FRI0110 The impact of seropositivity on the effectiveness of abatacept versus tnf inhibitors in rheumatoid arthritis. real life data from several european registries (THE PAN-ABA STUDY)


Background Rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) are used as diagnostic tools, but may also be used as prognostic factors, as these biomarkers have been associated with better clinical responses to some biologic agents in rheumatoid arthritis (RA). Objectives To compare the impact of seropositivity on drug discontinuation and effectiveness for abatacept (ABA) and TNF inhibitors (TNFi) in patients (pts) with RA. Methods Pooled analysis of 13 observational RA registries from countries (FR, IT, CZ, DK, NO, PT, RO, ES, SE, CH, NL, JP, CA) where both ABA and TNFi were available concomitantly. Inclusion criteria were RA diagnosis, treatment with ABA or TNFi, and available RF or ACPA status. Main exposure was seropositivity: positive if RF or ACPA were positive, negative if both were negative, and missing if one was missing and the other was negative. Primary endpoint was drug discontinuation, analysed using Cox models, including treatment, seropositivity, and their interaction, adjusting for patient-, treatment-, and disease-characteristics, using strata terms for country and calendar year. We first tested for effect modification by country by additionally including an interaction term between treatment, seropositivity and country. Since we found no effect modification, we took out the interaction term. Effectiveness was analysed using DAS28 remission and low disease activity (LDA) at 1 year, corrected for attrition using Lundex1. Results Using data from 39 266 treatment-courses, in crude analyses, seronegativity was associated with higher drug discontinuation for pts on ABA but not on TNFi (p interaction 0.001), with a hazard ratio (HR) for seropositive vs seronegative of 0.74 (95%CI: 0.66–0.82) for pts on ABA and 0.96 (95%CI: 0.92–1.01) for pts on TNFi. On average, pts on ABA were older and had more prior bDMARDs. Adjusting for potential confounding factors did not modify the results qualitatively (figure 1), with significantly longer time before discontinuation in seropositive vs seronegative pts on ABA (adj. HR: 0.74 (95% CI: 0.67–0.84) but not on TNFi (adj. HR: 0.99 (95% CI: 0.94–1.04)).The proportion of pts reaching DAS28 remission or LDA at 1 year was significantly higher for seropositive vs seronegative pts on ABA (difference in proportion: remission: 5.0%; LDA: 9.7%), but similar for seropositive vs seronegative pts on TNFi (difference in proportion: remission: −2.7%; LDA: −2.3%). Conclusions Data from this large pooled registry suggests that seropositivity in RA pts is associated with increased drug retention and effectiveness for ABA but not for TNFi.Reference

Annals of the Rheumatic Diseases, 77 page 599–600