Pharmacokinetics of Temozolomide in a Patient With Glioblastoma Undergoing Hemodialysis: A Short Communication

Abstract

Background: Temozolomide (TMZ) is an alkylating agent used to treat glioblastoma. However, the pharmacokinetics of TMZ to establish a treatment strategy for patients undergoing hemodialysis (HD) remain unclear. In this case report, we evaluated the pharmacokinetics and HD removal rate of TMZ in a patient with glioblastoma undergoing HD to determine optimal dosing of TMZ. Methods: A 78-year-old man with glioblastoma who underwent HD 3 times a week was treated with TMZ concomitant with radiotherapy. One dose of TMZ was prescribed at 75 mg/m2 on the day before HD and another dose of 37.5 mg/m2 on the day before non-HD. Peak and trough concentrations (1 hour and 12 hours after dosing, respectively) were evaluated before HD and on non-HD days. HD removal rate of TMZ was calculated based on the predialyzer and postdialyzer plasma concentrations. Furthermore, the TMZ plasma concentrations were measured using liquid chromatography–tandem mass spectrometry. Results: The mean plasma peak and trough concentrations ± SD after 75 mg/m2 TMZ were 2917 ± 914 and 108 ± 17.6 ng/mL, respectively. Those after 37.5 mg/m2 TMZ dosage were 1305 ± 650 and 53.8 ± 11.8 ng/mL, respectively. The mean HD TMZ removal rate was 84.9 ± 1.9%. Conclusions: TMZ was tolerable in patients undergoing HD. Based on the data from a single individual pharmacokinetic perspective, the pharmacokinetics of TMZ in this patient undergoing HD were comparable with those observed in patients with normal renal function. In addition, it may be reasonable to administer TMZ after HD because of the high HD removal rate.