Testing the Anti-cancer Drug Erdafitinib for Brain Cancers That Have Returned or Progressed Following Treatment

Inclusion Criteria: * Patient must be \>= 18 years of age * Patient must have histologically confirmed IDH-WT gliomas (grade 2-4) as per World Health Organization (WHO) 2016 or 2021 classification * Tumor tissue should be positive for FGFR-TACC gene fusion as per any local next generation sequencing (NGS) (Clinical Laboratory Improvement Act \[CLIA\]-approved) assay described in background section * The disease should be recurrent or progressive glioma after initial anti-tumor treatment with at least 1 line of treatment including surgical resection, radiation therapy and/or chemotherapy * For patients with WHO grade 3 or 4 glioma and progressive disease \< 12 weeks after completion of chemoradiotherapy, progression can be defined by the following set of criteria: * New enhancement outside of the radiation field (beyond the high-dose region or 80% isodose line) * If there is unequivocal evidence of viable tumor on histopathologic sampling (e.g., solid tumor areas. i.e., \> 70% tumor cell nuclei in areas), high or progressive increase in Ki-67 proliferation index compared with prior biopsy, or evidence for histologic progression or increased anaplasia in tumor) * For patients with WHO grade 3 or 4 glioma and progressive disease \>= 12 weeks after completion of chemoradiotherapy, progression can be defined by the following set of criteria: * New contrast-enhancing lesion outside of radiation field on decreasing, stable, or increasing doses of corticosteroids * Increas…