“This data represents the longest-running clinical trial of exon 53 skipping therapy for Duchenne muscular dystrophy,” Leslie Magnus, MD, vice president of medical affairs for developer Viltepso. NS Pharma (a subsidiary of Nippon Shinyaku), said in a press release.
Duchenne muscular dystrophy is caused by mutations in the gene that provides instructions for making the protein dystrophin. Viltepso drives the molecular machinery of the cell to skip this region when the gene is ‘read’, allowing the production of a shortened but functional version of dystrophin. In about 8% to 10% of cases, the disease-causing mutation is amenable to skipping 53.
The treatment was granted conditional approval in the United States in 2020 based on data from a Phase II Clinical Trial (NCT02740972) which included 16 boys with muscular dystrophy, aged 4 to 9 years at the start of the study.
Participants were given either a low dose (40 mg/kg) or a high dose (80 mg/kg) of Viltepso once weekly for six months and the results showed that they can Increased levels of dystrophin protein. At the end of the trial, all participants continued to Open Label Supplement (NCT03167255) And he got Viltepso.
Long-term results up to 216 weeks (over four years) were presented at the 27th Annual International Hybrid International Congress of the World Muscle Society (WMS 2022), Halifax, Nova Scotia, Canada.
To evaluate its efficacy, the results of boys treated with Viltepso were compared with those of a group of clinically similar boys in the Duchenne International Collaboration on Neuromuscular Research Group. (CINRG DNHS; NCT00468832). All were treated with steroids according to standard guidelines.
Over four years, the average time it took for boys to stand increased by 8.3 seconds in the control group, compared to 2.7 seconds for boys treated with Feltypso — a significant difference in preference for exon-skipping treatment.
The median time to run or walk 10 meters (just over 30 feet) increased by 2 seconds among boys who got Viltepso, compared to 6 seconds in the control group. The time to climb the four stairs also showed significant improvements compared to the control group.
In this four-year study, patients with Filtipso were treated Preservation of motor function during the first two years of treatment It experienced a significant delay in disease progression over the next two years, compared to the CINRG DNHS control group that regressed over the same time period,” Magnus said.
Viltepso’s security profile during the extension trial was similar to what was previously reported. There were no serious side effects related to the treatment, and no patients discontinued treatment due to side effects. The most commonly reported side effects included cough, colds, rash, fever and vomiting.
“This long-term study gives clinicians treating patients with muscular dystrophy and hematopoiesis important information about the long-term effect of Feltipso on improving the course of the disease,” said Paula Clemens, MD, of the University of Pittsburgh School of Medicine.
NS Pharma is sponsoring a Phase 3 trial called RACER53 (NCT04060199) to further evaluate the safety and efficacy of Viltepso in boys with Duchenne muscular dystrophy with two exon 53 skippers. The study recruits boys, aged 4 to 7 years, in Sites around the world.
“these [long-term Phase 2] The data are encouraging as NS Pharma continues to evaluate the effect of Viltepso on improving or stabilizing motor function in a Phase 3 study,” Magnus said.
“More study is underway, but these four years of data give confidence that Viltepso can be considered an important part of the treatment strategy for patients with DMD for whom dystrophin mutations are amenable to treatment,” Clemens said.