Objectives: This study aims to systematically collect data on cost-effectiveness analyses that assess technologies to treat type I and II spinal muscular atrophy and evaluate their recommendations.

Methods: A structured electronic search was conducted in 4 databases. Additionally, a complementary manual search was conducted. Complete economic studies that evaluated nusinersen, risdiplam, onasemnogene abeparvovec (OA), and the best support therapy (BST) from the health system's perspective were selected. The incremental cost-effectiveness ratios were compared with various thresholds for the analysis. The review was registered a priori in PROSPERO (CRD42022365391).

Results: Twenty studies were included in the analyses. They were all published between 2017 and 2022 and represent the recommendations in 8 countries. Most studies adopted 5, 6, or 10-state Markov models. Some authors took part in multiple studies. Four technologies were evaluated: BST (N = 14), nusinersen (N = 19), risdiplam (N = 5), and OA (N = 9). OA, risdiplam, and nusinersen were considered inefficient compared with the BST. Risdiplam and OA were generally regarded as cost-effective when compared with nusinersen. Because nusinersen is not a cost-effective drug, no recommendation can be derived from this result. Risdiplam and OA were compared in 2 studies that presented opposite results.

Conclusions: Nusinersen, risdiplam, and OA are being adopted worldwide as a treatment for spinal muscular atrophy. Despite that, the pharmacoeconomic analyses show that the technologies are not cost-effective compared with the BST. The lack of controlled studies for risdiplam and OA hamper any conclusions about their face-to-face comparison.