Here's Why Sarepta Is Skyrocketing While BioMarin Is Falling

• Shares of Sarepta Therapeutics Inc SRPT gained more than 30 percent Friday morning, while shares of BioMarin Pharmaceutical Inc. BMRN lost more than 6 percent.
• The Wall Street Journal reported that BioMarin faces an FDA advisory committee next week to vote for approval or rejection of its drisapersen drug.
• The FDA's decision will "hold implications" for Sarepta as it has a rival drug in development.

Biotech investors are in store for a busy week ahead of the Thanksgiving holiday.

According to The Wall Street Journal, BioMarin Pharmaceutical, a biotech firm that develops and commercializes pharmaceuticals for rare and series diseases, will face an FDA advisory committee next week for drisapersen – an experimental drug for the treatment of Duchenne Muscular Dystrophy.

The FDA will vote to either approve or reject the drug next week but it has already released on Friday a preliminary review at the drug's viability on Friday.

According to The Street's Adam Feuerstein, the FDA's preliminary review of BioMarin's Duchenne drug was "harsh" and raised "serious questions" about its efficacy. The FDA also demonstrated concerns about the drug's safety.

Related Link: The Valeant News No One Is Talking About

Shares of BioMarin were trading lower by around 10 percent Friday morning but erased half of the losses and were trading lower by just over 4 percent after the market open.

"FDA drug reviews are known to be harsh, so the concerns raised about drisapersen do not necessarily spell doom for BioMarin at Tuesday's advisory panel meeting," Feuerstein cautioned in his report. "The experts on the panel will be weighing drisapersen's efficacy and safety data in the context of Duchenne being a fatal disease with no currently approved treatments. The panel might also be swayed by two hours of testimony from DMD patients, their families and advocates, most, if not all, will be urging the FDA to approve drisapersen."

Sarepta Therapeutics Soars In Contrast To BioMarin

Meanwhile, shares of Sarepta Therapeutics soared higher by more than 30 percent. Sarepta has a rival drug to BioMarin in development called eteplirsen, which will undergo its own FDA advisory panel review early next year.

WSJ opined that the outcome of BioMarin's meeting "will ripple out to stocks of seemingly unrelated companies" and that "investors don't know right now where the biotech billiard balls will end up."