This randomized clinical trial (RTOG-0825) for patients with newly diagnosed glioblastoma (GBM) will determine if the addition of bevacizumab to the current standard-of-care therapy, concurrent chemoradiation and adjuvant temozolomide, improves patient outcomes. Prior studies have shown that patients with a methylated DNA-repair gene (MGMT) are more likely to respond to temozolomide-based therapy and encouraging response rates have been demonstrated in phase 2 trials of bevaciuzmab for treatment in patients with recurrent glioblastoma. This trial is designed to provide a definitive evaluation of the combination therapy in newly diagnosed GBM with respect to progression-free and overall survival.
Approximately 720 patients will be enrolled in RTOG-0825. The trial requires histologic confirmation of GBM and analysis of tumor MGMT status through central pathology review after patient registration on the study but prior to treatment assignment. All patients will receive standard therapy of radiation and daily temozolomide for 3 weeks. Patients will be stratified by the MGMT methylation status and molecular profile of their tumors to receive either standard therapy plus bevacizumab or a continuation of their standard therapy plus placebo. The evaluation of MGMT is based on studies that have shown that methylation (silencing) of the MGMT gene promoter may help to identify brain tumors more likely to respond to standard chemotherapeutic agents. In addition to progression-free and overall survival, the study will include evaluation of tumor molecular profiles for prognostic factors, neurocognitive function, health-related quality of life, patient-reported outcomes, treatment side-effects, and the interactions between these factors. The trial also includes an advanced MRI imaging study in collaboration with the American College of Radiology Imaging Network (ACRIN).