Viltolarsen linked to increased pulmonary function in Duchenne muscular dystrophy

Key takeaways:

• Mean change from baseline in pulmonary function for patients treated with viltolarsen improved at week 48.
• No participants in either group discontinued, no serious adverse events or deaths were reported.

Treatment with viltolarsen at 48 weeks improved pulmonary function in a cohort of pediatric patients with Duchenne muscular dystrophy amenable to exon 53 skipping compared with those receiving standard care.

“Decline in pulmonary function is a concern for patients with Duchenne muscular dystrophy,” Amy D. Harper, MD, director of the neuromuscular clinic at Children’s Hospital of Richmond at Virginia Commonwealth University, and colleagues wrote in a poster from the 2024 MDA Clinical & Scientific Conference. “Viltolarsen is indicated for the treatment of DMD in patients with dystrophin mutations that are amenable to exon 53 skipping.”

Previous studies demonstrated viltolarsen’s ability to be well tolerated and to increase dystrophin levels, stabilize motor function over 4 years, yet its ability to increase pulmonary function was not evaluated, researchers aimed to evaluate the drug’s forced vital capacity (FVC) in a phase 2 clinical trial.

This 48-week study evaluated safety, motor and pulmonary function in 20 ambulant and non-ambulant participants with DMD (mean age, 12.8 ± 5.47 years; 50% non-ambulatory) given 80 mg/kg per week of viltolarsen.

The primary outcome for the study was percent predicted FVC (FVC%p) while accounting for age and height, in participants treated with viltolarsen compared with participants treated with standard of care from the CINRG Duchenne Natural History Study (n = 48; mean age, 12.7 ± 4.05 years; 48% non-ambulatory). Matching was done with respect to age, ambulatory, pulmonary and steroid status.

According to results, the mean change from baseline in FVC%p for participants treated with viltolarsen- (5.15 ± 2.3) was significantly improved at week 49 compared with the DNHS cohort (0.93 ± 1.5).

In the safety population, 19% of viltolarsen-treated participants reported a treatment-emergent adverse event, with four events classified as drug-related. No participants in either group discontinued and no serious adverse events or deaths were reported.

“The data suggest that ... viltolarsen can be considered an important part of the treatment strategy for patients with DMD amenable to exon 53 skipping therapy,” Harper and colleagues said.