Tivozanib is an anti-angiogenesis medicine that fights different types of cancer by blocking the blood supply to the tumor, so that the tumor does not receive the nutrients it needs to grow. The main goal of this study is to determine whether the combination of tivozanib and enzalutamide is more effective in delaying the progression of disease than when enzalutamide is given alone. This study will also determine whether treatment with the combination of the tivozanib and enzalutamide will have more side effects then treatment with enzalutamide alone.