In a pooled analysis of placebo controlled studies (n=2,313) for 26 weeks, a 5.1% mean change in serum phosphate was observed among the highest dose of 300mg compared to placebo. In another 26-week analysis (n= 269) of renal impairment patients (eGFR greater than or equal to 30 and < 50 ml/min/1.73 m(2)), serum phosphate increased 7.8% above baseline and 1,25-hydroxyvitamin D decreased by 8.1% from baseline 44. Interestingly, the most acute changes in serum phosphate (0.5 mg/dL mean change from baseline) was reported within three weeks of study initiation.