Brogidirsen Shows Sustained Motor Function Preservation in 4.5-Year Duchenne Muscular Dystrophy Trial
Key Insights
NS Pharma (search) and NCNP (search) presented 4.5-year clinical trial data for brogidirsen, an antisense oligonucleotide therapy for Duchenne muscular dystrophy (search) patients with exon 44 (search) skipping mutations.
Six participants maintained motor function scores on North Star Ambulatory Assessment and Performance of Upper Limb assessments throughout the extended treatment period.
The therapy demonstrated an acceptable safety profile with no serious adverse events related to long-term administration and no treatment discontinuations over 4.5 years.
NS Pharma (search) and the National Center of Neurology and Psychiatry (NCNP (search)) presented compelling 4.5-year clinical data for brogidirsen (NS-089/NCNP-02) at the 2026 MDA Clinical & Scientific Conference, demonstrating sustained motor function preservation in Duchenne muscular dystrophy (search) patients amenable to exon 44 (search) skipping.
The antisense oligonucleotide therapy, co-discovered by Nippon Shinyaku and NCNP (search), showed maintained motor function across multiple assessment scales in six participants who received weekly intravenous dosing throughout the extended study period.
Long-Term Efficacy Maintained
The presented data encompass results from a first-in-human Phase 1/2 open-label investigator-initiated clinical trial conducted by NCNP (search) and a subsequent Phase 2 open-label extension trial led by Nippon Shinyaku. All six participants maintained their motor function scores on the North Star Ambulatory Assessment (NSAA) from the initiation of weekly administration.
Notably, participants preserved their total scores on the Performance of Upper Limb (PUL 2.0) assessment, including those who transitioned to full-time wheelchair use due to natural disease progression. This maintenance of upper limb function represents a clinically meaningful outcome for DMD (search) patients, as upper limb capabilities are crucial for daily activities and quality of life.
Favorable Safety Profile Over Extended Treatment
After 4.5 years of brogidirsen administration, the therapy demonstrated an acceptable safety profile with no serious or severe adverse events reported in relation to long-term treatment. Importantly, no cases of anaphylaxis were observed, and no patients discontinued treatment due to safety concerns.
"We are thrilled to see the data continue to demonstrate long-term efficacy in DMD (search) patients amenable to exon 44 (search) skipping and while maintaining patient safety," said NS Pharma (search) President Yukiteru Sugiyama, Ph.D. "We are committed to expanding available treatment options to the DMD community and we look forward to realizing that ambition."
Targeting Exon 44 Skipping Mutations
Brogidirsen is designed as an investigational therapy specifically for DMD (search) patients with dystrophin gene (search) mutations that are amenable to exon 44 (search) skipping. This targeted approach represents a precision medicine strategy for addressing specific genetic variants within the broader DMD patient population.
The findings support brogidirsen's potential to modify DMD (search) disease progression, with the extension trial continuing to investigate the safety and efficacy of longer-term administration. Additionally, a second global Phase II study is currently being conducted by Nippon Shinyaku and NS Pharma (search) to further evaluate the therapy's safety and efficacy profile.
Disease Context and Unmet Need
Duchenne muscular dystrophy (search) primarily affects males and causes progressive weakness and loss of skeletal, cardiac, and respiratory muscles. Early signs include delayed ability to sit, stand, or walk, with progressive mobility loss leading to wheelchair dependence by adolescence. Cardiac and respiratory complications typically emerge during the teenage years, resulting in serious, life-threatening complications.