Compounds of several other structural families, including the quinoxaline AG1296, the bis(1H-2-indolyl)-1-methanone D-65476, the indolinones SU5416 and SU11248, the << indolocarbazoles >> PKC412 and CEP-701, and the piperazonyl quinazoline CT53518, are potent inhibitors of [[ Flt3 ]] kinase.