SGN-15 is being investigated for therapy of patients with prostate cancer in combination with the cytotoxic agent, Taxotere. The study is an open label, randomized phase II study for patients with documented hormone refractory prostate cancer who have not had any prior therapy with Taxotere or Novantrone. Both SGN-15 and Taxotere will be administered weekly over two 6 week courses separated by a 2 week rest period.