LEXINGTON, Mass., May 1, 2013 (GLOBE NEWSWIRE) -- Agenus Inc. (Nasdaq:AGEN) today announced that preliminary data from a Phase 2 clinical trial showed that newly diagnosed glioblastoma multiforme (GBM) patients treated with Prophage G-100 (Heat Shock Protein-Peptide Complex-96, HSPPC-96) vaccine plus the standard of care showed a 146% increase in progression free survival (PFS) and a 60% increase in overall survival (OS) as compared to the standard of care alone. Results were presented today by Orin Bloch, M.D., of the Department of Neurological Surgery, University of California San Francisco (UCSF), during Plenary Session III at the 81 st American Association of Neurological Surgeons (AANS) Annual Scientific Meeting in New Orleans, Louisiana. Dr. Bloch is a lead medical scientist working on the study at UCSF with Andrew T. Parsa, M.D., Ph.D., lead clinical investigator and study sponsor. Dr. Parsa is currently at UCSF and will soon join Northwestern University as the newly appointed Chair of the Department of Neurological Surgery. "Cancer vaccines offer the hope of benefit without toxicity for patients with glioblastoma," said Dr. Parsa. "Data from the HSPPC-96 trials have been consistently positive in both recurrent and newly diagnosed GBM settings, supporting the premise that this vaccine may one day become part of the standard of care. We are now advancing HSPPC-96 in recurrent GBM in the largest, randomized brain tumor trial ever funded by the NCI and the largest vaccine study ever conducted with Avastin." Phase 2 HSPPC-96 Data in Newly Diagnosed GBM Patients The single-arm, Phase 2 trial of HSPPC-96 in patients with newly diagnosed GBM included a total of 46 patients treated at eight centers across the United States. Patients were treated with radiation and temozolomide as the standard of care in addition to receiving HSPPC-96 vaccination. Analyses of data collected to date show a median PFS of 17 months; these results compare favorably to the PFS reported with the standard of care of radiation and temozolomide alone, which is 6.9 months.  Median OS, which is the primary endpoint for the trial, in patients treated with HSPPC-96 is currently 23.3 months. The majority of enrolled patients in the trial are still being followed and it is expected that PFS and OS will continue to mature as more data are collected. For the standard of care involving treatment with radiation and temozolomide alone, median OS survival is 14.6 months.  A total of 32 patients enrolled and treated at UCSF also underwent testing for expression of B7-H1 in blood samples taken prior to surgery. Glioblastoma has been shown to induce systemic immunosuppression through stimulation of B7-H1 expression, which could affect the efficacy of immunotherapy. These exploratory analyses showed that patients with low expression of B7-H1 (53%) had better PFS (21.6 months) than those with high B7-H1 (47%) expression (11.4 months). This finding may have the potential to help identify a more responsive patient population for future trials.