The Street's Adam Feuerstein Breaks Down Sarepta's 40% Plunge

Shares of

plunged more than 40 percent on Thursday after the U.S. Food and Drug Administration (FDA) released

The Street's biotech expert Adam Feuerstein

, the FDA's update still marks a "negative clinical review" of the drug. Sarepta submitted to the FDA new data to support its drug candidate in January in hopes of changing the FDA's negative leaning stance. As noted by Feuerstein, the FDA "did not change its opinion" in its Thursday update. "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," the FDA said in its document. Feuerstein pointed out that the FDA's commentary on Thursday is identical to its view which was communicated in January. The company will be given an opportunity to rebut the FDA's negative stance on April 25. "If Sarepta lacks clinical data to make a convincing case for eteplirsen's approval, it will fall back on the argument that eteplirsen is safe, therefore DMD patients and their families should be allowed to try the drug while an ongoing, confirmatory phase III study moves towards completion," Feuerstein wrote. "Two and half hours have been set aside on Monday for an open public hearing where DMD patients and their families are expected to urge the panel experts to recommend eteplirsen's approval. The testimony is likely to be emotional and may counteract the FDA's negative tone."