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

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.

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.

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.

In our series, treatment with risdiplam may stabilize adult patients with type IIb-III SMA.