Viltepso improves motor function in patients with Duchenne muscular dystrophy

Viltepso, an injection treatment for Duchenne muscular dystrophy in patients with a confirmed mutation, demonstrated a statistically significant benefit for motor function in open-label extension results from a phase 2 study.

Viltepso (viltolarsen, NS Pharma) resulted in a statistically significant benefit for the primary endpoint of time to stand at multiple points during a 2-year period when compared with patients with Duchenne muscular dystrophy in a historical control group, according to a press release. Viltepso also provided “consistent and statistically significant” benefits regarding the secondary endpoints of time to run/walk and 6-minute walk test.

Researchers presented the results at the Parent Project Muscular Dystrophy 2021 Annual Conference, according to a press release.

The open-label trial, which includes 16 participants, is an extension of a prior 24-week trial conducted in North America. All patients from the previous trial enrolled in the extension trial, according to the press release. Results presented at the meeting included participants who were evaluated at weeks 37, 49, 73 and 109; further assessment is ongoing. Researchers evaluated timed function tests in the interim analysis among all participants who had been treated with Viltepso for at least 109 weeks compared with the historical control group.

Efficacy results included time to stand from supine at weeks 73 and 109, time to run/walk 10 meters at weeks 49, 73 and 109, and the 6-minute walk test at week 109. Researchers evaluated all these endpoints as the mean change from baseline.

The mean change in time to stand, as measured in seconds, was 0.21 at week 73 and 0.43 at week 109 for patients treated with Viltepso compared with 3.6 and 4.3, respectively, in historical controls (P < .01), according to the press release. Study results demonstrated a mean change in time to run/walk, as measured in seconds, of -0.8 at week 49, -0.9 at week 73 and -0.4 at week 109 for patients who received Viltepso compared with 0.5, 1.3 and 1.3, respectively, in historical controls (P < .05). Patients treated with Viltepso demonstrated a mean change from baseline in the 6-minute walk test, as measured in meters, of 0.9 at week 109 compared with -65.6 for historical controls (P < .05).

The most commonly reported adverse events during this time period, which were mild to moderate, included cough, nasopharyngitis, rash, pyrexia and vomiting, according to the press release. Researchers noted that the safety profile reported here was similar to that observed in the prior short-term study. Additionally, no treatment-related serious adverse events or treatment discontinuations have been reported to date.

The FDA first approved Viltepso for patients with Duchenne muscular dystrophy and a verified mutation on the Duchenne muscular dystrophy gene that is amenable to exon 53 skipping, which is present in approximately 8% of patients, in 2020.

“[Duchenne muscular dystrophy] is a progressive disease of functional deterioration,” Paula R. Clemens, MD, vice chair of veterans affairs and professor in the department of neurology at the University of Pittsburgh School of Medicine and division chief of neurology for the medical service line at the Veterans Affairs Pittsburgh Healthcare System, said in the press release. “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 muscular dystrophy] and the health care professionals who specialize in its treatment.”

Reference:

NS Pharma. Viltepso (viltolarsen) injection: Long-term efficacy and safety data presented at the PPMD 2021 virtual annual conference. Available at: https://www.nspharma.com/pdfs/NSPharma_Long-term_Data_PPMD_New.pdf. Accessed July 1, 2021.