Antitumor drug for intermittent administration of FGFR inhibitor

A method of treating a cancer patient, the method comprising

• administering a 3,5-disubstituted benzene alkynyl compound or a salt thereof on an administration schedule consisting of at least twice a week and a dosing interval between a day of administration and the next day of administration being at least one day, the 3,5-disubstituted benzene alkynyl compound being represented by Formula (I):
• wherein R1 is the same or different, and each represents C1-C6 alkyl;
• X1 and X2 independently represent N or CH;
• Y is a group represented by Formula (A):
• wherein the divalent moiety represented by
• is a nitrogen-containing C3-C10 heterocycloalkylene group, a group represented by Formula (B):
• wherein the divalent moiety represented by
• is a C3-C10 cycloalkylene group, or a group represented by Formula (C):
• wherein the divalent moiety represented by
• is a C6-C12 arylene group;
• R2 is hydrogen, C2-C6 alkynyl, —C(═O)ORx, —C(═O)N(Rx)(Ry), hydroxy-C1-C6 alkyl, di(C1-C6 alkyl)amino-C1-C6 alkyl, or C2-C9 heteroaryl optionally having R3;
• and R3 is C1-C6 alkyl or di(C1-C6 alkyl)amino-C1-C6 alkyl;
• Z is —C(R4)═C(R5)(R6) or —C≡C—R7;
• R4, R5, and R6 are the same or different, and each represents hydrogen, halogen, C1-C6 alkyl optionally having R8, or a group represented by Formula (D):
• wherein the monovalent moiety represented by
• is a nitrogen-containing C3-C10 heterocycloalkyl group,
• R7 is hydrogen, C1-C6 alkyl, or hydroxy-C1-C6 alkyl;
• R8 is —ORx or —N(Rx)(Ry);
• R9 is C1-C6 alkyl, halogen, or —ORx;
• Rx and Ry are the same or different, and each represents hydrogen, C1-C6 alkyl, C3-C10 cycloalkyl, di(C1-C6 alkyl)amino-C1-C6 alkyl, or C1-C6 alkoxy-C1-C6 alkyl;
• l is an integer of 0 to 3;
• m is an integer of 1 to 3;
• and
• n is an integer of 0 to 2,
• wherein said 3,5-disubstituted benzene alkynyl compound is (S)-1-(3-(4-amino-3-((3,5-dimethoxyphenyl)ethynyl)1H-pyrazolo[3,4-d]pyrimidin-1-yl)pyrrolidin-1-yl)prop-2-en-1-one.