X26 x26 11-cyclopentyl-5-methyl-2-({4-[4-(4-methylpiperazin-1-yl)piperidine-1-carbonyl]-2-[(propan-2-yl)oxy]phenyl}amino)-5,11-dihydro-6H-pyrimido[4,5-b][1,4]benzodiazepin-6-one X26