 This multicenter, open-label, single-arm, extension study was designed to evaluate long-term tolerability, safety, and efficacy of cinacalcet. Subjects were enrolled immediately after they completed the parent study, 990120. All subjects began treatment with 30 mg cinacalcet twice daily BID, with dose adjustments made per protocol-specified guidelines. The study consisted of 2 consecutive phases that occurred in the following order: a dose-titration phase lasting 12 weeks and a maintenance phase lasting approximately 412 years. 