O24 Concomitant treatment with MTX does not increase the efficacy of ustekinumab or TFNi in PsA: results from the PsABio study

Abstract

Background: The additional benefit of methotrexate (MTX) as a concomitant treatment in PsA has not been fully elucidated for TNF inhibitors (TNFi) and no real-world data on this currently exist for ustekinumab (UST). We investigated the additive effect of MTX on the ability to reach composite treatment targets beyond monotherapy with UST or TNFi, and the ability to improve patient-reported outcomes in a real-world clinical setting in 8 European countries. Methods: The PsABio study (NCT02627768) evaluates persistence, effectiveness and tolerability of 1st, 2nd or 3rd-line UST or TNFi in patients with PsA. Proportions of patients reaching minimal disease activity (MDA)/very low disease activity (VLDA) and clinical Disease Activity in Psoriatic Arthritis (cDAPSA) low disease activity (LDA) or remission, as well as the patient acceptable symptom state (PASS; score ≤4) of the 12-item Psoriatic Arthritis Impact of Disease questionnaire (PsAID-12) were evaluated. Here we present 6-month follow-up data using intention to treat (ITT) analysis; patients who stopped/switched initial treatment were imputed as non-responders. The effect of MTX co-therapy was investigated within UST and TNFi cohorts, as well as between the cohorts, using multivariate logistic regression including interaction terms, and propensity score (PS) analysis to adjust for imbalanced, potentially prognostic, baseline covariates. Results: Of 930 patients, data was available for 868 ITT patients, including patients who switched/stopped before 6 months (UST: n=28/426 [6.6%], TNFi: n=44/442 [10.0%]). At baseline there were no relevant differences in demographics and disease activity, however there were significant differences in skin involvement as well as csDMARD and NSAID exposure. Co-therapy with MTX did not increase the likelihood of achieving any of the outcomes in either the UST or TNFi cohorts (Table 1). After PS adjustment, co-treatment with MTX did not influence treatment effects differently when added to UST compared with TNFi. concomitant use of csDMARDs other than MTX yielded very similar results. Conclusion: In a real-world setting, concomitant treatment with MTX in addition to UST or TNFi was not associated with enhanced effects across a broad variety of disease outcomes, including disease activity, disease impact, and skin involvement within or between treatment cohorts, after PS adjustment for baseline confounders.