Temozolomide, With or Without WSD0922-FU, for the Treatment of EGFR-Mutant, IDH-Wildtype Glioblastoma

Inclusion Criteria: * Age \>= 18 years * Histopathologic diagnosis of glioblastoma, IDH-wildtype \[as defined by the 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors\] on primary pathology review * NOTE: MGMT promoter methylation status must have been performed * Glioblastomas must have a pathogenic EGFR mutation, with or without EGFR amplification, detected by Clinical Laboratory Improvement Act (CLIA)-certified next-generation sequencing * EGFR mutation includes both deoxyribonucleic acid (DNA) sequence variants (e.g. point mutations, etc.) and transcript variants (e.g. EGFRvIII, etc.) * EXCEPTIONS: Glioblastomas which are EGFR wildtype with amplification are excluded. Glioblastomas which only have EGFR variants of unknown significance (without any pathogenic EGFR mutations) are also excluded * Patients must have completed standard radiation (60 Gy in 30 fractions) with concurrent temozolomide (missing no more than 2 weeks of temozolomide), and adequately recovered from treatment related toxicities * NOTE: Adjuvant temozolomide must not have been initiated * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2 * Hemoglobin \> 9.0 g/dL (obtained =\< 14 days prior to registration) * Leukocytes \> 3.0 x 10\^9/L (obtained =\< 14 days prior to registration) * Absolute neutrophil count (ANC) \> 1.5 x 10\^9/L (obtained =\< 14 days prior to registration) * Platelet count \> 100 x 10\^9/L (obtained =\< 14 d…