In April 2009, the World Vaccine Congress named Oncophage as the best therapeutic vaccine.About Brain and Spinal Cord Tumors The American Cancer Society estimated that 22,070 malignant tumors of the brain or spinal cord would be diagnosed during 2009 in the United States, and that about 12,920 people would die from these tumors. Primary malignant brain tumors are uniformly fatal, and the five-year survival rate for the highest grade of malignant glial neoplasm, glioblastoma multiforme, is less than 2 percent. Brain and spinal cord tumors account for about 1 percent of all cancers and 2 percent of all cancer-related deaths. About UCSF UCSF is a leading university that consistently defines health care worldwide by conducting advanced biomedical research, educating graduate students in the life sciences, and providing complex patient care. For more information, please visit www.ucsf.edu. Dr. Parsa has not received any financial support or travel expense reimbursement for this presentation or for consulting activities on behalf of Antigenics. Dr. Parsa does not have an equity interest in Antigenics or other financial relationship with the company. About the American Brain Tumor Association For more than 37 years, the American Brain Tumor Association has provided critical funding to researchers working toward breakthroughs in brain tumor diagnosis, treatment and care, with the ultimate goal of finding a cure. The ABTA is also the recognized resource for comprehensive information and compassionate support for the brain tumor patients, families and caregivers who are living with this disease. About Antigenics Antigenics (NASDAQ: AGEN) is a biotechnology company working to develop treatments for cancers and infectious diseases. For more information, please visit www.antigenics.com. This press release contains forward-looking statements, including statements regarding trial enrollment expectations, availability of data and registrational strategies, the potential of Oncophage to improve overall survival and the potential advantage of Oncophage in effectively generating an immune response. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others, that the results of the Phase 2 trials of Oncophage in glioma may be unfavorable; even if the results from these trials are positive, significant additional trials, the outcome of which are uncertain, would be required before submitting an application for marketing approval; decisions by physicians, patients, and regulatory agencies; and the factors described under the Risk Factors section of Antigenics’ Form 10-Q as filed with the Securities and Exchange Commission for the quarter ended March 31, 2010. Antigenics cautions investors not to place considerable reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this document, and Antigenics undertakes no obligation to update or revise the statements. All forward- looking statements are expressly qualified in their entirety by this cautionary statement. Antigenics’ business is subject to substantial risks and uncertainties, including those identified above. When evaluating Antigenics’ business and securities, investors should give careful consideration to these risks and uncertainties.