Data from Investigator-Sponsored Trial of Oncophage(R) Cancer Vaccine in Glioma Presented at American Association of Neurological Surgeons Annual Meeting.

Oncophage Vaccination Associated With Significant Tumor-Specific Immune Response in All 12 Patients

WASHINGTON -- Antigenics Inc. (NASDAQ: AGEN) today announced an oral presentation of updated data from a Phase 1/2 investigator-sponsored trial of the company's investigational cancer vaccine Oncophage([R]) (vitespen) in recurrent, high-grade glioma at the 75th annual meeting of the American Association of Neurological Surgeons (AANS; abstract #606). Preliminary results from the study, being conducted at the Brain Tumor Research Center at the University of California, San Francisco, showed that Oncophage vaccination was associated with significant tumor-specific immune response in all 12 treated patients from baseline (P < .001), as determined using three separate immune response assessments. Of the 12 patients treated, four continue to receive Oncophage and eight have completed treatment and are evaluable for overall survival. Seven of these eight evaluable patients have exceeded the historical median benchmark of 6.5 months survival from time of recurrence.

"In this trial we have observed a correlation between immune response as a result of Oncophage vaccination and potential clinical benefit," said Andrew T. Parsa, MD, PhD, assistant professor in the department of neurological surgery at the University of California, San Francisco, and recipient of the 2007 Young Investigator Award at AANS. "Understanding that the patients in this trial represent the most challenging patient population to treat, we are highly encouraged by the prolonged improvement in overall survival compared with historical controls."

Commenting on the paper presented at AANS, Henry Brem, MD, director of neurosurgery at Johns Hopkins, noted, "This is an encouraging study of a therapeutic cancer vaccine that targets multiple tumor antigens, supported by rigorous immunomonitoring. A larger Phase 2 trial is certainly warranted to evaluate efficacy." Dr. Brem is a developer of Gliadel([R]) Wafer (polifeprosan 20 with carmustine implant, MGI Pharma), the first approved local therapy for glioma.

Derived from each individual's tumor, Oncophage contains the 'antigenic fingerprint' of the patient's particular cancer and is designed to reprogram the body's immune system to target only cancer cells bearing this fingerprint. Oncophage is intended to leave healthy tissue unaffected and limit the debilitating side effects typically associated with traditional cancer treatments such as chemotherapy and radiation therapy. Oncophage has been granted fast track and orphan drug designations from the US Food and Drug Administration (FDA) in both metastatic melanoma and renal cell carcinoma.

Study Findings

The investigator-sponsored Phase 1/2 study is designed to evaluate the feasibility, safety and activity of Oncophage vaccination in patients with recurrent, high-grade glioma. The trial involves two cohorts of six patients, both receiving a minimum of four Oncophage injections: the first cohort receives biweekly vaccinations; the second cohort receives weekly vaccinations. Patients are monitored for immune response before and after Oncophage treatment using three different techniques.

According to investigators, no adverse events or toxicity identified were considered attributable to the vaccine. A tumor-specific immune response was detected after vaccination in all 12 patients. The investigators will continue to follow patients for overall survival. Researchers plan to present further results from the Phase 1/2 trial of Oncophage in late 2007 and submit the findings for peer-review publication. Based on these results, the Phase 2 portion of this study is expected to move forward in mid-2007.

"Our goal is to change the management of recurrent glioma from a life threatening disease, in which survival rates are typically 25 to 26 weeks, into a chronic disease with extended survival and improved quality of life for patients," said Dr. Parsa. "Although our survival data are encouraging, a larger Phase 2 study will be required to determine the benefit of Oncophage for patients with recurrent glioma. The consistent, tumor-specific immune response seen in these patients suggests that in the right patient population, Oncophage could have a significant impact."

About Brain and Spinal Cord Tumors 

Glioma is a cancer affecting the central nervous system that begins in glial cells (connective tissue cells that surround and support nerve cells). Malignant glioma is currently a fatal disease. The American Cancer Society estimates that 20,500 malignant tumors of the brain or spinal cord will be diagnosed during 2007 in the United States, and that about 12,740 people will die from these tumors. 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.

About Antigenics

Antigenics (NASDAQ: AGEN) is a biotechnology company working to develop treatments for cancers and infectious diseases. The company's investigational product portfolio includes Oncophage([R]) (vitespen), a patient-specific therapeutic cancer vaccine being evaluated in several indications; Aroplatin[TM] (L-NDDP), a liposomal, third-generation platinum chemotherapeutic; AG-707, a therapeutic vaccine for the treatment of genital herpes; and QS-21, an adjuvant being evaluated by Antigenics' corporate partners in several late-stage clinical trials. For more information, please visit www.antigenics.com.

This press release contains forward-looking information, including statements regarding the potential safety and activity of Oncophage in patients with glioma, publication plans and future clinical trials. These risks and uncertainties include, among others, the risk that a small investigator-sponsored study in 12 patients is not representative of what will be shown in larger trials that could support registration; and the factors described under Factors That May Impact Future Results in the Management's Discussion and Analysis of Financial Condition and Results of Operations section of Antigenics' Annual Report on Form 10-K as filed with the Securities and Exchange Commission on March 16, 2007. 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.