Broader Formulary Coverage Linked to Lower Odds of MS Relapse

FRIDAY, Aug. 8, 2025 (HealthDay News) — Broader formulary coverage is associated with lower odds of multiple sclerosis (MS) relapse among Medicare beneficiaries, according to a study published online Aug. 1 in JAMA Network Open.

Barbara Blaylock, Ph.D., from Blaylock Health Economics LLC in Reno, Nevada, and colleagues examined the association between the breadth of formulary coverage for MS disease-modifying therapies and MS relapse in a retrospective cohort study that analyzed 100 percent Medicare administrative data from 2018 to 2022. Beneficiaries with stand-alone prescription drug plans (PDPs) and Medicare Advantage Prescription Drug plans (MA-PDs) were followed for at least five quarters (baseline: quarters 1 to 4; follow-up: quarter 5).

A total of 50,162 unique beneficiaries in PDPs and 34,708 in MA-PDs were included in the claims analysis. The researchers found that the MS relapse rate was greater for low- versus high-coverage PDPs and MA-PDs (odds ratios, 0.88 and 0.88). There was an association for broader formulary coverage during baseline with less MS relapse during follow-up in multivariable analyses (adjusted odds ratios, 0.93 and 0.94 for drugs and classes for PDP; 0.88 and 0.92 for drugs and classes for MA-PD, respectively).

“Patients with MS may need to try multiple drugs to find what works best for them. Broad formulary exclusions ultimately undermine the individualized care these patients need,” lead author Geoffrey Joyce, Ph.D., from the University of Southern California, Los Angeles, said in a statement.

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