Abstract
BACKGROUND: Antifibrotics have been approved for use in many countries, including Japan, based on the results of several phase III clinical trials in patients with IPF, SSc-ILD, and PPF, which showed slower lung function decline with antifibrotic treatment. There is a paucity of information on the real-world use of antifibrotics in clinical practice. METHODS: Baseline characteristics, comorbidities, and drugs used prior to and concomitant with antifibrotics were collected for patients with IPF, SSc-ILD, and PPF using a health insurance claims database in Japan from 1 January 2013 to 30 June 2023. Descriptive statistics were generated for all study variables. RESULTS: This study included 657 nintedanib users with IPF; 418 pirfenidone users with IPF; 4160 nintedanib users with PPF; 18,403 users of glucocorticoids/immunosuppressants for ILD treatment with PPF; 676 nintedanib users with SSc-ILD; and 698 users of glucocorticoids/immunosuppressants for ILD treatment with SSc-ILD. At index, pirfenidone users with IPF were the oldest (mean [SD] 74.8 [7.3] years), and nintedanib users with SSc-ILD were the youngest (mean [SD] 65.6 [11.7] years). In nintedanib users with IPF, 76.7% were prescribed nintedanib as monotherapy, and 75.6% of pirfenidone users were prescribed pirfenidone, as monotherapy. In patients with IPF, 75.2% were prescribed nintedanib, and 76.1% were prescribed pirfenidone, as first-line therapy. In patients with SSc-ILD, 34.9% were prescribed nintedanib as monotherapy for ILD treatment, and 38.6% as first-line therapy. Approximately half of patients with PPF were prescribed nintedanib concomitantly with other glucocorticoids/immunosuppressant drugs, and after one or more glucocorticoids/immunosuppressant drugs. The most common concomitant drug in all patient groups was glucocorticoids. In patients with IPF, 18.6% of nintedanib users and 18.2% of pirfenidone users were prescribed glucocorticoids concomitantly. Concomitant glucocorticoid use was 52.7% for nintedanib users with SSc-ILD, and 44.1% for nintedanib users with PPF. CONCLUSIONS: These results provide real-world evidence of antifibrotic use in clinical practice. Most patients with IPF were prescribed antifibrotics as monotherapy for ILD treatment whereas antifibrotics were used concomitantly with glucocorticoids/immunosuppressants in many patients with SSc-ILD and PPF. While most patients with IPF were prescribed antifibrotics as first-line therapy, patients with SSc-ILD and PPF were more likely to be prescribed nintedanib as second-line or later-line treatment after glucocorticoids/immunosuppressants.