H.C. Wainwright analyst Debjit Chattopadhyay raised his price target for Sarepta Therapeutics (SRPT) to $260 from $160 after the FDA reversed course and approved Vyondys 53.

The analyst expects the stock to "churn higher into 2021."

Today's move "could be just a harbinger," Chattopadhyay tells investors in a research note. Sarepta in premarket trading is up 30%, or $30.55, to $131.02. Given the FDA's course correction, the follow-on approval of casimersen now becomes a high probability outcome, and translates into a nearly $700M topline for Sarepta during 2021, prior to any material gene therapy revenue, says Chattopadhyay. 

The analyst keeps a Buy rating on Sarepta.