Drisapersen: Additional Phase IIb data

Additional data from the double-blind, international Phase IIb DMD114117 trial in 53 ambulant boys >5 years of age with DMD showed that intermittent dosing with subcutaneous 6 mg/kg drisapersen for 6 weeks of a 10-week cycle led to a mean increase of 3.51 meters in 6MWD from baseline to week 24, the primary endpoint, over placebo (p=0.801). GlaxoSmithKline previously reported that continuous dosing with once-weekly subcutaneous 6 mg/kg drisapersen met the primary endpoint, while intermittent dosing did not. Specifically, continuous dosing with drisapersen led to a mean increase of 35.09 meters in 6MWD over placebo (p=0.014) (see BioCentury, April 15).

On secondary endpoints, drisapersen increased dystrophin levels from baseline at week 25 as measured by >=1 testing method - immunofluorescence assay, western blot or exon skipping - in 72% of patients receiving continuous dosing and 59% of patients receiving intermittent dosing vs. 6% for placebo. From baseline to week 25, drisapersen led to a mean reduction in total muscle strength of 7.225 lbs over placebo in the continuous dosing arm and 7.99 lbs over placebo in the intermittent dosing arm. From baseline to week 49, drisapersen led to a mean reduction in total muscle strength of 1.561 lbs over placebo in the continuous dosing arm and 7.404 lbs over placebo in the intermittent dosing arm. Compared to placebo, continuous dosing with drisapersen increased mean total NSAA score from baseline by 1.60 points at week 25 and 2.5 points at week 49, while intermittent dosing with drisapersen increased mean total NSAA score from baseline by 1.75 points at week 25 and 2.29 points from baseline at week 49. Data were published on GSK's clinical trial registry. ...