Reducing the Out-of-Pocket Costs of Disease-Modifying Therapies for Medicare Beneficiaries With Multiple Sclerosis

The Inflation Reduction Act (IRA) introduced major reforms to Medicare Part D, including an annual out-of-pocket (OOP) maximum and the Medicare Prescription Payment Plan (MPPP), which allows beneficiaries to spread OOP costs over monthly payments. The IRA's Part D provisions, as well as wider use of direct-to-consumer (DTC) pharmacies, could reduce OOP costs for self-administered disease-modifying therapies (DMTs) among Medicare beneficiaries with multiple sclerosis (MS). This study estimated OOP costs for self-administered DMTs under the IRA's Part D provisions and through DTC pharmacies.

We calculated OOP costs for brand-name and generic DMTs under Part D in the pre-IRA (2023) and post-IRA (2025) periods. We also assessed the impact of voluntary enrollment in the MPPP in 2025. Finally, we examined OOP costs for generic DMTs purchased through DTC pharmacies.

Before the IRA (2023), annual OOP costs ranged from $6,275 to $8,883 for brand-name DMTs; after the IRA (2025), annual OOP costs decreased by 68%-77% because all brand-name DMT users reached the annual OOP maximum ($2,000 in 2025). OOP costs were heavily frontloaded as lumpsum payments unless beneficiaries enrolled in the MPPP, which could lead to monthly payments as low as $167 for DMTs in 2025 (a reduction of over 90% in monthly OOP costs for January). Generic DMTs had annual OOP costs ranging from $212 to $7,855 before the IRA (2023) and $212 to $2,000 after the IRA (2025). Purchasing generic DMTs through DTC pharmacies resulted in annual OOP costs ranging from $133 to $39,984 and could lead to lower costs for some beneficiaries.

Annual OOP costs for self-administered DMTs among Medicare beneficiaries with MS decreased significantly beginning January 1, 2025, because of the IRA's annual OOP maximum. Beneficiaries who voluntarily enroll in the MPPP will also be able to spread OOP costs over more manageable monthly payments. Direct cash purchase of some generic DMTs through DTC pharmacies could lead to lower OOP costs, but these payments will not count toward beneficiaries' deductible or annual OOP maximum. Neurologists have a critical role in ensuring that their Medicare patients with MS are aware of the option to enroll in the MPPP and the possibility of obtaining generic DMTs through DTC pharmacies.