Glioblastoma (GBM) is a highly malignant form of brain tumor. Its cells reproduce quickly and are nourished by a large network of blood vessels, fueling rapid growth and making it the most deadly of brain cancers. Because of its aggressiveness, GBM is categorized as a high grade glioma (HGG).
GBM is one of the most common forms of HGG, with new diagnoses estimated to be approximately 12,500 in 2018 the United States. It accounts for about half of all brain and central nervous system cancers and is reported to have a five-year survival rate of about five percent.
Patients with newly diagnosed GBM who receive maximal therapy had a median survival of 14.6, 16.1 or 16.8 months according to three Phase 3 clinical trials published in the New England Journal of Medicine. Current standard of care therapy for patients with newly diagnosed GBM includes surgery, radiation therapy and chemotherapy.
GBM tumors can be difficult to treat because they are made up of many different types of cells, which may not respond to the same type of therapy. Studies have identified several important predictive or prognostic biomarkers including MGMT promoter methylation, IDH mutation status, 1p19q co-deletion, and ATRX expression loss.
Symptoms vary depending on the location and size of the tumor, but most patients experience pressure in the brain as a result of the tumor’s fast growth.
Given the relatively young age at diagnosis, more years of productive life are lost in patients with brain tumors compared to other cancers.
Tocagen is developing an investigational therapy to treat GBM and anaplastic astrocytoma, which is under investigation in an ongoing Phase 3 clinical trial, Toca 5. The Toca 5 trial is fully enrolled and not recruiting patients.
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