Cost‐utility analysis of nusinersen–risdiplam switch in patients with spinal muscular atrophy in Croatia: A discrete event simulation model

Introduction In recent years, the treatment of spinal muscular atrophy (SMA), a rare disease, has significantly progressed, improving patients' survival and overall quality of life. However, current SMA treatments are expensive, and some (nusinersen) are very inconvenient for patients. There is reason to believe that there are economic benefits of switching patients from nusinersen to risdiplam, especially because real‐world analysis has shown non‐inferiority in clinical outcomes along with a favourable safety profile of switching. Aim To conduct the cost‐utility analysis of switching from nusinersen to risdiplam. Methods A discrete event simulation model was created for three different groups of patients with SMA (types 1–3), comparing the cost‐utility of nusinersen to the risdiplam switch and continuing nusinersen therapy. Analysis was conducted from the perspective of the Croatian Health Insurance Fund for the time horizon of 80 years. A deterministic, one‐way, one‐factor sensitivity analysis was carried out using the Monte Carlo simulation. Results The incremental cost‐effectiveness ratio of nusinersen to risdiplam switch versus staying on nusinersen was EUR‐136930 ± 82 336 for type 1 SMA (i.e. the switch dominated), for type 2 SMA it was EUR 2681860 ± 321 859, and for type 3 SMA it was EUR 2576667 ± 676 078. For all three types of SMA, switching to risdiplam showed positive net monetary benefit (type 1: EUR 35449 ± 17 113; type 2: EUR 799264 ± 30 765; type 3: EUR 767498 ± 7283). Market forces may substantially impact pricing dynamics; therefore, these results should be interpreted with consideration of inherent uncertainties. Conclusion The cost‐effectiveness of switching from nusinersen to risdiplam is evident across all SMA types. Further research on the long‐term impact of switching treatments in SMA is essential to address uncertainties and optimize cost‐effective therapeutic strategies.