 Weight-dependently, pharmacokinetic PK and pharmacodynamic PD data are collected once in a full PKPD day over 12, respectively 6 hours, and single PKPD samples at each Dose Titration Visit and each bi-weekly Study Control Visit until the Last Visit after 8 weeks of treatment. Blood pressure and renal monitoring is performed at each visit before deciding on the dose level for the next treatment period. 