During a 4-week washout period, participants stopped taking cinacalcet or other vitamin D receptor activators (VDRAs). (Participants who were naive to cinacalcet or VDRAs did not have to wash out). At randomization, participants entered a 28-week open-label treatment period, during which they received either cinacalcet or paricalcitol. Participants who were assigned to receive paricalcitol were dosed according to the approved label in their respective geographic regions (i.e., IV at sites in the US and Russia and oral at sites in Europe). Supplemental cinacalcet was administered to participants in the paricalcitol arms who developed hypercalcemia (defined as \>= 10.5 mg/dL). The evaluation period was from Weeks 21 to 28.
