Surgical Pembro +/- Olaparib w TMZ for rGBM

Required: IDH1 wild-type

IDH wildtype glioblastoma by IDHR132H immunohistochemistry

Required: IDH2 wild-type

IDH wildtype glioblastoma by IDHR132H immunohistochemistry

Excluded: 1P/19Q co-deletion

Prior evidence of 1p/19q co-deletion

Allowed: EGFR amplification

IDH wildtype diffuse glioma with molecularly features of glioblastoma (EGFR amplification, TERT promoter mutation, or concurrent gain of Chromosome 7 and loss of Chromosome 10)

Allowed: TERT promoter mutation

IDH wildtype diffuse glioma with molecularly features of glioblastoma (EGFR amplification, TERT promoter mutation, or concurrent gain of Chromosome 7 and loss of Chromosome 10)

Must have received: radiation therapy — initial therapy

First relapse is defined as progression following initial therapy

Cannot have received: PARP inhibitor (olaparib, niraparib)

Participants who have received prior treatment with a PARP inhibitor (e.g. olaparib, niraparib)

Cannot have received: anti-VEGF targeted agent (bevacizumab, cediranib, aflibercept, vandetanib, cabozantinib, sunitinib)

Participants who have received anti-VEGF targeted agents (e.g. bevacizumab, cediranib, aflibercept, vandetanib, cabozantinib, sunitinib etc.)

Cannot have received: anti-PD-1 therapy

Participants who have received prior therapy with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) antibody (including ipilimumab or any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathways)

Cannot have received: viral therapy or vaccine for glioblastoma

Participants who have received prior viral therapy or vaccines for glioblastoma