Agenus stock rose dramatically yesterday after the announcement of the results of a study on Prophage, its new brain cancer vaccine, revealed that life expectancy could be doubled for patients treated with the drug. The median life expectancy in 50 percent of patients newly diagnosed with glioblastoma multiforme (GBM) increased to two years when the drug was given in addition to standard treatment. After two years 33 percent of patients remain alive and continue to have survival rates followed.
The study was a Phase 2, single-arm, open-label, multi-institutional study supported through funding from the American Brain Tumor Association, National Brain Tumor Society, Accelerated Brain Cancer Cure and National Cancer Institute Special Programs of Research Excellence. It was sponsored by Dr. Andrew Parsa, the principal investigator on the study.
The new autologous cancer vaccine Prophage is made by Agenus from each patient’s own tumor tissue that has been surgically removed, meaning the vaccine is tailor-made for each individual. The vaccine appears to work by helping the patient’s immune system to attack the tumor. Most cancers result from random mutations that produce mutant proteins that are different in each patient. As Prophage is made from the patient’s tissue it is possible to specifically target each individual’s tumor.
Parsa said in a statement that the study data suggests that the immune response generated by Prophage is resulting in an increase in survival rates that are significantly longer than what has historically been seen in GBM patients. Company CEO Garo Armen says the company believes the new vaccine may play an important role in changing the standard treatment options for patients with GBM. According to the study, patients treated with Agenus’ new brain cancer vaccine not only had double the life expectancy, but showed a median progression-free survival of nearly 18 months, approximately 2-3 times longer than with traditional treatments alone..
Glioblastomas can grow rapidly, and the median survival can be as low as 14.6 months. Two-year survival rates are only about 30 percent. The tumors grow from astrocytes, the star-shaped cells that make up the brain’s supportive tissue. They are generally highly malignant because they reproduce quickly. GBM is usually found in the cerebral hemispheres of the brain, but also appear in the spinal cord, or other brain locations. The vaccine appears to be most effective with patients in the early stages of glioblastoma tumors.
Symptoms of GBM are usually related to increased pressure in the brain, and include drowsiness, headache, nausea and vomiting. Patients may also develop symptoms such as memory and speech difficulty, weakness on one side of the body, and visual changes. GBM tumors account for about 17 percent of all primary brain tumors, affect more men than women, and increase in frequency with age. Their cause is unknown, and they are very difficult to remove because of their finger-like tentacles. Treatment of GBM is also difficult because of the many different types of cells contained in the tumors. Some of the cells respond well to treatment, while others may show no effect.
The study included 46 newly diagnosed GBM patients, treated at eight centers across the U.S. In addition to Prophage vaccination the patients were given the standard forms of treatment which include radiation, surgical resection and temozolomide. The study showed that Agenus’ new brain cancer vaccine, when combined with established forms of treatment, doubled life expectancy as measured by median survival rates.
By Beth A. Balen