Megakaryocyte differentiation and maturation inhibitors

Abstract

The present invention relates to a compound represented by formula (I) that selectively inhibits the differentiation of hematopoietic stem cells into megakaryocytes. TIFF2026516237000018.tif3064

Description

[Technical Field]

[0001] The present invention relates to megakaryocyte differentiation and maturation inhibitors containing 5-methyl-6-phenyl-4,5-dihydro-2H-pyridazine-3-one derivatives. More specifically, it relates to platelet production inhibitors (e.g., agents for the treatment of essential thrombocythemia). [Background technology]

[0002] Essential thrombocythemia (also known as primary thrombocythemia) is a disease characterized by an increased platelet count, megakaryocyte hyperplasia, and a tendency toward hemorrhagic or thrombotic disorders. Symptoms and signs include muscle weakness, headache, paresthesia, bleeding, and erythromelalgia with ischemia of the fingers. The prevalence is approximately 0.48 per 100,000 people (Non-Patent Literature 1).

[0003] Non-patent document 2 classifies anagrelide, a drug used to treat essential thrombocythemia, as a phosphodiesterase 3 (PDE3) inhibitor. Unlike other PDE3 inhibitors, it inhibits megakaryocyte differentiation, suggesting that its mechanism of action may involve the interaction between PDE3A and shlafen 12 (SLFN12). However, the results of studies verifying its effects on megakaryocytes are not disclosed.

[0004] Patent Document 1 discloses a 5-methyl-6-phenyl-4,5-dihydro-2H-pyridazine-3-one derivative as a malignant tumor treatment agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] WO2017 / 150654 [Non-patent literature]

[0006] [Non-Patent Document 1] Orphanet Report Series; Prevalence and incidence of rare diseases: Bibliographic data, January 2022 (www.orhpa.net)

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a compound that selectively inhibits the differentiation of hematopoietic stem cells into megakaryocytes.

Means for Solving the Problems

[0008] As a result of repeated studies to solve the above problems, the present inventors found that the compound represented by the following formula (I) promotes the formation of a complex of PDE3A and SLFN12. In addition, it was found that the compound does not affect the differentiation of hematopoietic stem cells into erythroblasts and myeloid cells, but inhibits the differentiation into megakaryocytes, leading to the completion of the present invention.

[0009] That is, the present invention includes the following aspects. [1-1] Formula (I):

Chemical formula

[0010] , , R 2 , R 3 and R 4 are independently halogen or C 1-3 alkyl] A pharmaceutical composition for the prevention and / or treatment of symptoms and / or diseases related to enhanced induction of megakaryocyte differentiation, comprising the compound represented by or a pharmaceutically acceptable salt thereof.

[0010] [1-2] The compound represented by formula (I) is formula (Ia): [Chemical formula] The pharmaceutical composition described in [1-1], which is a compound represented by

[0011] [1-3] R 1 and R 2 are fluorine, R 3 and R 4 are methyl, the pharmaceutical composition described in [1-1] or [1-2].

[0012] [1-4] The compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one, the pharmaceutical composition described in any one of [1-1] to [1-3].

[0013] [1-5] The pharmaceutical composition described in any one of [1-1] to [1-4], wherein the symptom related to enhanced megakaryocyte differentiation induction is enhanced platelet production.

[0014] [1-6] The pharmaceutical composition described in any one of [1-1] to [1-4], wherein the disease related to enhanced megakaryocyte differentiation induction is essential thrombocythemia.

[0015] [2-1] Formula (I): [Chemical formula] [In the formula, R 1 , R 2 , R 3 and R 4 are independently halogen or C 1-3 alkyl]. Use of compounds represented by or pharmaceutically acceptable salts thereof in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation.

[0016] [2-2] The compound represented by formula (I) is formula (Ia): [ka] The use described in [2-1].

[0017] [2-3] The use described in [2-1] or [2-2], wherein the compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one.

[0018] [2-4] Use as described in any of [2-1] to [2-3], where increased platelet production is a symptom associated with enhanced megakaryocyte differentiation.

[0019] [2-5] The use described in any of [2-1] to [2-3] is for essential thrombocythemia, a disease associated with enhanced megakaryocyte differentiation induction.

[0020] [3-1] Equation for effective quantity (I): [ka] [In the formula, R 1 , R 2 , R 3 and R 4 These are, independently, halogen or C 1-3 It is alkyl. A method for preventing and / or treating symptoms and / or diseases associated with enhanced megakaryocyte differentiation, comprising administering to a subject a compound represented by or a pharmaceutically acceptable salt thereof.

[0021] [3-2] The compound represented by formula (I) is formula (Ia): [ka] The method described in [3-1], wherein the compound is represented by [3-1].

[0022] [3-3] The method according to [3-1] or [3-2], wherein the compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one.

[0023] [3-4] The method described in any of [3-1] to [3-3], wherein the symptom associated with enhanced megakaryocyte differentiation is increased platelet production.

[0024] [3-5] The method described in any of [3-1] to [3-3], wherein the disease associated with enhanced megakaryocyte differentiation is essential thrombocythemia.

[0025] [4-1] Formula (I): For use in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation: [ka] [In the formula, R 1 , R 2 , R 3 and R 4 These are, independently, halogen or C 1-3 It is alkyl. A compound represented by or a pharmaceutically acceptable salt thereof.

[0026] [4-2] The compound represented by formula (I) is formula (Ia): [ka] The compound described in [4-1] or a pharmaceutically acceptable salt thereof.

[0027] [4-3] The compound described in [4-1] or [4-2] or a pharmaceutically acceptable salt thereof, wherein the compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one.

[0028] [4-4] A compound described in any of [4-1] to [4-3], or a pharmaceutically acceptable salt thereof, wherein the symptom associated with enhanced megakaryocyte differentiation is increased platelet production.

[0029] [4-5] Essential thrombocythemia is a disease associated with enhanced megakaryocyte differentiation, and is one of the compounds described in any of [4-1] to [4-3] or a pharmaceutically acceptable salt thereof.

[0030] [5-1] Formula (I): In the manufacture of a pharmaceutical product for use in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation: [ka] [In the formula, R 1 , R 2 , R 3 and R 4 These are, independently, halogen or C 1-3 It is alkyl. The use of a compound represented by or a pharmaceutically acceptable salt thereof.

[0031] [5-2] The compound represented by formula (I) is formula (Ia): [ka] The use described in [5-1].

[0032] [5-3] The use described in [5-1] or [5-2], wherein the compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one.

[0033] [5-4] Use as described in any of [5-1] to [5-3], where increased platelet production is a symptom associated with enhanced megakaryocyte differentiation.

[0034] [5-5] The use described in any of [5-1] to [5-3] is for essential thrombocythemia, a disease associated with enhanced megakaryocyte differentiation induction. [Effects of the Invention]

[0035] The compounds of the present invention or their pharmaceutically acceptable salts can selectively inhibit the induction of megakaryocyte differentiation from hematopoietic stem cells, and therefore are expected to have therapeutic and / or prophylactic effects on thrombocytosis, such as essential thrombocythemia. [Brief explanation of the drawing]

[0036] [Figure 1] Figure 1 shows the electrophoretic results illustrating the complex formation of PDE3A and SLFN12 in Example 1. [Figure 2] Figure 2 shows the electrophoresis results indicating an increase in SLFN12 protein in Example 2. [Figure 3] Figure 3 is a graph showing the differentiation-inducing effect on megakaryocyte cells in Example 3. [Figure 4] Figure 4 is a graph showing the differentiation-inducing effect on erythroid cells in Example 4. [Figure 5] Figure 5 is a graph showing the differentiation-inducing effect on myeloid cells in Example 5. [Modes for carrying out the invention]

[0037] The terms and phrases used in this specification are described in detail below.

[0038] In this specification, "halogen" refers to fluorine, chlorine, bromine, or iodine. Preferably, it is fluorine, chlorine, or bromine, more preferably fluorine or chlorine, and even more preferably fluorine.

[0039] In this specification, "C 1-3 "Alkyl" refers to a group with 1 to 3 carbon atoms (C 1-3 ) is a linear or branched alkyl group, and specific examples include methyl, ethyl, n-propyl, and isopropyl, with methyl being preferred.

[0040] In this specification, “subjects” refers to vertebrates, specifically mammals, reptiles, and birds. Examples of mammals include humans, companion animals (e.g., dogs and cats), or domestic animals (e.g., cattle, horses, pigs, and sheep), with humans being preferred.

[0041] In this specification, each substituent in the compound represented by general formula (I) (hereinafter referred to as "compound (I)") is described below.

[0042] In compound (I), R 1 , R 2 , R 3 and R 4 These are, independently, halogen or C 1-3 It is alkyl, preferably fluorine or methyl. Also, R 1 and R 2 R is a halogen, preferably fluorine.3 and R 4 C 1-3 It is alkyl, preferably methyl.

[0043] The specific aspects of compound (I) are 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one

[0044] A specific embodiment of compound (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one.

[0045] The specific embodiment of compound (I) is (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one.

[0046] Compound (I) of the present invention includes pharmaceutically acceptable salt forms thereof, and depending on the type of acid addition salt or substituent, it may also form a salt with a base. Examples of such "acids" include inorganic acids (e.g., hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, etc.) and organic acids (e.g., methanesulfonic acid, p-toluenesulfonic acid, acetic acid, citric acid, tartaric acid, maleic acid, fumaric acid, malic acid, lactic acid, etc.). Examples of such "bases" include inorganic bases (e.g., sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, etc.) and organic bases (e.g., methylamine, diethylamine, trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, tris(hydroxymethyl)methylamine, dicyclohexylamine, N,N'-dibenzylethylenediamine, guanidine, pyridine, picoline, choline, etc.) and ammonium salts, etc. Furthermore, it may form salts with amino acids such as lysine, arginine, aspartic acid, and glutamic acid.

[0047] The compound (I) of the present invention also includes various hydrates, solvates, and crystalline polymorphs of compound (I) and its salts.

[0048] Compound (I) of the present invention may be a cocrystal or a cocrystalline salt. Here, a cocrystal or cocrystalline salt means a crystalline substance composed of two or more unique solids at room temperature, each having different physical properties (e.g., structure, melting point, heat of fusion, etc.). Cocrystals and cocrystalline salts can be produced by applying known cocrystallization methods.

[0049] Compound (I) of the present invention is a known compound and can be produced, for example, by the method described in WO2017 / 150654.

[0050] A pharmaceutical composition containing compound (I) of the present invention as an active ingredient will be described.

[0051] The above-mentioned pharmaceutical composition is a formulation of compound (I) of the present invention in the form of a conventional pharmaceutical composition, and is prepared using carriers, diluents and / or excipients such as commonly used fillers, bulking agents, binders, humectants, disintegrants, surfactants, lubricants, etc. (collectively referred to herein as "pharmaceutically acceptable carriers").

[0052] Such pharmaceutical compositions can be selected from various forms depending on the therapeutic purpose, and typical examples include tablets, pills, powders, liquids, suspensions, emulsions, granules, capsules, suppositories, and injections (liquids, suspensions, etc.).

[0053] When forming oral preparations, such as tablets, a wide range of known carriers can be used, including excipients such as lactose, sucrose, sodium chloride, glucose, urea, starch, calcium carbonate, kaolin, and crystalline cellulose; binders such as water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin solution, carboxymethylcellulose, shellac, methylcellulose, potassium phosphate, and polyvinylpyrrolidone; and dried starch, sodium alginate, agar powder, laminaran powder, and carbonated water. Examples of disintegrants include sodium ammonium compounds, calcium carbonate, polyoxyethylene sorbitan fatty acid esters, sodium lauryl sulfate, monoglyceride stearate, starch, lactose, etc.; disintegration inhibitors such as sucrose, stearin, cocoa butter, hydrogenated oil, etc.; absorption enhancers such as quaternary ammonium bases, sodium lauryl sulfate, etc.; humectants such as glycerin, starch, etc.; adsorbents such as starch, lactose, kaolin, bentonite, colloidal silicic acid, etc.; and lubricants such as refined talc, stearate, boric acid powder, polyethylene glycol, etc. Furthermore, fragrances, flavorings, sweeteners, etc. may be included as needed.

[0054] Furthermore, the tablets may be coated with a conventional coating material as needed, for example, sugar-coated tablets, gelatin-coated tablets, enteric-coated tablets, film-coated tablets, or double-coated or multi-layered tablets.

[0055] A wide range of known carriers can be used when forming the product into pill form. Examples include excipients such as glucose, lactose, starch, cocoa butter, hydrogenated vegetable oil, kaolin, and talc; binders such as gum arabic powder, tragacanth powder, gelatin, and ethanol; and disintegrants such as laminaran and agar.

[0056] A wide range of known carriers can be used when forming the suppository, such as polyethylene glycol, cocoa butter, higher alcohols, esters of higher alcohols, gelatin, and semi-synthetic glycerides.

[0057] When prepared as an injectable preparation, the liquid, emulsion, and suspension preparations are preferably sterilized and isotonic with blood. A wide range of known diluents can be used when forming these liquid, emulsion, and suspension preparations, including, for example, water, ethanol, propylene glycol, ethoxylated isostearyl alcohol, polyoxylated isostearyl alcohol, and polyoxyethylene sorbetane fatty acid esters. In this case, a sufficient amount of sodium chloride, glucose, or glycerin to prepare an isotonic solution may be included in the pharmaceutical preparation, and conventional solubilizers, buffers, analgesics, and, if necessary, colorants, preservatives, and / or other pharmaceuticals may also be included.

[0058] The amount of compound (I) of the present invention or a pharmaceutically acceptable salt thereof contained in the pharmaceutical composition is not particularly limited and can be appropriately selected from a wide range, but it is generally preferable to contain compound (I) of the present invention or a salt thereof in an amount of about 1 to 70% by weight in the pharmaceutical composition.

[0059] There are no particular limitations on the method of administering the pharmaceutical composition according to the present invention, and it may be administered in a manner appropriate to the various formulation forms, the age, sex, disease state, and other conditions of the target or patient (especially humans). For example, tablets, pills, liquids, suspensions, emulsions, granules, and capsules are administered orally. In the case of injections, they may be administered intravenously alone or mixed with conventional infusion fluids such as glucose and amino acids, or, if necessary, alone, intramuscularly, intradermally, subcutaneously, or intraperitoneally. In the case of suppositories, they are administered rectally.

[0060] The dosage of the above pharmaceutical composition may be appropriately selected depending on the method of use, target, or the age, sex, severity of the disease, and other conditions of the patient (especially a human). Typically, it is administered at a dose of approximately 0.001 to 100 mg per kg of body weight per day, preferably 0.001 to 50 mg, in one to several divided doses.

[0061] The above dosages vary depending on various conditions; therefore, a lower dosage may be sufficient in some cases, while a dosage exceeding the above range may be necessary in others.

[0062] Examples of dosages for the above-mentioned pharmaceutical composition include, but are not limited to, 0.15 mg, 0.3 mg, 0.6 mg, 1 mg, 2 mg, 4 mg, or 6 mg per dose.

[0063] Examples of the number of times the above pharmaceutical composition can be administered include twice a day, once a day, once every two days, once every three days, once every four days, once every five days, once every six days, once a week, or once every two weeks, or a combination of these. As an example of a combination administration, one dose may be administered on the first day, followed by one dose daily for five consecutive days starting one week later.

[0064] Compound (I) of the present invention or a pharmaceutically acceptable salt thereof selectively inhibits the differentiation of hematopoietic stem cells into megakaryocytes. Compound (I) of the present invention or a pharmaceutically acceptable salt thereof is effective in the prevention and / or treatment of thrombocytopenia, specifically essential thrombocythemia.

[0065] All patent and non-patent document disclosures cited herein are incorporated herein by reference as a whole. [Examples]

[0066] The present invention will be further described in detail by the following embodiments, which are not intended to limit the invention and may be modified without departing from the scope of the invention.

[0067] The test substance used was (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one (compound 1).

[0068] Example 1. Composite formation of PDE3A and SLFN12 To investigate the complex formation between PDE3A and SLFN12 by compound 1, a binding confirmation experiment was performed using immunoprecipitation. PFSK-1 and HeLa cell lines expressing PDE3A and SLFN12 were treated with compound 1 (1 μmol / L) for 16 hours, and immunoprecipitation was performed using an anti-PDE3A antibody. As shown in Figure 1, co-precipitation of SLFN12 was confirmed.

[0069] Example 2. Increase in SLFN12 protein Western blot analysis was performed to investigate the effect of compound 1 on the SLFN12 protein. PFSK-1, HeLa, or U-87 MG cell lines were treated with compound 1 (1 μmol / L) for 16 hours, and the SLFN12 protein was detected. The results are shown in Figure 2. In PFSK-1 and HeLa, which highly express PDE3A, treatment with compound 1 resulted in an increase in SLFN12 protein compared to untreated cells. On the other hand, in U-87 MG, which hardly expresses PDE3A, no significant compound 1-dependent increase in SLFN12 protein was observed.

[0070] Example 3. Megakaryocyte differentiation inhibitory effect We investigated whether compound 1 inhibits the differentiation of CD34-positive cells into megakaryocytes. Bone marrow-derived CD34-positive cells were cultured for 10 days in megakaryocyte differentiation medium (HemaTox® Megakaryocyte Kit, STEMCELL® Technologies) in the presence and absence of compound 1, according to the kit instructions. The number of CD41-positive megakaryocytes was measured by flow cytometry, and the viability was calculated relative to the untreated cell group. The test was performed three times using CD34-positive cells from different donors, and the viability was determined with the control group set at 100%. The results are shown in Figure 3. Compound 1 significantly reduced the number of CD41-positive megakaryocytes at concentrations of 3 nmol / L or higher. Furthermore, at a 50% inhibitory concentration (IC), 50 The concentration was 17.0 nmol / L (95% confidence interval: 10.3 - 23.7 nmol / L).

[0071] Example 4. Effect of Compound 1 on differentiation into erythroid cells We investigated whether compound 1 inhibits the differentiation of CD34-positive cells into erythroids. Bone marrow-derived CD34-positive cells were cultured for 7 days in erythroid differentiation medium (HemaTox® Erythroid Kit, STEMCELL® Technologies) according to the kit instructions. The number of CD71-positive and CD235-positive erythroids was measured by flow cytometry, and the survival rate was calculated relative to the untreated cell group. The test was performed twice using CD34-positive cells from different donors, and the survival rate was determined with the control group set at 100%. The results are shown in Figure 4. Compound 1 did not affect the differentiation of hematopoietic stem cells into erythroblasts at concentrations of 100 nmol / L or less.

[0072] Example 5. Effect of Compound 1 on differentiation into myeloid cells We investigated whether compound 1 inhibits the differentiation of CD34-positive cells into myeloid cells. Bone marrow-derived CD34-positive cells were cultured for 7 days in myeloid differentiation medium (HemaTox® Myeloid Kit, STEMCELL® Technologies) according to the kit instructions. CD13-positive and CD15-positive myeloid cells were measured by flow cytometry, and their viability was calculated relative to the untreated cell group. The test was performed twice using CD34-positive cells from different donors, and the viability was determined with the control group set at 100%. The results are shown in Figure 5. Compound 1 inhibited differentiation from hematopoietic stem cells to myeloid cells at 30 nmol / L, but no significant difference was observed at 100 nmol / L, indicating that it did not exhibit a concentration-dependent inhibitory effect on differentiation. [Industrial applicability]

[0073] The compounds of the present invention or their pharmaceutically acceptable salts inhibit the differentiation of hematopoietic stem cells into megakaryocytes, and can therefore be used for the prevention and / or treatment of thrombocytosis, such as essential thrombocythemia.

Claims

1. Equation (I): 【Chemistry 1】 [In the formula, R １ , R ２ , R ３ and R ４ These are, independently, halogen or C １－３ It is alkyl. A pharmaceutical composition for the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation, comprising a compound represented by or a pharmaceutically acceptable salt thereof.

2. The compound represented by formula (I) is formula (Ia): 【Chemistry 2】 The pharmaceutical composition according to claim 1, wherein the compound is represented by [the compound].

3. R １ and R ２ are fluorine, R ３ and R ４ and R are methyl, the pharmaceutical composition according to claim 1.

4. The pharmaceutical composition according to claim 1, wherein the compound represented by formula (I) is 6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one or (R)-6-(2,3-difluoro-4-(2-hydroxy-2-methylpropoxy)phenyl)-5-methyl-4,5-dihydropyridazin-3(2H)-one.

5. A pharmaceutical composition according to any one of claims 1 to 4, wherein the symptom associated with enhanced megakaryocyte differentiation is increased platelet production.

6. The pharmaceutical composition according to any one of claims 1 to 4, wherein the disease associated with enhanced megakaryocyte differentiation is essential thrombocythemia.

7. Equation (I): 【Transformation 3】 [In the formula, R １ , R ２ , R ３ and R ４ These are, independently, halogen or C １－３ It is alkyl. Use of the compound represented by or a pharmaceutically acceptable salt thereof in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation.

8. Equation for effective quantity (I): 【Chemistry 4】 [In the formula, R １ , R ２ , R ３ and R ４ These are, independently, halogen or C １－３ It is alkyl. A method for preventing and / or treating symptoms and / or diseases associated with enhanced megakaryocyte differentiation, comprising administering to a subject a compound represented by or a pharmaceutically acceptable salt thereof.

9. Formula (I): For use in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation: 【Transformation 5】 [In the formula, R １ , R ２ , R ３ and R ４ These are, independently, halogen or C １－３ It is alkyl. A compound represented by or a pharmaceutically acceptable salt thereof.

10. Formula (I) in the manufacture of a pharmaceutical product for use in the prevention and / or treatment of symptoms and / or diseases associated with enhanced megakaryocyte differentiation: 【Transformation 6】 [In the formula, R １ , R ２ , R ３ and R ４ These are, independently, halogen or C １－３ It is alkyl. The use of a compound represented by or a pharmaceutically acceptable salt thereof.

Images