Major scientific achievements include: the identification of mechanisms and methodologies that can be translated to enhance human T-cell responses to human tumor-associated antigens (TAAs), the identification and characterization of new targets that can be employed in vaccine-mediated immunotherapy, and the identification of agonist epitopes of human TAAs to enhance human T-cell responses. A major review has been written defining new paradigms to be employed in both vaccine clinical trial design and clinical trial endpoint. The field of cancer vaccines is currently in an active state of preclinical and clinical investigations. While no therapeutic cancer vaccine has to date been approved by the FDA, several new paradigms are emerging from recent clinical findings in both the use of combination therapy approaches and, perhaps more importantly, in clinical trial design and endpoint analyses. This review article/commentary reviewed recent clinical trials involving several different cancer vaccines from which data are emerging contrasting classical tumor response (RECIST) criteria with patient response in the manifestation of increased patient survival post-vaccine therapy. Also described are several strategies in which cancer vaccines can be exploited in combination with other agents and therapeutic modalities that are quite unique when compared with conventional combination therapies. This is most likely due to the phenomena that (a) cancer vaccines initiate a dynamic immune process that can be exploited in subsequent therapies, and (b) both radiation and certain chemotherapeutic agents have been shown to alter the phenotype of tumor cells as to render them more susceptible to T-cellmediated killing. Consequently, evidence is emerging from several studies in which patient cohorts who first receive a cancer vaccine (as contrasted with control cohorts) benefit clinically from subsequent therapies. The paradigm shifts put forth in this article for the use and clinical evaluation of cancer vaccines will hopefully result in vaccines being evaluated in more appropriate patient populations and with more appropriate clinical endpoints. Moreover, this article describes how cancer vaccines are quite distinct from conventional therapies and how vaccines can be used uniquely in combination therapeutic regimens. Other advances for this project include the identification of tumor antigens that are essential in advancing immune-based therapeutic interventions in cancer. Particularly attractive targets are molecules selectively expressed by the malignant cells and that are also essential for tumor progression. We have used a computer-based differential display (CDD) analysis tool for mining of expressed sequence tag (EST) clusters in the human Unigene database and identified Brachyury as a novel tumor antigen. Brachyury, a member of the T-box transcription factor family, is a key player in mesoderm specification during embryonic development. Transcription factors that control mesoderm, moreover, have been implicated in the epithelial-mesenchymal transition (EMT), which has been postulated to be a key step during tumor progression to metastasis. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis validated the in silico predictions and demonstrated Brachyury expression in tumors of the small intestine, stomach, kidney, bladder, uterus, ovary, and testis, as well as in cell lines derived from lung, colon, and prostate carcinomas, but not in the vast majority of the normal tissues tested. An HLAA0201 epitope of human Brachyury was identified that was able to expand T-lymphocytes from blood of cancer patients and normal donors with the ability to lyse Brachyury expressing tumor cells. To our knowledge, this is the first demonstration that (a) a T-box transcription factor and (b) a molecule implicated in mesodermal development, i.e., epithelial-mesenchymal transition (EMT), can be a potential target for human T-cell mediated cancer immunotherapy. This is important because this molecule appears to be necessary for the initiation and/or maintenance of the metastatic process. Other accomplishments of this project include: Cancer vaccines: moving beyond current paradigms. Schlom J, Arlen PM, and Gulley JL. Clin. Cancer Res. 13:3776-3782, 2007 The role of vaccine therapy in cancer: biology and practice. Schlom J, Gulley JL, and Arlen PM. Curr. Oncol. (in press) Identification of cytotoxic T-lymphocyte epitope(s) and its agonist epitope(s) of a novel target for vaccine therapy (PAGE4). Yokokawa J, Bera T, Palena C, Cereda V, Remondo C, Gulley JL, Arlen PM, Pastan I, Schlom J, and Tsang KY. Int. J. Cancer 121:595-605, 2007. The human T-box mesodermal transcription factor Brachyury is a candidate target for T-cell mediated cancer immunotherapy. Palena C, Polev DE, Tsang KY, Fernando RI, Litzinger M, Krukovskaya LL, Baranova AV, Kozlov AP, and Schlom J.Clin Cancer Res. 13:2471-2478, 2007. Population pharmacokinetics of humanized monoclonal antibody HuCC49∆CH2 and murine antibody CC49 in colorectal cancer patients. Fang L, Holford NH, Hinkle G, Cao X, Xiao JJ, Bloomston M, Gibbs S, Saif OH, Dalton JT, Chan KK, Schlom J, Martin EW Jr., and Sun D. J. Clin. Pharmacol. 47:227-237, 2007. Local delivery of vaccinia virus expressing multiple costimulatory molecules for the treatment of established tumors. Kaufman HL, Cohen S, Cheung K, DeRaffele, Mitcham J, Moroziewicz D, Schlom J, and Hesdorffer C.Human Gene Ther. 17:239-244, 2006. Preclinical and clinical studies of recombinant vaccines for carcinoma therapy. Arlen PM, Gulley JL, Madan RA, Hodge JW, and Schlom J. Crit. Rev. Immunol. (11th International Symposium of Immunobiology Supplement) (in press) Combining vaccines with conventional therapies for cancer. Arlen PM, Madan RA, Hodge JW, Schlom J, and Gulley JL. Update on Cancer Therapeutics (in press) Phase I trial of an enhanced prostate-specific antigenbased vaccine with antiCTLA-4 antibody in patients with metastatic androgen-independent prostate cancer. Theoret MR, Arlen PM, Pazdur M, Dahut WL, Schlom J, and Gulley JL. Clin. Genitourinary Cancer 5:347-350, 2007 Clinical safety of a viral vector-based prostate cancer vaccine strategy. rlen PM, Skarupa L, Pazdur M, Seetharam M, Tsang KY, Grosenbach DW, Feldman J, Poole DJ, Litzinger M, Steinberg SM, Jones E, Chen C, Marte J, Parnes H, Wright J, Dahut W, Schlom J, and Gulley JL. J. Urol. (in press; scheduled for Oct. 2007) A pilot study of CTLA-4 blockade after cancer vaccine failure in patients with advanced malignancy. OMahony D, Morris JC, Quinn C, Gao W, Wilson WH, Gause B, Pittaluga S, Neelapu S, Brown M, Fleisher TA, Gulley JL, Schlom J, Nussenblatt R, Albert P, Davis TA, Lowy I, Petrus M, Waldmann TA, and Janik JE. Clin. Cancer Res. 13:958-964, 2007. Combination chemotherapy and radiation of human squamous cell carcinoma of the head and neck augments CTL-mediated lysis. Gelbard A, Garnett CT, Abrams SI, Patel V, Gutkind JS, Palena C, Tsang KY, Schlom J, and Hodge JW. Clin. Cancer Res. 12:1897-1905, 2006. A randomized phase II study of concurrent docetaxel plus vaccine versus vaccine alone in metastatic androgen independent prostate cancer. Arlen PM, Gulley JL, Parker C, Skarupa L, Pazdur M, Panicali D, Beetham P, Tsang KY, Grosenbach DW, Feldman J, Steinberg SM, Jones E, Chen C, Marte J, Schlom J, and Dahut W. Clin Cancer Res 12:1260-1269, 2006. Vaccines and immunostimulants by Hodge JW, Schlom J, Abrams SI. In: Eds: Kufe DW, Bast Jr. RC, Hair WN, et al. Holland-Frei Cancer Medicine e. 7 Hamilton, Ontario: BC Decker, 2006, Chapter 51, pp. 786-801
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