Patterns of tocilizumab use, effectiveness and safety in patients with rheumatoid arthritis: Core data results from a set of multinational observational studies

Objective To observe patients with rheumatoid arthritis (RA) treated with the interleukin-6 receptor-alpha inhibitor tocilizumab (TCZ) in routine clinical practice. Methods Data on concomitant medications, effectiveness and safety were pooled from independent, multinational studies in patients with RA initiating intravenous TCZ according to local label recommendations observed in routine practice for 6 months. Patients were grouped by TCZ monotherapy or combination therapy with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs). The primary endpoint was the proportion of patients receiving TCZ after 6 months. Results Of 1336 patients enrolled, 506 (37.9%) received TCZ monotherapy and 830 (62.1%) received combination therapy. Kaplan-Meier analysis estimated that 80% (95% CI, 76%-83%) of monotherapy and 87% (95% CI, 84%-89%) of combination therapy patients continued to receive TCZ at 6 months (log-rank p < 0.001). During the observation period, TCZ was discontinued by 113 (22.3%) monotherapy patients and 116 (14.0%) patients on combination therapy. The mean prednisone-equivalent oral corticosteroid dose was 8.4 mg/day for monotherapy and combination therapy patients at baseline and 7.7 and 7.6 mg/day, respectively, at month 6. Adverse events or laboratory abnormalities requiring TCZ dose modification were reported for 66 (13.0%) monotherapy and 130 (15.7%) combination therapy patients. Effectiveness at 6 months was similar between groups; mean (SD) change from baseline in Clinical Disease Activity Index (CDAI) was -20.3 (14.18) for monotherapy and -22.3 (16.09) for combination therapy (p=0.7347). Conclusion In routine clinical practice, 38% of patients received TCZ as monotherapy. Persistence on monotherapy or in combination therapy with csDMARDs was high, with a slight trend towards a higher rate with combination therapy, and effectiveness was similar between groups.