BACKGROUND: Spinal muscular atrophy (SMA) is a rare neuromuscular disorder with a spectrum of severity related to age at onset and the number of SMN2 gene copies. Infantile-onset (≤6 months of age) is the most severe and is the leading monogenetic cause of infant mortality; patients with later-onset (>6 months) can survive into adulthood. Nusinersen is a new treatment for SMA.
OBJECTIVE: The objective of this study was to evaluate the cost-effectiveness of nusinersen for the treatment of patients with infantile-onset SMA and later-onset SMA in Sweden.
METHODS: One Markov cohort health-state transition model was developed for each population. The infantile-onset and later-onset models were based on the efficacy results from the ENDEAR phase 3 trial and the CHERISH phase 3 trial, respectively. The cost-effectiveness of nusinersen in both models was compared with standard of care in Sweden.
RESULTS: For a time horizon of 40 years in the infantile-onset model and 80 years in the later-onset model, treatment with nusinersen resulted in 3.86 and 9.54 patient incremental quality-adjusted life-years (QALYs) and 0.02 and 2.39 caregiver incremental QALYs and an incremental cost of 21.8 and 38.1 million SEK (Swedish krona), respectively.
CONCLUSION: Treatment with nusinersen results in overall survival and QALYs benefits but with incremental costs above 21 million SEK (mainly associated with maintenance treatment with nusinersen over a patient’s lifespan), which translate into incremental cost-effectiveness ratios (including caregiver QALYs) of 5.6 million SEK and 3.2 million SEK per QALY gained in the infantile-onset model and later-onset model, respectively.
