European Journal of Clinical Pharmacology

, Volume 67, Issue 10, pp 993–1006

Association of genetic polymorphism in the folate metabolic pathway with methotrexate pharmacokinetics and toxicity in childhood acute lymphoblastic leukaemia and malignant lymphoma

  • Barbara Faganel Kotnik
  • Iztok Grabnar
  • Petra Bohanec Grabar
  • Vita Dolžan
  • Janez Jazbec
Pharmacogenetics

DOI: 10.1007/s00228-011-1046-z

Cite this article as:
Faganel Kotnik, B., Grabnar, I., Bohanec Grabar, P. et al. Eur J Clin Pharmacol (2011) 67: 993. doi:10.1007/s00228-011-1046-z

Abstract

Purpose

The objectives of this study were (1) to develop a population pharmacokinetic model of high-dose methotrexate (HD-MTX) in children with acute lymphoblastic leukaemia (ALL) and malignant lymphoma (ML) in order to investigate the influence of common polymorphisms in SLC19A1, MTHFR and ABCB1 on plasma levels of MTX and (2) to estimate MTX exposure in individual patients to study the association of genetic variability in the folate metabolic pathway with MTX toxicity.

Methods

The study population comprised 64 children with ALL/ML (age 1.6–16.8 years) who had received a total of 252 MTX courses (2–4 per patient). Common putative functional polymorphisms in the SLC19A1, MTHFR, MS, MTRR, TS and ABCB1 genes were analysed by PCR-based genotyping. Nonlinear mixed effects modelling was used for the pharmacokinetic analysis.

Results

The population typical value of clearance was 7.43 L/h (inter-individual variability 43.9%), central compartment volume was 16.7 L (46.6%), peripheral compartment volume was 2.6 L (63.3%) and distribution clearance was 0.0952 L/h (66.6%). MTX clearance decreased to 73.8% in patients with the MTHFR 677TT genotype. Patients homozygous for the variant MTHFR 1298A > C [odds ratio (OR) 0.14, 95% confidence interval (CI) 0.037–0.54] and SLC19A1 80A > G (OR 0.15, 95% CI 0.039-0.60) were at decreased risk for leucopenia. The TS 2R > 3R polymorphism was associated with a lower incidence of thrombocytopenia (OR 0.15, 95% CI 0.039–0.61) and mucositis (OR 0.016, 95% CI  0.0012-0.20). In contrast, the MTHFR 677TT polymorphism was associated with an increased incidence of mucositis (OR 23, 95% CI 2.1-240).

Conclusions

A population pharmacokinetic model developed in this study implies only a limited influence of genetic factors on the systemic disposition of MTX. Clearance is moderately reduced in patients with the MTHFR 677TT genotype. Genetic polymorphisms in the folate metabolic pathway and SLC19A1 were associated with HD-MTX toxicity.

Keywords

MethotrexateAcute lymphoblastic leukaemiaChildrenPharmacogeneticsPopulation pharmacokineticsToxicity

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Barbara Faganel Kotnik
    • 1
  • Iztok Grabnar
    • 2
  • Petra Bohanec Grabar
    • 3
  • Vita Dolžan
    • 3
  • Janez Jazbec
    • 1
  1. 1.Department of Oncology and Haematology, University Children’s HospitalUniversity Medical Centre LjubljanaLjubljanaSlovenia
  2. 2.Department of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy University of LjubljanaLjubljanaSlovenia
  3. 3.Institute of Biochemistry, Faculty of MedicineUniversity of LjubljanaLjubljanaSlovenia