Treatment pattern and changes in oral glucocorticoid dose after tocilizumab treatment in patients with adult Still's disease: An analysis of a Japanese claims database

Aim: Intravenous tocilizumab (TCZ-IV) was approved for the treatment of adult Still's disease (ASD) in Japan in May 2019 based on its efficacy and safety in a phase III randomized controlled trial. This study determined treatment patterns in patients with ASD and assessed oral glucocorticoid (GC) dose changes after TCZ-IV administration in Japanese clinical practice. Methods: Patients in the Medical Data Vision database aged 16 years or older with one or more of International Classification of Diseases, 10th revision codes M061 (ASD) or M082 (systemic juvenile idiopathic arthritis) during January 2017–March 2021 (cohort 1) and those initiating TCZ-IV during May 2019–March 2021 (cohort 2) were included. Results: In cohort 1, the proportion of patients who were prescribed interleukin-6 inhibitors (mainly TCZ-IV) increased from 10.8% (January–April 2019 [before TCZ-IV approval]; n = 2002) to 18.3% (January–March 2021 [after TCZ-IV approval]; n = 2008). In cohort 2 (n = 193), 84.5% of patients were on oral GCs (≤5 mg/day: 23.8%) at index date (initial TCZ-IV prescription date); 46/70 (65.7%) were on oral GC at 5 mg/day or higher 12 months after TCZ-IV treatment (primary outcome). After 12 months of treatment, the TCZ-IV retention rate was 73.6% and the TCZ-IV administration interval was every 4 weeks and every 2 weeks in 31.9% and 27.7% of patients, respectively. Conclusion: The use of interleukin-6 inhibitors increased by 7.5% points in Japanese patients with ASD ~2 years after TCZ-IV approval, suggesting that an unmet medical need existed. This study suggests the potential GC-sparing effect of TCZ-IV in patients with ASD in clinical practice.