Methotrexate Toxicity In Rheumatoid Arthritis Research Articles

Association Between MTHFR C677T Polymorphism and Methotrexate Treatment Outcome in Rheumatoid Arthritis Patients: A Systematic Review and Meta-Analysis.

Methotrexate (MTX) is one of the most widely used disease-modifying antirheumatic drugs for the treatment of rheumatoid arthritis (RA). However, its efficacy in RA patients is variable and unpredictable. Methylene tetrahydrofolate reductase (MTHFR) is an important enzyme in the MTX pathway and is involved in folate metabolism and DNA synthesis. Several studies have examined the association between the MTHFR C677T polymorphism and MTX toxicity and efficacy in RA, but their conclusions remain controversial. We conducted a comprehensive literature search of the PubMed, Embase, and Cochrane Library databases to identify studies reporting an association between the MTHFR C677T single nucleotide polymorphism and MTX response in RA patients. We identified 16 studies reporting MTX efficacy in 2373 RA cases, and 25 studies reporting MTX toxicity in 4063 RA cases. The pooled data analysis indicated that the MTHFR C677T polymorphism was associated with increased toxicity, but not efficacy, of MTX in RA patients. Further stratification based on ethnicity revealed an association between the MTHFR 677TT genotype and overall MTX toxicity in East Asian and Caucasian patient populations. In addition, RA patients with the MTHFR C677T polymorphism who were supplemented with folic acid displayed significantly elevated risk for MTX toxicity. Our study indicated that the MTHFR C677T polymorphism could be used as a predictor of MTX toxicity in RA patients. However, large randomized prospective studies will be required to effectively replicate and validate these findings.

Association of the ABCB1 C3435T polymorphism with responsiveness to and toxicity of DMARDs in rheumatoid arthritis : A meta-analysis.

The aim of this study was to investigate whether the C3435T polymorphism in the gene encoding multidrug resistance protein1 (ABCB1) can predict responsiveness to or toxicity of disease-modifying antirheumatic drugs (DMARDs) in patients with rheumatoid arthritis (RA). We conducted a meta-analysis of studies on the association between the ABCB1 C3435T polymorphism and nonresponsiveness to or toxicity of DMARDs in RA patients, using the PUBMED and EMBASE electronic citation databases. Subsequent inclusion/exclusion procedures were performed and then data were extracted for association analysis. A total of 14 comparison studies from 9 articles met our inclusion criteria. This final group comprised 4studies containing data on associations between the ABCB1 C3435T polymorphism and RA susceptibility, 5studies on the response to DMARDs, and 5on toxicity of DMARDs in RA patients according to ABCB1 polymorphism status. Meta-analysis revealed no association between RA susceptibility and the ABCB1 C3435T polymorphism [odds ratio (OR) for the T allele = 0.948, 95 % confidence interval (CI) 0.756-1.189, p = 0.645]. Meta-analysis showed no association between the ABCB1 C3435T T allele and a nonresponse to DMARD therapy (OR 0.952, 95 % CI 0.516-1.685, p = 0.817). Stratification by DMARD type indicated no association between the ABCB1 C3435T T allele and nonresponse to methotrexate (MTX) treatment (OR 1.201, 95 % CI 0.456-3.164, p = 0.711). However, the analysis did indicate that MTX toxicity was associated with the ABCB1 C3435T polymorphism in RA under an overdominant model (TC vs. TT + CC; OR 0.483, 95 % CI 0.259-0.900, p = 0.022), evidencing a lower risk of MTX toxicity for heterozygotes (TC) than homozygotes (TT and CC). This meta-analysis demonstrated that the ABCB1 C3435T polymorphism may be not associated with responsiveness to DMARD therapy, but may be associated with MTX toxicity in RA.

The C677T polymorphism in the MTHFR gene is associated with the toxicity of methotrexate in a Spanish rheumatoid arthritis population

Objective: Methotrexate (MTX) is the first-choice drug for the treatment of rheumatoid arthritis (RA) patients. However, 30% of RA patients discontinue therapy within 1 year, usually because of adverse effects. Previous studies have reported conflicting results on the association of polymorphisms in the MTHFR gene with the toxicity of MTX in RA. The aim of this study was to assess the involvement of the C677T and A1298C polymorphisms in the MTHFR gene in the toxicity of MTX in a Spanish RA population.Methods: The study included retrospectively 468 Spanish RA patients treated with MTX. Single nucleotide polymorphism (SNP) genotyping was performed using the oligonucleotide microarray technique. Allele and genotype association analyses with regard to MTX toxicity and a haplotype association test were also performed.Results: Eighty-four out of the 468 patients (18%) had to discontinue therapy due to adverse effects or MTX toxicity. The C677T polymorphism (rs1801133) was associated with increased MTX toxicity [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.01–1.98, p = 0.0428], and the strongest association was shown in the recessive model (OR 1.95, 95% CI 1.08–3.53, p = 0.0246). The A1298C polymorphism (rs1801131) was not associated with increased MTX toxicity (OR 0.94, 95% CI 0.65–1.38, p = 0.761). A borderline significant risk haplotype was found: 677T-1298A (OR 1.40, 95% CI 1.00–1.96, p = 0.0518).Conclusion: These results demonstrate that the C677T polymorphism in the MTHFR gene is associated with MTX toxicity in a Spanish RA population.

Associations between the C677T and A1298C Polymorphisms of MTHFR and the Efficacy and Toxicity of Methotrexate in Rheumatoid Arthritis

The C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene have been reported to be associated with the toxicity and efficacy of methotrexate in rheumatoid arthritis (RA), although the results of previous studies have been inconsistent. The aim of this study was to explore whether the C677T and A1298C polymorphisms of MTHFR play a role in the toxicity and efficacy of methotrexate in RA. The authors identified and evaluated studies conducted on the association between the C677T and A1298C polymorphisms of MTHFR and on the toxicity and efficacy of methotrexate in RA. A meta-analysis was then conducted to compare the toxicity and efficacy of methotrexate with respect to the 677CC and 677CT/TT genotypes and the 1298AA and 1298AC/CC genotypes. Eight studies, which included a total of 1514 patients with RA, were included in this meta-analysis. Meta-analysis did not show any association between the C677T and A1298C polymorphisms of MTHFR and the toxicity of methotrexate in RA in all patients or in Asian patients. The odds ratios (ORs) for adverse effects with 677CC versus 677CT/TT in all patients and in Asian patients were 0.633 (95% CI 0.325, 1.234; p = 0.180) and 0.621 (95% CI 0.233, 1.655; p = 0.341), respectively. The ORs for adverse effects with 1298AA versus 1298AC/CC in all patients and in Asian patients were 0.942 (95% CI 0.479, 1.851; p = 0.861) and 0.978 (95% CI 0.569, 1.681; p = 0.936), respectively. Heterogeneities were evident among the included studies. In addition, no association was found between the C677T and A1298C polymorphisms and the efficacy of methotrexate in RA in all patients. Our meta-analysis including 1514 patients with RA found no association between the C677T and A1298C polymorphisms of MTHFR and the toxicity and efficacy of methotrexate in RA. Because of the paucity of pharmacogenetic data, further studies are needed to determine the role of MTHFR polymorphisms in the toxicity and efficacy of methotrexate.