Sarepta Shares Tank 44% On Negative FDA Outlook For Eteplirsen
On Thursday shares of Sarepta Therapeutics (SRPT) tanked by 44% after the FDA posted a negative briefing for the company's drug eteplirsen. The drug eteplirsen is being developed to treat patients with a rare muscle wasting disorder known as Duchenne Muscular Dystrophy -- DMD. The FDA noted that it was willing to review the drug, but was very reserved in the manner they spoke about Eteplirsen. This quote sheds some light:
"Although FDA is prepared to be flexible with respect to a devastating illness with no treatment options, we cannot approve drugs for which substantial evidence of effectiveness has not been established"
As observed above, the FDA has a major problem with the way the trial has established effectiveness. This refers to the fact that the trial the company ran only recruited 12 patients, which means that the patient population is too small. Another problem is that the trial was being done without a proper control -- or placebo. Instead the company would give one group of patients eteplirsen, while the other group took no drug for the first 25 weeks. After the first 25 weeks, the patients who took no drug were put on eteplirsen. The FDA has alluded that it is having a difficult time accepting the fact that the company has not run a trial with a placebo, and instead uses historical data to support evidence of efficacy.
Possibly even more concerning is the finding that the method used to determine efficacy is questionable and, when re-tested, gave substantially weaker results.
Sarepta will have the ability to go up against the FDA panel on April 25, and see if it can persuade panel members to vote for the recommendation for approval of eteplirsen. This panel review will just be a recommendation of "For" or "Against" approval. Ultimately, the FDA itself will decide whether or not the drug will be approved. The PDUFA date for eteplirsen has been set for May 26. With a negative sentiment from the FDA, Sarepta must hope that patient advocates will convince the panel to approve the drug. If Sarepta comes empty-handed on Monday then it will not bode well for the PDUFA review by the FDA itself. The hope of DMD patients, and Sarepta investors, now lie in the hands of the FDA.