OBJECTIVES : Spinal muscular atrophies (SMA) are clinically and genetically heterogenous inherited orphan diseases leading to progressive spinal motoneurons degeneration and loss of function. Risdiplam and nusinersen are both authorized in Russia for pathogenic SMA treatment. The aim of the study was to perform health-economic evaluation of risdiplam in patients with SMA.

METHODS : The health-economic analysis was done in accordance with local Russian regulation. Due to absence of direct or indirect comparative effectiveness studies between risdiplam and nusinersen the cost-minimizing analysis was used. We accounted for direct medical costs of pathogenic treatment of SMA (risdiplam and nusinersen), adverse events correction and supportive care. Calculations of dosages and drugs direct medical costs were done based on the weight distribution of children and adolescent population in Russia. Decision tree analysis was used. In budget impact analysis the rise of risdiplam share from 0% to 8,5% was modelled at the time horizon – 3 years. The data from national SMA register was used to accurate calculation of the patient’s population size. Probabilistic sensitivity analysis was done changing the drug’s costs, size of patient’s population and the share of risdiplam and nusinersen.

RESULTS : Total direct medical costs for risdiplam (53 372 153 RUR for one patient in 3 years) were by 21,1% (14 968 427,82 RUR) lower comparing to nusinersen. The most pronounced difference in favor of risdiplam (41,9%) was during first treatment year. The rise of risdiplam share from 0% to 8,5% during 3 years is associated with lower budget costs by 13,9% in 3 years. Probabilistic sensitivity analysis confirmed the results of the main scenario.

CONCLUSIONS : Risdiplam is economically more effective comparing to nusinersen in Russian economic conditions, because having comparable effectiveness it’s use is associated with lower direct medical costs.