Spinal muscular atrophy (SMA) is a rare genetic condition that affects muscle strength and movement in both children and adults. Two treatments, nusinersen (Spinraza) and risdiplam (Evrysdi), are publicly reimbursed in Canada, primarily for use in children. The Canadian Drug Expert Committee (CDEC) reimbursement recommendations for both drugs highlighted serious limitations in the evidence for the effectiveness and safety of these treatments in adults with SMA. In particular, the evidence is limited by the lack of high-quality, comparative data, making it difficult to determine whether observed effects are due to the drugs or to other factors, and whether these effects are clinically meaningful in adults. As a result, reimbursement recommendations issued by CDEC do not support treatment initiation of nusinersen in patients older than aged 18 years or initiation of risdiplam in patients aged older than 25 years.
