Cambridge, MA � July 28, 2004 � Therion Biologics Corporation this morning announced that it has been selected as a member of FierceBiotech�s annual �Fierce 15,� a list of the top emerging biotech companies of 2004.

FierceBiotech Editor-in-Chief John D. Carroll lauded Therion�s research efforts and clinical progress in 2004, saying, �Therion�s therapeutic cancer vaccine candidates have repeatedly demonstrated encouraging clinical results and continue to advance in the clinic.�

Based in Cambridge, Massachusetts, 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, in a Phase III clinical trial for pancreatic cancer; and PROSTVAC�-VF in a Phase II clinical trial for prostate cancer. Therion is well positioned to commercialize the next generation of cancer therapeutics as a fully integrated, clinical-stage biotechnology company, with strong research, clinical and manufacturing capabilities.

�We are honored to receive FierceBiotech�s recognition,� said Mark Leuchtenberger, President and Chief Executive Officer of Therion Biologics Corporation. �Being selected as a member of The Fierce 15 highlights Therion�s growing prominence in the biotech industry and underscores our commitment to improving the lives of cancer patients. We recently initiated our first pivotal trial of PANVAC-VF in pancreatic cancer and have an ongoing Phase II clinical trial of PROSTVAC�-VF in prostate cancer underway, placing us on an accelerated path towards commercialization.�

The Fierce 15 celebrates the spirit of being �fierce� � daring to be innovative and aggressive, even in an industry with a long time-to-market. The list of Fierce 15 companies is available in today�s issue of FierceBiotech and on the FierceBiotech web site at http://www.fiercebiotech.com.

This year�s Fierce 15 list also includes a Massachusetts company that is developing implantable bionics for the severely disabled, a German company developing antibody-based cancer treatments, a California company that is making inroads on the development of targeted medicines, and other privately-held companies innovating treatments for cancer, heart disease, cystic fibrosis and other conditions.
FierceBiotech publishes a daily email briefing read by more than 31,000 executives in over 100 countries. Since its launch in March 2000, FierceBiotech has been recognized as a must-read source of news and intelligence for the biotech industry.

About Therion Biologics
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, currently in a Phase III clinical trial for pancreatic cancer; and PROSTVAC�-VF currently 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.

About FierceBiotech
FierceBiotech is an internationally recognized email newsletter for the biotech industry. Every business day, more than 31,000 executives in over 100 countries rely on FierceBiotech for a quick, authoritative briefing on the day�s top stories. It is published by FierceMarkets, Inc., a business publishing company based in Washington, DC.