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)