Roxadustat for Anemia in Patients with Chronic Kidney Disease

To the Editor: Chen et al. (Sept. 12 issue) 1 report that in their trial of roxadustat (FGCL-4592-808) in patients with chronic kidney disease who were not undergoing dialysis, roxadustat was more effective than placebo in correcting anemia. In this trial, the authors underestimated the effect of the drug on iron metabolism and instead focused on serum iron levels. The frequency of a transferrin saturation of less than 20% or a ferritin level of less than 100 μg per liter is important for the clinical diagnosis of iron deficiency, but those values were reported only at baseline. Given the data on . . .