A method of treating leukemia in a mammal by administering a solid dispersion comprising an amorphous thienotriazolodiazepine compound of the Formula (1) wherein R1 is alkyl having a carbon number of 1-4, R2 is a hydrogen atom； a halogen atom； or alkyl having a carbon number of 1-4 optionally substituted by a halogen atom or a hydroxyl group, R3 is a halogen atom； phenyl optionally substituted by a halogen atom, alkyl having a carbon number of 1-4, alkoxy having a carbon number of 1-4 or cyano； —NR5—(CH2)m—R6 wherein R5 is a hydrogen atom or alkyl having a carbon number of 1-4, m is an integer of 0-4, and R6 is phenyl or pyridyl optionally substituted by a halogen atom； or —NR7—CO—(CH2)n—R8 wherein R7 is a hydrogen atom or alkyl having a carbon number of 1-4, n is an integer of 0-2, and R8 is phenyl or pyridyl optionally substituted by a halogen atom, and R4 is —(CH2)a—CO—NH—R9 wherein a is an integer of 1-4, and R9 is alkyl having a carbon number of 1-4； hydroxyalkyl having a carbon number of 1-4； alkoxy having a carbon number of 1-4； or phenyl or pyridyl optionally substituted by alkyl having a carbon number of 1-4, alkoxy having a carbon number of 1-4, amino or a hydroxyl group or —(CH2)b—COOR10 wherein b is an integer of 1-4, and R10 is alkyl having a carbon number of 1-4, or a pharmaceutically acceptable salt thereof or a hydrate or solvate thereof.La présente invention concerne une méthode permettant de traiter la leucémie chez un mammifère qui consiste à administrer une dispersion solide comprenant un composé de thiénotriazolodiazépine amorphe représenté par la formule (1) : dans laquelle R1 représente un groupe alkyle ayant de 1 à 4 atomes de carbone, R2 représente un atome d'hydrogène, un atome d'halogène ou un groupe alkyle ayant de 1 à 4 atomes de carbone facultativement substitué par un atome d'halogène ou un groupe hydroxyle, R3 représente un atome d'halogène, un groupe phényle facultativement substitué par un atome d'halogène, un groupe alkyle ayant de
