Methotrexate reduces withdrawal rates of TNF inhibitors due to ineffectiveness in rheumatoid arthritis but only in patients who are seropositive

The benefits of coprescribing methotrexate (MTX) with tumour necrosis factor (TNF)-inhibitors are well documented in rheumatoid arthritis (RA), though rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) status have not always been taken into account.1 Increasing doubt about the value of combination MTX and anti-TNF therapy in psoriatic arthritis2 3 led us to evaluate whether MTX reduced withdrawal rates due to ineffectiveness of anti-TNF therapy equally in seropositive and seronegative RA. Treatment durations for adalimumab or etanercept were analysed for 301 patients with RA using retrospective, real-world data from a single centre. All had started adalimumab or etanercept as a first-line biologic from 2003 onwards. Rates of ineffectiveness-related withdrawal during the first 5 years of anti-TNF therapy were analysed using Kaplan-Meier and Cox regression, with comparison of rates with respect to concomitant MTX at anti-TNF initiation. Fifty-two withdrawals for adverse events and 10 for other reasons constituted censored cases as did 136 still on anti-TNF at 5 years and 60 …