Sarepta tanks despite positive data on eteplirsen in Duchenne MD

US RNA-based drug developer Sarepta Therapeutics (Nasdaq: SRPT) saw its shares plunge, despite the company releasing positive new mid-stage data on its investigational drug eteplirsen yesterday.

The stock was down about 21% to $20.46 mid-morning amid heavy selling in the broader market, noted CNBC News. One analyst said the data may call into question how well the drug works over longer periods. For companies developing drugs for rare diseases, data in just a handful of patients can have enormous clinical implications and influence millions of dollars in market value, commented SNBC.

Sarepta announced data through Week 144 from Study 202, a Phase IIb open-label extension trial of eteplirsen in patients with Duchenne muscular dystrophy (DMD). After nearly three years of follow up, results on the 6-minute walk test (6MWT) showed a decline in walking ability at a rate slower than would be expected based on available DMD natural history data.