Serepta Shares Fall Following Release of Clinical Trial Data
Shares for Serepta plunged on Thursday after clinical trial data suggested an accelerated decline in walking ability for trial patients being treated with the company’s experimental DMD drug, eteplirsen.
Details of the Eteplirsen Clinical Trial
According to Reuters, Serepta Therapeutics Inc’s muscle wasting disorder drug, eteplirsen, has caused an accelerated decline in trial patients’ walking ability after three years of using the drug.
Eteplirsen is used to treat Duchenne muscular dystrophy, DMD, which is a degenerative disorder that inhibits muscle movement; DMD affects one in every 3,600 newborn males. Since there is no known cure, DMD patients generally die before age 30.
The drug’s trial includes 12 patients who were given the drug or a placebo as researchers evaluated the production of dystrophin after 25 weeks.
After 144 weeks, the patients treated with the drug continuously from the beginning had a reported loss of up to 32.2 meters from baseline walking ability, which is measured by a six-minute walk test. Patients who began on the placebo and then switched to etepliersen suffered an even larger decline of 107.4 meters.
Eteplirsen’s trial results sent the company’s shares down 28%, but analysts state that the company is still on track for approval of the drug for the end of the year.
Shares for Similar Drugs Drop
The results of the eteplirsen study caused a decline in the rival drug, Prosensa Holding NV’s Drisapersen, as well, since both skip a faulty section of the gene in order to produce dystrophin. Drisapersen shares declined 5 percent.
Debjit Chattopadhyay, an analyst for Roth Capital Partners, wrote, “The reason for the sell-off in the stock is related to the acceleration in the rate of decline over the last six months, which can be taken as waning in eteplirsen efficacy”.
The US Food and Drug Administration are suggesting an alternate plan for the approval of eteplirsen though since Sarepta’s marking application was said to be premature in 2013. The FDA stated that safety and efficacy data from studies that did not use placebo groups could further support the company’s marketing application.
However, Brian Kelin, an analyst at Stifel & Co, stated that the drug’s ability to show an improvement over the placebo group still qualifies the drug as effective because “If, after 144 weeks, you're concerned about disease progression, it's not a problem that you want… But it's better than no efficacy at all”. Sarepta shares declined 12% to $22.55 according to the Nasdaq on July 10th.