Influence of Methotrexate Concentration and MTHFR Gene Polymorphism on Drug Metabolism in Chinese Children with Acute Lymphoblastic Leukemia

Abstract ： Aim To investigate potential relationship between serum concentration of methotrexate (MTX) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and delayed metabolism of high-dose methotrexate (HD-MTX) and adverse reactions in Chinese children with acute lymphoblastic leukemia (ALL).Methods A total of 214 children with ALL who received CCCG-ALL-2020 regimen were collected from August 2021 to December 2023. The initial dose of HD-MTX was 3 g·m-2 in low-risk group and 5 g·m-2 in medium-high risk group. The concentration of MTX after HD-MTX treatment was detected by enzyme multiplied immunoassay technique (EMIT)，and the polymorphisms of MTHFR were detected by fluorescence in situ hybridization, and the correlation between MTHFR polymorphism and concentration of MTX and MTX metabolism and adverse reaction in children with ALL was analyzed. Results In 214 children with ALL, 19.63%, 46.73% and 33.64% were CC, CT and TT types at C677T of MTHFR gene, and 75.70%, 23.36% and 0.93% were AA, AC and CC types at A1298C, respectively. All the genotypes analyzed were in Hardy⁃Weinberg equilibrium( P > 0. 05). The statistical analysis showed that the delayed metabolism rate of TT in C677T was higher than that of CT (P < 0.05), CC was higher than that of CT (P < 0.05), but there was no significant difference between CC and TT, AA and AC of A1298C.The concentration of 42h after MTX administration ≥1μmol·L-1 was used as the standard for delayed metabolism. The risk of over grade Ⅰ neutropenia with A1298C AC genotype were significantly higher than those with AA genotype (P < 0.05). There were no statistically significant differences in myelosuppression, liver function injury, acute kidney injury, mucosal injury, fever and gastrointestinal reaction among other genotypes (P > 0.05). However, high MTX concentrations at 18 h, 42h and 66 h were significantly associated with increased frequency of over grade II renal injury, gastrointestinal reactions, and hyperbilirubinemia (P < 0.05) by Mann-Whitney U test. Multivariate Logistic regression analysis showed that medium-high risk disease (OR=3.620, 95%CI 1.768-7.413, P < 0.001), age > 14 years (OR=4.099, 95%CI 1.033-16.269, P < 0.05), body mass index (BMI) > 17 (OR=1.937, 95%CI 1.007-3.723, P < 0.05) were the risk factors for delayed metabolism, and TT genotype was the risk factor for delayed metabolism compared with MTHFR C677T CT genotype (OR=0.483, 95%CI 0.24-0.975, P < 0.05), but CC genotype could not be considered to have an effect on delayed metabolism compared with TT genotype (P > 0.05). Conclusion The concentration of methotrexate and the polymorphism of MTHFR gene may be related to the delayed metabolism and adverse reactions of MTX. Disease stratification as medium-high risk, age > 14 years, BMI > 17, and MTHFR C677T may be risk factors for delayed MTX metabolism in children with ALL. Key words ：acute lymphoblastic leukaemia；methotrexate；methylenetetrahydrofolate reductase；gene polymorphism；adverse reaction Project No：2023-12M-C&T-B-106