BUZZ-Valeant Pharmaceuticals: Set for 3rd straight day of gains
** Canadian drugmaker's U.S.-listed shares up 3.5 pct at $33.01 premarket, set to add to 17 pct gain since Friday close
** Stock on track for best week in 2016
** Valeant said on Monday its CEO will leave and billionaire investor William Ackman will join the board
** Up to Tuesday's close, stock had fallen 88 pct since touching record high of $263.81 in early August
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