Nippon Shinyaku's subsidiary, NS Pharma, has announced the publication of Phase II trial (Galactic53) data for VILTEPSO® (viltolarsen) injection in Scientific Reports, providing new insights into its efficacy in treating Duchenne muscular dystrophy (DMD). The open-label, multicenter study is the first to evaluate viltolarsen's impact on pulmonary function in DMD patients.
Galactic53 Trial Design and Outcomes
The Galactic53 trial involved ten ambulatory and ten nonambulatory males, aged eight years and older, all with confirmed deletions of the dystrophin gene amenable to exon 53 skipping. Participants received 80 mg/kg of viltolarsen intravenously once weekly for 48 weeks. The primary endpoint focused on safety, while secondary endpoints assessed pulmonary and motor function, comparing results against natural history data from matched controls.
Safety and Tolerability
The study reported that all treatment-emergent adverse events were mild to moderate. Only four events were considered treatment-related, and no participants discontinued the trial due to adverse effects. This safety profile aligns with previous studies of viltolarsen.
Pulmonary Function Improvements
Both ambulatory and nonambulatory participants treated with viltolarsen showed improvements in pulmonary function. Specifically, they exhibited higher percent predicted forced vital capacity (FVC%p) and peak cough flow (PCF) at Week 49 compared to the control group. Among ambulatory participants, 90% (nine out of ten) experienced an increase or stabilization in FVC%p from baseline, with all maintaining FVC%p values above 50% at Week 49. Similarly, 90% of nonambulatory participants saw an increase or stabilization in FVC%p from baseline, and 60% maintained FVC%p values above 50% at Week 49.
Motor Function Maintenance
Upper limb motor function, measured by Performance Upper Limb (PUL2.0) scores, remained stable throughout the 48-week treatment period in both ambulatory and nonambulatory participants treated with viltolarsen.
Viltolarsen's Regulatory Status
VILTEPSO® received approval in the U.S. in August 2020 and in Japan in March 2020 for DMD patients amenable to exon 53 skipping therapy. It holds several designations, including Priority Review, Rare Pediatric Disease, Orphan Drug, and Fast Track Designations in the U.S., and SAKIGAKE designation and orphan drug designation in Japan.
About Duchenne Muscular Dystrophy
Duchenne muscular dystrophy is a progressive genetic disorder primarily affecting males, characterized by muscle weakness and loss of skeletal, cardiac, and respiratory function. Early symptoms include delayed motor skills, progressive mobility loss, and eventual need for wheelchair assistance. Cardiac and respiratory complications typically arise in the teenage years, leading to life-threatening conditions. NS Pharma emphasizes the importance of continued research and treatment options for this debilitating disease.
