Evaluation of switching from intravenous to subcutaneous formulation of tocilizumab in patients with rheumatoid arthritis.

Objective: To evaluate the efficacy of switching the route from intravenous tocilizumab (TCZ) infusion (TCZ-IV) to subcutaneous TCZ injection (TCZ-SC) in a real-world setting through a comparison of the clinical response.
Methods: Fifty-eight rheumatoid arthritis (RA) patients, for whom TCZ-SC was initiated following TCZ-IV between June 2013 and August 2014, were consecutively enrolled. Disease activity score (DAS)28-ESR, simplified disease activity index (SDAI), and clinical disease activity index (CDAI) were examined at baseline and after switching from TCZ-IV to TCZ-SC for 3 months. We investigated whether body weight and body mass index (BMI) affected the efficacy of TCZ-SC.
Results: Most of the patients had achieved remission or low disease activity at baseline (77.6% examined by DAS28). Fifty-seven patients (98%) continued the TCZ-SC treatment, and the disease activity was well controlled after 3 months. ΔDAS28 tended to be worsened after switching to TCZ-SC in the high-body-weight groups (≥60 kg) as compared with the groups with body weight <60 kg, although no statistical significance was found. BMI did not affect the efficacy of TCZ-SC.
Conclusions: Caution should be exercised in the high-body-weight subjects, but these data indicate that TCZ-SC maintains the favorable RA disease activity established using TCZ-IV.