Sarepta Therapeutics' Eteplirsen, a treatment for duchenne muscular dystrophy (DMD), has met the primary endpoint of increased novel dystrophin and achieved significant six-minute walk test improvements after 48 weeks of treatment in a Phase IIb study.
Eteplirsen administered once weekly at either 30mg/kg or 50mg/kg for 48 weeks resulted in a statistically significant increase in dystrophin-positive fibres to 47.0% of normal.
Nationwide Children's Hospital, the Centers for Gene Therapy and Muscular Dystrophy, director and Phase IIb study principal investigator Dr Jerry Mendell said; "By addressing the underlying cause of DMD, eteplirsen has demonstrated unparalleled effects on enabling dystrophin production and slowing the progression of the disease as measured by the 6-minute walk test, with no treatment associated adverse events."
The placebo/delayed treatment cohort, which received 24 weeks of eteplirsen at either 30mg/kg or 50mg/kg following 24 weeks of placebo, also showed a statistically significant increase in dystrophin-positive fibres to 38.3% of normal.
Eteplirsen administered once-weekly at 50mg/kg over 48 weeks demonstrated an 89.4m benefit in six-minute walk test (6MWT), compared to those who received placebo for 24 weeks followed by eteplirsen for 24 weeks in the open-label extension.
The predefined prospective analysis of the study's intent-to-treat population reported that the change in 6MWT distance from baseline, eteplirsen-treated patients who received 50mg/kg of the drug weekly demonstrated an increase of 21.0m in distance walked from baseline (mean=396.0m).
Patients who received placebo/delayed-eteplirsen treatment showed a decline of 68.4m from baseline (mean=394.5m), for a statistically significant treatment benefit of 89.4m over 48 weeks, the company said.
No statistically significant difference between the cohort of patients who received 30mg/kg weekly of eteplirsen and the placebo/delayed treatment cohort was observed.
Sarepta Therapeutics president and CEO Chris Garabedian said; "On a broader scale, these results signify the promise and tremendous potential of our RNA-based technology to impact and modulate disease at the genetic level, which may lead to first-ever opportunities to target serious and life-threatening rare conditions at the origin of disease."
The study observed no treatment-related adverse events, no serious adverse events, and no discontinuations across all the subjects through 48 weeks.