Multimodality mapping of immunotherapy distribution as a predictive marker in glioma

BACKGROUND: Scarce T cell infiltration, immunosuppressive tumor-associated macrophages, and ineffective drug delivery drive glioma progression and limit treatment efficacy. Mapping immunotherapy distribution by multimodality imaging might be a biomarker that could aid tumor monitoring and guide therapy development. METHODS: To assess drug delivery, we developed a MRI-lightsheet microscopy platform (MR-LSM) to monitor immunotherapy at the cellular level in two immunocompetent glioma models (Gl261, SB28). The atezolizumab (PD-L1 inhibitor) subgroup of the multicenter N2M2/NOA20 trial in MGMT unmethylated GBM patients was assessed by CNN analysis and correlated to progression-free survival. RESULTS: In contrast to the conventional Gl261 glioma model, SB28 gliomas are characterized by poor immunogenicity and resistance to Toll-like receptor (TLR) 7 targeted therapy delivered by CDNP-R848 nanoparticles. SB28 resistance is driven by microvascular pathology, vasogenic edema, and drug off-targeting to peritumoral edema and white matter tracts. Vascular endothelial growth factor (VEGF) inhibition in conjunction with irradiation and dual immunotherapy (DIR) targeting innate (CDNP-R848) and adaptive immunity (anti-CTLA-4) breaks resistance, increases survival, and reverses drug off-targeting. Mechanistically, tumor control is orchestrated by vascular normalization, enhanced CD8+ T cell influx, and a proinflammatory shift of myeloid cells along with strong IL-12/IL-13 upregulation. In a translational analysis of the multicenter N2M2/NOA20 trial, we validate that edema and microvascular pathology are associated with poor prognosis in glioblastoma patients treated with checkpoint immunotherapy and that patients without edema have increased PFS. CONCLUSIONS: . We develop a customizable imaging platform to map drug delivery to glioma with broad applicability in neuroscience and neuro-oncology.