Abstract | INTRODUCTION: METHODS: Pediatric Oncology Group (POG) 9605, a randomized, open label phase III study of standard-risk ALL, was designed to compare daily with twice-daily mercaptopurine during continuation therapy. Red blood cell (RBC) TGN and methylated mercaptopurine metabolite levels were measured as surrogates of leukemic cell levels in a randomly selected subset of patients. TGN and methylated mercaptopurine metabolites were analyzed quantitatively by high-performance liquid chromatography (HPLC) and reported in ng/8 x 10.8 RBC. Statistical inferences utilized multiple linear regression. RESULTS: One hundred eighteen patients received mercaptopurine 75 mg/m(2) daily and 108 received 37.5 mg/m(2)/dose twice daily. Descriptive statistics for the daily group showed the median TGN was 42 ng (mean and standard deviation [SD] = 48 +/- 35, quartiles 29-64). For the twice daily group, it was 40 ng (mean and SD = 40 +/- 27, quartiles 26-53). For methylated mercaptopurine metabolites, the daily group median was 2,020 ng (mean and SD = 2,278 +/- 1,559, quartiles 1,247-3,162); the twice daily group median was 1,275 ng (mean and SD = 1,580 +/- 1,240, quartiles 599-2,369). When adjusted for the covariables: actual dosage, days on study, age at diagnosis, white blood cell count, gender, Black race compared with not, and Hispanic compared with not, daily dosing resulted in significantly higher average methylated mercaptopurine metabolites by 668 (standard error [SE] = 179, P = 0.001) and a trend toward higher average TGNs by 6.2 (SE = 4.2, P = 0.14). CONCLUSIONS: Daily dosing of mercaptopurine resulted in higher mean red cell methylated mercaptopurine metabolites when compared to split (twice a day dosing). The data were inconclusive with respect to TGNs. The relationships of methylated mercaptopurine metabolites and TGNs to clinical outcomes will be elucidated as part of the maturing 9605 data.
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Authors | B A Bell, G N Brockway, J J Shuster, G Erdmann, S Sterikoff, B Bostrom, B M Camitta, Pediatric Oncology Group study (now The Children's Oncology Group) |
Journal | Pediatric blood & cancer
(Pediatr Blood Cancer)
Vol. 43
Issue 2
Pg. 105-9
(Aug 2004)
ISSN: 1545-5009 [Print] United States |
PMID | 15236274
(Publication Type: Clinical Trial, Comparative Study, Journal Article, Randomized Controlled Trial)
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Copyright | Copyright 2004 Wiley-Liss, Inc. |
Chemical References |
- Antimetabolites, Antineoplastic
- Mercaptopurine
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Topics |
- Administration, Oral
- Antimetabolites, Antineoplastic
(administration & dosage, pharmacokinetics)
- Biological Availability
- Child
- Child, Preschool
- Drug Administration Schedule
- Female
- Humans
- Male
- Mercaptopurine
(administration & dosage, analogs & derivatives, pharmacokinetics)
- Multivariate Analysis
- Precursor Cell Lymphoblastic Leukemia-Lymphoma
(drug therapy)
- Regression Analysis
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