SB-743921

SB-743921 is a kinesin spindle protein inhibitor with IC50 of 0.2 nM, 0.07 nM, 1.7 nM, 0.06 nM and 14.4 nM in SKOV3, Colo205, MV522, MX1 and P388 cell lines, respectively. SB-743921 selectively inhibits kinesin spindle protein (KSP), an important protein involved in the early stages of mitosis that is expressed in proliferating cells. SB 743921 blocks assembly of a functional mitotic spindle, thereby causing cell cycle arrest in mitosis and subsequent cell death. SB-743921 has significant efficacy in a broad spectrum of tumor models differing from that of taxanes. The maximum-tolerated dose (MTD) of SB-743921 as a 1-h infusion every 21 days was established as 4 mg/m(2). SB-743921 has entered in a Phase I clinical trial in the treatment of cancer.