Methotrexate (MTX) is the anchor disease-modifying antirheumatic drug (DMARD) in rheumatoid arthritis (RA) treatment. It is used in monotherapy and/or in combination with other synthetic or biological DMARDs, and is known to have the best cost-effectiveness and efficacy/toxicity ratios. However, toxicity is still a concern, with a significant proportion of patients interrupting long-term treatment due to the occurrence of MTX-related adverse drug reactions (ADRs), which are the main cause of drug withdrawal. Despite the extensive accumulated experience in the last three decades, it is still impossible in routine clinical practice to identify patients prone to develop MTX toxicity. While clinical and biological variables, including folate supplementation, partially help to minimize MTX-related ADRs, the advent of pharmacogenomics could provide further insight into risk stratification and help to optimize drug monitoring and long-term retention. In this paper, we aimed to review and summarize current data on low-dose MTX-associated toxicity, its prevention and predictors, keeping in mind practical RA clinical care.
Methotrexate (MTX) is used for rheumatoid arthritis (RA) treatment showing a wide toxicity profile. This study aimed to evaluate the influence of single nucleotide polymorphisms (SNPs) in genes encoding for MTX transporters with the occurrence of MTX-related toxicity (overall and gastrointestinal). A total of 233 Portuguese RA patients were genotyped for 23 SNPs. Haplotype analyses were performed and a toxicogenetic risk index (TRI) was created for SNPs that revealed to be statistically significant. Regarding MTX overall toxicity, an increased risk was associated to SLC19A1 rs7499 G carriers (p = 0.017), SLC46A1 rs2239907 GG (p = 0.030) and, SLCO1B1 rs4149056 T carriers (p = 0.040) and TT (p = 0.019). TRI revealed that patients with Index 3 were 18-fold more likely to present an adverse drug reaction when compared to those with Index 1 (p = 0.001). For MTX gastrointestinal toxicity, results demonstrated an increased risk associated with SLC19A1 rs7499 G carriers (p = 0.012) and GG (p = 0.045), SLC19A1 rs1051266 G carriers (p = 0.034), SLC19A1 rs2838956 A carriers (p = 0.049) and, SLCO1B1 rs4149056 T carriers (p = 0.042) and TT (p = 0.025). Haplotype analyses showed association between GGAG haplotype for SLC19A1 rs7499, rs1051266, rs2838956 and rs3788200 with MTX gastrointestinal toxicity (p = 0.029). TRI revealed that patients with Index 4 were 9-fold more likely to present a gastrointestinal disorder when compared to those with Index 1 (p = 0.020). This study demonstrated that SLC19A1, SLC46A1 and SLCO1B1 genotypes may help to identify patients with increased risk of MTX-related overall toxicity and that SLC19A1 and SLCO1B1 genotypes, and SLC19A1 haplotypes may help to identify patients with increased risk of MTX-related gastrointestinal toxicity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.