Agenus Inc. (NASDAQ: AGEN), announced final results from a single-arm, multi-institutional, open-label, Phase 2 study showing that patients with newly diagnosed glioblastoma multiforme (GBM) who received Agenus' Prophage autologous cancer vaccine added to the standard of care treatment, lived nearly twice as long as expected. In this Phase 2 study, 50% of the patients lived for two years, an encouraging result for a cancer that often kills patients within one year 1-7. Prophage patients demonstrated a median overall survival of approximately 24 months and 33% of patients remain alive at 2 years and continue to be followed for survival.
"These data suggest that Prophage is generating an effective immune response which is translating into an extension in survival far beyond what is historically seen in patients with GBM. These data provide the impetus for a definitive, randomized clinical trial," said Andrew Parsa, MD, PhD,Principal Investigator of the study and the Michael J. Marchese Professor and Chair of the Department of Neurological Surgery at the Feinberg School of Medicine at Northwestern University. "Glioblastoma tumors are often resistant to standard therapies and the extended progression-free survival and proportion of long-term survivors is very encouraging."
In addition to the long-term survival data, vaccine treated patients had a median progression-free survival (PFS) of nearly 18 months, approximately two to three-times longer than patients treated with radiation and temozolomide alone1. Importantly, 22% of patients were alive and without progression at 24 months and continue to be followed for survival.
Interestingly, the response to Prophage seems to be more pronounced in those patients with less expression of the checkpoint ligand PDL-1 on the white blood cells, suggesting that combinations of Prophage with checkpoint modulators like PD-1 antagonists might make Prophage even more effective in a greater percentage of patients with GBM.
"We believe that Prophage may play an important role in changing the treatment paradigm for patients with GBM," said Garo Armen, PhD, CEO and chairman of Agenus Inc. "We are exploring partnerships for Phase 3 studies of Prophage in GBM. Additionally, we are excited about the potential combinations of Prophage with PD-1 antagonists and other checkpoint modulators in GBM."
Prophage is an autologous cancer vaccine, and each patient receives vaccine prepared from their own surgically resected tumor. As a result, the vaccine appears to help stimulate the patient's immune system to attack the tumor based on the spectrum of mutant proteins expressed by their own tumor. Since most cancers result from an accumulation of random mutations, which produce different mutant proteins in each patient, this approach is intended to individually tailor each patient's vaccine to optimally target the immune attack to that patient's actual tumor.
Phase 2 Prophage Study in Newly Diagnosed GBM
The Phase 2 single-arm trial of Prophage in patients with newly diagnosed GBM undergoing gross total resection includes 46 patients treated at eight centers (UCSF, Columbia, UPENN, Miami, Valley Hospital, Northern Westchester Hospital, Oklahoma, Johns Hopkins, and Northwestern) across the US. Patients were treated with surgical resection, radiation and temozolomide as the standard of care in addition to Prophage vaccination. The cohort was comparable to patients with surgically resectable newly diagnosed GBM on prognostic factors such as age, Karnofsky Performance Score, and MGMT methylation status. Analyses of data collected to date show more than 50% of the patients were alive at two years and patients continued to be followed. These results indicate considerable improvement when compared to expectations for patients treated with the standard of care (gross total resection plus radiation and temozolomide), which is 26% of patients alive at 24 months.
Median overall survival (OS), the primary endpoint of the trial, is 23.8 months and remains durable in patients treated with Prophage. For the standard of care alone, median OS survival rate is 14.6 months. PFS data remains durable with previous reports with a median PFS of 17.8 months and nearly 22% of patients alive without progression at 24 months.
The Phase 2 recurrent and newly diagnosed trials are being sponsored by Dr. Parsa and primarily have been supported through funding from the American Brain Tumor Association, Accelerated Brain Cancer Cure, National Brain Tumor Society, and National Cancer Institute Special Programs of Research Excellence. Dr. Parsa has not received any financial support or expense reimbursement for this work or for consulting activities on behalf of Agenus. He does not have an equity interest in Agenus or a financial relationship with the company.