SMA: REGISTRIES, BIOMARKERS & OUTCOME MEASURES: P.187 Systematic literature review of the economic burden and economic evaluations in spinal muscular atrophy

New treatments in spinal muscular atrophy (SMA) have led to a complete change in the pattern in the use of health care resources in this disease. Through all over the world, the very high cost of innovative medication has led to public debates largely expressed in mainstream medias. We have systematically reviewed studies evaluating the cost of SMA and economic evaluations of spinal muscular atrophy. The review was conducted according to PRISMA guidelines and included original articles published between January 1, 1998 and March 2020. Seven studies reporting the cost of SMA were identified. The average annual costs of untreated SMA1 (including early onset and SMA before one year), were relatively similar across the different studies, ranging from $106,000 to $140,000 per year. On the other hand, the costs for SMA 2, 3 and 4 were mainly presented together (ranging from $23,000 to $115,000), despite a high heterogenicity in clinical conditions leading to very different health care resource consumption. Five economic evaluations were published between 2017 and 2020 and included innovative disease modifying medications. Three assessed the cost-effectiveness of nusinersen against standards of care, one of them two treatments (nusinersen and zolgensma) against standards of care and one compared Nusinersen and Zolgensma. All studies used a decision-analytic model to assess the cost- effectiveness and are based on same clinical trials involving a limited number of patients. Due to the extremely high cost of treatment, the incremental cost-effectiveness ratio of drugs versus no treatment is generally above $200,000, leading to no cost-effective results. In conclusion, all studies converge to demonstrate the significant economic cost of SMA, especially SMA1, but a better evaluation of the cost related to other forms is needed. A few economic evaluations suggest that drugs delivered in post-symptomatic phase at current prices are actually not cost-effective at commonly accepted cost-effectiveness threshold. No economic evaluation of newborn screening has yet been conducted.