Methotrexate in rheumatoid arthritis. A five-year prospective multicenter study

Detecting and exploiting the circadian clock in rheumatoid arthritis

Over the past four decades, research on 24-h rhythms has yielded numerous remarkable findings, revealing their genetic, molecular, and physiological significance for immunity and various diseases. Thus, circadian rhythms are of fundamental importance to mammals, as their disruption and misalignment have been associated with many diseases and the abnormal functioning of many physiological processes. In this article, we provide a brief overview of the molecular regulation of 24-h rhythms, their importance for immunity, the deleterious effects of misalignment, the link between such pathological rhythms and rheumatoid arthritis (RA), and the potential exploitation of chronobiological rhythms for the chronotherapy of inflammatory autoimmune diseases, using RA as an example.

What do patients on methotrexate need and expect at the clinic? An online patient survey

To verify, via a survey, the experience and needs of patients receiving methotrexate (MTX), their general management and the quality of the information provided by the rheumatologist. We conducted a 51-item online survey between May and July 2020 addressed to persons diagnosed with an immune-mediated disease and treated with MTX (regardless of the route of administration). Recruitment was done via Twitter. We obtained 294 responses, of which 283 were complete and could be analysed. Almost 82% of the respondents were women, 80% resided in Spain, 75% were between 31 and 60 years old, and 57% were active workers. Diseases included psoriasis (41%), lupus, Sjögren's or vasculitides (33%), and rheumatoid arthritis (16%), among others. Eighty per cent had read the leaflet inserted in the package, of whom 62% found it helpful. Only 15% of the respondents reported having been offered additional written material, which was considered barely functional (33 out of 100). Most patients (88%) responded that they had not received advice on any reliable sources to consult on the internet, and those who received it considered it unhelpful (24 out of 100). Patients receiving MTX due to an autoimmune disease demand more and better-quality written or web-based information than what is currently offered at their clinics.

MTHFR c.665C>T and c.1298A>C Polymorphisms in Tailoring Personalized Anti-TNF-α Therapy for Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease with a prevalence of 1%. Currently, RA treatment aims to achieve low disease activity or remission. Failure to achieve this goal causes disease progression with a poor prognosis. When treatment with first-line drugs fails, treatment with tumor necrosis factor-α (TNF-α) inhibitors may be prescribed to which many patients do not respond adequately, making the identification of response markers urgent. This study investigated the association of two RA-related genetic polymorphisms, c.665C>T (historically referred to as C677T) and c.1298A>C, in the MTHFR gene as response markers to an anti-TNF-α therapy. A total of 81 patients were enrolled, 60% of whom responded to the therapy. Analyses showed that both polymorphisms were associated with a response to therapy in an allele dose-dependent manner. The association for c.665C>T was significant for a rare genotype (p = 0.01). However, the observed opposite trend of association for c.1298A>C was not significant. An analysis revealed that c.1298A>C, unlike c.665C>T, was also significantly associated with the drug type (p = 0.032). Our preliminary results showed that the genetic polymorphisms in the MTHFR gene were associated with a response to anti-TNF-α therapy, with a potential significance for the anti-TNF-α drug type. This evidence suggests a role for one-carbon metabolism in anti-TNF-α drug efficacy and contributes to further personalized RA interventions.

Bacteroides fragilis participates in the therapeutic effect of methotrexate on arthritis through metabolite regulation

Methotrexate (MTX) is a preferred disease-modifying anti-rheumatic drug in the management of rheumatoid arthritis (RA). However, the toxicity and inefficiency of MTX limit its clinical application. Gut microbiota has been implicated in the side effects and efficacy of MTX. In this study, the analysis of the gut microbiota in RA patients revealed that the abundances of intestinal Bacteroides fragilis was reduced after MTX treatment. We observed that MTX has no obvious therapeutic effect in the absence of B. fragilis, while transplantation of B. fragilis restored the efficacy of MTX in antibiotics-pretreated collagen-induced arthritis (CIA) mice. In addition, B. fragilis gavage was accompanied by an increase in butyrate. Supplementation of butyrate restored the response to MTX in gut microbiota-deficient mice, to a similar level achieved by B. fragilis gavage. These results show that gut microbiota-regulated butyrate plays an essential role in the efficacy of MTX, which will provide new strategies to improve the effectiveness of methotrexate in RA treatment.

Prevalence and predictors of adverse events with methotrexate mono- and combination-therapy for rheumatoid arthritis: a systematic review

OBJECTIVES

This systematic review aims to summarize rates of adverse events (AEs) in patients with RA or inflammatory arthritis starting MTX as monotherapy or in combination with other csDMARDs, and to identify reported predictors of AEs.

METHODS

Three databases were searched for studies reporting AEs in MTX-naïve patients with RA. Randomized controlled trials (RCTs) and observational cohort studies were included. Prevalence rates of AEs were pooled using random effects meta-analysis, stratified by study design.

RESULTS

Forty-six articles (34 RCTs and 12 observational studies) were identified. The pooled prevalence of total AEs was 80.1% in RCTs (95% CI: 73.5, 85.9), compared with 23.1% in observational studies (95% CI: 12.3, 36.0). The pooled prevalence of serious AEs was 9.5% in RCTs (95% CI: 7.4, 11.7), and 2.1% in observational studies (95% CI: 1.0, 3.4). MTX discontinuation due to AEs was higher in observational studies (15.5%, 95% CI: 9.6, 22.3) compared with RCTs (6.7%, 95% CI: 4.7, 8.9). Gastrointestinal events were the most commonly reported AEs (pooled prevalence: 32.7%, 95% CI: 18.5, 48.7). Five studies examined predictors of AEs. RF status, BMI and HAQ score were associated with MTX discontinuation due to AEs; ACPA negativity, smoking and elevated creatinine were associated with increased risk of elevated liver enzymes.

CONCLUSION

The review provides an up-to-date overview of the prevalence of AEs associated with MTX in patients with RA. The findings should be communicated to patients to help them make informed choices prior to commencing MTX.

Assessing methotrexate intolerance and its prevalence in rheumatoid arthritis: Development and validation of the MISA questionnaire

OBJECTIVE

Methotrexate (MTX) intolerance refers to unpleasant symptoms that accompany use of MTX. Although a validated questionnaire on MTX intolerance exists for children with juvenile idiopathic arthritis, it is lacking for adult rheumatoid arthritis (RA) patients.

METHODS

A 10-item questionnaire called Methotrexate Intolerance and Severity assessment in Adults (MISA) was developed to assess MTX intolerance. On receiver operating characteristic analysis, its predictive ability was compared to Methotrexate Intolerance Severity Score (MISS), a validated questionnaire for children. Subsequently, prevalence and associations of intolerance were assessed in 414 RA patients. After 1 year, discontinuation of MTX was compared between patients with and without MTX intolerance.

RESULTS

MISA score had a good predictive ability (area under the curve [AUC] of 0.904), with sensitivity and specificity of 91.4% and 84.3% (cut-off ≥1) to correctly classify MTX intolerance and was better than MISS score (AUC of 0.823). Among 414 RA patients, 159 (38.4%) had MTX intolerance, with common symptoms being nausea, lethargy, irritability and loss of appetite. On multivariable analysis, age (odds ratio 0.972) and body mass index (odds ratio 1.061) were significant predictors of MTX intolerance. At 1 year, a higher proportion of patients with intolerance than without intolerance had discontinued MTX (odds ratio 2.4, P = 0.02). To classify severity of intolerance, another score, MISA-cross-product, was developed and validated, with an AUC of 0.899.

CONCLUSIONS

The newly developed MISA questionnaire and score had good predictive ability to diagnose MTX intolerance. Intolerance to MTX was common, being found in one-third of RA patients. Patients with intolerance were twice more likely to discontinue MTX at 1 year.

The Therapeutic Landscape of Rheumatoid Arthritis: Current State and Future Directions

Rheumatoid arthritis (RA) is a debilitating autoimmune disease with grave physical, emotional and socioeconomic consequences. Despite advances in targeted biologic and pharmacologic interventions that have recently come to market, many patients with RA continue to have inadequate response to therapies, or intolerable side effects, with resultant progression of their disease. In this review, we detail multiple biomolecular pathways involved in RA disease pathogenesis to elucidate and highlight pathways that have been therapeutic targets in managing this systemic autoimmune disease. Here we present an up-to-date accounting of both emerging and approved pharmacological treatments for RA, detailing their discovery, mechanisms of action, efficacy, and limitations. Finally, we turn to the emerging fields of bioengineering and cell therapy to illuminate possible future targeted therapeutic options that combine material and biological sciences for localized therapeutic action with the potential to greatly reduce side effects seen in systemically applied treatment modalities.

Usefulness of daily folic acid supplementation during methotrexate treatment of Japanese patients with rheumatoid arthritis

OBJECTIVES

We investigated the effect of daily folic acid supplementation on methotrexate (MTX) toxicity and efficacy in Japanese patients with rheumatoid arthritis (RA).

METHODS

We followed 19 patients treated with MTX who switched from taking weekly 5 mg folic acid supplementation (weekly regimen) to 1.25 mg daily (daily regimen). White blood cell (WBC) and platelet (PLT) counts, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels were collected for 24 weeks following the change.

RESULTS

We observed no significant changes in WBC or PLT counts. AST and ALT levels, which had exceeded the upper limits of their normal ranges at the beginning of the study, were improved significantly at weeks 4 and 8, no subsequent deterioration in liver function was found. Further, no significant changes in ESR and CRP levels were observed.

CONCLUSION

Our data indicate that supplementing 1.25 mg of folic acid daily rather than 5 mg weekly reduces toxicity caused by MTX without affecting its efficacy.

Effectiveness of methotrexate in moderate to severe psoriasis patients: real-world registry data from the Swiss Dermatology Network for Targeted Therapies (SDNTT)

Methotrexate (MTX) is a frequently used anti-psoriatic drug that is commonly recommended in international psoriasis guidelines. It is effective in treating skin lesions, nail changes and psoriatic arthritis. In 2017 a prospective, multicenter, randomized, double-blind, placebo-controlled, phase 3 trial, commonly known as the METOP trial, was published assessing the effectiveness and safety of subcutaneous administration of methotrexate. Because trial data do not always relate to real-life data with unselected patient populations, we wanted to determine whether the data obtained in the METOP-trial correspond to real-life registry data from our Swiss Dermatology Network for Targeted Therapies (SDNTT). Data of 449 patients with moderate to severe psoriasis who participated in the SDNTT registry between 2011 and 1st of July 2017 were analyzed. Only patients receiving methotrexate s.c. were included. 66 patients under MTX were included into this study. Baseline PASI was 6.3 ± 3.8 (SDNTT) compared to 15.9 ± 5.9 in the METOP trial. In our cohort, only 18% of all patients reached PASI 75 after 12 weeks, 6% showed a complete remission (PASI 100) compared to 41% and 4% in the METOP trial after 16 weeks. 22.7% of all patients showed increased liver enzymes in either study and nausea was seen in 15% (SDNTT) versus 22% (METOP) of patients. No severe adverse events were observed in our cohort. Compared to the METOP-trial, the response rates seen our real-world cohort were distinctly lower.

Polymorphism in Organic Anion-Transporting Polypeptide Gene Related to Methotrexate Response in Rheumatoid Arthritis Treatment

BACKGROUND

Methotrexate (MTX) is still the first-choice drug for the treatment of rheumatoid arthritis (RA). In Japan, MTX doses of up to 16 mg/week were approved in 2011. In this study, we aimed to identify the gene polymorphisms that can predict therapeutic effects of MTX in Japanese patients in current clinical settings.

METHODS

This study involved 171 patients with RA (all Japanese nationals, age 63.5±10.0 years) who had been administered MTX. The analyzed polymorphisms included 82 single nucleotide polymorphisms (SNPs) involved in the MTX pharmacological pathway or in the pathogenesis of RA. Responders were patients who showed high sustained remission or low disease activity with MTX or conventional disease-modifying anti-rheumatic drugs (DMARDs) treatment beyond 6 months. Non-responders were patients who showed moderate or high disease activity, who were prescribed biological DMARDs. A logistic model was constructed with Responder/Non-responder as the target variable, and minor allele frequency was set as an explanatory variable.

RESULTS

None of the 82 SNPs targeted for analysis met the Bonferroni significance threshold of 6.098×10^-4. However, we identified SLCO1B1 rs11045879 as an SNP that might yield significant results if the number of patients were to be increased (P=0.015).

CONCLUSIONS

The rs11045879 minor allele in the SLCO1B1 gene is a potential predictor of non-responders to MTX treatment among Japanese RA patients. In future collaborative research, we will investigate whether the association with SLCO1B1 polymorphism is significant by performing statistical analysis with a larger study population.

Plasma Leptin Does Not Reflect the Effect of High Body Mass Index on Disease Activity in Rheumatoid Arthritis

Background: The effect of obesity on disease severity in rheumatoid arthritis (RA) remains controversial. Adipocytes secrete pro-inflammatory cytokines and adipokines which may contribute to RA disease activity. The goal of the present study is to address the association between body mass index (BMI) with plasma levels of leptin, pro-inflammatory cytokines, and RA disease severity.Methods: Fifty RA patients (20 newly diagnosed and 30 under treatment) as well as 30 age- and sex-matched healthy subjects were included in this survey. The plasma levels of leptin and pro-inflammatory cytokines, including TNF-α and IL-6, were measured, and the results were compared among the patients in the three different categories of BMI, including <25, ≥25-30, and ≥30.Results: In our study, a significant positive correlation was observed between disease activity score-28 (DAS-28) and BMI in overweight (OW) RA patients (p = .036 r = 0.440). The plasma levels of leptin were significantly higher in patients group, compared to healthy subjects (p < .05); moreover, leptin levels were significantly higher in OW and obese patients compared to RA patients with normal BMI (p = .011, p = .001, respectively) and also BMI had positive correlation with leptin concentrations just in the newly diagnosed patients (p < .0001, r = 0.748). There was no correlation between leptin and DAS-28. The plasma IL-6 and TNF-α did not show significant differences between RA patients and healthy subjects, and also the plasma leptin did not have any correlation with plasma levels of IL-6 and TNF-α.Conclusion: BMI contribution to RA disease severity is independent of systemic levels of leptin and pro-inflammatory cytokines.

Effects of the Cathepsin K Inhibitor ONO-5334 and Concomitant Use of ONO-5334 with Methotrexate on Collagen-Induced Arthritis in Cynomolgus Monkeys

We examined whether the cathepsin K inhibitor, ONO-5334, administered alone or in combination with methotrexate (MTX), could ameliorate joint destruction evoked by collagen-induced arthritis (CIA) in female cynomolgus monkeys. CIA was induced by immunizing with bovine type II collagen. ONO-5334 (30 mg/kg/day) was orally administered once daily and MTX (10 mg/body/day) twice weekly for 9 weeks. X-ray (evaluation of joint destruction) and swelling (inflammatory) scores of proximal interphalangeal (PIP), distal interphalangeal (DIP), and metacarpophalangeal (MP) joints were evaluated. Urinary concentrations of C-terminal telopeptide of type I collagen (CTX-I) and type II collagen (CTX-II) were measured. Arthritis, accompanied by bone and cartilage destruction, was successfully induced in this collagen-induced arthritis monkey model. ONO-5334 showed no suppressive effect on joint swelling, while the joint swelling scores in the MTX and combination (ONO-5334 + MTX) groups were less than 50% compared with the control group. ONO-5334 decreased X-ray score by a mean of 64% (p<0.05 vs the control group), and MTX also decreased in X-ray score by a mean of 46% but with no statistical significance. Combination of ONO-5334 and MTX further decreased the X-ray score by 28% over MTX group (74% reduction vs the control group, p<0.01). Maximum increase in CTX-I (10-fold) and CTX-II (7-fold) compared to baseline was observed at 7 and 3 weeks after the first sensitization, respectively. After treatment with ONO-5334 alone or in combination with MTX, concentrations were maintained near baseline for both markers. In conclusion, ONO-5334 prevented joint destruction but not joint inflammation in this monkey CIA model. Concomitant use of ONO-5334 with MTX reduced architectural joint destruction compared to MTX alone; therefore, ONO-5334 may help to prevent joint destruction in combination with MTX for the treatment of rheumatoid arthritis.

Clinical predictors of inadequate response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) including methotrexate (MTX) in untreated rheumatoid arthritis patients: A single-center observational study

Objectives: To investigate predictors of inadequate response to first conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) including methotrexate (MTX) in untreated rheumatoid arthritis (RA) patients in daily clinical practice.Methods: Inadequate response to MTX or other csDMARDs was defined as being not low disease activity at 12 months in more than 3 of 4 composite measures, and discontinuation or start of biologic DMARDs. The association between baseline factors and csDMARDs-IR was assessed by univariate and multivariate logistic regression analyses.Results: Four hundred and eleven and 146 patients were started on MTX and other csDMARDs, respectively; 218 patients were responsive to MTX, with a response rate of 47.0%. Tender joint count (TJC, ≥6 in 28joints, odds ratio [OR] = 1.67, 95% confidence interval [CI] 1.06-2.64) and CRP (≥1.0 mg/dL, OR = 1.72, 95%CI: 1.10-2.70) at baseline were identified as predictors on multivariate logistic regression analysis. TJC (OR = 3.60, 95%CI: 1.29-10.00) was the factor identified as a predictor of the development of other csDMARDs-IR.Conclusion: In this observational study, patients with untreated RA at risk of inadequate response to MTX included those with a higher TJC and higher CRP, while a higher TJC was the only independent predictor of an inadequate response to csDMARDs other than MTX.

CD39 positive regulatory T cell frequency as a biomarker of treatment response to methotrexate in rheumatoid arthritis

AIM

Nearly one-third of patients with rheumatoid arthritis (RA) do not respond to Methotrexate (MTX), the first-line therapy in RA. CD39, an ectonucleotidase highly expressed on regulatory T cells (Tregs), is responsible for production of adenosine, an important anti-inflammatory mediator of MTX action. Higher expression of CD39 on Tregs improves their suppressive capacity. Therefore, we aimed to study the role of CD39⁺ Treg frequency as a biomarker for MTX treatment response in RA.

METHODS

Patients with active RA who were naive to disease-modifying anti-rheumatic drugs were enrolled. Frequencies of CD39⁺ Tregs (CD4⁺ CD25⁺ FoxP3⁺ CD39⁺ cells) and CD4⁺ CD25⁺ CD39⁺ cells were determined by flow cytometry in peripheral blood before the start of therapy. After 4 months of MTX monotherapy, patients were classified into responders (European League Against Rheumatism [EULAR] good/moderate response) and non-responders (EULAR no response). All samples were genotyped for single nucleotide polymorphisms (SNPs) rs11188513 and rs7071836 in the ENTPD1 (CD39) gene.

RESULTS

After 4 months of MTX monotherapy, 54 patients were classified as responders and 16 as non-responders. The baseline CD39⁺ Treg and CD4⁺ CD25⁺ CD39⁺ cell frequencies were significantly higher in the responder group as compared with the non-responder group (P < 0.05 and P < 0.01, respectively). AA genotype at SNP rs7071836 was associated with poor response to MTX (P < 0.05; odds ratio = 5.67; 95% CI = 1.12-28.75).

CONCLUSION

Higher frequencies of CD39⁺ Tregs and CD4⁺ CD25⁺ CD39⁺ cells in the peripheral blood are associated with response to MTX in RA and hence, these could be considered as potential biomarkers for prediction of response to MTX treatment.

Expand the differential…think beyond rheumatoid arthritis

A 31-year-old male patient with severe, migratory arthralgias presented to our academic medical centre after being erroneously diagnosed and treated for rheumatoid arthritis for over 1 year. Multiple immunomodulatory therapies for rheumatoid arthritis were attempted with no relief of symptoms. Eventually, the pain was so bothersome that the patient became bedridden for 1 month prior to presenting to our facility. Our assessment revealed that the patient met the diagnostic criteria, known as the Yamaguchi criteria, needed to diagnose adult-onset Still's disease. Yamaguchi criteria include migratory inflammatory arthritis, quotidian fevers, leucocytosis and a salmon-coloured maculopapular rash. These signs and symptoms may go unnoticed or overlooked if adult-onset Still's disease is not considered. The patient was treated with anakinra (a recombinant human IL-1 receptor antagonist) and had rapid improvement in his symptoms, with the restoration of mobility.

Side effects of methotrexate therapy for rheumatoid arthritis: A systematic review

Methotrexate (MTX) is used as an anchor disease-modifying anti-rheumatic drugs (DMARDs) in treating rheumatoid arthritis (RA) because of its potent efficacy and tolerability. MTX benefits a large number of RA patients but partially suffered from side effects. A variety of side effects can be associated with MTX when treating RA patients, from mild to severe or discontinuation of the treatment. In this report, we reviewed the possible side effects that MTX might cause from the most common gastrointestinal toxicity effects to less frequent malignant diseases. In order to achieve regimen with less side effects, the administration of MTX with appropriate dose and a careful pretreatment inspection is necessary. Further investigations are required when combining MTX with other drugs so as to enhance the efficacy and reduce side effects at the same time. The management of MTX treatment is also discussed to provide strategies for occurred side effects. Thus, this review will provide scholars with a comprehensive understanding the side effects of MTX administration by RA patients.

Impact of the Adalimumab Patient Support Program's Care Coach Calls on Persistence and Adherence in Canada: An Observational Retrospective Cohort Study

PURPOSE

Adalimumab (ADA) is a tumor necrosis factor-α inhibitor indicated for use in various immune-mediated inflammatory diseases. Patients receiving ADA in Canada are eligible to enroll in the AbbVie Care's Patient Support Program (PSP), which provides personalized services, including tailored interventions in the form of nurse-provided care coach calls (CCCs), with the goal of improving patients' experiences and outcomes. The primary objective of this study was to evaluate the impact of PSP services, including CCCs and patient characteristics, on persistence with and adherence to ADA for those patients enrolled in the PSP. A secondary objective was to estimate the effect of initial CCCs on treatment-initiation abandonment (ie, failure to initiate therapy after enrollment in the PSP).

METHODS

An observational retrospective cohort study was conducted. A patient linkage algorithm based on probabilistic matching was developed to link the AbbVie Care PSP database to the QuintilesIMS longitudinal pharmacy transaction database. Patients who started ADA therapy between July 2010 and August 2014 were selected, and their prescriptions were evaluated for 12 months after the date of ADA start to calculate days until drug discontinuation, that is, the end of persistence, defined as >90 days without therapy. Cox proportional hazards modeling was used for estimating hazard ratios for the association between persistence and patient characteristics and each PSP service. Adherence, measured by medication possession ratio, was calculated, and multivariate logistic regression provided adjusted odds ratios for the relationship between being adherent (medication possession ratio ≥80%) and patient characteristics and each PSP service. Treatment-initiation abandonment among patients who received an initial CCC compared with those who did not was analyzed using the χ² test.

FINDINGS

Analysis of 10,857 linked patients yielded statistically significant differences in the hazard ratio of discontinuation and the likelihood of being adherent across multiple variables between patients who received CCCs in comparison to patients who did not. Patients receiving CCCs were found to have a 72% decreased risk for therapy discontinuation (hazard ratio = 0.282; P < 0.0001), and a greater likelihood of being adherent (odds ratio = 1.483; P < 0.0001), when compared with those patients who did not receive CCCs. The rate of treatment-initiation abandonment was significantly higher in patients who did not receive initial CCCs (P < 0.0001).

IMPLICATIONS

Ongoing CCCs, provided by AbbVie Care PSP, were associated with greater patient persistence and adherence over the first 12 months of treatment, while initial CCCs were associated with a lower rate of treatment-initiation abandonment. Results may inform the planning of interventions aimed at improving treatment adherence and patient outcomes.

Calprotectin in patients with chronic rheumatoid arthritis correlates with disease activity and responsiveness to methotrexate

OBJECTIVE

Calprotectin (myeloid-related protein 8/14) is elevated in inflammatory diseases and a correlation of serum calprotectin and disease activity in rheumatoid arthritis (RA) has been shown. In this study, we investigated plasma calprotectin as a disease marker in patients with chronic RA treated with methotrexate (MTX) monotherapy and compared plasma calprotectin with C-reactive protein (CRP) in this matter.

METHODS

Seventy-six patients with chronic RA were included in this open prospective study and of these 40 were included prior to initiation of MTX therapy. The patients were followed with laboratory and clinical parameters for 52-56 weeks. Plasma calprotectin was analyzed at the start of study and at various intervals. Radiographic evaluation was performed at baseline and after 17.2 months and progression in joint destruction was measured with Larsen score. The response to MTX was evaluated according to the American College of Rheumatology criteria.

RESULTS

Patients starting MTX treatment had significantly higher levels of plasma calprotectin compared to patients well established on MTX therapy (p = .008). Among the 40 patients naive to MTX, 25 responded to MTX therapy and serum calprotectin decreased significantly in these patients (p = .0007). The radiographic damage showed no relation to calprotectin.

CONCLUSIONS

Plasma calprotectin is associated with disease activity in patients with chronic RA and is more strongly correlated to MTX response compared to CRP. The role of calprotectin as a disease marker is promising and the advantages compared to CRP needs to be further investigated.

Moving toward personalized medicine in rheumatoid arthritis: SNPs in methotrexate intracellular pathways are associated with methotrexate therapeutic outcome

AIM

Evaluate the potential of selected SNPs as predictors of methotrexate (MTX) therapeutic outcome.

PATIENTS & METHODS

In total, 35 SNPs in 14 genes involved in MTX intracellular pathways and Phase II reactions were genotyped in 233 rheumatoid arthritis (RA) patients treated with MTX. Binary logistic regressions were performed by genotype/haplotype-based approaches. Non-Response- and Toxicity-Genetic Risk Indexes (Non-RespGRI and ToxGRI) were created.

RESULTS

MTX nonresponse was associated to eight genotypes and three haplotypes: MTHFR rs1801131 AA and rs1801133 TT; MS rs1805087 AA; MTRR rs1801394 A carriers; ATIC rs2372536 C carriers, rs4673993 T carriers, rs7563206 T carriers and rs12995526 T carriers; CC for GGH rs3758149 and rs12681874; CGTTT for ATIC combination 1; and CTTTC for ATIC combination 2. From overall Non-RespGRI patients with indexes 6-8 had more than sixfold increased risk for MTX nonresponse than those patients with indexes 0-5. MTX-related toxicity was associated to five genotypes and two haplotypes: ATIC rs2372536 G carriers, rs3821353 T carriers, rs7563206 CC and rs12995526 CC; ADORA2A rs2267076 T; CTTCC for ATIC combination 1; and TC for ADORA2A rs2267076 and rs2298383. From overall ToxGRI, patients with indexes 3-4 had more than sevenfold increased risk for MTX-related toxicity than those patients with indexes 1-2.

CONCLUSION

Genotyping may be helpful to identify which RA patients will not benefit from MTX treatment and, consequently, important to personalized medicine in RA. Nevertheless, further studies are required to validate these findings.

Preliminary study for predicting better methotrexate efficacy in Japanese patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic inflammatory status, joint destruction, disability, and pain. Methotrexate (MTX) has been confirmed to reduce disease activity and delay or stabilize the development of bone erosions. However, major drawbacks are that patients show great interindividual variability in response to MTX and the unpredictable occurrence of side effects. A strategy for personalized MTX treatment to predict its efficacy and toxicity has not yet been determined. To establish personalized MTX therapy in Japanese patients with rheumatoid arthritis, we performed a preliminary study for predicting better methotrexate efficacy including single-nucleotide polymorphisms (SNPs) for MTX-related transporters/enzymes.

METHODS

Disease control status (good or poor) was judged by the number of Disease Activity Scores (DAS28) of <2 for 6-12 months. The response index R was calculated by the improved area under the curve (AUC) of the DAS28 score for 0-3 or 0-6 months by dividing the cumulative dose of MTX during 0-3 or 0-6 months, respectively. Genotyping of alleles of RFC1 80G > A, RFC1 -43 T > C, FPGS 1994G > A, GGH 401C > T, MTHFR 1298A > C, and TYMS 3'-UTR (-6/+6) was performed using the real-time PCR system.

RESULTS

Seven of 21 patients were judged as good responders in terms of disease control, and the remainder as poor responders. For 0-3 months after starting MTX administration, the median cumulative dose and improved DAS28 AUC in the good and poor response groups were 96.0 mg and 25.4 and 118.0 mg and 23.4, respectively. For 0-6 months, the median cumulative dose and improved DAS28 AUC in the good and poor response groups were 192.0 mg and 51.0 and 214.0 mg and 47.6, respectively. Statistically significant differences between the 2 groups in the 0-6-month period were observed in DAS28 AUC improvement and index R. A slight tendency for a correlation between G/G genotypes and A allele genotypes in RFC1 80 genotypes was observed, although it did not reach statistical significance.

CONCLUSION

This study suggested that aggressive RA treatment with MTX from the early period of administration is necessary to obtain a good response after 6 months, although no SNPs predicting a better treatment response to MTX were identified.

Reduction in Serum Uric Acid May Be Related to Methotrexate Efficacy in Early Rheumatoid Arthritis: Data from the Canadian Early Arthritis Cohort (CATCH)

OBJECTIVES

The mechanism of action of methotrexate in rheumatoid arthritis (RA) is complex. It may increase adenosine levels by blocking its conversion to uric acid (UA). This study was done to determine if methotrexate lowers UA in early RA (ERA).

METHODS

Data were obtained from Canadian Early Arthritis Cohort, an incident ERA cohort. All ERA patients with serial UA measurements were included, comparing those with methotrexate use vs. no methotrexate exposure (controls). Analyses were exploratory. Patients with concomitant gout or taking UA-lowering therapies were excluded.

RESULTS

In total, 49 of the 2,524 ERA patients were identified with data available for both pre-methotrexate UA levels and post-methotrexate UA levels (300 µmol/L and 273 µmol/L, respectively; P = 0.035). The control group not taking methotrexate had a mean baseline UA level of 280 µmol/L and a follow-up level of 282 µmol/L (P = 0.448); mean change in UA with methotrexate was −26.8 µmol/L vs. 2.3 µmol/L in the no methotrexate group (P = 0.042). Methotrexate users with a decrease in UA had a disease activity score of 2.37 for 28 joints when compared with the controls (3.26) at 18 months (P = 0.042). Methotrexate users with decreased UA had a lower swollen joint count (SJC) of 0.9 at 18 months, whereas methotrexate users without lowering of UA had an SJC of 4.5 (P = 0.035). Other analyses were not significant.

CONCLUSIONS

Methotrexate response is associated with lowering of serum UA in ERA compared to nonusers. This may be due to changes in adenosine levels. Methotrexate response is associated with lower UA and fewer swollen joints compared to nonresponders.

Myeloid-related Protein 8/14 Levels in Rheumatoid Arthritis: Marker of Disease Activity and Response to Methotrexate

Objective.

Myeloid-related proteins (MRP) 8/14 belong to a family of calcium-binding proteins produced by myeloid cells. Baseline serum levels of MRP8/14 have been shown to predict response to biologicals in rheumatoid arthritis (RA). Because methotrexate (MTX) is the first-line therapy in RA, we studied whether MRP8/14 levels can predict response to MTX.

Methods.

Patients with active RA disease who were naive to disease-modifying antirheumatic drugs were enrolled. All patients were treated with MTX only, to a maximum of 25 mg/week or the maximal tolerated dose. At 4 months, the European League Against Rheumatism response was assessed. All patients who needed rescue therapy after 2 months or who did not respond at 4 months were classified as nonresponders.

Results.

Ninety patients were enrolled, of whom 3 discontinued MTX within 4–6 weeks, so 87 patients were analyzed [74 women, median (interquartile range; IQR) for the Disease Activity Score at 28 joints (DAS28) was 4.43 (4.1–5.1)]. The median (IQR) serum MRP8/14 level at baseline was 19.95 µg/ml (11.49–39.06). The serum MRP8/14 had good correlation with DAS28-C-reactive protein (CRP; r = 0.35, p = 0.001). The MRP8/14 levels fell significantly after 4 months of treatment (10.28 µg/ml, 5.95–16.05, p < 0.001). Among 87 patients, 69 were responders. The median (IQR) baseline level of MRP8/14 was higher among responders compared with nonresponders: 23.99 µg/ml (15.39–42.75) versus 9.58 µg/ml (6.11–24.93, p = 0.00250). The levels declined in the responders, from 23.99 µg/ml (15.39–42.75) to 10.41 µg/ml (5.83–15.61, p < 0.001), but not in the nonresponders, from 9.58 µg/ml (6.11–24.93) to 9.19 µg/ml (7.74–21.96, p = 0.687). Receiver-operation characteristic analysis showed that MRP8/14 was a better predictor of response than CRP and erythrocyte sedimentation rate, especially with early disease onset (< 1-yr duration).

Conclusion.

MRP8/14 is a good marker of disease activity in RA, and higher levels predict response to MTX.

Methotrexate pharmacokinetic genetic variants are associated with outcome in rheumatoid arthritis patients

BACKGROUND

Methotrexate (MTX) is the most used drug for the treatment of rheumatoid arthritis (RA) although outcome differs among patients.

AIM

To evaluate whether polymorphisms in pharmacokinetic genes are associated with outcome in RA patients receiving MTX.

PATIENTS & METHODS

We analyzed 28 SNPs in SLC19A1/RFC1, ABCB1, FPGS and GGH genes.

RESULTS

We studied 194 RA patients receiving MTX monotherapy. Two FPGS SNPs, rs10987742 and rs10106, were associated with response (p = 0.033 and p = 0.041, respectively). The FPGS rs10106 variant was also associated with MTX survival (p = 0.005) and toxicity (p = 0.021). Three ABCB1 SNPs, rs868755, rs10280623 and rs1858923, were associated with toxicity (p = 0.025, p = 0.048 and p = 0.031, respectively).

CONCLUSION

FPGS and ABCB1 genetic variants can influence the outcome in RA patients receiving MTX monotherapy.

Methotrexate polyglutamates as a potential marker of adherence to long-term therapy in children with juvenile idiopathic arthritis and juvenile dermatomyositis: an observational, cross-sectional study

Introduction

Methotrexate (MTX) is a cornerstone of treatment in a wide variety of inflammatory conditions, including juvenile idiopathic arthritis (JIA) and juvenile dermatomyositis (JDM). However, owing to its narrow therapeutic index and the considerable interpatient variability in clinical response, monitoring of adherence to MTX is important. The present study demonstrates the feasibility of using methotrexate polyglutamates (MTXPGs) as a biomarker to measure adherence to MTX treatment in children with JIA and JDM.

Methods

Data were collected prospectively from a cohort of 48 children (median age 11.5 years) who received oral or subcutaneous (SC) MTX therapy for JIA or JDM. Dried blood spot samples were obtained from children by finger pick at the clinic or via self- or parent-led sampling at home, and they were analysed to determine the variability in MTXPG concentrations and assess adherence to MTX therapy.

Results

Wide fluctuations in MTXPG total concentrations (>2.0-fold variations) were found in 17 patients receiving stable weekly doses of MTX, which is indicative of nonadherence or partial adherence to MTX therapy. Age (P = 0.026) and route of administration (P = 0.005) were the most important predictors of nonadherence to MTX treatment. In addition, the study showed that MTX dose and route of administration were significantly associated with variations in the distribution of MTXPG subtypes. Higher doses and SC administration of MTX produced higher levels of total MTXPGs and selective accumulation of longer-chain MTXPGs (P < 0.001 and P < 0.0001, respectively).

Conclusions

Nonadherence to MTX therapy is a significant problem in children with JIA and JDM. The present study suggests that patients with inadequate adherence and/or intolerance to oral MTX may benefit from SC administration of the drug. The clinical utility of MTXPG levels to monitor and optimise adherence to MTX in children has been demonstrated.

Trial registration

ISRCTN Registry identifier: ISRCTN93945409. Registered 2 December 2011.

Pharmacogenomics of Methotrexate Membrane Transport Pathway: Can Clinical Response to Methotrexate in Rheumatoid Arthritis Be Predicted?

Background: Methotrexate (MTX) is widely used for rheumatoid arthritis (RA) treatment. Single nucleotide polymorphisms (SNPs) could be used as predictors of patients’ therapeutic outcome variability. Therefore, this study aims to evaluate the influence of SNPs in genes encoding for MTX membrane transport proteins in order to predict clinical response to MTX. Methods: Clinicopathological data from 233 RA patients treated with MTX were collected, clinical response defined, and patients genotyped for 23 SNPs. Genotype and haplotype analyses were performed using multivariate methods and a genetic risk index (GRI) for non-response was created. Results: Increased risk for non-response was associated to SLC22A11 rs11231809 T carriers; ABCC1 rs246240 G carriers; ABCC1 rs3784864 G carriers; CGG haplotype for ABCC1 rs35592, rs2074087 and rs3784864; and CGG haplotype for ABCC1 rs35592, rs246240 and rs3784864. GRI demonstrated that patients with Index 3 were 16-fold more likely to be non-responders than those with Index 1. Conclusions: This study revealed that SLC22A11 and ABCC1 may be important to identify those patients who will not benefit from MTX treatment, highlighting the relevance in translating these results to clinical practice. However, further validation by independent studies is needed to develop the field of personalized medicine to predict clinical response to MTX treatment.

Pain reduction with oral methotrexate in knee osteoarthritis, a pragmatic phase iii trial of treatment effectiveness (PROMOTE): study protocol for a randomized controlled trial

Background

Osteoarthritis (OA) is the fastest growing cause of disability worldwide. Current treatments for OA are severely limited and a large proportion of people with OA live in constant, debilitating pain. There is therefore an urgent need for novel treatments to reduce pain. Synovitis is highly prevalent in OA and is associated with pain. In inflammatory arthritides such as rheumatoid arthritis, methotrexate (MTX) is the gold standard treatment for synovitis and has a well-known, acceptable toxicity profile. We propose that using MTX to treat patients with symptomatic knee OA will be a practical and safe treatment to reduce synovitis and, consequently, pain.

Methods/Design

Pain Reduction with Oral Methotrexate in knee Osteoarthritis, a pragmatic phase III trial of Treatment Effectiveness (PROMOTE) is an investigator-initiated, multi-centre, randomized, double-blind, pragmatic placebo-controlled trial. A total of 160 participants with symptomatic knee OA will be recruited across primary and secondary care sites in the United Kingdom and randomized on a 1:1 basis to active treatment or placebo, in addition to usual care, for 12 months. As is usual practice for MTX, dosing will be escalated over six weeks to 25 mg (or maximum tolerated dose) weekly for the remainder of the study. The primary endpoint is change in average knee pain during the past week (measured on an 11-point numerical rating scale) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures. A health economics analysis will also be performed. A magnetic resonance imaging substudy will be conducted to provide an explanatory mechanism for associated symptom change by examining whether MTX reduces synovitis and whether this is related to symptom change. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis.

Discussion

The PROMOTE trial is designed to examine whether MTX is an effective analgesic treatment for OA. The MRI substudy will address the relationship between synovitis and symptom change. This will potentially provide a much needed new treatment for knee OA.

Trial registration

Current Controlled Trials identifier: ISRCTN77854383 (registered: 25 October 2013).

Personalized medicine in rheumatoid arthritis: is the glass half full or half empty?

The care of patients with rheumatoid arthritis (RA) has been revolutionized since the 1990s. Strict monitoring and disease control based on measurement of signs and symptoms towards a target of low disease activity have improved outcome of patients enormously. As a result of treatment strategies based upon individualized measurement of disease activity, the clinical view of RA has changed from a destructive autoimmune disease (with a median joint damage of >10 Sharp units per year) to a condition in which significant damage can be prevented in the majority of patients. Moreover, a large number of targeted therapies (tumour necrosis factor, IL6, CD80/CD86 and CD20 inhibitors) have become available to better treat the underlying disease process. However, identification of the underlying pathways that drive the disease process in an individual patient has been relatively unsuccessful, implying that no predictive factors have been identified to guide the choice of a specific treatment. Distinct subsets of RA patients have been identified, based on the presence or absence of anticitrullinated protein antibodies (ACPAs). These two subsets are associated with different environmental and genetic risk factors, histology and disease outcome (a more destructive disease course with more persistent joint inflammation is observed when ACPAs are present). Therefore, it is recommended that treatment should be guided towards a more consistently low level of disease activity in the presence of ACPAs than in the absence of the antibodies.

Antinociceptive and anti-arthritic effects of kramecyne

AIMS

The aim of this study was to evaluate the antinociceptive (acute assays) and anti-inflammatory (chronic assays) effects of kramecyne (KACY), a peroxide isolated from Krameria cytisoides.

MAIN METHODS

The antinociceptive activity of KACY was evaluated using the hot plate, acetic acid and formalin tests. The effects of KACY on heat-induced hemolysis in rat erythrocytes were also evaluated. The in vivo anti-inflammatory assays were performed using the chronic TPA (12-O-tetradecanoylphorbol 13-acetate) method to induce ear edema and carrageenan-kaolin induced arthritis (CKIA). In the CKIA model, the hot plate test was performed, serum samples were obtained for the quantitation of pro-inflammatory (IL-1β, IL-6, IL-12 and TNF-α) and anti-inflammatory (IL-4 and IL-10) cytokines.

KEY FINDINGS

KACY possess antinociceptive effects with comparable activity to naproxen (NPX). KACY inhibited hemolysis (EC50 = 180 μg/mL), in comparison to the untreated group and with a higher potency than NPX (EC50 = 263 μg/mL). KACY at 50 mg/kg decreased inflammation by 38% (chronic TPA-induced edema model) and by 26% (CKIA model), in comparison with the vehicle group and with similar activity to the positive controls 8 mg/kg indomethacin (IND) and 1 mg/kg methotrexate (MTX), respectively. In the CKIA model, KACY increased the release of anti-inflammatory (IL-4 and IL-10) cytokines but reduced the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-12 and TNF-α). KACY at 50 and 100 mg/kg showed antinociceptive effects by 27% and 23%, respectively, in mice with mono-arthritis.

SIGNIFICANCE

KACY might be a good alternative for the treatment of rheumatoid arthritis (RA) due its antinociceptive and anti-inflammatory activities.

Therapeutic options after treatment failure in rheumatoid arthritis or spondyloarthritides

The prognosis for patients with rheumatoid arthritis or spondyloarthritides has improved dramatically due to earlier diagnosis, recognition of the need to treat early with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), alone or in combinations, the establishment of treatment targets, and the development of biological DMARDs (bDMARDs). Many patients are now able to achieve clinical remission or low disease activity with therapy, and reduce or eliminate systemic corticosteroid use. Guidelines recommend methotrexate as a first-line agent for the initial treatment of rheumatoid arthritis; however, a majority of patients will require a change of csDMARD or step up to combination therapy with the addition of another csDMARD or a bDMARD. However, treatment failure is common and switching to a different therapy may be required. The large number of available treatment options, combined with a lack of comparative data, makes the choice of a new therapy complex and often not evidence based. We summarize and discuss evidence to inform treatment decisions in patients who require a change in therapy, including baseline factors that may predict response to therapy.

Polymorphisms in genes involved in the mechanism of action of methotrexate: are they associated with outcome in rheumatoid arthritis patients?

Background: Methotrexate (MTX) is the first-line treatment option for newly diagnosed rheumatoid arthritis (RA) patients. However, 50–70% of the patients respond to treatment and 30% suffer toxicity. Aim: To identify pharmacogenetic markers of outcome in RA patients treated with MTX. Patients & methods: We analyzed 27 genetic variants in DHFR, TYMS, MTHFR, ATIC and CCND1 genes. Results: We included 124 RA patients treated with MTX monotherapy. In multivariate analyses two variants in the MTHFR gene were associated with response, rs17421511 (p = 0.024) and rs1476413 (p = 0.0086), as well as one in the DHFR gene, rs1643650 (p = 0.026). The ATIC rs16853826 variant was associated with toxicity (p = 0.039). Conclusion: MTHFR, DHFR and ATIC genetic variants can be considered as pharmacogenetic markers of outcome in RA patients under MTX monotherapy.

Original submitted 10 January 2014; Revision submitted 28 March 2014

Methotrexate induced pancytopenia

The well-reported methotrexate (MTX) toxicities are based on the duration and cumulative dosing of drug. The typical toxicities can be predicted by the timing of drug administration, where mucositis occurs as an earlier effect, while myelosuppression and the sequelae of pancytopenia occur later after MTX administration. Despite these well-known toxicities, low dose MTX therapy can become problematic, in particular with the elderly, who are at a greater risk for significant myelosuppression. We present a case of a 73-year-old female with pancytopenia causing severe neutropenia, mucocutaneous bleeding, and bruising and requiring intravenous antibiotic therapy and limited transfusion dependence as a result of low dose daily MTX for rheumatoid arthritis.

Changing incidence of orthopedic surgery in rheumatic disease: contributing factors

Rheumatic diseases are multisystem conditions that predominantly affect the musculoskeletal system, leading to soft tissue and articular damage. Historically, medical therapy was able to slow, but not prevent, erosion and joint destruction, resulting in the frequent need for orthopedic procedures to maintain function and minimize pain. However, the widespread use of disease-modifying anti-rheumatic drugs (DMARDs) and biologic therapy over the last twenty years has resulted in a dramatic decrease in the incidence of musculoskeletal damage and impairment among these patients. This review will discuss changing patterns of orthopedic surgery among patients with rheumatic diseases, focusing on rheumatoid arthritis and systemic lupus erythematosus.

An inhibitor of cathepsin K, icariin suppresses cartilage and bone degradation in mice of collagen-induced arthritis

The collagenase cathepsin K has been shown important in the pathogenesis of rheumatoid arthritis (RA). Icariin is the major pharmacologically active flavonol diglycoside of Herba Epimedii, an herb used in Chinese traditional medicine to treat arthritis. We investigated whether icariin can inhibit the protease activity of cathepsin K and its effects on a murine model of collagen-induced arthritis (CIA). Six-week old female BALB/C mice were immunized with type II collagen and treated with vehicle alone icariin (25mg/kg) for 21 days; a control remained untreated. Serum concentrations of type I collagen C-terminal telopeptide (CTX-I) and cartilage oligomeric matrix protein (COMP) and urinary concentrations of deoxypyridinoline (DPD) were measured, and disease severity was assessed. Compared with immunized, untreated mice, immunized icariin-treated mice had significantly lower urinary DPD (~25%, p<0.01) and serum COMP (~11.9%, p<0.01) concentrations, with serum CTX-1 (RatLaps) concentrations being significantly lower in immunized, icariin treated mice than in immunized, vehicle treated (p<0.01) and non-immunized (p<0.005) mice. Icariin also reduced the clinical signs of arthritis. Icariin inhibited cathpesin K activity in vitro and was effective in a mouse model of CIA similar to human RA, suggesting that this agent may have promise in the treatment of patients with RA.

Low-dose methotrexate results in the selective accumulation of aminoimidazole carboxamide ribotide in an erythroblastoid cell line

Therapeutic and toxic response to low-dose methotrexate (MTX) in the treatment of autoimmune disease continues to be highly variable, resulting in a critical need to identify predictive biomarkers of response. Biomarker development has been hampered by an incomplete understanding of the molecular pharmacology of low-dose MTX. To address this issue, accumulation of the substrates for aminoimidazole carboxamide ribonucleotide transformylase (AICART) and thymidylate synthase (TS) was measured as markers of pharmacological activity of MTX in an erythroblastoid cell line. A 115-fold increase in the AICART substrate and anti-inflammatory mediator, 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranosyl 5'-monophosphate (ZMP), was observed following exposure to 10 nM MTX but subsequently decreased with increasing MTX concentrations, declining to baseline levels with 1000 nM MTX. In contrast, the TS substrate, 2'-deoxyuridine 5'-monophosphate disodium salt (dUMP), displayed concentration-dependent accumulation, increasing 29-, 342-, and 471-fold over baseline with 10, 100, and 1000 nM MTX, respectively. Cellular levels of dUMP correlated with levels of the parent drug (MTX-PG1; r = 0.66, P < 0.001) and its polyglutamates (MTX-PG2-6) (r = 0.81, P < 0.001), whereas cellular levels of ZMP were only moderately correlated with MTX-PG1 (r = 0.34, P < 0.01). In contrast, accumulation of ZMP at 10 nM MTX was associated with a 2.9-fold increase in the AICART inhibitor dihydrofolate (DHF), represented primarily by long-chain DHF polyglutamates. Selectivity, defined as the ratio of ZMP to dUMP, was maximal following exposure to 6 nM MTX. Characterizing the range of MTX concentrations that selectively promote ZMP accumulation while preserving pyrimidine biosynthesis may lead to optimization of low-dose MTX therapy.

Old drugs, old problems: where do we stand in prediction of rheumatoid arthritis responsiveness to methotrexate and other synthetic DMARDs?

Methotrexate (MTX) is the central drug in the management of rheumatoid arthritis (RA) and other immune mediated inflammatory diseases. It is widely used either in monotherapy or in association with other synthetic and biologic disease modifying anti-rheumatic drugs (DMARDs). Although comprehensive clinical experience exists for MTX and synthetic DMARDs, to date it has not been possible to preview correctly whether or not a patient will respond to treatment with these drugs. Predicting response to MTX and other DMARDs would allow the selection of patients based on their likelihood of response, thus enabling individualized therapy and avoiding unnecessary adverse effects and elevated costs. However, studies analyzing this issue have struggled to obtain consistent, replicable results and no factor has yet been recognized to individually distinguish responders from nonresponders at treatment start. Variables possibly influencing drug effectiveness may be disease-, patient- or treatment-related, clinical or biological (genetic and nongenetic). In this review we summarize current evidence on predictors of response to MTX and other synthetic DMARDs, discuss possible causes for the heterogeneity observed and address its translation into daily clinical practice.

Leflunomide increases the risk of silent liver fibrosis in patients with rheumatoid arthritis receiving methotrexate

Introduction

We identified silent liver fibrosis in patients with rheumatoid arthritis (RA) using transient elastography, and investigated medication that correlated with abnormal liver stiffness measurement (LSM) values.

Methods

We consecutively enrolled 105 patients with RA taking methotrexate over 24 weeks with normal liver functions and no history of underlying chronic liver disease. Blood tests were performed, and body mass index and metabolic syndrome were assessed. We checked LSM values, and adopted 5.3 kPa as the cutoff for abnormal LSM values. The cumulative doses of medications including methotrexate, leflunomide, sulfasalazine, hydroxychloroquine, prednisolone, meloxicam, and celecoxib were calculated.

Results

The median age of patients (20 men and 85 women) was 52.4 years. The median LSM value was 4.7 kPa and 24 (22.9%) patients had abnormal LSM values. Gamma-glutamyltranspeptidase levels and the cumulative doses of leflunomide and prednisolone significantly correlated with LSM values (P<0.05). The cumulative dose of leflunomide, but not methotrexate, was significantly higher in patients with abnormal LSM values than that in patients with normal LSM values (P = 0.008). When RA patients receiving leflunomide plus methotrexate were classified into two groups according to the optimal cutoff cumulative dose of leflunomide (19,170 mg), abnormal LSM values were more frequently identified in patients with high cumulative dose of leflunomide (odds ratio, 12.750; P<0.001).

Conclusions

The cumulative dose of leflunomide was the only independent predictor of abnormal LSM values in patients with RA who had received methotrexate for more than six months.

Gene-gene interactions in folate and adenosine biosynthesis pathways affect methotrexate efficacy and tolerability in rheumatoid arthritis

OBJECTIVE

As no single nucleotide polymorphism has emerged as pivotal to predict the lack of efficacy and dose-limiting toxicities to methotrexate (MTX), we evaluated the contribution of gene-gene interactions to the effects of this prodrug in rheumatoid arthritis.

METHODS

A total of 255 patients treated with MTX for at least 3 months were evaluated with efficacy assessed using the European League Against Rheumatism response criteria or a physician's assessment of patient's response to MTX visual analog scale. Gastrointestinal and neurological idiosyncrasies were recorded in 158 patients. Fourteen single nucleotide polymorphisms in folate and adenosine biosynthesis pathways were measured and detection of gene-gene interactions was performed using multifactor-dimensionality reduction, a method that reduces high-dimensional genetic data into a single dimension of predisposing or risk-genotype combinations.

RESULTS

Efficacy to MTX (53% responders) was associated with high-order epistasis among variants in inosine-triphosphate pyrophosphatase, aminoimidazole-carboxamide ribonucleotide transformylase, and reduced folate carrier genes. In the absence of predisposing genotype combinations, a 3.8-fold lower likelihood of efficacy was observed (vs. in their presence, 95% confidence interval: 2.2-6.4; P<0.001). Increasing MTX polyglutamate concentrations tended to partially overcome this selective disadvantage. Idiosyncrasies occurred in 29% of patients. In the presence of risk-genotype combinations among variants in methylene tetrahydrofolate reductase, γ-glutamyl-hydrolase, thymidylate synthase, serine hydroxymethyltransferase, and inosine-triphosphate pyrophosphatase genes, an 8.9-fold higher likelihood to exhibit toxicities was observed (vs. in their absence, 95% confidence interval: 3.6-21.9; P<0.001). False-positive report probabilities were below 0.2, thereby indicating that true signals were likely detected in this cohort.

CONCLUSION

These data indicate that gene-gene interactions impact MTX efficacy and tolerability in rheumatoid arthritis.

Markers of treatment response to methotrexate in rheumatoid arthritis: where do we stand?

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug (DMARD) for the treatment of rheumatoid arthritis (RA). However, despite its efficacy and affordability, additional DMARDs or biologic agents are often required in order to achieve the recommended goals of low disease activity or remission. Although well tolerated by most, some patients develop important side effects such as cytopenias, gastrointestinal adverse events (stomatitis, nausea), or abnormal liver function tests, which may limit its use and may result in additional health care costs. Given the clinical implications of widespread use of MTX in RA, various studies have evaluated the role of potential biomarkers in predicting treatment effectiveness of MTX. These biomarkers include RBC MTX polyglutamate (PG) levels; genetic variation in genes from relevant biological and metabolic pathways; gene expression profiles; serum proteins. This paper provides an update on the current data regarding biomarkers of treatment response to MTX.