Budget impact analysis of biosimilar natalizumab in the US.

ABSTRACT

OBJECTIVES: Biosimilars provide an opportunity for a more sustainable and cost-effective treatment for multiple sclerosis (MS). This study evaluated the potential financial impact of implementing a formulary change from reference to biosimilar natalizumab (NTZ) from the US commercial payer perspective. STUDY DESIGN: The budget impact of transitioning to biosimilar NTZ for the treatment of relapsing-remitting MS (RRMS) was estimated over a 3-year time horizon based on real-world dosing. Additional scenario analyses were conducted by varying the price differential of biosimilar NTZ. METHODS: The target population was estimated from a 1-million-member hypothetical commercial health plan. Model inputs were drug acquisition costs and treatment-related and patient coinsurance costs. Budget impact and cost savings per member per year were calculated by assuming a biosimilar uptake of 10% in year 1 to 20% in year 3. RESULTS: Over 3 years, 255 patients were estimated to be treated with high-efficacy disease-modifying therapies for RRMS. The inclusion of biosimilar NTZ onto a formulary would result in cumulative cost savings to payers of $452,611 over 3 years, with mean savings per treated member per year of $1179, $1769, and $2359 in years 1, 2, and 3, respectively. One-way sensitivity analyses indicated that budget impact results were most sensitive to drug acquisition costs of both reference and biosimilar NTZ. CONCLUSION: Adoption of biosimilar NTZ can yield considerable cost savings to US health plans that could result in increased treatment access for patients with RRMS.