EXTH-53. THE PHARMACOLOGICAL ATLAS OF MENINGIOMAS

Abstract No systemic treatment options exist for recurrent or refractory meningioma patients. This study aimed to create a pharmacological atlas of all FDA-approved oncology drugs in a large cohort of patient-derived meningioma organoids (TOs). TOs were generated from single cell suspensions from freshly resected meningiomas and were treated with semi-logarithmic concentrations spanning from 10 nM to 30 µM by the automated liquid handler Hamilton MicroLAB STAR®. The drug library AODX from the National Cancer Institute consisted of 179 FDA-approved anticancer drugs. The viability was measured with the RealTimeGlo (Promega). Half-maximal inhibitory concentrations (IC50) were calculated by GraphPad Prism software. We created a pharmacological atlas of meningiomas by generating 8,413 dose-response curves of 179 current FDA-approved oncology drugs in patient-derived tumor organoids from 47 meningioma patients. The cohort consisted of 35 grade 1, 11 grade 2, and 1 grade 3 meningiomas, including 10 recurrent tumors. In total, 21% (n=39/179) of the drugs exhibited sensitivity (median IC50 < 30 µM), with significant enrichment for topoisomerase, RNA/protein synthesis, proteasome, and HDAC inhibitors. The top five drugs with the lowest IC50 values were romidepsin, dactinomycin, carfilzomib, plicamycin, and omacetaxine with median values of 10, 31, 145, 303, and 400 nM. Hierarchical clustering of IC50 data revealed at least two distinct drug response clusters defined by sensitivity to tyrosine kinase inhibitors. When considering the Cmax/IC50 ratio as a potential predictive marker of treatment response (>1), the HDAC inhibitors belinostat (74.5), romidepsin (69.7), the proteasome inhibitor carfilzomib (34.6), and the anthracyclines epirubicin (2.6), and doxorubicin (1.8), and the PI3K inhibitor idelalisib (1.6) are the most promising drug candidates for further in vivo evaluation. We provide the first comprehensive insight into the pharmacological landscape of meningiomas. This data might serve as the foundation for future clinical studies on the systemic treatment of aggressive meningiomas.