MTHFR genotypes and toxicity to C-MTX and HDMTX
During consolidation, MTX is utilized in interim maintenance cycles, where patients receive either escalating intravenous doses (Capizzi-MTX) or high intravenous doses of MTX (HDMTX). Given the potential intolerance to MTX found with both the homozygous 677TT and compound heterozygous 677CT/1298AC genotypes, we assessed tolerance to IV MTX given through these dosing strategies. Overall, 100 patient records were available to assess maximum C-MTX dosing. Compared to control group, the homozygous 677TT group showed significantly decreased maximum dose of Capizzi with an average maximum Capizzi dose being (174 ± 89 vs. 285 ± 90 mg/m2, p<0.05) (Fig. 1A). No other group, including the compound heterozygous group met statistical significance. For HDMTX, 99 patients were documented as receiving. Compared to control group, no genotype showed significant increase or decrease in average time to clearance of HDMTX (Fig. 1B)