3.3. Study Treatment T he trial interventions will consist of a single subcutaneous ( sc) immunization of PROSTVAC V or placebo in Week 1, followed by six PROSTVAC F or placebo immunizations administered in Weeks 3, 5, 9, 13, 17, and 21. Each immunization will be accompanied by administration of sc GM-CSF or placebo on the day of immunization and for the subsequent three days (sc injection within 5 mm of the original PROSTVAC VF or placebo injection site). The Treatment phase of this trial lasts for five months and is followed by an End-of- Treatment (Week 25)/Early Termination visit. During the Treatment phase, subject s will continue to be treated with vaccination the rapy through PSA and/or radiological progression. 3.4.