1. Treatment with androgen receptor antagonists (enzalutamide, bicalutamide, flutamide, nilutamide), 5-alpha reductase inhibitors (finasteride, dutasteride), estrogens, or chemotherapy within 4 weeks of enrollment (Day 1 visit) or plans to initiate treatment with any of these drugs during the study. Ongoing therapy with biphosphonates or Rank Ligand inhibitors are acceptable.