OBJECTIVETo evaluate the relationship between plasma trough level of imatinib and clinical outcomes in Chinese CML patients.

METHODSPlasma trough levels in 416 CML patients who received imatinib orally in six general hospitals were assessed. The correlations of imatinib plasma trough level with baseline characteristics including age, weight and BSA, and clinical response were evaluated.

RESULTS(1) Effects of age, body weight and BSA on imatinib plasma trough levels were not to be clinically significant. (2) Median imatinib plasma trough levels was 1271 (109-4329). Imatinib plasma trough level was related to dose of imatinib administration. Plasma trough levels at imatinib of dose < 400, 400 and > 400 mg were (969 ± 585), (1341 ± 595) and (1740 ± 748) µg/L (P < 0.01), respectively. (3) There was no statistic difference in imatinib plasma trough level with complete cytogenetic response [CCyR (1337 ± 571) µg/L vs no CCyR (1354 ± 689) µg/L, P = 0.255]. (4) Imatinib plasma trough level might be important for a good clinical response in some CML patients.

CONCLUSIONThere was a large interpatient variability in imatinib plasma concentration in Chinese CML patients. No correlation of imatinib plasma trough level with CCyR was observed. However, higher doses of imatinib were shown to attain greater trough plasma concentration, suggesting that imatinib plasma trough level might be important for a good clinical response in some CML patients.