Trends in Medicare Part D Spending on Antifibrotic Therapies for Pulmonary Fibrosis: 2019–2023

Background: Nintedanib and pirfenidone are antifibrotic agents approved for the treatment of idiopathic pulmonary fibrosis (IPF) and progressive fibrosing interstitial lung diseases. Despite their clinical significance, national trends in Medicare Part D spending and utilization for these therapies remain insufficiently characterized. Objective: To evaluate national trends in Medicare Part D spending, claims, and cost-per-claim for nintedanib and pirfenidone from 2019 to 2023. Methods: Medicare Part D Drug Spending Dashboard data were analyzed for total spending, number of claims, and average spending per claim for nintedanib and pirfenidone. Trends over five years were assessed. Results: Total spending on nintedanib increased from 2019 to 2023, with a consistent rise in both claims and average cost per claim. In contrast, pirfenidone’s total spending declined sharply, primarily due to a reduction in claims. The average cost per claim for both drugs increased over the study period. Conclusion: Medicare spending on antifibrotic therapies is increasingly dominated by nintedanib, reflecting evolving prescribing patterns and potential differences in tolerability or access. These findings have implications for cost-containment strategies and formulary management.