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.

Author Summary Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease treated with two antifibrotic medications: nintedanib and pirfenidone. These therapies are costly, and little is known about how Medicare has been spending on them in recent years. Using publicly available Medicare data from 2019 to 2023, we found that spending on nintedanib has increased significantly, while spending on pirfenidone has dropped. The average cost per prescription rose for both drugs. These findings may reflect changes in prescribing habits, patient access, and insurance coverage, and highlight the need to monitor drug costs and usage to ensure affordable treatment for patients.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study used publicly available, de-identified data from the CMS Medicare Part D Drug Spending Dashboard. As such, it did not involve human subjects and was exempt from IRB review.

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