A Phase 4 Study to Determine Dosing of Hectorol® Capsules When Converting From Zemplar® Injection

Inclusion Criteria: * The subject must be receiving hemodialysis three times per week for a minimum of six months. * The subject must have been receiving Zemplar Injection for a minimum of 3 months. The subject must have been on a stable dose regimen, three times per week administration for a minimum of four weeks. * The central laboratory assessment must be within the following ranges: serum iPTH between 150-600 pg/mL, inclusive; corrected calcium \< 10.0 mg/dL; phosphorus \< 7.0 mg/dL. Exclusion Criteria: * In the opinion of the Investigator, the subject currently has poorly controlled diabetes mellitus, poorly controlled hypertension, active vasculitis, HIV infection, or any other clinically significant, unstable medical condition. * Abnormal liver function as measured by ALT/AST greater than two times the upper limit of normal (ULN). * The subject currently has malabsorption, severe chronic diarrhea, or ileostomy. * Any evidence of active malignancy except for basal cell carcinoma of the skin. A history of malignancy is not an exclusion.