Inclusion Criteria:  Chinese subjects at least 18 years of age. Chronic Kidney Disease (CKD) stage 3 and 4. Serum potassium higher than 5.0 and lower than 6.5 mEq/L at Day 0/baseline. Subjects on any stable dose of at least 1 RAASi medication for at least 28 days before Day 0/baseline. If on antihypertensive medication, have a stable dose for 28 days before Day 0/baseline. Women of childbearing potential must agree to continue using contraception throughout the study and for 4 weeks after study completion.  Exclusion Criteria:  Any level of hyperkalemia at Day 0/baseline that, in the opinion of the Investigator, requires emergency intervention. Type 1 diabetes or Type 2 diabetes mellitus with haemoglobin (Hb) A1c higher than 10.0% at Day 0/baseline. History of acute renal insufficiency in the past 3 months prior to the beginning of the study. Diseases affecting the hearth muscle and heart's ability to pump blood around the body Major surgery including thoracic and cardiac within 3 months prior to the beginning of the study or anticipated need during study participation. Heart or kidney transplant recipient or anticipated need for transplant during study participation Diagnosis or treatment of a malignancy in the past 2 years before Day 0/baseline. Use of potassium supplements, bicarbonate or baking soda in the last 7 days prior to Day 0/baseline. Pregnant women or breastfeeding.