Estimating the Impact of the Inflation Reduction Act on the Out-of-Pocket Costs for Medicare Beneficiaries With Advanced Prostate Cancer.

Introduction: Combination systemic therapy for advanced prostate cancer has reduced mortality, but high out-of-pocket costs impose financial barriers for patients. The Inflation Reduction Act's $2,000 out-of-pocket spending cap for Medicare's prescription drug benefit (Part D) can potentially lower out-of-pocket spending for beneficiaries starting in 2025. This study aims to compare out-of-pocket spending for commonly prescribed regimens for advanced prostate cancer before and after implementation of the Inflation Reduction Act.

Methods: Medication regimens constructed to treat metastatic, hormone-sensitive prostate cancer consisted of baseline androgen deprivation therapy with traditional chemotherapy, androgen receptor inhibitors, and androgen biosynthesis inhibitors. Using 2023 Medicare Part B prices and the Medicare Part D plan finder, we estimated annual out-of-pocket costs under current law and under the Inflation Reduction Act's redesigned standard Part D benefit.

Results: Under current law, out-of-pocket costs for Part D drugs ranged from $464 to $11,336 per year. Under the Inflation Reduction Act, annual out-of-pocket costs for 2 regimens remained unchanged: androgen deprivation therapy with docetaxel and androgen deprivation therapy with abiraterone and prednisone. However, out-of-pocket costs for regimens using branded novel hormonal therapy were significantly lower under the 2025 law with potential savings estimated to be $9,336 (79.2%) for apalutamide, $9,036 (78.7%) for enzalutamide, and $8,480 (76.5%) for docetaxel and darolutamide.

Conclusions: The $2,000 spending cap introduced by the Inflation Reduction Act may significantly decrease out-of-pocket costs and reduce financial toxicity associated with advanced prostate cancer treatment, impacting an estimated 25,000 Medicare beneficiaries.