Background: Viltolarsen became commercially available in the US in August 2020 and is indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients with a mutation amenable to exon 53 skipping. With 4 years of real-world viltolarsen patient data available, a database analysis was performed to better understand their experience.
Methods: A patient-level analysis was conducted on an integrated data set consisting of internal patient data as well as specialty pharmacy dispense and status data from launch (August 2020) to the most current time point (November 2024).
Results: Mean age at viltolarsen treatment initiation was 12.4 years (range: 1–30 years); 6% of patients receiving viltolarsen began treatment under 4 years of age, and 60% were ≥10 years old at initiation. Over 30% of patients receiving viltolarsen switched from another exon skipping therapy. Since viltolarsen launch, the number of days from enrollment in the patient support program to first infusion was reduced by 46%. Younger patients (<13 years) and patients switching from another exon-skipper (vs exon skipping naïve patients) experienced the shortest approval time. In a cohort analysis of patients who had the opportunity to be on therapy for ≥3 years, 77% stayed on viltolarsen for 3 years or longer. Patients receiving viltolarsen followed the prescribed dosing treatment regimen at a rate of 93% as calculated according to medication possession ratio methodology. Conclusion: This analysis of real-world patient data describes viltolarsen treatment in a broader age range than that of the Phase 2 trial population, providing practical information regarding the use of viltolarsen at different points in the patient journey. The mean time to first infusion was fastest for patients switching exon skipping therapies who had already gone through the approval process and for younger patients. Persistence and compliance were strong, having implications for efficacy and safety.