145P Efficacy of SMA NBS: 4-year comparative study with control group

Several newborn screening (NBS) programs for Spinal Muscular Atrophy (SMA) have demonstrated feasibility-reliability and short-term efficacy of PCR-based universal SMA NBS, but longer-term data are needed to precise the benefit of this intervention. In addition, the comparison with external control groups can reinforce the level of evidence and support robust health economic assessment. The aim of this study is to compare the medical, quality of life and economic data for SMA patients diagnosed by NBS and those identified by symptoms, in the same country, during the same time period. We collected data on all SMA patients born in Flanders and the Wallonia-Brussels Federation (FWB) between January 1, 2019 (the date on which the entire FWB began screening for SMA) and 30 November 2022 (the date on which Flanders began screening). We compared the median age of diagnosis and initiation of treatment, the treatment, scores on motor development scales, and the age of acquisition of sitting and walking. We also collected quality of life data for parents, utility data for children, and costs associated with the disease. A total of 30 patients were included in the analysis: 16 patients in FWB (7 with 2 SMN2 copies, 4 with 3 copies and 5 with 4 copies) and 13 in Flanders. One patient with a point mutation was not identified by NBS in FWB. Patients in FWB were initially treated by nusinersen (n = 5) risdiplam (n = 3) and onasemnogene abeparvovec (n = 7) at 36 days of life on average (29, 37, and 44 days respectively for patients with 2, 3 and 4 SMN2 copies of SMN2). Two patients shifted from nusinersen to risdiplam, one from nusinersen to onasemnogene abeparvovec and one from risdiplam to onasemnogene abeparvovec. One patient with 4 SMN2 copies was still untreated at 26 months. Median follow up was 32 months (9-54 months). All patients over 18 months with 3 and 4 SMN2 copies acquired ambulation (median age: 17 months, 13-24 months). Of the 7 patients with 2 SMN2 copies, 2 are not yet 18 months old, 4 are walking, and one aged 24 months is not yet walking. One child with 2 SMN2 copies have non-invasive nocturnal ventilation. None of the children needed nutritional support at the time of the last follow-up. Data in Flanders, where NBS was not implemented in the studied time, are currently collected, and will be presented during the congress. Our data shows that middle term outcome of patients identified by NBS is very good so far. Estimation of health care cost saving will be presented.