AB0371 LONG TERM RITUXIMAB PERSISTENCE FOR RHEUMATOID ARTHRITIS IN THE REAL WORLD: THE RITAR STUDY
Authors: Iciar Cañamares Orbis, Leticia Merino-Meléndez, Irene Llorente, Juana Benedi Gonzalez, Rosario Garcia de Vicuna, Alberto Morell, Isidoro González-álvaro, Esther Ramirez
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Rituximab (RTX) is a B-lymphocyte depleting monoclonal antibody that was approved for rheumatoid arthritis (RA) treatment in Europe in 2006. <h3>Objectives</h3> To analyse factors affecting long term persistence of RTX for the treatment of RA patients in daily clinical practice. <h3>Methods</h3> RITAR (RITuximab en Artritis Reumatoide) is a retrospective, open-label, observational study that describes the patterns of use and long term persistence of RTX in a tertiary university hospital from 2003 to 2015. We collected demographic, clinical and therapeutic variables. Patients who discontinued RTX were considered events whereas patients lost for follow-up and non-RTX-related deaths were censored. Statistical analysis was performed with STATA 12. Kaplan-Meier survival analysis, Log-rank test and Cox Regression were used. A multivariable Cox-proportional hazards model was fitted to determine which variables were most likely related to RTX persistence. <h3>Results</h3> 114 patients were included: 80.7% women, median age 60 years (IQR 51-69) and median RA duration 11 years (IQR 6-16). Most patients were FR/ACPA positive (93.0%). Retreatment schedule was 94.6% on demand and 5.4% fixed-retreatment every 6 months. In the 1<sup>st</sup> cycle RTX monotherapy used in 12.2% and gradually increased over time. The mean RTX dose by cycle was 1,733 mg (DE: 294): 324 x 2000 mg and 130 x 1000 mg. RTX was used as 1<sup>st</sup> biologic in 19.3%. Median response duration was 10 months (IQR 7-13). We observed 38 events, 22 patients were censored and 54 remained on RTX treatment at the end of the study. Follow-up time in analysis was 484.84 years. Median survival was 9.98 years, withdrawal rate was 7.67/100 patients-year. Reasons for discontinuation were 21.0% ineffectiveness, 8.7% adverse events and 3.5% deaths probably related with RTX. Log-Rank test: p=0.013 Log-Rank test: p=0.014 Log-Rank test: p=0,066 <h3>Conclusion</h3> In our hospital RTX treatment has a long median survival that is significantly higher in seropositive patients and in those treated in combination with csDMARDS. The RTX dose by cycle did not affect the persistence. <h3>Reference</h3> [1] Cañamares-Orbis I, Merino L, Lopez J, Llorente I, Garcia-Vadillo A, Ramirez E, et al. Experience With the Use of Rituximab for the Treatment of Rheumatoid Arthritis in a Tertiary Hospital in Spain: RITAR Study. J Clin Rheumatol. 2018. <h3>Disclosure of Interests</h3> Iciar Cañamares Orbis: None declared, Leticia Merino-Meléndez: None declared, Irene Llorente : None declared, Juana Benedi Gonzalez: None declared, Rosario Garcia de Vicuna Grant/research support from: Abbvie, BMS, Lilly, MSD, Novartis, Roche, Consultant for: Biogen, BMS, Mylan, Pfizer, Sanofi and Sandoz, Speakers bureau: BMS, Pfizer, Lilly, Sandoz, Alberto Morell Grant/research support from: Abbvie, Amgen, Biogen, BMS, Celgene, Grifols, MSD, Novartis, Roche, Consultant for: Abbvie, Amgen, Biogen, BMS, Celgene, Grifols, Kern, Lilly, MSD, Novartis, Roche, Paid instructor for: Abbvie, Amgen, Biogen, BMS, Celgene, Grifols, Kern, Lilly, MSD, Novartis, Roche, Speakers bureau: Abbvie, Amgen, Biogen, BMS, Celgene, Grifols, Kern, Lilly, MSD, Novartis, Roche, Sandoz, Isidoro González-álvaro: None declared, Esther Ramirez: None declared