Eteplirsen: Phase IIb data

The double-blind, U.S. Phase IIb Study 4658-US-201 trial in 12 patients aged 7-13 with DMD showed that once-weekly 30 mg/kg IV eteplirsen met the primary endpoint of increasing dystrophin-positive muscle fibers as a percentage of normal from baseline to week 24 vs. placebo (22.5% vs. 0%, p<=0.002). The once-weekly 50 mg/kg dose of eteplirsen did not significantly increase dystrophin-positive muscle fibers as a percentage of normal from baseline at week 12 (0.79%). AVI said the data suggest that a longer duration of dosing is required before "meaningful levels" of dystrophin are produced. Additionally, the company said that there were no significant improvements from baseline on any clinical outcomes, including the 6-minute walk test (6MWT), vs. placebo at week 24. All patients receiving eteplirsen or placebo remained stable with no decline in clinical outcomes at week 24, which the company said suggests that a longer period of observation will be required to demonstrate clinical effects of eteplirsen vs. a placebo control. ...