A Phase 2 Multiple Dose, Multiple-Arm, Parallel Assignment Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of XmAb®20717 Alone or in Combination with Chemotherapy or Targeted Therapies in Selected Subjects with Metastatic

the purpose of this research study is to determine the safety and tolerability of XmAb20717 by itself and in combination with other anticancer therapies (Olaparib, Cabazitaxel, Docetaxel and Carboplatin). XmAb20717 has not been studied in a significant number of humans, therefore, some of its effects are unknown. XmAb20717 is an investigational antibody drug. An antibody is a kind of protein that your body makes to help fight infections. AmAb20717 is an investigational drug in this study because it has not been approved by the U.S. Food and Drug Administration (FDA), the health authority that gives approval for new medicines to be prescribed in the United States. The study will enroll subjects into on of 5 treatment groups based on specific information about your tumor.

Are you Eligible? (Inclusion Criteria)

• are you 18 years or older?
• do you have a histologically confirmed diagnosis of carcinoma of the prostate?
• are you able to undergo a biopsy of at least one metastatic site?
• Have you received prior treatment for your disease?