BLT.AX says CEO and Managing Director Dr Peter French Resigned, page-70

Rubbish, this is primarily a safety trial. There does not need to be any evidence of HCV knockdown whatsoever for it to continue. Knockdown may well not occur until the highest dose, if at all. So long as there are no life-threatening side effects from the drug, there is no reason why it cannot continue and no reason to suggest that they know whether the drug is working, and withholding information. You forget that the trial is being run by a third party. There is no way that the 4th cohort has reliable results as of yet.

Peter French has stepped down because he and the board realise that his continuing in the role of MD/CEO is hurting the share price. He is probably happy to go so that his name is not dragged through the mud every day by disgruntled shareholders and people like Dr. KSS and Dirk who were offended at not been offered a position to help run the trial or head up their lab. The company is at a stage where they need a salesman with a proven track record of landing deals with BigPharma, not a geeky scientist type whose reputation has been absolutely decimated by individuals with narcissistic personality disorders.