OBJECTIVES: The aim of this analysis was to assess the cost-effectiveness of risdiplam in comparison to available disease modifying treatments (DMTs) for patients with Type 1-3 SMA as demonstrated to the French National Authority for Health (HAS).

METHODS: Two six-state semi-Markov models were adapted to the French collective perspective to evaluate the incremental cost-effectiveness ratio (ICER) of risdiplam. Costs and outcomes were discounted at 2.5% with direct medical costs derived from a French database (SNDS). The Type 1 SMA model health states (‘not sitting’,‘sitting’, ‘standing’, ‘walking’, ‘permanent ventilation’ and death’) were modelled over a 10-year time horizon using efficacy results from the FIREFISH trial. Comparative effectiveness nusinersen and best supportive care (BSC) were based on an indirect treatment comparison (ITC), while equivalent efficacy was assumed for onasemnogene abeparovec (OA). Life years gained (LYG) were assessed within the ICER due to the difficulty to collect utilities for infants. Type 2-3 SMA was modelled over 40 years with transition probabilities and utilities (EQ-5D) were based on data from SUNFISH trial (risdiplam, BSC (placebo)). Comparative effectiveness of nusinersen was based on an ITC. Uncertainty analyses (scenario, OWSA and PSA) were performed to assess the robustness of results.

RESULTS: In comparison to BSC, risdiplam increased LYGs (5.81) and costs (€2,005,518), resulting in an ICER of €345,217/LYG for SMA Type 1. In comparison nusinersen, risdiplam resulted in 1,92 LYGs. With lower cost for equivalent LY, risdiplam dominated OA. Risdiplam extendedly dominated nusinersen. Uncertainty analyses were sensitive to hazard ratio of overall survival and time horizon. In Type 2-3 SMA, risdiplam increased QALYs (0.34) and costs (€6,254,345), resulting in an ICER of €18 million/QALY versus BSC and extendedly dominated nusinersen based on point estimates from ITC.

CONCLUSIONS: Based on the last available information, risdiplam is projected to be a high-value treatment alternative to nusinersen and OA in France.