Analysis of Clinical Factors Impacting Imatinib Trough Concentrations in Chinese Patients With Gastrointestinal Stromal Tumors: A Real‐World Study

BACKGROUND: Imatinib mesylate (IM) is the first-line treatment for gastrointestinal stromal tumors (GISTs) and significantly improves patient outcomes. However, high inter-patient variability in imatinib plasma exposure leads to variable drug response. This study aimed to conduct a retrospective study to clearly assess the factors affecting the steady-state trough concentration (Css) of imatinib in Chinese patients with GIST. METHODS: of IM was analyzed for differences and correlations with body mass index (BMI), age, sex, and creatinine clearance rate (CCr). RESULTS: values compared to those with normal BMI (p < 0.05). Similarly, higher CCr values were associated with reduced IM Css (p < 0.001). Subsequent multiple linear regression analysis, adjusting for age and BMI, confirmed CCr as an independent determinant of imatinib exposure (p < 0.05). No significant differences were found between female and male patients or between elderly and non-elderly patients. CONCLUSION: CCr is an independent predictor of reduced imatinib exposure in Chinese patients with GIST. BMI, while correlated with drug concentration in initial analysis, appears to function as a significant clinical correlate whose association is substantially mediated through CCr. This highlights the importance of monitoring drug levels in patients with renal impairment to optimize dosing.