Tumor-Specific Antigens Therion�s lead clinical programs are focused on prostate cancer and pancreatic cancer. To best target these diseases, the Company has identified several tumor-associated antigens that are specific to these disease indications. Therion is currently focused on three antigens for inclusion into its cancer vaccines: Prostate specific antigen (PSA), carcinoembryonic antigen (CEA) and mucin-1 (MUC-1). Prostate Specific Antigen: PSA is a protein produced by prostate cancer cells. Elevated blood levels of PSA serve as a marker of prostate cancer progression. PROSTVAC-VF/TRICOM�, one of Therion�s lead clinical candidates, is designed to train the immune system to recognize PSA and to elicit an immune response against prostate cancer. Carcinoembryonic Antigen: CEA is a protein that is associated with a number of cancers, including colorectal, pancreatic, lung and breast. In fact, it is estimated that the majority of colorectal, pancreatic and lung cancers over-express CEA. CEA acts as one of two tumor-targeting proteins in its lead product candidate for pancreatic cancer. Therion's Approach Technology Platform Pox Virus Vectors Tumor Specific Antigens MUC-1: MUC-1 is a protein that is over-expressed on a number of endothelial cancers, including pancreatic, breast, colorectal and lung. Therion is currently evaluating one of its lead candidates, PANVAC-VF/TRICOM�, which utilizes both CEA and MUC-1, to treat pancreatic cancer. In addition, Therion is investigating therapeutic opportunities for other cancers that express both the CEA and MUC-1 antigens, including breast cancer. Co-Stimulatory Molecules Through multiple clinical trials, Therion has concluded that the inclusion of certain co-stimulatory molecules in its cancer vaccines can optimize antigen presentation and activation of the immune system. Specifically, these molecules appear to play an important role in the recruitment of cytotoxic T-cells necessary for tumor destruction. Therion is using the co-stimulatory molecules ICAM-1, B7.1and LFA-3, TRICOM� (which stands for a TRIad of CO-stimulatory Molecules) as part of its pox virus vector-based approach to cancer immunotherapy. TRICOM� is an integral component of Therion�s lead product candidate, PROSTVAC-VF/TRICOM�, currently in clinical investigation for the treatment of metastatic prostate cancer. TRICOM� is also a key component of Therion�s other product development programs, including pancreatic, colorectal, and breast cancer and melanoma. Back to the top Copyright © Therion Biologics Corporation.