This is a multicenter (when more than one hospital or medical school team work on a medical research study), randomized (the study drug is assigned by chance), double-blind (neither physician nor participant knows the treatment that the participant receives) study of intetumumab in combination with docetaxel and prednisone for the first-line treatment of participants with metastatic hormone-refractory prostate cancer. There will be 2 study groups. One group will receive intetumumab in combination with docetaxel and prednisone (study treatment) and the other group will receive placebo (an inactive substance that is compared with a drug to test whether the drug has a real effect in a clinical trial) matching to intetumumab in combination with docetaxel and prednisone (control treatment). The duration of treatment will be 6 months. Participants who respond to treatment with stable disease or better will receive extended treatment until disease progression (disease worsening) or for an additional 6 months, whichever occurs first. Treatment can be further continued with the sponsor's discretion after receiving 6 months of extended treatment, if participant response to the treatment (with stable disease, partial response, or complete response). Participants who have confirmed progressive disease while receiving study treatment may have their treatment unblinded (participants will know the name of drug which was given to them), if they wish to be considered for alternative treatment. Participants who were receiving the control treatment will be considered to have completed the study treatment, and will have the option to receive alternative treatment. Alternative treatment will either be intetumumab along with docetaxel and prednisone or intetumumab alone. Participants' safety will be monitored throughout the study.
