TD Cowen downgrades Sarepta Therapeutics to 'hold'

** TD Cowen downgrades its rating on gene therapy developer Sarepta Therapeutics SRPT.O to "hold" from "buy"

** Brokerage says there is an increased probability of FDA withdrawal of Elevidys for non-ambulatory and even ambulatory patients, if SRPT continues to lose support from the Duchenne Muscular Dystrophy (DMD) community

** On Sunday, Sarepta announced a second death of a patient from acute liver failure after receiving its gene therapy Elevidys

** Elevidys is a one-time gene therapy that delivers a micro-dystrophin gene to muscle cells, aiming to treat the root cause of DMD, which causes progressive muscle deterioration

** Brokerage cuts PT to $24 from $62; new PT still represents an 11.3% upside to stock's last close

** As of last close, stock down ~82.3% YTD