A new study published in Pharmaceutical Medicine has revealed staggering growth in the utilization and cost of novel therapies for Duchenne muscular dystrophy (DMD) within the U.S. Medicaid program, raising urgent questions about affordability and equitable access.
From 2017 and 2022, prescriptions for four FDA-approved exon-skipping therapies — eteplirsen (Exondys 51), golodirsen (Vyondys 53), viltolarsen (Viltepso) and casimersen (Amondys 45) — rose nearly 3,000%, the researchers reported. During the same period, Medicaid spending on these drugs grew by 2,809%, climbing from $22 million in 2017 to more than $640 million in 2022.
Exon-skipping therapies for DMD are designed to slow disease progression, but each one applies only to a subset of patients. Mutations can occur in many different locations on the DMD gene, and patients must have a genetic mutation amenable to the drug.
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Eteplirsen, approved in 2016, was the only targeted therapy available in 2017 (when the study period began) and had 643 prescriptions that year. By 2022, the Medicaid program covered nearly 20,000 prescriptions across all four exon-skipping drugs. Eteplirsen remained the most prescribed therapy, with over 13,000 prescriptions that year, while the newer drugs saw rapid uptake. Casimersen, for instance, grew from 716 prescriptions in 2021 to nearly 3,900 in 2022.
While total costs skyrocketed, the average cost per prescription fell about 6%, from $34,258 in 2017 to $32,279 in 2022. Still, individual therapies remain extremely expensive, with estimates suggesting annual costs range from roughly $300,000 for a small child to nearly $1 million for an older child or adolescent.
The authors point to multiple factors contributing to the steep increase in spending, including the approval of additional drugs that expanded eligibility, the expansion of Medicaid enrollment under the Affordable Care Act and improved survival leading to long-term treatment needs.
The findings highlight a major challenge for Medicaid, which covers many children with rare diseases. By 2022, its reimbursement for DMD therapies exceeded $640 million annually. This number is expected to grow as more new drugs, including gene therapies, enter the market.
The study’s authors said that while these treatments represent scientific breakthroughs, their rapid uptake highlights the need for new cost-containment measures. Without careful policy planning, they noted, the escalating financial burden may threaten the sustainability of Medicaid programs and risk inequitable access for families who depend on them.
“The considerable rise in the utilization and spending of novel DMD drugs has imposed a significant burden on the Medicaid budget, underlining the need for policy measures to manage rising costs and maintain equal access to treatment,” the researchers concluded.
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