Abstract
Background: The availability of high-efficacy disease-modifying therapy (DMT), including natalizumab, improved treatment efficacy in adults with highly-active relapsing-remitting multiple sclerosis (RRMS). Natalizumab patent protection has expired, and the natalizumab biosimilar (Tyruko®) has been recently reimbursed by AIFA. As the price of natalizumab biosimilar is expected to be lower as compared with natalizumab originator’s price, a budget impact analysis was conducted to assess the economic impact associated to the introduction of natalizumab biosimilar for patients with highly-active RRMS.
Methods: A budget impact model was developed, considering the INHS perspective and a 5-years time horizon. The number of patients treated with natalizumab was estimated based on historical natalizumab consumption data, disease prevalence rates and natalizumab market share. The budget impact population was divided into prevalent and incident patients. The model assumes that some patients in treatment with natalizumab originator will switch to natalizumab biosimilar and that some naïve patients will directly start treatment with natalizumab biosimilar. The ex-factory price of natalizumab originator (intravenous and subcutaneous) and biosimilar (intravenous) and the corresponding administration costs were included. All assumptions were validated by expert opinion.
Results: Eligible population was estimated at 7,552, 7,779, 8,090, 8,494 and 8,834 in years 1, 2, 3, 4 and 5 respectively. The introduction of natalizumab biosimilar, considering a progressive increase in market share from 9.6% (year 1) to 40.5% (year 5), would provide an overall savings (5-years time horizon) over € 47 million to the INHS. The scenario analysis highlights that the lower treatment cost of biosimilar natalizumab compared to originator natalizumab would offset the higher cost associated with intravenous versus subcutaneous administration.
Conclusion: Considering the results of this budget impact analysis, it is realistic to expect that the presence of biosimilar natalizumab will contribute to the sustainability of public pharmaceutical expenditure.