# Longitudinal efficacy of risdiplam treatment in Chinese children with spinal muscular atrophy

## TL;DR

This study shows that risdiplam improves motor function in Chinese children with spinal muscular atrophy, with better results in those treated earlier.

## Contribution

Provides real-world evidence of risdiplam's efficacy in SMA children in China, highlighting treatment timing impacts.

## Key findings

- CHOPINTEND scores improved significantly in 18 children after risdiplam treatment.
- HFMSE scores showed noticeable improvement in 76.5% of patients.
- Motor function improvements were faster in children with shorter disease duration or specific gene copies.

## Abstract

As the latest drug available for the treatment of spinal muscular atrophy (SMA), real-world research data on risdiplam are still lacking. The purpose of this study was to supplement the real-world data in SMA children receiving risdiplam by studying children in multiple centers throughout China.

In total, 34 children with SMA were collected from September 2021 to November 2024 and followed for a period of 8.3 ± 4.6 months. The Children’s Hospital of Philadelphia infant test of neuromuscular disorders (CHOPINTEND) scores of 18 children at the last visit improved when compared with baseline [20 (3–60) vs. 39 (8–61), p < 0.001]. Thirteen patients (76.5%) demonstrated a noticeable improvement in Hammersmith functional motor scale expanded (HFMSE) score at the last follow-up compared with baseline [22 (6–52) vs. 31 (8–59), p = 0.003]. Revised upper limb module (RULM) scores of 7 patients at the last follow-up were improved compared with those at baseline [21 (6–32) vs. 24 (9–35), p = 0.018]. Improvements in motor function were monthly quantified by generalized estimating equation analysis. The CHOPINTEND score increased by 1.8 points/month (95%CI 0.8 to 2.9, p = 0.001) in children with short disease duration before treatment, 2.7 points/month (95%CI 2.4 to 3.0, p < 0.001) in children with type 1 and 2.7 points/month (95%CI 2.1 to 3.3, p < 0.001) in patients with 2 copies of survival motor neuron 2 gene. Pneumonia was the most frequently reported adverse event, whereas laboratory tests yielded no unusual findings.

Motor ability of children with SMA were improved under risdiplam with a good safety profile. The degree of motor function improvement was related to the course of disease before treatment.