Genetic variation in the SLC19A1 gene and methotrexate toxicity in rheumatoid arthritis patients.

AIM: We investigated the clinical relevance of SLC19A1 genetic variability for methotrexate (MTX) toxicity in rheumatoid arthritis patients using a haplotype-based approach. PATIENTS & METHODS: Two hundred and twelve unrelated rheumatoid arthritis patients and 89 lymphoblastoid cell lines were used to investigate the effect of SLC19A1 SNPs and haplotypes on MTX adverse events and treatment discontinuation. RESULTS: Two putatively functional SNPs in high linkage disequilibrium, rs1051266 and rs1131596, were associated with protection (hazard ratio: 0.33; 95% CI: 0.16-0.69; adjusted p = 0.021 and hazard ratio: 0.38; 95% CI: 0.17-0.27; adjusted p = 0.021, respectively) of discontinuation of MTX treatment owing to toxicity. These SNPs were also associated with protection from infections. SLC19A1 haplotype analysis found significant associations with MTX discontinuation owing to toxicity (p = 0.025). Quantification of SLC19A1 mRNA in cell lines suggested that rs1131596 was not a major causal variant. CONCLUSION: Individual SNP and haplotype analyses suggest that rs1051266 could be a functional variant altering MTX toxicity; however, validation in independent studies is needed.

Investigation of the influence of CYP1A2 and CYP2C19 genetic polymorphism on 2-Cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide (A77 1726) pharmacokinetics in leflunomide-treated patients with rheumatoid arthritis.

Leflunomide is a disease-modifying antirheumatic drug used for the treatment of rheumatoid arthritis (RA). Cytochromes P450, mainly CYP1A2 and CYP2C19, may be involved in the transformation of leflunomide to leflunomide metabolite (A77 1726, 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide). The aim of this study was to investigate whether genetic polymorphisms in CYP1A2 and CYP2C19 influence leflunomide pharmacokinetics, treatment response, and the occurrence of adverse drug reactions (ADRs). The study included 67 patients with RA and 4 patients with polyarthritis resembling RA and psoriasis treated with leflunomide. A77 1726 steady-state plasma concentrations were determined by validated high-performance liquid chromatography with UV detection. A population pharmacokinetic model was developed to estimate the oral clearance (CL/F) and volume of distribution (V/F). A genotyping approach was used to determine C-163A, C-729T, and T-739G in the CYP1A2 gene as well as single nucleotide polymorphisms that characterize CYP2C19*2, *3, *4, and *17 alleles. A large interindividual variability in trough A77 1726 steady-state plasma concentrations was observed (from 1.9 to 156.9 mg/l). A77 1726 CL/F was 71% higher in carriers of the CYP2C19*2 allele compared with noncarriers. The A77 1726 average steady-state plasma concentration was associated with the treatment response. Patients with a greater decrease in C-reactive protein (CRP) had higher average steady-state plasma A77 1726 concentrations: 49.7 +/- 39.0 mg/l in patients with DeltaCRP of more than 8.5 mg/l compared with 24.8 +/- 13.7 mg/l in patients with DeltaCRP of

Genetic determinants of methotrexate toxicity in rheumatoid arthritis patients: a study of polymorphisms affecting methotrexate transport and folate metabolism.

OBJECTIVE: Methotrexate (MTX) is a disease-modifying antirheumatic drug used in the treatment of rheumatoid arthritis (RA). Genetic polymorphisms of reduced folate carrier (RFC1 A80G), P-glycoprotein (MDR1 G2677T>A/C and C3435T), 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), thymidylate synthase (TS 2R-->3R), methionine synthase (MS A2756G) and methionine synthase reductase (MTRR A66G) modify MTX transport and metabolic effects and may influence the treatment response. METHODS: A genotyping approach was used to determine the studied polymorphisms in 213 RA patients. RESULTS: We observed that 56 (26.3%) patients discontinued MTX treatment due to poor response and/or toxicity. RFC1 A80G and MDR1 C3435T polymorphisms increased the risk for overall MTX toxicity (P = 0.039, OR = 3.574, 95% CI = 1.065-11.993 and P = 0.032, OR = 7.801, 95% CI = 1.194-50.960 respectively), while MTHFR A1298C polymorphism had a protective effect on overall MTX toxicity (P = 0.027, OR = 0.170, 95% CI = 0.035-0.820). CONCLUSION: Our results suggest that genetic polymorphisms in the folate metabolic pathway and MTX transporters modify the toxicity but not the efficacy of MTX treatment.

Genetic polymorphism of CYP1A2 and the toxicity of leflunomide treatment in rheumatoid arthritis patients.

OBJECTIVE: Leflunomide is a disease-modifying antirheumatic drug used for treating rheumatoid arthritis (RA). In vitro studies demonstrated that cytochromes P450 (CYPs), mainly CYP1A2 and CYP2C19, might be involved in leflunomide activation. The aim of our study was to investigate whether genetic polymorphisms of CYP1A2, CYP2C19, and CYP2C9 influence leflunomide toxicity. METHODS: A genotyping approach was used to determine CYP1A2*1F, CYP2C19*2, CYP2C19*17, CYP2C9*2, and CYP2C9*3 alleles in 105 RA patients. RESULTS: Leflunomide treatment was well tolerated by 62 patients, whereas 43 patients discontinued the treatment within the first year due to toxicity. Patients with CYP1A2*1F CC genotype had a 9.7-fold higher risk for overall leflunomide-induced toxicity than did the carriers of CYP1A2*1F A allele [P = 0.002, odds ratio = 9.708, 95% confidence interval = 2.276-41.403]. No significant association between the CYP2C19 and CYP2C9 genotypes and the leflunomide toxicity was observed. CONCLUSION: Our results suggest that the CYP1A2*1F allele may be associated with leflunomide toxicity in RA patients.

Subcutaneous infection with Pseudallescheria boydii in an immunocompromised patient.

With the broad employment of immunosuppressive therapy, the incidence of Pseudallescheria boydii infections is rising. We report a first case of the localized subcutaneous P. boydii infection in a patient with microscopic polyangiitis. Favorable outcome related to the treatment with voriconazole adds to the growing body of evidence supporting the use of this particular agent in P. boydii infections.