Treat-to-target vs fixed interval retreatment strategy with rituximab in rheumatoid arthritis: a retrospective cohort study.

To compare the effectiveness of retreatment of rheumatoid arthritis (RA) patients with rituximab (RTX) following the treat-to-target retreatment (TTr) or fixed interval retreatment (FIr) strategy. RA patients starting RTX treatment between January 2008 and June 2016, and receiving at least three infusion cycles were grouped by strategy (TTr, FIr or both). Primary outcome (between strategy difference in DAS28-CRP (Disease Activity Score in 28 joints calculated with C-reactive protein)) and secondary outcomes (flares, use of co-medication and mean yearly dose of RTX) were analyzed by group using linear mixed models to account for different strategies within patients. A total of 213 patients, 59 TTr (of whom 32 switched from TTr to FIr) and 186 FIr were included. No between-group difference in mean DAS28-CRP was found (0.10 DAS28-CRP point (95% CI - 0.07 to 0.26)). The TTr strategy did not result in more flares (IRR 1.13, 95%CI 0.87 to 1.47), conventional synthetic disease-modifying antirheumatic drug use (difference - 11.7%, 95%CI - 26.3% to 2.9%), or lower mean yearly RTX dose (difference 172 mg/yr, 95%CI - 355 to 11.7 mg/yr). RTX retreatment with either a TTr or FIr strategy does not seem to lead to better disease control and/or less drug use when used in a DAS28-CRP treat-to-target context. Choice of either strategy can, therefore, be made based on patient and physician preferences and logistical context.