NS Pharma’s brogidirsen (NS-089/NCNP-02) is an investigational therapy for Duchenne muscular dystrophy (DMD) designed for patients with dystrophin gene mutations amenable to exon 44 skipping. Five-year efficacy and safety data from the clinical development of brogidirsen were presented at the 31st annual International Congress of the World Muscle Society, held in Hiroshima, Japan, from September 29 to October 3, 2026.
NS Pharma, Inc., headquartered in Paramus, New Jersey, is a biopharmaceutical company focused on rare diseases and a subsidiary of Nippon Shinyaku Co., Ltd., headquartered in Kyoto, Japan. Brogidirsen was co-discovered by Nippon Shinyaku and the National Center of Neurology and Psychiatry (NCNP) as an investigational treatment for DMD patients whose genetic mutations are amenable to exon 44 skipping. Learn More: Mutations and Deletions Amenable to Exon 44 Skipping Therapies
The newly presented results come from an investigator-initiated clinical trial conducted by NCNP and its open-label extension study conducted by Nippon Shinyaku. The studies evaluated the efficacy and safety of brogidirsen in six participants who received weekly intravenous (IV) dosing.
Motor Function Maintained Over Five Years
One of the key findings was the maintenance of motor function among participants who remained ambulant during the study. The evaluation showed that motor function was maintained or improved in these participants.
Upper limb function was also maintained in all participants, including those who became non-ambulant during the course of the study. These findings were part of the five-year evaluation of participants receiving long-term brogidirsen treatment.
The results provide clinical data on functional outcomes over an extended period of treatment and suggest the potential for brogidirsen to slow disease progression in patients with DMD who are amenable to exon 44 skipping.
No Serious or Severe Treatment-Related Adverse Events Reported
The five-year safety findings were another important part of the presentation. After receiving brogidirsen for five years, participants did not experience serious or severe adverse events related to long-term brogidirsen administration.
The study also reported no treatment-related anaphylaxis, and there were no discontinuations during the five-year period.
According to the presented data, these findings indicate an acceptable safety profile for long-term administration within the participants evaluated in the study.
Comparison With DMD Natural History
The investigators also compared several functional measures with natural history data for DMD. In several measures, the functional outcomes observed in the study compared favorably with the natural history of the disease.
The company stated that the findings suggest brogidirsen may have the potential to slow disease progression in DMD patients whose mutations are amenable to exon 44 skipping.
However, the extension trial is still ongoing. The study will continue to investigate the efficacy and safety of long-term brogidirsen administration.
Global Phase II Study Underway
In addition to the ongoing extension study, Nippon Shinyaku and its subsidiary NS Pharma are conducting a global Phase II study of brogidirsen.
The five-year data presented at the World Muscle Society Congress provide longer-term clinical information from six participants treated with weekly IV brogidirsen. The results include observations on motor function, upper limb function, safety, and comparisons with DMD natural history data.
Brogidirsen remains an investigational therapy, and the ongoing studies will provide additional information about its efficacy and safety in patients with DMD who are amenable to exon 44 skipping.
Discover More: Duchenne Clinical Trial Locations Map
