Window Trial of Fluorescently Labeled Nivolumab-IRDye800 (Nivo800) in High Grade Glioma (HGG)

Participants will receive a single infusion of nivolumab following an infusion of nivolumab-IRDye800 (nivo800), for a combined total dose of 240 mg. This dosing applies to all cohorts except Cohort 1, which is designated as the safety group. Each cohort, other than Cohort 1, will receive no more than 240 mg in total of nivolumab and nivo800 combined. Participants will then undergo planned Standard of Care (SOC) surgical resection 1 to 4 days after the infusion.

Participants will receive an infusion of nivolumab-IRDye800 (nivo800). Nivo800 has never been assessed in patients before and therefore Cohort 1 will receive only a test dose to determine the safety (3 participants). Cohorts 2-4 will receive escalating doses of nivo800, keeping the overall dose nivolumab + nivo800 no more than 240 mg. Participants will undergo planned Standard of Care surgical resection at 1-4 days after infusion.