 A screening examination will be performed within 14 days prior to dosing. Eligible subjects will receive 4 doses of PAT-SM6 cycle 1: Day 1 and Day 3, cycle 2: Day 8 and Day 10. Subjects will be hospitalised for at least 48 hours after each dose administration i.e. from Day 1 to Day 5 in cycle 1 and from Day 8 to Day 12 in cycle 2. During hospitalisation subjects will be under constant surveillance. Subjects will return for ambulatory visits on Days 15, 22, 29 and 36 for safety, pharmacokinetic PK and pharmacodynamic PD assessments. 