Use Of Immunotherapy In Recurrent Glioblastoma.

e13523Background: With the recent explosion of interest in immunotherapy to treat cancer, it has moved into management of glioblastoma (GBM). Several trials are ongoing, investigating use of checkpoint inhibition for newly diagnosed and recurrent GBM. Methods: We reviewed the records of patients with recurrent glioblastoma (including gliosarcoma). Six of the eight patients demonstrated PD-1 positivity via immunohistochemical (IHC) staining. Two patients demonstrated PD-L1 positivity as 2+ staining intensity via IHC. Patients were managed with checkpoint inhibitors for at least four weeks. When feasible, patients had tumor profiling of initial tumor and recurrent tumor. Patients were followed for response, progression, and survival. Results: Eight patients were identified with recurrent GBM who received immunotherapy with checkpoint inhibitors. They ranged from first through fifth recurrence following radiation and temozolomide. Three patients received pembrolizumab. Of those, two were PD-L1 positive. Five...