Patient-derived organoids predict personalized drug response and reveal alternative therapeutic options in glioblastoma.

Glioblastoma remains a highly aggressive brain tumor with limited treatment options and poor prognosis. Temozolomide (TMZ) is the only approved first-line therapy, but frequent resistance limits its efficacy, highlighting the urgent need for alternative treatments. We establish 18 glioblastoma organoid (GBO) lines that preserve the histopathological and genomic features of the parental tumors, enabling comparison with clinical outcomes. GBO-based drug sensitivity testing (GBO-DST) showed a strong correlation with progression-free survival and outperformed O6-methylguanine-DNA methyltransferase (MGMT) methylation status in predicting TMZ response. Transcriptomic analysis reveals mechanisms of TMZ resistance, including mismatch repair deficiency, elevated MGMT expression, and upregulation of genes associated with axonogenesis and cell adhesion. Using GBO-DST, FDA-approved drug screening identifies regorafenib and lazertinib as effective treatment alternatives. Additionally, lazertinib demonstrated superior efficacy to standard therapies in GBO transplantation mouse model. These findings underscore the potential of GBO-DST as a robust platform for precision oncology in glioblastoma.