NCIt definition : The mesylate salt form of ispinesib, a synthetic small molecule, derived from quinazolinone,
and kinesin spindle protein (KSP) inhibitor, with antineoplastic activity. Ispinesib
selectively inhibits KSP and prevents its binding to microtubules, resulting in inhibition
of mitotic spindle assembly, induction of cell cycle arrest during the M-phase, and
cell death in tumor cells that are actively dividing.;