Coverage for high-cost specialty drugs for rheumatoid arthritis in Medicare Part D

More than 1 in 4 Medicare beneficiaries with rheumatoid arthritis use high-cost biologic disease-modifying antirheumatic drugs (DMARDs), and spending for these drugs has risen sharply for Medicare Part D. Our aim was to conduct the first systematic, national investigation of how Part D plans cover biologic DMARDs and to determine patients' financial burden under current cost-sharing structures.

We performed a cross-sectional analysis of Part D plan formularies (n = 2,737) in 50 states and Washington, DC using the January 2013 Centers for Medicare and Medicaid Services Prescription Drug Plan Formulary and Pharmacy Network Files. We calculated the percentage of plans covering each DMARD as well as the percentage requiring prior authorization and/or coinsurance. We also compared biologic drug coverage in Medicare Advantage prescription drug plans to that in Medicare Part D stand-alone plans.

All plans covered at least 1 biologic DMARD, but the vast majority required prior authorizations (95%). Nearly all plans (81-100%) required patients to pay a coinsurance percentage (averaging 29.6% of drug costs) rather than a fixed dollar copayment. This translated into mean out-of-pocket costs of $2,712-$2,774 before reaching the catastrophic phase of coverage, during which beneficiaries pay 5% of drug costs. Medicare Advantage prescription drug plans covered more individual biologic DMARDs (55-100%) than did Medicare Part D stand-alone plans (22-100%), but Medicare Advantage prescription drug plans required higher average coinsurance (31.1% versus 29.0%). In contrast, 6 of 9 nonbiologic DMARDs were covered by nearly all plans without prior authorizations at fixed copayments averaging $5-$10/month.

Nationally, nearly all Part D plans cover at least 1 biologic DMARD, but the vast majority require cost sharing sufficiently high to risk significant financial burden to patients.