Sarepta Therapeutics, Inc. (SRPT) reported results through week 144 from a phase IIb study (Study 202: a long-term open-label extension study) on its lead candidate, eteplirsen, being developed for the treatment of Duchenne muscular dystrophy (DMD).
Sarepta’s shares tumbled 12.9% following the news. The study’s 144 week data was comparatively weaker than the 120 week data reported in Jan 2014.
Results from the study through 144 weeks revealed that patients under eteplirsen cohorts (30 mg/kg and 50 mg/kg) being able to perform a 6-minute walk test experienced a decline of 33.2 meters from baseline in walking ability. However, a statistically significant benefit of 75.1 meters was observed in modified Intent-to-Treat (mITT) population (n=6) compared with the placebo/delayed-treatment cohort (n=4), who started treatment with eteplirsen at week 25 after 24 weeks of placebo treatment.
Meanwhile, Sarepta’s previously reported 120-week data showed that patients under eteplirsen cohorts experienced a decline of 13.9 meters from baseline in walking ability as against a statistically significant benefit of 64.9 meters in mITT population compared with the placebo/delayed-treatment cohort, who started treatment with eteplirsen at week 25 after 24 weeks of placebo therapy.
Sarepta shares had soared over 39% earlier this year after it announced that it would submit a New Drug Application (:NDA) to the FDA for eteplirsen in the DMD indication by year end. Sarepta’s decision on the filing of regulatory application for eteplirsen was based on a guidance letter from the FDA. In Nov 2013, the FDA had stated that the NDA filing of eteplirsen would be premature at that time. The company met with the FDA several times before receiving the guidance letter.
The company maintained its stance that it will be filling for eteplirsen by year end. However, we remain concerned about the relatively weaker results at week 144 compared to that of week 120. Sarepta shares may drop further if any other disappointing news on its lead candidate emerges.
Sarepta Therapeutics currently carries a Zacks Rank #3 (Hold). Some better-ranked stocks include Actelion Ltd. (ALIOF), The Medicines Company (MDCO) and Synergy Pharmaceuticals, Inc. (SGYP). All three stocks carry a Zacks Rank #1 (Strong Buy).