THU0174 ANTI-IL-6 RECEPTOR ANTIBODY AMELIORATES DISEASE ACTIVITY OF RHEUMATOID ARTHRITIS PATIENTS WITH KNEE JOINT INVOLVEMENT -ANSWER COHORT STUDY-

Background: Biosimilar etanercept (ETA-B) was recently introduced in Canada but real-world data descriptions of drug persistence (and comparisons with the originator product, ETA-O) are still scarce. Objectives: To describe and compare persistence of ETA-B and ETA-O in RA. Methods: We used data from four ongoing, prospective cohorts in Canada: the Canadian Early Arthritis Cohort (CATCH), the Rheumatoid Arthritis Pharmacovigilance Program and Outcomes Research in Therapeutics (RAPPORT), the Early Undifferentiated Polyarthritis (EUPA) cohort, and the RHUMADATA® registry. We studied biologic-naive and biologic-experienced RA adults initiating ETA-B or ETA-O between Jan. 2015 and Oct. 2019. Switchers from ETA-O to ETA-B (or vice-versa) were included. We assessed persistence of therapy in the first 12 or 24 months, measured as time from therapy initiation (time zero) to discontinuation. Individuals switching between products could contribute further person-time to the new exposure category. Multivariable Cox regression models were performed with each cohort dataset separately, following a common protocol. Model variables included age, sex, comorbidity, past biologic use, and disease duration. After testing for between-study heterogeneity (Higgin’s I2), cohort-estimated hazard ratios (HR) were pooled using random effects meta-analysis. Results: We identified 262 episodes of etanercept use (118 ETA-B and 144 ETA-O) from 250 RA patients. Sex, age, and other baseline characteristics across the four cohorts are shown in Table 1. Across cohorts, there was considerable variation in RA duration at the time of initiating ETA-B or ETA-O. In the pooled analysis, the HR for discontinuation at 24 months comparing ETA-B to ETA-O was 0.51 (95% confidence interval, CI: 0.26-0.98). The pooled analysis for therapy discontinuation at 12 months adjusted HR in this analysis was 0.82 (95% CI: 0.42-1.60). Conclusion: Despite wide confidence intervals, the 24-month data suggested potential better persistence with ETA-B versus ETA-O, with a similar trend at 12 months. Some of the observed associations may be related to residual confounding (e.g. disease activity, time-dependent effects of concomitant medications) and/or survivorship bias (in patients transitioning from ETA-O to ETA-B). Disclosure of Interests: Cristiano S Moura: None declared, Denis Choquette Grant/research support from: Rhumadata is supported by grants from Pfizer, Amgen, Abbvie, Gylead, BMS, Novartis, Sandoz, eli Lilly,, Consultant of: Pfizer, Amgen, Abbvie, Gylead, BMS, Novartis, Sandoz, eli Lilly,, Speakers bureau: Pfizer, Amgen, Abbvie, Gylead, BMS, Novartis, Sandoz, eli Lilly,, Louis Coupal: None declared, Orit Schieir: None declared, Marie-France Valois: None declared, Vivian Bykerk: None declared, Gilles Boire Grant/research support from: Merck Canada (Registry of biologices, Improvement of comorbidity surveillance) Amgen Canada (CATCH, clinical nurse) Abbvie (CATCH, clinical nurse) Pfizer (CATCH, Registry of biologics, Clinical nurse) Hoffman-LaRoche (CATCH) UCB Canada (CATCH, Clinical nurse) BMS (CATCH, Clinical nurse, Observational Study Protocol IM101664. SEROPOSITIVITY IN A LARGE CANADIAN OBSERVATIONAL COHORT) Janssen (CATCH) Celgene (Clinical nurse) Eli Lilly (Registry of biologics, Clinical nurse), Consultant of: Eli Lilly, Janssen, Novartis, Pfizer, Speakers bureau: Merck, BMS, Pfizer, Walter P Maksymowych Grant/research support from: Received research and/or educational grants from Abbvie, Novartis, Pfizer, UCB, Consultant of: WPM is Chief Medical Officer of CARE Arthritis Limited, has received consultant/participated in advisory boards for Abbvie, Boehringer, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, Novartis, Pfizer, UCB, Speakers bureau: Received speaker fees from Abbvie, Janssen, Novartis, Pfizer, UCB., Sasha Bernatsky: None declared