 The study is divided into two parts. Part A is an open-label, non-randomized, non-placebo-controlled dose escalation study with a 28-day treatment phase and 14-day follow-up phase with five cohorts . Part B is a randomized, placebo-controlled, confirmatory 2x2 crossover cohort with a 28 day washout between periods, and a 28-day follow-up phase. 