In Re: Aflibercept Patent Litigation

IN THE UNITED STATES DISTRICT COURT
FOR THE NORTHERN DISTRICT OF WEST VIRGINIA
IN RE: AFLIBERCEPT PATENT
LITIGATION 	MDL No. 1:24-MD-3103
This Document Relates to:
No. 1:25-cv-74
MEMORANDUM OPINION AND ORDER GRANTING IN PART REGENERON’S MOTION
TO STRIKE CERTAIN AFFIRMATIVE DEFENSES AND DISMISS CERTAIN
COUNTERCLAIMS [ECF NO. 680]
Pending 	before 	the 	Court 	is 	Plaintiff 	Regeneron
Pharmaceuticals, 	Inc.’s 	(“Regeneron”) 	Motion 	to 	Strike 	Certain
Affirmative 	Defenses 	and 	Dismiss 	Certain 	Counterclaims
(“Regeneron’s Motion”) [ECF No. 680]. 	The Court convened for oral
argument 	on 	April 	7, 	2026. 	ECF 	No. 	802. 	The 	motion 	is 	fully
briefed 	and 	ripe 	for 	decision. 	For 	the 	reasons 	set 	forth 	herein,
the motion is GRANTED IN PART and DENIED IN PART.
I. 	PROCEDURAL BACKGROUND
In 	January 	2024, 	Regeneron 	filed 	suit against 	Defendant 	Amgen,
Inc. 	(“Amgen”) 	in 	the 	Central 	District 	of 	California 	alleging
infringement 	of 	32 	patents 	relating 	to 	its 	biologic 	Eylea 	in
response 	to 	Amgen’s 	submission 	of 	an 	abbreviated 	Biologics 	Drug
Application for ABP 938, a proposed biosimilar of Eylea. 	Regeneron
Pharm., Inc. v. Amgen Inc., Case No. 2:24-cv-264 (C.D. Cal.). 	That
case was then consolidated with other Eylea biosimilar cases then-
pending before this Court. In re Aflibercept Pat. Litig., 2024 WL
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1597512, 	at 	*1 	(J.P.M.L. 	Apr. 	11, 	2024). 	As 	part 	of 	those
proceedings, this Court denied Regeneron’s motion for preliminary
injunction against Amgen, ECF No. 343 (“PI Order”), and the Federal
Circuit 	affirmed, 	Regeneron 	Pharmaceuticals, 	Inc. 	v. 	Mylan
Pharmaceuticals 	Inc., 	130 	F.4th 	1372, 	1379–80 	(Fed. 	Cir. 	2025)
(“CAFC Opinion”). 	Both opinions relied on the accused formulation
lacking 	a 	separate 	buffer 	required 	by 	the 	asserted 	claims. 	PI
Order at 24-28; CAFC Opinion at 1383-84.
In June 2025, Regeneron brought the present action asserting
U.S. 	Patent 	No. 	12,331,099 	(the 	“’099 	patent”), 	which 	was 	also
consolidated with the ongoing multidistrict litigation. 	Judicial
Panel on Multidistrict Litigation Conditional Transfer Order (ECF
No. 	577). 	In 	its 	answer 	to 	the 	2025 	complaint, 	Amgen 	alleges
inequitable conduct in the procurement of the ’099 patent. 	Amgen’s
Corrected 	Answer 	at 	¶¶ 	52-98, 	229-278 	(ECF 	No. 	666). 	Amgen 	also
alleges 	antitrust 	violations 	based 	on 	the 	assertion 	of 	the 	’099
patent and twelve other patents previously but no longer asserted
against Amgen (the “2024 Litigation Patents”) (id. at ¶¶ 294-324)
and asserts additional defenses and counterclaims based in laches
(id. at ¶¶ 48-50, 217-228), patent misuse (id. at ¶¶ 99-111, 279-
293), 	and 	unclean 	hands 	(id. 	at 	¶ 	41), 	in 	addition 	to 	others 	not
challenged in Regeneron’s Motion.
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II. 	MOTIONS TO STRIKE AND DISMISS STANDARDS
Federal 	Rule 	of 	Civil 	Procedure 	(“FRCP”) 	12(b)(6) 	allows 	a
plaintiff to move for dismissal of a counterclaim upon the ground
that 	the 	answer 	does 	not 	“state 	a 	claim 	upon 	which 	relief 	can 	be
granted.” 	In ruling on a 12(b)(6) motion to dismiss, a court must
accept 	as 	true 	all 	of 	the 	factual 	allegations 	contained 	in 	the
pleading. 	Anderson v. Sara Lee Corp., 508 F.3d 181, 188 (4th Cir.
2007) 	(quoting 	Erickson 	v. 	Pardus, 	551 	U.S. 	89, 	94 	(2007)).
However, a court is “not bound to accept as true a legal conclusion
couched as a factual allegation.” Papasan v. Allain, 478 U.S. 265,
286 (1986).
FRCP 	12(f) 	allows 	the 	Court 	to 	“strike 	from 	a 	pleading 	an
insufficient 	defense.” 	Any 	defense 	that 	“would 	not, 	under 	the
facts 	alleged, 	constitute 	a 	valid 	defense 	to 	the 	action 	can 	and
should 	be 	deleted.” 	Waste 	Mgmt. 	Holdings, 	Inc. 	v. 	Gilmore, 	252
F.3d 	316, 	347 	(4th 	Cir. 	2001). 	“If 	a 	movant 	can 	show 	that 	a
defense is clearly insufficient, the court should grant the motion
to 	strike.” 	EEOC 	v. 	Route 	22 	Sports 	Bar, 	Inc., 	2021 	WL 	2557087,
at *2 (N.D.W. Va. June 22, 2021).
III. DISCUSSION
A. Inequitable Conduct
Regeneron 	challenges 	Amgen’s 	Thirteenth 	Additional 	Defense
and 	Fourth 	Counterclaim, 	which 	allege 	inequitable 	conduct 	in 	the
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fraudulent 	procurement 	of 	the 	2024 	Litigation 	Patents 	and 	’099
patent. 	Amgen’s Corrected Answer at ¶¶ 52-98, 229-278.
“Inequitable 	conduct 	is 	an 	equitable 	defense 	to 	patent
infringement 	that, 	if 	proved, 	bars 	enforcement 	of 	a 	patent.”
Therasense, 	Inc. 	v. 	Becton, 	Dickinson 	& 	Co., 	649 	F.3d 	1276, 	1285
(Fed. 	Cir. 	2011). 	“To 	prevail 	on 	the 	defense 	of 	inequitable
conduct, 	the 	accused 	infringer 	must 	prove 	that 	the 	applicant
misrepresented 	or 	omitted 	material 	information 	with 	the 	specific
intent to deceive the PTO.” 	Id. at 1287.
In 	response 	to 	several 	noted 	problems 	with 	the 	high 	volume
and 	low 	quality 	of 	inequitable 	conduct 	assertions, 	the 	Federal
Circuit 	raised 	the 	bar 	for 	the 	defense 	in, 	among 	other 	opinions,
Star 	Scientific 	Inc. 	v. 	R.J. 	Reynolds 	Tobacco 	Co., 	537 	F.3d 	1357
(Fed. Cir. 2008); Exergen Corp. v. Wal-Mart Stores, Inc., 575 F.3d
1312 (Fed. Cir. 2009); and Therasense, 649 F.3d 1276. 	As announced
in Therasense, “the materiality required to establish inequitable
conduct 	is 	but-for 	materiality.” 	640 	F.3d 	at 	1291-92. 	In 	other
words, 	the 	party 	alleging 	inequitable 	conduct 	must 	show 	that 	the
patent 	in 	question 	would 	not 	have 	issued 	but 	for 	the 	alleged
conduct.
Though 	the 	question 	of 	“[w]hether 	inequitable 	conduct 	has
been adequately pled is a procedural matter,” “it bears on an issue
that 	‘pertains 	to 	or 	is 	unique 	to 	patent 	law’” 	and 	thus 	Federal
Circuit law applies. 	Central Admixture Pharmacy Services, Inc. v.
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Advanced 	Cardiac 	Solutions, 	P.C., 	482 	F.3d 	1347, 	1356–57 	(Fed.
Cir. 	2007), 	cert. 	denied, 	128 	S. 	Ct. 	648 	(2007) 	(quoting 	Intel
Corp. v. Commonwealth Sci. & Indus. Research Org., 455 F.3d 1364,
1369 (Fed. Cir. 2006)).
As 	a 	form 	of 	fraud 	(formerly 	known 	as 	“fraud 	on 	the 	Patent
Office,” 	see 	6 	R OBERT A. MATTHEWS , JR ., ANNOTATED PATENT DIGEST 	§ 	39:13
(2026)), inequitable conduct pleading must meet the particularity
requirement 	of 	FRCP 	9(b). 	Exergen, 	575 	F.3d 	at 	1326–27. 	That
particularity 	requirement 	applies 	whether 	inequitable 	conduct 	is
raised 	as 	a 	counterclaim 	or 	an 	additional 	defense. 	Id. 	at 	1317,
1325-31 	(applying 	FRCP 	9(b) 	to 	counterclaim 	and 	affirmative
defense 	without 	distinction); 	FRCP 	9(b) 	(“[I]n 	all 	averments 	of
fraud or mistake, the circumstances constituting fraud or mistake
shall 	be 	stated 	with 	particularity.”) 	(emphasis 	added); 	See 	also
Int'l 	Bus. 	Machines 	Corp. 	v. 	Priceline 	Grp. 	Inc., 	No. 	CV 	15-137-
LPS-CJB, 	2017 	WL 	1349175, 	at 	*4 	(D. 	Del. 	Apr. 	10, 	2017); 	Chiron
Corp. v. Abbott Lab'ys, 156 F.R.D. 219, 221 (N.D. Cal. 1994).
Specifically, 	under 	FRCP 	9(b), 	proper 	inequitable 	conduct
pleading “requires identification of the specific who, what, when,
where, 	and 	how 	of 	the 	material 	misrepresentation 	or 	omission
committed before the PTO” and “must include sufficient allegations
of 	underlying 	facts 	from 	which 	a 	court 	may 	reasonably 	infer 	that
a specific individual (1) knew of the withheld material information
or 	of 	the 	falsity 	of 	the 	material 	misrepresentation, 	and 	(2)
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withheld or misrepresented this information with a specific intent
to deceive the PTO.” 	Exergen, 575 F.3d at 1327-29.
While 	Amgen’s 	answer 	“describe[s] 	how 	Regeneron’s
representatives withheld material references from the PTO, only to
disclose them late in the examination process, in a manner designed
to 	obscure 	their 	materiality,” 	“those 	allegations 	go 	to
Regeneron’s intent” and are not themselves alleged as instances of
inequitable 	conduct. 	Amgen’s 	Opposition 	at 	12 	(ECF 	No. 	703).
Rather, 	Amgen 	alleges 	inequitable 	conduct 	in 	two 	allegedly 	false
representations made to the PTO by Regeneron. 	Id.
First, 	Amgen 	alleges 	that 	Regeneron 	submitted 	false
inventorship declarations when obtaining the ’099 patent. 	Amgen’s
Corrected 	Answer 	at 	¶¶ 	56-81. 	Specifically, 	Amgen 	disputes
inventorship 	with 	respect 	to 	the 	lack 	of 	a 	buffer 	in 	the
aflibercept 	formulation 	claimed 	by 	the 	’099 	patent. 	During
prosecution, Regeneron resubmitted inventorship declarations used
in a 	parent application1 that did 	require a buffer, in 	compliance
with § 602.05 of the Manual of Patent Examining Procedure. 	Amgen
alleges that those declarations are false because of the allegedly
new subject matter of the ’099 patent.
In evaluating Amgen’s pleading under FRCP 9(b), this Court is
not 	required 	to 	accept 	unsupported 	conclusions 	or 	those 	based
1 U.S. Patent App. No. 13/914,996; issued as U.S. Patent No. 8,481,046.
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merely 	on 	“information 	and 	belief” 	without 	further 	factual
support. 	Exergen, 575 F.3d at 1330 (affirming denial of leave to
amend 	answer 	to 	add 	inequitable 	conduct 	counterclaim 	against
specific entities where allegation was based only on “information
and 	belief”). 	While 	it 	is 	true 	that 	pleading 	based 	on
“‘information 	and 	belief’ 	is 	permitted 	under 	Rule 	9(b) 	when
essential 	information 	lies 	uniquely 	within 	another 	party’s
control,” such pleading must still “set[] forth the specific facts
upon which the belief is reasonably based.” 	Id.
Such 	specific 	facts 	are 	important 	“lest 	inequitable 	conduct
devolve 	into 	‘a 	magic 	incantation 	to 	be 	asserted 	against 	every
patentee.’” 	Exergen, 	575 	F.3d 	at 	1331 	(quoting 	FMC 	Corp. 	v.
Manitowoc 	Co., 	Inc., 	835 	F.2d 	1411, 	1415 	(Fed. 	Cir. 	1987)).
Indeed, Federal Circuit case law requires “specific and demanding
showings 	of 	evidence 	before 	a 	party 	may 	assert 	the 	defense 	of
inequitable conduct.” 	Pressure Products Medical Supplies, Inc. v.
Greatbatch 	Ltd., 	599 	F.3d 	1308, 	1320 	(Fed. 	Cir. 	2010) 	(affirming
denial of leave to amend answer to add inequitable conduct defense
based on undue delay and noting likely insufficiency of pleading).
Amgen pleads little in the way of specific facts that distinguish
its pleading from that which could be made in every case of patent
infringement.
The 	only 	specific 	facts 	Amgen 	pleads 	to 	support 	its
inventorship 	conclusion 	are 	its 	own 	buffer-free 	aflibercept
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product, 	ABP 	938, 	and 	patent 	filings; 	the 	PI 	Order 	and 	CAFC
Opinion; 	and 	testimony 	from 	named 	inventors 	of 	the 	’099 	patent
regarding 	U.S. 	Patent 	No. 	11,084,865 	(the 	“’865 	patent”) 	made
during 	prosecution 	and 	subsequent 	litigation 	to 	the 	effect 	that
the ’865 patent’s aflibercept formulation requires a buffer. 	While
these facts might support an inference that Regeneron was motivated
to 	seek 	patent 	claims 	not 	including 	a 	buffer, 	it 	is 	unclear 	how
these 	facts 	support 	the 	conclusion 	that 	the 	’099 	patent’s
inventorship declaration was false. Indeed, Amgen’s answer merely
recites 	these 	facts 	before 	drawing 	its 	conclusion 	(see 	Amgen’s
Corrected 	Answer 	at 	¶ 	79) 	and 	offers 	no 	clarification 	in 	its
Opposition (Amgen’s Opposition at 12-15) (ECF No. 703).
Thus, 	because 	Amgen’s 	“allegations 	of 	underlying 	facts” 	do
not 	allow 	this 	Court 	to 	reasonably 	infer 	that 	inventorship 	was
indeed 	false, 	those 	allegations 	do 	not 	allow 	this 	Court 	to
“reasonably infer that a specific individual (1) knew . . . of the
falsity 	of 	the 	material 	misrepresentation, 	and 	(2) 	. 	. 	.
misrepresented this information with a specific intent to deceive
the PTO.” 	Exergen, 575 F.3d at 1328-29.
Amgen’s 	other 	allegation 	of 	inequitable 	conduct 	is
Regeneron’s 	October 	23, 	2024, 	submission 	of 	a 	preliminary
amendment and its statement that “[n]o new matter enters by way of
the 	present 	amendments.” 	Amgen’s 	Corrected 	Answer 	at 	¶¶ 	62, 	81,
96. 	As 	with 	its 	inventorship 	theory, 	Amgen 	does 	not 	provide
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factual support that elevates its pleading above what any accused
infringer could plead where a patentee has amended its claims.
As two other district courts have noted (both before and after
the Federal Circuit raised the bar for inequitable conduct in Star
Scientific, 	Exergen, 	and 	Therasense), 	an 	applicant’s 	statement
that 	an 	amendment 	contains 	no 	new 	matter 	is 	not 	itself 	material.
Wilson Tool Int'l Inc. v. Mate Precision Tooling Inc., No. CV 17-
4608, 	2018 	WL 	6706326, 	at 	*11 	(D. 	Minn. 	Apr. 	19, 	2018) 	(granting
motion 	to 	dismiss 	inequitable 	conduct 	counterclaim 	and 	citing
Neutrino Dev't Corp. v. Sonosite, Inc., 512 F. Supp. 2d 1004, 1009
(S.D. 	Tex. 	2007) 	aff'd, 	269 	F. 	App'x 	976 	(Fed. 	Cir. 	2008)).
Without 	further 	factual 	support, 	“[t]he 	statement 	that 	there 	is
‘no new matter’ contained in a patent amendment is no more material
than 	a 	statement 	by 	a 	patentee 	that 	a 	patent 	is 	‘valid.’”
Neutrino, 	512 	F. 	Supp. 	2d 	at 	1009 	n.14. 	Such 	statements 	“would
not 	bear 	upon 	any 	reasonable 	patent 	examiner’s 	evaluation 	of 	a
patent 	application” 	and 	“are 	legal 	conclusions 	outside 	of 	the
purview of a patentee.” 	Id.
Indeed, the examiner “had before him all material relevant to
making 	an 	independent 	determination 	of 	new 	matter 	as 	he 	was
required 	to 	do” 	and 	the 	applicant’s 	statement 	“was 	cumulative 	to
other correct material already of record pertaining to the question
of new matter and the statement was not inconsistent with any other
position 	taken 	by 	[applicant] 	during 	the 	prosecution.” 	Wilson
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Tool, 	2018 	WL 	6706326, 	at 	*11 	(quoting 	Neutrino, 	512 	F. 	Supp. 	2d
at 1009-10).
Thus, 	because 	Amgen 	presents 	no 	further 	factual 	support 	for
the materiality of the allegedly false statement, this Court cannot
“reasonably infer that a specific individual (1) knew . . . of the
falsity of the material misrepresentation.” 	Exergen, 575 F.3d at
1328-29 (emphasis added).
Regeneron’s 	motion 	is 	therefore 	GRANTED 	with 	respect 	to
Amgen’s Thirteenth Additional Defense and Fourth Counterclaim.
B. Antitrust
Regeneron 	next 	challenges 	Amgen’s 	Sixth 	through 	Eighth
Counterclaims, 	which 	allege 	antitrust 	violations 	based 	on 	the
alleged fraudulent procurement of the 2024 Litigation Patents and
’099 	patent, 	as 	well 	as 	violation 	of 	California’s 	Unfair
Competition Law (“UCL”). 	Amgen’s Corrected Answer at ¶¶ 294-324.
So-called 	“Walker 	Process 	fraud” 	is 	an 	antitrust 	violation
based 	in 	the 	assertion 	of 	fraudulently 	obtained 	patents. 	See
Walker 	Process 	Equip., 	Inc. 	v. 	Food 	Machinery 	& 	Chem. 	Corp., 	382
U.S. 172, 174 (1965). 	Because of their basis in fraud, such claims
are 	subject 	to 	the 	heightened 	pleading 	standards 	of 	FRCP 	9(b).
MedImmune, 	Inc. 	v. 	Genentech, 	Inc., 	427 	F.3d 	958, 	967 	(Fed. 	Cir.
2005).
As 	one 	Federal 	Circuit 	opinion 	has 	noted, 	it 	is 	an 	open
question 	whether 	Walker 	Process 	fraud 	requires 	a 	greater 	showing
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than 	inequitable 	conduct. 	See 	TransWeb, 	LLC 	v. 	3M 	Innovative
Props. 	Co., 	812 	F.3d 	1295, 	1307 	(Fed. 	Cir. 	2016). 	However, 	the
standard 	for 	the 	materiality 	of 	a 	misrepresentation 	underlying 	a
Walker Process claim is that “the patent would not have issued but
for 	the 	patent 	examiner's 	justifiable 	reliance 	on 	the 	patentee's
misrepresentation or omission.” 	Dippin’ Dots, Inc. v. Mosey, 476
F.3d 1337, 1347 (Fed. Cir. 2007).
Amgen’s allegation relating to the ’099 patent fails to state
sufficient facts for this Court to reasonably infer materiality in
the 	alleged 	misrepresentations 	for 	the 	reasons 	discussed 	above
regarding 	Amgen’s 	inequitable 	conduct 	allegations. 	However,
Regeneron’s 	arguments 	regarding 	Amgen’s 	allegations 	based 	in 	the
2024 	Litigation 	Patents 	can 	result 	only 	in 	a 	dismissal 	without
prejudice.
First, 	Regeneron 	argues 	that 	Amgen 	is 	precluded 	from
asserting its antitrust counterclaims under FRCP 13(a) because it
did not assert them in its answer to the suit brought in 2024 (case
number 1:24-cv-39). 	Regeneron’s Motion at 18-20.
Amgen 	does 	not 	appear 	to 	contest 	that 	its 	counterclaim 	was
compulsory under FRCP 13(a) other than to argue that Mercoid Corp.
v. 	Mid-Continent 	Inv. 	Co., 	320 	U.S. 	661, 	671 	(1944) 	creates 	an
exception 	for 	antitrust 	counterclaims 	to 	patent 	infringement
claims. 	Amgen’s 	Opposition 	at 	21-22. 	Regeneron 	responds 	that
Mercoid 	should 	be 	limited 	to 	its 	facts, 	which 	are 	importantly
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distinct 	here. 	This 	Court 	agrees 	with 	Regeneron 	and 	finds 	that
Amgen’s counterclaim was compulsory in case number 1:24-cv-39.
The 	parties’ 	positions 	on 	this 	issue 	have 	been 	discussed
significantly 	in 	judicial 	opinion 	and 	scholarly 	comment.
See, e.g., 	6 	R OBERT 	A. 	MATTHEWS , 	JR ., 	ANNOTATED 	PATENT 	DIGEST 	§ 	39:29
(2026); 6 C HARLES WRIGHT & MILLER ’S F EDERAL PRACTICE & PROCEDURE § 1412 (3d
ed.) 	As 	Regeneron 	notes, 	the 	Fourth 	Circuit 	has 	expressed 	that
Mercoid “has been read narrowly . . . and its continuing validity
is 	open 	to 	serious 	question.” 	Burlington 	Indus. 	v. 	Milliken 	&
Co., 690 F.2d 380, 389 (4th Cir. 1982), cert. denied, 461 U.S. 914
(1983); see also United States v. Eastport Steamship Corporation,
255 F.2d 795 (2d Cir. 1958) (“[I]n view of the criticism which the
decision has received and the failure of the Court to discuss the
principles 	upon 	which 	the 	decision 	rests, 	we 	think 	that 	Mercoid
cannot 	be 	taken 	as 	precedent 	for 	other 	than 	its 	own 	limited
facts.”). 	Importantly, 	Walker 	Process 	claims 	like 	Amgen’s 	would
not be recognized by the Supreme Court for over twenty years after
Mercoid was decided. 	See Walker Process Equip., Inc. v. Food Mach.
& Chemical Corp., 382 U.S. 172, 177–78 (1965); Rohm & Haas Co. v.
Brotech Corp., 770 F. Supp. 928, 932 (D. Del. 1991). 	Accordingly,
this Court will also read Mercoid narrowly.
Many 	important 	distinctions 	exist 	between 	Mercoid 	and 	the
present 	case, 	all 	of 	which 	have 	been 	relied 	on 	to 	persuasively
distinguish Mercoid by other courts.
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First, 	the 	antitrust 	claims 	at 	issue 	in 	Mercoid 	were 	based
only 	on 	the 	misuse 	of 	a 	valid 	and 	otherwise 	enforceable 	patent,
rather than the fraudulent procurement of an invalid patent, which
is 	particularly 	important 	given 	the 	Mercoid 	Court’s 	reliance 	on
the rationale of preventing schemes to expand a valid patent beyond
its legitimate scope. 	See Mercoid, 320 U.S. at 670; Critical-Vac
Filtration Corp. v. Minuteman Intern., Inc., 233 F.3d 697, 702 n.
6 	(2d 	Cir. 	2000) 	(distinguishing 	Mercoid 	on 	this 	ground), 	cert.
denied, 532 U.S. 1019 (2001).
Another important distinction is that the parties to the two
actions 	here 	are 	identical, 	whereas 	the 	subsequent 	defendant 	in
Mercoid 	had 	merely 	paid 	for 	the 	defense 	of 	a 	different 	party 	in
the prior infringement action. 	See Mercoid, 320 U.S. at 669; Lewis
Mfg. Co. v. Chisholm-Ryder Co., 82 F.R.D. 745, 750 (W.D. Pa. 1979)
(distinguishing 	Mercoid 	on 	this 	ground and 	citing 	3 M OORE 'S FEDERAL
PRACTICE P 13.13 n.22 at pp. 13-306-07 (2d ed. 1978)).
Finally, 	in 	Mercoid, 	the 	prior 	infringement 	action 	had
resulted 	in 	a 	final 	judgement 	before 	the 	subsequent 	action 	had
commenced. 	Mercoid, 	320 	U.S. 	at 	669-70; 	Ragner 	Tech. 	Corp. 	v.
Berardi, No. CV1157752NLHAMD, 2018 WL 6804486, at *5 (D.N.J. Dec.
27, 2018) (distinguishing Mercoid on these grounds); see also Rohm
& 	Haas 	Co. 	v. 	Brotech 	Corp., 	770 	F. 	Supp. 	928, 	931-32 	(D. 	Del.
1991).
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However, while this Court finds Amgen’s counterclaim to have
been 	compulsory 	in 	the 	2024 	action, 	the 	lack 	of 	a 	final 	judgment
in that action results in a further complication. 	As noted by the
District 	of 	New 	Jersey 	in 	Ragner, 	a 	prior 	action 	that 	has 	yet 	to
be 	fully 	resolved 	has 	no 	preclusive 	effect. 	2018 	WL 	6804486, 	at
*6; 	Fullerton 	Aircraft 	Sales 	and 	Rentals, 	Inc. 	v. 	Beech 	Aircraft
Corp., 842 F.2d 717, 722 (4th Cir. 1988). 	Instead, “once a court
becomes 	aware 	that 	an 	action 	on 	its 	docket 	involves 	a 	claim 	that
should 	be 	a 	compulsory 	counterclaim 	in 	another 	pending 	federal
suit, 	it 	will 	stay 	its 	own 	proceedings 	or 	will 	dismiss 	the 	claim
with 	leave 	to 	plead 	it 	in 	the 	prior 	action.” 	6 	CHARLES WRIGHT 	&
MILLER ’S FEDERAL P RACTICE & PROCEDURE § 1418 (3d ed.) (collecting cases);
see also Ragner¸ 2018 WL 6804486, at *6-8.
Given that the same court is presiding over both actions here,
the appropriate route is to dismiss Amgen’s counterclaim based on
the 2024 Litigation Patents without prejudice. 	Because the parties
have not briefed the issue of whether Amgen should be granted leave
to amend its Answer to include the antitrust counterclaim regarding
the 	2024 	Litigation 	Patents, 	the 	Court 	will 	not 	here 	decide 	that
issue.
Regeneron’s other argument regarding Amgen’s counterclaim is
not 	sufficient 	to 	justify 	dismissal 	with 	prejudice. 	Regeneron
argues, without direct precedent, that Amgen cannot claim its legal
fees 	in 	case 	number 	1:24-cv-39 	as 	injury 	for 	Regeneron’s 	alleged
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antitrust 	violations 	because 	Amgen 	did 	not 	exclude 	the 	2024
Litigation 	Patents 	from 	its 	“good 	faith 	negotiations 	to 	agree 	on
which, if any, patents” would be litigated in that case as required
by 42 U.S.C. § 262(l)(4)(A). 	Regeneron’s Motion at 20. 	In other
words, Regeneron argues that Amgen is responsible for the assertion
of 	the 	2024 	Litigation 	Patents 	and 	therefore 	cannot 	claim 	the
resulting 	legal 	fees 	as 	injury. 	This 	Court 	is 	not 	persuaded.
Regeneron 	threatened 	to 	assert, 	and 	ultimately 	did 	assert, 	the
patents 	in 	question, 	and 	Amgen 	could 	not 	have 	actually 	defeated
either 	by 	simply 	seeking 	to 	remove 	them 	from 	a 	first 	wave 	of
litigation.
Finally, Regeneron challenges Amgen’s Eighth Counterclaim by
arguing that Amgen’s UCL counterclaim should fall with its Sherman
Act counterclaims. 	Regeneron’s Motion at 22. 	In response, Amgen
relies on the proposition, originating in Cel-Tech Commc’ns, Inc.
v. L.A. Cellular Tel. Co., 20 Cal. 4th 163, 180 (1999), that “[a]
business 	practice 	may 	be 	unfair, 	and 	therefore 	illegal 	under 	the
UCL, 	even 	if 	not 	specifically 	proscribed 	by 	some 	other 	law.”
Amgen’s Opposition at 24.
However, “[f]ollowing Cel-Tech, courts have found that a UCL
claim 	based 	on 	the 	‘unfair’ 	prong 	cannot 	survive 	when 	it 	is
premised 	on 	the 	same 	actions 	as 	an 	alleged 	statutory 	antitrust
claim.” 	Distance 	Learning 	Co. 	v. 	Maynard, 	No. 	19-CV-03801-KAW,
2020 WL 2995529, at *10 (N.D. Cal. June 4, 2020). 	Indeed, “where
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the same conduct alleged to be unfair under the UCL is also alleged
to 	be 	a 	violation 	of 	another 	law, 	the 	UCL 	claim 	rises 	or 	falls
with 	the 	other 	claims.” 	Id. 	quoting 	GreenCycle 	Paint, 	Inc. 	v.
PaintCare, 	Inc., 	Case 	No. 	15-cv-4059-MEJ, 	2016 	U.S. 	Dist. 	LEXIS
47960, at *31, 2016 WL 1402845 (N.D. Cal. Apr. 8, 2016).
Amgen’s 	UCL 	counterclaim 	contains 	no 	allegation 	of 	conduct
distinct 	from 	that 	alleged 	in 	its 	Sherman 	Act 	counterclaims 	and
therefore 	falls 	with 	those 	counterclaims. 	Regeneron’s 	motion 	is
therefore 	GRANTED 	with 	respect 	to 	Amgen’s 	Eighth 	Counterclaim,
though 	its 	UCL 	claim 	based 	on 	its 	allegations 	of 	fraudulent
procurement 	of 	the 	2024 	Litigation 	Patents 	is 	only 	dismissed
without prejudice.
C. Laches
Regeneron 	also 	seeks 	to 	strike 	Amgen’s 	Eleventh 	Additional
Defense 	and 	dismiss 	Amgen’s 	Third 	Counterclaim, 	which 	allege
unenforceability 	of 	the 	’099 	patent 	due 	to 	prosecution 	laches.
Regeneron’s 	Motion 	at 	24-25. 	Specifically, 	Amgen 	alleges 	that
Regeneron 	unreasonably 	delayed 	in 	pursuing 	the 	’099 	patent 	for
over 	eighteen 	years 	after 	its 	parent 	provisional 	was 	filed,
prejudicing 	Amgen 	in 	light 	of 	Amgen’s 	investment 	in 	developing 	a
buffer-free aflibercept formulation. 	Amgen’s Corrected Answer at
¶¶ 48-50.
Prosecution 	laches 	is 	an 	equitable 	defense 	that 	“may 	render
a 	patent 	unenforceable 	when 	it 	has 	issued 	only 	after 	an
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unreasonable 	and 	unexplained 	delay 	in 	prosecution.” 	Symbol
Techs., 	Inc. 	v. 	Lemelson 	Med., 	Educ. 	& 	Research 	Found., 	422 	F.3d
1378, 	1384-85 	(Fed. 	Cir. 	2005), 	amended 	on 	reh'g 	in 	part 	by, 	429
F.3d 	1051 	(Fed. 	Cir. 	2005). 	The 	parties 	agree 	that 	prosecution
laches 	is 	applicable 	“only 	in 	egregious 	cases 	of 	misuse 	of 	the
statutory patent system.” 	Regeneron’s Motion at 24 (quoting Symbol
Techs., 	Inc. 	v. 	Lemelson 	Med., 	Educ. 	& 	Research 	Found., 	422 	F.3d
1378, 1385 (Fed. Cir. 2005)); Amgen’s Opposition at 25.
Regeneron 	makes 	a 	single 	argument 	that 	Amgen’s 	allegations
fail 	to 	constitute 	such 	an 	egregious 	case: 	that 	“[p]rosecution
laches arose when a patent’s term was defined as 17 years from the
date of the issuance, which incentivized certain patentees to delay
prosecuting 	their 	patents,” 	and 	“because 	the 	timing 	of 	the 	‘099
patent’s issuance is irrelevant to the expiry of its term, laches
is 	inapplicable.” 	Regeneron’s 	Motion 	at 	24-25 	(internal
quotations and citations omitted).
Regeneron’s only authority for its position that prosecution
laches 	does 	not 	apply 	to 	patents 	applied 	for 	after 	the 	General
Agreement on Tariffs and Trade (“GATT”) changed the expiration of
U.S. 	patents 	to 	twenty 	years 	after 	their 	application 	date 	is
Chrimar 	Sys. 	v. 	Alcatel-Lucent 	Ent., 	2017 	WL 	345991, 	at 	*4 	(E.D.
Tex. 	Jan. 	24, 	2017), 	which 	held 	that 	the 	change 	in 	expiry
“alleviate[d] 	the 	need 	for 	the 	equitable 	remedy.” 	However, 	that
same paragraph in Chrimar goes on to conclude: “Here, there is no
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evidence 	cited 	by 	ALE 	that 	there 	was 	any 	unreasonable 	or
unexplained 	delays 	in 	prosecution 	or 	any 	conduct 	by 	Chrimar 	to
support 	such 	a 	delay.” 	2017 	WL 	345991, 	at 	*4. 	This 	further
reasoning, 	in 	combination 	with 	that 	court’s 	usage 	of 	the 	term
“alleviate,” 	indicates 	that 	there 	was 	no 	announcement 	of 	a 	rule
that 	the 	date 	of 	application 	alone 	is 	dispositive 	of 	prosecution
laches, and Regeneron provides no such pronouncement from any other
court.
Moreover, 	several 	courts 	have 	held 	just 	the 	opposite. 	See
GlaxoSmithKline 	Biologicals 	SA 	v. 	Pfizer 	Inc., 	No. 	24-512-GBW,
2026 WL 1732953, *3-4 (D. Del. Jun. 16. 2026) (“[T]he Court rejects
GSK’s contention [that prosecution laches does not extend to post-
GATT 	patents.]”); 	Mojo 	Mobility, 	Inc. 	v. 	Samsung 	Elecs. 	Co., 	No.
22-398, 	2024 	WL 	3354705, 	at 	*1 	(E.D. 	Tex. 	June 	11, 	2024), 	report
and recommendation adopted, No. 22-398, 2024 WL 3350884 (E.D. Tex.
July 9, 2024); Boston Scientific Corp. v. Cook Med. LLC, No. 1:17-
cv-03448-JRS-MJD, 	2023 	WL 	3691113, 	*4 	(S.D. Ind. 	May 	27, 	2023);
Sonos, Inc. v. Google LLC, No. C 20-06754 WHA, 2023 WL 6542320, at
*19 (N.D. Cal. Oct. 6, 2023) (finding prosecution laches for post-
GATT patent and rejecting argument based on expiry change alone),
aff'd in part, rev'd in part, No. 2024-1097, 2025 WL 2473258 (Fed.
Cir. 	Aug. 	28, 	2025) 	(reversing 	finding 	of 	prosecution 	laches 	on
issue 	of 	prejudice 	and 	not 	relying 	on 	post-GATT 	expiry 	of 	patent
at issue).
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Regeneron 	can 	at 	most 	argue 	that 	such 	applications 	of
prosecution 	laches 	fall 	outside 	of 	the 	original 	purpose 	of 	the
prosecution 	laches 	doctrine.2 	However, 	this 	alone 	cannot 	compel
the Court to dismiss Amgen’s allegations at this stage.
Regeneron’s 	motion 	is 	therefore 	DENIED 	with 	respect 	to
Amgen’s Eleventh Additional Defense and Third Counterclaim.
D. Patent Misuse
Regeneron next seeks to strike Amgen’s Fourteenth Additional
Defense 	and 	dismiss 	Amgen’s 	Fifth 	Counterclaim, 	both 	of 	which
allege 	misuse 	of 	the 	’099 	patent. 	Regeneron’s 	Motion 	at 	22-24.
Specifically, Amgen alleges that Regeneron impermissibly broadened
the scope of the ’099 patent when it was amended to not require a
buffer and enforced the patent despite knowing that it was invalid
and 	unenforceable. 	Amgen’s 	Corrected 	Answer 	at 	¶¶ 	99-111, 	279-
293.
“The 	defense 	of 	patent 	misuse 	arises 	from 	the 	equitable
doctrine 	of 	unclean 	hands, 	and 	relates 	generally 	to 	the 	use 	of
patent 	rights 	to 	obtain 	or 	to 	coerce 	an 	unfair 	commercial
advantage.” 	C.R. Bard, Inc. v. M3 Sys., Inc., 157 F.3d 1340, 1372
(Fed. Cir. 1998). 	“Patent misuse relates primarily to a patentee's
2 However, this argument has been rejected by at least three district courts.
See Sonos, 2023 WL 6542320, at *19 (rejecting such an interpretation of
Regeneron’s primary source for this historical argument, Hyatt v. Hirshfeld,
998 F.3d 1347 (Fed. Cir. 2021), and finding post-GATT patents unenforceable
due to prosecution laches); GlaxoSmithKline¸ 2026 WL 1732953, at *3-4
(quoting Mojo Mobility, 2024 WL 3354705, at *1).
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actions 	that 	affect 	competition 	in 	unpatented 	goods 	or 	that
otherwise extend the economic effect beyond the scope of the patent
grant.” 	Id. 	“The key inquiry is whether, by imposing conditions
that 	derive 	their 	force 	from 	the 	patent, 	the 	patentee 	has
impermissibly 	broadened 	the 	scope 	of 	the 	patent 	grant 	with
anticompetitive effect.” 	Id.
Amgen 	alleges 	patent 	misuse 	in 	two 	instances 	of 	Regeneron’s
conduct: its amendment of the claims of the ’099 patent to include
claims 	not 	requiring 	a 	buffer, 	and 	its 	enforcement 	of 	the 	’099
patent. 	Amgen 	alleges 	that 	the 	former 	was 	an 	impermissible
broadening 	of 	the 	scope 	of 	the 	’099 	patent’s 	grant 	and 	that 	the
latter was a bad-faith assertion of a patent fraudulently obtained
and 	which 	Regeneron 	knew 	was 	invalid, 	unenforceable, 	and 	not
infringed.
Amgen’s 	allegations 	regarding 	Regeneron’s 	amendment 	to 	the
’099 	patent’s 	claims 	misstate 	the 	concept 	of 	impermissible
broadening. 	Impermissible 	broadening 	of 	a 	patent 	grant 	cannot
occur 	before 	that 	patent 	is 	granted, 	and 	Amgen 	provides 	no 	such
case 	of 	a 	court 	finding 	patent 	misuse 	for 	amending 	a 	patent’s
claim.
Amgen’s 	allegation 	that 	the 	’099 	patent 	was 	fraudulently
obtained 	fails 	to 	satisfy 	FRCP 	9(b)’s 	factual 	basis 	requirement,
as 	discussed 	above. 	Thus, 	such 	pleading 	cannot 	support 	a 	patent
misuse claim.
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Amgen’s allegations of bad-faith litigation, however, present
a more difficult question to this Court. 	As other district courts
have noted, courts disagree as to whether bad faith alone, without
fraud, 	can 	constitute 	patent 	misuse. 	See 	Bridgestone 	Americas
Tire Operations, LLC v. Speedways Tyres Ltd., No. 4:22-CV-0145-P,
2023 	WL 	2574576, 	at 	*3 	(N.D. 	Tex. 	Mar. 	20, 	2023) 	(collecting
cases); 	see 	also 	Qfix 	Sys., 	LLC 	& 	Anholt 	Techs., 	Inc. 	v. 	Klarity
Med. 	Prods., 	LLC, 	No. 	CV 	23-077 	(CJB), 	2024 	WL 	5692211 	(D. 	Del.
Sept. 25, 2024).
As 	noted 	by 	the 	District 	of 	Delaware 	in 	Qfix, 	the 	root 	of
this disagreement appears to be a contradiction between two Federal
Circuit opinions. 	2024 WL 5692211. 	In Glaverbel Societe Anonyme
v. Northlake Mktg. & Supply, Inc., 45 F.3d 1550 (Fed. Cir. 1995),
the 	Federal 	Circuit 	upheld 	a 	district 	court 	finding 	of 	no 	patent
misuse 	where 	there 	was 	not 	“bad 	faith 	and 	improper 	purpose 	in
bringing the suit,” making no mention of a fraud requirement. 	45
F.3d 	at 	1558-59. 	In 	stating 	a 	requirement 	of 	bad 	faith 	and
improper 	purpose, 	the 	Federal 	Circuit 	relied 	only 	on 	cases 	that
did 	not 	discuss 	patent 	misuse. 	Id. 	at 	1558 	(citing 	American
Tobacco 	Co. 	v. 	United 	States, 	328 	U.S. 	781, 	809 	(1946) 	and 	Grip–
Pak, 	Inc. 	v. 	Illinois 	Tool 	Works, 	Inc., 	694 	F.2d 	466, 	472 	(7th
Cir.1982), cert. denied, 461 U.S. 958 (1983)).
Almost 	four 	years 	later, 	and 	without 	discussing 	Glaverbel,
the 	Federal 	Circuit 	spoke 	more 	clearly 	and 	specifically 	on 	this
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issue 	in 	C.R. 	Bard, 	Inc. 	v. 	M3 	Sys., 	Inc., 	157 	F.3d 	1340 	(Fed.
Cir. 1998). 	In that opinion, the Federal Circuit reversed a jury
finding 	of 	patent 	misuse 	because 	the 	jury 	instruction 	“was
focus[ed] 	primarily 	on 	the 	charge 	that 	Bard 	was 	attempting 	to
enforce 	the 	patents 	against 	goods 	known 	not 	to 	be 	infringing.”
Id. at 1372-73. 	The Federal Circuit also specifically noted that
“[i]t is not patent misuse to bring suit to enforce patent rights
not fraudulently obtained.” 	Id. at 1373.
In 	support 	of 	this 	conclusion, 	the 	opinion 	warns 	that 	“the
body of misuse law and precedent need not be enlarged into an open-
ended 	pitfall 	for 	patent-supported 	commerce.” 	Id. 	The 	opinion
also 	notes 	that 	the 	“’wrongful’ 	enforcement 	of 	patents[] 	is
actively 	protected 	under 	[Eastern 	R.R. 	Presidents 	Conf. 	v. 	Noerr
Motor 	Freight, 	Inc., 	365 	U.S. 	127 	(1961) 	and 	California 	Motor
Transp. Co. v. Trucking Unltd., 404 U.S. 508 (1972)]”. 	Id.
While 	Noerr-Pennington 	immunity 	does 	have 	a 	sham 	litigation
exception, 	patent 	misuse 	is 	a 	separate 	doctrine, 	and 	a 	different
result obtains when patent misuse is found than when an antitrust
violation 	is 	found 	under 	a 	sham 	litigation 	theory, 	namely, 	the
patent 	that 	has 	been 	misused 	is 	found 	unenforceable. 	As 	the
Northern 	District 	of 	Texas 	noted 	in 	Bridgestone, 	such 	a 	result
would 	seem 	contrary 	to 	the 	text 	of 	35 	U.S.C. 	§ 	271(d)(3), 	which
provides that “[n]o patent owner otherwise entitled to relief for
infringement 	or 	contributory 	infringement 	of 	a 	patent 	shall 	be
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denied 	relief 	or 	deemed 	guilty 	of 	misuse” 	when 	it 	“[seeks] 	to
enforce 	[its] 	patent 	rights 	against 	infringement 	or 	contributory
infringement.” 	2023 WL 2574576, at *4 (quoting § 271(d)(3)). 	The
statute 	“provides 	no 	exception 	for 	suits 	brought 	in 	bad 	faith.”
Id.
For 	these 	reasons, 	and 	because 	C.R. 	Bard 	is 	more 	applicable
than Glaverbel, this Court is not persuaded that Amgen can sustain
a 	patent 	misuse 	defense 	or 	counterclaim 	without 	fraudulent
procurement. 	Because 	Amgen’s 	fraudulent 	procurement 	and
impermissible 	broadening 	theories 	are 	not 	sufficiently 	pleaded,
Regeneron’s 	motion 	is 	GRANTED 	with 	respect 	to 	Amgen’s 	Fourteenth
Additional Defense and Fifth counterclaim.
E. Unclean Hands
Finally, Regeneron seeks to strike Amgen’s Fourth Additional
Defense, 	which 	states 	in 	its 	entirety 	that 	“Regeneron’s 	claim 	of
patent infringement is barred in whole or in part by the equitable
doctrines 	of 	waiver, 	estoppel, 	and/or 	unclean 	hands.” 	Amgen’s
Corrected Answer at ¶ 41.
Such 	pleading 	“is 	‘threadbare’ 	and 	provides 	insufficient
notice 	of 	the 	nature 	of 	the 	defense.” 	Tippman 	Eng'g, 	LLC 	v.
Innovative 	Refrigeration 	Sys., 	Inc., 	No. 	5:19-CV-00087, 	2020 	WL
1644985, 	at 	*3 	(W.D. 	Va. 	Apr. 	2, 	2020) 	(striking 	affirmative
defense 	that 	stated 	only 	“[t]he 	claims 	in 	the 	First 	Amended
Complaint 	are 	barred 	by 	the 	Plaintiff's 	unclean 	hands”) 	(quoting
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Flame 	S.A. 	v. 	Indus. 	Carriers, 	Inc., 	No. 	2:13-cv-658, 	2014 	WL
2871432, 	at 	*3 	(E.D. 	Va. 	June 	24, 	2014) 	(striking 	defendant's
defense that “Plaintiff Flame is barred from any equitable remedies
due to its unclean hands”)).
Regeneron’s 	motion 	is 	therefore 	GRANTED 	with 	respect 	to
Amgen’s Fourth Additional Defense.
IV. 	CONCLUSION
For the foregoing reasons, the Court ORDERS as follows:
• 	Regeneron’s Motion is GRANTED IN PART and DENIED IN PART [ECF
No. 680];
• 	Amgen’s 	inequitable 	conduct 	defense 	and 	counterclaim
(Thirteenth 	Additional 	Defense 	and 	Fourth 	Counterclaim) 	are
STRICKEN AND DISMISSED WITH PREJUDICE;
• 	Amgen’s 	federal 	antitrust 	counterclaims 	(Sixth 	and 	Seventh
Counterclaims) 	are 	DISMISSED 	WITH 	PREJUDICE 	as 	to 	the
allegations relating to the ’099 patent and DISMISSED WITHOUT
PREJUDICE 	as 	to 	the 	allegations 	relating 	to 	the 	2024
Litigation Patents;
• 	Amgen’s 	UCL 	counterclaim 	(Eighth 	Counterclaim) 	is 	DISMISSED
WITH 	PREJUDICE 	as 	to 	the 	allegations 	relating 	to 	the 	’099
patent and DISMISSED WITHOUT PREJUDICE as to the allegations
relating to the 2024 Litigation Patents;
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• 	Amgen’s 	patent 	misuse 	defense 	and 	counterclaim 	(Fourteenth
Additional 	Defense 	and 	Fifth 	Counterclaim) 	are 	STRICKEN 	AND
DISMISSED WITH PREJUDICE;
• 	Amgen’s unclean hands defense (Fourth Additional Defense) is
STRICKEN WITH PREJUDICE;
• 	Regeneron’s 	Motion 	is 	DENIED 	with 	respect 	to 	Amgen’s 	laches
defense 	and 	counterclaim 	(Eleventh 	Additional 	Defense 	and
Third Counterclaim); and
• 	The following motions are DENIED AS MOOT: Regeneron’s Motion
to Bifurcate and Stay Amgen’s Antitrust Claims [ECF No. 691],
Amgen’s Motion for Leave to File a Sur-Reply in Opposition to
Regeneron’s 	Motion 	to 	Bifurcate 	and 	Stay 	[ECF 	No. 	715], 	and
Regeneron’s Conditional Motion to Compel Damages Discovery on
Amgen’s Antitrust Claims [ECF No. 823].
It is so ORDERED.
The Clerk is DIRECTED to transmit copies of this Order to counsel
of record.
DATED: July 7, 2026
____________________________
THOMAS S. KLEEH, CHIEF JUDGE
NORTHERN DISTRICT OF WEST VIRGINIA
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