Sarepta's shares rocket on positive results with eteplirsen in Duchenne muscular dystrophy

US RNA-based drug developer Sarepta Therapeutics (Nasdaq: SRPT) saw its shares leap 140% to $8.30 yesterday after the company, formerly known as AVI BioPharma, announced that treatment with its exon-skipping compound, eteplirsen, achieved a significant clinical benefit on the primary clinical outcome, the 6-minute walk test (6MWT), over a placebo/delayed treatment cohort in a Phase IIb trial in patients with Duchenne muscular dystrophy (DMD), a devastating progressive, degenerative, universally fatal neuromuscular disorder that affects about one in every 3,500 boys worldwide.

Eteplirsen administered once weekly at 50mg/kg over 36 weeks resulted in a 69.4 meter benefit compared to patients who received placebo for 24 weeks followed by 12 weeks of treatment with eteplirsen in the open-label extension. In the predefined prospective analysis of the study’s intent-to-treat (ITT) population on the primary clinical outcome measure, the change in 6MWT distance from baseline, eteplirsen-treated patients who received 50mg/kg of the drug weekly (n=4) demonstrated a decline of 8.7 meters in distance walked from baseline (mean=396.0 meters), while patients who received placebo/delayed-eteplirsen treatment for 36 weeks (n=4) showed a decline of 78.0 meters from baseline (mean=394.5 meters), for a statistically-significant treatment benefit of 69.4 meters over 36 weeks (p<0.019).

“Unprecedented” treatment effect, says principal investigator