Incyte Corporation, Incyte Holdings Corp. v. Sun Pharmaceutical Industries, Ltd., Sun Pharmaceutical Industries, Inc.

United States Court of Appeals
for the Federal Circuit
______________________
INCYTE CORPORATION, INCYTE HOLDINGS
CORP.,
Plaintiffs-Appellees
v.
SUN PHARMACEUTICAL INDUSTRIES, LTD., SUN
PHARMACEUTICAL INDUSTRIES, INC.,
Defendants-Appellants
______________________
2025-1162
______________________
Appeal from the United States District Court for the
District of New Jersey in No. 2:24-cv-06944-JXN-JBC,
Judge Julien X. Neals.
______________________
Decided: May 7, 2025
______________________
M ARK J. FELDSTEIN, Finnegan, Henderson, Farabow,
Garrett & Dunner, LLP, Washington, DC, argued for plain-
tiffs-appellees. Also represented by D ANIELLE ANDREA
D USZCZYSZYN, DANIEL F. ROLAND, JASON LEE ROMRELL; J.
D EREK MC CORQUINDALE, Reston, VA; M EGAN M EYERS,
M ARTIN DAVID WEINGARTEN, Atlanta, GA.
PAUL E. TORCHIA , Gibson, Dunn & Crutcher LLP, New
York, NY, argued for defendants-appellants. Also repre-
sented by CHARLOTTE JACOBSEN, JOSH K REVITT ; BLAINE H.
Case: 25-1162 Document: 49 Page: 1 Filed: 05/07/2025

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INCYTE CORP . v. SUN PHARMACEUTICAL INDUSTRIES, LTD. 2
EVANSON, Irvine, CA; ALEXANDER N. H ARRIS, Los Angeles,
CA; CHRISTINE RANNEY , Denver, CO.
______________________
Before M OORE, Chief Judge, PROST and HUGHES, Circuit
Judges.
M OORE , Chief Judge.
Sun Pharmaceutical Industries, Ltd. and Sun Pharma-
ceutical Industries, Inc. (collectively, Sun) appeal an order
from the United States District Court for the District of
New Jersey granting Incyte Corporation and Incyte Hold-
ings Corporation’s (collectively, Incyte) motion for a prelim-
inary injunction enjoining Sun from making, using, selling,
advertising, or distributing its drug Leqselvi. On April 9,
2025, we issued an order vacating the injunction with an
opinion to follow. For the following reasons, we reverse the
district court’s order.
BACKGROUND
Incyte owns U.S. Patent No. 9,662,335, which claims
deuterated versions of ruxolitinib, a Janus kinase (JAK)
modulator used to treat diseases associated with autoim-
mune disorders. ’335 patent at Abstract, 32:60–64, 68:4–9,
109:1–110:38. Claim 1 is representative:
1. A compound, which is 3-cyclopentyl-3-[4-(7H-
pyrrolo[2,3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl]pro-
panenitrile, wherein one or more hydrogen atoms
are replaced by deuterium; or a pharmaceutically
acceptable salt thereof.
Id. at 366:14–17.
In July 2024, Sun secured FDA approval for an oral
deuterated ruxolitinib product, branded as Leqselvi, to
treat alopecia areata (AA). J.A. 3. Sun was set to launch
Leqselvi in October 2024. J.A. 3–4. Prior to launching, In-
cyte sued Sun for allegedly infringing the ’335 patent and
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INCYTE CORP . v. SUN PHARMACEUTICAL INDUSTRIES, LTD. 3
moved for a preliminary injunction. J.A. 1801–42. The dis-
trict court granted Incyte’s motion for a preliminary injunc-
tion. J.A. 1–52. Sun appeals. We have jurisdiction
pursuant to 28 U.S.C. §§ 1292(c)(1) and 1295(a)(1).
D ISCUSSION
I.
We review the grant of a preliminary injunction accord-
ing to the law of the regional circuit, here the Third Circuit,
except for patent-specific issues, which we review accord-
ing to Federal Circuit law. Koninklijke Philips N.V. v. Tha-
les DIS AIS USA LLC, 39 F.4th 1377, 1379 (Fed. Cir. 2022).
The grant of a preliminary injunction is reviewed for an
abuse of discretion. Id. A district court abuses its discre-
tion when it makes a clear error of judgment in weighing
relevant factors or exercises its discretion based upon an
error of law or a clearly erroneous factual finding. Id.
To obtain a preliminary injunction, a party must show
“that [it] is likely to succeed on the merits, that [it] is likely
to suffer irreparable harm in the absence of preliminary
relief, that the balance of equities tips in [its] favor, and
that an injunction is in the public interest.” Luminara
Worldwide, LLC v. Liown Elecs. Co., 814 F.3d 1343, 1352
(Fed. Cir. 2016) (alterations in original) (quoting Winter v.
Nat. Res. Def. Council, Inc., 555 U.S. 7, 20 (2008)). A dis-
trict court’s finding of irreparable harm is reviewed to de-
termine whether it is clearly erroneous. See Ferring
Pharms., Inc. v. Watson Pharms., Inc., 765 F.3d 205, 218
(3d Cir. 2014); Whitaker By Whitaker v. Kenosha Unified
Sch. Dist. No. 1 Bd. of Educ., 858 F.3d 1034, 1045 (7th Cir.
2017); Texas v. United States Dep’t of Homeland Sec.,
123 F.4th 186, 211 (5th Cir. 2024); Sleep No. Corp. v.
Young, 33 F.4th 1012, 1018 (8th Cir. 2022).
Sun appeals the district court’s grant of a preliminary
injunction, arguing Incyte failed to show it is likely to
(1) suffer irreparable harm and (2) succeed on the merits.
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INCYTE CORP . v. SUN PHARMACEUTICAL INDUSTRIES, LTD. 4
Appellant Br. 22–58. Because the district court clearly
erred in its irreparable harm analysis, we do not reach
Sun’s likelihood of success arguments.
II.
A patentee can be irreparably harmed by an alleged in-
fringer’s improper “head start” and the loss of the “first
mover advantage” because the alleged infringer can cap-
ture market share and secure a competitive lead. Bio-Rad
Lab’ys, Inc. v. 10X Genomics Inc., 967 F.3d 1353, 1378 (Fed.
Cir. 2020); John C. Jarosz, Jorge L. Contreras & Robert L.
Vigil, Preliminary Injunctive Relief in Patent Cases: Re-
pairing Irreparable Harm, 31 T EX . INTELL. PROP. L.J. 63,
124–25 (2022) (“A first mover advantage can be thought of
as a firm’s benefits from being the first to market a new
product or service. . . . [L]oss of a first mover advantage
[can include] possible harm related to the loss of ‘sticky’
customer relationships.”). This economic principle can ap-
ply in the medical context when patients are unlikely to
switch treatments. See Natera, Inc. v. NeoGenomics
Lab’ys, Inc., 106 F.4th 1369, 1379 (Fed. Cir. 2024) (noting
that “continuity of care” for patients supports finding irrep-
arable harm based on infringing competitor’s plan to enter
the market). In this case, it is undisputed patients are un-
likely to switch treatments for AA. Appellee Br. 43; Dkt. 5
(Sun Motion to Expedite Appeal) at 13–14 (citing J.A. 9951
¶ 52 and J.A. 16851 ¶ 97).
Before the district court, Incyte provided five alterna-
tive theories for irreparable harm. J.A. 1829–42. Incyte’s
last theory, which it spent just two paragraphs developing,
was that Sun’s Leqselvi launch would give Sun an unjust
head start over Incyte in the AA market. J.A. 1841–42.
Incyte argued the head start would give Sun a longer lead
time and diminish the value of Incyte’s topical deuterated
ruxolitinib product currently in the early stages of develop-
ment. J.A. 1841–42; J.A. 10575, 10588. The district court
agreed with Incyte’s head start theory for its finding of
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INCYTE CORP . v. SUN PHARMACEUTICAL INDUSTRIES, LTD. 5
irreparable harm, expressly rejecting Incyte’s other theo-
ries. J.A. 26–45. The district court explained that “but for
Sun’s Leqselvi, Incyte’s ’335 patent would provide it with
the ability to bring a [deuterated ruxolitinib] AA treatment
first to market.” J.A. 41 (emphasis added). Accepting In-
cyte’s assertions regarding the development of its product,
there is no question this is a clearly erroneous fact finding.
The facts are undisputed. Sun is prepared to launch.
Oral Arg. 21:55–22:04.1 The ’335 patent expires in Decem-
ber 2026. And Incyte will not launch its product, under its
best-case scenario, until at least several years after its ’335
patent expires.2 J.A. 4 n.8; Appellee Br. 8. Because Incyte
cannot enjoin Sun from launching after its ’335 patent ex-
pires, Sun’s multi-year head start is inevitable regardless
of any injunction. Natera, 106 F.4th at 1378 (stating the
party seeking an injunction must “show it is likely to suffer
irreparable harm if the injunction is not granted”).
It was clearly erroneous for the district court to find
that Incyte would be first to market if its preliminary in-
junction were granted. At best, Incyte argues that, without
the injunction, Sun will receive an additional two years on
the market and cause Incyte irreparable harm due to its
loss of market share from this extended head start. Oral
Arg. at 13:29–13:55; Appellee Br. 43 (“An advantage of
even a few more years permits Sun to entrench itself
1 Available at https://oralarguments.cafc.uscourts.
gov/dfault.aspx?fl=25-1162_04092025.mp3.
2 Incyte provides two development timelines that
show different projected dates on which Incyte anticipates
filing a new drug application (NDA). Compare J.A. 10575,
with J.A. 10588. Counsel for Incyte believes the timeline
with the earlier projected NDA date is correct but could not
confirm. Oral Arg. at 16:19–19:08. Even assuming the ear-
lier projected date is correct, FDA approval would still not
occur until several years after the ’335 patent expires.
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INCYTE CORP . v. SUN PHARMACEUTICAL INDUSTRIES, LTD. 6
intractably in the market . . . causing unquantifiable harm
by locking up patients who will be lost to Incyte ‘forever.’”
(quoting J.A. 6805 ¶¶ 66–67)). Incyte fails to provide non-
speculative evidence that it will be irreparably harmed by
Sun’s launch under these circumstances where Sun’s
multi-year head start is inevitable.
Incyte argues the district court independently found ir-
reparable harm under its head start theory based on the
diminished value to Incyte’s investment in developing its
product. Appellee Br. 16–17; Oral Arg. 8:45–9:45 (citing
district court’s order at J.A. 43, 49). The district court’s
irreparable harm findings regarding investment-based
harm hinged on the same mistake of fact that its head start
finding was predicated on—that, absent an injunction, In-
cyte would be first to market. J.A. 41, 43 (“Sun’s premature
entrance into the AA market diminishes the value of [In-
cyte]’s investments in a topical AA product.”). For the same
reasons, the district court’s finding regarding irreparable
harm is clearly erroneous.
We hold that the district court clearly erred in finding
that Incyte established irreparable harm. We reverse the
district court’s grant of the preliminary injunction.
REVERSED
COSTS
Costs to Sun.
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