Two of the patients enrolled had tumors that harbored an IDH1 mutation and which would currently not be classified as GBM but as astrocytoma, IDH-mutant, WHO grade 4 based on the WHO 2021 classification of tumors of the CNS.23 This, however, did not affect the primary objective of this study which was safety and tolerability, and this study demonstrated the safety of combining Lisavanbulin and RT in newly diagnosed uGBM, up to the predefined dose level of Lisavanbulin 15 mg daily. Here, IDH1 is linked to glioblastoma.