- Have the following central laboratory measurements: 1. If not on a phosphate binder, a serum phosphorus measurement ≥ 5.5 mg/dL (1.76 mmol/L) at Screening (Visit1). 2. If taking a phosphate binder(s) at screening, a serum phosphorus measurement ≥ 5.5 mg/dL (1.76 mmol/L) after the two-week washout period at Visit 1a (Day 0).