OBJECTIVES: In 2022, the US government announced the Inflation Reduction Act (IRA), which included several provisions to lower prescription drug costs for Medicare patients and reduce federal government spending. In 2025, the legislation will introduce a $2,000 hard cap on out-of-pocket spending, while mandating commercial plans to cover 60% of costs from catastrophic coverage. In 2023, nine biosimilar of adalimumab launched in the US. Most products were launched with list prices that are slightly lower, and among them, five have launched with significantly discounted versions (low-WAC, with discount rates between 55% and 86%). In this study, our aim is to compare the cost of high-WAC and low-WAC adalimumab biosimilars for the Medicare program by estimating the amount that each stakeholder would spend in 2025.

METHODS: Costs levied on each stakeholder: the government, commercial plans, manufacturers, and beneficiaries were compared under the Medicare Part D standard eligibility group scheme. We assumed the annual cost of treatment would be about 85,000 USD for high-WAC products and 17,000 for low-WAC products.

RESULTS: The results showed that in 2025, patient out-of-pocket spending for low-WAC and high-WAC products would be the same. For commercial plans, contributions would be 51,000 and 10,000 USD for high-WAC products and low-WAC products, respectively. The commercial plan’s financial burden accounts for 59.7% of the annual cost of treatment with adalimumab. For manufacturers, contributions would be 16,000 and 3,000 USD for high-WAC products and low-WAC products, respectively. Lastly, Medicare contributions would be 16,000 and 2,000 USD, for high-WAC products and low-WAC products, respectively.

CONCLUSIONS: Comparing each stakeholder’s contribution in Medicare program in 2025, the financial burden for Medicare, commercial plans and manufacturers is significantly reduced in low-WAC products compared to that of high-WAC products.