The role of concomitant methotrexate dosage and maintenance over time in the therapy of rheumatoid arthritis patients treated with adalimumab or etanercept: retrospective analysis of a local registry

Objective: To evaluate the pattern of prescription and maintenance over time of concomitant methotrexate (MTX), and its impact on a 2-year clinical response in a cohort of rheumatoid arthritis (RA) patients treated with a first-line tumor necrosis factor alpha inhibitor (TNFi). Patients and methods: The study population included all RA patients receiving adalimumab or etanercept a as first-line biologic drug, extracted from a local registry. Enrolled patients were stratified into 3 subgroups according to baseline concomitant MTX: no MTX, low-dose MTX (<= 10 mg/wk), and high-dose MTX ($12.5 mg/wk). The 2-year persistence of the initial MTX regimen was computed by the Kaplan-Meier method, and a Cox proportional hazard model was developed to examine potential predictors of MTX withdrawal/change of dosage. European League Against Rheumatism remission and good-to-moderate response were evaluated according to baseline MTX regimen and MTX maintenance over time. Results: A total of 330 patients (163 treated with adalimumab and 167 with etanercept) were included; 141 were prescribed TNFi without MTX and 112 received low-dose and 77 high-dose concomitant MTX. Male sex, younger age, and shorter mean disease duration were predictors of high-dose MTX use. Among MTX users (76.2% parenteral and 23.8% oral), initial MTX dose persisted over time in 79.9% at 1 year and 70.2% at 2 years. Fifty-one patients (27%) underwent MTX dose de-escalation/discontinuation because of intolerance/adverse events. The 2-year EULAR remission rate was higher in the patients receiving and maintaining high-dose MTX than in those receiving low-dose or no MTX (46.2% vs 29.5% and 23.4%, respectively; p=0.009). The same was true for good-to-moderate response rate (71.2% vs 52.6% and 50.4%, respectively; p=0.031). Conclusion: In a real-life setting, about one-third of RA patients treated with TNFis experienced dose reduction/discontinuation of concomitant MTX because of intolerance/adverse events over a 2-year follow-up period. Initial high-dose MTX and its maintenance over time are associated with better 2-year clinical response.