Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-12-01569/USCOURTS-ca13-12-01569-0/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 

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United States Court of Appeals 

for the Federal Circuit ______________________ 

TEVA PHARMACEUTICALS USA, INC.,

TEVA PHARMACEUTICAL INDUSTRIES, LTD., 

TEVA NEUROSCIENCE, INC., 

YEDA RESEARCH AND DEVELOPMENT CO., LTD.,

Plaintiffs-Appellees

v.

SANDOZ, INC., MOMENTA PHARMACEUTICALS 

INC.,

Defendants-Appellants

MYLAN PHARMACEUTICALS INC., MYLAN INC., 

NATCO PHARMA LTD.,

Defendants-Appellants

SANDOZ INTERNATIONAL GMBH, 

NOVARTIS AG,

Defendants

______________________ 

2012-1567, 2012-1568, 2012-1569, 2012-1570

______________________ 

Appeals from the United States District Court for the 

Southern District of New York in Nos. 08-CV-7611, 09-

CV-8824, Judge Barbara S. Jones.

______________________ 

Decided: June 18, 2015

______________________ 

Case: 12-1569 Document: 12-1 Page: 1 Filed: 06/18/2015
2 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

ELIZABETH HOLLAND, Goodwin Procter LLP, New 

York, NY, for plaintiffs-appellees. Also represented by 

DAVID M. HASHMALL; JOHN T. BENNETT, HENRY C. DINGER,

JOHN C. ENGLANDER, NICHOLAS K. MITROKOSTAS, DARYL L.

WIESEN, Boston, MA; WILLIAM G. JAMES, II, WILLIAM M.

JAY, Washington, DC. 

DEANNE MAYNARD, Morrison & Foerster LLP, Washington, DC, for defendants-appellants Sandoz, Inc., Momenta Pharmaceuticals Inc. Also represented by MARC A.

HEARRON, BRIAN ROBERT MATSUI; ANDERS T. AANNESTAD,

DAVID CLARENCE DOYLE, BRIAN M. KRAMER, San Diego, 

CA. 

SHANNON BLOODWORTH, Perkins Coie, LLP, Washington, DC, for defendants-appellants Mylan Pharmaceuticals Inc., Mylan Inc., Natco Pharma Ltd. Also 

represented by BRANDON MICHAEL WHITE; DAVID LEE 

ANSTAETT, DAVID E. JONES, Madison, WI; EVAN CHESLER, 

Cravath Swaine & Moore LLP, New York, NY.

______________________ 

Before MOORE, MAYER, and WALLACH, Circuit Judges.1

Opinion for the court filed by Circuit Judge MOORE. 

Dissenting opinion filed by Circuit Judge MAYER. 

MOORE, Circuit Judge. 

This case comes to us on remand from the Supreme 

Court, which vacated our earlier opinion reversing the 

1 Pursuant to Fed. Cir. Internal Operating Procedure 15 ¶ 2(b)(ii), Circuit Judges Mayer and Wallach were 

designated to replace Circuit Judge Randall R. Rader, 

now retired, and District Judge Dee V. Benson, United 

States District Court for the District of Utah.

 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC . 3

district court’s judgment that certain claims were not 

indefinite (Group I claims), and affirming the district 

court’s holdings that other claims (Group II claims) were 

valid and infringed.2 Teva Pharm. USA, Inc. v. Sandoz, 

Inc., 723 F.3d 1363 (Fed. Cir. 2013), vacated, Teva Pharm. 

USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (2015). Relevant 

to the Group I claims, the Supreme Court held that the

ultimate construction of a claim term is a question of law, 

subject to de novo review, and that underlying subsidiary 

fact findings are subject to clear error review. Teva, 135 

S. Ct. at 837–38, 841–42. During that same time, the 

Supreme Court issued its opinion in Nautilus, Inc. v. 

Biosig Instruments, Inc. (Nautilus II), 134 S. Ct. 2120 

(2014), addressing the standard for indefiniteness. On 

remand, the parties submitted supplemental briefing 

explaining how the appeal should be resolved in light of 

the Supreme Court’s Teva decision. See Teva Pharm. 

USA, Inc. v. Sandoz, Inc., No. 12-1567 (Fed. Cir. Feb. 20, 

2015), ECF No. 137. Applying the legal standards set 

forth in the Supreme Court’s Teva and Nautilus II decisions, we hold that the Group I claims are invalid for 

indefiniteness.3 

2 The asserted patents were: U.S. Patent Nos. 

5,800,808; 5,981,589; 6,048,898; 6,054,430; 6,342,476; 

6,362,161; 6,620,847; 6,939,539; and 7,199,098. The 

Supreme Court decision does not affect our prior holding 

with respect to the Group II claims. For the reasons 

articulated in our earlier opinion, we adopt those holdings.

3 While the case was pending at the Supreme 

Court, all of the patents-in-suit expired, with the exception of U.S. Patent No. 5,800,808. Thus, claim 1 of the 

’808 patent is the sole unexpired Group I claim. Our 

analysis will therefore focus on that claim, but to the 

extent that issues relating to the expired Group I claims 

 

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4 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

BACKGROUND

The facts of this case were recited in this court’s previous opinion. In summary, Appellants submitted Abbreviated New Drug Applications (ANDAs) to the Food and 

Drug Administration (FDA) seeking approval to market 

generic versions of Copaxone®. Teva, which markets 

Copaxone®, sued Appellants for patent infringement 

under 35 U.S.C. § 271(e)(2)(A). Claim 1 of the ’808 patent 

recites a method of making a product called copolymer-1: 

A method of manufacturing copolymer-1, comprising reacting protected copolymer-1 with hydrobromic acid to form trifluoroacetyl copolymer-1, 

treating said trifluoroacetyl copolymer-1 with 

aqueous piperidine solution to form copolymer-1, 

and purifying said copolymer-1, to result in copolymer-1 having a molecular weight of about 5 to 9 

kilodaltons. 

’808 patent claim 1 (emphases added).

Copolymer–1 consists of four different amino acids 

(alanine, glutamic acid, lysine, and tyrosine) combined in 

a certain ratio to make a polypeptide product. A sample 

of polymeric material like copolymer–1 typically consists 

of a mixture of individual polymer molecules that have 

varying molecular weights. There are three different 

measures of molecular weight relevant to this appeal: 

peak average molecular weight (Mp), number average 

molecular weight (Mn), and weight average molecular 

weight (Mw). Each measure is calculated in a different 

manner. The claim does not specify which measure to use 

and in a typical polymer sample, Mp, Mn, and Mw have 

different values. 

remain unresolved, this analysis should be understood to 

apply equally to the other Group I claims. 

 

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The district court rejected the Appellants’ argument 

that the term “molecular weight” was indefinite. Teva 

Pharm. USA, Inc. v. Sandoz, Inc. (Markman Order), 810 

F. Supp. 2d 578, 586–93, 596 (S.D.N.Y. 2011). The district court found credible Dr. Grant’s testimony that Mp is 

the only type of average molecular weight that can be 

directly obtained from a chromatogram and calibration 

curve obtained by the analytical method described in 

Example 1 (Size Exclusion Chromatography or SEC). Id.

at 588, 590. It noted that experts testified that Mn and 

Mw can be obtained from the chromatogram and calibration curve, but doing so would require additional data 

manipulation and calculations not disclosed in the specification. Id. It therefore credited Dr. Grant’s opinion that 

Example 1 implies the use of Mp. Id. The district court

also found that Example 1 corresponds to Figure 1 in the 

patent specification. Id. at 588. It considered Appellants’ 

argument that Figure 1 does not disclose Mp because the 

peaks of the depicted curves do not match the molecular 

weight values reported in the legend. Id. at 590. The 

district court, however, accepted Dr. Grant’s opinion that 

a person of ordinary skill would understand that the 

process of transferring data from a chromatogram could 

cause a shift in the peak of the curves. Id. It therefore 

concluded that the fact that the peaks do not match the 

listed molecular weights does not dissuade the conclusion 

that “molecular weight” means Mp. Id. at 590–91. The 

district court determined that “the prosecution history 

also indicates [average molecular weight] refers to Mp in 

the context of the patents-in-suit.” Id. at 589. It rejected 

as irrelevant the patentee’s response to an indefiniteness 

rejection during the prosecution of the ’847 patent that 

“[o]ne of ordinary skill in the art could understand that 

kilodalton unit implies a weight average molecular 

weight.” Id. at 591–92. It did so on the basis that the 

“statement was incorrect” because each type of average 

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6 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

molecular weight can use the kilodalton. Id. at 592. It 

then concluded that one of ordinary skill would accept the 

patentee’s statement during the prosecution of the ’539 

patent that average molecular weight means Mp. Id. 

Having considered the claims, specification, prosecution 

history and extrinsic evidence, the district court determined that “molecular weight” means Mp in the context of 

the claimed invention and held that the claims are not 

indefinite. Id. 

We reversed the district court’s judgment with respect 

to the Group I claims, holding them indefinite. Teva, 723 

F.3d at 1368–69. Teva filed a petition for a writ of certiorari, arguing to the Supreme Court that in holding the 

claims indefinite, we erred by giving no weight to the 

district court fact findings. Pet. for Writ of Cert., Teva 

Pharm. USA, Inc. v. Sandoz, Inc., No. 13-854, 2014 WL 

230926, at *13–14 (2014). Teva argued that this court’s 

determinations in Cybor Corp. v. FAS Techs., Inc., 138 

F.3d 1448 (Fed. Cir. 1998) (en banc) and Lighting Ballast 

Control LLC v. Philips Elecs. North America Corp., 744 

F.3d 1272 (Fed. Cir. 2014) (en banc) that we review all 

aspects of claim construction de novo was incorrect and 

inconsistent with Fed. R. Civ. P. 52(a)(6). Brief for the 

Petitioner at 18, Teva Pharm. USA, Inc. v. Sandoz, Inc., 

No. 13-854 (2014). It argued that under Fed. R. Civ. P. 

52(a)(6), we should only set aside a district court fact 

finding if such finding is clearly erroneous. The Supreme 

Court agreed. 

The Supreme Court held that “it was proper to treat 

the ultimate question of the proper construction of the 

patent as a question of law in the way that we treat 

document construction as a question of law.” Teva, 135 S. 

Ct. at 837. The reviewing court, however, should review 

subsidiary factual findings under the clearly erroneous 

standard. Id. at 838. The Court explained that “when the 

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district court reviews only evidence intrinsic to the patent 

(the patent claims and specifications, along with the 

patent’s prosecution history), the judge’s determination 

will amount solely to a determination of law” which will 

be reviewed de novo. Id. at 841. If a district court needs 

to consult extrinsic evidence, for example, to understand 

the meaning of a term in the relevant art at the relevant 

time, the court may need to make subsidiary factual 

findings about that extrinsic evidence. Id. The Court 

explained that 

if a district court resolves a dispute between experts and makes a factual finding that, in general, 

a certain term of art had a particular meaning to 

a person of ordinary skill in the art at the time of 

the invention, the district court must then conduct 

a legal analysis: whether a skilled artisan would 

ascribe that same meaning to that term in the 

context of the specific patent claim under review. 

Id. Experts may explain terms of art and the state of the 

art at any given time, but they cannot be used to prove 

the legal construction of a writing. Id. If a district court 

resolves a subsidiary factual dispute, it will then interpret 

the patent claim in light of the facts as the court found 

them. Id. As the Court cautioned, an “issue does not lose 

its factual character merely because its resolution is 

dispositive of the ultimate legal question.” Id. at 842 

(citations and quotation marks omitted). Regardless of 

whether a subsidiary factual finding plays a small or 

large role in the ultimate conclusion about the meaning of 

the patent term, “the ultimate question of construction 

will remain a legal question.” Id. at 841–42. 

The Court vacated our decision, concluding that Teva 

identified at least one factual finding by the district court 

which we did not review for clear error. Appellants had 

argued that “molecular weight” could not mean Mp beCase: 12-1569 Document: 12-1 Page: 7 Filed: 06/18/2015
8 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

cause the molecular weight values in the Figure 1 legend 

did not match up with the peak values on the Figure 1 

curves. The Supreme Court concluded that the district 

court’s finding “about how a skilled artisan would understand the way in which a curve created from chromatogram data reflects molecular weights” was a factual 

finding. Id. at 843. Distinguishing between the factual 

and legal components of the analysis, the Court explained 

that “[b]ased on that factual finding, the District Court 

reached the legal conclusion that figure 1 did not undermine Teva’s argument that molecular weight referred to 

the first method of calculation (peak average molecular 

weight).” Id. The Court vacated our decision instructing 

that the district court fact findings should be reviewed for 

clear error. Id. The Court acknowledged that Teva 

claimed there were two additional instances in which the 

Federal Circuit rejected fact findings without finding 

clear error. Expressing no opinion on those arguments, 

the Court left these matters for us to consider. Id. 

While Teva was pending at the Supreme Court, the 

Court issued its opinion in Nautilus II. In Nautilus II, 

the Court evaluated our standards for indefiniteness 

under 35 U.S.C. § 112, ¶ 2 (2006),4 rejecting our “not 

amenable to construction or insolubly ambiguous” standard. Those standards were the ones applied in our Teva 

decision. The Supreme Court articulated the standard to 

be applied: “[W]e hold that a patent is invalid for indefiniteness if its claims, read in light of the specification 

delineating the patent, and the prosecution history, fail to 

4 Paragraph 2 of 35 U.S.C. § 112 was replaced with 

newly designated § 112(b) when § 4(c) of the Leahy–Smith 

America Invents Act (“AIA”), Pub. L. No. 112–29, took 

effect on September 16, 2012. Because this case was filed 

before that date, we will refer to the pre-AIA version of § 

112.

 

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inform, with reasonable certainty, those skilled in the art 

about the scope of the invention.” Nautilus II, 134 S. Ct. 

at 2124 (emphasis added). As we explained on remand, 

“[t]he Court has accordingly modified the standard by 

which lower courts examine allegedly ambiguous claims; 

we may now steer by the bright star of ‘reasonable certainty,’ rather than the unreliable compass of ‘insoluble 

ambiguity.’” Biosig Instruments, Inc. v. Nautilus, Inc., 

No. 2012-1289, slip op. at 8 (Fed. Cir. Apr. 27, 2015). 

We therefore reconsider the district court’s claim construction and indefiniteness determination in light of the 

Supreme Court’s guidance. 

DISCUSSION

A patent’s specification must “conclude with one or 

more claims particularly pointing out and distinctly 

claiming the subject matter which the applicant regards 

as [the] invention” 35 U.S.C. § 112, ¶ 2. A patent is 

indefinite “if its claims, read in light of the specification 

delineating the patent, and the prosecution history, fail to 

inform, with reasonable certainty, those skilled in the art 

about the scope of the invention.” Nautilus II, 134 S. Ct. 

at 2124. The definiteness requirement must take into 

account the inherent limitations of language. “Some 

modicum of uncertainty . . . is the ‘price of ensuring the 

appropriate incentives for innovation.’” Id. at 2128 (quoting Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 

535 U.S. 722, 732 (2002)). On the other hand, “a patent 

must be precise enough to afford clear notice of what is 

claimed, thereby appris[ing] the public of what is still 

open to them.” Id. at 2129 (internal quotation marks and 

citations omitted). Indefiniteness is a question of law that 

we review de novo. Wellman, Inc. v. Eastman Chem. Co., 

642 F.3d 1355, 1365–66 (Fed. Cir. 2011). 

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10 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

To determine whether the Group I claim at issue is 

indefinite, we look to the patent record—the claims, 

specification, and prosecution history—to ascertain if they 

convey to one of skill in the art with reasonable certainty

the scope of the invention claimed. We conclude in this 

case that they do not convey with reasonable certainty the 

measure of molecular weight to be used. Claim 1 of the 

’808 patent recites “molecular weight” without specifying 

the meaning of that term. The parties agree that “molecular weight” could refer to Mp, Mw, or Mn. And they agree 

that each of these measures is calculated in a different 

way and would typically yield a different result for a 

given polymer sample. But the claim on its face offers no 

guidance on which measure of “molecular weight” the 

claims cover. 

There is no express definition of “molecular weight” in 

the ’808 patent specification. Nowhere in the specification 

are the terms Mp, Mw, or Mn used. Neither party argues 

to the contrary. Instead, in its supplemental briefing to 

this court, Teva argues that: 

The factual findings establish that to a skilled artisan, ‘average molecular weight’ has a presumed 

meaning in this context, which means that the patent’s specification resolves any ambiguity; that 

the presumed meaning is consistent with Figure 1 

of the specification; and that the only statement 

causing ambiguity in the prosecution history was 

an error. . . . And no intrinsic evidence defeats 

that definite meaning—not Figure 1, and not the 

prosecution history.

Appellees’ Supp. Br. 1; see also id. at 4–7 (Section 2. 

Heading: “The District Court Did Not Clearly Err in 

Finding That The Key Term Has A Presumed Meaning In 

The Art”). Teva’s recitation of what was found below is 

inaccurate. The district court did not find that the term 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC . 11

molecular weight or average molecular weight had a 

presumed meaning in the art. And if there were such a 

finding, it would not have been supported by the record in 

this case. All parties agree that the term “molecular 

weight” or “average molecular weight” in the Group I 

claims could refer to any of the three weight measures Mp, 

Mn, or Mw. Even Teva’s expert Dr. Grant repeatedly 

admitted that the term molecular weight has no default 

meaning to one of skill in the art. J.A. 3096-97. And 

while it is true that the district court used the word 

“presumed” once in its indefiniteness section, the use was

in characterizing Teva’s argument, not in making a fact 

finding: “Thus, Teva (and Dr. Grant) conclude, Mp can be 

read from the chromatogram generated by SEC without 

any ‘further calculation’ and would be understood by a 

person of ordinary skill in the art to be the presumed 

meaning of [average molecular weight] in the context of 

the patents-in-suit.” Markman Order at 588. 

The district court’s determination about how a skilled 

artisan would understand the way in which SECgenerated chromatogram data reflects molecular weight is 

a question of fact. And we see no clear error in that fact 

finding—that one of skill in the art could read Mp from a 

chromatogram without further calculation and that Mw or 

Mn would both require further calculations. We see no 

clear error in the district court’s decision to credit Dr. 

Grant’s testimony that Figure 1 was created by transforming data from a chromatogram to the curves depicted 

in Figure 1. Nor do we see clear error in its acceptance of 

Dr. Grant’s opinion that a person of ordinary skill would 

understand that the process of transforming such data 

could cause the peaks of each curve to shift slightly such 

that a person of skill would understand that the listed 

molecular weights fall approximately at the peaks of the 

curves, i.e., Mp. While Dr. Grant’s argument that the 

peak positions on the curves are within a margin of error

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12 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

(which he admits is as high as an error of 16.7%) is relatively cursory and unexplained, see J.A. 1016–17, nonetheless we do not find the district court’s reliance on it

clearly erroneous. But accepting these fact findings does 

not, as Teva suggests, mean that there now exists a 

presumption regarding the meaning of the claim term in 

the art in general or in the context of this patent. 

To the extent that Teva argues that the meaning of 

“molecular weight” in the context of patents-in-suit is 

itself a question of fact, it is wrong. See Teva, 135 S. Ct. 

at 841–42. A party cannot transform into a factual matter the internal coherence and context assessment of the 

patent simply by having an expert offer an opinion on it. 

The internal coherence and context assessment of the 

patent, and whether it conveys claim meaning with 

reasonable certainty, are questions of law. The meaning 

one of skill in the art would attribute to the term molecular weight in light of its use in the claims, the disclosure 

in the specification, and the discussion of this term in the 

prosecution history is a question of law. The district court 

should not defer to Dr. Grant’s ultimate conclusion about 

claim meaning in the context of this patent nor do we 

defer to the district court on this legal question. To the 

extent that Teva argues that this ultimate determination 

deserves deference, it is in error. To the extent that Teva 

or the dissent suggests that the specification’s disclosure 

of SEC would “infer” that this claim term, molecular 

weight, in this patent refers to Mp, such an inference is 

part of the legal analysis, not a fact finding to be given 

deference. Determining the meaning or significance to 

ascribe to the legal writings which constitute the intrinsic 

record is legal analysis. The Supreme Court made clear 

that the factual components include “the background 

science or the meaning of a term in the relevant art 

during the relevant time period.” Id. at 841. Teva cannot 

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cance of the intrinsic evidence into a factual question 

simply by having an expert testify on it. Id. at 841 (“experts may be examined to explain terms of art, and the 

state of the art, at any given time, but they cannot be 

used to prove the proper or legal construction of any 

instrument of writing” (citation omitted)). Determining 

the significance of disclosures in the specification or 

prosecution history is also part of the legal analysis. 

Understandings that lie outside the patent documents 

about the meaning of terms to one of skill in the art or the 

science or state of the knowledge of one of skill in the art 

are factual issues. Even accepting as correct the district 

court’s factual determinations about SEC and the transfer 

of chromatogram data to create Figure 1, these facts do

not resolve the ambiguity in the Group I claim about the 

intended molecular weight measure. 

To determine whether one of skill in the art would be 

reasonably certain that the claim’s use of molecular 

weight is Mp, we consider as well the prosecution history. 

Statements made during prosecution history are relevant 

to claim construction. See Teva, 135 S. Ct. at 841; Phillips v. AWH Corp., 415 F.3d 1303, 1317 (Fed. Cir. 2005). 

Applicants can define (lexicography), explain, or disavow

claim scope during prosecution. And whether their 

statements or disclaimers impact the meaning of a claim 

term in a given patent is a legal question, not a factual 

one. A statement made during prosecution of related 

patents may be properly considered in construing a term 

common to those patents, regardless of whether the 

statement pre- or post-dates the issuance of the particular 

patent at issue. Microsoft Corp. v. Multi-Tech Sys., Inc., 

357 F.3d 1340, 1350 (Fed. Cir. 2004). The parties do not 

point to any portion of the ’808 patent’s prosecution 

history that is relevant to the construction of “molecular 

weight.” However, they point to, and the district court 

considered, statements about the meaning of “molecular 

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14 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

weight” made during the prosecution of the ’847 and ’539 

patents which are both continuations of the ’808 patent.5 

Such statements are legally relevant to the meaning one 

of skill in the art would attribute to the identical term in 

the ‘808 patent. In the prosecution of both patents, the 

examiner rejected the claims as indefinite because the 

term average molecular weight was meaningless without 

specifying whether Mp, Mn, or Mw should be used. See

J.A. 3220 (“The term ‘average’ molecular weight . . . is 

meaningless as a limitation without specifying its basis, 

e.g. weight average molecular weight, number average 

molecular weight, etc.”); J.A. 3245 (“[T]he term ‘average 

molecular weight’ . . . is indefinite since its method of 

measurement is not specified, i.e. number average molecular weight, weight average molecular weight, average 

molecular weight as determined by light scattering, etc.”). 

The ’808, ’847, and ’539 patents share a nearly identical 

specification, and all three patents identically include 

Example 1 and Figure 1, discussed above. That these 

applications containing the same Example 1 and Figure 1 

as the ’808 patent were rejected for indefiniteness suggests that, contrary to Teva’s position, the specification 

does not conclusively establish that in the context of these 

patents a person of ordinary skill in the art would conclude that the meaning of “molecular weight” is Mp. 

5 Prior to the expiration of the other patents-in-suit, 

Teva did not dispute the relevance of the prosecution 

history of related patents to the construction of the term 

“molecular weight.” See Markman Order at 592; J.A. 

1018. Now Teva argues that “the prosecution history of 

later patents . . . cannot override the specification or 

invalidate the patent.” Appellees’ Supp. Br. 1; see also id.

at 12. But we have said before, and reaffirm today, that 

past and future prosecution of related patents may be 

relevant to the construction of a given claim term. 

 

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In response to the indefiniteness rejection concerning 

the meaning of “molecular weight” during the prosecution 

of the ’847 patent, the earlier of the two continuations, the 

applicants argued that the term “molecular weight” was 

not indefinite because “[o]ne of ordinary skill in the art 

could understand that kilodalton units implies a weight 

average molecular weight,” i.e., Mw. J.A. 3229. To be 

clear, this was the only basis which the applicant argued 

in response to the indefiniteness rejection. And the 

applicant was successful. Defining “molecular weight” as 

Mw, as the applicant did in response to the rejection, was 

what overcame the rejection. The district court heard 

testimony that the statement made during the prosecution of the ’847 patent was scientifically erroneous because each type of “molecular weight” can be expressed in 

kilodaltons. Markman Order at 592. The fact finding by 

the district court—that one of skill in the art would understand that each type of “molecular weight” could be 

expressed in kilodaltons—is not clearly erroneous. However, the fact that Mw, Mn, and Mp can each be expressed 

in kilodaltons does not erase the confusion created by the 

patentee about its claim scope. Regardless of the scientific accuracy of the statement, a person of ordinary skill 

in the art would have understood that the applicants 

defined the term “molecular weight” as Mw to gain allowance of the claims. This is a legal conclusion unaffected 

by the scientific error made during prosecution. To the 

extent that the dissent claims that the significance to be 

given to the patentee’s express definition of molecular 

weight as Mw, made to overcome a rejection, is a question 

of fact, the dissent is wrong. The determination of the 

significance of statements made during prosecution to the 

claim construction is a question of law. 

The examiner required the applicants to provide a 

meaning for “molecular weight” and they provided one: 

Mw. The fact that their explanation contained further 

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16 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

elaboration which itself included a scientific error does 

not undermine the statement’s legal import. “The public 

notice function of a patent and its prosecution history 

requires that a patentee be held to what he declares 

during the prosecution of his patent.” Springs Window 

Fashions LP v. Novo Indus., L.P., 323 F.3d 989, 995 (Fed. 

Cir. 2003). We have held patentees to statements containing errors made during prosecution where, for example, nothing in the statement was at odds with the plain 

language of the claims or the specification. See id. at 

995–96; see also Hockerson-Halberstadt, Inc. v. Avia Grp. 

Int’l, Inc., 222 F.3d 951, 957 (Fed. Cir. 2000) (rejecting 

patentee’s “request for a mulligan that would erase from 

the prosecution history the inventor’s disavowal of a 

particular aspect of a claim term’s meaning” despite 

patentee’s argument that a person of ordinary skill would 

have understood the statement during prosecution to be 

erroneous); cf. Biotec Biologische Naturverpackungen 

GmbH v. Biocorp, Inc., 249 F.3d 1341, 1348 (Fed. Cir. 

2001) (declining to limit claims by erroneous statement 

made during prosecution that was contrary to the plain 

language of the claims, the specification, and other statements made during prosecution). Given the role of the 

statement in gaining allowance of the claims, a person of 

ordinary skill in the art would have understood the applicants to have defined “molecular weight” to mean Mw, and 

the fact that any of the measures (Mw, Mn or Mp) can be 

expressed in kilodaltons, does not change the significance 

of the choice made by the patentee, Mw, to overcome the 

rejection. And importantly, this determination is part of 

the legal analysis, not as the dissent claims, one of the 

fact findings to which we owe deference. 

During the prosecution of the ’539 patent, the applicants responded to a nearly identical indefiniteness 

rejection to the term “molecular weight” by arguing that a 

person “of ordinary skill in the art, upon reviewing the 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC . 17

specification, would understand that ‘average molecular 

weight’ refers to the molecular weight at the peak of the 

molecular distribution curve in Figure 1,” i.e., Mp. J.A. 

3258. Here too the specification was identical to the ’808 

and ’847 patents in all respects relevant to the molecular 

weight question, and the examiner found the specification 

did not provide the reasonable certainty required for 

definiteness. The patentee overcame that rejection by 

again defining which measure of molecular weight to use, 

in that case Mp. 

To summarize, it is undisputed that “molecular 

weight” or average molecular weight can be ascertained 

by any of three possible measures: Mp, Mn, and Mw. The 

claims do not indicate which measure to use. The specification never defines molecular weight or even mentions 

Mp, Mw, or Mn. And the term “average molecular weight” 

does not have a plain meaning to one of skill in the art. 

The district court fact findings regarding how one of skill 

in the art would understand the way in which a curve 

created with chromatogram data reflects molecular 

weights was not clearly erroneous. Its fact findings about 

the additional calculations that would be required to 

determine Mw or Mn are not clearly erroneous. Its fact 

findings about how a skilled artisan would accept a curve 

“shift” when converting chromatogram data to a curve 

such as that illustrated in Figure 1 are not clearly erroneous. A skilled artisan, knowing a shift might occur, would 

still not be reasonably certain in light of the entire record 

as to which type of average was intended. During prosecution of the related ’847 and ’539 patents, which with 

respect to molecular weight have identical specifications, 

examiners twice rejected the term “molecular weight” as 

indefinite for failing to disclose which measure of molecular weight to use (Mp, Mn, or Mw). And the patentee in 

one instance stated that it was Mw and in the other stated 

it was Mp. We find no clear error in the district court’s 

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18 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

fact finding that one of the statements contained a scientifically erroneous claim. We hold that claim 1 is invalid 

for indefiniteness by clear and convincing evidence because read in light of the specification and the prosecution 

history, the patentee has failed to inform with reasonable 

certainty those skilled in the art about the scope of the 

invention. On this record, there is not reasonable certainty that molecular weight should be measured using Mp. 

This is the legal question—and on this question—we 

reverse the district court. 

AFFIRMED-IN-PART, REVERSED-IN-PART

COSTS

No costs.

Case: 12-1569 Document: 12-1 Page: 18 Filed: 06/18/2015
United States Court of Appeals 

for the Federal Circuit ______________________ 

 

TEVA PHARMACEUTICALS USA, INC.,

TEVA PHARMACEUTICAL INDUSTRIES, LTD., 

TEVA NEUROSCIENCE, INC., YEDA RESEARCH 

AND DEVELOPMENT CO., LTD.,

Plaintiffs-Appellees

v.

SANDOZ, INC., MOMENTA PHARMACEUTICALS 

INC.,

Defendants-Appellants

MYLAN PHARMACEUTICALS INC., MYLAN INC., 

NATCO PHARMA LTD.,

Defendants-Appellants

SANDOZ INTERNATIONAL GMBH, 

NOVARTIS AG,

Defendants

______________________ 

2012-1567, 2012-1568, 2012-1569, 2012-1570

______________________ 

MAYER, Circuit Judge, dissenting.

“[I]n some instances, a factual finding may be close to 

dispositive of the ultimate legal question of the proper 

meaning of [a claim] term in the context of [a] patent.” 

Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 

841–42 (2015). This is such a case. After carefully evaluating the testimony of the parties’ experts, the district 

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2 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

court made a factual finding that an artisan skilled in the 

art of polypeptide synthesis would have inferred from the 

use of an analytic technique known as size exclusion 

chromatography (“SEC”) in U.S. Patent No. 5,800,808 (the 

“’808 patent”) that the term “molecular weight” referred 

to peak average molecular weight. Teva Pharm. USA, 

Inc. v. Sandoz Inc., 810 F. Supp. 2d 578, 588 (S.D.N.Y. 

2011) (“District Court Decision”). The court further found 

that a person of ordinary skill in the art would have 

accepted a statement made by the patentee during prosecution of U.S. Patent No. 6,939,539 (the “’539 patent”) as 

“proof” of what was meant by the term “molecular 

weight.” Id. at 592.* Because neither of these factual 

findings is clearly erroneous, we are not free to disregard 

or discount them in assessing whether the ’808 patent 

withstands definiteness scrutiny. See Pullman-Standard 

v. Swint, 456 U.S. 273, 287 (1982) (emphasizing that 

Federal Rule of Civil Procedure 52(a) “does not make 

exceptions or purport to exclude certain categories of 

factual findings from the obligation of a court of appeals 

to accept a district court’s findings unless clearly erroneous”). I therefore respectfully dissent. 

I.

In some cases, a trial court can decide an indefiniteness dispute based solely on the intrinsic evidence. When 

a district court’s review is confined to the intrinsic record, 

its conclusion on indefiniteness will be a legal determination which we can appropriately review de novo. See 

Teva, 135 S. Ct. at 841. In many instances, however, 

* Teva Pharmaceuticals USA, Inc. and related parties (collectively “Teva”) own the ’808 patent, which is the 

sole patent at issue in this appeal. The ’808 patent is 

related to both the ’539 patent and U.S. Patent No. 

6,620,847 (the “’847 patent”), and the three patents share 

substantially identical specifications.

 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC. 3

particularly where complex technology is at issue, a trial 

court will be required to look outside a patent and its 

prosecution history in order to fully apprehend matters 

such as “the background science or the meaning of a term 

in the relevant art during the relevant time period.” Id.; 

see Seymour v. Osborne, 78 U.S. 516, 546 (1871) (emphasizing that a patent may be “so interspersed with technical terms and terms of art that the testimony of 

scientific witnesses is indispensable to a correct understanding of its meaning”). Those laboring in different 

fields of scientific endeavor often speak with words drawn 

from specialized lexicons, and in many cases it is only by 

delving into the background science and thoroughly 

evaluating the testimony of competing experts that a trial 

court can make an informed determination as to whether 

a claim provides a skilled artisan with reasonable certainty as to the scope of an invention. See Loom Co. v. Higgins, 105 U.S. 580, 585 (1881) (explaining that skilled 

artisans “understand the language of their brother scientist[s]”).

The court here is once again led astray by its failure 

to afford sufficient deference to the trial court’s findings of 

fact. See Teva, 135 S. Ct. at 842. The district court 

engaged in extensive fact-finding about the background 

science reflected in the ’808 patent. See id. at 840 (“[T]his 

case provides a perfect example of the factfinding that 

sometimes underlies claim construction: The parties here 

presented the District Court with competing fact-related 

claims by different experts, and the District Court resolved the issues of fact that divided those experts.”). 

After considering expert declarations and deposition 

testimony—and holding two hearings—the court determined that the term “molecular weight” was not indefinite because a skilled artisan would have understood its 

meaning. See District Court Decision, 810 F. Supp. 2d at 

587–95. Relying in significant measure on the testimony 

of Dr. Gregory Grant, Teva’s expert, the trial court made 

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4 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

three key factual determinations: (1) a person of ordinary 

skill in the art of polypeptide synthesis would infer from 

the use of the SEC method disclosed in the specification of 

the ’808 patent that the term “molecular weight” referred 

to peak average molecular weight, id. at 589–90; (2) a 

skilled artisan would not rely upon a statement Teva 

made when prosecuting the ’847 patent that the expression of molecular weight in kilodalton units “implie[d] a 

weight average molecular weight,” because that statement rested on obvious scientific error, id. at 591–92; and 

(3) that artisan would instead rely on Teva’s affirmative 

statement, made while prosecuting the ’539 patent, that 

“molecular weight” meant peak average molecular weight, 

id. at 592.

We must be “mindful that we are a court of review, 

not of first view,” Cutter v. Wilkinson, 544 U.S. 709, 718 

n.7 (2005), and that our duty is to evaluate each case in 

light of the facts as the trial court has found them. This 

court’s conclusion that the ’808 patent is fatally indefinite 

hinges on the fact that Teva made divergent statements 

as to the meaning of “molecular weight” when prosecuting 

the ’847 and ’539 patents. Ante at 17. That conclusion, 

however, cannot be reconciled with the district court’s 

express factual finding that a skilled artisan would not 

rely on the statement Teva made as to the meaning of 

“molecular weight” when prosecuting the ’847 patent 

because it was scientifically incorrect. Peak average 

molecular weight, weight average molecular weight, and 

number average molecular weight are all expressed in 

kilodaltons. See District Court Decision, 810 F. Supp. 2d 

at 592. Accordingly, Teva’s statement that the use of 

kilodalton units implied that “molecular weight” meant 

weight average molecular weight was a non sequitur and, 

as the district court correctly found, a skilled artisan 

would not have relied upon it. See id. 

As this court has repeatedly made clear, obviously erroneous statements in the prosecution file carry little 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC. 5

weight in determining claim meaning. See, e.g., Rambus 

Inc. v. Infineon Techs. AG, 318 F.3d 1081, 1090 (Fed. Cir. 

2003) (emphasizing that an “incorrect statement in the 

prosecution history [did] not govern the meaning of the 

claims”); Biotec Biologische Naturverpackungen GmbH v. 

Biocorp, Inc., 249 F.3d 1341, 1348 (Fed. Cir. 2001) (“An 

error in the prosecution record must be viewed as are 

errors in documents in general; that is, would it have been 

apparent to the interested reader that an error was made, 

such that it would be unfair to enforce the error.”). Furthermore, a single statement by Teva during prosecution 

of the ’847 patent—made years after the ’808 patent 

issued—should not be deemed dispositive on the question 

of whether the ’808 patent is sufficiently definite. See

Athletic Alternatives, Inc. v. Prince Mfg., Inc., 73 F.3d 

1573, 1580 (Fed. Cir. 1996) (emphasizing that the ambiguity of the prosecution history made it “unhelpful as an 

interpretive resource” for determining the meaning of a 

claim term). While the prosecution history of one patent 

in a chain may be used to construe the same term in both 

earlier and later issued related patents with the same 

specification, see Microsoft Corp. v. Multi-Tech Sys., Inc., 

357 F.3d 1340, 1350 (Fed. Cir. 2004), the court is unable 

to cite to a single case in which a statement made in 

prosecuting a later related patent was deemed sufficient, 

standing alone, to render an earlier issued patent indefinite. The prosecution history of the ’847 patent cannot 

trump the disclosure in the specification of the ’808 patent 

which, by describing the use of the SEC method, indicates 

to a skilled artisan that “molecular weight” means peak 

average molecular weight. See Vederi, LLC v. Google, 

Inc., 744 F.3d 1376, 1382 (Fed. Cir. 2014) (emphasizing 

that “the specification is the single best guide to the 

meaning of a claim term” and that “the prosecution history often lacks the clarity of the specification” (citations 

and internal quotation marks omitted)). 

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6 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

According to the court, although Teva’s statement 

that the use of kilodalton units “implie[d] a weight average molecular weight” was scientifically incorrect, a 

skilled artisan would nonetheless have understood that 

the applicants defined the term “molecular weight” as 

weight average molecular weight to gain allowance of the 

claims. Ante at 16. This argument is unconvincing. Read 

as a whole, Teva’s statement that the use of kilodalton 

units “implie[d] a weight average molecular weight” is 

nonsensical, and a skilled artisan would not rely upon any 

part of it. This is particularly true given that Teva confirmed, when subsequently prosecuting the ’539 patent, 

that—consistent with the use of the SEC method disclosed in the specification—the term “molecular weight” 

meant peak average molecular weight. See Elbex Video, 

Ltd. v. Sensormatic Elecs. Corp., 508 F.3d 1366, 1372–73 

(Fed. Cir. 2007) (concluding that an earlier, incorrect 

statement in the prosecution history did not override a 

later, correct statement as to claim scope).

In assessing obviousness, what the prior art teaches is 

a question of fact. See Graham v. John Deere Co., 383 

U.S. 1, 17 (1966); see also Lighting Ballast Control LLC v. 

Philips Elecs. N. Am. Corp., 744 F.3d 1272, 1307 (Fed. 

Cir. 2014) (en banc) (O’Malley, J., dissenting), judgment 

vacated sub nom. Lighting Ballast Control LLC v. Universal Lighting Techs., Inc., 135 S. Ct. 1173 (2015) (“Importantly, one of the key fact questions in an obviousness 

inquiry is what a prior art reference teaches—often, what 

is claimed and described in a previously issued patent. 

And, all findings regarding the scope and content of the 

prior art are subject to clear error review.” (citation omitted)). In assessing indefiniteness, likewise, a trial court’s 

determination, based on expert testimony, as to what a 

skilled artisan would glean from subsequently issued 

patents and their prosecution histories is a factual finding 

which can be set aside only for clear error. See Bose Corp. 

v. Consumers Union of U.S., Inc., 466 U.S. 485, 498 (1984) 

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TEVA PHARMACEUTICALS USA v. SANDOZ INC. 7

(“It surely does not stretch the language of [Rule 52(a)] to 

characterize an inquiry into what a person knew at a 

given point in time as a question of ‘fact.’” (footnote omitted)). We cannot substitute our assessment of the testimony for that of the trial court simply because from our 

appellate perch we might assess that testimony differently. If we credit—as we must because it is not clearly 

erroneous—the district court’s explicit finding that a 

skilled artisan would not rely on the facially incorrect 

statement made during prosecution of the ’847 patent, 

there is no reasonable basis for concluding that the prosecution history of patents related to the ’808 patent would 

create, in the mind of the skilled artisan, ambiguity 

regarding the meaning of the term “molecular weight.”

The court’s approach here contravenes binding precedent. In Enzo Biochem Inc. v. Applera Corp., we held that 

under Teva a trial court’s conclusion, based on expert 

testimony, as to whether an example in the specification 

disclosed “direct detection” was a “factual finding” which 

was subject to clear error review. 780 F.3d 1149, 1156 

(Fed. Cir. 2015). Likewise, in EON Corp. IP Holdings 

LLC v. AT&T Mobility LLC, we held that a district court’s 

determination, based on the testimony from experts, that 

claims disclosed “complicated, customized computer software” was a “factual finding[].” 785 F.3d 616, 624 (Fed. 

Cir. 2015). Here, however, the court insists that the 

determination, based on extensive expert testimony, that 

a skilled artisan would not rely on a facially incorrect 

statement made during prosecution of the ’847 patent was 

“part of the legal analysis, not as the dissent claims, one 

of the fact findings to which we owe deference.” Ante at 

16. The court’s view that the universe of factual findings 

to which we owe deference includes only 

“[u]nderstandings that lie outside the patent documents,” 

ante at 13, simply cannot be squared with Enzo and EON. 

Although the ultimate conclusion of indefiniteness 

under 35 U.S.C. § 112 is a legal question, see Eidos DisCase: 12-1569 Document: 12-1 Page: 25 Filed: 06/18/2015
8 TEVA PHARMACEUTICALS USA v. SANDOZ INC. 

play, LLC v. AU Optronics Corp., 779 F.3d 1360, 1364-65 

(Fed. Cir. 2015), Teva mandates that the trial court’s 

factual findings are to be respected, barring clear error, 

and that the required legal analysis must be performed in 

view of those findings, 135 S. Ct. at 841. Here, however, 

the court takes the opposite tack, first embarking on an 

independent review of the record and then considering, as 

an afterthought, the important and carefully considered 

factual findings made by the trial court.

II.

In Nautilus, Inc. v. Biosig Instruments, Inc., the Supreme Court rejected this court’s view that a claim met 

definiteness requirements so long as it was “amenable to 

construction,” and, as construed, was not “insolubly 

ambiguous.” 134 S. Ct. 2120, 2124 (2014) (citations and 

internal quotation marks omitted). Because the district 

court here relied on the now discarded “insolubly ambiguous” standard when it held that the ’808 patent was not 

invalid for indefiniteness, see District Court Decision, 810 

F. Supp. 2d at 582, this case should be remanded so that 

the court can take additional evidence as it deems appropriate and assess in the first instance whether the ’808 

patent meets the more stringent Nautilus definiteness 

standard. See 134 S. Ct. at 2124 (explaining “that a 

patent is invalid for indefiniteness if its claims, read in 

light of the specification delineating the patent, and the 

prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the 

invention”).

The ’808 patent will expire in September 2015. This 

looming expiration date does not, however, permit us to 

overstep our appellate role or feign first-hand experience 

with the testimony or the technology. We are neither 

equipped nor authorized to make the predicate factual 

determinations necessary to assess whether the ’808 

patent withstands definiteness scrutiny under the NautiCase: 12-1569 Document: 12-1 Page: 26 Filed: 06/18/2015
TEVA PHARMACEUTICALS USA v. SANDOZ INC. 9

lus standard. See Anderson v. Bessemer City, 470 U.S. 

564, 574 (1985) (emphasizing that “[t]he trial judge’s 

major role is the determination of fact, and with experience in fulfilling that role comes expertise”).

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