The causes of this mostly reversible nonprogressive increase in serum creatinine in patients treated with deferasirox are still controversial. It has been hypothesized that the underlying mechanism is related not to a nephrotoxic effect of the drug itself but to overchelation leading to a relative depletion of iron and reduction in GFR.4 This hypothesis stems from observations of a similarly high rate of serum creatinine increase in the deferoxamine group (14% in patients with β-thalassemia major and 22% in those with sickle cell disease) during the randomized trials,27,30 and the fact that increases in serum creatinine are more common in patients who showed dramatic decreases in liver iron concentration and serum ferritin level or those with lower transfusion rate and baseline iron indices.27