OBJECTIVES: Considering the growing number of prescriptions of innovative therapies for Spinal Muscular Atrophy (SMA) (nusinersen [2017], onasemnogene abeparvovec [2019] and risdiplam [2020]) in France, the EPI-SMA study aimed to provide real-world data on the epidemiology, management of therapeutic options, patient journeys, costs and impact on overall survival from 2011 up to 2022.

METHODS: Patients with at least one hospital stay related to SMA (ICD10 codes G120, G121, G128 and G129) or treated with SMA specific therapies between 2011 and 2022 were studied. Due to the absence of SMA severity registration in the SNDS, clinical algorithms were defined with experts to classify SMA patients into the three classical severity groups (SMA1-like, SMA2-like, SMA3-like). Healthcare pathways were analyzed using process mining to generate the most representative pathways for each cohort (by type, and stratified for patients treated vs not treated).

RESULTS: A total of 1,450 patients were codified as SMA in the SNDS, including 703 incident cases between 2011 and 202: 377 SMA1-like, 130 SMA2-like and 196 SMA3-like. Among treated patients, the probability of 1-year survival was 91% for SMA1-like, 100% for SMA2-like, and 99% for SMA3-like (respectively 11%, 72% and 93% for not treated patients). For the 116 SMA1-like treated patients, about 60% received nusinersen (either as first event post inclusion or after a respiratory complication), and 34% received the gene therapy. For SMA2-like and SMA3-like treated, the first event was mostly either the initiation of treatment or the implementation of mobility support. The total reimbursement costs (all incident patients) during the first year of follow-up were €804,223 for SMA1-like, €591,564 for SMA2-like and €225,037 for SMA3-like.

CONCLUSIONS: This real-world study confirms that SMA therapies have significantly impacted the healthcare pathways of SMA patients, particularly those with the most severe patients (SMA1-like), and have contributed to increased overall survival.