Within a cohort, the second dose will only be given if safety and tolerability of the first dose is acceptable. This assessment will be based on evaluation of data up until Day 7 by the Independent Safety Committee (ISC) as per written guidance. The first dose of each cohort will be administered during an inpatient stay. Escalation to the next dose level will be dependent on an acceptable safety profile of the first dose at the previous dose level, based on evaluation of safety data by an Independent Safety Committee (ISC). The decision to administer the second dose at the higher level will also require review of the safety and tolerability of the second dose at the lower level.