New Orleans, June 7, 2004 � Therion Biologics Corporation today presented data supporting the safety profile of the company�s therapeutic cancer vaccines and suggesting early evidence of extended overall survival in patients with advanced pancreatic cancer. In two separate Phase I studies, median overall survival was 7.9 months and at least 5.3 months, respectively, compared to an anticipated median overall survival of approximately three months, based on historical controls. The data were presented at the 40th Annual Meeting of the American Society of Clinical Oncology (ASCO). These data, along with additional safety data from 30 previous trials, also presented at the meeting today, form the basis for Therion�s upcoming pivotal trial of PANVAC-VF for the treatment of metastatic pancreatic cancer, targeted to begin this summer.

�Pancreatic cancer remains one of the more difficult cancers to treat with few available therapies,� said Thomas Schuetz, M.D., Ph.D., Chief Medical Officer of Therion. �In light of a short anticipated overall survival, the results from these two small studies are very intriguing and clearly warrant a larger, randomized evaluation of PANVAC-VF as a potential new treatment option for advanced pancreatic cancer.�

Dr. Schuetz presented the Phase I study results from Abstract #2564 today. Howard Kaufman, M.D., Director of the Tumor Immunotherapy Program at Columbia University, also presented results from Abstract #2513 supporting the safety profile of Therion�s cancer vaccines today.

The Phase III study of PANVAC-VF, the first pivotal trial of a Therion therapeutic vaccine, will be conducted under the guidance of a Special Protocol Assessment (SPA) provided by the FDA. The SPA indicates that, if the trial successfully meets its primary endpoint of overall survival, the data will provide the basis for an efficacy claim in a marketing application for PANVAC-VF.

�Therion�s SPA agreement to begin a Phase III trial comes less than one year after the company filed the Investigational New Drug Application for PANVAC-VF,� said Mark Leuchtenberger, President and Chief Executive Officer of Therion. �This expedited timeline is testament to our step-wise development strategy to optimize our vaccine candidates through extensive clinical studies with precursor product candidates, a strategy also employed in the development of PROSTVAC^�-VF, currently in Phase II clinical evaluation for prostate cancer.�

Study Details:
PANVAC-VF is designed to stimulate the immune system to target and destroy cancer cells expressing two proteins (or antigens), carcinoembryonic antigen (CEA) and mucin-1 (MUC-1), found on over 90 percent of pancreatic tumor cells. Therion�s vaccines are administered via subcutaneous injection in a �prime-boost� fashion, employing vaccinia as the priming vector, followed by sequential doses with a fowlpox vector. The vaccines also incorporate TRICOM�, Therion�s proprietary triad of costimulatory molecules (B7.1, ICAM-1 and LFA-3), designed to enhance and sustain a targeted immune response against tumor cells.

Therion conducted two open-label Phase I clinical studies, each with the primary objective of safety. The studies enrolled a total of 22 patients with advanced (Stage III or IV) pancreatic cancer, 20 of whom had metastatic disease (Stage IV); all had received prior chemotherapy. Based on a review of multiple Phase III studies involving other chemotherapeutics, the expected median overall survival of this patient population is approximately 3 months.

Study PAN 1-1 enrolled 12 patients to evaluate Therion�s early-generation pancreatic cancer vaccine, CEA-VF/TRICOM�. The vaccine regimen consisted of an initial priming dose of Vaccinia-CEA/TRICOM (V) and Vaccinia-MUC-1 on day one, followed by a boosting dose of Fowlpox-CEA/TRICOM (F) every two weeks for a total of six weeks. All vaccines were administered with GM-CSF (a cytokine designed to enhance T-cell response). Patients were also given the opportunity to participate in an extension phase and continue treatment with Fowlpox-CEA/TRICOM on a monthly basis. The median overall survival in the study was 7.9 months, with 58 percent (n=7) of patients alive at week 24. In addition, 33 percent (n=4) of the patients in the study remain alive at 13 months.

Study TBC-PAN-002, also an open label Phase I study, enrolled 10 patients to evaluate PANVAC-VF, Therion�s lead pancreatic cancer vaccine candidate targeted to enter a pivotal Phase III trial this summer. A priming dose of PANVAC-V was administered on day one, followed by boosting doses of PANVAC-F delivered every two weeks for a total of six weeks. Similar to PAN 1-1, this study also provided the option for patients to continue receiving booster vaccinations on a monthly basis as part of an extension arm. The median overall survival has not yet been rendered but will be greater than 5.3 months.

In both Phase I studies, there were no serious adverse events related to the vaccines reported. Common side effects included fever, chills and fatigue. The safety profile of Therion�s vaccine candidates was reinforced through a review of safety data from approximately 30 clinical studies in over 700 patients, presented by Dr. Kaufman. The study reviewed trials conducted in a variety of advanced cancer patients, including cancers of the pancreas, colon and prostate, in which Therion�s vaccines were administered through intradermal, subcutaneous, intramuscular, intratumoral, or intravenous routes. Seven serious adverse events were reported that were specific to intravenous administration: hypotension (n=5), rash (n=1) and fever/chills (n=1). No serious adverse events associated with subcutaneous injection were reported. Common side effects included fever, chills and fatigue.

In addition to Dr. Schuetz, Phase I study authors included J. Marshall, H.L. Kaufman, H. Safran, and D. Panicali. In addition to Dr. Kaufman, safety profile authors included R. DiPaola, M. von Mehren, J. Marshall, L. Lyerly, H. Streicher, J. Schlom, D. Panicali and T. Schuetz.

About Pancreatic Cancer
Pancreatic cancer remains one of the deadliest forms of cancer, affecting over 30,000 Americans each year. More than 95 percent of pancreatic cancer patients die from the disease. Current treatments include surgery, chemotherapy and radiation. There is currently no FDA-approved treatment for patients who do not respond to chemotherapy.

About Therion Biologics Corporation
Therion Biologics Corporation develops therapeutic vaccines that aim to extend and improve the lives of cancer patients. The company has two lead product candidates: PANVAC-VF, entering a Phase III clinical trial for pancreatic cancer; and PROSTVAC^�-VF in a Phase II clinical trial for prostate cancer. The company is applying its technology to develop its vaccine pipeline, including treatments for breast cancer, lung cancer, and the prevention of AIDS. Therion is also developing a vaccine for colon cancer with its strategic partner, Aventis Pasteur, Ltd. Through Therion�s longstanding partnerships with the National Cancer Institute (NCI) and a network of renowned clinical institutions, over 700 patients in more than 30 clinical trials have been treated with Therion�s vaccine candidates. For more information, please visit www.therionbio.com.