Abstract
BACKGROUND: Chimeric antigen receptor (CAR) T cell therapy is a promising treatment for central nervous system (CNS) tumors like diffuse intrinsic pontine glioma (DIPG) and diffuse midline glioma (DMG). Unlike systemic administration, locoregional CAR T therapy may result in tumor inflammation-associated neurotoxicity (TIAN), which was recently defined. This study retrospectively applies TIAN criteria to patients with DIPG/pontine DMG treated with intraventricular B7-H3 CAR T cells in the BrainChild-03 (BC-03) trial (NCT04185038). METHODS: A retrospective analysis of DIPG/pontine DMG patients treated with locoregional B7-H3 CAR T cells in BC-03 was conducted. Neurological symptoms, headache, fever, hydrocephalus, and inflammatory markers were extracted from case reports and medical records. TIAN was classified as type 1 (mechanical damage) or type 2 (electrophysiologic dysfunction), and symptom patterns, resolution, imaging findings, and management were analyzed. RESULTS: Among 21 patients (ages 2-22) receiving ≥1 infusion, 16 (76%) met TIAN criteria at least once. TIAN occurred in 49 of 152 infusions (32%), mostly grade 1 (n = 34) or grade 2 (n = 14), with one grade 3 event. Common symptoms included headache with fever (51%) and neurologic changes with headache (31%). In most patients, Type 1 vs Type 2 TIAN could not be defined; however, 1 patient required CSF diversion (type 1 TIAN), and 13 had worsening preexisting deficits (type 2). Median symptom resolution was <24 h (range: 0-33). CONCLUSIONS: TIAN was common within this cohort but mostly low-grade and transient. Refining its classification and understanding its clinical impact will aid safety assessments and trial comparisons for CNS-directed CAR T therapies.