The main toxicity was grade 2 (at the injection site) with no grade 3 or greater toxicity observed. with 12/15 patients living longer than predicted (p=0.035). Treg suppressive function was shown to AG-014699 (Rucaparib) decrease following vaccine in patients surviving longer than predicted, and increase in patients surviving less than predicted. This hypothesis-generating study provides evidence that patients with more indolent mCRPC (Halabi predicted survival 18 months) may best benefit from vaccine therapy. == Electronic supplementary material == The online version of this article (doi:10.1007/s00262-009-0782-8) contains supplementary material, which is available to authorized users. Keywords:Malignancy vaccine, Immunotherapy, Prostate malignancy, Overall survival, PSATRICOM, PROSTVAC == Introduction == Prostate malignancy is the most common noncutaneous malignancy among men in the United States, with an estimated 192,280 diagnosed each year, AG-014699 (Rucaparib) resulting in approximately 27,360 deaths [1]. While Gleason score has traditionally been a main prognostic indication for main prostate malignancy, the Halabi nomogram [2] is usually increasingly being used as a prognostic indication for overall survival of patients with metastatic castration-resistant prostate malignancy (CRPC). The Halabi nomogram is usually a pretreatment prognostic model derived from results of six individual Malignancy and Leukemia Group B (CALGB) trials of 1 1,101 patients with metastatic CRPC; it is based on AG-014699 (Rucaparib) seven predictors of overall survival: presence of visceral disease, Gleason sum, performance status, PSA, lactate dehydrogenase, alkaline phosphatase, and hemoglobin. It is important to note that this model predicts overall survival based on the outcomes of patients receiving chemotherapy- or hormonal-based treatment for metastatic CRPC, and does not include untreated patients. The use of this model to compare predicted survival with actual overall survival has been previously reported [3]. Only one drug, docetaxel, has been shown to lengthen overall survival (by approximately 23 months) in men with metastatic CRPC [4]. This dearth of approved therapeutics is the impetus for screening novel agents in AG-014699 (Rucaparib) this disease. An alternative approach for prostate malignancy therapy is the use of vaccines directed against prostate-associated antigens. A recent Phase III trial [5] employing the sipuleucel-T vaccine (PAP-GM-CSF fusion protein-pulsed analogous antigen-presenting cells from leukapheresis) exhibited improved median overall survival (25.9 months for vaccine vs. 21.4 months for control,p=0.032) in patients with metastatic castrate-resistant prostate malignancy (mCRPC). Another immunotherapy platform is usually a vector-based vaccine directed against prostate-specific Rplp1 antigen (PSA). Preclinical studies have previously exhibited the efficacy of (a) diversified prime/increase vaccination regimens employing recombinant vaccinia (rV-) as primary and multiple recombinant fowlpox (rF-) boosts [6]; (b) the insertion of one or more T-cell costimulatory molecules into the vector along with the transgene for the tumor-associated antigen (TAA) [7,8]; and (c) the use of granulocytemacrophage colony-stimulating factor (GM-CSF) as a biologic adjuvant to enhance recruitment of dendritic cells [9]. GM-CSF can be administered as a recombinant protein or by inserting the GM-CSF gene into an rF-vector (rFGM-CSF). Several previous clinical trials including recombinant poxvirus vectors encoding the transgene for PSA have shown evidence of clinical benefit. In a phase I study employing rVPSA alone, PSA levels in 13 of 33 men stabilized for at least 6 months post-vaccination, and nine patients remained stable for 1125 months [10]. A randomized phase II trial employing rVPSA (V) and/or rFPSA (F) in patients with biochemical progression after local therapy has also been completed [11]. At a median follow-up of 50 months [12],.