Methotrexate (MTX) is the most used drug for the treatment of rheumatoid arthritis (RA) although outcome differs among patients.
To evaluate whether polymorphisms in pharmacokinetic genes are associated with outcome in RA patients receiving MTX.
We analyzed 28 SNPs in SLC19A1/RFC1, ABCB1, FPGS and GGH genes.
We studied 194 RA patients receiving MTX monotherapy. Two FPGS SNPs, rs10987742 and rs10106, were associated with response (p = 0.033 and p = 0.041, respectively). The FPGS rs10106 variant was also associated with MTX survival (p = 0.005) and toxicity (p = 0.021). Three ABCB1 SNPs, rs868755, rs10280623 and rs1858923, were associated with toxicity (p = 0.025, p = 0.048 and p = 0.031, respectively).
FPGS and ABCB1 genetic variants can influence the outcome in RA patients receiving MTX monotherapy.