RecruitingEarly Phase 1Drug trialA Phase 0/1 Study of BDTX-1535 in Recurrent High-Grade Glioma (rHGG) and Newly Diagnosed Glioblastoma (nGBM) Participants With EGFR Alterations or FusionsThis study will administer the investigational drug, BDTX-1535 to eligible patients with recurrent high-grade glioma (HGG) and newly-diagnosed glioblastoma (nGBM). BDTX-1535 was designed to block a growth signal important to some cancers. BDTX-1535 is being tested in this study to see if it can be given safely to people who have tumors that can be dependent on that growth signal because of changes in a protein called EGFR. These gene changes are called amplifications, mutations, fusions or alterations and are found only in the tumors. The study design includes a Phase 0 component with PK/PD-trigger for participant enrollment into an Expansion Phase 1 component. The primary objective of the Phase 0 component is to evaluate the PK endpoints of BDTX-1535. The primary objective of the Phase 1 component is to establish the safe dose of BDTX-1535 to be used in participants with a specified treatment regimen, three of which include standard of care radiotherapy for nGBM participants.