Erythrocyte-incorporated 6-mercaptopurine metabolite levels are not affected by recent drug administration during maintenance therapy for childhood acute lymphoblastic leukemia

BackgroundChildhood acute lymphoblastic leukemia (ALL) maintenance therapy with oral 6-mercaptopurine (6-MP) and methotrexate prevents leukemic relapse by acting against residual lymphoblasts. Non-adherence to significantly increases ALL risk. The levels of intracellular 6-MP metabolites erythrocyte incorporated (ery-) thioguanine nucleotides (ery-TGN) methylated (ery-MeMP) can be used evaluate adherence 6-MP, however, little is known on their short-term pharmacokinetics. aim this study was assess the changes between trough at 2-hours after intake when in plasma expected have peaked.Materials methodsTen patients stable dose were prospectively included. Two blood samples collected for ery-TGN ery-MeMP analysis (before 2 hours after).ResultsThe median 173 (range 126–299) nmol/mmol hemoglobin (HGB), h level 175 120–293) HGB. For ery-MeMP, 2h-concentrations 9 239 1 278-19 645) HGB 216 215-19 519) HGB, respectively. absolute percentual change both not statistically different from 0, p = 0.28 0.06, respectively.ConclusionsIntracellular metabolites, ery-TGN, remain a dose. This data support that may patient irrespective timing intake.