IDH1 and central nervous system cancer: Some of these vaccines are being investigated in phase I clinical trials in gliomas, for example, the NOA21 trial (ClinicalTrials.gov ID: NCT03893903) aims at assessing the safety and immunogenicity of IDH1-vac in combination with the programmed death-ligand 1 (PD-L1)-blocking immune checkpoint inhibitor avelumab in gliomas [29].