MEDICAMENT FOR THE TREATMENT OF CHRONIC COUGH

Abstract

Provided is a pharmaceutical composition for treating chronic cough, which has substantially no side effects of taste disturbance.

A pharmaceutical composition for treating chronic cough, comprising a compound represented by Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof.

Claims

1. A pharmaceutical composition for treating chronic cough, comprising a compound represented by Formula (I): ##STR00016## or a pharmaceutically acceptable salt thereof as an active ingredient.

2. (canceled)

3. The pharmaceutical composition according to claim 1, which has substantially no side effects of taste disturbance by the administration of the pharmaceutical composition.

4-5. (canceled)

6. A method for treating chronic cough, the method comprising a step of administering an effective amount of a compound represented by Formula (I): ##STR00017## or a pharmaceutically acceptable salt thereof as an active ingredient to an individual in need of treatment of chronic cough.

7. The method of treatment according to claim 6, wherein the chronic cough is a refractory chronic cough.

8. The method of treatment according to claim 6, wherein the compound represented by Formula (I) or the pharmaceutically acceptable salt thereof has substantially no side effects of taste disturbance by the administration of the compound or salt thereof.

9. The method of treatment according to claim 6, wherein the effective amount of the active ingredient is a daily dose of 10 mg to 450 mg.

10. The method of treatment according to claim 6, which is administered once daily.

11-15. (canceled)

16. A pharmaceutical composition comprising the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof as an active ingredient, wherein taste disturbance, a side effect related to the treatment, is reduced compared to Gefapixant ##STR00018##

17-18. (canceled)

19. A pharmaceutical composition for treating chronic cough, comprising a compound or a pharmaceutically acceptable salt thereof having 200-fold or more selectivity for a human P2X.sub.3 receptor inhibitory activity over a human P2X.sub.2/3 receptor inhibitory activity, and having substantially no side effects of taste disturbance in humans.

20. The method of treatment according to claim 6, wherein the effective amount of the active ingredient is a daily dose of 50 mg to 300 mg.

21. The method of treatment according to claim 6, wherein the effective amount of the active ingredient is a daily dose of 50 mg to 150 mg.

22. The method of treatment according to claim 6, wherein the effective amount of the active ingredient is a daily dose of 150 mg to 300 mg.

23. The method of treatment according to claim 6, which is administered once daily after a meal.

24. The method of treatment according to claim 6, which is administered once daily at bedtime.

25. The method of treatment according to claim 6, wherein the cough is a 24-hour cough.

26. The method of treatment according to claim 6, wherein the cough is a daytime cough.

Description

BRIEF DESCRIPTION OF DRAWING

[0526] FIG. 1 represents a plot (largest analysis population) of the changes in daytime cough frequency (per hour) in patients with chronic cough.

MODE FOR CARRYING OUT THE INVENTION

[0527] The term “consist of” means having only components. The term “comprise” means not restricting with components and not excluding undescribed factors.

[0528] Hereinafter, the present invention will be described with reference to embodiments. Throughout the present description, an expression in the singular form should be understood as also including the concept of its plural form, unless otherwise stated. Therefore, the singular articles (for example, “a”, “an”, “the”, and the like in English) should be understood as also including the concept of their plural form, unless otherwise stated.

[0529] In addition, the terms used in the present description should be understood as being used in the meaning commonly used in the art unless otherwise stated. Therefore, unless otherwise defined, all terminology and scientific terms used in the present description have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. In case of conflict, the present description (including definitions) prevails.

[0530] The pharmaceutical composition for treating chronic cough of the present invention is characterized by being a pharmaceutical composition containing a compound represented by Formula (I):

##STR00014##

or a pharmaceutically acceptable salt thereof, as an active ingredient. In the present description, the pharmaceutical composition for treating chronic cough of the present invention is also referred to as a therapeutic agent for chronic cough.

[0531] The compound represented by Formula (I) or a pharmaceutically acceptable salt thereof used in the present invention may be a solvate thereof.

[0532] The compound represented by Formula (I) is (2S)-3-(3-[(4-Chlorophenyl)methyl]-2,6-dioxo-4-{[4-(pyridin-2-yloxy)phenyl]amino}-3,6-dihydro-1,3,5-triazin-1(2H)-yl)-2-methyl-propanoic acid, and has P2X.sub.3 and/or P2X.sub.2/3 receptor antagonist activity. In addition, the compound represented by Formula (I) includes the following tautomer.

##STR00015##

[0533] The compound represented by Formula (I) can be synthesized according to a known method, for example, the methods described in International Publication No. WO 2014/200078 and International Publication No. WO 2012/020749.

[0534] In the present description, as the “pharmaceutically acceptable salt”, examples of basic salts include alkali metal salts such as lithium salt, sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; transition metal salts such as zinc salt and iron salt; magnesium salt; ammonium salt; aliphatic amine salts such as trimethylamine salt, triethylamine salt, dicyclohexylamine salt, ethanolamine salt, diethanolamine salt, triethanolamine salt, ethylenediamine salt, meglumine salt and procaine salt; aralkylamine salts such as N,N-dibenzylethylenediamine; aromatic heterocyclic amine salts such as pyridine salt, picoline salt, quinoline salt and isoquinoline salt; quaternary ammonium salts such as tetramethylammonium salt, tetraethylammonium salt, benzyltrimethylammonium salt, benzyltriethylammonium salt, benzyltributylammonium salt, methyltrioctylammonium salt and tetrabutylammonium salt; and basic amino acid salts such as arginine salt and lysine salt. Examples of acidic salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, phosphate, carbonate, hydrogen carbonate, hydrobromate, hydroiodide and perchlorate; organic acid salts such as formate, acetate, propionate, trifluoroacetate, citrate, lactate, tartrate, oxalate, maleate, fumarate, mandelate, glutarate, malate, benzoate, phthalate and ascorbate; sulfonates such as methanesulfonate, ethanesulfonate, isethionate, benzenesulfonate and p-toluenesulfonate; and acidic amino acid salts such as aspartate and glutamate.

[0535] Solvates include organic solvates in which any number of organic solvent molecules are coordinated and hydrates in which any number of water molecules are coordinated. In the present description, the term “solvate” means a solvate of the compound represented by the above Formula (I) or a pharmaceutically acceptable salt thereof, and examples thereof include a monosolvate, a disolvate, a monohydrate and a dihydrate.

[0536] Pharmaceutically acceptable salts and solvates can be synthesized according to a known method.

[0537] In addition, as other pharmaceutical raw materials, additives such as excipients, binders, disintegrants, lubricants, sweeteners, flavoring agents, preservatives, chelating agents, antioxidants, cooling agents, coating agents, stabilizers, fluidizers, viscous agents, solubilizers, thickeners, buffers, flavors, colorants, adsorbents, wetting agents, moisture-proof agents, antistatic agents, plasticizers, antifoaming agents, surfactants, and emulsifiers may be contained. Specifically, binders (for example, corn starch, and the like), fillers (for example, lactose, microcrystalline cellulose, and the like), disintegrants (for example, sodium starch glycolate, and the like), and lubricants (for example, magnesium stearate, and the like) can be mentioned. Their contents are not limited.

[0538] The pharmaceutical composition for the treatment of chronic cough of the present invention can be prepared according to a method known to those skilled in the art. Moreover, the shape and size of the therapeutic agent are not limited. However, oral preparations are preferable, and among these, solid preparations are more preferable. Examples of dosage forms of solid preparations can include tablets (including orally fast disintegrating tablets, chewable tablets, effervescent tablets, jelly drops, and the like), lozenges, granules, pills, powders (including fine granules), and capsules (including hard capsules and soft capsules). Moreover, when preparing these, a coating treatment may be performed by a known method.

[0539] The dose of the ingredients when used as a pharmaceutical composition for the treatment of chronic cough depends on the mode of administration, patient symptoms, age, weight, gender, or other concomitant drugs (if any), and is ultimately left to the discretion of the physician. Examples includes an aspect in which a daily adult dose of 10 to 450 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0540] One embodiment includes an aspect in which a daily adult dose of 10 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0541] One embodiment includes an aspect in which a daily adult dose of 20 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0542] One embodiment includes an aspect in which a daily adult dose of 30 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0543] One embodiment includes an aspect in which a daily adult dose of 50 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0544] One embodiment includes an aspect in which a daily adult dose of 70 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0545] One embodiment includes an aspect in which a daily adult dose of 100 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0546] One embodiment includes an aspect in which a daily adult dose of 150 mg to 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0547] One embodiment includes an aspect in which a daily adult dose of 10 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0548] One embodiment includes an aspect in which a daily adult dose of 20 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0549] One embodiment includes an aspect in which a daily adult dose of 30 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0550] One embodiment includes an aspect in which a daily adult dose of 50 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0551] One embodiment includes an aspect in which a daily adult dose of 70 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0552] One embodiment includes an aspect in which a daily adult dose of 100 mg to 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0553] One embodiment includes an aspect in which a daily adult dose of, for example, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 105 mg, 110 mg, 115 mg, 120 mg, 125 mg, 130 mg, 135 mg, 140 mg, 145 mg or 150 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0554] One embodiment includes an aspect in which a daily adult dose of, for example, 150 mg, 200 mg, 250 mg or 300 mg of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof is orally administered.

[0555] The dose may be administered at once or in divided doses. For example, the above dose is administered once a day. For example, the above dose is administered in two divided doses per day. For example, the above dose is administered in three divided doses per day. For example, the above dose is administered in four divided doses per day.

[0556] In one embodiment, the symptom, condition or disease of the respiratory tract is attenuated by the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof. The respiratory disease may be selected from many conditions in which cough hypersensitivity is dominant, and can include unexplained cough, or cough associated with upper respiratory tract infection, chronic obstructive pulmonary disease (COPD), asthma, or idiopathic pulmonary fibrosis.

[0557] In one embodiment, the cough is a form of refractory cough, unexplained cough, idiopathic cough, sub-acute or chronic cough, treatment-resistant cough, idiopathic chronic cough, postviral cough, iatrogenic cough, cough associated with postnasal drip, cough associated with upper respiratory tract infection, asthma and/or COPD, cough associated with interstitial diseases, cough associated with reflux esophagitis (GERD) and/or cough or bronchitis associated with smoking. Iatrogenic cough can be induced by ACE inhibitors. In addition, the interstitial disease can be pulmonary fibrosis.

[0558] In the present description, the term “respiratory disease” includes, but is not limited to, cough hypersensitivity syndrome, chronic obstructive pulmonary disease (COPD), asthma, and bronchospasm. Examples of respiratory diseases include embodiments of refractory cough, unexplained cough, idiopathic cough, sub-acute or chronic cough, treatment-resistant cough, idiopathic chronic cough, cough associated with upper respiratory infection, postviral cough, iatrogenic cough (e.g., ACE inhibitor-induced), cough or bronchitis associated with idiopathic pulmonary fibrosis or smoking. Respiratory diseases include the urge to cough associated with any respiratory disease, for example, the urge to cough associated with chronic obstructive pulmonary disease (COPD), cough variant asthma, or interstitial lung disease, or to wheeze.

[0559] In the present description, “acute cough” is interpreted to mean a cough that lasts up to 3 weeks in duration. For example, an acute cough can be the result of an acute illness such as a cold or the flu. The acute cough can disappear when the causative factor (for example, cold or flu) is eliminated.

[0560] In the present description, “sub-acute cough” is interpreted to mean a cough that lasts for 3 to 8 weeks. A sub-acute cough follows the period during which a subject is infected with a disease (for example, cold or flu). A sub-acute cough is a cough that often remains after the causative factor has been removed. For example, sub-acute cough appears after an infection (for example, after a viral infection).

[0561] In the present description, “chronic cough” refers to a persistent or refractory cough that lasts longer than 8 weeks without any evident causative factor, and may not be associated with other respiratory diseases such as asthma or COPD.

[0562] In one embodiment, the present invention includes a method for treating the cough symptoms and urges to cough associated with respiratory diseases by administering the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof.

[0563] In one embodiment, the present invention includes a compound for using the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof in the treatment of the cough symptoms and urges to cough associated with respiratory diseases in a subject in need of treatment.

[0564] In one embodiment, the present invention includes use of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating the cough symptoms and urges to cough associated with respiratory diseases in a subject in need of treatment.

[0565] In one embodiment, the present invention includes a method of treating the chronic cough symptoms and/or urges to cough associated with respiratory diseases or diseases mediated by P2X.sub.3 and/or P2X.sub.2/3 receptor antagonists by administering the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof.

[0566] In one embodiment, the present invention includes the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of the chronic cough symptoms and/or urges to cough associated with respiratory diseases or diseases mediated by P2X.sub.3 and/or P2X.sub.2/3 receptor antagonists.

[0567] In one embodiment, the present invention includes use of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating the chronic cough symptoms and/or urges to cough associated with respiratory diseases or diseases mediated by P2X.sub.3 and/or P2X.sub.2/3 receptor antagonists.

[0568] In one embodiment, the present invention relates to a method for reducing the number of daytime or nighttime chronic coughs in idiopathic/treatment-resistant chronic cough.

[0569] In one embodiment, the present invention relates to a method for reducing the number of daytime or nighttime chronic coughs in refractory cough, unexplained cough or idiopathic cough.

[0570] In one embodiment, the present invention includes a method of treating the neuronal hypersensitivity causing chronic cough.

[0571] In one embodiment, the present invention includes a method of treating the neuronal hypersensitivity causing refractory cough, unexplained cough or idiopathic cough.

[0572] In one embodiment, the present invention includes the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for use in reducing the number of daytime or nighttime chronic coughs in idiopathic/treatment-resistant chronic cough causing chronic cough, and for treating the neuronal hypersensitivity causing chronic cough.

[0573] In one embodiment, the present invention includes the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for use in reducing the number of daytime or nighttime chronic coughs in refractory cough, unexplained cough or idiopathic cough, and for treating the neuronal hypersensitivity causing refractory cough, unexplained cough or idiopathic cough.

[0574] In one embodiment, the present invention includes use of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for reducing the number of daytime or nighttime chronic coughs in idiopathic/treatment-resistant chronic cough, and for treating the neuronal hypersensitivity causing chronic cough.

[0575] In one embodiment, the present invention includes use of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for reducing the number of daytime or nighttime coughs in refractory cough, unexplained cough or idiopathic cough, and for treating the neuronal hypersensitivity causing refractory cough, unexplained cough or idiopathic cough.

[0576] As described in the Examples below, the present invention is characterized by a class of P2X.sub.3 and/or P2X.sub.2/3 receptor antagonists for treating or alleviating cough, including chronic cough, and the urge to cough. The present invention has the advantage of addressing the root causes of cough hypersensitivity in these diseases, rather than simply suppressing the central modulation involved in symptom perception. For example, the present invention provides a method of reducing afferent nerve activity that induces an urge to persistent and inadequate cough in sensitized subjects (for example, humans).

[0577] The present invention also has the advantage of producing substantially no taste-related side effects in sensitized subjects (for example, humans).

[0578] Furthermore, the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof can be used for the treatment of not only chronic cough, but also acute and sub-acute cough.

EXAMPLES

[0579] Hereinafter, the present invention will be described based on examples. However, the present invention is not limited to these examples and the like.

Test Example 1 Phase I Clinical Trial

[0580] Thus far, two phase I studies have been completed. All studies were conducted based on Good Clinical Practice (GCP).

[0581] A summary of the clinical trials is shown in Table 1 below.

TABLE-US-00001 TABLE 1 Number of subjects (Number of cases Country administered with Clinical (Number the compound Administra- Purpose of trial Clinical trial of represented by tion clinical trial name design facilities) Target Dosage and administration Formula (I)) period (Status) Phase I Part A (Single Japan Japanese Part A: Part A: 48 (36) Part A: one day Safety Single Dose Dose): (1) healthy 3, 10, 30, 100, 300, 450 mg or Part B: 15 (15) Part B: one Tolerability and Food Single-center, adult placebo; single oral time in one Pharmacokinetics Effect Study Randomized, males administration of suspension day × 3 days (Completed) Placebo-controlled, under fasted condition Double-blind Part B: Part B [Study of 150 mg; single oral Relative administration of suspension or Bioavailability (BA) tablets (50 mg tablets) under and Effect of fasted or fed condition Food]: Single-center, Randomized, Open Label, Cross-over Phase I Single-center, Japan Japanese Japanese: 150, 300 mg; tablets 30 (24) 1 day and 14 Safety Repeat Dose Randomized, (1) and (50 mg tablets) or placebo days Tolerability Study Placebo-controlled, Caucasian Caucasian: 150 mg; tablets (50 Pharmacokinetics Double-blind healthy mg tablets) or placebo (Completed) adult males Single oral administration under fed condition, after 4 days, repeated oral administration for 14 days under fed condition

(Results)

[0582] There were no deaths, serious adverse events, or adverse events leading to discontinuation of administration in either Part A or Part B of the Phase I single dose and food effect study.

[0583] There were no deaths, serious adverse events or adverse events leading to discontinuation of administration in any of the administration groups of the Phase I repeat dose study.

[0584] No taste-related adverse events or side effects were observed in all of these studies which have been conducted.

Test Example 2 Evaluation of Human P2X.SUB.3 .Receptor Inhibitory Activity

[0585] A stably expressing cell line in which C6BU-1 cells have been transfected with human P2X.sub.3 receptor gene (GenBank accession number Y07683) was seeded on a PDL-coated 96-well microplate so as to have 8000 cells per well, then cultured in medium (7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, DMEM containing 4.0 mM glutamine) at 37° C. and in 5% carbon dioxide for 1 day. The medium was replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.37 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.5% BSA, 0.04% Pluronic F-127, pH 7.5), then incubation was carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells were washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate was filled with 40 μL of wash buffer per well. The microplate was placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX was started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I) diluted with a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic F-127, pH 7.5) to different concentrations was each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of ATP solution diluted with the dilution buffer (final concentration of 50 nM) was dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity was continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, was calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) is not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer was added instead of ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) was calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity was calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 was calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Results)

[0586] The IC.sub.50 was 0.004 μM.

Test Example 3 Evaluation of Human P2X.SUB.2/3 .Receptor Inhibitory Activity

[0587] C6BU-1 cells were seeded on a PDL-coated 96-well microplate so as to have 3000 cells per well, then cultured in medium (7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, DMEM containing 4.0 mM glutamine) at 37° C. and in 5% carbon dioxide for 1 day. C6BU-1 cells were transfected with human P2X.sub.2 receptor gene (GenBank accession number AF109387) and human P2X.sub.3 receptor gene (GenBank accession number Y07683) using the transfection reagent FuGENE6 (manufactured by Promega), and further cultured at 37° C. in 5% carbon dioxide for 1 day. The medium was replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 1% BSA, 0.08% Pluronic F-127, pH 7.5), then incubation was carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells were washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate was filled with 40 μL of wash buffer per well. The microplate is placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX was started, and 40 μL per well of a DMSO solution of the compound represented by Formula (I) diluted with a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic F-127, pH 7.5) to different concentrations was each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of α,β-methylene ATP solution diluted with the dilution buffer (final concentration of 6 μM) was dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity was continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the α,β-methylene ATP solution to the fluorescence intensity at the start of measurement, was calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) is not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer was added instead of α,β-methylene ATP as 100% inhibition, the concentration for 50% inhibition (IC.sub.50) was calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity was calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.50 was calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Results)

[0588] The IC.sub.50 was 1100 nM.

Test Example 4 Evaluation of Human P2X.SUB.3 .Receptor Inhibitory Activity in the Presence of Human Serum Albumin (HSA)

[0589] A stably expressing cell line in which C6BU-1 cells have been transfected with human P2X.sub.3 receptor gene (GenBank accession number Y07683) was seeded on a PDL-coated 96-well microplate so as to have 8000 cells per well, then cultured in medium (7.0% fetal bovine serum, 7.0% horse serum, 1% antibiotic-antimycotic mixed stock solution, DMEM containing 4.0 mM glutamine) at 37° C. and in 5% carbon dioxide for 1 day. The medium was replaced with a solution containing 4 μM of Fluo-3-AM (20 mM HEPES, 137 mM NaCl, 5.37 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.5% BSA, 0.04% Pluronic F-127, pH 7.5), then incubation was carried out at 37° C. and in 5% carbon dioxide for 1 hour. The wells were washed with wash buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, pH 7.5) and the microplate was filled with 40 μL of wash buffer per well. The microplate was placed in the high-throughput screening system FDSS 7000EX (Hamamatsu Photonics). The measurement of fluorescence intensity by FDSS 7000EX was started, and 40 μL per well of a DMSO solution of the compound of the present invention diluted to different concentrations with a solution of a dilution buffer (20 mM HEPES, 137 mM NaCl, 5.27 mM KCl, 0.9 mM MgCl.sub.2, 1.26 mM CaCl.sub.2, 5.6 mM D-glucose, 2.5 mM probenecid, 0.1% Pluronic F-127, pH 7.5) to which human serum albumin was added to a final concentration of 1%, was each dispensed by the automatic pipetting device built in the FDSS 7000EX. After 5 minutes, 50 μL of ATP solution diluted with the dilution buffer (final concentration of 50 nM) was dispensed by the automatic pipetting device built in the FDSS 7000EX, and then the measurement of the fluorescence intensity was continued for 4 minutes. From the measured fluorescence intensity values, the specific maximum fluorescence intensity, which is expressed as the ratio of the maximum fluorescence intensity value after addition of the ATP solution to the fluorescence intensity at the start of measurement, was calculated for each microplate well. With the value of the specific maximum fluorescence intensity when the compound represented by Formula (I) is not contained as 0% inhibition, and the value of the specific maximum fluorescence intensity when the dilution buffer was added instead of ATP as 100% inhibition, the concentration for 80% inhibition (IC.sub.80) was calculated to evaluate the inhibitory activity of the compound represented by Formula (I). The specific maximum fluorescence intensity was calculated using the FDSS software (Hamamatsu Photonics). The IC.sub.80 was calculated using the software Microsoft Excel (Microsoft) and XLfit (idbs).

(Results)

[0590] The IC.sub.80 was 92.4 nM (46.9 ng/mL).

Test Example 5 Predicted Effective Dose for Humans

[0591] In the Phase I single dose study, 3, 10, 30, 100, 300, and 450 mg of the compound represented by Formula (I) was administered as a single dose, and the plasma concentration of the compound represented by Formula (I) in each subject 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 10, 12, 24, 36, 48, 72, and 120 hours after administration was measured over time. As a result, the maximum concentration was observed after 0.5 to 6 hours. When the compound represented by Formula (I) is administered once daily, the minimum plasma drug concentration at steady state is assumed to be the same as or higher than the plasma concentration 24 hours after the single dose. Therefore, the plasma concentration (geometric mean) after 24 hours is shown below. The plasma concentration after 24 hours at each dose was compared to 46.9 ng/mL, the IC.sub.80 calculated in Test Example 4, which is considered as the concentration that sufficiently inhibits the P2X.sub.3 receptor. As a result, 3 mg of the plasma concentration after 24 hours was lower than IC.sub.80, but 10, 30, 100, 300, and 450 mg of the plasma concentration after 24 hours exceeded IC.sub.80. Therefore, the minimum effective dose was set to 10 mg.

(Results)

[0592]

TABLE-US-00002 TABLE 2 The plasma concentration 24 hours Dosage of the compound after administration of the compound represented by represented by Formula (I), (ng/mL), Formula (I), (mg) (geometric mean) 3 15.2 10 50.7 30 134 100 424 300 1840 450 2680

[0593] In addition, in the Phase I single dose study, no dysgeusia or any taste-related disorder was observed as an adverse event in any of the dose groups of 3, 10, 30, 100, 300, and 450 mg. Moreover, in the Phase I repeat dose study, 150 and 300 mg of the compound represented by Formula (I) was repeatedly administered once daily for 2 weeks, and no dysgeusia or any taste-related disorder was observed. Therefore, the maximum effective dose with substantially no dysgeusia was set to 450 mg.

Test Example 6 Phase II Clinical Trial

[0594] A Phase II double-blind cross-over comparative study was conducted in patients with refractory/unexplained chronic cough.

[0595] In patients with refractory/unexplained chronic cough, the placebo-adjusted change from baseline in the number of coughs per hour during daytime (7 am to 7:59 pm, which means right before 8:00 pm) after 2 weeks of administration of the compound represented by Formula (I), and its significance were evaluated. Similarly, the placebo-adjusted change from baseline in the number of coughs per hour in 24 hours after administration of the compound represented by Formula (I) and its significance were also evaluated.

[0596] The placebo-adjusted change is defined by the following equation.

[00001]$\begin{array}{cc}\mathrm{Rate}\mathrm{of}\mathrm{change}\mathrm{adjusted}\mathrm{by}\mathrm{placebo}=100\times \left[\frac{\begin{array}{c}\begin{array}{c}100+\mathrm{Rate}\mathrm{of}\mathrm{change}\mathrm{during}\\ \mathrm{administration}\mathrm{of}\mathrm{the}\mathrm{compound}\end{array}\\ \mathrm{representedd}\mathrm{by}\mathrm{Formula}\left(I\right)\left(\%\right)\end{array}}{\begin{array}{c}100+\mathrm{Rate}\mathrm{of}\mathrm{change}\mathrm{during}\\ \mathrm{administration}\mathrm{of}\mathrm{placebo}\left(\%\right)\end{array}}-1\right]\left(\%\right)& \left[\mathrm{Expression}1\right]\end{array}$

(Clinical Trial Design)

[0597] The trial was conducted as a placebo-controlled, multicenter, randomized, double-blind, cross-over comparative study. The study consists of a screening phase (1 to 4 weeks), a first treatment phase (15 days), a drug holiday (2 to 3 weeks), a second treatment phase (15 days) and a follow-up phase (1 week).

[0598] Subjects (20 females, 11 males, mean age of 50.0 years) were randomly assigned to either the group receiving the compound according to Formula (I) first or the group receiving the placebo first. The subjects in the group receiving the compound according to Formula (I) first received orally tablets containing 150 mg of the compound according to Formula (I) (50 mg, 3 tablets), and the subjects in the group receiving the placebo first received orally placebo tablets (3 tablets), from the day following the first treatment phase once daily in the morning for 2 weeks. Then, after 2 to 3 weeks of a drug holiday, during the second treatment phase, the subjects received orally the tablets which they did not receive in the first treatment phase, once daily in the morning for 2 weeks from the day following the second treatment phase.

[0599] (Results) A comparison (full analysis population) of the change in the number of coughs per hour during daytime is shown in Table 3 and FIG. 1.

TABLE-US-00003 TABLE 3 N = 31 The compound represented by Study drug Formula (I) Placebo n 31  30 Estimated rate of change (%) −54.1 −33.0 [95% CI] [−66.7, −36.8] [−51.6, −7.2] Rate of change adjusted by −31.6 — placebo (%) [95% CI] [−53.6, 0.8]  — P-value    0.0546 —
(For the number of coughs per hour during daytime in each of the first and second treatment phases, the mixed effect model was applied, with the common logarithms of the ratio to the baseline after 2 weeks of administration as the responses, the investigational drugs, the administration groups (group receiving the compound represented by Formula (I) first and group receiving the placebo first), and the phases as the fixed effects, the individuals as the random effects, and the common logarithms of the number of coughs per hour at baseline as the covariates.)

[0600] (Results) A comparison (full analysis population) of the change in the number of coughs per hour in 24 hours is shown in Table 4.

TABLE-US-00004 TABLE 4 N = 31 The compound represented by Study drug Formula (I) Placebo n 31  30  Estimated rate of change (%) −52.6 −31.4 [95% CI] [−64.7, −36.3] [−49.1, −7.4] Rate of change adjusted by −30.9 — placebo (%) [95% CI] [−51.3, −2.1]  — P-value    0.0386 —
(For the number of coughs per hour in 24 hours in each of the first and second treatment phases, the mixed effect model was applied, with the common logarithms of the ratio to the baseline after 2 weeks of administration as the responses, the investigational drugs, administration groups (group receiving the compound represented by Formula (I) first and group receiving the placebo first), and phases as the fixed effects, the individuals as the random effects, and the common logarithms of the number of coughs per hour at baseline as the covariates.)

[0601] (Results) A comparison (full analysis population) of the total change in the sum of the three domains of the Leicester Cough Questionnaire [Japanese version] is shown in Table 5.

TABLE-US-00005 TABLE 5 N = 31 The compound represented by Study drug Formula (I) Placebo n 31    31 Estimated amount of change 2.46 1.06 [95% CI] [1.51, 3.41] [0.11, 2.01] Drug differences 1.40 — [95% CI] [0.06, 2.75] — P-value  0.0415 —
(For the change from baseline in the total score of the three domains of the Leicester Cough Questionnaire [Japanese version] at the end or discontinuation of each of the first and second treatment phases, the mixed effect model was applied, with the changes from the baseline as the responses, the investigational drugs, phases, and administration groups (group receiving the compound represented by Formula (I) first and group receiving the placebo first) as the fixed effects, the individuals as the random effects, and the total scores of the three domains of the Leicester Cough Questionnaire [Japanese version] at baseline as the covariates.)

[0602] As shown in Table 3 and FIG. 1, the placebo-adjusted rate of decrease in the number of coughs per hour during daytime was 31.6%.

[0603] As shown in Table 4, the placebo-adjusted rate of decrease in the number of coughs per hour in 24 hours was 30.9%, and a significant difference was observed.

[0604] As shown in Table 5, the difference between the investigational drug groups in the total score of the three domains of the Leicester Cough Questionnaire was 1.40 points, and a significant difference was observed.

[0605] Moreover, the efficacy of the compound according to Formula (I) and the placebo can be compared based on the following evaluation indexes for the patients with refractory/unexplained chronic cough described above.

[0606] Examples of evaluation indexes include the number of coughs per hour during nighttime, the number of coughs per hour during waking hours, the number of coughs per hour during sleeping hours, the severity assessment using the Cough Visual Analog Scale (VAS), the Patient Global Impression of Change (PGIC), and the European Quality of Life Questionnaire 5-Dimension 5-Level (EQ-5D-5L).

[0607] Next, the incidence of taste-related adverse events and side effects observed in the Phase II clinical trial is shown in Table 6.

TABLE-US-00006 TABLE 6 The compound represented by Formula (I) Placebo System Organ Class [a] - N = 31 N = 31 Preferred Term n (%) (n) n (%) (n) Patients with any Treatment -  4 (12.9) (4) 1 (3.2) (1) related AEs Nervous system disorders 2 (6.5) (2) 0 (0) Dysgeusia 1 (3.2) (1) 0 (0) Hypogeusia 1 (3.2) (1) 0 (0) Gastrointestinal disorders 1 (3.2) (1) 1 (3.2) (1) Hypoaesthesia oral 1 (3.2) (1) 1 (3.2) (1) Hepatobiliary disorders 1 (3.2) (1) 0 (0) Drug-induced liver injury 1 (3.2) (1) 0 (0) Note: “Treatment-related AE” is defined as an event in which causality cannot be denied among adverse events reported after initial administration of study drugs. (n): Number of events [a] System organ class and Preferred term of MedDRA Ver. 21.0

[0608] As shown in Table 6, taste-related adverse events were observed in 2 subjects during at the administration of the compound represented by Formula (I), but both were mild. The taste-related adverse events were dysgeusia (taste change) and hypogeusia, which were observed in 3.2% and 3.2% of patients, respectively.

[0609] Here, the incidence of taste-related adverse events in Test Example 6 was examined. In this study, the compound represented by Formula (I) and the corresponding placebo were used as the investigational drugs. As the study design, a cross-over design consisting of two treatment phases was used. Each subject was assigned to either the treatment group taking 150 mg per day of the compound represented by Formula (I) during the first treatment phase and the placebo during the second treatment phase, or the treatment group taking the placebo during the first treatment phase and 150 mg per day of the compound represented by Formula (I) during the second treatment phase. The safety analysis population in this study was 31 subjects, all of whom were taking the compound represented by Formula (I) and the placebo. Among them, dysgeusia occurred in 1 subject (1/31, 3.2%) and hypogeusia occurred in another subject (1/31, 3.2%) when taking the compound represented by Formula (I). No ageusia was observed. Therefore, taste-related adverse events occurred in 2 subjects (2/31, 6.5%). No taste-related adverse events were observed when taking the placebo.

[0610] On the other hand, in the study MK-7264-012 (ClinicalTrials.gov, identification number NCT02612610), Gefapixant and the corresponding placebo were used as the investigational drugs. As the study design, a parallel-group design consisting of four treatment groups: Gefapixant 7.5 mg, 20 mg, 50 mg, and placebo was used. Each subject was assigned to take any of these twice daily. The number of subjects in the safety analysis, and the number of subjects and the incidence of taste-related adverse events in the Gefapixant 50 mg group and the placebo group are shown in Table 7. (Number of subjects and the incidence of taste-related adverse events in the Gefapixant 50 mg group and the placebo group (Reference: Non-patent Document 25))

TABLE-US-00007 TABLE 7 Gefapixant 50 mg group Placebo group Number of subjects in safety analysis 63 63 Ageusia 13 (20.6%) 1 (1.6%) Dysgeusia 30 (47.6%) 3 (4.8%) Hypogeusia 15 (23.8%) 1 (1.6%) Any of taste-related adverse events 51 (81.0%) 4 (6.3%)

[0611] Based on the above results, for the proportion of subjects who experienced any of the taste-related adverse events, the study design of each study was taken into account, and as the difference between each investigational drug and placebo, the mean of differences of incidence in the same subject between the treatments and the two-sided 95% confidence interval thereof were calculated for Test Example 6, and the difference of incidence between the Gefapixant 50 mg treatment group and the placebo treatment group and the two-sided 95% confidence interval thereof were calculated for the study MK-7264-012. The results are shown in Table 8. As can be seen in Table 8, the 95% confidence upper limit of the difference with the placebo in the incidence of any of the taste-related adverse events obtained from Test Example 6, 15.6%, was well below the 95% confidence lower limit of 63.2% obtained from the study MK-7264-012.

(Difference Between Each Investigational Drug and Placebo in the Incidence of any the Taste-Related Adverse Events)

[0612]

TABLE-US-00008 TABLE 8 Study name: Method of Difference of 95% confidence 95% confidence calculating difference incidence lower limit upper limit Test Example 6: Difference 6.5% −2.7% 15.6% between treatments * (150 mg of compound represented by Formula (I) − placebo) Study MK-7264-012: Difference 74.6% 63.2% 86.0% between treatment groups (Gefapixant 50 mg − placebo) * Defined as the mean of the difference between the value when taking the compound represented by Formula (I) and the value when taking the placebo in each subject, and the 95% confidence interval, with 1 indicating the occurrence of any of the taste-related adverse events and 0 indicating that no adverse events occurred.

[0613] From the above results, it can be expected that the incidence of any of the taste-related adverse events is extremely low with 150 mg of the compound represented by Formula (I) compared to 50 mg of Gefapixant.

[0614] In addition, the taste-related adverse events observed in Test Example 6 accounted for 6.5% (2/31) of patients, which was similar to the 6.3% (4/63) for the adverse events observed during placebo administration in the study MK-7264-012.

FORMULATION EXAMPLE

[0615] The following Formulation Examples are only exemplified and not intended to limit the scope of the invention.

(Formulation Example 1) Suspension

[0616] For example, water for injection was added to the active pharmaceutical ingredient, the compound represented by Formula (I), to prepare a suspension.

(Formulation Example 2) Tablets

[0617] For example, lactose and magnesium stearate were added as additives to the active pharmaceutical ingredient, the compound represented by Formula (I), to prepare tablets.

INDUSTRIAL APPLICABILITY

[0618] The method for treating chronic cough of the present invention and the pharmaceutical composition for the treatment used therefor is considered to exhibit an excellent therapeutic effect by administering a predetermined amount of the active ingredient, the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof, to patients with chronic cough. In addition, having substantially no taste-related side effects from the administration of the compound represented by Formula (I) or a pharmaceutically acceptable salt thereof, the treatment method and pharmaceutical composition for the treatment of the present invention can be applied extremely safely, and are also suitable for long-term administration. Therefore, they are an excellent treatment method and pharmaceutical composition for the treatment.