

represented bimatoprost; (2) his previous testimony given 

at another trial directly contradicted his stated opinion 

that Stjernschantz persuasively showed the hypotensive 

effect of prostaglandin analogues; and (3) his previously 

published opinions that bimatoprost was more effective 

than latanoprost and acted through a “novel prostamide 

receptor” contradicted his trial testimony that bimatoprost was just a “delivery vehicle” for bimatoprost-free 

acid. Id. at 733-34. 

The district court declined to independently “review 

the prior art references and weigh their import absent the 

guidance of an expert.” Allergan, 808 F. Supp. 2d at 736 

n.21. On appeal, Barr and Sandoz challenge this refusal 

to consider their obviousness theories, contending that 

discrediting Dr. Mitra “did not then permit the [district] 

court to ignore all other evidence. . . .” BB.49. 

This court has noted that “‘expert testimony regarding matters beyond the comprehension of laypersons 

is sometimes essential,’ particularly in cases involving 

complex technology.” Wyers v. Master Lock Co., 616 F.3d 

1231, 1240 n.5 (Fed. Cir. 2010) (quoting Centricut, LLC v. 

Esab Group, Inc., 390 F.3d 1361, 1369-70 (Fed. Cir. 

2004)). Obviousness is one area in which expert testimony may be required. See Proveris Scientific Corp. v. 

Innovasystems, Inc., 536 F.3d 1256, 1267 (Fed. Cir. 2008) 
 ALLERGAN v. BARR LABS 15 

(holding the district court did not abuse its discretion “in 

requiring [the party asserting invalidity] to present 

expert testimony in order to establish invalidity” because 

the technology was “sufficiently complex to fall beyond the 

grasp of an ordinary layperson.”). In complex cases where 

invalidity on the grounds of obviousness is asserted, 

“expert testimony may be critical, for example, to establish the existence of certain features in the prior art or the 

existence (or lack thereof) of a motivation to combine 

references.” Wyers, 616 F.3d at 1240 n.5 (interior references omitted). 

 The district court appears to have found this case to 

be “sufficiently complex to fall beyond [the] grasp of 

ordinary layperson[s].” Allergan, 808 F. Supp. 2d at 736 

n.21 (characterizing the holding of Proveris Scientific 

Corp., 536 F.3d at 1367). Indeed, this is not a case where 

“[t]he technology is simple,” Sundance, Inc. v. DeMonte 

Fabricating Ltd., 550 F.3d 1356, 1365 (Fed. Cir. 2008), or 

where the references are “easily understandable without 

the need for expert explanatory testimony,” Union Carbide v. American Can Co., 724 F.2d 1567, 1573 (Fed. Cir. 

1984). Additionally, this is emphatically not a case where 

“[t]he factual inquiries underlying [the] determination of 

obviousness are not in material dispute.” Sundance, Inc., 

550 F.3d at 1365; see, e.g., Allergan, Inc., 808 F. Supp. 2d 

at 721 (explaining that “[b]imatoprost’s mechanism of 

action is greatly debated in this case,” with Barr and 

Sandoz arguing it functions as a “prodrug” with no inherent biological activity, and Allergan arguing that it is not 

a prodrug, but rather acts on a novel prostamide receptor). Although in some cases, “the legal determination of 

obviousness may include recourse to logic, judgment, and 

common sense, in lieu of expert testimony,” Wyers, 616 

F.3d at 1239, the district court did not err in finding that 

common sense and logic were not sufficiently illuminating 
16 ALLERGAN v. BARR LABS

in this case to carry Barr and Sandoz’s burden of proving 

obviousness. 

B. Allergan’s Expert’s Testimony Does Not Support 

Barr and Sandoz’s Obviousness Theories 

On appeal, Barr and Sandoz argue that their obviousness theories are supported by expert testimony: that 

of Allergan’s expert, Dr. Timothy L. Macdonald, whose 

testimony the district court found to be credible.9 In 

particular, they contend that Dr. Macdonald’s testimony 

supports the three facts needed to show the asserted 

claim is obvious in view of Stjernschantz and other references: (1) Stjernschantz taught that bimatoprost-free acid 

lowered IOP; (2) Stjernschantz’s compound 2 hydrolyzed 

into bimatoprost-free acid when placed in the eye; and (3) 

a skilled artisan would have known that substituting an 

amide for the ester at the C-1 position would result in a 

prodrug that hydrolyzed into bimatoprost-free acid in the 

eye. 

Dr. Macdonald provided testimony consistent with 

the first two propositions. See J.A.2086 (testifying that 

Stjernschantz taught bimatoprost-free acid would have 

the effect of lowering IOP); J.A.2062-63 (testifying that 

Stjernschantz taught compound 2 would hydrolyze into 

bimatoprost-free acid once in the body). However, his 

testimony contradicts the third requirement. Dr. Macdonald instead asserted that one of skill in the art would 

not have believed substituting an amide at the C-1 position would create a prodrug that hydrolyzed into bimato-

 9 Barr and Sandoz also rely on other Allergan 

witnesses to support their obviousness claim, but we have 

carefully reviewed the record and find nothing in the 

testimony of these additional witnesses that could override Dr. Macdonald’s expert opinion of non-obviousness or 

establish clear and convincing evidence of obviousness. 
 ALLERGAN v. BARR LABS 17 

 

prost-free acid once in the eye. To the contrary, Dr. 

Macdonald testified that an amide converts into carboxylic acid at such a slow rate that “one doesn’t consider it 

as a candidate [as a prodrug].” J.A.2065-66. He explained 

that “a prodrug approach relies on efficient conversion of 

the prodrug into the drug,” and the “500-year half life” of 

an amide in water was “not an efficient conversion.” 

J.A.2067; see also J.A.1996. Dr. Macdonald concluded 

that the prior art did not teach or motivate one of skill in 

the art to substitute an amide at the C-1 position to create 

a glaucoma drug. Given Dr. Macdonald’s testimony to the 

contrary, Barr and Sandoz can point to no credible expert 

testimony showing that substituting an amide at the C-1 

position would have been obvious to a skilled artisan at 

the time of the invention. Because of this gap, we hold 

that Barr and Sandoz have failed to show obviousness of 

the ’819 patent by clear and convincing evidence.10

CONCLUSION

For the foregoing reasons, we affirm the district 

court’s claim construction and determination of nonobviousness. 

AFFIRMED

10 We need not determine whether the district 

court abused its discretion in finding that Barr and Sandoz waived their post-trial obviousness theories, because, 

as determined above, the record contains insufficient 

expert testimony to support any of Barr and Sandoz’s 

obviousness theories.