• The proportion of subjects achieving at least a 15% reduction in the last on-treatment UACR levels from baseline; the change from baseline to the last on-treatment measurement in albumin determined from 24-hour urine collections. [ Time Frame: after 24 weeks of treatment ] [ Designated as safety issue: No ]
• The change from baseline to the last on-treatment measurement in albumin determined from 24-hour urine collections [ Time Frame: after 24 weeks of treatment ] [ Designated as safety issue: No ]

• The proportion of subjects achieving at least a 15% reduction in the last on-treatment UACR levels from baseline
• The change from baseline to the last on-treatment measurement in albumin determined from 24-hour urine collections

The study objective is to evaluate the effect of paricalcitol capsules on albuminuria reduction in Chronic Kidney Disease (CKD) subjects with Type 2 diabetic nephropathy receiving optimal ACEi and/or ARB therapy

• Diabetic Nephropathy
• Chronic Kidney Disease Stages 3 and 4

• Drug: Zemplar (paricalcitol ) capsules
• Drug: Zemplar (paricalcitol) capsules
• Drug: Placebo

• Active Comparator: One paricalcitol 1 mcg capsule and one matching placebo capsule per dose
• Active Comparator: Two paricalcitol 1 mcg capsules per dose
• Placebo Comparator: Two placebo capsules per dose

Inclusion Criteria:

• Male or female subjects >= 20 years old.
• Subject has Type 2 Diabetes Mellitus and has been treated with at least one anti-hyperglycemic medication within the 12 months prior to the Screening Phase
• Subject has been receiving a stable dose (i.e., same type and regimen) of ACEi and/or ARB for at least three months prior to the Screening Phase. However, subject may have switched to different brands but at equivalent doses during the three months prior to the Screening Phase.
• Subject is not expected to begin dialysis for at least 6 months.
• If female, subject is not breast feeding or is not pregnant.

• For entry into the Treatment Phase the subject must satisfy the following criteria based on the Screening laboratory values:

  • Estimated GFR between 15-90 mL/min/1.73m2 by simplified MDRD formula
  • UACR between 100 and 3000 mg/g as determined by the mean of the three first morning void urine specimens obtained within one week of each other
  • Corrected serum calcium level <= 9.8 mg/dL
  • iPTH value between 35-500 pg/mL
  • HbA1c <= 12%
  • Serum albumin > 3.0 g/dL
  • Negative urine pregnancy test for female subjects

Exclusion Criteria:

• Subject has previously been on prescription-based vitamin D therapy within the six months prior to the Screening Phase.
• Subject has a history of an allergic reaction or significant sensitivity to paricalcitol or to drugs similar to the study drug.
• Subject has primary glomerulonephritis or secondary nephritis in addition to diabetic nephropathy.
• Subject has had acute renal failure within 12 weeks of the Screening Phase.
• Subject has chronic gastrointestinal disease.
• Subject has secondary hypertension.
• Subject has poorly controlled hypertension.
• Subject has a history of kidney stones.
• Subject has a history of drug or alcohol abuse within six months prior to the Screening Phase.
• Subject has evidence of poor compliance with diet or medication.
• Subject has received any investigational drug within 30 days prior to study drug administration.
• Subject is taking calcitonin, bisphosphonates, cinacalcet, glucocorticoids (except topical glucocorticoids), or other drugs that may affect calcium or bone metabolism, other than calcium containing phosphate binder or female subjects on stable (same dose and product for three months) estrogen and/or progestin therapy.
• For any reason, subject is considered by the Investigator to be an unsuitable candidate to receive paricalcitol capsules or is put at risk by study procedures.
• Subject is known to be HIV positive.
• Use of known inhibitors or inducers of cytochrome P450 3A (CYP3A) within two weeks prior to study drug administration.