Background: Spinal Muscular Atrophy (SMA) is a rare, genetic, neuromuscular disease characterized by progressive muscular atrophy and weakness. The Revised Upper Limb Module (RULM) assesses the upper limb function in patients with SMA. It includes 19 items graded on a 3-point system that are closely associated with meaningful activities of daily living. Assessing the abilities gained or lost in the individual items of the RULM can help understand clinically relevant changes in SMA patients.
Objectives: To examine the longitudinal changes in the individual items of the RULM scale in participants with later-onset SMA treated with nusinersen in CHERISH/SHINE.
Results: One-hundred fourteen participants with Day 930 visit data (i.e., 2.5 years after nusinersen initiation) were included (27 August 2019 data cut). The mean scores of all 19 items increased from baseline (nusinersen initiation) to Day 930 except reaching to the side (mean difference [MD]: -0.03) and bringing hands from lap to table (MD: 0.0). The items with the highest mean increase were lifting a 500g weight (MD: 0.52) and tearing paper (MD: 0.52). For a shift analysis from baseline to Day 930, gain of an activity was defined as a positive change in each item score from 0 (unable) to either 1 (able, with modification) or 2 (able, no difficulty); loss was defined as a negative change from either 2 or 1 to 0. At Day 930, tearing paper (46%), pushing a button light with one hand (33%), and opening a Ziploc container (25%) were the most frequent items to be gained. Those younger at baseline (age ≥2.0 to ≤3.5 years) gained more activities than those older at baseline (≥5.0 to <9.5 years). Across all age groups, there were more gains in activities than losses. Conclusions: Longitudinal changes in the individual items of the RULM scale may help understand clinically relevant changes on important activities of daily living in patients with later-onset SMA treated with nusinersen. Study Support: Biogen