Editorial: Monitoring methotrexate polyglutamates in Crohn's disease-Authors' reply

This article is linked to van de Meeberg et al papers. To view these articles, visit https://doi.org/10.1111/apt.17719 and https://doi.org/10.1111/apt.17743

Therapeutic drug monitoring of methotrexate in patients with Crohn's disease

BACKGROUND

Therapeutic drug monitoring (TDM) has the potential to improve efficacy and diminish side effects. Measuring methotrexate-polyglutamate (MTX-PG) in erythrocytes might enable TDM for methotrexate in patients with Crohn's disease (CD).

AIM

To investigate the relationship between MTX-PGs and methotrexate drug survival, efficacy and toxicity METHODS: In a multicentre prospective cohort study, patients with CD starting subcutaneous methotrexate without biologics were included and followed for 12 months. Primary outcome was subcutaneous methotrexate discontinuation or requirement for step-up therapy. Secondary outcomes included faecal calprotectin (FCP), Harvey Bradshaw Index (HBI), hepatotoxicity and gastrointestinal intolerance. Erythrocyte MTX-PGs were analysed at weeks 8, 12, 24 and 52 or upon treatment discontinuation.

RESULTS

We included 80 patients with CD (mean age 55 ± 13y, 35% male) with a median FCP of 268 μg/g (IQR 73-480). After the 12-month visit, 21 patients (26%) were still on subcutaneous methotrexate monotherapy. Twenty-one patients stopped because of disease activity, 29 because of toxicity, and four for both reasons. Five patients ended study participation or stopped methotrexate for another reason. A higher MTX-PG3 concentration was associated with a higher rate of methotrexate drug survival (HR 0.86, 95% CI 0.75-0.99), lower FCP (β -3.7, SE 1.3, p < 0.01) and with biochemical response (FCP ≤250 if baseline >250 μg/g; OR 1.1, 95% CI 1.0-1.3). Higher MTX-PGs were associated with less gastrointestinal intolerance. There was no robust association between MTX-PGs and HBI or hepatotoxicity.

CONCLUSIONS

Higher MTX-PG3 concentrations are related to better methotrexate drug survival and decreased FCP levels. Therefore, MTX-PG3 could be used for TDM if a target concentration can be established.

Oral Versus Subcutaneous Methotrexate in Immune-Mediated Inflammatory Disorders: an Update of the Current Literature

PURPOSE

This review aims to critically evaluate the potential benefit of either oral or subcutaneous administration of methotrexate (MTX) in various immune-mediated inflammatory disorders (IMIDs) through analysis of efficacy, toxicity, pharmacokinetics and pharmacodynamics of both administration routes.

RECENT FINDINGS

Recent studies comparing the efficacy of oral versus subcutaneous MTX administration in IMIDs have revealed contradicting results. Some reported higher efficacy with subcutaneous administration, while others found no significant difference. Regarding toxicity, some studies have challenged the notion that subcutaneous administration is better tolerated than oral administration, while others have supported this. Pharmacokinetic studies suggest higher plasma bioavailability and increased accumulation of MTX-polyglutamates (MTX-PGs) in red blood cells (RBCs) with subcutaneous administration during the initial treatment phase. However, after several months, similar intracellular drug levels are observed with both administration routes. There is no conclusive evidence supporting the superiority of either oral or subcutaneous MTX administration in terms of efficacy and adverse events in IMIDs. Subcutaneous administration leads to higher plasma bioavailability and initial accumulation of MTX-PGs in RBCs, but the difference seems to disappear over time. Given the variable findings, the choice of administration route may be based on shared decision-making, offering patients the option of either oral or subcutaneous administration of MTX based on individual preferences and tolerability. Further research is needed to better understand the impact of MTX-PGs in various blood cells and TDM on treatment response and adherence to MTX therapy.

A meta-analysis of methotrexate polyglutamates in relation to efficacy and toxicity of methotrexate in inflammatory arthritis, colitis and dermatitis

AIMS

In immune-mediated inflammatory diseases (IMIDs), early symptom control is a key therapeutic goal. Methotrexate (MTX) is the first-line treatment across IMIDs. However, MTX is underutilized and suboptimally dosed, partly due to the inability of making individualized treatment decisions through therapeutic drug monitoring (TDM). To implement TDM in clinical practice, establishing a relationship between drug concentration and disease activity is paramount. In this meta-analysis, we investigated the relationship between concentrations of MTX polyglutamates (MTX-PG) in erythrocytes and efficacy as well as toxicity across IMIDs.

METHODS

Studies analysing MTX-PG in relation to disease activity and/or toxicity were included for inflammatory arthritis (rheumatoid [RA] and juvenile idiopathic arthritis [JIA]), inflammatory bowel disease (Crohn's and ulcerative colitis) and dermatitis (psoriasis and atopic dermatitis). Meta-analyses were performed resulting in several summary effect measures: regression coefficient (β), correlation coefficient and mean difference (of MTX-PG in responders vs. nonresponders) for IMIDs separately and collectively.

RESULTS

Twenty-five studies were included. In RA and JIA, higher MTX-PG was significantly associated with lower disease activity at 3 months (β: -0.002; 95% confidence interval [CI]: -0.004 to -0.001) and after 4 months of MTX use (β: -0.003; 95% CI: -0.005 to -0.002). Similarly, higher MTX-PG correlated with lower disease activity in psoriasis (R: -0.82; 95% CI: -0.976 to -0.102). Higher MTX-PG was observed in RA, JIA and psoriasis responders (mean difference: 5.2 nmol/L MTX-PG_total ; P < .01).

CONCLUSION

We showed that higher concentrations of erythrocyte MTX-PG were associated with lower disease activity in RA, JIA and psoriasis. These findings are an important step towards implementation of TDM for MTX treatment across IMIDs.

Development and validation of a prognostic multivariable model to predict insufficient clinical response to methotrexate in rheumatoid arthritis

Objective

The objective was to predict insufficient response to 3 months methotrexate (MTX) in DMARD naïve rheumatoid arthritis patients.

Methods

A Multivariable logistic regression model of rheumatoid arthritis patients starting MTX was developed in a derivation cohort with 285 patients starting MTX in a clinical multicentre, stratified single-blinded trial, performed in seven secondary care clinics and a tertiary care clinic. The model was validated in a validation cohort with 102 patients starting MTX at a tertiary care clinic. Outcome was insufficient response (disease activity score (DAS)28 >3.2) after 3 months of MTX treatment. Clinical characteristics, lifestyle variables, genetic and metabolic biomarkers were determined at baseline in both cohorts. These variables were dichotomized and used to construct a multivariable prediction model with backward logistic regression analysis.

Results

The prediction model for insufficient response in the derivation cohort, included: DAS28>5.1, Health Assessment Questionnaire>0.6, current smoking, BMI>25 kg/m², ABCB1 rs1045642 genotype, ABCC3 rs4793665 genotype, and erythrocyte-folate<750 nmol/L. In the derivation cohort, AUC of ROC curve was 0.80 (95%CI: 0.73–0.86), and 0.80 (95%CI: 0.69–0.91) in the validation cohort. Betas of the prediction model were transformed into total risk score (range 0–8). At cutoff of ≥4, probability for insufficient response was 44%. Sensitivity was 71%, specificity 72%, with positive and negative predictive value of 72% and 71%.

Conclusions

A prognostics prediction model for insufficient response to MTX in 2 prospective RA cohorts by combining genetic, metabolic, clinical and lifestyle variables was developed and validated. This model satisfactorily identified RA patients with high risk of insufficient response to MTX.

Methotrexate intolerance in oral and subcutaneous administration in patients with juvenile idiopathic arthritis: a cross-sectional, observational study

OBJECTIVES

Methotrexate (MTX) is the cornerstone disease-modifying anti-rheumatic drug (DMARD) in juvenile idiopathic arthritis (JIA). In Dutch patients, MTX intolerance occurred frequently and was associated with subcutaneous (SC) administration. The aim of this study was to assess the prevalence of MTX intolerance and its association with the route of administration in a German cohort of JIA patients.

METHODS

A cross-sectional study of JIA patients on MTX was performed. Primary outcome was MTX intolerance, which was determined using the validated Methotrexate Intolerance Severity Score (MISS) questionnaire. The prevalence of gastrointestinal adverse effects and MTX intolerance was compared between patients on MTX SC and MTX administered orally (PO).

RESULTS

Of 179 JIA patients on MTX, 73 (40.8%) were intolerant. The odds of MTX intolerance were higher in patients using MTX exclusively SC compared to exclusively PO (adjusted odds ratio 3.37 [95% confidence interval 1.19-10.0]). There was strong evidence that the former experienced more behavioural complaints (76.1% vs. 47.4%, p=0.001) and weak evidence that they experienced more abdominal pain after MTX intake (43.5% vs. 27.4%, p=0.056).

CONCLUSIONS

The prevalence of MTX intolerance was high and exclusively SC administration of MTX was associated with MTX intolerance and behavioural adverse effects. The prevalence of gastrointestinal adverse effects was at least as high as in patients on MTX PO. The frequently held assumption that SC causes fewer side effects than PO seems unwarranted. Definite answers about the differences between SC and PO administration with respect to safety and efficacy should be obtained by randomised trials.

Methotrexate treatment affects effector but not regulatory T cells in juvenile idiopathic arthritis

OBJECTIVE

The balance between Treg and effector T cells (Teff) is crucial for immune regulation in JIA. How MTX, the cornerstone treatment in JIA, influences this balance in vivo is poorly elucidated. The aim of this study was to investigate quantitative and qualitative effects of MTX on Treg and Teff in JIA patients during MTX treatment.

METHODS

Peripheral blood samples were obtained from JIA patients at the start of MTX and 3 and 6 months thereafter. Treg numbers and phenotypes were determined by flow cytometry and suppressive function in allogeneic suppression assays. Teff proliferation upon stimulation with anti-CD3, activation status and intracellular cytokine production were determined by flow cytometry. Effector cell responsiveness to suppression was investigated in autologous suppression assays. Effector cell cytokines in supernatants of proliferation and suppression assays and in plasma were measured by cytokine multiplex assay.

RESULTS

MTX treatment in JIA did not affect Treg phenotype and function. Instead, MTX treatment enhanced, rather than diminished, CD4(+) and CD8(+) T cell proliferation of JIA patients after 6 months of therapy, independent of clinical response. Effector cells during MTX treatment were equally responsive to Treg-mediated suppression. MTX treatment did not attenuate Teff activation status and their capacity to produce IL-13, IL-17, TNF-α and IFN-γ. Similarly to Teff proliferation, plasma IFN-γ concentrations after 6 months were increased.

CONCLUSION

This study provides the novel insight that MTX treatment in JIA does not attenuate Teff function but, conversely, enhances T cell proliferation and IFN-γ plasma concentrations in JIA patients.

Prediction of methotrexate intolerance in juvenile idiopathic arthritis: a prospective, observational cohort study

BACKGROUND

Methotrexate (MTX) is an effective and safe drug in the treatment of juvenile idiopathic arthritis (JIA). Despite its safety, MTX-related gastrointestinal adverse effects before and after MTX administration, termed MTX intolerance, occur frequently, leading to non-compliance and potentially premature MTX termination. The aim of this study was to construct a risk model to predict MTX intolerance.

METHODS

In a prospective JIA cohort, clinical variables and single nucleotide polymorphisms were determined at MTX start. The Methotrexate Intolerance Severity Score was employed to measure MTX intolerance in the first year of treatment. MTX intolerance was most prevalent at 6 or 12 months after MTX start, which was defined as the outcome for the prediction model. The model was developed in 152 patients using multivariable logistic regression analysis and subsequently internally validated using bootstrapping.

RESULTS

The prediction model included the following predictors: JIA category, antinuclear antibody, parent/patient assessment of pain, Juvenile Arthritis Disease Activity Score-27, thrombocytes, alanine aminotransferase and creatinine. The model classified 77.5% of patients correctly, and 66.7% of patients after internal validation by bootstrapping. The lowest predicted risk of MTX intolerance was 18.9% and the highest predicted risk was 85.9%. The prediction model was transformed into a risk score (range 0-17). At a cut-off of ≥6, sensitivity was 82.0%, specificity 56.1%, positive predictive value was 58.7% and negative predictive value 80.4%.

CONCLUSIONS

This clinical prediction model showed moderate predictive power to detect MTX intolerance. To develop into a clinically usable tool, it should be validated in an independent cohort and updated with new predictors. Such an easy-to-use tool could then assist clinicians in identifying patients at risk to develop MTX intolerance, and in turn to monitor them closely and intervene timely in order to prevent the development of MTX intolerance.

TRIAL REGISTRATION

ISRCTN register, www.isrctn.com, ISRCTN13524271.

Methotrexate polyglutamates in erythrocytes are associated with lower disease activity in juvenile idiopathic arthritis patients

OBJECTIVE

To determine association of erythrocyte methotrexate polyglutamates (MTX-PG) with disease activity and adverse effects in a prospective juvenile idiopathic arthritis (JIA) cohort.

METHODS

One hundred and thirteen JIA patients were followed from MTX start until 12 months. Erythrocyte MTX-PGs with 1-5 glutamate residues were measured at 3 months with tandem mass spectrometry. The outcomes were Juvenile Arthritis Disease Activity Score (JADAS)-27 and adverse effects. To determine associations of MTX-PGs with JADAS-27 at 3 months and during 1 year of MTX treatment, linear regression and linear mixed-model analyses were used. To determine associations of MTX-PGs with adverse effects during 1 year of MTX treatment, logistic regression was used. Analyses were corrected for JADAS-27 at baseline and co-medication.

RESULTS

Median JADAS-27 decreased from 12.7 (IQR: 7.8-18.2) at baseline to 2.9 (IQR: 0.1-6.5) at 12 months. Higher concentrations of MTX-PG3 (β: -0.006, p=0.005), MTX-PG4 (β: -0.015, p=0.004), MTX-PG5 (β: -0.051, p=0.011) and MTX-PG3-5 (β: -0.004, p=0.003) were associated with lower disease activity at 3 months. Higher concentrations of MTX-PG3 (β: -0.005, p=0.028), MTX-PG4 (β: -0.014, p=0.014), MTX-PG5 (β: -0.049, p=0.023) and MTX-PG3-5 (β: -0.004, p=0.018) were associated with lower disease activity over 1 year. None of the MTX-PGs was associated with adverse effects.

CONCLUSIONS

In the first prospective study in JIA, long-chain MTX-PGs were associated with lower JADAS-27 at 3 months and during 1 year of MTX treatment. Erythrocyte MTX-PG could be a plausible candidate for therapeutic drug monitoring of MTX in JIA.

Prevalence of methotrexate intolerance in rheumatoid arthritis and psoriatic arthritis

INTRODUCTION

The aim of this study was to determine the prevalence of gastrointestinal and behavioural symptoms occurring before (anticipatory/associative) and after methotrexate (MTX) administration, termed MTX intolerance, in rheumatoid (RA) and psoriatic arthritis (PsA).

METHODS

Methotrexate Intolerance Severity Score (MISS), previously validated in juvenile idiopathic arthritis patients, was used to determine MTX intolerance prevalence in 291 RA/PsA patients. The MISS consisted of four domains: abdominal pain, nausea, vomiting and behavioural symptoms, occurring upon, prior to (anticipatory) and when thinking of MTX (associative). MTX intolerance was defined as ≥6 on the MISS with ≥1 point on anticipatory and/or associative and/or behavioural items.

RESULTS

A total of 123 patients (42.3%) experienced at least one gastrointestinal adverse effect. The prevalence of MTX intolerance was 11%. MTX intolerance prevalence was higher in patients on parenteral (20.6%) than on oral MTX (6.2%) (p < 0.001).

CONCLUSION

Besides well-known gastrointestinal symptoms after MTX, RA and PsA patients experienced these symptoms also before MTX intake. RA and PsA patients on MTX should be closely monitored with the MISS for early detection of MTX intolerance, in order to intervene timely and avoid discontinuation of an effective treatment.