Risdiplam therapy in adult patients with Spinal muscular Atrophy (SMA). A 24-month-real-world experience at a single muscular centre.

Introduction: Treatment with Risdiplam has been recently extended to adult patients with Spinal Muscular Atrophy (SMA). We describe the experience of a single neuromuscular centre in Italy in treating adult SMA patients with risdiplam and analyze motor function during a follow-up period of 24 months. Patients and methods: Twelve patients with type 2 or 3 SMA (three with SMA type 3, five with SMA type 3a and four with type 3b, age range: 24-61) were included. Of them, nine were "sitter" and three were "walker"patients. The Revised Upper Limb Module (RULM) and the Hammersmith Functional Motor Scale Expanded (HFMSE) were recorded at baseline and every six months. Treatment adverse events were collected at every follow-up visit. Results: All the patients reached the 24-month follow-up. Based on the HFMSE score, 50% showed an improvement compared to the baseline total scores, 41,7% remained stable, and 8.3% experienced slight clinical worsening. Based on the RULM scores, the percentages were comparable: 50% demonstrated an improvement compared to the baseline total scores, 41,7% remained stable and 8,3% slight clinical worsening. The best results were observed in the patient "walker" group. The most common adverse events were transient gastro-intestinal problems and headache. Conclusions: Our study confirms that risdiplam is well tolerated. Half of the patients improved after risdiplam initiation and about 42% remained stable. Most patients stated to be satisfied with the medication. Longitudinal studies are needed to better understand the long-term effects of risdiplam in adult SMA.