A Study Evaluating the Safety and Efficacy of RDX013 for the Treatment of Hyperkalemia

Inclusion Criteria: 1. Males or females aged 18 to 85 years, inclusive 2. Serum potassium value 5.1 to \<6.5 mmol/L 3. Chronic kidney disease with eGFR ≥20 to \<60 mL/min/1.73m2 4. Able to understand and comply with the protocol 5. Willing and able to sign informed consent Exclusion Criteria: 1. Pseudo-hyperkalemia signs and symptoms 2. Treatment with potassium-lowering drugs within 7 days prior to enrollment/randomization 3. Treatment with glucocorticoids 4. Uncontrolled Type 2 diabetes, defined as most recent historical HbA1c \> 10%, or hospitalization to treat hyper- or hypo-glycemia in the past 3 months 5. Diabetic ketoacidosis 6. Severe heart failure, defined as NYHA (New York Heart Association) Class IV or hospitalization to treat heart failure in previous 3 months 7. History of bowel obstruction, severe gastrointestinal disorders, or major gastrointestinal surgery (e.g., large bowel resection) 8. Females who are pregnant, lactating, or not willing to use appropriate contraception