CW069 is an allosteric inhibitor of KIFC/HSET (IC50 = 75 μM), a microtubule motor protein involved in bipolar spindle assembly and centrosome clustering. It increases the number of multipolar spindles in N1E-115 mouse neuroblastoma cells with supernumerary centrosomes when used at concentrations of 100 and 200 μM, without affecting the morphology of mitotic spindles in normal human dermal fibroblast (NHDF) cells. CW069 inhibits proliferation of N1E-115, but not NHDF, cells (IC50s = 86 and 181 μM, respectively).