The Phase II results are in for Agenus' autologous cancer vaccine Prophage: According to the immuno-oncology firm, the single-arm, multi-institutional, open-label study showed that patients with newly diagnosed glioblastoma multiforme (GBM) who received Prophage in addition to the standard of care treatment lived nearly twice as long as expected.
Patients treated with the vaccine also had a median progression-free survival (PFS) of nearly 18 months; Agenus says this is around two to three-times longer than patients treated with radiation and temozolomide alone. Also, 22% of patients were alive and without progression at 24 months.
Each patient received vaccine tailor-made for them from their own surgically resected tumor; as such, the vaccine works by stimulating the patient’s immune system to attack the tumor based on the spectrum of mutant proteins their own tumor expresses. Agenus adds that response to Prophage seems to be more pronounced in 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 may make Prophage even more effective in a greater percentage of patients with GBM.
"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," Andrew Parsa, M.D., Ph.D., the study's principal investigator, said in a statement. "These data provide the impetus for a definitive, randomized clinical trial." Dr. Parsa is also the Michael J. Marchese Professor and Chair of the Department of Neurological Surgery at the Feinberg School of Medicine at Northwestern University.