The Effect of Paricalcitol Capsules on Reducing Albuminuria in Patients With Type 2 Diabetic Nephropathy Being Treated With Renin-angiotensin System Inhibitors

Inclusion criteria

• Male or female participant >= 20 years old.
• Participant 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
• Participant 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, participant may have switched to different brands but at equivalent doses during the three months prior to the Screening Phase.
• Participant is not expected to begin dialysis for at least 6 months.
• If female, participant is not breast feeding or is not pregnant.
• For entry into the Treatment Phase, the participant must satisfy the following criteria based on the Screening laboratory values:

• Estimated glomerular filtration rate (GFR) between 15-90 mL/min/1.73m2 by simplified Modification in Diet in Renal Disease (MDRD) formula
• Urinary albumin to creatinine ratio (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
• intact parathyroid hormone (iPTH) value between 35-500 pg/mL
• Glycosylated hemoglobin A1c (HbA1c) <= 12%
• Serum albumin > 3.0 g/dL
• Negative urine pregnancy test for female participants

Exclusion criteria

• Participant has previously been on prescription-based vitamin D therapy within the six months prior to the Screening Phase.
• Participant has a history of an allergic reaction or significant sensitivity to paricalcitol or to drugs similar to the study drug.
• Participant has primary glomerulonephritis or secondary nephritis in addition to diabetic nephropathy.
• Participant has had acute renal failure within 12 weeks of the Screening Phase, defined as an acute rise (of >= 0.5 mg/dL) in serum creatinine to > 4 mg/dL.
• Participant has chronic gastrointestinal disease.
• Participant has secondary hypertension.
• Participant has poorly controlled hypertension.
• Participant has a history of kidney stones.
• Participant has a history of drug or alcohol abuse within six months prior to the Screening Phase.
• Participant has evidence of poor compliance with diet or medication.
• Participant has received any investigational drug within 30 days prior to study drug administration.
• Participant 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 participants on stable (same dose and product for three months) estrogen and/or progestin therapy.
• For any reason, participant is considered by the Investigator to be an unsuitable candidate to receive paricalcitol capsules or is put at risk by study procedures.
• Participant is known to be human immunodeficiency virus (HIV) positive.
• Participant has used known inhibitors or inducers of cytochrome P450 3A (CYP3A) within two weeks prior to study drug administration.