NSC-639829 (BPU) is a novel, small-molecule, oral tubulin-interactive agent with potent anti-tumour activity. NSC-639829 is a potent anticancer agent that demonstrates potent antitumor activity in vitro against several cancer cell lines as well as in vivo against several tumor models, effectively inhibits in vitro tubulin polymerization. BPU inhibits tubulin polymerisation and microtubule depolymerisation by weakly binding to the colchicine site of tubulin. It also inhibits DNA polymerasea, and HL-60 leukemia cells treated with BPU accumulate in the G1-S phase of the cell cycle. BPU demonstrated in vivo activity against a wide range of human xenografts. BPU was found to be extensively metabolised to two metabolites with anti-tumour activity, desmethyl-BPU (mmBPU) and didesmethyl-BPU (aminoBPU), which showed variable but higher exposure than did parent compound.