Pilot Study Evaluating Doxercalciferol Replacement Therapy in Kidney Transplant Recipients

People with kidney transplants often develop bone disease. One reason for bone disease may be overactivity of a gland in the neck called the parathyroid gland. Overactivity of the parathyroid gland may be caused by lack of Vitamin D in the body. It has recently been discovered that many patients with kidney transplants have low Vitamin D levels.

25-OH Vitamin D3 is now recommended to treat kidney transplant patients with low vitamin D levels but it may not be enough to treat the parathyroid problems and bone disease. Doxercalciferol is a form of Vitamin D that has been used to treat bone disease and parathyroid problems in dialysis patients but has not yet been studied in patients with kidney transplants. We are interested in seeing whether doxercalciferol given together with 25-OH Vitamin D3 will be a better treatment for the overactive parathyroid gland and bone disease than 25-OH Vitamin D3 alone in patients with kidney transplants.

Inclusion criteria

• Adults of both genders between the ages of 18 and 65.
• Kidney transplant at least 1 year prior to enrollment
• Creatinine value of <2.5 mg/dl with no excursion >0.5 within the past 3 months
• Proteinuria of 500 mg/24 hours or a protein/creatinine ratio of 0.5 or greater
• Hypovitaminosis D, as defined by a 25-OH Vitamin D value of <25 ng/ml
• Intact PTH value between 150 and 600 pg/ml

Exclusion criteria

• History of parathyroidectomy
• History of prior intolerance to vitamin D therapy (not including hypercalcemia)
• History of biopsy proven acute rejection over the 3 months preceding enrollment
• Recent (over the past month) addition of an ACE inhibitor or Angiotensin -
• Receptor Blocking agent - patients who have been on a stable dose are acceptable
• Current use of active Vitamin D supplement (patients in whom therapy has been discontinued more than 1 month prior to enrollment are acceptable)
• Postmenopausal woman or women receiving hormone replacement therapy