A method of treating diffuse large B-cell lymphoma comprising administering to a patient a pharmaceutically acceptable amount of a composition comprising a thienotriazolodiazepine compound, said thienotriazolodiazepine compound being represented by Formula (I), 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； &mdash；NR5&mdash；(CH2)m&mdash；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 &mdash；NR7&mdash；CO&mdash；(CH2)n&mdash；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 &mdash；(CH2)a&mdash；CO&mdash；NH&mdash；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 &mdash；(CH2)b&mdash；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, wherein the patient has activated B-cell diffuse large B-cell lymphoma.L'invention concerne un procédé de traitement du lymphome diffus à grande cellules B comprenant l'administration à un patient d'une quantité pharmaceutiquement acceptable d'une composition comprenant un composé thiénotriazolodiazépine, ledit composé thiénotriazolodiazépine étant représenté par la formula (I), dans laquelle R1 représente un groupe alkyle ayant un n
