9 - cis - retinoic acid - α - tocopherol esters , pharmaceutical compositions containing the same and use of the same as a medicine for the treatment of leukemia , in particular , the remission of leukemia are provided and a combined use of a 9 - cis - retinoic acid - α - tocopherol ester and either 1α , 25 - dihydroxyvitamin d 3 or 9 - cis - retinoic acid exhibits a synergistic effect in the treatment of leukemia without any side effects caused by 1α , 25 - dihydroxyvitamin d 3 or 9 - cis - retinoic acid .