A Multicenter Trial to Identify Optimal Atezolizumab Biomarkers in the Setting of Recurrent Glioblastoma. The MOAB Trial

This study is testing a cancer immunotherapy drug called atezolizumab in people with recurrent glioblastoma — an aggressive brain tumor that has come back after treatment. Researchers want to find biological markers that predict who responds best to this therapy. **You may be eligible if...** - You are 18 or older - You have been diagnosed with IDH-wildtype glioblastoma that has come back after radiation and chemotherapy (first or second recurrence) - Tissue from your original tumor diagnosis is available - Your blood counts, kidney, and liver function are adequate **You may NOT be eligible if...** - You are on high-dose steroids - You have received prior immunotherapy for brain tumors - You are pregnant or breastfeeding - You have active autoimmune disease - You have serious heart or other organ problems Talk to your doctor to see if this trial is right for you.