Neoadjuvant LAG-3 Inhibitor + PD-1 Inhibitor in Children with Recurrent or Progressive High-Grade Glioma and Ependymoma

In this proposed study, we will expand on recent
data demonstrating that neoadjuvant PD-1 blockade improved survival among adult recurrent GBM patients by answering the following questions:
1) Does pre-surgical (neo-adjuvant) checkpoint inhibition serve as a primer to enhance the anti-tumor immune response in pediatric patients with recurrent malignant brain tumors
2) Can effective anti-tumor immune responses be generated and increased with the combination of two checkpoint inhibitors, LAG-3 and PD-1 antibody blockade if given pre-surgery followed by a maintenance regimen?
3) If immune response occurs, can we sensitively monitor that response using tumor biopsy tissue and peripheral blood immune cells?