SAT0178 Predictors of drug survival of abatacept in rheumatoid arthritis – results from a large national quality register cohort study

Background: Abatacept is a biologic disease modifying anti-rheumatic drug (bDMARD) used to treat rheumatoid arthritis (RA). There is growing experience with abatacept in many countries. National registers are useful resources for investigation of long term real world outcomes. Objectives: To compare the effectiveness of abatacept in the treatment of RA between bionaive patients and patients with previous bDMARD treatment, and to investigate predictors of remaining on treatment with abatacept. Methods: This was an observational cohort study, based on a national quality register database. Patients with a diagnosis of RA who initiated treatment with abatacept between April 1, 2006 and November 20, 2017, were included. Patients were censored at abatacept discontinuation, death, migration, or the end of the study period. Analyses were stratified by previous exposure to bDMARDs. Survival on drug was estimated using the Kaplan-Meier method. Predictors of discontinuation of abatacept were investigated in Cox Proportional Hazards analyses, with significance-based backwards stepwise selection of variables for the final multivariate model. Results: A total of 2716 patients with RA (80 % females, mean age 59 years, mean duration of RA 14 years) started abatacept during the study period. Of these, 17 % had no previous bDMARD treatment (bionaive patients), 27 % had received 1bDMARD previously, and 56 % had been treated with ≥2 bDMARDs. Fifty percent each of the patients received intravenous and subcutaneous therapy. At the time of abatacept initiation, 57 % were on methotrexate (MTX), and 48 % were treated with glucocorticosteroids. There were significant differences in drug survival across categories of previous bDMARD exposure (p=0.002). The median survival time on treatment was 2.23 years for bionaive patients (95 % confidence interval (CI) 1.69–2.79)), 1.68 years for those with 1 previous bDMARD (95 % CI 1.34–2.01) and 1.56 years for those with ≥2 previous bDMARDs (95 % CI 1.35–1.76). At 6 months, 88 % of bionaive patients remained on abatacept, compared to 74 % at 12 months. The corresponding figures for those with 1 or ≥2 previous bDMARDs were 78 % and 61 %, and 76 % and 59 %, respectively. In bivariate analyses, bionaive patients were less likely to discontinue treatment compared to those treated with ≥2 previous bDMARDs previously (Table). Bionaive patients were more often male (28 % vs 18 %) and had lower pain scores (mean Visual analogue scale score 58 vs 62) compared to those previously exposed to ≥2 bDMARDs. Measures of disease severity were associated with reduced drug survival (Table), but age, RA duration and method of administration had no significant impact on discontinuation. In the final multivariate model, pain increased the risk of abatacept discontinuation, whereas male patients and those on concurrent MTX had a reduced risk of stopping abatacept (Table). Conclusions: Survival on abatacept was significantly longer in bionaive RA patients compared to those previously exposed to bDMARDs. In the bionaive subset, 50 % of the patients remained on treatment after 2.2 years. Concomitant MTX therapy, male sex and low pain scores were associated with longer drug survival for abatacept. Disclosure of Interest: G. Cagnotto Paid instructor for: Novartis, M. Willim: None declared, J.-A. Nilsson: None declared, S. Saevarsdottir: None declared, C. Turesson Grant/research support from: Abbvie, Bristol Myers-Squibb, Roche. The present study was supported by an unrestricted grant from Bristol Myers-Squibb, Consultant for: MSD, Bristol Myers-Squibb, Roche, Paid instructor for: Abbvie, Bristol-Myers Squibb, Janssen, MSD, Pfizer, Roche and UCB