DUBLIN – Motif Bio plc's stock collapsed during early trading in London Tuesday on news that the FDA issued a complete response letter (CRL) requesting more liver toxicity data in its NDA for iclaprim, an antibiotic in development to treat acute bacterial skin and skin structure infections (ABSSSI) caused by gram-positive pathogens. Shares in the company (LONDON:MTFB; NASDAQ:MTFB) fell by as much as 88 percent during early trading on AIM before ending the day at 10.8 pence (US$0.14), down 73 percent. The stock's ADRs took a similar tumble on Wall Street (NASDAQ:MTFB), where they closed at $2.72.