** Shares of biotech co ADCT.N fall ~25% to $8.23
** Co says co-founder Chris Martin has stepped down from his
role as chief executive officer urn:newsml:reuters.com:*:nASM000AVD
** Ameet Mallik has been appointed as new CEO
** Martin to serve on board and as chair of the Science and
Technology Committee
** All seven brokerages covering the stock rate it "buy" or
higher; their median PT is $34.50 - Refinitiv data
(Reporting by Mrinalika Roy in Bengaluru)
((mrinalika.roy@thomsonreuters.com; within U.S. +1 646 223
8780, outside U.S. +91 806749 8325;))