A Study of AST-120 for Evaluating Prevention of Progression In Chronic Kidney Disease (EPPIC-1)

Inclusion Criteria: * Age 18 years or older * Moderate to severe CKD, not anticipated to require dialysis or renal transplant within the next 6 months * Patient survival expected to be no less than one year * Serum creatinine in men \>= 2.0 mg/dL (\>= 177 µmol/L) and \<= 5.0 mg/dL (\<= 442 µmol/L), and in women \>= 1.5 mg/dL (\>= 133 µmol/L) and \<= 5.0 mg/dL (\<= 442 µmol/L) at Screening * Urinary total protein to urinary total creatinine ratio must be \>= 0.5 on a spot void at Screening * Blood pressure \<= 160/90 mmHg at both Screening and Baseline. In addition, blood pressure, if measured, must have been stable in hypertensive patients over the 3 months prior to Screening, with no more than 1 blood pressure reading \> 160/90 mmHg * In patients being treated for hypertension, they should be on a stable anti-hypertensive regimen Exclusion Criteria: * Obstructive or reversible cause of kidney disease * Nephrotic syndrome defined as a ratio of urinary total protein to urinary creatinine of \> 6.0 as measured on a spot void * Adult polycystic kidney disease * History of previous kidney transplant * History of recent (within the past 6 months) accelerated or malignant hypertension * Uncontrolled arrhythmia or severe cardiac disease within the past 6 months * History of malabsorption, inflammatory bowel disease, hiatal hernia, active peptic ulcer, or severe GI dysmotility, not attributable to the use of a phosphate binder * Received any investigational agent or participated in a clinical study within the previous 3 months * Presence of any significant medical condition that might create an undue risk with study participation, or significantly confound the collection of safety and efficacy data in this study