Simple methodology for the therapeutic drug monitoring of the tyrosine kinase inhibitors dasatinib and imatinib

A simple HPLC method has been developed to measure imatinib and N-desmethylimatinib (norimatinib) in plasma or serum at concentrations attained during therapy. Adaptation of this method to LC-MS/MS also allows dasatinib assay. A small sample volume (100 L HPLC-UV, 50 L LC-MS/MS) is required and analysis time is 1 mg/L (suggested target for response) in all but one sample from patients achieving complete molecular response. As to dasatinib, the median (range) plasma dasatinib concentration was 13 (2-143) mu g/L (N=33). More observations are needed to properly assess the potential role of therapeutic drug monitoring in guiding treatment with dasatinib.