Use of a compound of formula (I):an enantiomer thereof, a pharmaceutically acceptable salt thereof or a composition comprising any one of the same in the manufacture of a medicament for cancer maintenance therapy.本發明係關於式(I)化合物、其對映異構體、其醫藥學上可接受之鹽或包含以上任一者之組合物的用途,, 用於製造供癌症維持療法用之藥劑。