From March 2007 to December 2010, 22 patients were sequentially enrolled in this study at Peking Union Medical College Hospital (PUMCH). CSF and plasma samples were collected at the same time from each patient after at least 7 doses of gefitinib. The concentrations of gefitinib in the CSF and plasma were measured by high performance liquid chromatography coupled with tandem mass spectrometry. The clinical factors that may affect gefitinib penetration were analyzed.
The mean plasma and CSF concentrations of gefitinib were 491.8 ¡À 184.2 ng/mL and 6.2 ¡À 4.6 ng/mL, respectively, and the mean ratio of CSF-plasma concentration was 1.3 % ¡À 0.7 % . There was a good correlation between CSF and plasma gefitinib concentrations (R = 0.556, P = .006). The presence of CNS metastases was associated with increased gefitinib CSF penetration (1.46 % vs. 0.95 % ; P = .042).
The concentration of gefitinib in CSF was low, and it was significantly related to the plasma gefitinib concentration. Because of the inadequate CNS drug exposure, patients in whom the extracranial lesions were well controlled may benefit from increasing gefitinib dose for the new intracranial lesions.