WO2020247756A1

WO2020247756A1 - Small molecules to relax uterine smooth muscle contractions

Info

Publication number: WO2020247756A1
Application number: PCT/US2020/036334
Authority: WO
Inventors: Ivan PUSHKARSKY; Yao Wang
Original assignee: Forcyte Biotechnologies, Inc.
Priority date: 2019-06-05
Filing date: 2020-06-05
Publication date: 2020-12-10

Abstract

The present disclosure provides, among other things, methods of treating preterm labor and/or methods of reducing the strength, duration, or frequency of contractions in a subject in need thereof. The present disclosure provides, among other things, methods that include administering to a subject a contraction-reducing agent such as niclosamide or a niclosamide analog.

Description

SMALL MOLECULES TO RELAX UTERINE SMOOTH MUSCLE CONTRACTIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

62/857,800, filed June 5, 2019, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] Early labor is associated with higher rates of hospitalization, disability, and death of newborns. Preterm labor can be caused by, e.g., infection, bleeding, hormonal changes, and uterine stretching, among other causes. Various factors can also increase the likelihood that a pregnant woman will have preterm labor. It has been estimated that approximately 15 million babies are bom preterm every year, and that about 1 out of 10 US births are preterm. Globally, according to certain reports, prematurity is the leading cause of death in children under the age of 5 years. It has been observed that, in almost all countries with reliable data, preterm birth rates are increasing.

SUMMARY

[0003] The present disclosure provides, among other things, contraction-regulatory compounds useful in the treatment of preterm labor and methods of using the same for treatment of preterm labor. The present disclosure provides compositions and methods for the treatment of preterm labor and prevention of preterm birth. In particular, the present disclosure provides agents which suppress, reverse, or reduce contractions or contractile tone of the uterus (e.g., the uterus of a human, such as a pregnant female human, or of a non-human mammal, such as a pregnant female non-human mammal). The disclosure further extends to the use of compounds which act as tocolytics for the treatment of preterm labor.

[0004] Contraction-regulatory compounds of the present disclosure include contraction- regulatory compounds are described generally herein, and are illustrated by the classes, subclasses, and species disclosed herein. The present disclosure includes niclosamide and niclosamide analogs as contraction-regulatory compounds useful for the treatment of preterm labor, and methods of using the same for treatment of preterm labor.

[0005] In at least one aspect, the present disclosure provides a method of treating preterm labor in a subject in need thereof, the method including administering to the subject a contraction-reducing compound, where the contraction-reducing compound is selected from: (a) niclosamide or a niclosamide analog; (b) a compound selected from dihydroouabain, piperlongumine, stevioside, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, lanatoside C, proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159; and/or (c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

[0006] In at least one aspect, the present disclosure provides a method of reducing contractions in a subject in need thereof, the method including administering to the subject a contraction-reducing compound, where the contraction-reducing compound is selected from: (a) niclosamide or a niclosamide analog; (b) a compound selected from dihydroouabain, piperlongumine, stevioside, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, lanatoside C, proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159; and/or (c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

[0007] In various embodiments of methods of the present disclosure, the contraction- reducing compound is niclosamide. In various embodiments of methods of the present disclosure, the contraction-reducing compound is a niclosamide analog according to Formula I. In various embodiments of methods of the present disclosure, the contraction-reducing compound is a niclosamide analog according to any one of Formulas I-a, I-b, I-c, I-d, I-e, I-f, or I-g. In various embodiments of methods of the present disclosure, the contraction-reducing compound is a niclosamide analog according to any one of Formulas 1-1, 1-2, 1-3, 1-4, 1-5, 1-6 , 1- 7, 1-8, 1-9, or I- 10. In various embodiments of methods of the present disclosure, the

contraction-reducing compound is a niclosamide analog according to Formula II. In various embodiments of methods of the present disclosure, the contraction-reducing compound is selected from piperlongumine, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, GR 127935 hydrochloride hydrate, NAN- 190 hydrobromide, and/or MRS 2159. In various embodiments of methods of the present disclosure, the contraction-reducing compound is a cardiac glycoside according to the cardiac glycoside structure of FIG. 6. In various embodiments of methods of the present disclosure, the contraction-reducing compound is selected from dihydroouabain, stevioside, lanatoside C, and proscillaridin A.

[0008] In various embodiments of methods of the present disclosure, the subject is a pregnant human female and has completed less than 37 weeks of pregnancy, optionally where the subject has completed more than 20, 21, 22, 23, 24, or 25 weeks of pregnancy. In various embodiments of methods of the present disclosure, the subject has experienced a first contraction and a second contraction, where the first and second contractions are no more than 10 minutes apart. In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions in the subject, for example, where the strength, frequency, or duration of contractions is measured by a tocodynometer, electronic fetal monitor, intrauterine pressure catheter (IUPC), electrical uterine myography (EUM), and/or

electrohysterography. In various embodiments of methods of the present disclosure, the subject has completed less than 37 weeks of pregnancy and has one or more symptoms of preterm labor, where the symptom of preterm labor is selected from vaginal discharge, pelvic pressure, cramping, backache, nausea, vomiting, and/or diarrhea, optionally where the subject has completed more than 20, 21, 22, 23, 24, or 25 weeks of pregnancy. In various embodiments of methods of the present disclosure, the treatment reduces the symptoms of preterm labor. In various embodiments of methods of the present disclosure, the subject has a risk factor for preterm labor, where the risk factor is selected from one or more of past preterm labor, past preterm delivery, infection, carrying multiple fetuses, tobacco use, substance abuse, smoking, stress, high blood pressure, preeclampsia, diabetes, a blood clotting disorder, high weight, low weight, age under 20, age over 35, lack of prenatal medical care, pregnancy by in vitro fertilization, second pregnancy within 12 months, pregnancy following a most recent prior pregnancy by more than 59 months, shortened cervix, polyhydramnios, and/or carrying a fetus with a fetal birth defect. In various embodiments of methods of the present disclosure, the treatment reduces the likelihood of preterm labor as compared to a reference population. [0009] In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions for a period of at least 6 hours. In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions for a period of at least 24 hours. In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions for a period of at least 48 hours. In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions for a period of at least 72 hours. In various embodiments of methods of the present disclosure, the treatment reduces the strength, frequency, or duration of contractions for a period of at least 96 hours.

[0010] In various embodiments of methods of the present disclosure, the treatment delays labor for a period of at least 6 hours as compared to a reference. In various embodiments of methods of the present disclosure, the treatment delays labor for a period of at least 24 hours as compared to a reference. In various embodiments of methods of the present disclosure, the treatment delays labor for a period of at least 48 hours as compared to a reference. In various embodiments of methods of the present disclosure, the treatment delays labor for a period of at least 72 hours as compared to a reference. In various embodiments of methods of the present disclosure, the treatment delays labor for a period of at least 96 hours as compared to a reference.

[0011] In various embodiments of methods of the present disclosure, the treatment includes a single dose of the contraction-regulatory compound.

[0012] In at least one aspect of the present disclosure, the present disclosure provides a composition including a contraction-reducing compound, where the contraction- reducing compound is selected from: (a) niclosamide or a niclosamide analog; (b) a compound selected from dihydroouabain, piperlongumine, stevioside, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, lanatoside C, proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159; and/or (c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6. In various embodiments, the contraction-reducing compound is niclosamide. In various

embodiments, the contraction-reducing compound is a niclosamide analog according to Formula I. In various embodiments, the contraction-reducing compound is a niclosamide analog according to any one of Formulas I-a, I-b, I-c, I-d, I-e, I-f, or I-g. In various embodiments, the contraction-reducing compound is a niclosamide analog according to any one of Formulas 1-1, 1- 2, 1-3, 1-4, 1-5, 1-6 , 1-7, 1-8, 1-9, or 1-10. In various embodiments, the contraction-reducing compound is a niclosamide analog according to Formula II. In various embodiments, the contraction-reducing compound is selected from piperlongumine, JW74, U-73343, ONO-RS- 082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159. In various embodiments, the contraction-reducing compound is a cardiac glycoside according to the cardiac glycoside structure of FIG. 6. In various embodiments, the contraction-reducing compound is selected from dihydroouabain, stevioside, lanatoside C, and proscillaridin A. In various embodiments, the composition is for treating preterm labor in a subject in need thereof or for reducing contractions in a subject in need thereof.

DEFINITIONS

[0013] As used herein, the following definitions shall apply unless otherwise indicated.

For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75^th Ed. Additionally, general principles of organic chemistry are described in“Organic Chemistry”, Thomas Sorrell, University Science Books, Sausalito: 1999, and“March’s Advanced Organic Chemistry”, 5^th Ed., Ed.: Smith, M.B. and March, T, John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.

[0014] About: As used herein, term“about”, when used in reference to a value, refers to a value that is similar, in context to the referenced value. In general, those skilled in the art, familiar with the context, will appreciate the relevant degree of variance encompassed by “about” in that context. For example, in some embodiments, the term“about” may encompass a range of values that within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or less of the referenced value.

[0015] Administration: As used herein, the term“administration” typically refers to administration of a composition to a subject or system to achieve delivery of an agent that is, or is included in, the composition. [0016] Agent. As used herein, the term“agent” may refer to any chemical entity, including without limitation any of one or more of an atom, molecule, compound, amino acid, polypeptide, nucleotide, nucleic acid, protein, protein complex, liquid, solution, saccharide, polysaccharide, lipid, or combination or complex thereof.

[0017] Analog: As used herein, the term“analog” refers to a substance that shares one or more particular structural features, elements, components, or moieties with a reference substance, including without limitation compounds and/or formulas expressly identified herein as analog compounds and/or formulas. Typically, an“analog” shows significant structural similarity with the reference substance, for example sharing a core or consensus structure, but also differs in certain discrete ways. In some embodiments, an analog is a substance that can be generated from the reference substance, e.g., by chemical manipulation of the reference substance. In some embodiments, an analog is a substance that can be generated through performance of a synthetic process substantially similar to (e.g., sharing a plurality of steps with) one that generates the reference substance. In some embodiments, an analog is or can be generated through performance of a synthetic process different from that used to generate the reference substance.

[0018] Between or Front: As used herein, the term“between” refers to content that falls between indicated upper and lower, or first and second, boundaries, inclusive of the boundaries. Similarly, the term“from”, when used in the context of a range of values, indicates that the range includes content that falls between indicated upper and lower, or first and second, boundaries, inclusive of the boundaries.

[0019] Dosage form or unit dosage form: Those skilled in the art will appreciate that the term“dosage form” may be used to refer to a physically discrete unit of an agent (e.g., a therapeutic or diagnostic agent) for administration to a subject. Typically, each such unit contains a predetermined quantity of agent. In some embodiments, such quantity is a unit dosage amount (or a whole fraction thereof) appropriate for administration in accordance with a dosing regimen that has been determined to correlate with a desired or beneficial outcome when administered to a relevant population (i.e., with a therapeutic dosing regimen). Those of ordinary skill in the art appreciate that the total or free amount of a therapeutic composition or agent administered to a particular subject is determined by one or more attending physicians and may involve administration of multiple dosage forms.

[0020] “Improve”“increase”“inhibit” or“reduce”·. As used herein, the terms

“improve”,“increase”,“inhibit”, and“reduce”, and grammatical equivalents thereof, indicate qualitative or quantitative difference from a reference. Those of skill in the art will appreciate that any reference to the terms“improve”,“increase”,“inhibit”, and“reduce”, and grammatical equivalents thereof, includes without limitation statistically significant difference(s) in a relevant measure or value. Statistical significance is well understood in the art, and can characterizes differences that have a p value of a certain value or range, e.g., <0.05, according to any of one or more of a variety of statistical analyses well-known to those of skill in the art, including without limitation a t-test, ANOVA, regression analysis, and other statistical analyses, as may be applied in appropriate circumstances by those of skill in the art.

[0021] Pharmaceutically acceptable: As used herein, the term“pharmaceutically acceptable,” as applied to one or more, or all, component(s) for formulation of a composition as disclosed herein, means that each component must be compatible with the other ingredients of the composition and not deleterious to the recipient thereof.

[0022] Pharmaceutically acceptable carrier: As used herein, the term“pharmaceutically acceptable carrier” refers to a pharmaceutically-acceptable material, composition, or vehicle, such as a liquid or solid filler, diluent, excipient, or solvent encapsulating material, that facilitates formulation of an agent (e.g., a pharmaceutical agent), modifies bioavailability of an agent, or facilitates transport of an agent from one organ or portion of a subject to another. Some examples of materials which can serve as pharmaceutically-acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer’s solution; ethyl alcohol; pH buffered solutions; polyesters, polycarbonates and/or polyanhydrides; and other non-toxic compatible substances employed in pharmaceutical formulations.

[0023] Pharmaceutical composition·. As used herein, the term“pharmaceutical composition” refers to a composition in which a therapeutic agent is formulated together with one or more pharmaceutically acceptable carriers.

[0024] Reference: As used herein,“reference” refers to a standard or control relative to which a comparison is performed. For example, in some embodiments, an agent, sample, sequence, subject, animal, or individual, or population thereof, or a measure or characteristic representative thereof, is compared with a reference, an agent, sample, sequence, subject, animal, or individual, or population thereof, or a measure or characteristic representative thereof. In some embodiments, a reference is a measured value. In some embodiments, a reference is an established standard or expected value. In some embodiments, a reference is a historical reference. A reference can be quantitative of qualitative. Typically, as would be understood by those of skill in the art, a reference and the value to which it is compared represents measure under comparable conditions. Those of skill in the art will appreciate when sufficient similarities are present to justify reliance on and/or comparison. In some embodiments, an appropriate reference may be an agent, sample, sequence, subject, animal, or individual, or population thereof, under conditions those of skill in the art will recognize as comparable, e.g., for the purpose of assessing one or more particular variables (e.g., presence or absence of an agent or condition), or a measure or characteristic representative thereof.

[0025] Subject: As used herein, the term“subject” refers to an organism, typically a mammal (e.g., a human or non-human mammal). In some embodiments, a subject is suffering from a disease, disorder or condition. In some embodiments, a subject is susceptible to a disease, disorder, or condition. In some embodiments, a subject displays one or more symptoms or characteristics of a disease, disorder or condition. In some embodiments, a subject is not suffering from a disease, disorder or condition. In some embodiments, a subject does not display any symptom or characteristic of a disease, disorder, or condition. In some embodiments, a subject has one or more features characteristic of susceptibility to or risk of a disease, disorder, or condition. In some embodiments, a subject is a subject that has been tested for a disease, disorder, or condition, and/or to whom therapy has been administered. In some instances, a human subject can be interchangeably referred to as a“patient” or“individual.”

[0026] Therapeutic agent: As used herein, the term“therapeutic agent” refers to any agent that elicits a desired pharmacological effect when administered to a subject. In some embodiments, an agent is considered to be a therapeutic agent if it demonstrates a statistically significant effect across an appropriate population. In some embodiments, the appropriate population can be a population of model organisms or a human population. In some

embodiments, an appropriate population can be defined by various criteria, such as a certain age group, gender, genetic background, preexisting clinical conditions, etc. In some embodiments, a therapeutic agent is a substance that can be used for treatment of a disease, disorder, or condition. In some embodiments, a therapeutic agent is an agent that has been or is required to be approved by a government agency before it can be marketed for administration to humans. In some embodiments, a therapeutic agent is an agent for which a medical prescription is required for administration to humans.

[0027] Therapeutically effective amount: As used herein,“therapeutically effective amount” refers to an amount that produces the desired effect for which it is administered. In some embodiments, the term refers to an amount that is sufficient, when administered to a population suffering from or susceptible to a disease, disorder, and/or condition in accordance with a therapeutic dosing regimen, to treat the disease, disorder, and/or condition. In some embodiments, a therapeutically effective amount is one that reduces the incidence and/or severity of, and/or delays onset of, one or more symptoms of the disease, disorder, and/or condition. Those of ordinary skill in the art will appreciate that a therapeutically effective amount does not necessarily achieve successful treatment in every particular treated individual. Rather, a therapeutically effective amount may be that amount that provides a particular desired pharmacological response in a significant number of subjects when administered to patients in need of such treatment. In some embodiments, reference to a therapeutically effective amount may be a reference to an amount as measured in one or more specific tissues (e.g., a tissue affected by the disease, disorder or condition) or fluids (e.g., blood, saliva, serum, sweat, tears, urine, etc.). Those of ordinary skill in the art will appreciate that, in some embodiments, a therapeutically effective amount of a particular agent or therapy may be formulated and/or administered in a single dose. In some embodiments, a therapeutically effective agent may be formulated and/or administered in a plurality of doses, for example, as part of a dosing regimen.

[0028] Treatment. As used herein, the term“treatment” (also“treat” or“treating”) refers to administration of a therapy that partially or completely alleviates, ameliorates, relieves, inhibits, delays onset of, reduces severity of, and/or reduces incidence of one or more symptoms, features, and/or causes of a particular disease, disorder, or condition, or is administered for the purpose of achieving any such result. In some embodiments, such treatment can be of a subject who does not exhibit signs of the relevant disease, disorder, or condition and/or of a subject who exhibits only early signs of the disease, disorder, or condition. Alternatively or additionally, such treatment can be of a subject who exhibits one or more established signs of the relevant disease, disorder and/or condition. In some embodiments, treatment can be of a subject who has been diagnosed as suffering from the relevant disease, disorder, and/or condition. In some embodiments, treatment can be of a subject known to have one or more susceptibility factors that are statistically correlated with increased risk of development of the relevant disease, disorder, or condition.

[0029] Aliphatic or aliphatic group: As used herein, the term“aliphatic” or“aliphatic group” means a straight-chain (i.e., unbranched) or branched, substituted or unsubstituted hydrocarbon chain that is completely saturated or that contains one or more units of unsaturation, or a monocyclic hydrocarbon or bicyclic hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic (also referred to herein as “carbocycle,”“carbocyclic”,“cycloaliphatic” or“cycloalkyl”), that has a single point of attachment to the rest of the molecule. Unless otherwise specified, aliphatic groups contain 1-6 aliphatic carbon atoms. In some embodiments, aliphatic groups contain 1-5 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-4 aliphatic carbon atoms. In still other embodiments, aliphatic groups contain 1-3 aliphatic carbon atoms, and in yet other

embodiments, aliphatic groups contain 1-2 aliphatic carbon atoms. In some embodiments, “carbocyclic” (or“cycloaliphatic” or“carbocycle” or“cycloalkyl”) refers to a monocyclic C3-C8 hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule. Suitable aliphatic groups include, but are not limited to, linear or branched, substituted or unsubstituted alkyl, alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

[0030] Lower alkyl: As used herein, the term“lower alkyl” refers to a Ci-4 straight or branched alkyl group. Exemplary lower alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl.

[0031] Halogen: As used herein, the term“halogen” means F, Cl, Br, or I.

[0032] Heteroaryl and heteroar-: As used herein, the terms“heteroaryl” and“heteroar-

,” used alone or as part of a larger moiety, e.g.,“heteroaralkyl,” or“heteroaralkoxy,” refer to groups having 5 to 10 ring atoms, preferably 5, 6, or 9 ring atoms; having 6, 10, or 14□ electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. The term“heteroatom” refers to nitrogen, oxygen, or sulfur, and includes any oxidized form of nitrogen or sulfur, and any quatemized form of a basic nitrogen. Exemplary heteroaryl groups include thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, and pteridinyl. The terms “heteroaryl” and“heteroar-”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Examplary groups include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, AH quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl,

tetrahydroisoquinolinyl, and pyrido[2,3-b]-l,4-oxazin-3(4H)-one. A heteroaryl group may be mono- or bicyclic. The term“heteroaryl” may be used interchangeably with the terms “heteroaryl ring,”“heteroaryl group,” or“heteroaromatic,” any of which terms include rings that are optionally substituted. The term“heteroaralkyl” refers to an alkyl group substituted by a heteroaryl, wherein the alkyl and heteroaryl portions independently are optionally substituted.

[0033] Optionally substituted: As described herein, compounds of the disclosure may contain“optionally substituted” moieties. In general, the term“substituted,” whether preceded by the term“optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. “Substituted” applies to one or more hydrogens that are either explicit or implicit from the structure (e.g.,

refers to at least

; and

, _, ). Unless otherwise indicated, an“optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this disclosure are preferably those that result in the formation of stable or chemically feasible compounds. The term“stable,” as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein.

[0034] Suitable monovalent substituents on a substitutable carbon atom of an“optionally substituted” group are independently halogen; - (CH2)_0-4R°; - (CH2)_0-4OR^°; -O (CH2)_0-4R°, -O- (CH2)_0-4C(O)OR°; - (CH2)_0-4CH(OR°)2; - (CH2)_0-4SR°; - (CH2)_0-4Ph, which may be substituted with R°; - (CH2)_0-4O(CH2)o-iPh which may be substituted with R°; -CH=CHPh, which may be substituted with R°; -(CH2)_0-4O (CH2)_0-1- pyridyl which may be substituted with R°; -NO₂; -CN; -N₃; - (CH2)_0-4N(R°)2; - (CH₂)_0-4N(R^°)C(O)R°; -N(R°)C(S)R°; - (CH2)_0-4N(R^°)C(O)NR°₂; -N(R°)C(S)NR°₂; - (CH2)_0-4N(R^°)C(O)OR°; -N(R°)N(R°)C(O)R°; -N(R^°)N(R^°)C(O)NR^° ₂; -N(R°)N(R°)C(O)OR°; - (CH2)_0-4C(O)R°; -C(S)R°; - (CH2)_0-4C(O)OR°; - (CH2)_0-4C(O)SR°; - (CH2)_0-4C(O)OSiR°3; - (CH2)_0-4OC(O)R°; -OC(O) (CH2)_0-4SR°; - (CH2)_0-4SC(O)R°;

-(CH2)_0-4C(O)NR°2; -C(S)NR°₂; -C(S)SR°; -SC(S)SR°, -(CH2)_0-4OC(O)NR°₂;

-C(O)N(OR°)R°; -C(O)C(O)R°; -C(O)CH₂C(O)R°; -C(NOR°)R°; - (CH₂)_0-4SSR°;

- (CH₂)_0-4 S(O)₂R° ; - (CH₂)_0-4 S(O)₂OR° ; - (CH₂)_0-4OS(O)₂R°; -S(O)₂NR^° ₂; - (CH₂)_0-4S(O)R°; -N(R°)S(O)₂NR°2; -N(R°)S(O)₂R°; -N(OR°)R°; -C(NH)NR°₂; -P(O)₂R°; -P(O)R°₂;

-OP(O)R°₂; -OP(O)(OR°)₂; Si R°₃ ; -(C_{1 -4} straight or branched alkylene)O-N(R°)2; or -(C_1-4 straight or branched alkylene)C(O)0-N(R°)2, wherein each R° may be substituted as defined below and is independently hydrogen, Ci-₆ aliphatic, -CfhPh, -0(CH2)o-iPh, -CH2-(5-6 membered heteroaryl ring), or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or,

notwithstanding the definition above, two independent occurrences of R°, taken together with their intervening atom(s), form a 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below.

[0035] Suitable monovalent substituents on R° (or the ring formed by taking two independent occurrences of R° together with their intervening atoms), are independently halogen, -(CH₂)O-2R·, -(haloR*), -(CH₂)o-20H, -(CH₂)O-20R·, -(CH₂)O-2CH(OR*)2;

-0(haloR·), -CN, -Ns, -(CH₂)O-₂C(O)R·, -(CH₂)O-₂C(O)OH, -(CH₂)O-₂C(O)OR·,

-(CH₂)O-2SR·, -(CH₂)O-₂SH, -(CH₂)O-2NH₂, -(CH₂)O-2NHR·, -(CH₂)O-2NR*2, -NO2, -SiR'v -OSiR*3, -C(O)SR*—(Ci— 4 straight or branched alkylene)C(O)OR*, or -SSR* wherein each R* is unsubstituted or where preceded by“halo” is substituted only with one or more halogens, and is independently selected from C1-4 aliphatic, -CfhPh, -0(CH2)o-iPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of R° include =0 and =S.

[0036] Suitable divalent substituents on a saturated carbon atom of an“optionally substituted” group include the following: =0 (“oxo”), =S, =NNR^*2, =NNHC(O)R^*,

=NNHC(O)OR^*, =NNHS(O)₂R^*, =NR^*, =NOR^*, -0(C(R^* ₂))2-30-, or -S(C(R^* ₂))_2-3S-, wherein each independent occurrence of R^* is selected from hydrogen, Ci-₆ aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an“optionally substituted” group include: -0(CR%)2-₃0-, wherein each independent occurrence of R^* is selected from hydrogen, Ci-₆ aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4

heteroatoms independently selected from nitrogen, oxygen, or sulfur. [0037] Suitable substituents on the aliphatic group of R^* include halogen, R*, -(haloR*),

-OH, -OR*, -0(haloR*), -CN, -C(O)0H, -C(O)0R*, -NH₂, NHR*, -NR*₂, or -N0₂, wherein each R* is unsubstituted or where preceded by“halo” is substituted only with one or more halogens, and is independently Ci-4 aliphatic, -CHzPh, -0(CH₂)o-iPh, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

[0038] Suitable substituents on a substitutable nitrogen of an“optionally substituted” group include -R^†, -NR^† ₂, -C(O)R^†, -C(O)OR^†, -C(O)C(O)R^†, -C(O)CH₂C(O)R^†, -S(O)₂R^†, -S(O)₂NR^† ₂, -C(S)NR^† ₂, -C(NH)NR^† ₂, or -N(R^†)S(O)₂R^†; wherein each R^† is independently hydrogen, Ci-₆ aliphatic which may be substituted as defined below, unsubstituted -OPh, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4

heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^†, taken together with their intervening atom(s) form an unsubstituted 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

[0039] Suitable substituents on the aliphatic group of R^† are independently halogen,

-R·, -(haloR*), -OH, -OR*, -O(haloR'), -CN, -C(O)OH, -C(O)OR*, -NH₂, -NHR*, -NR*_2, or -N0₂, wherein each R* is unsubstituted or where preceded by“halo” is substituted only with one or more halogens, and is independently Ci-4 aliphatic, -CHzPh, -0(CH₂)o-iPh, or a 5-6- membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

[0040] Pharmaceutically acceptable salt: As used herein, the term "pharmaceutically acceptable salt" refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge et ah, describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66, 1-19, incorporated herein by reference. Pharmaceutically acceptable salts of the compounds of this disclosure include those derived from suitable inorganic and organic acids and bases.

Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecyl sulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemi sulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like.

[0041] Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N⁺(Ci^alkyl)4 salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, loweralkyl sulfonate and aryl sulfonate.

[0042] Stable: As used herein, the term“stable” refers to compounds which possess stability sufficient to allow manufacture and which maintains the integrity of the compound for a sufficient period of time to be useful for the purposes detailed herein (e.g., therapeutic or prophylactic administration to a subject).

[0043] Combinations of substituents and variables envisioned by this disclosure are only those that result in the formation of stable compounds.

[0044] Unless otherwise stated, structures depicted herein are also meant to include all isomeric (e.g., enantiomeric, diastereomeric, and geometric (or conformational)) forms of the structure; for example, the R and S configurations for each asymmetric center, Z and E double bond isomers, and Z and E conformational isomers. Therefore, single stereochemical isomers as well as enantiomeric, diastereomeric, and geometric (or conformational) mixtures of the present compounds are within the scope of the disclosure. Unless otherwise stated, all tautomeric forms of the compounds of the disclosure are within the scope of the disclosure.

[0045] The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups. The recitation of an embodiment for a variable herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.

BRIEF DESCRIPTION OF THE DRAWING

[0046] FIG. 1 includes panels A, B, and C. Panel A is a representation of a contractility assay. Panel B is a representation of analysis of a contractility assay. Panel C is a work-flow for a contractility assay.

[0047] FIG. 2 includes panels A and B. Panel A is a graph of results of a contractility assay. Panel B is a graph of results of a contractility assay.

[0048] FIG. 3 is a graph showing results of a contractility assay.

[0049] FIG. 4 is a set of chemical structures identified as chemical structure A to chemical structure M. Panel A provides the structure of GR 127935 hydrochloride hydrate.

Panel B. provides the structure of Piperlongumine. Panel C. provides the structure of NAN- 190 hydrobromide. Panel D provides the structure of MRS 2159. Panel E provides the structure of JW74. Panel F provides the structure of U-73343. Panel G provides the structure of ONO-RS- 082. Panel H provides the structure of THAPSIGARGIN. Panel I provides the structure of PD173952. Panel J provides the structure of Amisulpride. Panel K provides the structure of AC-55649. Panel L provides the structure of Gliclazide. Panel M provides the structure of Tetracaine hydrochloride.

[0050] FIG. 5 includes panels A-D. Panel A provides the chemical structure of niclosamide. Panel B provides the general chemical structure for certain niclosamide analogs with significant chemical similarity to niclosamide but with modified properties such as solubility, bioavailability, or efficacy. Panels C(Ri) and D (R2 and R3) provide possible R groups that could be added or used as replacement at the indicated positions of niclosamide.

[0051] FIG. 6 includes panels A-E. Panel A provides the general structure of cardiac glycosides consisting of a steroid molecule attached to a sugar and an R group. The steroid nucleus consists of four fused rings to which other functional groups may be attached. Panel B provides the general structure for Dihydroouabain. Panel C provides the general structure for Stevioside. Panel D provides the general structure for Lanatoside C. Panel E provides the general structure for Proscillaridin A.

[0052] FIG. 7 is a pair of graphs showing contraction of uterine smooth muscle cells treated with nifedipine or ritodrine after 30 minutes or 5 hours as a percentage of the contraction of cells treated with negative (vehicle) control (0.5% DMSO).

[0053] FIG. 8 is a set of four graphs showing the contraction of uterine smooth muscle cells at various concentrations and durations for niclosamide, PD173952, tetracaine, and JW74, as a percentage of the of the contraction of cells treated with negative (vehicle) control (0.5% DMSO).

DETAILED DESCRIPTION

[0054] The present disclosure provides contraction-regulatory compounds useful, e.g., in the treatment of preterm labor and/or reducing the strength, frequency, or duration of contractions.

Contraction-Regulatory compounds

[0055] In some embodiments, a contraction-regulatory compound of the present disclosure is a compound according to Formula I. In some embodiments, a contraction- regulatory compound of the present disclosure is niclosamide or a niclosamide analog. The formula of niclosamide is provided herein in FIG. 1A and in Formula 1-1. Niclosamide analogs include, without limitation, niclosamide analogs as described in FIG. 5B, niclosamide analogs of Formula 1, niclosamide analogs according to any one of Formulas I-a to 1-g, niclosamide analogs according to any one of Formulas 1-1 to 1-10, and niclosamide analogs according to Formula II. Those of skill in In certain embodiments, a contraction-regulatory compound of the present disclosure is a compound according to Formula I-a, I-b, I-c, I-d, I-e, I-f, or I-g. In certain embodiments, a contraction-regulatory compound of the present disclosure is a compound according to Formula 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, or 1-10. In some embodiments, a contraction-regulatory compound of the present disclosure is a compound according to Formula II. In some embodiments, a contraction-regulatory compound of the present disclosure is a compound listed in FIG. 2 and/or illustrated in FIG. 4, FIG. 5, or FIG. 6, including any of Dihydroouabain, Piperlongumine, Niclosamide, Stevioside, JW74, U-73343, ONO-RS-082, Thapsigargin, PD173952, Amisulpride, AC-55649, Gliclazide, Tetracaine hydrochloride, Lanatoside C, Proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and MRS 2159. In some embodiments, a contraction-regulatory compound of the present disclosure is a compound illustrated in FIG. 4, including any of Piperlongumine, JW74, U-73343, ONO- RS-082, Thapsigargin, PD173952, Amisulpride, AC-55649, Gliclazide, Tetracaine

hydrochloride, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and MRS 2159. In some embodiments, a contraction-regulatory compound of the present disclosure is a compound illustrated in FIG. 6, including any of a cardiac glycoside according to the general cardiac glycoside structure of FIG. 6, Dihydroouabain, Stevioside, Lanatoside C, and Proscillaridin A.

[0056] In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction Z-score of less than -1, less than -2, less than -3, or less than -4 at a time about 30 minutes after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No.

PCT/US 15/23136 (published as WO/2015/149002; see also, e.g., U.S. Pat. Nos. 10,082,497 and 10,473,644) (each of which is incorporated herein by reference with respect to contractility assays and in its entirety) at a concentration of 1 mM, 5 mM, or 10 pM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction Z-score of less than -1, less than -2, less than -3, or less than -4 at a time about 1 hour after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration of 1 pM, 5 pM, or 10 pM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction Z-score of less than -1, less than -2, less than -3, or less than -4 at a time about 6 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International

Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration of 1 pM,

5 pM, or 10 pM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction Z-score of less than -1, less than -2, less than -3, or less than -4 at a time about 12 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration of 1 mM, 5 mM, or 10 pM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction Z- score that is less than -1, less than -2, less than -3, or less than -4 at a time about 24 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No.

PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as

WO/2015/149002) at a concentration of 1 pM, 5 pM, or 10 pM.

[0057] In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction z-score that is in a range having an upper bound of -1, -2, -3, or -5 and a lower bound of -2, -3, -4, -5, or -6 at a time about 30 minutes after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) (which is incorporated herein by reference with respect to contractility assays and in its entirety) at a concentration that is within a range having a lower bound of 1 pM, 2 pM, 3 pM, 4 pM, 5 pM, 6 pM, 7 pM, 8 pM, 9 pM, or 10 pM and an upper bound of 5 pM, 6 pM, 7 pM, 8 pM, 9 pM, 10 pM, 11 pM, 12 pM, 13 pM, 14 pM, 15 pM, 16 pM, 17 pM, 18 pM, 19 pM, or 20 pM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction z- score that is in a range having a lower bound of -1, -2, -3, or -5 and an upper bound of -2, -3, -4, - 5, or -6 at a time about 1 hour after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration that is within a range having a lower bound of 1 pM, 2 pM, 3 pM, 4 pM, 5 pM, 6 pM, 7 pM, 8 pM, 9 pM, orlO pM and an upper bound of 5 pM, 6 pM, 7 pM, 8 pM, 9 pM, 10 pM, 11 pM, 12 pM, 13 pM, 14 pM, 15 pM, 16 pM, 17 pM, 18 pM, 19 pM, or 20 pM. In some embodiments, a contraction- regulatory compound of the present disclosure has a contraction z-score that is in a range having a lower bound of -1, -2, -3, or -5 and an upper bound of -2, -3, -4, -5, or -6 at a time about 6 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration that is within a range having a lower bound of 1 mIUΊ, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, or 10 mM and an upper bound of 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, 10 mM, 11 mM, 12 mM, 13 mM, 14 mM, 15 mM, 16 mM, 17 mM, 18 mM, 19 mM, or 20 mM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction z-score that is in a range having a lower bound of -1, -2, -3, or -5 and an upper bound of -2, -3, -4, -5, or -6 at a time about 12 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a

concentration that is within a range having a lower bound of 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, or 10 mM and an upper bound of 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, 10 mM, 11 mM, 12 mM, 13 mM, 14 mM, 15 mM, 16 mM, 17 mM, 18 mM, 19 mM, or 20 mM. In some embodiments, a contraction-regulatory compound of the present disclosure has a contraction z- score that is in a range having a lower bound of -1, -2, -3, or -5 and an upper bound of -2, -3, -4, - 5, or -6 at a time about 24 hours after administration of the compound to uterine cells in a contractility assay as disclosed herein (e.g., in Example 1) and/or in a contractility assay disclosed in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002) at a concentration that is within a range having a lower bound of 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, orlO mM and an upper bound of 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, 10 mM, 11 mM, 12 mM, 13 mM, 14 mM, 15 mM, 16 mM, 17 mM, 18 mM, 19 mM, or 20 mM.

[0058] According to one aspect, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I:

or a pharmaceutically acceptable salt thereof;

wherein,

each R⁴, R⁵, R⁶, R⁷, and R⁸ is independently selected from the group consisting of hydrogen, - NO2, halogen, -OR^x, or -COOR^x, or an optionally substituted Ci-6 aliphatic group;

each R^x is independently selected from the group consisting of hydrogen or optionally

substituted Ci-6 aliphatic; and

each R⁹, R¹⁰, R¹¹, R¹², and R¹³ is independently selected from the group consisting of hydrogen, Ci-6 aliphatic, -NO2, halogen, -OR^x, -COOR^x, an optionally substituted Ci-6 aliphatic group, or an optionally substituted ring selected from phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur; or

two of R⁹, R¹⁰, R¹¹, R¹², and R¹³ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur.

[0059] In some embodiments, R⁴ is hydrogen. In some embodiments, R⁴ is -NO2, halogen, -OR^x, or -COOR^x. In some embodiments, R⁴ is -NO2. In some embodiments, R⁴ is halogen. In some embodiments, R⁴ is fluorine. In some embodiments, R⁴ is chlorine. In some embodiments, R⁴ is bromine. In some embodiments, R⁴ is iodine. In some embodiments, R⁴ is - OR^x. In some embodiments, R⁴ is -OH. In some embodiments, R⁴ is -OMe. In some embodiments, R⁴ is -COOR^x. In some embodiments, R⁴ is -COOH. In some embodiments, R⁴ is -COOMe. In some embodiments, R⁴ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R⁴ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁴ is Ci-6 alkyl. In some embodiments, R⁴ is C1-3 alkyl. In some embodiments, R⁴ is methyl. In some embodiments, R⁴ is ethyl. In some embodiments, R⁴ is propyl. [0060] In some embodiments, R⁵ is hydrogen. In some embodiments, R⁵ is -NCte, halogen, -OR^x, or -COOR^x. In some embodiments, R⁵ is -NC . In some embodiments, R⁵ is halogen. In some embodiments, R⁵ is fluorine. In some embodiments, R⁵ is chlorine. In some embodiments, R⁵ is bromine. In some embodiments, R⁵ is iodine. In some embodiments, R⁵ is - OR^x. In some embodiments, R⁵ is -OH. In some embodiments, R⁵ is -OMe. In some embodiments, R⁵ is -COOR^x. In some embodiments, R⁵ is -COOH. In some embodiments, R⁵ is -COOMe. In some embodiments, R⁵ is an optionally substituted Ci-₆ aliphatic group. In some embodiments, R⁵ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁵ is Ci-₆ alkyl. In some embodiments, R⁵ is C1-3 alkyl. In some embodiments, R⁵ is methyl. In some embodiments, R⁵ is ethyl. In some embodiments, R⁵ is propyl.

[0061] In some embodiments, R⁶ is hydrogen. In some embodiments, R⁶ is -NCte, halogen, -OR^x, or -COOR^x. In some embodiments, R⁶ is -NCte. In some embodiments, R⁶ is halogen. In some embodiments, R⁶ is fluorine. In some embodiments, R⁶ is chlorine. In some embodiments, R⁶ is bromine. In some embodiments, R⁶ is iodine. In some embodiments, R⁶ is - OR^x. In some embodiments, R⁶ is -OH. In some embodiments, R⁶ is -OMe. In some embodiments, R⁶ is -COOR^x. In some embodiments, R⁶ is -COOH. In some embodiments, R⁶ is -COOMe. In some embodiments, R⁶ is an optionally substituted Ci-₆ aliphatic group. In some embodiments, R⁶ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁶ is Ci-₆ alkyl. In some embodiments, R⁶ is C1-3 alkyl. In some embodiments, R⁶ is methyl. In some embodiments, R⁶ is ethyl. In some embodiments, R⁶ is propyl.

[0062] In some embodiments, R⁷ is hydrogen. In some embodiments, R⁷ is -NCte, halogen, -OR^x, or -COOR^x. In some embodiments, R⁷ is -NCte. In some embodiments, R⁷ is halogen. In some embodiments, R⁷ is fluorine. In some embodiments, R⁷ is chlorine. In some embodiments, R⁷ is bromine. In some embodiments, R⁷ is iodine. In some embodiments, R⁷ is - OR^x. In some embodiments, R⁷ is -OH. In some embodiments, R⁷ is -OMe. In some embodiments, R⁷ is -COOR^x. In some embodiments, R⁷ is -COOH. In some embodiments, R⁷ is -COOMe. In some embodiments, R⁷ is an optionally substituted Ci-₆ aliphatic group. In some embodiments, R⁷ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁷ is Ci-₆ alkyl. In some embodiments, R⁷ is C1-3 alkyl. In some embodiments, R⁷ is methyl. In some embodiments, R⁷ is ethyl. In some embodiments, R⁷ is propyl. [0063] In some embodiments, R⁸ is hydrogen. In some embodiments, R⁸ is -NCte, halogen, -OR^x, or -COOR^x. In some embodiments, R⁸ is -NC . In some embodiments, R⁸ is halogen. In some embodiments, R⁸ is fluorine. In some embodiments, R⁸ is chlorine. In some embodiments, R⁸ is bromine. In some embodiments, R⁸ is iodine. In some embodiments, R⁸ is - OR^x. In some embodiments, R⁸ is -OH. In some embodiments, R⁸ is -OMe. In some embodiments, R⁸ is -COOR^x. In some embodiments, R⁸ is -COOH. In some embodiments, R⁸ is -COOMe. In some embodiments, R⁸ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R⁸ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁸ is Ci-6 alkyl. In some embodiments, R⁸ is C1-3 alkyl. In some embodiments, R⁸ is methyl. In some embodiments, R⁸ is ethyl. In some embodiments, R⁸ is propyl.

[0064] In some embodiments, R⁴, R⁵, R⁷, and R⁸ are hydrogen. In some embodiments,

R⁴, R⁵, R⁷, and R⁸ are hydrogen, and R⁶ is -NCh. In some embodiments, R⁴, R⁵, R⁷, and R⁸ are hydrogen, and R⁶ is halogen. In some embodiments, R⁴, R⁵, R⁷, and R⁸ are hydrogen, and R⁶ is chlorine. In some embodiments, R⁴, R⁵, R⁷, and R⁸ are hydrogen, and R⁶ is bromine.

[0065] In some embodiments, R⁵, R⁶, R⁷, and R⁸ are hydrogen. In some embodiments,

R⁵, R⁶, R⁷, and R⁸ are hydrogen, and R⁴ is halogen. In some embodiments, R⁵, R⁶, R⁷, and R⁸ are hydrogen, and R⁴ is chlorine.

[0066] In some embodiments, R⁵, R⁷, and R⁸ are hydrogen. In some embodiments, R⁵,

R⁷, and R⁸ are hydrogen, and R⁴ and R⁶ are independently selected from -NCh, halogen, and - OR^x. In some embodiments, R⁵, R⁷, and R⁸ are hydrogen, and R⁴ and R⁶ are independently selected from halogen. In some embodiments, R⁵, R⁷, and R⁸ are hydrogen, and R⁴ and R⁶ are chlorine. In some embodiments, R⁵, R⁷, and R⁸ are hydrogen, and R⁴ and R⁶ independently selected from -NCh and -OR^x. In some embodiments, R⁵, R⁷, and R⁸ are hydrogen, and R⁴ and R⁶ independently selected from -NCh and -OMe. In some embodiments, R⁵, R⁷, and R⁸ are hydrogen, R⁴ is -OMe, and R⁶ is -NO2.

[0067] In some embodiments, R⁴, R⁵, R⁶, R⁷, and R⁸ are hydrogen

[0068] In some embodiments, R^x is hydrogen. In some embodiments, R^x is optionally substituted Ci-6 aliphatic. In some embodiments, R^x is optionally substituted C1-4 aliphatic. In some embodiments, R^x is Ci-6 alkyl. In some embodiments, R^x is C1-3 alkyl. In some embodiments, R^x is methyl. In some embodiments, R^x is ethyl. In some embodiments, R^x is propyl.

[0069] In some embodiments, each R⁹, R¹⁰, R¹¹, R¹², and R¹³ is independently selected from the group consisting of hydrogen, -NCte, halogen, -OR^x, -COOR^x, an optionally substituted Ci-6 aliphatic group, or an optionally substituted ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl.

[0070] In some embodiments, R⁹ is hydrogen. In some embodiments, R⁹ is -NCte. In some embodiments, R⁹ is halogen. In some embodiments, R⁹ is fluorine. In some embodiments, R⁹ is chlorine. In some embodiments, R⁹ is bromine. In some embodiments, R⁹ is iodine. In some embodiments, R⁹ is -OR^x. In some embodiments, R⁹ is -OH. In some embodiments, R⁹ is -OMe. In some embodiments, R⁹ is -COOR^x. In some embodiments, R⁹ is -COOH. In some embodiments, R⁹ is -COOMe. In some embodiments, R⁹ is phenyl. In some embodiments, R⁹ is pyrrolyl. In some embodiments, R⁹ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R⁹ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R⁹ is Ci-6 alkyl. In some embodiments, R⁹ is Ci-3 alkyl. In some embodiments, R⁹ is methyl. In some embodiments, R⁹ is ethyl. In some embodiments, R⁹ is propyl.

[0071] In some embodiments, R¹⁰ is hydrogen. In some embodiments, R¹⁰ is -NCte. In some embodiments, R¹⁰ is halogen. In some embodiments, R¹⁰ is fluorine. In some

embodiments, R¹⁰ is chlorine. In some embodiments, R¹⁰ is bromine. In some embodiments, R¹⁰ is iodine. In some embodiments, R¹⁰ is -OR^x. In some embodiments, R¹⁰ is -OH. In some embodiments, R¹⁰ is -OMe. In some embodiments, R¹⁰ is -COOR^x. In some embodiments, R¹⁰ is -COOH. In some embodiments, R¹⁰ is -COOMe. In some embodiments, R¹⁰ is phenyl. In some embodiments, R¹⁰ is pyrrolyl. In some embodiments, R¹⁰ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R¹⁰ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R¹⁰ is Ci-6 alkyl. In some embodiments, R¹⁰ is C1-3 alkyl. In some embodiments, R¹⁰ is methyl. In some embodiments, R¹⁰ is ethyl. In some embodiments, R¹⁰ is propyl.

[0072] In some embodiments, R¹¹ is hydrogen. In some embodiments, R¹¹ is -NCte. In some embodiments, R¹¹ is halogen. In some embodiments, R¹¹ is fluorine. In some embodiments, R¹¹ is chlorine. In some embodiments, R¹¹ is bromine. In some embodiments, R¹¹ is iodine. In some embodiments, R¹¹ is -OR^x. In some embodiments, R¹¹ is -OH. In some embodiments, R¹¹ is -OMe. In some embodiments, R¹¹ is -COOR^x. In some embodiments, R¹¹ is -COOH. In some embodiments, R¹¹ is -COOMe. In some embodiments, R¹¹ is phenyl. In some embodiments, R¹¹ is pyrrolyl. In some embodiments, R¹¹ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R¹¹ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R¹¹ is Ci-6 alkyl. In some embodiments, R¹¹ is C1-3 alkyl. In some embodiments, R¹¹ is methyl. In some embodiments, R¹¹ is ethyl. In some embodiments, R⁴ is propyl.

[0073] In some embodiments, R¹² is hydrogen. In some embodiments, R¹² is -NO2. In some embodiments, R¹² is halogen. In some embodiments, R¹² is fluorine. In some

embodiments, R¹² is chlorine. In some embodiments, R¹² is bromine. In some embodiments, R¹² is iodine. In some embodiments, R¹² is -OR^x. In some embodiments, R¹² is -OH. In some embodiments, R¹² is -OMe. In some embodiments, R¹² is -COOR^x. In some embodiments, R¹² is -COOH. In some embodiments, R¹² is -COOMe. In some embodiments, R¹² is phenyl. In some embodiments, R¹² is pyrrolyl. In some embodiments, R¹² is an optionally substituted Ci-6 aliphatic group. In some embodiments, R¹² is an optionally substituted Ci-4 aliphatic group. In some embodiments, R¹² is Ci-6 alkyl. In some embodiments, R¹² is C1-3 alkyl. In some embodiments, R¹² is methyl. In some embodiments, R¹² is ethyl. In some embodiments, R¹² is propyl.

[0074] In some embodiments, R¹³ is hydrogen. In some embodiments, R¹³ is -NO2. In some embodiments, R¹³ is halogen. In some embodiments, R¹³ is fluorine. In some

embodiments, R¹³ is chlorine. In some embodiments, R¹³ is bromine. In some embodiments, R¹³ is iodine. In some embodiments, R¹³ is -OR^x. In some embodiments, R¹³ is -OH. In some embodiments, R¹³ is -OMe. In some embodiments, R¹³ is -COOR^x. In some embodiments, R¹³ is -COOH. In some embodiments, R¹³ is -COOMe. In some embodiments, R¹³ is phenyl. In some embodiments, R¹³ is pyrrolyl. In some embodiments, R¹³ is an optionally substituted Ci-6 aliphatic group. In some embodiments, R¹³ is an optionally substituted Ci-4 aliphatic group. In some embodiments, R¹³ is Ci-6 alkyl. In some embodiments, R¹³ is C1-3 alkyl. In some embodiments, R¹³ is methyl. In some embodiments, R¹³ is ethyl. In some embodiments, R¹³ is propyl.

[0075] In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form an optionally substituted phenyl or pyrrolyl ring. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form an optionally substituted phenyl ring. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form an optionally substituted pyrrolyl ring. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form a ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form a phenyl or pyrrolyl ring. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form a phenyl ring. In some embodiments, R⁹ and R¹⁰ are taken together with intervening atoms to form a pyrrolyl ring.

[0076] In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form an optionally substituted phenyl or pyrrolyl ring. In some

embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form an optionally substituted phenyl ring. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form an optionally substituted pyrrolyl ring. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form a ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form a phenyl or pyrrolyl ring. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form a phenyl ring. In some embodiments, R¹⁰ and R¹¹ are taken together with intervening atoms to form a pyrrolyl ring.

[0077] In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form an optionally substituted phenyl or pyrrolyl ring. In some

embodiments, R¹¹ and R¹² are taken together with intervening atoms to form an optionally substituted phenyl ring. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form an optionally substituted pyrrolyl ring. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form a ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form a phenyl or pyrrolyl ring. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form a phenyl ring. In some embodiments, R¹¹ and R¹² are taken together with intervening atoms to form a pyrrolyl ring.

[0078] In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl or a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from the group consisting of nitrogen, oxygen, and sulfur. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form an optionally substituted ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form an optionally substituted phenyl or pyrrolyl ring. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form an optionally substituted phenyl ring. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form an optionally substituted pyrrolyl ring. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form a ring selected from the group consisting of phenyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, furan, pyridinyl, pyrimidinyl, pyridazinyl, pyrimidinyl, and triazinyl. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form a phenyl or pyrrolyl ring. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form a phenyl ring. In some embodiments, R¹² and R¹³ are taken together with intervening atoms to form a pyrrolyl ring.

[0079] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-a:

I-a

or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹¹, and R¹² is as defined above and described in embodiments, classes, and subclasses above and herein singly or in combination.

[0080] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-b:

I-b or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹¹, and R¹² is as defined above and described in embodiments, classes, and subclasses above and herein singly or in combination.

[0081] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-c:

or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁶, R⁸, R⁹, R¹¹, and R¹² is as defined above and described in embodiments, classes, and subclasses above and herein singly or in combination.

[0082] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-d:

I-d

or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁶, and R⁸ is as defined above and described in embodiments, classes, and subclasses above and herein singly or in

combination.

[0083] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-e:

I-e

or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁶, and R⁸ is as defined above and described in embodiments, classes, and subclasses above and herein singly or in combination.

[0084] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-f:

I-f

[0085] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound of Formula I-g:

i-g

or a pharmaceutically acceptable salt thereof, wherein each R⁴, R⁶, and R⁸ is as defined above and described in embodiments, classes, and subclasses above and herein singly or in combination. [0086] In certain embodiments, the present disclosure provides a contraction-regulatory compound that is a compound selected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

[0087] According to one aspect, the present disclosure provides a contraction-regulatory compound that is a compound of Formula II:

[0088] In some embodiments, the present disclosure provides a contraction-regulatory compound that is a compound:

Preterm Labor

[0089] The uterus is unique among smooth muscular organs at least in that, during pregnancy, it undergoes profound, largely reversible, changes orchestrated at least in part by ovarian hormones. These changes facilitate uterine adaptation to the stretch induced by the growing fetus such that a state of myometrial contractile quiescence can be maintained. The uterus must achieve enormous expansion to accomodate the growing fetus, and to support the fetus through sustained muscle tone, without generating propagated contractions. This state of quiescence-the absence of coordinated contractions-is critical to the successful outcome of pregnancy, but remains poorly understood. A quiescent state usually is maintained until fetal development is sufficient for extrauterine life, at which point unknown mechanisms precipitate conversion to a highly contractile state. The delicate balance between maintenance of tone and resistance to propagated contractions continues to the end of gestation and the onset of labor, when the uterus becomes active and empties its contents through rhythmic, forceful, organized contractile waves. Contractions include, and can be defined by, a shortening of uterine muscles occurring at intervals in a subject, typically in connection with child birth (e.g., before and/or during labor and/or delivery). Throughout pregnancy, signaling mechanisms for myometrial contractility are altered-first to promote quiescence and then again to promote contractions. The mechanisms responsible for these changes are only partially understood.

[0090] Labor includes a series of uterine contractions (also referred to herein as contractions) that precede child birth. The beginning of labor is marked by repeated

contractions, which can be mild and/or irregular in early labor. The duration of labor varies among individuals, and can last minutes, hours, or days. Uterine contractions generally tend to become stronger and more regular as a typical labor progresses. Medical practitioners, including but not limited to obstetricians and gynecologists, are experienced in detecting and/or identifying labor, as well as tools and techniques for detecting and/or identifying labor. For example, various tools and techniques are available for the detection of contractions, including

tocodynometers, electronic fetal monitors, intrauterine pressure catheter (IUPC), electrical uterine myography (EUM), and electrohysterography. Additional tools and techniques that are also helpful in detecting labor can include testing for amniotic fluid, fetal fibronectin (fFN) and cervical length (CL) (e.g., measured by cervical exam or ultrasound).

[0091] In various embodiments, the strength and duration of a contraction is measured as the difference from baseline (when the uterus is relaxed) to the peak of contraction. In various embodiments, the strength of a contraction is measured in units, where one unit is the amount of pressure that raises a column of mercury one millimeter. In some embodiments, 20 to 40 units/minute on average, e.g., over a 10 minute period is sufficient for labor by vaginal delivery. In various embodiments, a reduces strength of contraction is a strength that is less than 20 units/minute averaged over a 10 minute period, e.g., less than 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 units/minute averaged over a 10 minute period.

[0092] In various embodiments, a contraction lasts between 30 and 45 seconds. In various embodiments, a reduced duration of contraction refers to contractions that are less than 30 seconds in length, e.g., less than 25, 20, 15, 10, or 5 seconds in length. [0093] In various embodiments, contractions occur at a frequency of 5-30 minutes between contractions (e.g., between the beginning of two contractions or between the end of two contractions or between the peak of two contractions), where frequency can be the period of time during which two contractions occur or the average period of time between contractions or the average period of time between a plurality of contractions that occur over a period. Frequency can be expressed as a period of time between contractions, an average period of time between contractions, or as the number of contractions that occur over a given period of time. In various embodiments, a reduces frequency of contractions refers to contractions occurring more than 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5 minutes apart.

[0094] Those of skill in the art will appreciate that labor, and the strength, frequency, and/or duration of contractions, can be individual to a given subject and therefore in any given instance a reduction may be a reduction of any value as compared to a relevant reference, where the reference may be a prior measure from the same subject, e.g., a measure taken in the immediately preceding 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours, or 96 hours. Accordingly, a reduction in the strength, frequency or duration of contractions can be medically relevant regardless of absolute value where the reduction can be determined by comparison to a relevant reference, e.g., a prior measure from the same subject.

[0095] Labor is considered preterm if it begins before 37 weeks of pregnancy have completed. Similarly, delivery during this period can be referred to as preterm delivery. In various embodiments of the present disclosure, a subject having preterm labor or preterm delivery has completed more than 20, 21, 22, 23, 24, or 25 weeks of pregnancy.

[0096] Preterm labor can include occurrence of a number of symptoms prior to completion of 37 weeks of pregnancy, including without limitation any of one or more of:

a) Contractions (e.g., contractions 10 minutes or less apart, e.g., less than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 minutes apart, optionally wherein contractions occur at intervals of less than 10 minutes over a period of 20, 30, 40, 50, 60, or more minutes)

b) Change in vaginal discharge (e.g., increased discharge, leaking fluid, or bleeding, e.g., spotting or light bleeding) c) Pelvic pressure indicative of downward pressure from the fetus

d) Cramping similar to menstrual cramping

e) Abdominal cramping

f) Backache (e.g., constant dull backache)

g) Nausea

h) Vomiting; or

i) Diarrhea

[0097] Preterm labor risk is increased among individuals with presence or history of the following risk factors:

a) Past preterm labor (personal or in family)

b) Past preterm delivery (personal or in family)

c) Infection (including without limitation infections of amniotic fluid or lower genital tract, e.g., during pregnancy)

d) Carrying more than one child (e.g., twins, triplets)

e) Tobacco use

f) Substance abuse

g) Smoking

h) Stress (including stressful events such as the death of a loved one)

i) High blood pressure

j) Preeclampsia

k) Diabetes

l) Blood clotting disorders

m) Overweight prior to pregnancy (e.g., BMI over 25, 30, 35, or 40)

n) Underweight prior to pregnancy (e.g., BMI under 18.5)

o) Low or high age (under 20 or over 35)

p) Low income

q) Lack of prenatal medical care

r) Certain fetal characteristics (e.g., a fetal birth defect)

s) Pregnancy by in vitro fertilization

t) Pregnancy shortly after a prior delivery (e.g., within 12 months) u) Pregnancy long after a prior delivery (e.g., more than 59 months)

v) Shortened cervix

w) Excess amniotic fluid (polyhydramnios)

[0098] Notwithstanding the above, those of skill in the art will appreciate that preterm labor also often occurs in individuals that do not present risk factors and/or do not present risk factors that caused or would cause a medical practitioner to diagnose a risk, increased risk, or significant risk of preterm delivery.

Treatment of Preterm Labor and/or Reduction of Contractions

[0099] The present disclosure provides, among other things, treatment of preterm labor and/or reduction of the strength, frequency, or duration of contractions. In various embodiments, the present disclosure includes a method of treatment of preterm labor and/or reduction of the strength, frequency, or duration of contractions that includes administering to a subject a contraction-regulatory compound of the present disclosure, e.g., niclosamide or a niclosamide analog. In various embodiments, the present disclosure includes a method of treatment of preterm labor and/or reduction of the strength, frequency, or duration of contractions in a subject in need thereof that includes administering to the subject a therapeutically effective amount of a contraction-regulatory compound of the present disclosure, e.g., niclosamide or a niclosamide analog. In various embodiments, a reduction in the strength, frequency, or duration of contractions is determined by comparison to a reference. In some embodiments, a reference is a reference measure or value. In some embodiments, a reference measure or value is a threshold measure or value. In some embodiments, a reference is a measure or value representative of a subject prior to administration of a contraction-regulatory compound of the present disclosure to the subject. In some embodiments, a reference is a measure or value that is representative of a reference population. In some embodiments, the reference population is a reference population of individuals not treated with a contraction-regulatory compound. In some embodiments, the reference population is a reference population of individuals treated with a standard of care for reducing the strength, frequency, or duration of contractions and/or for treating preterm labor. In some embodiments, the reference population is a reference population of individuals receiving a different treatment for reducing the strength, frequency, or duration of contractions and/or for treating preterm labor. Various methods and techniques for measuring the strength, frequency, or duration of contractions are known in the art and/or disclosed herein, together with qualitative and quantitative measures or values of contraction provided thereby. Moreover, those of skill in the art are familiar with the use of methods and techniques for measuring the strength, frequency, or duration of contractions and evaluating the data produced thereby.

[0100] In various embodiments, a method of the present invention for treatment of preterm labor treats (e.g., reduces or ameliorates) at least one symptom of preterm labor. In various embodiments, a method of the present invention for treatment of preterm labor reduces the strength, frequency, or duration of contractions.

[0101] In various embodiments, a method of the present invention for treatment of preterm labor causes or increases the likelihood of a delay in labor, delay in delivery, or non preterm birth as compared to a reference individual or population, e.g., an individual population that is not treated for preterm labor, is treated according to a standard of care, or is treated with a different treatment for preterm labor. Those of skill in the art will appreciate that treatment of preterm labor can be understood to cause, or increase the likelihood of, a delay in labor, delay in delivery, or non-preterm birth where administration of the drug results in a statistically significant difference and/or benefit between a population receiving a treatment of the present disclosure and a reference population receiving no treatment, a reference population receiving a standard of care treatment, and/or a reference population receiving a different treatment for preterm labor.

[0102] In various embodiments, a method of the present invention is used to reduce the strength, frequency, or duration of contractions in a context other than preterm labor, e.g., to delay a non-preterm labor, slow the progress of a non-preterm labor, and/or increase safety of a non-preterm labor for the benefit of one or both of a mother and a baby.

[0103] In various embodiments, administering a dose of a contraction-regulatory compound of the present disclosure to a subject reduces the strength, frequency, or duration of contractions for at least 1, 2, 3, 4, 5, or 6 hours. In various embodiments, administering a dose of a contraction-regulatory compound of the present disclosure to a subject reduces the strength, frequency, or duration of contractions for at least 12 hours, at least 24 hours, at least 48 hours, at least 72 hours, at least 96 hours, at least 120 hours, at least 1 week, or at least 2 weeks. In various embodiments, administering a dose of a contraction-regulatory compound of the present disclosure to a subject reduces the strength, frequency, or duration of contractions by a period of time having a lower bound of 1, 2, 3, 4, 5, 6, 12, or 24 hours and an upper bound of 12, 24, 48, 72, 96, 120 hours, 1 week, or 2 weeks.

[0104] In various embodiments, administering a dose of a contraction-regulatory compound of the present disclosure to a subject delays labor and or delivery by at least 1, 2, 3, 4, 5, or 6 hours. In various embodiments, administering a dose of a contraction-regulatory compound of the present disclosure to a subject delays labor and or delivery by at least 12 hours, at least 24 hours, at least 48 hours, at least 72 hours, at least 96 hours, at least 120 hours, at least 1 week, or at least 2 weeks. In various embodiments, administering a dose of a contraction- regulatory compound of the present disclosure to a subject delays labor and or delivery by a period of time having a lower bound of 1, 2, 3, 4, 5, 6, 12, or 24 hours and an upper bound of 12, 24, 48, 72, 96, 120 hours, 1 week, or 2 weeks.

[0105] In various embodiments, based at least in part on the duration of the effective of a dose of a contraction-regulatory compound of the present disclosure, a single dose of a contraction-regulatory compound of the present disclosure is sufficient to reduce the strength, frequency, or duration of contractions and/or delay delivery for at least 1, 2, 3, 4, 5, or 6 hours.

In various embodiments, based at least in part on the duration of the effective of a dose of a contraction-regulatory compound of the present disclosure, a single dose of a contraction- regulatory compound of the present disclosure is sufficient to reduce the strength, frequency, or duration of contractions and/or delay delivery for at least 12 hours, at least 24 hours, at least 48 hours, at least 72 hours, at least 96 hours, at least 120 hours, at least 1 week, or at least 2 weeks. In various embodiments, based at least in part on the duration of the effective of a dose of a contraction-regulatory compound of the present disclosure, a single dose of a contraction- regulatory compound of the present disclosure is sufficient to reduce the strength, frequency, or duration of contractions and/or delay delivery for a period of time having a lower bound of 1, 2, 3, 4, 5, 6, 12, or 24 hours and an upper bound of 12, 24, 48, 72, 96, 120 hours, 1 week, or 2 weeks. In various embodiments, use of a contraction-regulatory compound of the present disclosure requires administration of fewer unit dosages than administration of a standard of care contraction-regulatory compound. In various embodiments, use of a contraction-regulatory compound of the present disclosure requires administration of a lower total dosage than is required or recommended for use of a standard of care contraction-regulatory compound, e.g., to achieve a target or same reduction in the strength, frequency, or duration of contractions and/or delay of labor or delivery.

[0106] In various embodiments, a standard of care treatment for, e.g., treatment of labor includes administration of atosiban (TRACTOCILE®). Atosiban is an inhibitor of the hormones oxytocin and vasopressin and is administered intravenously to subjects in need thereof. In a typical atosiban dosing regimen includes three steps that can occur over a period of up to 48 hours. In a first step, atrosiban is administered as a 0.9 ml intravenous bolus injection given over 1 minute and delivering dose of 6.75 mg. In a second step, a 3 hour intravenous loading infusion of 300 pg/min is administered, delivering a total dose of 54 mg. In a third step, intravenous infusion of 100 pg/min is administered for up to 45 hours following Step 2, for delivery of a total third step dose of up to 270 mg

[0107] In various embodiments, a subject is a human subject, such as a pregnant human female. In various embodiments the subject is a non-human mammal, such as a pregnant female non-human mammal. In various embodiments the subject is an animal selected from a mouse, rat, cow, sheep, horse, giraffe, elephant, lion, tiger, bear, panda or non-human primate, e.g., where the animal is a pregnant female animal. For the avoidance of doubt, those of skill in the art will appreciate from context that various embodiments of the present disclosure, e.g., that relate to preterm labor as labor occurring prior to completion of the 37^th week of gestation, relate at least in part to a pregnant human female subject and/or to female human labor, and moreover that all references to a subject include at least a human subject unless otherwise indicated. Those of skill in the art will further appreciate that various embodiments, even if expressed in the context of a human subject, also disclose use in non-human mammals.

[0108] In certain embodiments, the subject has experienced one or more contractions prior to completion of the 37^th week of gestation. In certain embodiments, the subject has experienced two contractions no more than 10 minutes apart (e.g., less than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 minutes apart, optionally wherein contractions occur at intervals of less than 10 minutes over a period of 20, 30, 40, 50, 60, or more minutes) prior to completion of the 37^th week of gestation. In certain embodiments, the subject has been diagnosed as having preterm labor. In certain embodiments, the subject has been diagnosed as at risk of preterm labor. In certain embodiments, the subject has at least one symptom of preterm labor. In certain embodiments, the subject is characterized by at least one risk factor for preterm labor (e.g., presence or history of at least one risk factor for preterm labor).

[0109] In some embodiments the subject is a human female in at least the 16^th week of gestation. In some embodiments the subject is a human female in at least the 20^th, 21^st, 22^nd,

23^rd, 24^th, 25^th, 26^th, or 27^th week of gestation.

[0110] In some embodiments, a contraction-reducing agent of the present disclosure is administered to a subject who has not experienced uterine labor contractions during pregnancy, or who has not experienced two uterine labor contractions within a 10 minute period, but is expected to have such contractions, optionally where the subject is expected to have such contractions prior to completion of the 37^th week of pregnancy. In some embodiments, a contraction-reducing agent of the present disclosure is administered to a subject who has experienced uterine labor contractions during pregnancy, or who has experienced two uterine labor contractions within a 10 minute period (e.g., within a 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 minute period). In some embodiments, a contraction-reducing agent of the present disclosure is administered to a subject who is in labor, e.g., in that the subject has experienced a uterine labor contraction within the preceding 10 minutes (e.g., within the preceding 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 minutes) and is expected experience a further contraction within that 10 minute period. In some embodiments, a contraction-reducing agent of the present disclosure is administered to a subject who is having a contraction.

[0111] In some embodiments the subject has been administered a standard of care contraction-reducing compound. In some embodiments, the subject has been administered a contraction-reducing compound selected from a beta-2-adrenergic receptor agonist, a

nonsteroidal anti-inflammatory drug, and a calcium channel blocker. In some embodiments, the subject has been administered another contraction-reducing compound within 6 hours, 12 hours, 24 hours, 48 hours, 72 hours, 96 hours, or 120 hous of administration of a contraction-reducing compound of the present disclosure.

[0112] In some embodiments, a subject administered a contraction-reducing compound of the present disclosure is also administered a second contraction-reducing compound, optionally where the second contraction-reducing compound is a standard of care compound or where the second contract-reducing compound is selected from a beta-2-adrenergic receptor agonist, a nonsteroidal anti-inflammatory drug, and a calcium channel blocker.

[0113] Those of skill in the art will appreciate that assay data including contractility assay data presented in the Examples of the present disclosure are representative of the effect of a compound and/or ability of a compound to treat preterm labor and/or reduce the strength, frequency, or duration of contractions in cells, tissues, and/or subjects, e.g., human cells, tissues, and/or subjects. For instance, the present disclosure includes contractility assays that provide data representative of the duration of the effect (e.g., therapeutic benefit) of a contraction- regulatory compound, e.g., in reducing the strength, frequency, or duration of contractions in cells, tissues, and/or subjects, e.g., human cells, tissues, and/or subjects.

[0114] Those of skill in the art will further appreciate that distinct cell types necessarily include distinct physical properties (e.g., distinct proteomes and/or distinct signaling pathway or other functional characteristics). Accordingly, as is well known in the art, cell types can differ in their physiological responses to the same agent. Accordingly, an agent that is contraction- regulatory for a first cell type may or may not be contraction-regulatory (e.g., may not be significantly contraction regulatory, e.g., where significance refers to a demonstrated contraction z-score of less than -1, less than -2, less than -3, or less than -4, e.g., in a contractility assay of the present disclosure) with respect to a second distinct cell type. Moreover, even where a contraction-regulatory cell type may be contraction-regulatory with respect to each of a first cell type and a second cell type, delivery of the agent to cells of the respective types at a selected concentration may produce different contractility phenotypes, e.g., in the duration of effect and/or the extent to which administration of the agent reduces the strength, frequency, or duration of contraction, or the significance of any effect thereon. To provide one illustrative, non-liming example, an compound that is a contraction-reducing compound in uterine smooth muscle cells (e.g., USM cells) may not be a contraction-reducing compound (may not be a significant contraction-reducing compound) with respect to contraction of one or more other cell types, such as airway smooth muscle cells, or may be a contraction-reducing compound in another cell type but have different or unpredictable properties, such as duration of the effect and/or the extent to which administration of the agent reduces the strength, frequency, or duration of contraction.

Formulations and Administration

[0115] The present disclosure provides compositions that include a contraction- regulatory compound of the present disclosure or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier, adjuvant, or vehicle. In some embodiments, the therapeutic agent is present in a unit dose amount appropriate for administration to a subject, e.g., in a therapeutic regimen that shows a statistically significant probability of achieving a predetermined therapeutic effect when administered to a relevant population. In some embodiments, a pharmaceutical composition can be formulated for administration in a particular form (e.g., in a solid form or a liquid form), and/or can be specifically adapted for, for example: oral administration (for example, as a drenche (aqueous or non-aqueous solutions or

suspensions), tablet, capsule, bolus, powder, granule, paste, etc., which can be formulated specifically for example for buccal, sublingual, or systemic absorption); parenteral

administration (for example, by subcutaneous, intramuscular, intravenous or epidural injection as, for example, a sterile solution or suspension, or sustained-release formulation, etc.); topical application (for example, as a cream, ointment, patch or spray applied for example to skin, lungs, or oral cavity); intravaginal or intrarectal administration (for example, as a pessary, suppository, cream, or foam); ocular administration; nasal or pulmonary administration, etc.

[0116] Compositions of the present disclosure may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally, intraperitoneally,

intracisternallyor via an implanted reservoir. In some embodiments, the compositions are administered orally, intraperitoneally, or intravenously.

[0117] Sterile injectable forms of the compositions of this disclosure may be aqueous or oleaginous suspension. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium.

[0118] For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, such as carboxymethyl cellulose or similar dispersing agents that are commonly used in the formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions. Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation.

[0119] Injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

[0120] In order to prolong the effect of a compound of the present disclosure, it is often desirable to slow the absorption of the compound from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material with poor water solubility. The rate of absorption of the compound then depends upon its rate of dissolution that, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered compound form is accomplished by dissolving or suspending the compound in an oil vehicle. Injectable depot forms are made by forming microencapsule matrices of the compound in biodegradable polymers such as polylactide- polyglycolide. Depending upon the ratio of compound to polymer and the nature of the particular polymer employed, the rate of compound release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the compound in liposomes or microemulsions that are compatible with body tissues. [0121] In some embodiments, provided pharmaceutically acceptable compositions are formulated for oral administration. Such formulations may be administered with or without food. In some embodiments, pharmaceutically acceptable compositions of this disclosure are administered without food. In other embodiments, pharmaceutically acceptable compositions of this disclosure are administered with food. Pharmaceutically acceptable compositions of this disclosure may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried cornstarch. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents may also be added.

[0122] Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidinone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and/or i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents.

[0123] Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polethylene glycols and the like.

[0124] The active compounds can also be in micro-encapsulated form with one or more excipients as noted above. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings, release controlling coatings and other coatings well known in the pharmaceutical formulating art. In such solid dosage forms the active compound may be admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms may also include, as is normal practice, additional substances other than inert diluents, e.g., tableting lubricants and other tableting aids such a magnesium stearate and microcrystalline cellulose. In the case of capsules, tablets and pills, the dosage forms may also include buffering agents. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes.

[0125] Liquid dosage forms for oral administration include, but are not limited to, pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

[0126] Alternatively, pharmaceutically acceptable compositions of this disclosure may be administered in the form of suppositories for rectal administration. These can be prepared by mixing the agent with a suitable non-irritating excipient that is solid at room temperature but liquid at rectal temperature and therefore will melt in the rectum to release the drug. Such materials include cocoa butter, beeswax and polyethylene glycols.

[0127] Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compounds of this disclosure with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at ambient temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound.

[0128] Pharmaceutically acceptable compositions of this disclosure may also be administered topically, especially when the target of treatment includes areas or organs readily accessible by topical application, including diseases of the eye, the skin, or the lower intestinal tract. Suitable topical formulations are readily prepared for each of these areas or organs.

[0129] Topical application for the lower intestinal tract can be effected in a rectal suppository formulation (see above) or in a suitable enema formulation. Topically-transdermal patches may also be used.

[0130] For topical applications, provided pharmaceutically acceptable compositions may be formulated in a suitable ointment containing the active component suspended or dissolved in one or more carriers. Carriers for topical administration of compounds of this disclosure include, but are not limited to, mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax and water. Alternatively, provided pharmaceutically acceptable compositions can be formulated in a suitable lotion or cream containing the active components suspended or dissolved in one or more pharmaceutically acceptable carriers. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water.

[0131] For ophthalmic use, provided pharmaceutically acceptable compositions may be formulated as micronized suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions in isotonic, pH adjusted sterile saline, either with or without a preservative such as benzyl alkonium chloride. Alternatively, for ophthalmic uses, the pharmaceutically acceptable compositions may be formulated in an ointment such as petrolatum. [0132] Pharmaceutically acceptable compositions of this disclosure may also be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other conventional solubilizing or dispersing agents.

[0133] Dosage forms for topical or transdermal administration of a compound of this disclosure include ointments, pastes, creams, lotions, gels, powders, solutions, sprays, inhalants or patches. The active component is admixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives or buffers as may be required. Ophthalmic formulation, ear drops, and eye drops are also contemplated as being within the scope of this disclosure. Additionally, the present disclosure contemplates the use of transdermal patches, which have the added advantage of providing controlled delivery of a compound to the body. Such dosage forms can be made by dissolving or dispensing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate can be controlled by either providing a rate controlling membrane or by dispersing the compound in a polymer matrix or gel.

[0134] In various embodiments, a contraction-regulatory compound of the present disclosure (such as niclosamide or a niclosamide analog) is delivered to a subject intravenously. In various embodiments, a contraction-regulatory compound of the present disclosure (such as niclosamide or a niclosamide analog) is orally delivered to a subject, e.g., in the form of a tablet. In various embodiments, an intravenous dosage of a contraction-regulatory compound of the present disclosure is administered to a subject in need thereof at a total dosage of lOmg to 5.0g over a course of treatment. In various embodiments, the total dosage delivered to a subject in need thereof is about 10, 20, 30, 40, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,500, 3,000, 3,500, 4,000, 4,500, or 5,000 mg. In some embodiments the total dosage is delivered continuously. In some embodiments, the total dosage is delivered discontinuously. In some embodiments, the total dosage is delivered at a constant rate of delivery to the subject. In some embodiments, the total dosage is delivered at a variable rate of delivery to the subject. In some embodiments, the course of treatment from first delivery of contraction-regulatory agent to completion of delivery of the total dosage occurs over a period that is equal to or less than 10 minutes (e.g., in the case of a single bolus injection). In some embodiments, the course of treatment from first delivery of contraction-regulatory agent to completion of delivery of the total dosage occurs over a period that is equal to or less than 20 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 84 hours, 96 hours, 108 hours, 120 hours, 1 week, or 2 weeks.

EXAMPLES

[0135] The present Examples provide contraction-regulatory compounds and illustrate that such compounds are useful in treating preterm labor. Assays disclosed in the present Examples provide data representative of the effect of a compound and/or ability of a compound to treat preterm labor and/or reduce the strength, frequency, or duration of contractions in cells, tissues, and/or subjects, e.g., human cells, tissues, and/or subjects. For instance, the present disclosure includes contractility assays that provide data representative of the duration of the effect (e.g., therapeutic benefit) of a contraction-regulatory compound, e.g., in reducing the strength, frequency, or duration of contractions in cells, tissues, and/or subjects, e.g., human cells, tissues, and/or subjects.

Example 1: Identification of inhibitors of primary human uterine smooth muscle cell contractility

[0136] Contraction-regulatory compounds useful, e.g., in the treatment of preterm labor were identified by a high-throughput screen of annotated small molecule compounds.

[0137] Prevalence of pre-term labor and treatment limitations-

[0138] Preterm birth is the leading cause of infant mortality and morbidity for which efficacious preventative treatments are essentially absent. Preterm labor occurring prior to 37 weeks of gestation is associated with up to 18% of all births[l] and significantly increases the risks numerous health complications including sleep apnea, respiratory distress syndrome, and intraventicular hemorrhage, and many others. These effects on infant health are so dire that according to the CDC, they caused 17% of infant deaths in 2015, and in 2005, medical costs associated with pre-term births exceeded $26B (or $51,600 per preterm infant)[2]. [0139] Treatments preventing pre-term birth are extremely limited.

[0140] Limited or no agents have been approved by the FDA as treatment for at-risk mothers who suffered a prior preterm birth. According to one study, weekly injection with the hormone progesterone beginning around week 16 through the end of gestation indicated specifically for at-risk mothers who suffered a prior preterm birth[3]. Although this treatment reportedly decreased incidence of pre-term births by one-third, it benefits only ideal candidates who meet the risk criteria and promptly and faithfully receive treatment. Moreover, a 2017 NIH study found that testing for fetal fibronectin or short cervix - the two methods that were once expected to predict pre-term labor in first-time pregnancies - were only useful in a small subset of cases and are not generally applicable for widespread screening[4]. To provide one particular example, hydroxyprogesterone caproate (Makena) is a progestin indicated to reduce the risk of preterm birth in women pregnant with a single baby who have a history of singleton spontaneous preterm birth, but studies reviewed by the FDA have shown no benefit and an advisory committee has recommended withdrawal of FDA approval .

[0141] Without the ability to reasonably predict spontaneous pre-term labor and begin preventative treatment prior, it is impossible to prevent early births using progesterone treatment.

[0142] Cellular force generation and pre-term labor-

[0143] There is a need for new therapies to prevent pre-term delivery by safely and specifically targeting uterine smooth muscle (USM) contractility pathways in order to restore uterine quiescence during spontaneous pre-term labor, particularly in orthogonal pathways to existing tocolytics which take effect only temporarily. The other pre-term birth management strategy is to target increased uterine contractility that functionally drives spontaneous pre-term labor (which leads to 70% of preterm births [1]).

[0144] Currently, short-term pregnancy prolongation can be possible via a class of drugs called tocolytics that work to diminish uterine smooth muscle contraction through a number of pathways including beta-2-adrenergic receptor agonism, blocking of calcium channels or antagonism of calcium itself[5]. However, the compounds comprising existing clinical treatments, which can have considerable side-effects, are only able to delay delivery for at-most 24-48 hours due, in part, to rapid desensitization and receptor down-regulation in the smooth muscle. Indeed, this strategy relies on delaying birth just long enough to administer antenatal corticosteroids and other therapies to reduce health risks for the baby. Thus, there is an unmet clinical need for therapies, and drugs that can be delivered immediately at the onset of early labor and are able to indefinitely suspend delivery until full term is reached.

[0145] Summary

[0146] Using a novel assay that allows characterizing contractility in primary human uterine cells for, to the present inventors’ knowledge, the first time, a high-throughput screening of 2560 small molecules was performed in order to identify functional inhibitors of primary human uterine smooth muscle cell contractility with potential clinical tocolytic activity, which inhibitors would therefore be identified as contraction-regulatory compounds of the present disclosure. Multiple highly effective substances - Dihydroouabain, Piperlongumine,

Niclosamide, Stevioside, JW74, U-73343, ONO-RS-082, Thapsigargin, PD173952, Amisulpride, AC-55649, Gliclazide, Tetracaine hydrochloride, Lanatoside C, Proscillaridin A, GR 127935 hydrochloride hydrate, NAN- 190 hydrobromide, and MRS 2159 - were identified and confirmed. All of these molecules had been previously studied in the context of other unrelated therapeutic areas either in vitro, in vivo, or even in clinical trials. Some are approved by the FDA for unrelated conditions.

[0147] Despite these prior studies of their uses for purposes other than for the treatment of preterm labor and their inclusion in commonly screened chemical libraries (LOP AC and Prestwick Chemical Library), those skilled in the art will appreciate that these molecules have never, to the knowledge of the present inventors, previously been described or supposed as having tocolytic properties. It is, therefore, very surprising and unexpected that these molecules were found to relax human uterine smooth muscle. As it was impossible to anticipate these results based on known data for these compounds, the inventors uncovered these properties through the use of a new proprietary and target-agnostic phenotypic assay of cellular contractile force (FLECS Technology by Forcyte Biotechnologies, Inc).

[0148] Identification of contraction-regulatory compounds

[0149] A workflow for identification of contraction-regulatory compounds is provided in

Figure 1C. This functional phenotypic screen of cellular contractility in primary human uterine smooth muscle cells was performed following the protocol described herein: [0150] Assay well-plates known as“FLECS-plates,” developed by Forcyte

Biotechnologies, for the purpose of measuring cellular contractile force were fabricated by Forcyte Biotechnologies. The specific technology behind this assay is described in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002; see also, e.g., U.S. Pat. Nos. 10,082,497 and 10,473,644) (each of which is incorporated herein by reference with respect to contractility assays and in its entirety) which is incorporated by reference. This assay hardware is made available for purchase by Forcyte Biotechnologies to all interested users.

[0151] Principles of this high-throughput contractility assay, which provides single-cell resolution, are depicted in FIG. 1 A-B, and are further described in International Application No. PCT/US20/22439 and International Application No. PCT/US15/23136 (published as

WO/2015/149002; see also, e.g., U.S. Pat. Nos. 10,082,497 and 10,473,644), each of which is incorporated herein by reference with respect to contractility assays and in its entirety. The assay provides single-cell contraction measurements from one or more individual cells under selected experimental conditions. At least one example of FLECS technology is found in Pushkarsky T, “FLECS Technology for High-Throughput Single-Cell Force Biology and Screening,” Assay Drug Dev Technol. 2018 Jan 1; 16(1): 7-11.

[0152] For the high-throughput screen, sufficient screen-ready FLECSplates in 384- wellplate format were manufactured from the same materials on the same day. Cells for the high-throughput screen included two distinct primary human uterine cell lines, which were grown to confluency in the days preceding the screen and serum starved in the flask during the 24 hours before seeding to FLECSplates. On the day of screening, each of the annotated small molecule compounds was delivered to FECSplates wells at a concentration of 1 OmM in 0.5% DMSO before seeding cells to the FLECSplate wells. This procedure avoids exposure of cells to high concentrations of DMSO, which takes time to diffuse into an aqueous medium.

[0153] In this particular high-throughput screening campaign,‘X’-shaped micropatterns were used. The sizing of the‘X’ micropattems was 70 micron diagonal lengths, and 10 micron bar thickness. The adhesive protein was BioReagent grade Type IV collagen from human placenta, purchased from Sigma Aldrich. The fluorescent protein was human fibrinogen conjugated to Alexa Fluor 546 dye which has an excitation maximum 556 nanometers and an emission maximum at 573 nanometers. The stiffness of the elastomeric layer was approximately 12 kPa. Specifically, the ratio of the base to the crosslinking agent of the 2-component elastomer was 1 : 1.6. The wellplate size was 384-wells.

[0154] Primary human uterine smooth muscle (USM) cells were purchased from

Sciencell and cultured in Ham’s F12 base, supplemented with 10% FBS and additional buffers that support robust cell growth and attachment. Cells were thawed, and cultured out to 4 passages before performing the screen. Cells were serum starved during the 24 hours preceding the screen.

[0155] On the day of the screen, a Biomek FX was used to pin 500 nL of LOP AC and

Prestwick Chemical Library compounds into 8 total 384-well FLECSplates pre-filled with 25 microliters of cell culture media. Columns 2 and 23 received 500nL of DMSO only. Columns 1 and 24 received nothing. Following the pinning, 25 microliters of USM cell suspension at a concentration of approximately 70,000 cells/mL were added to each well of each plate. The final DMSO concentration was therefore 0.5% in all wells except those wells in columns 1 and 24.

The final drug concentration was 10 mM.

[0156] Following cell seeding, plates were left out at room temperature for an hour to facilitate uniform cell settling to the bottom to help achieve single-cell distributions on the micropattems. Next, the plates were placed into a 37C incubator with 5% C02.

[0157] At 6 hours after placing the plates into the incubator, the plates were removed and imaged using the ImageXpress XL imaging system (Molecular Devices), one plate at a time. At this timepoint, only the micropattems were imaged because cell nuclear stain was not added until the final timepoint to avoid any effects associated with long-term incubation with the DNA- binding dye. After imaging, plates were placed back into the incubator.

[0158] After another 18 hours, or 24 hours total following cell attachment, the plates were dosed with live cell nuclear stain (Hoechst 33342 at a 1 : 10,000 dilution) and the plates were imaged again, this time imaging both the micropattems and the cell nuclei. Registration of the images taken at 6 hours to those taken at 24 hours and to the images of the cell nuclei was straightforward and automated due to the minimal drift in the position of the plates within the ImageXpress imaging system. [0159] After imaging was completed, all images were downloaded to a local server where a MATLAB-based program was used to perform quantification of cellular contraction as depicted in FIG. IB. Numeric results for median contraction in each well were uploaded to CDD Vault where data on each plate was normalized to the control wells on the same plate (columns 2 and 23). Hits were defined as wells with a contraction z-score <-2.5. Z-scores were calculated against negative control replicates of each assay FLECSplate. Specifically, a hit at the 6 hr timepoint suggests the compound is fast-acting, whereas a hit at 24 hrs suggests the compound is long-acting. 163 compounds were considered hits after the initial analysis.

[0160] In the high-throughput screen, contraction images were acquired at 6 and 24 hours after cell seeding. Of the annotated small molecule compounds, agents conferring a contraction z-score <-3 and a cell count z-score >-l (indicating no acute toxicity) relative to DMSO-only controls were selected as contraction-regulatory compounds. The high-throughput screen yielded 163 contraction-regulatory compounds.

[0161] Before further testing, each hit was evaluated for cytotoxicity and known teratogenicity. Cytotoxicity was evaluated by considering the cell count z-score whereby a cell count z-score >-l was selected to be the threshold below which cytotoxicity was suspected.

[0162] Potential for teratogenicity was determined by performing literature searches of all published work and clinical data available for the compounds. Compounds of pregnancy class C or D or X, compounds known to arrest cell cycle and compounds with reported toxicity at low doses were all deprioritized. This analysis reduced the candidate count from 163 to 55.

[0163] A subset of 55 contraction-regulatory compounds were selected for further analysis after (i) eliminating compounds with known teratology (US Pregnancy Class X), such as many statins or toxins, or those that arrest cell cycle or otherwise kill cells via induction of apoptosis; (ii) eliminating compounds known to cause abortion; and (iii) eliminating certain agents that also were found to significantly regulate contraction (e.g., where significance refers to a demonstrated contraction z-score of less than -1, less than -2, less than -3, or less than -4 under the same conditions, e.g., in a contractility assay of the present Examples) of other human cell types tested in the present assay format (airway SMCs, vascular SMCs, bladder SMCs, dermal fibroblasts, and hepatic stellate cells), e.g., in a manner that could be dangerous to systemic health in an organism, while retaining certain contraction-regulatory compounds found to be especially effective in regulatory contraction of uterine cells. Thus, the present Example demonstrates that a compound that is contraction-reducing in a first cell type, such as USM cells, may not be a contraction-reducing compound with respect to contraction of one or more other cell types (and/or may not be a significantly contraction-reducing compound with respect to contraction of one or more other cell types), such as arterial cells (to provide one non-limiting example).

[0164] The contraction-regulatory compounds of the 55 compound subset were further analyzed in triplicate confirmatory assays at doses of 1 mM, 5 mM, and 10 pM, with z-scores for contraction and cell count evaluated at 6 hrs and 24 hrs. Four compounds known to regulate uterine contraction were confirmed as contraction-regulatory compounds from among the 55 compounds (FIG. 3). These include the progestins norgestrel-D, norethindrone, and ethisterone, and the molecule rofecoxib, a COX2 inhibitor which was once evaluated in a short trial [¹⁴].

[0165] These 55 compounds were rescreened in 3 plates, following the exact procedures as before, but now at the concentrations of lOpM, 5pM, and lpM. Contraction z-score was again used to evaluate efficacy, whereby compounds with a 24 hours contraction z-score<-2.5 for lOpM and z-score <-1.5 at 5pM, and preferably z-score<-l at lpM were considered confirmed. In total, 25 hits were confirmed using these cut-offs, and many others showed weaker signals supporting their ability to relax USM contraction.

[0166] Of the confirmed hits that relaxed USM contraction, several comprised non-novel compounds previously described as having tocolytic properties (depicted in FIG. 3).

Specifically, these included Norgestrel-(-)-D, norethindrone, and ethisterone, all of which represent the progestin class of molecules, which have been described as possessing value as tocolytics[7]. In addition, experiments and data of the present Example also confirmed rofecoxib, a COX-2 selective nonsteroidal anti-inflammatory drug (NS AID), as a hit relaxing USM contraction. Refocoxib has previously been studied as a tocolytic by others[8].

Confirmation of such hits validated the functional predictivity of the assay.

[0167] The remaining confirmed hits, a total of 21, are found by the inventors to have functionally demonstrated and novel tocolytic effects. Contraction z-scores for the confirmation screens performed by the inventors are depicted in FIG. 2. These compositions have been placed into Group 1 or Group 2 or Group 3, defined below and depicted in FIG. 4, FIG. 5 and FIG. 6. [0168] The disclosure therefore pertains to the use of a composition comprising a molecule belonging to one of Group 1, Group 2, or Group 3, listed below, to relax, slow, suppress or reduce mechanical contractile force or contractile tone of the human uterus. The present disclosure compositions and methods can be applied to reduce the risk of premature labor in a subject at risk therefor. The present disclosure compositions and methods can be applied to delay preterm birth in a subject at risk therefor.

[0169] The present disclosure also provides compositions and methods to stop labor in preparation to Cesarean delivery.

[0170] The present disclosure also provides compositions and methods to reduce severe menstrual cramping through the relaxation of uterine smooth muscle.

[0171] In one aspect of the disclosure, the compositions possessing these properties that include relaxing, slowing, suppressing or reducing mechanical contractile force or contractile tone of uterine smooth muscle cells comprise a molecule belonging to Group 1 which contains the following: Piperlongumine, JW74, U-73343, ONO-RS-082, Thapsigargin, PD173952, Amisulpride, AC-55649, Gliclazide, Tetracaine hydrochloride, GR 127935 hydrochloride hydrate, NAN- 190 hydrobromide, and MRS 2159 (all depicted in FIG. 4). These compounds have been directly shown by the inventors to be effective in relaxing uterine smooth muscle cell contraction in vitro without conferring cytotoxicity. In various embodiments, molecules from Group 1 are chemically modified with additions or subtractions of chemical groups or functional groups, using chemical techniques known to persons skilled in the art. In various embodiments, these modified compositions possess superior solubility or efficacy properties.

[0172] Piperlongumine, which is a cell-permeable, orally bioavailable natural product isolated from the plant species, Piper longum L, has been studied as an anti-cancer agent.

[0173] JW74, which is a specific inhibitor of the canonical Wnt signaling, has been studied as an anti-cancer agent.

[0174] U-73343, is an inactive analog of U 73122.

[0175] ONO-RS-082, is a reversible inhibitor of Ca2+-independent phospholipase A2.

[0176] Thapsigargin is a non-competitive inhibitor of the sarco/endoplasmic reticulum

Ca2+ ATPase (SERCA).

[0177] PD173952 is a Src family kinase inhibitor. [0178] Amisulpride, which is a benzamide, is an antipsychotic medication used to treat schizophrenia.

[0179] AC-55649, a subtype selective RAR (RARP2) agonist. AC-55649 is a potent, orally available isoform selective Retinoic Acid Receptor b2 agonist.

[0180] Gliclazide, is an anti-diabetic medication used to treat diabetes mellitus type 2.

[0181] Tetracaine hydrochloride, is a local anesthetic used to numb the eyes, nose, or throat.

[0182] GR 127935 hydrochloride hydrate, is a selective and orally active 5-HT1B/1D serotonin receptor antagonist.

[0183] NAN-190 hydrobromide, is a 5-HT1A serotonin receptor antagonist active in the nM range.

[0184] MRS 2159 is a P2X1 purinoceptor antagonist.

[0185] In another aspect of the disclosure, the compositions possessing these properties that include relaxing, slowing, suppressing or reducing mechanical contractile force or contractile tone of uterine smooth muscle cells comprise a molecule belonging to Group 2 which contains niclosamide (depicted in FIG. 5 A) and its derivatives represented by FIG. 5B. In various embodiments, niclosamide is chemically modified with additions or subtractions of chemical groups or functional groups, using chemical techniques known to persons skilled in the art. Niclosamide has been directly shown by the inventors to be effective in relaxing uterine smooth muscle cell contraction in vitro, at 10 mM, 5mM and ImM doses, at short timescales, e.g. by 6 hours after administration, and at long timescales, e..g still at 24 hours after administration, without conferring cytotoxicity. In various embodiments, these derivatives of niclosamide possess superior solubility, bioavailability or efficacy properties.

[0186] Niclosamide, which is a chlorinated salicylanilide pesticide principally used against aquatic vertebrates and crustaceans. It is an anthelmintic effective in the treatment of diphyllobothriasis, diphyllobothriasis, hymenolepiasis. It is used to treat broad tapeworms (or fish, dwarf and beef).

[0187] In another aspect of the disclosure, the compositions possessing these properties that include relaxing, slowing, suppressing or reducing mechanical contractile force or contractile tone of uterine smooth muscle cells comprise a molecule belonging to Group 3 which contains cardiac glycosides (depicted in FIG. 6). Cardiac glycosides are molecules with a structure comprising a steroid molecule consisting of four fused rings, that is attached to a glycoside and an R group. In various embodiments, the R group is also a glycoside. In one instance, the cardiac glycoside is one of: Dihydroouabain, Stevioside, Lanatoside C, or

Proscillaridin A (all depicted in FIG. 6B-E). These specific cardiac glycosides have been directly shown by the inventors to be effective in relaxing uterine smooth muscle cell contraction in vitro without conferring cytotoxicity. Those skilled in the art will appreciate that the data provided by the inventors regarding the functionally efficacy of these specific cardiac glycosides supports the expectation that additional cardiac glycosides that follow the general structure described, will also exhibit efficacy in relaxing uterine smooth muscle contraction, and thus also possess potential clinical utility. In various embodiments, molecules from this Group 3 are suitable for local administration to the uterine tissue. In various embodiments, molecules from Group 3 are suitable for delivery by suppository.

[0188] Dihyrooubain, which is a cardiac glycoside, is an inhibitor of the sodium- potassium pump.

[0189] Stevioside, which is a diterpene glycoside, is used as a non-caloric sweetener.

[0190] Lanatoside C, which is a cardiac glycoside, is chiefly indicated for atrial fibrilation and paroxysmal supraventricular tachycardia.

[0191] Proscillaridin A, which is a cardiac glycoside, has also been studied as an anti cancer agent.

[0192] The disclosure pertains to the administration of a therapeutically effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3 to a female subject experiencing uterine contractions for the purpose of arresting, reducing, or slowing the uterine contractions. In some instances, the female subject is pregnant and the purpose is to delay birth of her child.

[0193] The disclosure further pertains to the use of a composition comprising a molecule belonging to Groups 1, 2 or 3 to affect the contractions or contractile tone produced by the uterus of a female subject. In some instances, the female subject is pregnant. [0194] In one aspect, the disclosure provides a method of suppressing uterine contractions in female subjects with an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3.

[0195] In another aspect, the disclosure provides a method of suppressing uterine contractions in pregnant female subjects with an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3.

[0196] In another aspect, the disclosure provides a method of reducing contractile tone of uterine smooth muscle in female subjects with an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3. In some embodiments, the uterine smooth muscle cells have been contacted with a tocolytic compound.

[0197] In another aspect, the disclosure provides a method of reducing contractile tone of uterine smooth muscle in pregnant female subjects with an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3. In some embodiments, the uterine smooth muscle cells have been contacted with a tocolytic compound.

[0198] In another aspect, the disclosure provides a method of delaying birth by a pregnant female subject with the use of an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3. In another aspect, the disclosure provides a method of treating preterm labor in pregnant female subjects with the use of an effective amount of a composition comprising a molecule belonging to Groups 1, 2, or 3.

[0199] In another aspect, the disclosure provides a method of delaying birth by a pregnant mammal with the use of an effective amount of a composition comprising a molecule belonging to Groups 1, 2 or 3.

[0200] The compositions for relaxing uterine smooth muscle contractions will typically be administered to the patient in a dose regimen that provides for the most effective relaxation of the uterine smooth muscle contractions (from both efficacy and safety perspectives) for which the patient is being treated, as known in the art. In conducting the treatment method of the present disclosure, the compositions for relaxing uterine smooth muscle contractions can be administered in any effective manner known in the art, such as by oral, topical, intravenous, intra-peritoneal, intramuscular, intra-articular, subcutaneous, intranasal, intra-ocular, vaginal, rectal, or intradermal routes. [0201] In various embodiments, the compositions described herein are administered to the subject prior to the subject experiencing uterine contractions.

[0202] In various embodiments, the compositions described herein are administered to the subject at the time the subject is experiencing uterine contractions.

[0203] In various embodiments, the compositions described herein are administered to the subject following an episode of uterine contractions but at a time at which the subject is not actively experiencing uterine contractions.

[0204] In another aspect of the disclosure, the composition for relaxing uterine smooth muscle contraction comprises a combination of two or more molecules selected from Groups 1, 2 or 3.

[0205] In another aspect of the disclosure, the compositions for relaxing uterine smooth muscle contraction comprises a combination of one or more molecules belonging to Group 1 and one or more molecule belonging to Group 2.

[0206] In another aspect of the disclosure, the compositions for relaxing uterine smooth muscle contraction comprises a combination of one or more molecules belonging to Group 1 and one or more molecule belonging to Group 3.

[0207] In another aspect of the disclosure, the compositions for relaxing uterine smooth muscle contraction comprises a combination of one or more molecules belonging to Group 2 and one or more molecule belonging to Group 3.

[0208] In another aspect of the disclosure, the compositions for relaxing uterine smooth muscle contraction comprises a combination of one or more molecules belonging to Group 1, Group 2, or Group 3 and progesterone administration following week 16 of pregnancy.

[0209] In another aspect of the disclosure, the compositions for relaxing uterine smooth muscle contraction comprises a combination of one or more molecules belonging to Group 1, Group 2, or Group 3 and other currently used tocolytics such as beta-2-adrenergic receptor agonists, NSAIDs, calcium channel blockers.

[0210] With regards to embodiments comprising combinations of compositions, the combinations can be delivered simultaneously to the subject using delivery methods described herein. Alternatively, the combinations of compositions can be delivered in a staggered fashion in time and/or for different time periods to the subject through the same and/or separate delivery methods described herein. Especially, the delivery time and time periods of delivery should be designed based on the pharmacokinetics of each composition to maintain a therapeutic dose in the uterine tissue for an extended time period.

[0211] FIG. 1 illustrates the method utilized by the inventors to identify the named molecules as having potent tocolytic properties. FIG. 1 A illustrates a schematic of the FLECS highthroughput cellular contractility screening assay that was performed with primary human uterine smooth muscle cells. Multi -wellplates comprising 384 wells having elastomeric bottoms with precisely micropatterned adhesive and fluorescent proteins, as described in International Application No. PCT/US20/22439 and/or International Application No. PCT/US15/23136 (published as WO/2015/149002; see also, e.g., U.S. Pat. Nos. 10,082,497 and 10,473,644) (each of which is incorporated herein by reference with respect to contractility assays and in its entirety) were produced by Forcyte Biotechnologies. Compounds from the LOP AC and

Prestwick Chemical Library collections were pinned into a total of 8 such plates. Primary human uterine smooth muscle cells purchased from vendors were seeded into these plates following the addition of test compounds. The fluorescent micropattems presented on the wellplates and the labeled cell nuclei were imaged 6 and 24 hours following introduction of cells. Mechanical forces exerted by the cells contracted and reduced the visible footprints of the micropattems.

The size changes of micropattems in wells with drug were compared to the size changes of micropattems in wells with only vehicle controls. MATLAB software was used to perform this analysis on a computer. Compounds found to have prevented or reversed micropattern size changes sufficiently compared to a threshold value were considered hits.

[0212] FIG. 1 A also depicts an actual image pair of the micropattems and cell nuclei from a common well on a well-plate. Such image data was used to quantify the effects of test compounds on uterine smooth muscle cell contractility.

[0213] FIG. IB depicts the algorithm used to analysis the image data. In the first step, all micropattems present in an image are identified and their orientation is determined. In the second step, the vicinity of each micropattem is checked for the presence of a stained cell nucleus. Micropattems are then sorted as having i) no bound cells, ii) one bound cell, or iii) more than one bound cell. Micropattems having either no bound cells or one bound cell are measured in size. Contraction is defined as the difference between the size of micropattem possessing a single bound cell and the median measurement of the collection of micropatterns possessing no bound cells. This algorithm was coded in MATLAB.

[0214] FIG. 1C depicts a summary of the high-throughput screening. Compounds were first identified as hits in a primary screen. Compounds were not further considered if there was known teratogenicity or cytotoxicity and the remaining compounds were then rescreened three times and confirmed to have potency at multiple dosages. This yielded the lists of compositions as described herein.

[0215] FIG. 2 reports results from the confirmation screening step of the screening workflow (used by the inventors to confirm hits found in a prior primary screen ) for compounds found by the inventors to have previously unknown tocolytic properties, as reported herein. Compounds identified as viable and safe hits in an early screen were rescreened at 3 dosages.

[0216] FIG. 2A reports the z-scores of the measured uterine smooth muscle cell contractions at the 24hr observation timepoint.

[0217] FIG. 2B reports the z-scores of the measured uterine smooth muscle cell contractions at the 6hr observation timepoint. Controls were no-compound vehicle additions (0.5%, 0.025% or 0.05% DMSO). Clear efficacy in reducing or reversing uterine smooth muscle cell contraction is demonstrated for each compound, relative to no treatment.

[0218] FIG. 3 reports results from the confirmation screening step of the screening workflow (used by the inventors to confirm hits found in a prior primary screen) for compounds with previously reported and known tocolytic uses. Z-scores of the measured uterine smooth muscle cell contractions at the 24hr observation timepoint are displayed. These findings offer strong validation that the screening methodology employed herein is robust and predictive.

Works Cited

[0219] 1. Romero, R., Dey, S. K. & Fisher, S. J. Preterm labor: One syndrome, many causes. Science 345, 760-765 (2014).

[0220] 2. Institute of Medicine (US) Committee on Understanding Premature Birth and

Assuring Healthy Outcomes. Preterm Birth: Causes, Consequences, and Prevention. (National Academies Press (US), 2007). [0221] 3. Meis, P. J. et al. Prevention of recurrent preterm delivery by 17 alpha- hydroxyprogesterone caproate. N. Engl. J. Med. 348, 2379-2385 (2003).

[0222] 4. Esplin, M. S. et al. Predictive Accuracy of Serial Transvaginal Cervical

Lengths and Quantitative Vaginal Fetal Fibronectin Levels for Spontaneous Preterm Birth Among Nulliparous Women. JAMA 317, 1047- 1056 (2017).

[0223] 5. Haas, D. M., Benjamin, T., Sawyer, R. & Quinney, S. K. Short-term tocolytics for preterm delivery - current perspectives. Int J Womens Health 6, 343-349 (2014).

[0224] 6. L1S20180356396A1 Device and method for force phenotyping of cells for high-throughput screening and analysis. Dino Di Carlo, Peter Tseng, Ivan Pushkarsky

[0225] 7. Lucovnik, M. et al. Progestin treatment for the prevention of preterm birth.

Acta Obstetricia et Gynecologica Scandinavica 90, 1057-1069 (2011).

[0226] 8. McWhorter, J., Carlan, S. J., OLeary, T. D., Richichi, K. & OBrien, W. F.

Rofecoxib versus magnesium sulfate to arrest preterm labor: a randomized trial. Obstet Gynecol 103, 923-930 (2004).

Example 2: Identification of Long-Acting Contraction-Regulatory compounds

[0227] Many known agents that have been proposed as contraction-regulatory compounds, e.g., for treatment of preterm labor are short-acting. Exemplary agents previously studied as contraction-regulatory compounds, e.g., for treatment of preterm labor, include ritodrine and nifedipine. The commonly used calcium channel blocker Nifedipine is considered to be among the best-performing tocolytic agents [¹³] in use today, while the beta-agonist, ritodrine has been removed from the US market due to safety concerns. In the present Example, these agents were analyzed in a cell contraction assay as described in Example 1 using primary uterine smooth muscle cells. Results shown in FIG. 7 demonstrate that, while both ritodrine and nifedipine were effective in significantly decreasing percent contraction shortly after delivery (within the first 30 minutes), they became substantially less effective over time, as shown by an increase in contraction at 5 hours as compared to 30 minutes, with percent contraction returning to control levels at 5 hours (control data not shown). The significant decrease in percent contraction was only maintained for 30-60 minutes (60 minute data not shown). Because short acting characteristics of various agents has been clinically problematic, these data underscore and are representative of a clinical challenge in treatment of preterm labor. Clinically, ritodrine and nifedipine provide only limited clinical benefit due to a loss of efficacy beyond a short time window of only 24-48 hours. Contraction-regulatory compounds for treatment of preterm labor with longer and/or more sustained efficacy, which can be measured in the assay used in the present Example and in Example 1.

[0228] The assay disclosed in Example 1 and utilized herein differentiates short-acting and long-acting contraction-regulatory compounds. The present assay provides a clinically relevant measure of the duration of contraction-regulatory compound efficacy. Contraction- regulatory compounds identified in Example 1 included Niclosamide, PD173952, Tetracaine, and JW74.

[0229] Dose response titrations of Niclosamide, PD 173952, Tetracaine, and JW74 for contraction of the uterine smooth muscle cells in the assay described in Example 1 were performed, with percent contraction determined at 30 minutes, 5 hours, 6 hours, and/or 24 hours as indicated in FIG. 8. Unlike nifedipine and rotidrine which only exhibited efficacy at very short time scales (<5 hrs) (FIG. 7), Niclosamide, PD 173952, Tetracaine, and JW74 demonstrate efficacy up to and beyond 24 hours in the assay of the present Examples. Niclosamide for example, known to have an excellent safety profile in healthy adults, demonstrated rapid reduction of contractile tone at 30 mins, and continued to have this effect at 6hrs and 24 hrs. A smooth concentration-dependent response is observed with sub -micromolar IC50s. Thus, data presented in FIG. 8, showing demonstrates robust dose-response and long-acting effects.

[0230] The present disclosure and Examples therefore unexpectedly demonstrate that niclosamide and niclosamide analogs, and other contraction-regulatory compounds disclosed herein, are effective for treatment of preterm labor and for reduction of uterine contractions, and further demonstrate surprisingly extended duration of efficacy in USM cells as compared to other tested compounds. These results are particularly noteworthy in the context of preterm labor, a field for which FDA approved treatments are lacking despite decades of research and a high rate of occurrence. The difficulty of developing contraction-regulatory agents is at least in part due to the unique biology that drives USM cell contraction during labor and delivery, which is not found in any other cell type and limits the applicability of data from other cell types to development of contraction-regulatory compounds for use in labor and delivery. It was therefore an unexpected outcome of the present Examples that niclosamide and niclosamide analogs are potent regulators of USM cell contraction, and further still that they present superior duration of efficacy, rendering contraction-reducing agents of the present disclosure specifically and particularly advantageous for, e.g., reduction of contraction and treatment of preterm labor.

Works Cited

[0231] 1. Romero, R., Dey, S. K. & Fisher, S. J. Preterm labor: one syndrome, many causes. Science 345, 760-765 (2014).

[0232] 2. Preterm Birth: Causes, Consequences, and Prevention - PubMed - NCBI.

Available at: https://www.ncbi.nlm.nih.gov/pubmed/20669423. (Accessed: 5th September 2019)

[0233] 3. Prevention of Recurrent Preterm Delivery by 17 Alpha-Hydroxyprogesterone

Caproate | NEJM. Available at: https://www.nejm.org/doi/full/10.1056/nejmoa035140.

(Accessed: 5th September 2019)

[0234] 4. Esplin, M. S. et al. Predictive Accuracy of Serial Transvaginal Cervical

Lengths and Quantitative Vaginal Fetal Fibronectin Levels for Spontaneous Preterm Birth Among Nulliparous Women. JAMA 317, 1047-1056 (2017).

[0235] 5. Short-term tocolytics for preterm delivery - current perspectives. - PubMed -

NCBI. Available at: https://www.ncbi.nlm.nih.gov/pubmed/24707187. (Accessed: 5th

September 2019)

[0236] 6. Pushkarsky, F et al. Elastomeric sensor surfaces for high-throughput single cell force cytometry. Nat. Biomed. Eng. 2, 124-137 (2018).

[0237] 7. Metallization and biopatterning on ultra-flexible substrates via dextran sacrificial layers. - PubMed - NCBF Available at:

https://www.ncbi.nlm.nih.gov/pubmed/25153326. (Accessed: 5th September 2019)

[0238] 8. Pushkarsky, F FLECS Technology for High-Throughput Single-Cell Force

Biology and Screening. Assay Drug Dev. Technol. 16, 7-11 (2018).

[0239] 9. Koziol-White, C. J. et al. Inhibition of PI3K promotes dilation of human small airways in a rho kinase-dependent manner. Br. J. Pharmacol. 173, 2726-2738 (2016). [0240] 10. Yoo, E. J. et al. Gal2 facilitates shortening in human airway smooth muscle by modulating phosphoinositide 3 -kinase-mediated activation in a RhoA-dependent manner. Br. J. Pharmacol. 174, 4383-4395 (2017).

[0241] 11. Boyle, A. K., Rinaldi, S. F., Rossi, A. G., Saunders, P. T. K. & Norman, J.

E. Repurposing simvastatin as a therapy for preterm labor: evidence from preclinical models. FASEB J Off. Publ. Fed. Am. Soc. Exp. Biol. 33, 2743-2758 (2019).

[0242] 12. Oh, S.-J., Paick, S. H., Lim, D. J., Lee, E. & Lee, S. E. Effects of local anesthetics on human bladder contractility. Neurourol. Urodyn. 24, 288-294 (2005).

[0243] 13. NIFEDIPINE FOR THE MANAGEMENT OF PRETERM LABOR: A

SYSTEMATIC REVIEW AND METAANALYSIS. Available at:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437772/. (Accessed: 5th September 2019)

[0244] 14. McWhorter, J., Carlan, S. J., OLeary, T. D., Richichi, K. & OBrien, W. F.

Rofecoxib versus magnesium sulfate to arrest preterm labor: a randomized trial. Obstet.

Gynecol. 103, 923-930 (2004).

[0245] 15. Arrowsmith, S., Keov, P., Muttenthaler, M. & Gruber, C. W. Contractility

Measurements of Human Uterine Smooth Muscle to Aid Drug Development. JoVE J. Vis. Exp. e56639 (2018). doi: 10.3791/56639

[0246] 16. Pohl, O. et al. OBE022, an Oral and Selective Prostaglandin F2a Receptor

Antagonist as an Effective and Safe Modality for the Treatment of Preterm Labor. J.

Pharmacol. Exp. Ther. 366, 349-364 (2018).

[0247] 17. Stratford, E. W. et al. The tankyrase-specific inhibitor JW74 affects cell cycle progression and induces apoptosis and differentiation in osteosarcoma cell lines. Cancer Med. 3, 36-46 (2014).

[0248] 18. Recruitment of b-Catenin to N-Cadherin Is Necessary for Smooth Muscle

Contraction. Available at: http://www.jbc.org/content/early/2015/02/24/jbc.M114.621003. (Accessed: 5th September 2019)

[0249] 19. Drug Repurposing: The Anthelmintics Niclosamide and Nitazoxanide Are

Potent TMEM16A Antagonists That Fully Bronchodilate Airways. - PubMed - NCBI.

Available at: https://www.ncbi.nlm.nih.gov/pubmed/30837866. (Accessed: 5th September 2019) [0250] 20. Control of vascular smooth muscle function by Src-family kinases and reactive oxygen species in health and disease. Available at:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4575571/. (Accessed: 5th September 2019) [0251] 21. Garcia-Diaz, A. et al. Interferon Receptor Signaling Pathways Regulating

PD-L1 and PD-L2 Expression. Cell Rep. 19, 1189-1201 (2017).

OTHER EMBODIMENTS

[0252] While a number of embodiments are provided in the present disclosure, it will be apparent to those of skill in the art that the present disclosure and Examples may provide other embodiments that utilize or are encompassed by the compositions and methods described herein. Therefore, it will be appreciated that the scope of is to be defined by that which may be understood from the disclosure and the appended claims rather than by the specific embodiments that have been represented by way of example.

[0253] All references cited herein are hereby incorporated by reference.

Claims

CLAIMS What is claimed is:

1. A method of treating preterm labor in a subject in need thereof, the method comprising administering to the subject a contraction-reducing compound, wherein the contraction-reducing compound is selected from:

(a) niclosamide or a niclosamide analog;

(b) a compound selected from dihydroouabain, piperlongumine, stevioside, JW74, U- 73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, lanatoside C, proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159; and/or

(c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

2. A method of reducing contractions in a subject in need thereof, the method comprising administering to the subject a contraction-reducing compound, wherein the contraction-reducing compound is selected from:

(a) niclosamide or a niclosamide analog;

(c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

3. The method of claim 1 or 2, wherein the contraction-reducing compound is niclosamide.

4. The method of claim 1 or 2, wherein the contraction-reducing compound is a niclosamide analog according to Formula I.

5. The method of claim 1 or 2, wherein the contraction-reducing compound is a niclosamide analog according to any one of Formulas I-a, I-b, I-c, I-d, I-e, I-f, or I-g.

6. The method of claim 1 or 2, wherein the contraction-reducing compound is a niclosamide analog according to any one of Formulas 1-1, 1-2, 1-3, 1-4, 1-5, 1-6 , 1-7, 1-8, 1-9, or 1-10.

7. The method of claim 1 or 2, wherein the contraction-reducing compound is a niclosamide analog according to Formula IT

8. The method of claim 1 or 2, wherein the contraction-reducing compound is selected from piperlongumine, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC- 55649, gliclazide, tetracaine hydrochloride, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159.

9. The method of claim 1 or 2, wherein the contraction-reducing compound is a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

10. The method of claim 1 or 2, wherein the contraction-reducing compound is selected from dihydroouabain, stevioside, lanatoside C, and proscillaridin A.

11. The method of any one of claims 1-10, wherein the subject is a pregnant human female and has completed less than 37 weeks of pregnancy, optionally wherein the subject has completed more than 20, 21, 22, 23, 24, or 25 weeks of pregnancy.

12. The method of any one of claims 1-11, wherein the subject has experienced a first contraction and a second contraction, where the first and second contractions are no more than 10 minutes apart.

13. The method of any one of claims 1-12, wherein the treatment reduces the strength, frequency, or duration of contractions in the subject.

14. The method of claim 13, wherein the strength, frequency, or duration of contractions is measured by a tocodynometer, electronic fetal monitor, intrauterine pressure catheter (IUPC), electrical uterine myography (EUM), and/or electrohysterography.

15. The method of any one of claims 1-14, wherein the subject has completed less than 37 weeks of pregnancy and has one or more symptoms of preterm labor, wherein the symptom of preterm labor is selected from vaginal discharge, pelvic pressure, cramping, backache, nausea, vomiting, and/or diarrhea, optionally wherein the subject has completed more than 20, 21, 22, 23, 24, or 25 weeks of pregnancy.

16. The method of claim 15, wherein the treatment reduces the symptoms of preterm labor.

17. The method of any one of claims 1-16, wherein the subject has a risk factor for preterm labor, wherein the risk factor is selected from one or more of past preterm labor, past preterm delivery, infection, carrying multiple fetuses, tobacco use, substance abuse, smoking, stress, high blood pressure, preeclampsia, diabetes, a blood clotting disorder, high weight, low weight, age under 20, age over 35, lack of prenatal medical care, pregnancy by in vitro fertilization, second pregnancy within 12 months, pregnancy following a most recent prior pregnancy by more than 59 months, shortened cervix, polyhydramnios, and/or carrying a fetus with a fetal birth defect.

18. The method of any one of claims 1-17, wherein the treatment reduces the likelihood of preterm labor as compared to a reference population.

19. The method of any one of claims 1-18, wherein the treatment reduces the strength, frequency, or duration of contractions for a period of at least 6 hours.

20. The method of any one of claims 1-18, wherein the treatment reduces the strength, frequency, or duration of contractions for a period of at least 24 hours.

21. The method of any one of claims 1-18, wherein the treatment reduces the strength, frequency, or duration of contractions for a period of at least 48 hours.

22. The method of any one of claims 1-18, wherein the treatment reduces the strength, frequency, or duration of contractions for a period of at least 72 hours.

23. The method of any one of claims 1-18, wherein the treatment reduces the strength, frequency, or duration of contractions for a period of at least 96 hours.

24. The method of any one of claims 1-23, wherein the treatment delays labor for a period of at least 6 hours as compared to a reference.

25. The method of any one of claims 1-24, wherein the treatment delays labor for a period of at least 24 hours as compared to a reference.

26. The method of any one of claims 1-25, wherein the treatment delays labor for a period of at least 48 hours as compared to a reference.

27. The method of any one of claims 1-26, wherein the treatment delays labor for a period of at least 72 hours as compared to a reference.

28. The method of any one of claims 1-27, wherein the treatment delays labor for a period of at least 96 hours as compared to a reference.

29. The method of any one of claims 1-28, wherein the treatment comprises a single dose of the contraction-regulatory compound.

30. A composition comprising a contraction-reducing compound, wherein the contraction- reducing compound is selected from:

(a) niclosamide or a niclosamide analog; (b) a compound selected from dihydroouabain, piperlongumine, stevioside, JW74, U- 73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC-55649, gliclazide, tetracaine hydrochloride, lanatoside C, proscillaridin A, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159; and/or

(c) a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

31. The composition of claim 30, wherein the contraction-reducing compound is niclosamide.

32. The composition of claim 30, wherein the contraction-reducing compound is a niclosamide analog according to Formula I.

33. The composition of claim 30, wherein the contraction-reducing compound is a niclosamide analog according to any one of Formulas I-a, I-b, I-c, I-d, I-e, I-f, or I-g.

34. The composition of claim 30, wherein the contraction-reducing compound is a niclosamide analog according to any one of Formulas 1-1, 1-2, 1-3, 1-4, 1-5, 1-6 , 1-7, 1-8, 1-9, or 1-10.

35. The composition of claim 30, wherein the contraction-reducing compound is a niclosamide analog according to Formula II.

36. The composition of claim 30, wherein the contraction-reducing compound is selected from piperlongumine, JW74, U-73343, ONO-RS-082, thapsigargin, PD173952, amisulpride, AC- 55649, gliclazide, tetracaine hydrochloride, GR 127935 hydrochloride hydrate, NAN-190 hydrobromide, and/or MRS 2159.

37. The composition of claim 30, wherein the contraction-reducing compound is a cardiac glycoside according to the cardiac glycoside structure of FIG. 6.

38. The composition of claim 30, wherein the contraction-reducing compound is selected from dihydroouabain, stevioside, lanatoside C, and proscillaridin A.

39. The composition of any one of claims 30-38, wherein the composition is for treating preterm labor in a subject in need thereof or for reducing contractions in a subject in need thereof.