TY - JOUR
T1 - Myelotoxicity after high-dose methotrexate in childhood acute leukemia is influenced by 6-mercaptopurine dosing but not by intermediate thiopurine methyltransferase activity
AU - Levinsen, Mette
AU - Rosthøj, Susanne
AU - Nygaard, Ulrikka
AU - Heldrup, Jesper
AU - Harila-Saari, Arja
AU - Jonsson, Olafur G.
AU - Bechensteen, Anne Grete
AU - Abrahamsson, Jonas
AU - Lausen, Birgitte
AU - Frandsen, Thomas L.
AU - Weinshilboum, Richard M.
AU - Schmiegelow, Kjeld
N1 - Funding Information:
We acknowledge the critical input of Dr. P. D. Cole. The commitment and skillful technical assistance of Michael Timm are greatly appreciated. The study was funded by The Otto Christensens Fund, The Danish Childhood Cancer foundation, The Carl and Ellen Hertz Foundation, The Children’s Cancer Foundation of Sweden, The Danish Cancer Society, The JPC Foundation, The Lundbeck Foundation, The Minister Erna Hamilton Foundation, The Nordic Cancer Union and the US National Institutes of Health Grants R01 GM28157 and U19 GM61388.
Publisher Copyright:
© Springer-Verlag Berlin Heidelberg 2014.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Purpose: Through enhancement of 6-mercaptopurine (6MP) bioavailability and inhibition of purine de novo synthesis, high-dose methotrexate (HD-MTX) may increase incorporation into DNA of 6-thioguanine nucleotides, the cytotoxic metabolites of 6MP. Patients with intermediate activity of thiopurine methyltransferase (TPMTIA) have higher cytosol 6-thioguanine nucleotide levels. We investigated toxicity following HD-MTX during MTX/6MP maintenance therapy in relation to 6MP and TPMT. Methods: Using linear mixed models, we explored myelo-and hepatotoxicity in relation to 6MP dosage and TPMT phenotype following 1,749 HD-MTX courses to 411 children with acute lymphoblastic leukemia on maintenance therapy. Results: The degree of myelosuppression following HD-MTX was similar for patients with TPMTIA and patients with high TPMT activity (TPMTHA), when HD-MTX started with same blood counts and 6MP doses. However, since TPMTIA had lower blood counts at initiation of HD-MTX compared with TPMTHA patients (median WBC 2.8 vs. 3.3 × 109/L, P = 0.01; median ANC 1.4 vs. 1.7 × 109/L, P = 0.02), TPMTIA continued to have lower WBC and ANC levels compared with TPMTHA during all 28 days after HD-MTX [relative difference 9 % (95 % CI 2-17), P = 0.02 and 21 % (95 % CI 6-39), P = 0.005]. Still, the fractional decrease in WBC and ANC levels after HD-MTX did not differ between TPMTIA and TPMTHA patients (P = 0.47; P = 0.38). The degree of leukopenia, neutropenia, thrombocytopenia and rise in aminotransferases were all significantly related to 6MP dose (P < 0.001 for all analyses). Conclusion For both TPMTIA and TPMTHA patients, dose of 6MP prior to HD-MTX should be guided by preHD-MTX blood counts, but not by TPMT activity.
AB - Purpose: Through enhancement of 6-mercaptopurine (6MP) bioavailability and inhibition of purine de novo synthesis, high-dose methotrexate (HD-MTX) may increase incorporation into DNA of 6-thioguanine nucleotides, the cytotoxic metabolites of 6MP. Patients with intermediate activity of thiopurine methyltransferase (TPMTIA) have higher cytosol 6-thioguanine nucleotide levels. We investigated toxicity following HD-MTX during MTX/6MP maintenance therapy in relation to 6MP and TPMT. Methods: Using linear mixed models, we explored myelo-and hepatotoxicity in relation to 6MP dosage and TPMT phenotype following 1,749 HD-MTX courses to 411 children with acute lymphoblastic leukemia on maintenance therapy. Results: The degree of myelosuppression following HD-MTX was similar for patients with TPMTIA and patients with high TPMT activity (TPMTHA), when HD-MTX started with same blood counts and 6MP doses. However, since TPMTIA had lower blood counts at initiation of HD-MTX compared with TPMTHA patients (median WBC 2.8 vs. 3.3 × 109/L, P = 0.01; median ANC 1.4 vs. 1.7 × 109/L, P = 0.02), TPMTIA continued to have lower WBC and ANC levels compared with TPMTHA during all 28 days after HD-MTX [relative difference 9 % (95 % CI 2-17), P = 0.02 and 21 % (95 % CI 6-39), P = 0.005]. Still, the fractional decrease in WBC and ANC levels after HD-MTX did not differ between TPMTIA and TPMTHA patients (P = 0.47; P = 0.38). The degree of leukopenia, neutropenia, thrombocytopenia and rise in aminotransferases were all significantly related to 6MP dose (P < 0.001 for all analyses). Conclusion For both TPMTIA and TPMTHA patients, dose of 6MP prior to HD-MTX should be guided by preHD-MTX blood counts, but not by TPMT activity.
KW - Chemotherapy
KW - Oncology
KW - Pediatric
KW - Toxicity
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U2 - 10.1007/s00280-014-2613-7
DO - 10.1007/s00280-014-2613-7
M3 - Article
C2 - 25347948
AN - SCOPUS:84925230908
SN - 0344-5704
VL - 75
SP - 59
EP - 66
JO - Cancer chemotherapy and pharmacology
JF - Cancer chemotherapy and pharmacology
IS - 1
ER -