AB0444 Description in real-world of the efficacy after switching from intravenous to subcutaneous administration of tocilizumab in patients with rheumatoid arthritis. the roswitch study

BackgroundIt has been proven, in a pivotal RCT, that SC tocilizumab (TCZ) was non-inferior to IV TCZ.1 However the switch from IV to SC TCZ has not been evaluated to date in a large real-world study.ObjectivesThe main objective was to assess the maintenance of efficacy of SC TCZ 6 months (M6) after switching from IV to SC formulation in patients (pts) with rheumatoid arthritis (RA) in real-world. Secondary objectives were: characteristics of pts and RA, efficacy of TCZ at M12, TCZ retention rates at M6 and M12 for Switch (IV-SC) and No-Switch pts (IV-IV), predictive factors of switching.MethodsWe analysed all RA pts of the shared medical file “RIC Nord de France” with ≥1 DAS 3 months before inclusion, treated with TCZ, switching or not from IV to SC TCZ, between April 30 2015 and January 15 2016. The primary efficacy endpoint was the% of pts remaining in their DAS28-ESR category remission/LDA or moving to an inferior DAS category at M6. Various sensibility analyses were realised on the primary criterion of which a propensity score (IPTW).ResultsFrom the 314 included pts, 30% switched from IV to SC TCZ. At baseline, 77.7% were females, mean BMI was 27.5±6.4, mean RA duration was 14.9±9.2 years. Mean IV TCZ duration before inclusion was 35.0±23.1 months in Switch and 26.8±22.1 months in No-Switch pts. Mean DAS28 were 2.1±1.1 in Switch and 2.9±1.6 in No-Switch pts. 81.9% and 59.5% of the pts were in DAS28 remission/LDA, 18.1% and 28.6% in MDA, 0% and 11.8% in HAD in Switch and No-Switch pts respectively. The improvement of initial DAS28-ESR category or maintenance in remission/LDA was comparable in both groups at M6 and M12 (table 1). Using the IPTW for balancing on baseline characteristics between groups, similar proportions were observed at both M6 and M12. TCZ retention rates at M12 were 78% (95% CI68–85 and 80% (95% CI: 74–85 p=0.555 for Switch and No-Switch groups respectively. In the 208 pts with a DAS28 ≤3.2 at inclusion, multivariate analysis showed no parameters associated to the switch. Conversely in the 106 pts with a DAS28 >3.2 at inclusion, rheumatoid nodules (OR=4.78, 95% CI [1.23–18.55], p=0.024) and duration of IV TCZ before inclusion (OR=1.37, 95% CI [1.08–1.73], p=0.009) were significantly associated to the switch.ConclusionsThe RoSwitch study showed the maintenance of efficacy at 6 and 12 months in RA pts switching from IV to SC TCZ. Similar efficacy and therapeutic retention rates were observed for No-Switch pts. No factor was associated with the switch in pts in remission/LDA at inclusion suggesting that patient’s personal appreciation was preponderant in the choice of the switch.References[1] Burmester GR, et al. Ann Rheum Dis2014Jan;73(1):69–74.Disclosure of InterestJ. Darloy: None declared, N. Segaud: None declared, J.-H. Salmon: None declared, V. Goeb: None declared, M.-H. Guyot: None declared, L. Marguerie: None declared, C. Chopin: None declared, S. Gally Employee of: Roche SAS, I. Idier Employee of: Chugai Pharma France, G. Baudens: None declared, R.-M. Flipo Consultant for: Roche. Chugai Pharma France