Changes in intracellular folate metabolism during high-dose methotrexate and Leucovorin rescue therapy in children with acute lymphoblastic leukemia

Natanja Oosterom, Robert de Jonge, Desiree E. C. Smith, Rob Pieters, Wim J. E. Tissing, Marta Fiocco, Bertrand D. van Zelst, Marry M. van den Heuvel-Eibrink, Sandra G. Heil*

*Corresponding author for this work

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Abstract

Background

Methotrexate (MTX) is an important anti-folate agent in pediatric acute lymphoblastic leukemia (ALL) treatment. Folinic acid rescue therapy (Leucovorin) is administered after MTX to reduce toxicity. Previous studies hypothesized that Leucovorin could `rescue' both normal healthy cells and leukemic blasts from cell death. We assessed whether Leucovorin is able to restore red blood cell folate levels after MTX.

Methods

We prospectively determined erythrocyte folate levels (5-methyltetrahydrofolate (THF) and non-methyl THF) and serum folate levels in 67 children with ALL before start (T0) and after stop (T1) of HD-MTX and Leucovorin courses.

Results

Erythrocyte folate levels increased between T0 and T1 (mean +/- SD: 416.7 +/- 145.5 nmol/L and 641.2 +/- 196.3 nmol/L respectively, p<0.001). This was due to an increase in 5-methyl THF levels (mean increase: 217.7 +/- 209.5 nmol/L, p<0.001), whereas non-methyl THF levels did not change (median increase: 0.6 nmol/L [-9.9-11.1], p = 0.676). Serum folate levels increased between T0 and T1 (median increase: 29.2 nmol/L [32.9-74.0], p<0.001). Results were not significantly affected by age, sex, ALL immunophenotype and MTHFR c.677C> T genotype.

Conclusion

Intracellular folate levels accumulate after HD-MTX and Leucovorin therapy in children with ALL, suggesting that Leucovorin restores the intracellular folate pool. Future studies are necessary to assess concomitant lower uptake of MTX.

Original languageEnglish
Article number0221591
Number of pages13
JournalPLoS ONE
Volume14
Issue number9
DOIs
Publication statusPublished - 17-Sep-2019

Keywords

  • FOLINIC ACID
  • VITAMER DISTRIBUTION
  • PLASMA HOMOCYSTEINE
  • METHIONINE
  • ACCUMULATION
  • DEPLETION
  • 5-METHYLTETRAHYDROFOLATE
  • PHARMACOKINETICS
  • DEFICIENCY
  • INFUSIONS

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