In many ways, the FDA's eteplirsen review posted Friday is more negative than the one issued in January. The FDA rebuts, sometimes in sharply critical ways, Sarepta's claims the agency's original review was flawed. Most notably, the FDA is deeply skeptical of Sarepta's attempt to use a data from a retrospective, historical control study of DMD patients to demonstrate the efficacy of eteplirsen.
The use of "historical" data as the control in a clinical trial always gets researchers' hackles up. Not just at FDA, since one can find some historical data which makes a sponsor's drug look like a miracle. There's good reason to require Phase III, approval, studies to be double-blind, placebo (or, better yet, standard of care) controlled. Wasting money on pointless drugs is, well, a waste.