Trends in Prices, Market Share, and Spending on Self-administered Disease-Modifying Therapies for Multiple Sclerosis in Medicare Part D

Abstract

Importance: Before 2009, only 4 self-administered disease-modifying therapies (DMTs) were approved for the treatment of multiple sclerosis (MS). Since then, 7 new agents have entered the market.

Objective: To assess trends in prices, market share, and spending on self-administered DMTs for MS in Medicare Part D from 2006 through 2016.

Design, setting, and participants: This cohort study used claims data from 2006 through 2016 from a 5% random sample of Medicare beneficiaries (a mean of 2.8 million Medicare beneficiaries per year). All prescription claims for self-administered DMTs for MS (glatiramer acetate, interferon beta-1a, interferon beta-1b, fingolimod hydrochloride, teriflunomide, dimethyl fumarate, and peginterferon beta-1a) were extracted throughout the study period.

Main outcomes and measures: The main outcomes were the annual cost of treatment with each medication, based on Medicare Part D prescription claims gross costs and US Food and Drug Administration-approved recommended dosing; market share of each medication, defined as the proportion of pharmaceutical spending accounted by every drug; and pharmaceutical spending per 1000 Medicare beneficiaries for all drugs. The relative contributions of Medicare Part D Plans' payments, Medicare catastrophic coverage payments, low-income cost-sharing subsidies, patients' out-of-pocket costs, manufacturers' coverage gap discounts, and other payments toward pharmaceutical spending were further quantified.

Results: Annual costs of treatment with self-administered DMTs for MS more than quadrupled from 2006 to 2016, from a mean (SD) of $18 660 ($1177) to $75 847 ($16 956) and at a mean rate of 12.8% every year. Brand-name glatiramers accounted for the largest market share across the study period, ranging between $25 552 of $79 411 per 1000 Medicare beneficiaries (32.2%) and $10 342 of $21 365 per 1000 Medicare beneficiaries (48.4%). Platform therapies experienced a substantial drop from 2006 to 2016 in favor of newer therapies, with decreases in the market shares of brand-name glatiramers (per 1000 Medicare beneficiaries: $2861 of $7794 [36.7%] to $25 552 of $79 411 [32.2%]), interferon beta-1a (30 µg; per 1000 Medicare beneficiaries: $2521 of $7794 [32.3%] to $11 298 of $79 411 [14.2%]), interferon beta-1b (Betaseron; per 1000 Medicare beneficiaries: $1460 of $7794 [18.7%] to $3588 of $79 411 [4.5%]), and interferon beta-1a (8.8/22/44 µg; per 1000 Medicare beneficiaries: $951 of $7794 [12.2%] to $6588 of $79 411 [8.3%]) and increases in fingolimod (to $6311 of $79 411 per 1000 Medicare beneficiaries [7.9%]), teriflunomide (to $7177 of $79 411 per 1000 Medicare beneficiaries [9.0%]), and dimethyl fumarate (to $15 262 of $79 411 per 1000 Medicare beneficiaries [19.2%]). Throughout the study period, pharmaceutical spending per 1000 beneficiaries increased 10.2-fold (from $7794 to $79 411), and out-of-pocket patient spending per 1000 beneficiaries increased 7.2-fold (from $372 to $2673). The relative contribution of federal payments toward pharmaceutical spending increased from $5335 of $7794 (68.5%) to $58 620 to $79 411 (73.8%).

Conclusions and relevance: Per this analysis, prices of self-administered DMTs for MS increased dramatically between 2006 and 2016. This resulted in a 7.2-fold increase in patient out-of-pocket costs.

Figure 1.. Trends in Annual Cost of Treatment With Self-administered Disease-Modifying Therapies for Multiple Sclerosis in Medicare Part D, 2006-2016

The annual cost of treatment with each medication was calculated based on Medicare Part D prescription claims gross cost (before rebates) and US Food and Drug Administration–approved recommended dosages. For drugs marketed in multiple formulations, annual costs of treatment were calculated as the mean annual cost of treatment of their formulations, weighted by their relative market share every year. There are 2 different formulations of glatiramer: 20 mg (once daily) and 40 mg (3 times a week). Brand-name glatiramer in a 20-mg dose was approved in 1996, and the 40-mg branded formulation was approved in 2014. The first generic glatiramer in a 20-mg dose (Glatopa) was approved in 2015. Subsequently, a second generic of glatiramer at 20 mg and a new generic glatiramer at 40 mg were approved in 2017. Finally, a second generic of glatiramer at 40 mg was approved in 2018. Since this study period goes up to December 2016, this study only includes the first generic version of glatiramer in a 20-mg dose (Glatopa).

Figure 2.. Market Share of Self-administered Disease-Modifying Therapies for Multiple Sclerosis in Medicare Part D, 2006-2016

Market share was calculated as the proportion of pharmaceutical spending accounted by every drug each year.

Figure 3.. Trends in Spending and Relative Contribution of Stakeholders Toward Pharmaceutical Spending on Self-administered Disease-Modifying Therapies for Multiple Sclerosis in Medicare Part D, 2006-2016

A, Spending per 1000 Medicare beneficiaries for all self-administered, disease-modifying therapies approved for the treatment of multiple sclerosis. Spending per 1000 Medicare beneficiaries was defined as the absolute annual spending on self-administered disease-modifying therapies for multiple sclerosis in this sample, divided by the total number of beneficiaries in the sample each year, and multiplied it by 1000. B, The relative contribution (expressed as a percentage) toward pharmaceutical spending made by Medicare catastrophic coverage payments, Medicare Part D Plans payments, low-income cost-sharing subsidies, patients’ out-of-pocket payments, manufacturers’ coverage gap discounts, and other payments. The low-income cost-sharing subsidy provides assistance to certain low-income individuals to supplement patients’ cost-sharing (deductible and copayments) associated with the Part D benefit. Other payments include payments made by the Part D plan for benefits beyond the standard Part D benefit, payments made by third-party payers (eg, group health plans, worker's compensation, and governmental programs, such as the Veterans Administration and Tricare), and payments made by qualified state pharmacy assistance programs or charities. As an example, the Medicare Part D standard benefit design in 2016 was structured as (1) a deductible up to $360 (with beneficiaries bearing 100% of the spending); (2) an initial coverage period up to $3310 of spending (with beneficiaries bearing 25% and Medicare Part D plans 75% of the spending); (3) a coverage gap up to an out-of-pocket threshold of $4850 (with beneficiaries bearing 45%, Medicare Part D plans 5%, and manufacturers’ discounts 50% of the spending for brand-name drugs and beneficiaries bearing 58% and generic manufacturers’ discounts 42% of the spending for generic drugs); and (4) catastrophic coverage (with beneficiaries bearing 5%, Medicare Part D plans 15%, and Medicare 80% of the spending).