 This is a two part Phase IIb, open-label, non-randomized and multi-center, dose escalation study with a 33 design Part 1 and an expansion cohort at the Maximum Tolerated Dose MTDRecommended Phase 2 Dose RP2D Part 2. If MTD is not reached in Part 1, RP2D will be determined after completion of Part 1 considering safety and tolerability, also beyond the dose limiting toxicity DLT period, pharmacokinetic PK and pharmacodynamic PD results. 