United States Court of Appeals 

for the Federal Circuit ______________________ 

AMGEN INC., AMGEN MANUFACTURING 

LIMITED, AMGEN USA, INC.,

Plaintiffs-Appellees

v.

SANOFI, AVENTISUB LLC, REGENERON 

PHARMACEUTICALS INC., SANOFI-AVENTIS U.S., 

LLC,

Defendants-Appellants

______________________ 

2017-1480

______________________ 

Appeal from the United States District Court for the 

District of Delaware in Nos. 1:14-cv-01317-SLR, 1:14-cv01349-SLR, 1:14-cv-01393-SLR, 1:14-cv-01414-SLR, 

Judge Sue L. Robinson.

______________________ 

Decided: October 5, 2017

______________________ 

 DARYL JOSEFFER, King & Spalding LLP, Washington, 

DC, argued for plaintiffs-appellees. Also represented by 

CHRISTOPHER ROBERT HEALY, JOSHUA NATHANIEL 

MITCHELL; MERRITT ELLEN MCALISTER, Atlanta, GA; 

KATHERINE NICOLE CLOUSE, SARAH CHAPIN COLUMBIA, 

McDermott, Will & Emery LLP, Boston, MA; WILLIAM G.

GAEDE, III, Menlo Park, CA; ERIC W. HAGEN, Los Angeles, 

CA; EMILY CURTIS JOHNSON, ERICA S. OLSON, DENNIS J.
2 AMGEN INC. v. SANOFI

SMITH, STEVEN D. TANG, STUART L. WATT, WENDY A.

WHITEFORD, Amgen Inc., Thousand Oaks, CA; 

CHRISTOPHER MEAD, London & Mead, Washington, DC; 

MELANIE K. SHARP, Young, Conaway, Stargatt & Taylor 

LLP, Wilmington, DE.

 PAUL D. CLEMENT, Kirkland & Ellis LLP, Washington, 

DC, argued for defendants-appellants. Also represented 

by GEORGE W. HICKS, JR., NATHAN S. MAMMEN; SIEW YEN 

CHONG, VISHAL C. GUPTA, JOHN J. MOLENDA, Steptoe & 

Johnson, LLP, New York, NY; RICHARD PRASEUTH, Los 

Angeles, CA; KILEY ANN WHITE, Washington, DC.

 DUANE CHRISTOPHER MARKS, Eli Lilly and Company, 

Indianapolis, IN, for amicus curiae Eli Lilly and Company. Also represented by GREGORY ALAN COX, GILBERT 

VOY, ALEXANDER WILSON. 

 BARBARA ANNE JONES, AARP Foundation Litigation, 

Pasadena, CA, for amici curiae AARP and AARP Foundation.

 DIMITRIOS T. DRIVAS, White & Case LLP, New York, 

NY, for amicus curiae Pfizer Inc. Also represented by ERIC 

M. MAJCHRZAK, AMIT THAKORE; JEFFREY NEIL MYERS, 

Pfizer Inc., New York, NY.

 DAVID A. KELLY, Hunton & Williams LLP, Atlanta, 

GA, for amicus curiae Ipsen Pharma S.A.S.

 MELISSA ARBUS SHERRY, Latham & Watkins LLP, 

Washington, DC, for amicus curiae AbbVie Inc. Also 

represented by MICHAEL A. MORIN, EMILY K. SAUTER. 

 WILLIAM MARSILLO, Boies, Schiller & Flexner, LLP, 

Armonk, NY, for amici curiae Luis Aparicio, M.D., W. 

Ross Davis, M.D., Avichai Eres, M.D., Norman Lepor, 

M.D., Mary McGowan, M.D., Narendra Singh, M.D., Paul 
AMGEN INC. v. SANOFI 3

Thompson, M.D., Rosa DeBernardo, Alina Wilson. Also 

represented by MICHAEL JAY, Santa Monica, CA.

______________________ 

Before PROST, Chief Judge, TARANTO and HUGHES,

Circuit Judges.

PROST, Chief Judge. 

Appellants Sanofi, Aventisub LLC, Regeneron Pharmaceuticals Inc., and Sanofi-Aventis U.S., LLC (collectively, “Appellants”) appeal from a final judgment of the 

district court holding U.S. Patent Nos. 8,829,165 (“’165 

patent”) and 8,859,741 (“’741 patent”) not invalid and 

granting a permanent injunction enjoining sales of Appellants’ Praluent® alirocumab (“Praluent”).1 In particular, 

Appellants argue that the district court improperly excluded evidence regarding written description and enablement, improperly instructed the jury on written 

description, improperly denied Appellants’ motion seeking

JMOL of no written description and no enablement, 

improperly granted Appellees’ motion seeking JMOL of 

non-obviousness, and improperly issued the permanent 

injunction. Appellants’ Br. 1. Because we conclude that 

the district court (i) erred by excluding Appellants’ evidence regarding written description and enablement, and

(ii) improperly instructed the jury on written description, 

we reverse-in-part and remand for a new trial on written 

description and enablement. We also conclude that 

Appellants are not entitled to JMOL of no written description and no enablement. We affirm the district 

court’s grant of Appellees’ JMOL of non-obviousness. 

Finally, we vacate the district court’s permanent injunction.

 

1 Appellants stipulated to infringement of the ’165 

and ’741 patents. Appellants’ Br. 11.
4 AMGEN INC. v. SANOFI

I 

A 

The patents at issue generally relate to antibodies 

that help reduce low-density lipoprotein cholesterol (LDLC), or “bad cholesterol.” High levels of LDL-C in the 

bloodstream can cause heart attacks, strokes, and cardiovascular disease. Typically, high LDL-C is treated using 

small molecules called statins. In some cases, however, 

statins have adverse side effects or cannot reduce a patient’s LDL-C to a healthy level, requiring alternative 

treatment. One such alternative treatment is a PCSK9 

inhibitor—the medicine claimed by the patents at issue. 

PCSK9 is a naturally occurring protein that binds to and 

causes the destruction of liver cell receptors (LDL receptors, or LDL-Rs) that are responsible for extracting LDLC from the bloodstream. 

Appellees Amgen Inc., Amgen Manufacturing, Ltd., 

and Amgen USA, Inc. (collectively, “Appellees”) first 

began studying PCSK9 in early 2005. This research 

resulted in the development of Appellees’ drug RepathaTM 

which uses the active ingredient “evolocumab.” Evolocumab is a monoclonal antibody that targets PCSK9 to 

prevent it from destroying LDL-R proteins. Appellees 

filed for FDA approval on August 27, 2014. The FDA 

approved Repatha in August 2015.

The two patents at issue, both of which share the 

same specification, are entitled “Antigen binding proteins 

to proprotein convertase subtilisin kexin type 9 

(PCSK9).”2 The ’165 patent issued on September 9, 2014, 

and the ’741 patent issued on October 14, 2014. The 

patents have an undisputed priority date of January 9, 

2008. Appellants’ Br. 12. The relevant claims cover the 

 

2 All references are to the ’165 patent unless otherwise indicated.
AMGEN INC. v. SANOFI 5

entire genus of antibodies that bind to specific amino acid 

residues on PCSK9 and block PCSK9 from binding to 

LDL-Rs.3 The patents do not specifically claim Repatha, 

or any other antibody, by amino acid sequence. Claim 1 of 

the ’165 patent is representative. It recites:

An isolated monoclonal antibody, wherein, when 

bound to PCSK9, the monoclonal antibody binds 

to at least one of the following residues: S153, 

I154, P155, R194, D238, A239, I369, S372, D374, 

C375, T377, C378, F379, V380, or S381 of SEQ ID 

NO:3, and wherein the monoclonal antibody 

blocks binding of PCSK9 to LDL[-]R.

’165 patent col. 427 ll. 47–53. 

The patents disclose the trial-and-error process Appellees used to generate and screen antibodies that bind to 

PCSK9 and block PCSK9 from binding to LDL-Rs. Id. at 

col. 73 l. 29–col. 124 l. 31. In particular, the specification 

explains that to discover the claimed antibodies, 3,000 

human monoclonal antibodies were “rescreened for binding to wild-type PCSK9 to confirm stab[ility],” id. at col. 

78 ll. 4–6, which were eventually narrowed to “85 antibodies that blocked interaction between the PCSK9 . . . and

the LDLR [at] greater than 90%,” id. at col. 80 ll. 35–37. 

The specification also discloses the three-dimensional 

structures, obtained via x-ray crystallography, of two 

antibodies known to bind to residues recited in the

claims—21B12 (Repatha) and 31H4. Id. at fig. 3E, fig.

3JJ, col. 99 l. 29–col. 103 l. 60. Finally, the specification 

discloses the amino acid sequences of twenty-two other 

antibodies that “bin” with Repatha or 31H4, meaning they 

 

3 A “residue” is a particular amino acid along 

PCSK9’s amino acid sequence. Thus, the residue “S153” 

refers to the amino acid serine, located at the 153rd position of PCSK9’s sequence.
6 AMGEN INC. v. SANOFI

compete with these antibodies for binding to PCSK9. Id.

at figs. 2A–2D, figs. 3A–3JJ, col. 88 l. 30–col. 89 l. 37. 

In September 2007, Appellants also started exploring 

antibodies targeting PCSK9. This research resulted in 

development of Praluent. The active ingredient in 

Praluent is a monoclonal antibody that targets PCSK9 to 

prevent it from binding to and destroying LDL-R proteins. 

The LDL-R proteins then extract LDL-C thereby lowering 

overall LDL-C levels in the bloodstream. In November 

2011, the PTO issued Appellants a patent that claimed 

Praluent by its amino acid sequence. Appellants filed for 

FDA approval of Praluent in November 2014. The FDA 

approved Praluent in July 2015. 

B 

In October 2014, Appellees sued Appellants, claiming 

that Praluent infringed the patents in suit. Appellants 

stipulated to infringement but challenged the patents’

validity on written description, enablement, and obviousness grounds. 

Over the course of litigation, the district court made 

several rulings and decisions that are challenged here on 

appeal. First, the district court excluded all of Appellants’ 

post-priority-date evidence proffered to show that the 

patents in suit did not provide adequate written description. Second, the district court instructed the jury, over 

Appellants’ objection, that written description can be 

satisfied “by the disclosure of a newly-characterized 

antigen . . . if you find that the level of skill and 

knowledge in the art of antibodies at the time of filing was 

such that production of antibodies against such an antigen was conventional or routine.” J.A. 1580. Third, the 

district court denied Appellants’ post-trial motions seeking JMOL on written description and enablement. 

Fourth, the district court excluded two purported prior art 

references, Novartis and Schering, for being improper 

prior art and granted Appellees’ motion seeking JMOL of 
AMGEN INC. v. SANOFI 7

non-obviousness. And fifth, the district court issued a 

permanent injunction removing Appellants’ Praluent from 

the market. 

This court stayed the injunction pending appeal.

II

A 

We first review whether the district court improperly 

excluded Appellants’ evidence about antibodies, including 

Appellants’ infringing Praluent, developed after the 

patents’ priority date of January 9, 2008. Appellants 

proffered this evidence to show that the patents lack 35 

U.S.C. § 112 written description support. The district 

court excluded this evidence, concluding that because the 

evidence did not “illuminate[] the state of the art at the 

time of filing,” it was not relevant “to determine whether 

there is sufficient disclosure of the claimed invention.” 

Amgen Inc. v. Sanofi, No. 14-1317, 2016 WL 675576, at *2 

(D. Del. Feb. 18, 2016); see also J.A. 1030 (“I concluded 

that, because the written description requirement is 

tested as of the filing date, such evidence should be excluded.”). Because the district court’s decision was based 

on a misapplication of the law, we reverse. 

Section 112 states that “[t]he specification shall contain a written description of the invention . . . in such full, 

clear, concise, and exact terms as to enable any person 

skilled in the art to which it pertains . . . to make and use 

the same . . . .” This requirement ensures “that the inventor actually invented the invention claimed.” Ariad 

Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. 

Cir. 2010) (en banc). To show invention, a patentee must 

convey in its disclosure that it “had possession of the 

claimed subject matter as of the filing date.” Id. at 1350. 

Demonstrating possession “requires a precise definition” 

of the invention. Id. To provide this “precise definition” 

for a claim to a genus, a patentee must disclose “a repre-
8 AMGEN INC. v. SANOFI

sentative number of species falling within the scope of the 

genus or structural features common to the members of

the genus so that one of skill in the art can ‘visualize or

recognize’ the members of the genus.” Id. 

Here, the parties dispute whether a court may rely on 

post-priority-date evidence to determine if a patent discloses “a representative number of species.” Id. Appellants argue that because the “written description 

requirement protects against ‘attempts to preempt the 

future before it has arrived,’” Appellants’ Br. 28 (quoting 

Fiers v. Revel, 984 F.2d 1164, 1171 (Fed. Cir. 1993)), it 

“would make [no] sense if future innovators were barred 

from introducing evidence of their own innovations in 

written description challenges,” id. Appellees counter 

that because “[w]ritten description and enablement are 

judged at the time of filing,” Appellees’ Br. 34 (citing 

Ariad, 598 F.3d at 1355), “post-priority-date evidence may 

be relevant only if it illuminates the state of the art at the 

filing date,” id. (first citing In re Koller, 613 F.2d 819, 825 

(CCPA 1980); then citing In re Hogan, 559 F.2d 595, 605 

(CCPA 1977)). And because Praluent and the other 

antibodies Appellants proffered did not exist until after 

the priority date, “they [were] not part of the state of the 

art . . . and therefore cannot ‘illuminate’ it.” Id. 

Appellees are correct that written description is 

judged based on the state of the art as of the priority date. 

Ariad, 598 F.3d at 1355. Accordingly, evidence illuminating the state of the art subsequent to the priority date is 

not relevant to written description. Id. Appellants, 

however, are also correct that a patent claiming a genus 

must disclose “a representative number of species falling 

within the scope of the genus or structural features common to the members of the genus so that one of skill in 

the art can ‘visualize or recognize’ the members of the 

genus.” Id. at 1351. Evidence showing that a claimed 

genus does not disclose a representative number of species may include evidence of species that fall within the 
AMGEN INC. v. SANOFI 9

claimed genus but are not disclosed by the patent, and 

evidence of such species is likely to postdate the priority 

date. If such evidence predated the priority date, it might 

well anticipate the claimed genus.

Here, Appellants sought to introduce evidence not to 

illuminate the state of the art on the priority date but to 

show that the patent purportedly did not disclose a representative number of species. Appellants’ Br. 12. As a 

logical matter, such evidence is relevant to the representativeness question. Simply, post-priority-date evidence of 

a particular species can reasonably bear on whether a 

patent “fails to disclose a representative number of species falling within the scope of the genus or structural 

features common to the members of the genus so that one 

of skill in the art can ‘visualize or recognize’ the members 

of the genus.” Ariad, 598 F.3d at 1350.

We have not ruled on that question to date, but the 

common-sense logic of admissibility finds support in 

AbbVie Deutschland GmbH & Co. v. Janssen Biotech, Inc., 

759 F.3d 1285 (Fed. Cir. 2014). There, Centocor, the

accused infringer of AbbVie’s functional claim to a genus 

of antibodies, stipulated to infringement and challenged 

validity based on written description. Centocor argued 

that the antibodies disclosed in AbbVie’s patents were 

“not representative of the entire genus,” id. at 1298, and it 

relied heavily on its own accused antibody to support the 

unrepresentativeness argument, introducing evidence 

that its antibody “differ[ed] considerably from 

the . . . antibodies described in [the asserted] patents,” id. 

at 1300. The jury found that the patents lacked adequate 

written description, and both the district court and this 

court relied heavily on that evidence in upholding the 

invalidity verdict. See AbbVie, 759 F.3d at 1301; Abbott 

GmBH & Co., KG v. Centocor Ortho Biotech, Inc., 971 

F.3d 171, 176–80 (D. Mass. 2013). That is significant 

because, at the time of trial, the timing of Centocor’s 

antibody in relation to AbbVie’s priority date was unset-
10 AMGEN INC. v. SANOFI

tled: the PTO, in an interference, had found that Centocor’s antibody postdated AbbVie’s invention, as AbbVie 

argued, and the subsequent litigation of the question 

under 35 U.S.C. § 146 was unresolved. See Abbott, 870 F. 

Supp. 2d at 246. The Centocor antibody, in short, was a 

basis for the unrepresentativeness ruling without regard 

to whether it postdated the patent’s priority date.

Appellees argue, and the district court held, that our 

predecessor court’s decision in In re Hogan prohibits the 

use of post-priority-date evidence to show that a patent 

fails to disclose a representative number of species. See 

Appellees’ Br. 34 (“[P]ost-priority-date evidence may be 

relevant only if it illuminates the state of the art at the 

filing date.”); J.A. 1032 (“By giving its imprimatur to the 

jury’s verdict [in AbbVie], the Federal Circuit arguably

departed from its own precedent, established in In re 

Hogan, 559 F.2d 595 (CCPA 1977), that later-developed or 

later-discovered products should not be used to test

compliance with 35 U.S.C. § 112[, ¶] 1.”). But the district 

court and Appellees misread In re Hogan by conflating the 

difference between post-priority-date evidence proffered to 

illuminate the post-priority-date state of the art, which is 

improper, with post-priority-date evidence proffered to 

show that a patent fails to disclose a representative 

number of species. In re Hogan prohibits the former but 

is silent with respect to the latter. 

In In re Hogan, the U.S. Patent and Trademark Office 

(“PTO”) rejected an application directed to “Solid Polymer 

of Olefins” for failing to enable the claimed invention. 559 

F.3d at 597. The relevant claim at issue recited, in its 

entirety, “[a] normally solid homopolymer of 4-methyl-1-

pentene.” Id. The application disclosed “a method of 

making the crystalline form” of the claimed homopolymer

which was “the only then existing way to make such a 

polymer.” Id. at 606. The PTO rejected the application, 

however, because the application did not disclose a second, “amorphous form” of making the polymer “which . . . 
AMGEN INC. v. SANOFI 11

did not exist” as of the priority date. Id. Our predecessor 

court reversed the PTO, holding that “[t]o now say that 

appellants should have disclosed in 1953 the amorphous 

form which on this record did not exist until 1962, would 

be to impose an impossible burden on inventors and thus 

on the patent system.” Id. Further, because the applicant had claimed the homopolymer and not a particular 

method of making the polymer, the court further held that 

“[t]o restrict appellants to the crystalline form disclosed, 

under such circumstances, would be a poor way to stimulate invention, and particularly to encourage its early 

disclosure.” Id.

Here, unlike in In re Hogan, Appellants were not offering post-priority-date evidence to show that Appellees’ 

claimed genus is not enabled because of a change in the 

state of the art. Instead, Appellants offered Praluent and 

other post-priority-date antibodies to argue that the 

claimed genus fails to disclose a representative number of 

species. As explained above, the use of post-priority-date 

evidence to show that a patent does not disclose a representative number of species of a claimed genus is proper. 

It was thus legal error for the district court to categorically preclude all of Appellants’ post-priority-date evidence of 

Praluent and other antibodies. Accordingly, we reverse 

the district court’s decision and remand for a new trial on 

written description. 

For many of the same reasons, the district court’s improper exclusion of post-priority-date evidence requires a 

new trial on enablement as well. Under the enablement 

requirement, “the specification of a patent must teach 

those skilled in the art how to make and use the full scope 

of the claimed invention without undue experimentation.” 

Genentech, Inc. v. Novo Nordisk A/S, 108 F.3d 1361, 1365

(Fed. Cir. 1997). Appellants purportedly sought to introduce post-priority-date evidence showing that Appellees 

engaged in lengthy and potentially undue experimentation to enable the full scope of the claims. Such evidence 
12 AMGEN INC. v. SANOFI

could have been relevant to determining if the claims 

were enabled as of the priority date and should not have 

been excluded simply because it post-dated the claims’ 

priority date. See, e.g., White Consol. Indus., Inc. v. Vega 

Servo-Control, Inc., 713 F.2d 788, 791 (Fed. Cir. 1983) 

(determining, based on post-priority-date expert evidence 

that “11⁄2 to 2 man years of effort” would be needed to 

practice an invention, that patent claims were not enabled). Accordingly, we reverse the district court’s decision 

excluding Appellants’ post-priority-date evidence of 

enablement and remand for a new trial on enablement.

B 

We next consider whether the trial court improperly 

instructed the jury on written description. The district 

court correctly instructed the jury that in order to satisfy 

the written description requirement, a patentee may 

disclose either a representative number of species falling 

within the scope of the genus or disclose structural features common to the members of the genus so that one of 

skill in the art can visualize or recognize the members of 

the genus. Additionally, however, the district court 

further instructed the jury that: 

In the case of a claim to antibodies, the correlation 

between structure and function may also be satisfied by the disclosure of a newly characterized antigen by its structure, formula, chemical name, or

physical properties if you find that the level of 

skill and knowledge in the art of antibodies at the 

time of filing was such that production of antibodies against such an antigen was conventional or 

routine.

J.A. 1580. Appellants argue that this instruction is 

erroneous because disclosing an antigen does not satisfy 

the written description requirement for a claim to an 

antibody. Appellees respond that the instruction was 

proper because it merely restates the law as set forth in
AMGEN INC. v. SANOFI 13

Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956 (Fed. 

Cir. 2002), Noelle v. Lederman, 355 F.3d 1343 (Fed. Cir. 

2004), and Centocor Ortho Biotech, Inc. v. Abbott Labs., 

636 F.3d 1341 (Fed. Cir. 2011). As discussed below, the 

district court’s instruction is not legally sound and is not

based on any binding precedent. Accordingly, we conclude that the instruction was improper.

The district court’s instruction traces its roots back to 

PTO guidelines first discussed by this court in Enzo 

Biochem. That case involved claims directed to nucleic 

acid probes that were defined by their function of selectively hybridizing to the genetic material of certain bacteria. Enzo Biochem, 323 F.3d at 960. We noted in that 

case that not “all functional descriptions of genetic material fail to meet the written description requirement.” Id. 

at 964. Instead, we cited the PTO’s Guidelines on written 

description for the proposition that “functional characteristics when coupled with a known or disclosed correlation 

between function and structure” may satisfy the written 

description requirement. Id. (citing Guidelines for Examination of Patent Applications Under the 35 U.S.C. 112, ¶ 

1, “Written Description” Requirement 66 Fed. Reg. 1099–

01, 1106 (“Guidelines”)).4 We further noted, in dicta, that 

 

4 The Guidelines were first published on Feb. 28, 

2000 as the Revised Interim Written Description Guidelines Training Materials. In March 2008, the training 

materials were revised and republished as Written Description Training Materials, Revision 1, available at 

https://www.uspto.gov/sites/default/files/web/menu/

written.pdf. The PTO now notes that the Training Materials have been “archived” and that “[a] new version will 

be prepared to reflect changes in the law since 2008, 

including any required clarifications due to developments 

in the law relating to 35 U.S.C. 112.” Examination Guidance and Training Materials, United States Patent and 
14 AMGEN INC. v. SANOFI

“the PTO would find compliance with 112, [¶] 1, for a 

claim to an isolated antibody capable of binding to antigen 

X, notwithstanding the functional definition of the antibody, in light of the well-defined structural characteristics 

for the five classes of antibody, the functional characteristics of antibody binding, and the fact that the antibody 

technology is well developed and mature.” Id. (citing 

Synopsis of Application of Written Description Guidelines, 

at 60, available at https://web.archive.org/

web/20041101121800/http://www.uspto.gov/web/menu/wri

tten.pdf).

In Noelle, the patent owner claimed an antibody and 

sought to claim priority to an earlier filed patent. 355 

F.3d at 1349. Noelle argued that “because antibodies are 

defined by their binding affinity to their antigens, he

sufficiently described [the claimed antibody] by stating 

that it binds to [a disclosed antigen].” Id. We rejected this

argument and concluded that the claims were not entitled 

to the earlier priority date because “Noelle failed to disclose the structural elements of [the] antibody or antigen 

in his earlier . . . application.” Id. In reaching this conclusion, we acknowledged that according to Enzo, “as long 

as an applicant has disclosed a ‘fully characterized antigen,’ either by its structure, formula, chemical name, or 

physical properties, or by depositing the protein in a 

public depository, the applicant can then claim an antibody by its binding affinity to that described antigen.” Id. 

But because Noelle did not disclose structure for the 

antibody or the antigen, we did not rely on Enzo to find 

that the patentee had satisfied the written description 

requirement. 

 

Trademark Office, available at https://www.uspto.

gov/patent/laws-and-regulations/examinationpolicy/examination-guidance-and-training-materials. 
AMGEN INC. v. SANOFI 15

Then, in Centocor, we examined Enzo and Noelle as 

well as the PTO Guidelines and held that the antibody 

claims at issue were invalid for lack of written description. 636 F.3d at 1351–53. We noted that under the 

PTO’s Guidelines, “an applicant can claim an antibody to 

novel protein X without describing the antibody when 

(1) the applicant fully discloses the novel protein and 

(2) generating the claimed antibody is so routine that 

possessing the protein places the applicant in possession 

of an antibody.” Id. at 1351–52. The patentee there had 

claimed a “class of antibodies containing a human variable region that have particularly desirable therapeutic 

properties: high affinity, neutralizing activity, and A2 

specificity.” Id. at 1352. The claimed antibodies could 

bind to “the human TNF-α protein.” Id. at 1351. The 

patentee there argued that under Noelle and the PTO 

Guidelines, “fully disclosing the human TNF-α protein 

provides adequate written description for any antibody 

that binds to human TNF-α.” Id. We held, however, that 

even though the patentee had disclosed the human TNF-α

protein, the claims were still invalid. Id. at 1352–53. We 

questioned the propriety of the “newly characterized 

antigen” test and concluded that instead of “analogizing 

the antibody-antigen relationship to a ‘key in a lock,’” it 

was more apt to analogize it to a lock and “a ring with a 

million keys on it.” Id. at 1352. 

Centocor is the only case where we examined the 

“newly characterized antigen” test in some detail. The 

test was not central to the holding in either Enzo or Noelle 

and neither case explored it in much depth. And in 

Noelle, we cautioned that “each case involving the issue of 

written description[] ‘must be decided on its own facts. 

Thus, the precedential value of cases in this area is extremely limited.’” Id. at 1349 (quoting Vas–Cath Inc. v. 

Mahurkar, 935 F.2d 1555, 1562 (Fed. Cir. 1991)). 

The essential problem with the jury instruction given 

in this case is that it effectively permitted the jury to 
16 AMGEN INC. v. SANOFI

dispense with the required finding of a “written description of the invention.” 35 U.S.C. § 112. Our en banc 

decision in Ariad, reflecting earlier decisions such as 

Schriber-Schroth Co. v. Cleveland Trust Co., 305 U.S. 47, 

56–57 (1938), and In re Ruschig, 379 F.2d 990, 991–95 

(CCPA 1967), made clear that, to satisfy the statutory 

requirement of a description of the invention, it is not 

enough for the specification to show how to make and use 

the invention, i.e., to enable it. Ariad, 598 F.3d at 1345–

46, 1347–48. Yet the instruction in this case invites just 

that improper equation. A jury would naturally understand the instruction to permit it to deem any antibody 

within the claim adequately described merely because the 

antibody could easily be “produc[ed]” (and, implicitly,

used as an antibody). J.A. 1580 (requirement “may . . . be 

satisfied” if antigen is newly characterized and “production of antibodies against such an antigen was conventional or routine”). Indeed, the instruction does not even 

require any particular antibody to be easily made; all it 

requires is that “production of antibodies”—some, not 

all—“against [a newly characterized] antigen” be conventional or routine. By permitting a finding of adequate 

written description merely from a finding of ability to 

make and use, the challenged sentence of the jury instruction in this case ran afoul of what is perhaps the core 

ruling of Ariad. 

We cannot say that this particular context, involving 

a “newly characterized antigen” and a functional genus 

claim to corresponding antibodies, is one in which the 

underlying science establishes that a finding of “make and 

use” (routine or conventional production) actually does 

equate to the required description of the claimed products. 

For us to draw such a conclusion, and transform a factual 

issue into a legally required inference, we would have to 

declare a contested scientific proposition to be so settled 

as to be entitled to judicial notice. That we cannot do.
AMGEN INC. v. SANOFI 17

An adequate written description must contain enough 

information about the actual makeup of the claimed 

products—“a precise definition, such as by structure, 

formula, chemical name, physical properties, or other 

properties, of species falling within the genus sufficient to 

distinguish the genus from other materials,” which may 

be present in “functional” terminology “when the art has 

established a correlation between structure and function.” 

Ariad, 598 F.3d at 1350. But both in this case and in our 

previous cases, it has been, at the least, hotly disputed 

that knowledge of the chemical structure of an antigen 

gives the required kind of structure-identifying information about the corresponding antibodies. See, e.g., J.A. 

1241 (549:5–16) (Appellants’ expert Dr. Eck testifying 

that knowing “that an antibody binds to a particular 

amino acid on PCSK9 . . . does not tell you anything at all 

about the structure of the antibody”); J.A. 1314 (836:9–11) 

(Appellees’ expert Dr. Petsko being informed of Dr. Eck’s 

testimony and responding that “[m]y opinion is that [he’s] 

right”); Centocor, 636 F.3d at 1352 (analogizing the antibody-antigen relationship as searching for a key “on a 

ring with a million keys on it”) (internal citations and 

quotation marks omitted). 

A court may take judicial notice of a fact only when it 

is either “generally known” or “accurately and readily 

[discernible] from sources whose accuracy cannot reasonably be questioned.” Fed. R. Evid. 201(b); see B.V.D. 

Licensing Corp. v. Body Action Design, Inc., 846 F.2d 727, 

728 (Fed. Cir. 1988) (“Courts may take judicial notice of 

facts of universal notoriety, which need not be proved, and 

of whatever is generally known within their jurisdictions.” 

(citing Brown v. Piper, 91 U.S. 37 (1875))). Because the 

scientific premise behind the “newly characterized antigen” test stated in the instruction in this case was neither 

“generally known” nor “accurately and readily” ascertainable, we cannot take judicial notice of the premise and 

displace the required fact finding with what amounts to a 
18 AMGEN INC. v. SANOFI

rule of law. We are not required to conclude otherwise, 

and depart from the plain restriction on judicial notice, by 

the statement in Enzo, which was unnecessary to its 

holding, about what PTO Guidelines indicated the PTO 

would find.

Further, the “newly characterized antigen” test flouts 

basic legal principles of the written description requirement. Section 112 requires a “written description of the 

invention.” But this test allows patentees to claim antibodies by describing something that is not the invention, 

i.e., the antigen. The test thus contradicts the statutory 

“quid pro quo” of the patent system where “one describes 

an invention, and, if the law’s other requirements are 

met, one obtains a patent.” Ariad, 598 F.3d at 1345. 

Indeed, we have generally eschewed judicial exceptions to 

the written description requirement based on the subject 

matter of the claims. See Univ. of Rochester v. G.D. Searle 

& Co., 358 F.3d 916, 925 (Fed. Cir. 2004) (noting that “the 

statute applies to all types of inventions”). And Congress 

has not created a special written description requirement 

for antibodies as it has, for example, for plant patents. 

See, e.g., 35 U.S.C. § 162 (exempting plant patents from 

§ 112 “if the description is as complete as is reasonably 

possible”). 

For those reasons, it was improper for the district 

court to instruct the jury as it did in the sentence at issue 

here. On remand, the district court should amend its jury 

instructions accordingly. 

C 

Next, we consider whether the district court improperly denied Appellants’ post-trial motion seeking JMOL of 

no written description and no enablement. Appellants 

argue that the asserted patents fail to provide written 

description support because they merely teach “where an 

antibody binds to an antigen” which “tells one nothing 

about the structure of any other antibody.” Appellants’ 
AMGEN INC. v. SANOFI 19

Br. 53. Appellants also argue that the patents are not 

enabling because one must engage in several steps including a trial-and-error process of generating and screening 

antibodies, performing x-ray crystallography, and still 

potentially failing to “get a sufficient number of antibodies that enable the full scope of the claims.” Id. 

JMOL is proper when “a reasonable jury would not 

have a legally sufficient evidentiary basis to find for the 

party.” Fed. R. Civ. P. 50(a)(1). “A determination that a 

patent is invalid for failure to meet the written description requirement of 35 U.S.C. § 112, ¶ 1 is a question of 

fact, and we review a jury’s determinations of facts relating to compliance with the written description requirement for substantial evidence.” Ariad, 598 F.3d at 1355

(citing PIN/NIP, Inc. v. Platte Chem. Co., 304 F.3d, 1235, 

1243 (Fed. Cir. 2002)). And “[t]o be enabling, the specification of a patent must teach those skilled in the art how 

to make and use the full scope of the claimed invention 

without undue experimentation.” Genentech, 108 F.3d at

1365 (internal quotation marks omitted). But 

“[e]nablement is not precluded by the necessity for some 

experimentation such as routine screening” of antibodies. 

In re Wands, 858 F.2d 731, 736–37 (Fed. Cir. 1988). 

Here, the jury did not hear relevant post-priority-date 

evidence regarding written description and enablement. 

This evidence may show, for example, that practicing the 

invention did not require undue experimentation or that 

the disclosed species are representative of the claimed 

genus. Because we are presented with an incomplete 

record on these issues, the court is unable to determine 

whether the jury would have a “legally sufficient evidentiary basis” to determine if the patents provide sufficient 

written description or if the claims are enabled. Fed. R. 

Civ. P. 50(a)(1). We therefore reject Appellants’ arguments and conclude that Appellants are not entitled to 

JMOL of no written description and no enablement. 
20 AMGEN INC. v. SANOFI

D 

We next address whether the district court improperly 

granted Appellees’ JMOL of non-obviousness. Because 

the district court correctly excluded Appellants’ proffered

references as improper prior art, we conclude that the 

district court’s grant of Appellees’ motion seeking JMOL

of non-obviousness was proper.

During litigation, Appellants sought to invalidate the 

asserted patents by proffering two published PCT applications: Novartis (WO 2008/12563) and Schering (WO 

2009/055783). Neither reference predates the January 9, 

2008 priority date of the asserted patents. But both 

applications claim priority to provisional applications that 

do predate the asserted patents’ priority date.5 In the 

district court, Appellants attempted to rely on these PCT 

applications as pre-AIA § 102(e)(1) art. 35 U.S.C. 

§ 102(e)(1) (providing “an application for patent, published under section 122(b), by another filed in the United 

States before the invention by the applicant for patent”). 

Appellees argued, however, that the references were not 

proper prior art because Appellants had not shown that 

the provisional applications provided written description 

support for the claims of the PCT applications. The 

district court agreed, excluded the two references, and 

granted JMOL of non-obviousness.

Appellants argue that the district court erred by misapplying our decision in Dynamic Drinkware, LLC v. 

National Graphics, Inc., 800 F.3d 1375 (Fed. Cir. 2015). 

According to Appellants, that case only related to whether 

“a patent asserted as prior art under § 102(e)(2) was prior 

art as of the filing date of a parent application” but does 

 

5 It is undisputed that the provisional applications 

are not themselves prior art under § 102(e)(1) because 

they are not applications published under § 122(b).
AMGEN INC. v. SANOFI 21

not relate to whether “published patent applications 

asserted as prior art under § 102(e)(1)” were prior art as 

of the filing date of their provisional applications. Appellants’ Br. 46. Appellants are incorrect. 

In Dynamic Drinkware, we clearly explained that for 

a non-provisional application to claim priority to a provisional application for prior art purposes, “the specification 

of the provisional [application] must contain a written 

description of the invention . . . in such full, clear, concise, 

and exact terms, to enable an ordinarily skilled artisan to 

practice the invention claimed in the non-provisional

application.” 800 F.3d at 1378. Further, we have previously stated that “for the non-provisional utility application to be afforded the priority date of the provisional 

application, . . . the written description of the provisional 

must adequately support the claims of the non-provisional 

application.” New Railhead Mfg., L.L.C. v. Vermeer Mfg. 

Co., 298 F.3d 1290, 1294 (Fed. Cir. 2002). 

Here, Appellants challenged the district court’s application of Dynamic Drinkware, but did not proffer any 

evidence showing that the provisional applications contained representative species or common structural 

elements sufficient to satisfy the written description 

requirement for the monoclonal antibodies claimed in the 

PCT applications. Similarly, Appellants provided no 

evidence that the claims of the PCT applications were 

enabled by the provisional application. Because the 

district court properly excluded Novartis and Schering 

under Dynamic Drinkware, the court’s grant of JMOL of 

non-obviousness was proper. 

E 

Finally, we address the district court’s permanent injunction removing Appellants’ Praluent from the market. 

As noted earlier, we stayed this injunction pending resolution of this appeal. Because we vacate the district 

court’s judgment as to written description and enable-
22 AMGEN INC. v. SANOFI

ment and remand for a new trial, we also vacate the 

permanent injunction.

We write to note, however, that the district court’s 

permanent injunction analysis in this case was improper

for two distinct reasons. First, the district court misapplied eBay, Inc. v. MercExchange, L.L.C., 547 U.S. 388 

(2006). In that case, the Supreme Court explained that: 

[A] plaintiff seeking a permanent injunction must

satisfy a four-factor test before a court may grant 

such relief. A plaintiff must demonstrate: (1) that 

it has suffered an irreparable injury; (2) that remedies available at law, such as monetary damages, 

are inadequate to compensate for that injury; 

(3) that, considering the balance of hardships between the plaintiff and defendant, a remedy in 

equity is warranted; and (4) that the public interest would not be disserved by a permanent injunction.

Id. at 391 (emphases added). Here, the district court 

concluded that issuing a permanent injunction would 

disserve the public interest. Despite that finding, the 

court issued a permanent injunction. J.A. 33–34. That 

was in clear violation of eBay. If a plaintiff fails to show 

“that the public interest would not be disserved by a 

permanent injunction,” then the district court may not 

issue an injunction. eBay, 547 U.S. at 391.

Second, the district court also erred in its analysis of 

the “public interest” factor. In reaching its conclusion

that the injunction would disserve the public, the district 

court weighed “being a patent holder and a verdict winner” on the one hand and “taking an independently developed, helpful drug off the market” on the other. J.A. 33. 

It then “conclude[d] that the public interest of having a 

choice of drugs should prevail.” J.A. 33–34. 
AMGEN INC. v. SANOFI 23

But eliminating a choice of drugs is not, by itself, sufficient to disserve the public interest. Under such an 

approach, courts could never enjoin a drug because doing 

so would always reduce a choice of drugs. That, of course, 

is not the law. See 35 U.S.C. § 271(e)(4)(B) (“[I]njunctive 

relief may be granted against an infringer to prevent the 

commercial manufacture, use, offer to sell, or sale within 

the United States or importation into the United States of 

an approved drug, veterinary biological product, or biological product.”). We previously rejected such reasoning in

WBIP, LLC v. Kohler Co. and explained that: 

The district court’s decision is based on its reasoning that having more manufacturers of a lifesaving good in the market is better for the public 

interest. But this reasoning is true in nearly every situation involving such goods, such that, if it 

alone is sufficient, it would create a categorical 

rule denying permanent injunctions for life-saving 

goods, such as many patented pharmaceutical 

products. As the Supreme Court has warned, categorical rules regarding permanent injunctions 

are disfavored.

829 F.3d 1317, 1343 (Fed. Cir. 2016). Just as a patent 

owner does not automatically receive an injunction merely 

by proving infringement, see eBay, 547 U.S. at 394, an 

accused infringer cannot escape an injunction merely by 

producing infringing drugs. Accordingly, a reduction in 

choice of drugs cannot be the sole reason for a district 

court to deny an injunction. 

III

For the foregoing reasons, we conclude that the district court erred by (i) categorically excluding Appellants’ 

evidence of written description and enablement, and 

(ii) improperly instructing the jury on written description. 

For these reasons we reverse the district court’s decision 

to exclude Appellants’ evidence of written description and 
24 AMGEN INC. v. SANOFI

enablement and remand for a new trial consistent with 

this opinion. We conclude that Appellants are not entitled to JMOL of no written description and no enablement. We also conclude that the district court properly 

granted Appellees’ JMOL of non-obviousness. Finally, we 

vacate the permanent injunction and remand for further 

proceedings consistent with this opinion.

REVERSED IN PART, AFFIRMED IN PART, 

VACATED IN PART, AND REMANDED