Bosutinib

Abstract

Bosutinib (SKI-606) is a 7-alkoxy-3-quinolinecarbonitrile, which functions as a dual inhibitor of Src and Abl kinases. In biochemical and proliferation assays, the compound was shown to be active against src family kinases and Bcr-Abl at IC50s of 100 and 90 nM, respectively. The bcr-abl fusion gene product, a consecutively activated tyrosine kinase, which is crucial for the development of chronic myeloid leukaemia (CML), is highly sensitive to bosutinib. Interestingly, distinctly lower concentrations of the dual src/abl inhibitor are required to ablate Bcr-Abl phosphorylation when compared to first-generation tyrosine kinase inhibitor imatinib (IM). Bosutinib is a potent inhibitor of CML cell proliferation in vitro and in vivo experiments and has demonstrated promising harbouring results in CML patients resistance or intolerance to IM in ongoing phase I/II clinical trials. Remarkably, bosutinib has been found to be capable of overcoming the majority of IM-resistant bcr-abl mutations. A randomised open label phase III clinical study to compare the efficacy of bosutinib and IM in first-line therapy of Ph⁺ chronic phase (CP) CML has recently been initiated. In a phase I/II clinical study with subjects suffering from advanced stages of solid tumours, long-term responses have also been reported. In conclusion, Bosutinib is a promising novel small molecule inhibitor for targeted therapy of CML and solid tumours.