Factors Affecting Pharmacokinetic Variability of Imatinib Mesylate (Gleevec, STI-571)

Imatinib mesylate, the first tyrosine kinase inhibitor to gain approval by the FDA, remains as a pivotal example of rational drug design. Initially, imatinib was found to target the bcr-abl fusion protein in CML and further targets have subsequently been identified, including c-kit in GIST. Though a great number of studies have elucidated underlying mechanisms to explain emerging resistance to this anti-cancer agent, many cases of resistance remain unexplained. Furthermore, patients exhibit high interindividual variability in imatinib pharmacokinetics, which may contribute to suboptimal drug exposure and response