This is a multicenter, single-arm, extension study in which adults with secondary hyperparathyroidism currently receiving hemodialysis and previously treated in Amgen studies 20120231 (NCT01785875), 20120334 (NCT01576146), or 20120360 (NCT01896232) will continue to be treated with etelcalcetide until approximately 2.5 years after the first participant was enrolled.