In ESA‐untreated patients with NDD‐CKD, vadadustat increased endogenous EPO production, with mean serum EPO concentrations between 16 and 21 mIU/mL, which is at, or slightly above, the upper limit of the range for healthy individuals (3.3–16.6 mIU/mL) and consistent with earlier results with vadadustat.33, 34. This evidence concerns the gene EPO and chronic kidney disease.