Effectiveness of Risdiplam Treatment in Adult Patients With Spinal Muscular Atrophy Type IIb–III

Introduction: Risdiplam is a pharmacological agent developed for the treatment of spinal muscular atrophy (SMA) associated with 5q deletion, with the therapeutic objective of increasing the concentration of the survival motor neuron 2 protein. Most clinical trials and real-world studies have focused on pediatric and young adult populations. Our aim was to assess the effectiveness of risdiplam treatment in adult patients with SMA type IIb and III. Methods: We studied 8 adult patients with SMA (3 females/5 males). Patient functionality was assessed using the Egen Klassifikation version 2 (EK2) scale, upper limb function with the 9-hole peg test (9HPT, seconds), and respiratory function with peak flow (L/min) and sniff nasal inspiratory pressure (SNIP, cmH2O). Plasma levels of neurofilament light chain (NFL, pg/mL) and glial fibrillary acidic protein (GFAP, pg/mL) were also measured. Patients were evaluated at baseline, and after 6 and 12 months of treatment. Results: The median age was 55 years (range: 41–66). At 12 months, EK2 scores showed a trend toward improvement in swallowing [item 16] (p = 0.06), peak flow increased significantly (244 ± 112 vs. 259 ± 124 L/min, p = 0.036), and there was a trend toward decreased NFL levels (11.4 ± 4.9 vs. 9.4 ± 2.7 pg/mL, p = 0.093). Both NFL and GFAP concentrations were negatively correlated with peak flow and SNIP values. Conclusions: In our series, treatment with risdiplam may stabilize adult patients with type IIb–III SMA.