SRPT PUT premiums are very high .... with the stock now at $27.45, the May $27 PUTs are offered at $6.70 ... so the stock would have to drop to $20.75 by expiration just to break even. To realize a 100% gain it has to drop all the way down to $14.05, which seems improbable even if they do have to conduct a full new trial.
SRPT - I'm surprised the FDA doesn't offer some sort of limited qualified approval in a case like this .... let the patient (or parents) decide if they'll accept the risk of taking the drug - without liability to the company or FDA.