Abstract 198: Pan-cancer assay-ready organoid drug screening with robust, reproducible and clinically-relevant output
Authors: Wijler Liza , Mateos Jara Garcia , Nguyen My , Staes Annelot , van Seters Linda , Hasan Lama Alhaj , Tiroille Victor , Herpers Bram , Price Leo , Madej Mariusz , Fokkelman Michiel , Putker Marrit 
Published: April 2023

Abstract
Introduction The pharmaceutical industry has mostly relied on 2D cancer cell lines and 3D spheroids for in vitro testing, but poor correlation of pre-clinical and clinical outcomes has driven the development of more predictive models. Patient-derived organoids (PDOs) have emerged as representative in vitro avatars of tumor biology, allowing the generation of biobanks covering a large variety in indications and genetic backgrounds. Here, we assess the robustness of our drug screening platform by testing the reproducibility of our organoid assays within and between organoid batches, read-outs, and different labs. We present an assay-ready organoid platform, allowing short timelines, repeated assays from a single batch of organoids, high throughput assays and large panel screens.
Methods Colorectal, breast, lung, pancreatic, ovarian, cervix and melanoma PDO models were selected for subtype and driver mutation variety, banked in large batches, and preserved in assay-ready format. Outgrowth and drug responses of these batches were compared to those of organoids produced in the classic method. Experiments were executed using automated liquid handling equipment to standardize procedures and increase consistency. Performance of the drug screens were assessed by repeated drug sensitivity testing and by calculating intra- and interplate variability, control variability (CV), Z-factor, assay windows and IC50 values. Moreover, drug responses were tested in both celltiterglo-based and high content imaging-based assays.
Results Assay performance of the organoid drug testing platform was high, with high Z-factors (&gt;0.6), and low intra- and interplate variability (CV &lt;15%) indicating reproducible assays. Both the classic and assay-ready organoid technologies resulted in highly reproducible IC50outputs, also when assays were executed months apart or in different labs. Timelines were shortened from months to weeks, and the reduced logistical burden allows screening of large organoid panels of &gt;50 models. Drug sensitivity testing in our fast-paced panel screening platform distinguished sensitive from partially and insensitive models, illustrating how organoids allow patient stratification.
Conclusion and Discussion The assay-ready organoid technology presented here has further improved our already highly predictive and reproducible organoid drug testing platform. The resulting short timelines and large panel screening capabilities will further unlock the great potential of PDO technology. Using large organoid panels in pre-clinical drug development and in combination with biomarker analysis will allow identification of responsive indications, subtypes, and genotypes, and for early patient stratification. Moreover, as most models presented in our panel screen platform are also available as PDX models, it allows for easy translation into in vivo follow-up studies.
Citation Format: Liza Wijler, Jara Garcia Mateos, My Nguyen, Annelot Staes, Linda van Seters, Lama Alhaj Hasan, Victor Tiroille, Bram Herpers, Leo Price, Mariusz Madej, Michiel Fokkelman, Marrit Putker. Pan-cancer assay-ready organoid drug screening with robust, reproducible and clinically-relevant output [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 198.