Pharmacodynamic & Safety of Patiromer in Children & Adolescents (2-<18 Yrs) With Chronic Kidney Disease and Hyperkalemia

Up to 54 subjects, 2 - \< 18 years of age with CKD (estimated glomerular filtration rate \[eGFR\] \< 90 mL/min/1.73 m2 ) and hyperkalemia (two potassium measurements of 5.1 to \< 6.5 mEq/L performed on separate days) will be enrolled in this open-label, multiple-dose, Phase 2 study. The study will include two treatment phases: Pharmacodynamic (PD; drug effect on potassium) / Dose Finding Phase consisting of the initial 14-day dose finding period followed by an up to 5.5-month Long-Term Treatment Phase for a total study participation duration for individual subjects of up to 6.5 months (includes a 2 week follow up period).