140P Need for tube feeding in SMA type I patients treated with disease modifying therapies: bulbar function before treatment matters

Abstract

The advent of disease-modifying therapies has reduced the risk to develop bulbar difficulties that were invariably found in untreated infants with type I SMA. The aim of this study was to assess possible longitudinal patterns of swallowing abilities in a cohort of treated infants with type I SMA and to identify factors that may predict bulbar outcome. The cohort includes 75 type I infants, one with 1, 63 with 2 and 11 with 3 SMN2 copies treated at an age ranging between 0.06 and 4.98 years (mean 1.34). Follow-up after treatment ranged between 1 and 7.66 years. Sixty-nine patients were treated with Nusinersen, with 18/69 subsequently switching to onasemnogene abeparvovec and another 6 patients only received onasemnogene abeparvovec. All patients were classified at baseline, when treatment started, and at follow-up according to their functional bulbar level and the need for tube feeding. At the last follow-up, 36/75 (48%) had no need for tube feeding and 39 had gastrostomy. Seven of the 39 who had tube feeding were also able to be fed by mouth. Twenty-nine of the 39 infants with tube feeding at follow-up already had bulbar difficulties when treatment was started. The level of bulbar involvement measured by the OrSAT levels was significantly associated with bulbar outcome (p=<.001). Other factors, such as a reduced SMN2 copy number (1 or 2 copies), SMA type 1.1 subtype or treatment started at a later age were also related to an increased risk of tube feeding but the association was not significant.