Use of Mycophenolate Mofetil for Systemic Sclerosis and Systemic Sclerosis-Associated Interstitial Lung Disease: Information from a Japanese Hospital Claims Database.

OBJECTIVES Limited information is available on patients with systemic sclerosis (SSc) or SSc-associated interstitial lung disease (SSc-ILD) receiving mycophenolate mofetil (MMF) in Japan. The dose, treatment duration, and patient characteristics of SSc and SSc-ILD patients receiving MMF were investigated. METHOD We used data from a Japanese hospital claims database (2008-2020). RESULTS Data on 486 SSc patients ≥18 years old receiving MMF were captured; 314 had SSc complicated with ILD. The most common initial daily doses were 1000 mg (SSc, 39.5%; SSc-ILD, 38.1%) and 500 mg (SSc, 36.6%; SSc-ILD, 34.6%). The most common maximum daily doses were 1000 mg (SSc, 33.3%; SSc-ILD, 34.9%), 1500 mg (SSc, 24.4%; SSc-ILD, 23.1%), and 2000 mg (SSc, 23.8%; SSc-ILD, 24.4%). Doses ranged from 250 to 3000 mg/day and were similar for SSc and SSc-ILD patients. Over 27% of patients received treatment for >1 year. There was a gradual decrease in steroid doses during MMF treatment. CONCLUSIONS Our study suggests that the off-label use of MMF for SSc and SSc-ILD has been increasing annually since 2015 in Japan. The doses used in patients with SSc and SSc-ILD were similar to the approved doses of MMF for lupus nephritis in Japan.