FGF23 and secondary hyperparathyroidism: We previously demonstrated, in a randomized controlled trial of hemodialysis patients with secondary hyperparathyroidism that treatment with the calcimimetic etelcalcetide (ETEL) could inhibit the progression of LV mass index compared to active vitamin D therapy with alfacalcidol (ALFA) and that this was associated with the drug-induced suppression of fibroblast growth factor 23 (FGF23) [9].