Sample size
The target population was 40 patients. For the primary endpoint of change in serum phosphorus levels from baseline at week 8, assuming a mean change in serum phosphorus levels of 1.0 mg/dL with a standard deviation (SD) of 2.0 mg/dL, this sample size would allow for a 95% confidence interval (CI) with a precision of − 1.6 to − 0.4 mg/dL.