Rheumatol Int 2018 Apr; 38(4):579-87In this observational study, the German RABBIT cohort was used to assess the long-term effectiveness and retention rates of tocilizumab (TCZ) in patients with prior bDMARD failures. Results of the study suggested that TCZ could be an effective treatment option for patients with difficult-to-treat RA. A total of 885 patients were involved in the study and these were categorised dependent on the number of bDMARD failures they had prior to TCZ treatment. Patient data recorded in the cohort included: prior bDMARD use, glucocorticoid use, comorbidities, DAS28-ESR and physical function data. Statistical analysis of the retention data revealed that retention was similar for patients who had been given ≤2 bDMARDs prior to TCZ therapy initiation. For patients treated with ≥3 bDMARDs retention was much lower, it was also noted that these patients had longer disease durations and tended to have three or more comorbidities. Disease activity recorded by DAS28-ESR scores revealed that all patients had significant improvement (P<0.05) during the follow-up months, irrespective of previous bDMARD exposure. Overall, the findings suggested that TCZ therapy was an effective treatment for RA patients as most patients achieved a low disease activity during the study, and treatment was equally effective across patient groups.