Abstract 4098: New strategy of drug response assessment using PDX organoid platform for non-resectable pancreatic cancer

To develop an efficient drug screening platform which overcomes the difference of drug response between initial screening and clinical trial stage is a pivotal issue for drug discovery. The patient-derived Xenograft (PDX) model has been reported as a screening system to reflect the microenvironment and heterogeneity of tumor. However, in pancreatic cancer that 80 % of patients is non-resectable, PDX is not be suitable for an initial screening model in terms of economic- and time cost of mouse-based amplification system as well as the lack of obtaining pancreatic tumor tissue from fine needle biopsy or percutaneous gun. To overcome this limitation, here we newly suggested organoids system, miniature organ culture on a dish, that are generated from tumor tissues of orthotopic PDX model, which has the advantages of reflection of each patient9s characteristics as well as amplification of limited tumor tissue. Besides, it is possible to screen of drug responsibility with a little number of cells. 12 organoids derived from PDX using needle or gun biopsy tumor tissues showed EpCAM overexpression and each unique morphological phenotype. Moreover, from drug responsibility test, H #43 and H #44, an organoids derived from a gemcitabine-sensitive patients, were highly responsible to gemcitabine, whereas the organoids from gemcitabine-resistant patients, G #20 and H #19 showed a strong resistance to gemcitabine as measuring the IC 50 value. In addition, combined treatment with gemcitabine and abraxane to the G #13 model which has no clinical information of drug response due to early death, it inhibited organoid formation significantly, showing a combination index below 1, which was proved through in vivo (PDX) validation. Taken together, the PDX-Organoid system might be able to reflect primary tumor characteristics as well as to overcome the quantitative limitations of the specimen and time cost, and thereby it is possible to predict drug response early in vitro, making it very efficient as an anti-cancer drug development platform for pancreatic cancer. Citation Format: A-Ra Jeon, Sun Il Choi, Sang-Jae Park, Sung-Sik Han, Sun-Young Kong, Min Kyeong Kim, Yu-sun Lee, Jieun Im, Min Kyeong Lee, Sang Hyun Park, Joon-Ki Kim, Kyong-Ah Yoon, Young-Hwan Koh, Ju Hee Lee, Woo Jin Lee, Sang Myung Woo, Yun-Hee Kim. New strategy of drug response assessment using PDX organoid platform for non-resectable pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4098.