Maja Bulatović

High prevalence of methotrexate intolerance in juvenile idiopathic arthritis: development and validation of a methotrexate intolerance severity score

OBJECTIVE To design and validate a new questionnaire for identifying patients with methotrexate (MTX) intolerance, and to determine the prevalence of MTX intolerance in patients with juvenile idiopathic arthritis (JIA) using this questionnaire. METHODS The MTX Intolerance Severity Score (MISS) questionnaire was constructed, consisting of 5 domains: stomach ache, nausea, vomiting, sore mouth, and behavioral symptoms. The domains each consisted of 3 questions pertaining to the presence of a symptom upon, prior to (anticipatory), and when thinking of (associative) MTX intake. The MISS questionnaire was validated in 86 patients by determining its discriminative power between patients with and those without MTX intolerance, identified as such by a gold standard (physicians opinion). Using the MISS questionnaire, the prevalence of MTX intolerance was determined in 297 JIA patients. RESULTS The MISS questionnaire discriminated well between MTX-intolerant and MTX-tolerant patients. A cutoff score of 6 yielded the best sensitivity (88%) and specificity (80%). MTX intolerance was found in 150 (50.5%) of 297 patients. Of 220 patients receiving oral MTX, 98 (44.5%) experienced MTX intolerance, whereas 67.5% of 77 patients receiving parenteral MTX experienced intolerance to the drug (P = 0.001). CONCLUSION Our findings indicate that the MISS questionnaire is a highly sensitive and specific tool for the diagnosis of MTX intolerance, and that there is a high prevalence of MTX intolerance among JIA patients. The prevalence of intolerance in patients receiving parenteral MTX exceeds that in patients receiving oral MTX. The frequent occurrence of anticipatory and associative symptoms suggests that classic conditioning plays an important role in MTX intolerance.

ABCB1 and ABCC3 Gene Polymorphisms Are Associated with First-year Response to Methotrexate in Juvenile Idiopathic Arthritis

Objective. Although methotrexate (MTX) is the most widely prescribed drug in juvenile idiopathic arthritis (JIA), 30% of patients fail to respond to it. To individualize treatment strategies, the genetic determinants of response to MTX should be identified. Methods. A cohort of 287 patients with JIA treated with MTX was studied longitudinally over the first year of treatment. MTX response was defined as the American College of Rheumatology pediatric 70 criteria (ACRped70). We genotyped 21 single-nucleotide polymorphisms in 13 genes related to MTX polyglutamylation and to cellular MTX uptake and efflux. Potential associations between ACRped70 and genotypes were analyzed in a multivariate model and corrected for these 3 covariates: disease duration prior to MTX treatment, physician’s global assessment of disease activity at baseline, and MTX dose at all study visits. Results. MTX response was more often achieved by patients variant for the adenosine triphosphate-binding cassette transporter B1 (ABCB1) gene polymorphism rs1045642 (OR 3.80, 95% CI 1.70−8.47, p = 0.001) and patients variant for the ABCC3 gene polymorphism rs4793665 (OR 3.10, 95% CI 1.49−6.41, p = 0.002) than by patients with other genotypes. Patients variant for the solute carrier 19A1 (SLC19A1) gene polymorphism rs1051266 were less likely to respond to MTX (OR 0.25, 95% CI 0.09−0.72, p = 0.011). Conclusion. ABCB1 rs1045642, ABCC3 rs4793665, and SLC19A1 rs1051266 polymorphisms were associated with response to MTX in 287 patients with JIA studied longitudinally. Upon validation of our results in other JIA cohorts, these genetic determinants may help to individualize treatment strategies by predicting clinical response to MTX.

Methotrexate polyglutamates in erythrocytes are associated with lower disease activity in patients with rheumatoid arthritis.

Objective To investigate if erythrocyte-methotrexate-polyglutamate (MTX-PG) concentrations in patients with rheumatoid arthritis (RA) are associated with disease activity or adverse events. Methods We used a longitudinal study design with two cohorts. The derivation cohort included 102 and the validation cohort included 285 patients with RA on MTX. We measured erythrocyte-MTX-PG with 1–5 glutamate residues at 3 months, 6 months and 9 months after MTX start with a liquid chromatography (LC)-mass spectrometry (MS)/MS assay. Outcomes were disease activity score in 28 joints (DAS28) and adverse events. Longitudinal associations of MTX-PG concentrations after 3 months, 6 months and 9 months with DAS28 were tested with a linear mixed model adjusted for age, gender, baseline DAS28, MTX dose and comedication. Results In the derivation cohort, mean DAS28 decreased from 4.26 (SE=0.14) at baseline to 2.72 (SE=0.13) after 9 months. Thirty per cent of patients in the derivation cohort experienced more than three adverse events after 3 months, which decreased to 18% after 9 months. In the validation cohort, DAS28 and adverse events were comparable with the derivation cohort. In the derivation cohort, MTX-PG1 (ß=−0.005), MTX-PG2 (ß=−0.022), MTX-PG3 (β=−0.007) and total MTX-PG (ß=−0.004) were associated (p<0.05) with lower DAS28 over 9 months. In the validation cohort, MTX-PG2 (ß=−0.015), MTX-PG3 (ß=−0.010), MTX-PG4 (ß=−0.008) and total MTX-PG (ß=−0.003) were associated with lower DAS28 over 9 months. None of the MTX-PGs was associated with adverse events. Conclusions In this first longitudinal study, we showed that an increase in erythrocyte-MTX-PG concentration was associated with a decreased DAS28 over 9 months in two cohorts, and is therefore a potential tool for therapeutic drug monitoring of MTX in RA.

Treatment of methotrexate (MTX) intolerance: behavioural therapy, versus switch to parenteral MTX versus oral MTX

Methods 45 JIA patients with MTX intolerance were randomised to receive oral MTX with anti-emetics (standard of care), parenteral MTX or oral MTX with behavioural therapy. Primary outcome was the occurrence of MTX intolerance, defined as ≥5 points on a validated MISS questionnaire, after a 3-month intervention period. Secondary outcome measures were: MTX intolerance after 6 and 12 months and the number of patients that discontinued MTX or switched to another treatment arm due to intolerance.

Methotrexate restores effector T cell responsiveness in juvenile idiopathic arthritis

Methods Peripheral blood mononuclear cells (PBMCs) of 25 JIA patients were isolated prior to the start of MTX (T0) and 3 (T3) and 6 (T6) months after MTX start. Frequency and phenotype of FoxP3+ Tregs were analyzed ex vivo by flow cytometry and their suppressive function in CFSE suppression assays. Proliferation of CD4+ and CD8+ Teffs was determined with CFSE upon a 4-day culture in the presence of anti-CD3. Teffs cytokine production was measured ex vivo by flow cytometry upon PMA/ionomycin stimulation and in culture supernatants with luminex.

Validation of the juvenile artritis disease activity score in 1124 patient visits

Methods 1124 visits in 255 JIA patients were evaluated. Correlations of JADAS-27 (range 0-57) with JADAS-10, JADAS-71, core-set criteria, Disease Activity Index (DAS-28), and Clinical Disease Activity Index (CDAI) were analyzed in the total group and treatment groups. Responsiveness to minimal clinically important difference (MCID) was analyzed longitudinally. Worsening was defined as a flare with at least 20% PGA and 15% ESR increase, as well as starting therapy, or drug dosage escalation. Improvement was defined as reaching ACRped50 or as reduction of medication.