1. A method of treating triple negative breast cancer in a subject, comprising administering to the subject a therapeutically effective amount of paclitaxel or a pharmaceutically acceptable salt thereof and a therapeutically effective amount of a CDK inhibitor selected from compounds of formula I or their pharmaceutically acceptable salts: where Ar is phenyl, which is unsubstituted or substituted with 1, 2 or 3 identical or different substituents selected from halogen selected from chlorine, bromine, fluorine or iodine； nitro, cyano, C 1-6 alkyl, trifluoromethyl, hydroxyl, 1-4C-alkoxy, carboxy, 1-4C-alkoxycarbonyl, CONH or NRR； where each R and R are independently selected from hydrogen or C-C1-6 alkyl. 2. The method of claim 1, wherein the CDK inhibitor is a compound of formula I or a pharmaceutically acceptable salt thereof, wherein the phenyl group is substituted with 1, 2, or 3 identical or different substituents selected from halogen selected from chlorine, bromine, fluorine, or iodine； C-C1-6 alkyl or trifluoromethyl. 3. The method of claim 2, wherein the CDK inhibitor is a compound of formula I or a pharmaceutically acceptable salt thereof, wherein the phenyl group is substituted with 1, 2, or 3 halogens selected from chlorine, bromine, fluorine, or iodine. The method of claim 3, wherein the CDK inhibitor is a compound of formula I or a pharmaceutically acceptable salt thereof, wherein the phenyl group is substituted with chlorine. The method of claim 4, wherein the CDK inhibitor represented by the compound of formula I is (+) - trans-2- (2-chloro-phenyl) -5,7-dihydroxy-8- (2-hydroxymethyl-1-methyl- pyrrolidin-3-yl) -chromen-4-one hydrochloride (compound A). 6. The method of claim 2, wherein the CDK inhibitor is a compound of formula I or a pharmaceutically acceptable thereof1.Способ лечения трижды негативного рака молочной железы у субъекта, включающий введение субъекту терапевтически эффективного количества паклитаксела или его фармацевтически приемлемой со
