Viltolarsen Treatment of Muscular Dystrophy Improves Mobility Over More Than 2 Years

Interim analyses of an open-label extension trial (NCT04337112) have shown mobility improvement in individuals with Duchenne muscular dystrophy (DMD) after 109 weeks of treatment with viltolarsen (Viltepso; NS Pharma, Paramus, NJ). Improvements seen are statistically signficant as compared with the natural history cohort evaluated in the Cooperative International Neuromuscular Research Group (CINRG)-DMD study (Table).  

“These analyses showed that, after more than 2 years of treatment with Viltepso, patients maintained their motor function based on clinically relevant measurements while the DMD historic controls showed functional decline,” said Leslie Magnus, MD, vice president of Medical Affairs. 

The current open-label trial (n=16) is an extension of a previous 24-week trial with 16 participants from the phase 2 short-term study who elected to enroll in this long-term trial. Participants were assessed during the 37, 49, 73 and 109 weeks and will be continue to be assessed throughout the entirety of the study. These interim analyses of timed function tests were conducted for all participants who had received 109 weeks of viltolarsen treatment vs participants from the matched CINRG-DMD cohort.  

Alongside the phase 2 open-label extension study, the investigation of the efficacy and safety of viltolarsen in the confirmatory phase 3 RACER53 trial (NCT04768062) continue and is actively enrolling participants with DMD amenable to exon 53 skipping.

“Duchenne is a progressive disease of functional deterioration,” said study investigator Paula Clemens, MD, University of Pittsburgh Medical Center. “More research is needed, but a disease-modifying therapy that could stabilize and delay the loss of muscle function is needed for families with Duchenne. . .”
  
The most frequently reported adverse events were cough, nasopharyngitis, rash, pyrexia, and vomiting. To date, no treatment-related serious adverse events and no treatment discontinuations have occurred.