Rheumatoid arthritis patients initiating rituximab with low number of previous bDMARDs failures may effectively reduce rituximab dose and experience fewer serious adverse events than patients on full dose: a 5-year cohort study

Abstract

Abstract Background Rituximab is used for the treatment of active rheumatoid arthritis. In the present study, we examined the long-term flare risk and safety of reduced doses of rituximab. Patients-methods This was a prospective, observational, single-center study of patients starting rituximab on standard dose (SD). Patients were switched to low dose (LD) (1 g every 6 months), based on the treating rheumatologist’s decision after having achieved sustained clinical responses, while the rest of the patients continued on standard dose (SD). During a 60-month period, we assessed (Kaplan–Meier survival analysis) the relapse rate (increase ≥ 1.2 in DAS28-ESR for ≥ 6 months) and discontinuations due to treatment failure in the low dose group, and we compared the incidence of serious adverse events (SAEs) between LD and SD groups. Results Out of 361 patients [females 83.4%, mean age 61.9 (10.6) years, seropositive 50.3%, median total comorbidities count 4], 81 patients (22.4%) entered LD in a median time of 24 months (95% CI 18–30 months). Seropositivity (OR 1.823), more than 2 previous bDMARDs failures (OR 0.428), and DAS28 < 4.88 at 6 months (OR 2.329) predicted the odds of entering LD (p < 0.05 for all). During 60 months of follow-up, only 7.5% of patients on LD relapsed. Patients on LD had significantly less SAEs and all-cause hospitalizations as compared to the SD group (p < 0.05 for all). Linear regression analysis showed that previous hospitalization while on bDMARDs (p < 0.0001), use of prednisolone > 5 mg/day while on rituximab (p < 0.0001), and a history of ≥ 2 previous csDMARDs (p = 0.041) predicted the risk of SAEs. Conclusion In a cohort of patients with established RA and significant comorbidities who taper rituximab after substantial initial disease activity improvement, a low rate of relapses and lower risk of SAEs compared to SD were recorded. Seropositivity, a lower number of previous bDMARDs use, and lower DAS28 at 6 months predicted the probability of entering the LD regimen.