This is a randomized, double-blind, placebo-controlled study of the vitamin D analog 2-methylene-19-nor-20S-1α,25-dihydroxyvitamin D3 (DP001) in patients with end-stage renal disease (ESRD). The effect of 12 weeks of oral administration of DP001 on serum parathyroid hormone (PTH) levels will be evaluated in ESRD patients who have secondary hyperparathyroidism.