Case: 22-2217 Document: 61 Page: 1 Filed: 07/24/2023
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`
`
`United States Court of Appeals
`for the Federal Circuit
`______________________
`
`UNITED THERAPEUTICS CORPORATION,
`Plaintiff-Cross-Appellant
`
`v.
`
`LIQUIDIA TECHNOLOGIES, INC.,
`Defendant-Appellant
`______________________
`
`2022-2217, 2023-1021
`______________________
`
`Appeals from the United States District Court for the
`District of Delaware in No. 1:20-cv-00755-RGA-JLH, Judge
`Richard G. Andrews.
`______________________
`
`Decided: July 24, 2023
`______________________
`
`SANYA SUKDUANG, Cooley LLP, Washington, DC, ar-
`gued for defendant-appellant.
` Also represented by
`JONATHAN DAVIES; DEEPA KANNAPPAN, Palo Alto, CA; ERIK
`BENTON MILCH, Reston, VA.
`
` WILLIAM M. JAY, Goodwin Procter LLP, Washington,
`DC, argued for plaintiff-cross-appellant. Also represented
`by WILLIAM COVINGTON JACKSON, JAIME SANTOS,
`ROHINIYURIE TASHIMA, JENNY J. ZHANG; GERARD JUSTIN
`CEDRONE, Boston, MA; ADAM WILLIAM BURROWBRIDGE.
`McDermott Will & Emery, LLP, Washington, DC;
`DOUGLAS H. CARSTEN, ARTHUR PAUL DYKHUIS, Irvine, CA;
`
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`UNITED THERAPEUTICS CORPORATION v.
` LIQUIDIA TECHNOLOGIES, INC.
`
`SHAUN R. SNADER, United Therapeutics Corporation,
`Washington, DC.
` ______________________
`
`Before LOURIE, DYK, and STOLL, Circuit Judges.
`LOURIE, Circuit Judge.
`Liquidia Technologies, Inc. (“Liquidia”) appeals from a
`decision of the United States District Court for the District
`of Delaware holding that (1) claims 1, 4, and 6–8 of U.S.
`Patent 10,716,793 (“the ’793 patent”) are not invalid and
`are infringed by Liquidia and (2) claims 1–3 of U.S. Patent
`9,593,066 (“the ’066 patent”) are invalid as anticipated, but
`are otherwise infringed by Liquidia. United Therapeutics
`Corporation (“United Therapeutics”) cross-appeals from
`the court’s decision holding that (1) claims 1–3, 6, and 9 of
`the ’066 patent are invalid as anticipated and (2) claims 6,
`8, and 9 of the ’066 patent are not infringed by Liquidia.
`See United Therapeutics Corp. v. Liquidia Techs., Inc., 624
`F. Supp. 3d 436 (D. Del. 2022) (“Decision”). For the reasons
`provided below, we affirm.
`BACKGROUND
`United Therapeutics holds New Drug Application
`(“NDA”) No. 022387 for Tyvaso®, an inhaled solution for-
`mulation of treprostinil approved for the treatment of pul-
`monary hypertension (“PH”). Pulmonary hypertension is a
`potentially life-threatening condition characterized gener-
`ally by abnormally high blood pressure in the lungs. For
`many patients, treprostinil is used in treating pulmonary
`hypertension because it is a vasodilator that reduces vaso-
`constriction in the pulmonary vasculature, thereby de-
`creasing blood pressure.
`Experts consider that there are five subgroups of pul-
`monary hypertension: Group 1, pulmonary arterial hyper-
`tension (“PAH”); Group 2, pulmonary venous hypertension,
`i.e., pulmonary hypertension related to left-heart disease;
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`UNITED THERAPEUTICS CORPORATION v.
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`Group 3, pulmonary hypertension associated with disor-
`ders damaging the lungs; Group 4, pulmonary hyperten-
`sion caused by chronic thrombotic or embolic disease,
`including chronic blood clots in the lungs; and Group 5, a
`miscellaneous category for conditions that do not fit well
`into the other four subgroups. Groups 1, 3, 4, and 5 are
`caused by conditions affecting the pulmonary arteries or
`precapillary vessels of the lungs (“precapillary PH”), while
`Group 2 typically develops as a result of a cardiac-based
`etiology (“postcapillary PH”). Due to differing etiologies,
`each group may require group-specific treatment.
`United Therapeutics owns the ’793 and ’066 patents,
`which are generally directed to methods of treating pulmo-
`nary hypertension and to pharmaceutical compositions
`comprising treprostinil. The ’793 and ’066 patents are
`listed in the FDA’s Orange Book for Tyvaso.
`
`Liquidia filed NDA No. 213005 for Yutrepia™ under
`§ 505(b)(2) of the Food, Drug, and Cosmetic Act (codified at
`21 U.S.C. § 355(b)(2)). 1 Yutrepia is a dry powder
`
`1 Under the Drug Price Competition and Patent
`Term Restoration Act of 1984 (the Hatch-Waxman amend-
`ments to the Food, Drug, and Cosmetic Act), an NDA filed
`under § 505(b)(2) contains full reports of investigations of
`safety and effectiveness, where at least some of the infor-
`mation used for approval comes from studies that were not
`conducted for or by the applicant. Such an NDA is one of
`two abbreviated approval pathways introduced by the
`Hatch-Waxman amendments, the other being an abbrevi-
`ated new drug application (“ANDA”) filed under § 505(j)
`(codified at 21 U.S.C. § 355(j)). 35 U.S.C. § 271(e)(2), the
`statutory provision delineating acts of infringement, covers
`both types of applications: “It shall be an act of infringe-
`ment to submit . . . an application under section 505(j) of
`the Federal Food, Drug, and Cosmetic Act or described in
`
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`UNITED THERAPEUTICS CORPORATION v.
` LIQUIDIA TECHNOLOGIES, INC.
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`inhalation formulation of treprostinil but is not a generic
`version of any currently marketed drug. Pursuant to §
`505(c)(3)(C) (codified at 21 U.S.C. § 355(c)(3)(C)), United
`Therapeutics sued Liquidia within 45 days of receipt of no-
`tice of Liquidia’s NDA in the United States District Court
`for the District of Delaware alleging infringement of the
`’066 patent. J.A. 171, 190. In addition, after Liquidia filed
`its NDA, United Therapeutics filed another patent applica-
`tion that eventually issued as the ’793 patent, which was
`subsequently added to the district court litigation. J.A.
`208.
`In parallel, Liquidia filed a petition for inter partes re-
`view (“IPR”) of the ’793 patent, alleging that all claims
`would have been unpatentable as obvious over prior art at
`the time of the invention. On July 19, 2022, the Board is-
`sued a Final Written Decision finding all claims of the ’793
`patent unpatentable as obvious. Liquidia Techs., Inc. v.
`United Therapeutics Corp., No. IPR2021-00406, 2022 WL
`2820717 (P.T.A.B. July 19, 2022). United Therapeutics
`filed a Request for Rehearing, challenging whether various
`asserted references qualified as prior art. J.A. 36648. In
`its Rehearing Decision, the Board found that the references
`were prior art, again holding the claims of the ’793 patent
`unpatentable as obvious. United Therapeutics filed a No-
`tice of Appeal in that case on April 26, 2023. Liquidia filed
`a motion for expedited appeal, which has been denied. The
`appeal is currently pending in this court.
`I. The ’793 Patent
`The ’793 patent is directed to a method of treating pul-
`
`monary hypertension comprising inhalation of treprostinil.
`Asserted claim 1 of the ’793 patent is the only independent
`claim and reads as follows:
`
`
`section 505(b)(2) of such Act for a drug claimed in a patent
`or the use of which is claimed in a patent[.]”
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`UNITED THERAPEUTICS CORPORATION v.
`LIQUIDIA TECHNOLOGIES, INC.
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`1. A method of treating pulmonary hyper-
`tension comprising administering by inhala-
`tion to a human suffering from pulmonary
`hypertension a therapeutically effective sin-
`gle event dose of a formulation comprising
`treprostinil or a pharmaceutically acceptable
`salt thereof with an
`inhalation device,
`wherein the therapeutically effective single
`event dose comprises from 15 micrograms to
`90 micrograms of treprostinil or a pharmaceu-
`tically acceptable salt thereof delivered in 1 to
`3 breaths.
`’793 patent at col. 18 ll. 23–31.
`The additional asserted dependent claims include lim-
`itations directed to dry powder inhalers (claim 4), powder
`formulations (claim 6), powder formulations comprising
`particles less than 5 micrometers in diameter (claim 7), and
`formulations containing no metacresol (claim 8). See id. col.
`18 ll. 36–37, 40–45.
`In the district court, United Therapeutics argued that,
`although Liquidia’s proposed product had not yet been
`marketed, when marketed, it (1) would directly infringe
`claims 1, 4, and 6–8 of the ’793 patent and (2) would also
`induce infringement of those claims. Liquidia responded
`that the asserted claims were invalid as lacking adequate
`enablement and written description under 35 U.S.C. § 112.
`
`The district court found that United Therapeutics
`showed that a single administration of treprostinil, as re-
`quired by claim 1, improves a patient’s hemodynamics, es-
`tablishing that administration of Liquidia’s Yutrepia,
`comprising treprostinil, at the claimed doses will also im-
`prove a patient’s hemodynamics. The court concluded that
`United Therapeutics thus proved by a preponderance of the
`evidence that the administration of Yutrepia will directly
`infringe claims 1, 4, and 6–8 of the ’793 patent.
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`UNITED THERAPEUTICS CORPORATION v.
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`The district court also concluded that Liquidia’s argu-
`
`ment that it lacked specific intent to induce infringement
`lacked merit. Liquidia argued that, because the Yutrepia
`label does not encourage administration of a therapeuti-
`cally effective single event dose, it does not induce infringe-
`ment. The court noted that the label does not need to
`provide hemodynamic data to constitute inducement of in-
`fringement; instead, it merely needs to instruct doctors and
`patients to administer a therapeutically effective single
`event dose. The court found that the label’s instructions
`will inevitably lead to the administration of a therapeuti-
`cally effective single event dose. The court thus concluded
`that United Therapeutics proved by a preponderance of the
`evidence that Liquidia will induce infringement of claims
`1, 4, and 6–8 of the ’793 patent.
`
`The district court further found that the asserted
`claims were not invalid for lack of enablement or written
`description. First, the court construed “treating pulmo-
`nary hypertension” as encompassing all five groups of pul-
`monary hypertension, noting that the specification of
`the ’793 patent expressly includes all five groups when de-
`scribing “pulmonary hypertension.” Second, the court
`found that a skilled artisan would not need to engage in
`undue experimentation to practice the full scope of the
`claimed treatment of pulmonary hypertension, despite po-
`tential safety concerns in treating Group 2 PH patients,
`and that the claims did not require safety and efficacy.
`Third, the court found that the claims were not invalid for
`lack of written description, finding that a skilled artisan
`would, based on the specification, understand that trepros-
`tinil would effectively vasodilate the pulmonary vascula-
`ture, improve hemodynamics, and treat a patient’s
`elevated pulmonary blood pressure. As a result of the
`court’s findings that the claims were not invalid but were
`infringed, the court stayed approval of Liquidia’s NDA for
`Yutrepia until May 5, 2027, the expiration date of the ’793
`patent.
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`UNITED THERAPEUTICS CORPORATION v.
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`II. The ’066 Patent
`The ’066 patent is directed to a pharmaceutical compo-
`sition comprising treprostinil and a process of preparing a
`pharmaceutical product comprising treprostinil.
`Asserted claim 1 of the ’066 patent reads as follows:
`1. A pharmaceutical composition compris-
`ing treprostinil or a pharmaceutically ac-
`ceptable salt
`thereof, said composition
`prepared by a process comprising providing a
`starting batch of treprostinil having one or
`more impurities resulting from prior alkyla-
`tion and hydrolysis steps, forming a salt of
`treprostinil by combining the starting batch
`and a base, isolating the treprostinil salt, and
`preparing a pharmaceutical composition com-
`prising treprostinil or a pharmaceutically ac-
`ceptable salt thereof
`from the
`isolated
`treprostinil salt, whereby a level of one or
`more impurities found in the starting batch of
`the treprostinil is lower in the pharmaceutical
`composition, and wherein said alkylation is
`alkylation of benzindene triol.
`’066 patent at col. 17 ll. 51–63.
`Asserted claim 6 of the ’066 patent reads:
`6. The pharmaceutical composition of
`claim 1, wherein the isolated salt is stored at
`ambient temperature.
`Id. col. 18 ll. 34–35.
`Asserted claim 8 of the ’066 patent reads:
`8. A process of preparing a pharmaceutical
`product comprising treprostinil or a pharma-
`ceutically acceptable salt thereof, comprising
`alkylating a triol intermediate of the formula:
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`UNITED THERAPEUTICS CORPORATION v.
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`hydrolyzing the resulting compound to form
`treprostinil, forming a salt of treprostinil sta-
`ble at ambient temperature, storing the
`treprostinil salt at ambient temperature, and
`preparing a pharmaceutical product from the
`treprostinil salt after storage, wherein the
`pharmaceutical product comprises treprosti-
`nil or a pharmaceutically acceptable salt
`thereof.
`Id. col. 18 ll. 38–61.
`Additional asserted dependent claims are directed to
`crystalline forms (claim 2), a base selected from the group
`consisting of sodium, ammonia, potassium, calcium, etha-
`nolamine, diethanolamine, N-methylglucamine, and cho-
`line (claim 3), and a pharmaceutical product prepared by
`the process recited in claim 8 (claim 9). See id. col. 17 ll.
`64–67; col. 18 ll. 27–28, 62–63.
`In the district court, United Therapeutics argued that
`Liquidia infringed claims 1–3, 6, 8, and 9 of the ’066 patent.
`Liquidia responded that claims 1–3, 6, and 9 were invalid
`as anticipated by Moriarty2 and that claims 1–3 and 6 were
`invalid as lacking written description support. Liquidia did
`not challenge the validity of claim 8, which is a chemical
`
`
`2 R.M. Moriarty et al., The Intramolecular Asymmet-
`ric Pauson-Khand Cyclization as a Novel and General Ste-
`reoselective Route to Benzindene Prostacyclins: Synthesis of
`UT-15 (Treprostinil), 69 J. ORGANIC CHEM. 1890 (2004).
`
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`UNITED THERAPEUTICS CORPORATION v.
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`9
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`process claim, in contrast to the other claims that are di-
`rected to compositions.
`The district court found that United Therapeutics
`showed by a preponderance of the evidence that Liquidia’s
`Yutrepia would infringe claims 1–3 of the ’066 patent be-
`cause Yutrepia met the impurities limitations of claim 1.
`But the court also found that claims 1–3, 6, and 9 were in-
`valid as anticipated by Moriarty. Moriarty discloses the
`synthesis of analogues of benzindene prostacyclins, includ-
`ing treprostinil, which is designated in the publication as
`UT-15. Moriarty at 1890, 1892. The court also found that
`Liquidia showed by clear and convincing evidence that the
`claimed treprostinil product is functionally and structur-
`ally the same as the UT-15 treprostinil disclosed in Mori-
`arty. The court thus concluded that claims 1–3 would have
`been infringed by Liquidia, but for the finding of anticipa-
`tion, and that claims 6 and 9 were invalid as anticipated by
`Moriarty but not infringed by Liquidia.
`In finding a lack of infringement of claim 6, the court
`construed the terms “ambient temperature” as room tem-
`perature (equal to or less than the range of 15°C to 30°C)
`and “stored”/“storing”/“storage” to have its plain and ordi-
`nary meaning. Using these constructions, the court deter-
`mined that United Therapeutics failed to show by a
`preponderance of the evidence that Liquidia’s Yutrepia
`production process stored treprostinil at ambient tempera-
`ture, and therefore found that claims 6, 8, and 9 were not
`infringed. The court further found that any storage be-
`tween steps of Liquidia’s manufacturing process did not
`meet the limitations of claims 8 and 9, which require stor-
`age of treprostinil before preparing a pharmaceutical prod-
`uct.
`The district court also found that the specification pro-
`vided adequate written description support for the impuri-
`ties limitation in claim 1, and that a skilled artisan would
`understand that the inventors were in possession of the
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`UNITED THERAPEUTICS CORPORATION v.
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`composition with the claimed impurities. The court thus
`concluded that Liquidia did not prove by clear and convinc-
`ing evidence that claims 1–3 and 6 of the ’066 patent were
`invalid for lack of written description.
`In summary, the district court concluded that (1)
`claims 1, 4, and 6–8 of the ’793 patent were not invalid and
`were infringed by Liquidia; (2) claims 1–3 of the ’066 patent
`were invalid as anticipated by Moriarty and would have
`been infringed by Liquidia but for the finding of anticipa-
`tion; (3) claims 6 and 9 of the ’066 patent were invalid as
`anticipated by Moriarty and not infringed by Liquidia; and
`(4) claim 8 of the ’066 patent was not invalid and not in-
`fringed by Liquidia. Liquidia appealed, and United Ther-
`apeutics cross-appealed. We have jurisdiction under 28
`U.S.C. § 1295(a)(1).
`
`DISCUSSION
`Liquidia raises five issues on appeal. First, Liquidia
`
`contends that the district court erred in construing the
`claim limitation “treating pulmonary hypertension” in
`claim 1 of the ’793 patent not to include safety and efficacy.
`Second, Liquidia argues that the court erred in finding the
`asserted claims of the ’793 patent enabled. Third, Liquidia
`contends that the court clearly erred in finding the asserted
`claims of the ’793 patent supported by written description.
`Fourth, Liquidia contends that the court clearly erred in
`finding Liquidia liable for induced infringement of claims
`1, 4, and 6–8 of the ’793 patent. Fifth, Liquidia argues that
`the court clearly erred in finding claims 1–3 of the ’066 pa-
`tent to be infringed.
`United Therapeutics raises two issues on cross-appeal.
`First, United Therapeutics asserts that the district court
`clearly erred in finding that Liquidia does not infringe
`claims 6 and 8 of the ’066 patent. Second, United Thera-
`peutics contends that the court clearly erred in finding that
`claims 1–3, 6, and 9 of the ’066 patent are invalid as
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`UNITED THERAPEUTICS CORPORATION v.
`LIQUIDIA TECHNOLOGIES, INC.
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`11
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`anticipated by Moriarty. We address each appeal and
`cross-appeal argument in turn.
`Infringement is a question of fact that we review, after
`a bench trial, for clear error. Eli Lilly & Co. v. Teva Paren-
`teral Meds., Inc., 845 F.3d 1357, 1364 (Fed. Cir. 2017). A
`patent is directly infringed when a person “without author-
`ity makes, uses, offers to sell, or sells any patented inven-
`tion, within the United States or imports into the United
`States any patented invention during the term of the pa-
`tent.” 35 U.S.C. § 271(a). “Whoever actively induces in-
`fringement of a patent shall be liable as an infringer.” Id.
`§ 271(b).
`We review district court findings of anticipation under
`35 U.S.C. § 102 and satisfaction of the written description
`requirement under 35 U.S.C. § 112 for clear error. Nuvo
`Pharms. (Ir.) Designated Activity Co. v. Dr. Reddy’s Lab’ys
`Inc., 923 F.3d 1368, 1376 (Fed. Cir. 2019) (written descrip-
`tion); Forest Lab’ys, Inc. v. Ivax Pharms., Inc., 501 F.3d
`1263, 1268 (Fed. Cir. 2007) (anticipation). Enablement “is
`a question of law” that we review de novo after a bench trial.
`Auto. Techs. Int’l, Inc. v. BMW of N. Am., Inc., 501 F.3d
`1274, 1281 (Fed. Cir. 2007). We review questions of claim
`construction de novo but review any underlying facts for
`clear error. Markman v. Westview Instruments, Inc., 52
`F.3d 967, 979, 991 (Fed. Cir. 1995); Eli Lilly & Co. v. Hos-
`pira, Inc., 933 F.3d 1320, 1328 (Fed. Cir. 2019).
`I. The ’793 Patent
`A.
` We first consider Liquidia’s challenge to the district
`court’s determination that the meaning of “treating pulmo-
`nary hypertension” does not require a showing of safety
`and efficacy. It asserts that a skilled artisan would under-
`stand the plain and ordinary meaning of “treating pulmo-
`nary hypertension”
`to encompass a method
`that
`accomplishes that goal safely and effectively. It asserts
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`UNITED THERAPEUTICS CORPORATION v.
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`that the parties’ experts agreed that treatment with
`treprostinil, a vascular dilator, would not benefit Group 2
`PH patients. It further asserts that while the specification
`of the ’793 patent states that the treatment does not result
`in significant side effects, ’793 patent at col. 5 ll. 16–20, and
`that administration of treprostinil is safe, id. col. 9 ll. 30–
`31, its expert testified that a skilled artisan would have
`concerns about administering inhaled treprostinil to Group
`2 PH patients and that at least one earlier study, in which
`a treprostinil-like prostacyclin was administered to Group
`2 PH patients, failed due to increased mortality.
` United Therapeutics responds that the district court
`did not err in finding that the claimed administration of
`treprostinil would improve hemodynamics and hence treat
`a patient’s elevated pulmonary blood pressure, including
`Group 2 PH patients. It asserts that Liquidia attempts to
`import limitations into the claims and that nothing in the
`specification requires the importation of safety and efficacy
`limitations into the claims. Finally, United Therapeutics
`asserts that while Liquidia’s statements that a skilled ar-
`tisan would have safety concerns in treating Group 2 PH
`patients with treprostinil may factor into Food and Drug
`Administration (“FDA”) approval, they do not factor into
`claim interpretation.
`
`As a threshold matter, we agree with the district court
`that “treating pulmonary hypertension” includes treating
`all five groups of pulmonary hypertension patients. The
`court did not err in finding that the specification encom-
`passes all five groups when describing “pulmonary hyper-
`tension.” In fact, the specification does not limit the scope
`of “pulmonary hypertension” to any particular subset of
`pulmonary hypertension patients. It refers to both “preca-
`pillary pulmonary hypertension” and “pulmonary hyper-
`tension,” which, as the court found, demonstrates that the
`inventors view precapillary PH only as a subset of the
`broadly claimed “pulmonary hypertension.” Thus, “treat-
`ing pulmonary hypertension” includes treating all five
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`groups of pulmonary hypertension. See ’793 patent at col.
`9 ll. 36–37, col. 12 ll. 64–65, col. 16 ll. 64–65.
`While the claims require “treating pulmonary hyper-
`tension comprising administering . . . a therapeutically ef-
`fective single event dose of a formulation comprising
`treprostinil,” Decision, at 467, the district court gave the
`phrase “therapeutically effective” a limiting construction.
`The district court held, and Liquidia does not challenge on
`appeal, that a person of ordinary skill in the art “would un-
`derstand the plain and ordinary meaning of ‘therapeuti-
`cally effective single dose’ to be a dose given in a single
`treatment session that causes an improvement in a pa-
`tient’s hemodynamics (reduced PAP or PVR).” Id. at 461;
`Appellee’s Br. 39. We need not address whether the district
`court’s construction was correct because Liquidia, on ap-
`peal, does not challenge that construction. Read in context,
`the claim language “treating pulmonary hypertension”
`does not import any additional efficacy limitations or any
`safety limitations.
`Absent incorporation of safety and efficacy require-
`ments in the claims, Liquidia’s argument concerning the
`safety and efficacy of treating Group 2 PH patients is not
`before us. Questions of safety and efficacy in patent law
`have long fallen under the purview of the FDA. In re Brana,
`51 F.3d 1560, 1567 (Fed. Cir. 1995) (noting that “the re-
`quirements under the law for obtaining a patent” are dif-
`ferent from “the requirements for obtaining government
`approval to market a particular drug for human consump-
`tion”); Scott v. Finney, 34 F.3d 1058, 1063 (Fed. Cir. 1994)
`(“Testing for the full safety and effectiveness . . . is more
`properly left to the [FDA]. Title 35 does not demand that
`such human testing occur within the confines of Patent and
`Trademark Office (PTO) proceedings.”); In re Anthony, 414
`F.2d 1383, 1395 (CCPA 1969) (“Congress has given the re-
`sponsibility to the FDA, not to the Patent Office, to deter-
`mine in the first instance whether drugs are sufficiently
`safe for use that they can be introduced in the commercial
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`market . . . .”). We decline to insert the FDA’s responsibil-
`ities into claims by importing requirements where they do
`not recite such limitations.
`B.
` We next turn to Liquidia’s challenge to the district
`court’s finding that the claims of the ’793 patent are ade-
`quately enabled and supported by written description.
`Liquidia argues that the specification of the ’793 patent
`provides no guidance or examples of treating Group 2 PH
`patients, and thus that a skilled artisan would have to en-
`gage in undue experimentation to practice the full scope of
`the claimed invention (i.e., treating Group 2 PH patients).
`
`Liquidia further argues that, even if the district court’s
`construction of “treating pulmonary hypertension” as not
`requiring safety was proper, the claims of the ’793 patent
`would still not be enabled because any changes in hemody-
`namics caused by inhalation of treprostinil would provide
`no benefit to Group 2 PH patients. Thus, a skilled artisan
`would not conclude that the ’793 patent claims are enabled
`to the full scope of the claimed invention.
` United Therapeutics responds that the district court
`did not err in concluding that Liquidia failed to show a lack
`of enablement. It contends that Liquidia failed to show by
`clear and convincing evidence that enablement would re-
`quire undue experimentation with respect to Group 2 PH.
`Further, even if the specification fails to describe how
`to treat Group 2 PH patients with treprostinil, United
`Therapeutics asserts, claims are not required to carve out
`all possible inoperative embodiments in a claim in order to
`avoid that claim being found not to be enabled. United
`Therapeutics asserts that if a skilled artisan has the infor-
`mation to limit the claims to operative embodiments, then
`the claims are not invalid. Here, United Therapeutics as-
`serts, the skilled artisan has that information.
`
`

`

`Case: 22-2217 Document: 61 Page: 15 Filed: 07/24/2023
`
`UNITED THERAPEUTICS CORPORATION v.
`LIQUIDIA TECHNOLOGIES, INC.
`
`15
`
`Liquidia also challenges the district court’s finding that
`the claims are supported by an adequate written descrip-
`tion. Liquidia argues that the ’793 patent never describes
`treating Group 2 PH patients with inhaled treprostinil, but
`only Group 1, 3, and 4 patients, all of whom have precapil-
`lary PH. Thus, Liquidia contends, there is no information
`in the ’793 patent specification sufficient for a skilled arti-
`san to conclude that the inventors were in possession of a
`method of treating Group 2 PH patients with inhaled
`treprostinil.
`
`Liquidia further argues that, even if the district court
`correctly construed “treating pulmonary hypertension” not
`to require a showing of safety, the claims still are not sup-
`ported by written description because vasodilation of the
`pulmonary vasculature is not effective in treating Group 2
`PH patients. Thus, Liquidia contends, a skilled artisan
`would have understood that the inventors did not invent or
`possess a method of treating Group 2 PH patients.
`United Therapeutics responds that the district court
`did not clearly err in finding the claims of the ’793 patent
`supported by an adequate written description. United
`Therapeutics argues that Liquidia’s written description ar-
`guments fail for largely the same reasons as its enablement
`arguments. In particular, United Therapeutics asserts
`that the court did not err in holding that a skilled artisan
`would understand a therapeutically effective dose to be one
`that improves a patient’s hemodynamics. United Thera-
`peutics further contends that, although a physician may or
`may not decide to administer treprostinil to a Group 2 PH
`patient, that decision would be informed by FDA guidance,
`not the written description in the specification.
`We agree with United Therapeutics that the claims are
`adequately enabled as they were construed by the district
`court. The specification of the ’793 patent sufficiently ena-
`bles the scope of the claims. See, e.g., ’793 patent at col. 7
`ll.
`7–67
`(providing
`details
`on
`administration,
`
`

`

`Case: 22-2217 Document: 61 Page: 16 Filed: 07/24/2023
`
`16
`
`UNITED THERAPEUTICS CORPORATION v.
` LIQUIDIA TECHNOLOGIES, INC.
`
`concentrations, and dosages of inhaled treprostinil for
`treating patients with pulmonary hypertension); id. col. 9
`ll. 5–49 (describing an open label study upon acute safety,
`tolerability, and hemodynamic effects of inhaled treprosti-
`nil delivered over the course of a few seconds). While the
`court credited expert testimony concluding that a physi-
`cian may have safety concerns in treating Group 2 PH pa-
`tients with treprostinil and other vasodilators, see Decision,
`at 466–67, the court also found that the record demon-
`strates that the claimed administration of treprostinil vas-
`odilates
`the pulmonary vasculature and
`reduces
`pulmonary blood pressure even in Group 2 PH patients, id.
`at 468. The court properly relied on expert testimony and
`record evidence to conclude that a skilled artisan would un-
`derstand that the claimed administration of treprostinil
`would vasodilate the pulmonary vasculature, improve he-
`modynamics, and in this way for a single dose, treat a pa-
`tient’s elevated pulmonary blood pressure independent of
`the type (i.e., group) of pulmonary hypertension patient. Id.
`That was all that the claims require under the district
`court’s construction because, again, the parties do not dis-
`pute that a “therapeutically effective single event dose” is
`defined by “an improvement in a patient’s hemodynamics
`(reduced PAP or PVP).” That a study—administering
`treprostinil-like prostacyclins to Group 2 PH patients—
`failed due to increased mortality, yet showed “improve-
`ment in a patient’s hemodynamics,” may be an issue for the
`FDA. But our focus is on the claimed invention. And on
`this record, with the district court’s claim construction, the
`claims are adequately enabled.
` We also agree with United Therapeutics that the dis-
`trict court did not clearly err in finding that the claims of
`the ’793 patent are supported by an adequate written de-
`scription. Written description requires that the specifica-
`tion reasonably convey to those skilled in the art that the
`inventor had possession of the claimed invention as of the
`filing date. Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d
`
`

`

`Case: 22-2217 Document: 61 Page: 17 Filed: 07/24/2023
`
`UNITED THERAPEUTICS CORPORATION v.
`LIQUIDIA TECHNOLOGIES, INC.
`
`17
`
`1336, 1351 (Fed. Cir. 2010) (en banc). As the court noted,
`the ’793 patent claims require “treating pulmonary hyper-
`tension comprising administering . . . a therapeutically ef-
`fective single event dose of a formulation containing
`treprostinil,” Decision, at 466–67, and the specification de-
`scribes that. In other words, the specification shows pos-
`session for the claimed invention under the district court’s
`construction.
`
`Liquidia essentially asks us to treat Group 2 PH as a
`claimed species within a larger genus (i.e., all five groups
`of pulmonary hypertension). But analogizing a subset of
`patients having a variant of a particular disease to tradi-
`tional genus and species claims is inapt. It would be i