Disease modifying therapies continue to drive up health care cost among individuals with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a leading cause of disability in adults and requires lifelong treatment. Specialty drugs referred to as disease-modifying therapies (DMTs) have become the standard for multiple sclerosis treatment since the 1990s as they have been shown to reduce the risk of relapses and to delay disease progression. While more DMTs became available, prices of DMTs including existing drugs continue to rise and remain very expensive. This study is to estimate recent drug costs for DMTs and examine its impact on overall health care costs among individuals with MS enrolled in commercial insurance.

METHODS: This study is a population-based, retrospective study using 2011-2015 IBM MarketScan® Commercial Database. Individuals aged <65 years and with 12 months' continuous enrollment for both medical and pharmacy benefits in any of the measurement years were included. Patients were determined to have MS if they had at least three medical claims with a diagnosis for MS or one outpatient pharmacy claim for a DMT. Costs were computed using total amounts paid by insurance and patient; we report overall cost and cost by service category. All costs are reported using inflation-adjusted 2015 dollars.

RESULTS: The annual health care cost per MS patient increased from $45,471 in 2011 to $62,500 in 2015, an 8.3% average annual growth rate. The annual DMT cost per MS patient increased from $26,772 to $43,606, a 13.0% average annual growth rate. During this period, inpatient and other outpatient costs remained steady or decreased. When comparing DMT users to non-DMT users, the annual health care cost per DMT user was 74% higher in 2011 ($50,352 vs $28,881), increasing to more than twice higher in 2015 ($70,683 vs $29,821).

CONCLUSIONS: Annual health care costs for MS patients increased rapidly between 2011 and 2015, almost entirely due to the cost of DMTs. Older drugs as well as newly approved DMTs both drove this trend.