** New York-listed shares of troubled Canadian drugmaker down 10.9 pct at $25.70, set to open at two-week low
** Posts lower-than-expected Q1 profit, hurt by challenges in dermatology unit (bit.ly/1Zu6unQ)
** Slashes FY revenue and adjusted profit guidance for second time this year
** Newly appointed CEO Joseph Papa says majority of business "performing according to expectations"
** Company, under scrutiny for its business and accounting practices, and under pressure to file its quarterly report on time, says it will file results in "timely manner" going forward
** Valeant's U.S.-listed stock down nearly 72 pct YTD through Monday and down 89 pct from August record high of $263.81