Ex Vivo Tumor-Derived Organoid Pharmacotyping Identifies Personalized Therapeutic Options for Patients with Biliary Tract Cancer

Biliary tract cancers (BTC) pose clinical challenges due to poor chemotherapy response and aggressive disease course. We evaluated patient-derived tumor organoid-based drug sensitivity testing as a tool to guide therapy. In this multicenter study, 26 tumor organoids were successfully derived from 43 patients with BTC and tested with an average of 50 cancer-directed therapies using the Clinical Laboratory Improvement Amendments-certified PARIS assay. Despite most organoids being from late-stage disease, 24/26 (92.3%) exhibited strong sensitivity to one or more targeted agents. Active drugs included inhibitors of EGFR/HER2, MEK, ERK, BCR-ABL and SRC family, mTOR, PI3K, MDM2, BCL2, and BET. Drug sensitivities aligned with known genetic biomarkers but were also observed in cultures lacking them, indicating ex vivo testing can expand actionability beyond genomics. In five cases, results guided therapy; one patient with an FGFR-BICC1 fusion refractory to FGFR inhibitors responded to dasatinib, achieving symptomatic improvement, stable disease, and >8-month survival.

Significance
Ex vivo drug testing of tumor-derived organoids is clinically feasible and can be used to identify personalized treatment options for patients with BTC, to evaluate the functional relevance of genomic biomarkers, and to guide treatment in real time.