Safety and efficacy profiles of tocilizumab monotherapy in Japanese patients with rheumatoid arthritis: meta-analysis of six initial trials and five long-term extensions.

We present safety and efficacy data from Japanese clinical studies on monotherapy with tocilizumab (TCZ), a humanized anti-interleukin 6 receptor monoclonal antibody, in which 601 patients with moderate to severe rheumatoid arthritis, with a total of 2188 patient-years (pt-yr) exposure, were enrolled. The median treatment duration was 3.8 years. The incidence of adverse events (AEs), including abnormal laboratory test results, was calculated as 465.1 per 100 pt-yr. The most common serious adverse events (SAEs) were infections (6.22 per 100 pt-yr). There was no increase in the frequency of AEs or SAEs with long-term treatment. Abnormalities in the laboratory test results, such as increases in lipid parameters or abnormal liver function parameters, were common, but most were mild and there were no SAEs related to them. At baseline, 546 patients (90.8%) were taking corticosteroids; of these, 77.8% were able to decrease their corticosteroid dose during the study period, while 35.2% discontinued corticosteroids altogether. In the patients treated longer than 5 years, 91.3, 73.0, and 51.3% met the ACR20, ACR50, and ACR70 response criteria, respectively, and 59.7% met the DAS remission criterion (DAS28 <2.6) at 5 years. In conclusion, based on these results, TCZ has shown good tolerability and high efficacy during long-term treatment.