PRO14 IMPROVED QUALITY OF LIFE AND LIFE-YEARS IN PATIENTS WITH INFANTILE-ONSET SMA FOLLOWING TREATMENT WITH NUSINERSEN

Spinal muscular atrophy (SMA) is a rare, hereditary neuromuscular disorder. Newborns with infantile-onset SMA have extremely limited motor abilities and a short life expectancy. Nusinersen is the only approved treatment for SMA. The objective of this study is to develop a cost-effectiveness (CE) model to report the clinical benefits and cost-offsets of nusinersen in infantile-onset SMA (most likely to develop SMA Type I or II) from a United States (US) third-party payer perspective. A deterministic cost-effectiveness Markov model was constructed based on the ENDEAR trial, natural history data, and clinical opinions. Health states were consistent with infantile-onset SMA and based on the Hammersmith Infant Neurological Examination motor abilities scale. Disease management costs and utility values specific to the US were obtained from the literature. Life years (LYs), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) of nusinersen compared with standard of care (SOC) were reported. Over a lifetime horizon of 60 years, patients treated with nusinersen had an estimated incremental 2.22 discounted LYs compared to SOC (4.37 and 2.15, respectively), and 1.64 discounted QALYs (2.05 and 0.41, respectively). While the ICER of nusinersen versus SOC exceeded $500,000/QALY threshold for orphan drugs, the estimated incremental cost offset of direct disease management was $175,772 for patients treated with nusinersen versus SOC who had not achieved any milestones. Additionally, nusinersen compared to SOC resulted in an estimated higher proportion of patients achieving motor milestones of sitting, standing or walking with assistance (42.8% versus 3.3%) and walking unaided (21.8% versus 0%). Compared with SOC, infantile-onset patients treated with nusinersen are estimated to live longer with less disease burden than patients who received SOC. It is important to consider the clinical benefits and overall survival when assessing the value of a rare-disease treatment in order to inform clinical practice.