Abstract:
A therapeutic agent for tumor for combined use of a compound or pharmaceutically acceptable salt thereof represented by Formula (I) and a compound represented by Formula (II): 
                                 
wherein R 1  is C 1-6  alkyl or C 3-8  cycloalkyl, R 2  is a hydrogen atom or C 1-6  alkoxy, and R 3  is a hydrogen atom or a halogen atom, exhibits an excellent antitumor effect compared to cases where these are individually used.

Description:
TECHNICAL FIELD 
     The present invention relates to a therapeutic agent for tumor for combined use of a compound having a kinase inhibitory effect and a compound having a BRAF inhibitory effect. Particularly, the present invention relates to a therapeutic agent for tumor for combined use of a compound having a multi-tyrosine kinase inhibitory effect and N-(3-{[5-(4-chlorophenyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]carbonyl}-2,4-difluorophenyl)propane-1-sulfonamide (PLX4032). 
     BACKGROUND ART 
                                
wherein R 1  is C 1-6  alkyl or C 3-8  cycloalkyl, R 2  is a hydrogen atom or C 1-6  alkoxy, and R 3  is a hydrogen atom or a halogen atom.
 
     The compound represented by Formula (I) has anti-angiogenic actions (Patent Literature 1), inhibitory effects (Patent Literatures 2 to 5) against tyrosine kinases which are reported to be involved in malignant alteration of tumors (Non-Patent Literatures 1 to 5), and the like; and is known as a therapeutic agent for various tumors such as thyroid cancer, lung cancer, melanoma, endometrial cancer, gastric cancer, bladder cancer, renal cancer, glioma, liver cancer, and ovarian cancer. 
     Meanwhile, N-(3-{[5-(4-chlorophenyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]carbonyl}-2,4-difluorophenyl)propane-1-sulfonamide is a compound represented by the formula (II), which is known as a potent BRAF kinase activity inhibitor (Patent Literature 6). This compound is referred to as PLX4032, which is currently under development as a therapeutic agent for tumor such as melanoma. 
     In general, therapeutic agents for tumor are often not effective for all of the patients when they were used individually. Thus, attempts have been made so far to increase the cure rate by combination of plural antitumor agents (Patent Literatures 7 to 9). 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: US Patent Application Publication No. 2004-053908 
     Patent Literature 2: US Patent Application Publication No. 2004-253205 
     Patent Literature 3: US Patent Application Publication No. 2010-105031 
     Patent Literature 4: US Patent Application Publication No. 2009-209580 
     Patent Literature 5: US Patent Application Publication No. 2009-264464 
     Patent Literature 6: WO 2007/002325 
     Patent Literature 7: WO 2009/140549 
     Patent Literature 8: US Patent Application Publication No. 2004-259834 
     Patent Literature 9: U.S. Pat. No. 6,217,866 
     Non Patent Literature 
     Non Patent Literature 1: Lasota et al., “Mutations in Exons 9 and 13 of KIT Gene Are Rare Events in Gastrointestinal Stromal Tumors”, American Journal of Pathology, vol. 157, p. 1091-1095, 2000. 
     Non Patent Literature 2: Berdel et al., “Recombinant Human Stem Cell Factor Stimulates Growth of a Human Glioblastoma Cell Line Expressing c-kit Protooncogenl”, Cancer Research, vol. 52, p. 3498-3502, 1992. 
     Non Patent Literature 3: Lennartsson et al., “The stem cell factor receptor/c-Kit as a drug target in cancer”, Current Cancer Drug Targets, vol. 6, p. 65-75, 2006. 
     Non Patent Literature 4: Turner et al., “Fibroblast growth factor signaling: from development to cancer”, Nature Reviews Cancer, vol. 10, p. 116-129, 2010. 
     Non Patent Literature 5: Wells et al, “Targeting the RET Pathway in Thyroid Cancer”, Clinical Cancer Research, vol. 15, p. 7119-7123, 2009. 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, the therapeutic effects, which have been reported so far, obtained by combination of plural therapeutic agents for tumor were insufficient, and hence development of a novel combination therapy using therapeutic agents for tumor has been expected. 
     Solution to Problem 
     In view of such circumstances, the present inventors intensively studied to discover that administration of a combination of the compound represented by Formula (I) and the compound having a kinase inhibitory effect to a patient suffering from a tumor attains an unexpectedly excellent antitumor effect, thereby completing the present invention. 
     That is, the present invention provides [1] to [8] below.
     [1] A therapeutic agent for tumor for combined use of:   

     a compound or pharmaceutically acceptable salt thereof represented by Formula (I): 
     
       
                 
         
             
             
         
      
         
         wherein R 1  is C 1-6  alkyl or C 3-8  cycloalkyl, 
         R 2  is a hydrogen atom or C 1-6  alkoxy, and 
         R 3  is a hydrogen atom or a halogen atom; and 
       
    
     a compound represented by Formula (II): 
     
       
                 
         
             
             
         
      
         
         [2] A therapeutic agent for tumor for simultaneous or separate administration of a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I), and a compound represented by the above Formula (II). 
         [3] A therapeutic agent for tumor comprising a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I), and a compound represented by the above Formula (II). 
         [4] A compound represented by the above Formula (II) for therapy of a tumor by combined use with a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I). 
         [5] A compound or pharmaceutically acceptable salt thereof represented by the above Formula (I) for therapy of a tumor by combined use with a compound represented by the above Formula (II). 
         [6] A method of treating a tumor, wherein a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I), and a compound represented by the above Formula (II) are used in combination. 
         [7] A pharmaceutical composition comprising a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I), a compound represented by the above Formula (II), and a vehicle. 
         [8] A kit comprising: a pharmaceutical composition comprising a compound or pharmaceutically acceptable salt thereof represented by the above Formula (I) and a vehicle; and a pharmaceutical composition comprising a compound represented by the above Formula (II), and a vehicle. 
       
    
     The compound represented by the above Formula (I) is preferably one or more compounds selected from the group consisting of
     4-[3-chloro-4-(cyclopropylaminocarbonyl)aminophenoxy]-7-methoxy-6-quinolinecarboxamide:   

     
       
                 
         
             
             
         
      
         
         4-[3-chloro-4-(methylaminocarbonyl)aminophenoxy]-7-methoxy-6-quinolinecarboxamide: 
       
    
     
       
                 
         
             
             
         
      
         
         4-[3-chloro-4-(ethylaminocarbonyl)aminophenoxy]-7-methoxy-6-quinolinecarboxamide: 
       
    
     
       
                 
         
             
             
         
      
         
         N6-methoxy-4-(3-chloro-4-{[(cyclopropylamino)carbonyl)amino]phenoxy}-7-methoxy-6-quinolinecarboxamide: 
       
    
     
       
                 
         
             
             
         
      
         
         and 
         N6-methoxy-4-(3-chloro-4-{[(ethylamino)carbonyl]amino}phenoxy)-7-methoxy-6-quinolinecarboxamide: 
       
    
     
       
                 
         
             
             
         
      
         
         and more preferably 
         4-[3-chloro-4-(cyclopropylaminocarbonyl)aminophenoxy]-7-methoxy-6-quinolinecarboxamide: 
       
    
     
       
                 
         
             
             
         
      
         
         (hereinafter, also sometimes expressed as Compound A). 
       
    
     Advantageous Effects of Invention 
     The present invention provides a therapeutic agent for tumor for combined use of a compound having a multi-tyrosine kinase inhibitory effect and a compound having a BRAF kinase activity inhibitory effect. Such a therapeutic agent for tumor exhibits an excellent antitumor effect compared to cases where these are individually used, and exhibits antitumor effects against various cancer types. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a graph showing a combined effect of Compound A and PLX4032 in a model animal to which human melanoma cell line (A375) was transplanted. 
         FIG. 2  is a graph showing the relative tumor volume of each group on the 23 rd  day after initiation of administration. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The compound or pharmaceutically acceptable salt thereof represented by Formula (I) according to the present invention can be produced by the method described in Patent Literature 1. Further, the compound represented by Formula (II) (hereinafter, also simply referred to as PLX4032) according to the present invention can be produced by the method described in Patent Literature 6. 
     Also, a compound known to have a BRAF inhibitory effect can be used as the therapeutic agent for tumor according to the present invention in place of PLX4032. Examples of such a compound include 4-{4-[({[4-chloro-3-(trifluoromethyl)phenyl]amino}carbonyl)amino]phenoxy}-N-methylpyridine-2-carboxamide 4-methylbenzenesulfonate (sorafenib) 
     
       
                 
         
             
             
         
      
         
         1-methyl-5-({2-[4-(trifluoromethyl)-1H-imidazol-2-yl}pyridin-4-yl]oxy)-N-[4-(trifluoromethyl)phenyl]-1H-benzimidazol-2-amine (RAF-265) 
       
    
     
       
                 
         
             
             
         
      
         
         5-(2-{4-[2-(dimethylamino)ethoxy]phenyl}-4-pyridin-4-yl-1H-imidazol-5-yl)indan-1-one oxime (SB-590885) 
       
    
     
       
                 
         
             
             
         
      
         
         1-N-(4-chlorophenyl)-6-methyl-5-N-[3-(9H-purin-6-yl)pyridin-2-yl]isoquinoline-1,5-diamine (hereinbelow, abbreviated as aminoisoquinoline) 
       
    
     
       
                 
         
             
             
         
      
         
         and [3-(3-hydroxy-5-methylphenyl)-4-(2-{[(2S)-2-hydroxypropyl]amino}pyrimidin-4-yl)-1H-pyrazol-1-yl]acetonitrile (PF-0419789) 
       
    
     
       
                 
         
             
             
         
      
     
     Sorafenib, RAF-265, SB-590885, aminoisoquinoline, and PF-0419789 can each be produced by the methods described in WO2000/041698, U.S. Patent Application Publication No. 2007-0049622, WO 2002/024680, WO 2008/153947, and WO 2007/105058, respectively. 
     Examples of the pharmaceutically acceptable salt include salts with inorganic acids, salts with organic acids, salts with inorganic bases, salts with organic bases, and salts with acidic or basic amino acids. 
     Preferred examples of the salts with inorganic acids include salts with hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like. Preferred examples of the salts with organic acids include salts with acetic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, lactic acid, stearic acid, benzoic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid and the like. 
     Preferred examples of the salts with inorganic bases include alkaline metal salts such as a sodium salt and a potassium salt; alkaline earth metal salts such as a calcium salt and a magnesium salt; an aluminum salt; and an ammonium salt. Preferred examples of the salts with organic bases include salts with diethylamine, diethanolamine, meglumine, N,N-dibenzylethylenediamine and the like. 
     Preferred examples of the salts with acidic amino acids include salts with aspartic acid, glutamic acid and the like. Preferred examples of the salts with basic amino acids include salts with arginine, lysine, ornithine and the like. 
     Especially preferred pharmaceutically acceptable salts are salts with organic acids. 
     The therapeutic agent for tumor of the present invention may be orally administered in the form of a solid formulation such as a tablet, granule, fine granule, powder or capsule, or in the form of a liquid, jelly, syrup or the like. 
     Further, the therapeutic agent for tumor of the present invention may be parenterally administered in the form of an injection, suppository, ointment, cataplasm or the like. 
     The dose of the compound or pharmaceutically acceptable salt thereof represented by Formula (I) may be appropriately selected depending on the degrees of symptoms, age, sex and body weight of the patient, difference in sensitivity, route, time and interval of administration, type of pharmaceutical formulation, and/or the like. Usually, in cases where oral administration is carried out for an adult (60 kg body weight), the dose is 1 to 600 mg, preferably 5 to 400 mg per day, more preferably 5 to 200 mg. This may be administered at one time, or dividedly at 2 or 3 times per day. 
     The dose of PLX4032 may be appropriately selected as in the case described above. Usually, in cases where oral administration is carried out for an adult (60 kg body weight), the dose is 1 to 2000 mg, preferably 100 to 1500 mg, more preferably 240 to 1200 mg per day. This may be administered at one time, or dividedly at 2 or 3 times per day. 
     In cases where an oral solid formulation is prepared, a vehicle, and, as required, a binder, disintegrant, lubricant, coloring agent, flavoring agent and/or the like may be added to the principal component, that is, a compound or pharmaceutically acceptable salt thereof represented by Formula (I), and PLX4032, to prepare, thereafter, a tablet, granule, fine granule, powder, capsule or the like according to a conventional method. 
     Examples of the vehicle include lactose, corn starch, white soft sugar, glucose, sorbitol, crystalline cellulose and silicon dioxide. Examples of the binder include polyvinyl alcohol, ethylcellulose, methylcellulose, gum Arabic, hydroxypropylcellulose and hydroxypropylmethylcellulose. Examples of the lubricant include magnesium stearate, talc and silica. Examples of the coloring agent include titanium oxide, iron sesquioxide, yellow iron sesquioxide, cochineal, carmine and riboflavin. Examples of the flavoring agent include cocoa powder, ascorbic acid, tartaric acid, peppermint oil, borneol and cinnamon powder. These tablets and granules may be coated as required. 
     In cases where an injection is prepared, a pH adjustor, buffering agent, suspending agent, solubilizer, stabilizer, isotonic agent, preservative and/or the like may be added as required to the principal component, to prepare an intravenous, subcutaneous or intramuscular injection, or an intravenous drip infusion. As required, these may be prepared into lyophilized products by conventional methods. 
     Examples of the suspending agent include methylcellulose, polysorbate 80, hydroxyethylcellulose, gum Arabic, powdered tragacanth, sodium carboxymethylcellulose and polyoxyethylene sorbitan monolaurate. 
     Examples of the solubilizer include polyoxyethylene hydrogenated castor oil, polysorbate 80, nicotinamide, polyoxyethylene sorbitan monolaurate, macrogol and glycerin fatty acid ester. 
     Examples of the stabilizer include sodium sulfite and sodium metabisulfite. Examples of the preservative include methyl parahydroxybenzoate, ethyl parahydroxybenzoate, sorbic acid, phenol, cresol and chlorocresol. 
     The therapeutic agent for tumor of the present invention may be prepared by formulating a compound or pharmaceutically acceptable salt thereof represented by Formula (I), and PLX4032 separately, and the both may be administered either at the same time or separately. Further, the two formulations may be placed in a single package, to provide the so called kit formulation. Further, the both compounds may be contained in a single formulation. 
     The type of the tumor to be treated with the therapeutic agent for tumor according to the present invention is not restricted, and examples thereof include cancers such as fibroma, adipoma, myxoma, chondroma, osteoma, angioma, hemangioendothelioma, lymphoma, myeloma, myeloid sarcoma, reticuloma, reticulosarcoma, melanoma, myoma, neuroma, glioma, neurinoma, sarcoma, osteosarcoma, myoma, fibrosarcoma, papilloma, adenoma, cystoma, brain tumor, cervical cancer, tongue cancer, pharyngeal cancer, laryngeal cancer, thyroid cancer, esophagus cancer, lung cancer, breast cancer, pancreatic cancer, gastric cancer, small intestinal cancer in duodenum, jejunum, ileum and the like, large bowel cancer in colon, caecum, rectum and the like, bladder cancer, renal cancer, liver cancer, gallbladder cancer, prostate cancer, uterine cancer, uterine cervical cancer, and ovarian cancer, mixed tumors thereof, and a metastatic tumor. 
     Industrial Applicability 
     EXAMPLES 
     The present invention is described in more detail by way of Examples below. Example 1 Tumor Proliferation Inhibitory Effect of the Combined Use of Compound A and PLX4032 on a Human Melanoma Cell Line (A375) 
     Using five nude mice in one group (CAnN.Cg-Foxn1nu/CrlCrlj, female, Charles River Laboratories Japan, Inc.), the antitumor effect of administration of Compound A, PLX4032, or both of these compounds was evaluated. The human-derived melanoma cell line A375 (ATCC) was suspended in PBS (Wako Pure Chemical Industries, Ltd) at a density of 5×10 6  cells/ml, followed by thorough mixing. The resulting mixture was subcutaneously transplanted at the right flank of the body of each mouse in an amount of 0.1 mL. Fourteen days after transplantation, the major axis and the minor axis of a tumor were measured by a digital caliper (Digimatic™ caliper, Mitsutoyo Corporation). The mice were grouped so that the average value of tumor volume was nearly equal among the groups. Also, the tumor volume was calculated according to the equations below.
 
Tumor volume (mm 3 )=major axis (mm)×minor axis (mm)×minor axis (mm)/2
 
     Compound A was dissolved in purified water at a concentration of 1 mg/mL. Also, PLX4032 was dissolved in DMSO at a concentration of 200 mg/ml. Further, the resulting solution was diluted 20-fold with a 1% aqueous solution of methylcellulose to prepare a 10 mg/mL PLX4032 suspension. 
     A control group, a Compound A group, a PLX4032 group, and a Compound A and PLX4032-combination group (hereinbelow, expressed as a combination group) were set up. The aqueous solution of Compound A or the PLX4032 suspension was orally administered to the mice in the Compound A group or the PLX4032 group, respectively, once daily at 10 mL/kg. To the combination group mice, the above drug solutions were each orally administered once daily at 10 mL/kg. The administration period was 23 days. Also, administration was not given to the control group mice. 
     The tumor volume was measured on the initial day of administration and on the 2 nd , 5 th , 7 th , 9 th , 12 th , 14 th , 16 th , 19 th , 21 st , and 23 rd  days after initiation of administration. The ratio of the tumor volume on each day of measurement relative to the tumor volume on the initial day of administration was calculated as a relative tumor volume (hereinbelow, expressed as RTV). Further, the average value of RTV of mice in each group was calculated. The changes in the average value of RTV with time were shown in Table 1 and  FIG. 1  and the value of each group on Day 23 was shown in  FIG. 2 . 
     
       
         
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                   
                 Day 2 
                 Day 5 
                 Day 7 
                 Day 9 
                 Day 12 
               
               
                   
               
               
                 Control 
                 1.80 
                 3.47 
                 5.29 
                 6.52 
                 8.77 
               
               
                 group 
               
               
                 Compound A 
                 1.77 
                 2.62 
                 3.40 
                 3.85 
                 5.12 
               
               
                 group 
               
               
                 PLX4032 
                 0.98 
                 0.94 
                 1.00 
                 1.13 
                 1.46 
               
               
                 group 
               
               
                 Combination 
                 0.90 
                 0.84 
                 0.77 
                 0.75 
                 0.78 
               
               
                 group 
               
               
                   
               
               
                   
                 Day 14 
                 Day 16 
                 Day 19 
                 Day 21 
                 Day 23 
               
               
                   
               
               
                 Control 
                 10.66 
                 11.95 
                 15.49 
                 17.29 
                 19.31 
               
               
                 group 
               
               
                 Compound A 
                 5.40 
                 6.30 
                 7.89 
                 9.16 
                 10.17 
               
               
                 group 
               
               
                 PLX4032 
                 1.38 
                 1.52 
                 1.63 
                 1.80 
                 1.93 
               
               
                 group 
               
               
                 Combination 
                 0.69 
                 0.63 
                 0.55 
                 0.56 
                 0.48 
               
               
                 group