5. Has for ≥ 3 months prior to Screening, chronic kidney disease (CKD) stage 4 (defined as estimated glomerular filtration rate (eGFR) <30 ml/min/1.73 m^2 by Modification of Diet in Renal Disease (MDRD) formula), or CKD stage 5 on dialysis (ie eGFR <15 ml/min/1.73 m^2 by MDRD formula).