** Shares of gene therapy makers rise premarket after the departure of Vinay Prasad, the FDA's chief medical and science officer

** Sarepta Therapeutics SRPT.O up 10.2%, Capricor CAPR.O up 20%, U.S.-listed shares of Crispr Therapeutics CRSP.O up 1.3% premarket

** Prasad has left the health regulator, the U.S. Department of Health and Human Services, which oversees the FDA, said on Tuesday, confirming an earlier news report

** Prasad's departure comes after a number of controversial decisions by the FDA regarding a gene therapy drug for the treatment of Duchenne muscular dystrophy manufactured by SRPT

** BMO Capital Markets says "We think that Prasad's departure is a big positive for biotech in general and cell and gene therapies in particular, given that Prasad's appointment was perceived as a 'worst-case scenario' by investors"

** Drug developer Replimune Group's REPL.O shares also up 56% at $5.85 premarket

** In July, the FDA also declined to approve REPL's experimental skin cancer drug, RP1 for advanced melanoma and CAPR's cell therapy for a heart condition

** Up to last close, REPL down 69%, CAPR down 51.2%, SRPT down 87% while CRSP up ~50% YTD

(Reporting by Siddhi Mahatole)

((siddhi.mahatole@thomsonreuters.com))