Sarepta Says Eteplirsen Shows Sustained Benefit on Walking Test Through 74 Weeks in Phase IIb Study

Sarepta Therapeutics, Inc. SRPT, a developer of innovative RNA-based therapeutics, today announced updated data from Study 202, a Phase IIb open-label extension study of eteplirsen in patients with Duchenne muscular dystrophy (DMD). Results at 74 weeks showed a continued stabilization of walking ability in eteplirsen-treated patients evaluable on the 6-minute walk test (6MWT). As previously reported, Study 202 met its primary endpoint of increased novel dystrophin as assessed by muscle biopsy at week 48 and is now in the long-term extension phase in which patients continue to be followed for safety and clinical outcomes. Eteplirsen is Sarepta's lead exon-skipping compound in development for the treatment of patients with DMD who have a genotype amenable to skipping of exon 51. After 74 weeks, patients in the 30 mg/kg and 50 mg/kg dose cohorts who were able to perform the 6MWT (modified Intent-to-Treat or mITT population; n=6) showed a statistically significant treatment benefit of 65.2 meters (p d 0.004) when compared to the placebo/delayed-treatment cohort (n=4). The eteplirsen-treated patients in the mITT population demonstrated less than a 5 percent decline (13.4 meters) from baseline in walking ability. After experiencing a substantial decline earlier in the study, the placebo/delayed-treatment cohort also demonstrated stabilization in walking ability from week 36 through 74, the period in which meaningful levels of dystrophin were likely produced, with a less than 10 meter decline over this timeframe. "We are encouraged to see a continued stabilization of walking ability in patients treated with eteplirsen for nearly one and a half years," said Chris Garabedian, president and chief executive officer of Sarepta Therapeutics. "These data are particularly compelling when viewed in the context of published natural history studies, which showed substantial declines on the 6-minute walk test over this timeframe in a similar ambulatory DMD population. These results con tinue to support the potential of eteplirsen to be a major advance in the treatment of DMD in altering the course of this progressive and irreversible disease." Through 74 weeks, eteplirsen was well tolerated and there were no clinically significant treatment-related adverse events, serious adverse events, hospitalizations or discontinuations. As previously reported at 62 weeks, one patient had a transient elevation of urine protein on a laboratory urine dipstick test, which resolved and resulted in no clinical symptoms. The patient continued treatment without interruption and remained free of proteinuria through week 74. Across both the eteplirsen (mITT) and placebo/delayed-treatment cohorts, there is evidence of continued stabilization on clinical laboratory tests, echocardiogram, pulmonary function tests and muscle strength.