Histopathologic Review Of Suspected Disease Progression In Patients With Recurrent Glioblastoma (Gbm) Receiving Nivolumab +/- Ipilimumab: Checkmate 143.

2001Background: Patients treated with immunotherapies can have a transient increase in lesion size due to immune cell infiltration that is suggestive of disease progression, but undergo subsequent regression with continued treatment. For patients with GBM, distinguishing progression from immune-related treatment effects using neuroimaging is challenging. Histopathologic examination of tumors could show the activity of immunotherapies in GBM and potentially minimize premature discontinuation of therapy and increase clinical benefit. Neuropathologic data from patients with recurrent GBM treated in CheckMate 143 who underwent biopsy/resection after suspected progression are presented. Methods: Patients received nivolumab 3 mg/kg (nivo 3) Q2W or nivo 3 + ipilimumab 1 mg/kg (ipi 1) Q3W × 4 doses then nivo 3 Q2W. Tissue collected from patients with suspected radiologic progression was submitted for blinded central review by 2 neuropathologists. Potentially significant treatment effect was defined as ≥30% necros...