We have located links that may give you full text access.
Measures of 6-mercaptopurine and methotrexate maintenance therapy intensity in childhood acute lymphoblastic leukemia.
Cancer Chemotherapy and Pharmacology 2016 November
PURPOSE: Normal white blood cell counts (WBC) are unknown in children with acute lymphoblastic leukemia (ALL). Accordingly, 6-mercaptopurine (6MP) and methotrexate (MTX) maintenance therapy is adjusted by a common WBC target of 1.5-3.0 × 10(9)/L. Consequently, the absolute degree of myelosuppression is unknown for the individual child and we wanted to evaluate this.
METHODS: A median of 22 (range 8-27) 6MP/MTX metabolite samples and 100 (range 25-130) blood counts during therapy and 10 (range 2-15) off therapy were collected in 50 children with ALL. Differences between off-therapy and on-therapy WBCs [including absolute neutrophil (ANC) and lymphocyte counts (ALC)] were used to retrospectively approximate the absolute myelosuppression (="delta-") and association with age, sex and 6MP/MTX doses explored. We applied linear mixed models to estimate on-therapy counts by 6MP/MTX metabolites: DNA-incorporated thioguanine nucleotides (DNA-TGN), erythrocyte thioguanine nucleotides (ery-TGN), erythrocyte-methylated 6MP metabolites (ery-MeMP) and erythrocyte MTX polyglutamates with 2-6 glutamate residues (ery-MTXpg2-6).
RESULTS: On-therapy WBC was correlated with ANC and ALC (r s = 0.84 and r s = 0.33, p values <0.001), whereas ANC was weakly correlated with ALC (r s = -0.11, p < 0.001), and neither significantly correlated with age. Off-therapy ALC, but not ANC, was strongly correlated with age (r s = -0.68 and -0.18, p < 0.001 and p = 0.22). Delta-ALC decreased with increasing age (r s = -0.69, p < 0.001). Incorporation of DNA-TGN was positively associated with ery-TGN (p < 0.001), ery-MeMP (p < 0.001) and ery-MTXpg2-6 (p = 0.047). On-therapy ALC decreased with increasing DNA-TGN level (p < 0.001, model adjusted for off-therapy ALC), whereas on-therapy ANC could not be modeled reliably.
CONCLUSION: Measurements of 6MP/MTX metabolites could supplement blood counts in assessing therapy intensity, but require prospective validation.
METHODS: A median of 22 (range 8-27) 6MP/MTX metabolite samples and 100 (range 25-130) blood counts during therapy and 10 (range 2-15) off therapy were collected in 50 children with ALL. Differences between off-therapy and on-therapy WBCs [including absolute neutrophil (ANC) and lymphocyte counts (ALC)] were used to retrospectively approximate the absolute myelosuppression (="delta-") and association with age, sex and 6MP/MTX doses explored. We applied linear mixed models to estimate on-therapy counts by 6MP/MTX metabolites: DNA-incorporated thioguanine nucleotides (DNA-TGN), erythrocyte thioguanine nucleotides (ery-TGN), erythrocyte-methylated 6MP metabolites (ery-MeMP) and erythrocyte MTX polyglutamates with 2-6 glutamate residues (ery-MTXpg2-6).
RESULTS: On-therapy WBC was correlated with ANC and ALC (r s = 0.84 and r s = 0.33, p values <0.001), whereas ANC was weakly correlated with ALC (r s = -0.11, p < 0.001), and neither significantly correlated with age. Off-therapy ALC, but not ANC, was strongly correlated with age (r s = -0.68 and -0.18, p < 0.001 and p = 0.22). Delta-ALC decreased with increasing age (r s = -0.69, p < 0.001). Incorporation of DNA-TGN was positively associated with ery-TGN (p < 0.001), ery-MeMP (p < 0.001) and ery-MTXpg2-6 (p = 0.047). On-therapy ALC decreased with increasing DNA-TGN level (p < 0.001, model adjusted for off-therapy ALC), whereas on-therapy ANC could not be modeled reliably.
CONCLUSION: Measurements of 6MP/MTX metabolites could supplement blood counts in assessing therapy intensity, but require prospective validation.
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices 
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app