Comparing Effectiveness Rituximab (Mabthera^®) to Other Second-line Biologics for Rheumatoid Arthritis Treatment in Patients Refractory to or Intolerant of First-line Anti-tumor Necrosis Factor Agent: An Observational Study

Objective. Failure of first-line anti-tumor necrosis factor (TNF) agents in in rheumatoid arthritis patients leads to decisions among second-line biologic agents. To better inform these decisions, the therapeutic effectiveness of rituximab is compared with other second-line biologic agents in this observational study. Methods. Between November 2011 and December 2014, study subjects were observed for 12 month periods. Patients with an inadequate response to initial anti-TNF agent received either rituximab or alternative anti-TNF agents (adalimumab/etanercept/infliximab) based on the preference of patients and physicians. The efficacy end point of this study was the change in 28-joint count Disease Activity Score (DAS28) at six and 12 months from baseline. Safety data were also collected. Results. Ninety patients were enrolled in the study. DAS28 at six months did not change significantly whether the patients were treated with rituximab or alternative anti-TNF agents in intention-to-treat analysis (n=34, $-1.63{\pm}0.30$ vs. n=31, $-2.05{\pm}0.34$) and standard population set analysis (n=31, $-1.51{\pm}0.29$ vs. n=24, $-2.21{\pm}0.34$). Similarly, the change in DAS28 at 12 months did not reach statistical significance ($-1.82{\pm}0.35$ in the rituximab vs. $-2.34{\pm}0.44$ in the alternative anti-TNF agents, p=0.2390). Furthermore, the incidences of adverse events were similar between two groups (23.5% for rituximab group vs. 25.8% for alternative anti-TNF agents group, p=0.7851). Conclusion. Despite the limitations of our study, switching to rituximab or alternative anti-TNF agents after failure of the initial TNF antagonist showed no significant therapeutic difference in DAS28 reduction.