Goal Attainment Scale light captures clinically meaningful changes in Adolescents and Adults with Spinal Muscular Atrophy Treated with Risdiplam

Introduction/Aims To evaluate the usefulness of the Goal Attainment Scale (GAS) light for assessing response to risdiplam in patients with SMA aged [≥]15 years. Methods In this population-based, longitudinal, ambispective study, patients were evaluated before and at 12 and 24 months after risdiplam initiation using motor scales (SMA Functional Composite Score Revised [SMA-FCR]), pinch strength (MyoPinch), functional scales (EK2, ALSFRS-R), patient and clinician global impression of change (PGIC and CGIC), and GAS light. Longitudinal changes were assessed using linear mixed-effects models. The minimal detectable change (MDC) and minimal clinically important change (MCIC) of GAS light were calculated. Results Forty-four patients (median age 32 years; 56.8% female) were included: 31.8% non-sitters, 56.8% sitters, and 11.4% walkers. GAS light priorities differed across functional subgroups, with patients prioritising moderately affected domains. After 24 months of risdiplam treatment, motor outcomes showed non-significant improvements in walkers, whereas functional scales improved significantly only in non-sitters. In contrast, GAS light detected significant, increasing improvements across all functional subgroups. The MCIC and MDC for GAS light were 6.5 and 10.65 points, respectively. According to the CGIC, 58% of patients improved slightly, 29% remained stable, and 13% worsened slightly at 24 months. Using the MCIC threshold, 64.5% achieved clinically meaningful goal improvement. Discussion GAS light is a feasible, sensitive, patient-centred tool that may complement standardised outcome measures when evaluating treatment response in adults with SMA. These findings further support risdiplam as a valuable therapeutic option in this population.