FGF23 and kidney failure: Given the body of observational and supportive experimental evidence linking FGF23 and adverse outcomes, and the recent development of neutralizing anti-FGF23 antibodies51 and blocking antibodies against FGF receptor 4 that mediates the pathologic effects of FGF23,11,13 there is a growing interest to test whether interventions targeting FGF23 improve clinical outcomes in patients with kidney failure.