impact of high-dose methotrexate on intracellular 6-mercaptopurine disposition during interval therapy of childhood acute lymphoblastic leukemia

Purpose Low-dose methotrexate (MTX) therapy is the cornerstone treatment of acute lymphoblastic leukemia (ALL) and may enhance the activation of 6-mercaptopurine (6-MP) to 6-thioguanine nucleotides (6-TGN). Yet, data have established that high-dose MTX (HDMTX) hampers the accumulation of 6-TGN in re...

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Veröffentlicht in:Cancer chemotherapy and pharmacology 2010-09, Vol.66 (4), p.653-658
Hauptverfasser: Adam de Beaumais, T, Dervieux, T, Fakhoury, M, Medard, Y, Azougagh, S, Zhang, D, Yakouben, K, Jacqz-Aigrain, E
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Sprache:eng
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Zusammenfassung:Purpose Low-dose methotrexate (MTX) therapy is the cornerstone treatment of acute lymphoblastic leukemia (ALL) and may enhance the activation of 6-mercaptopurine (6-MP) to 6-thioguanine nucleotides (6-TGN). Yet, data have established that high-dose MTX (HDMTX) hampers the accumulation of 6-TGN in red blood cells (RBC) and lymphoblasts. Methods To clarify the pharmacokinetic interactions between these two antimetabolites, we serially measured RBC 6-TGN and MTX polyglutamates (MTXPG) levels following repeated courses of HDMTX (5 g/m² over 24 h) with daily oral 6-MP (25 mg/m²) during interval therapy in 20 children with ALL. Results HDMTX produced a rapid reduction in RBC 6-TGN 24 h after the start of MTX, and this effect was sustained at least by the third day (median decrease −21%; P < 0.001). However, a return to pre-infusion of 6-TGN levels was observed by the time of the following HDMTX course 14 days later (P < 0.001). RBC MTX polyglutamates accumulation followed Michaelis-Menten kinetics but was not associated with the change in pre-infusion 6-TGN levels which remained stable during the interval period. Conclusion HDMTX does not appear to enhance 6-MP activation to 6-TGN. Moreover, given that the deleterious effect of HDMTX on intracellular 6-MP disposition has been shown to be several folds greater in lymphoblasts than in RBC. Our data warrant additional studies elucidating the optimal MTX dose synergizing with 6-MP.
ISSN:0344-5704
1432-0843
DOI:10.1007/s00280-009-1205-4