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 4½ years.

Inclusion Criteria:

• Successfully completed the parent study 990120
• Agreed to use highly effective (in the opinion of the principal investigator) contraceptive measures throughout the study
• Were able to comprehend and were willing to give written informed consent for participation in the study

Exclusion Criteria:

• Pregnant or breast-feeding
• Had a psychiatric disorder that interfered with the understanding and giving of informed consent or compliance with protocol requirements
• Had any other condition that reduced the chance of obtaining data (eg, known poor compliance)
• Participating in another investigational study at the time of study entry
• Had any unstable medical condition, defined as having been hospitalized within 28 days before day 1, or otherwise unstable in the judgment of the investigator