Cost-effectiveness of treatments for presymptomatic newborn patients with spinal muscular atrophy and two or three copies of the survival motor neuron 2 gene in Italy.

Objective: We assessed the cost effectiveness of onasemnogene abeparvovec (OA) for presymptomatic infants with two or three copies of the survival motor neuron 2 (SMN2) gene (diagnosed/treated ≤ 6 weeks old) who lack functional SMN1 gene (biallelic SMN1 mutations). This cost-utility model compared three disease-modifying treatments and best supportive care (BSC) (scenario analysis) in an Italian setting.

Methods: For a cohort of 1000 children, a Markov model simulated costs and benefits of OA (a one-time treatment), nusinersen and risdiplam (continuous lifelong treatments), and BSC. A lifetime time horizon (up to age 100 years) was applied, and the perspective of the Italian National Health Service was considered. Results are reported as incremental cost-effectiveness ratios (ICERs). Deterministic and probabilistic sensitivity analyses were conducted to assess the robustness of the model and validity of results.

Results: In the full cohort, OA was dominant (less costly, more effective) compared with nusinersen or risdiplam (ICERs,-€4,562,815 and-€718,640), and cost effective (more costly, more effective) compared with BSC (ICER, €65,894). Similar results were found for patients with two SMN2 copies. For patients with three SMN2 copies, OA was less costly, with a similar efficacy profile compared with nusinersen, dominant versus risdiplam, and cost effective compared with BSC. Probabilistic sensitivity analysis demonstrated the robustness of the model and validated deterministic sensitivity analysis results for the full cohort.

Conclusions: OA for the treatment of presymptomatic newborns was dominant or cost effective compared with other treatments or BSC in the full patient cohort within the Italian context.