P.217Patterns of disease progression in patients with spinal muscular atrophy type 3 using the motor function measure

The recent approval of Nusinersen as the first therapy for all types of spinal muscular atrophy (SMA) plus the numerous therapeutic trials underway, are quickly and deeply changing the face of the disease. These perspectives bring new challenges, including the need to timely identify responders to expensive medication. There is currently little evidence available on whether patients with longer disease duration and milder phenotypes such as adults and patients with SMA type 3 may respond to novel therapies, and few data are available on their natural decline. The objective of the present study was to characterize motor function evolution over 2 years in patients with SMA type 3 using the motor function measure scale 32 (MFM 32). This study was performed by gathering data from different existing multicentric datasets: the French MFM database, the NatHis-SMA study (a European, prospective, multicenter, longitudinal natural history study of Type 2 or 3 SMA) and the placebo arm of NCT01302600 - a phase 2, multicenter, double-blind, placebo controlled study that assessed safety and efficacy of olesoxime in 3-25 year-old SMA patients. 47 patients, aged 8.4 to 50.5 years, ambulant (n=27) and non-ambulant (n=20) were included in our study. The patients were stratified by age in groups: 6 to 11 years, 11 to 19 years and 20 years or older. We found a significant median difference of -1.04 of the total MFM 32 score for all patients over the two years of the study. This decline was present in all age groups, with no significant age group effect. The declining pattern of the MFM32 score was mainly driven by the D1 score (standing and transfer items) with mean significant difference of -3.8 points in non-ambulant patients. Changes in the MFM 32 total score and domain scores will be presented overall and by subgroup. This data adds to the understanding of progressive motor and function loss in patients with SMA type 3.