Abstract 1665: MuScreenTM : A well-characterized syngeneic model platform for rapid in vivo screening

Abstract

Abstract Background: Syngeneic tumor models, many shelved for decades, have been revived as effective models for immunotherapy, accompanying the clinical success of the immuno-checkpoint inhibitors (e.g. anti-CTLA4, anti-PD1, anti-PD-L1 antibodies). In vitro cell-based screens that are frequently used in oncology to quickly identify responsive cells and assess PD effects, often fail in immuno-oncology, due to immunotherapeutics targeting the complex host immune system. Alternatively, an in vivo screen with a panel of models addresses many of these questions, e.g. PD and efficacy, but may be cost prohibitive. Material and methods: Leveraging in-house detailed profiling data on our syngeneic models, including efficacy benchmarking with anti PD-1, PD-L1, CTLA-4, OX-40, GITR , LAG3 and TIM3 antibodies, RNAseq data on tumor samples, and FACS analysis on both baseline and post-treatment tumor samples, we created a new in vivo screening tool for immune-oncology: MuScreen. MuScreen includes up to 20 well-characterized syngeneic models in a 3 month screening run. Both PD and efficacy may be determined in the run, allowing researchers to make decisions based on results observed from a large dataset. To address the cost issue, test agents from multiple clients are pooled together for each run (sharing vehicle and other common groups) providing a significant reduction in the number of animals used and the associated costs. Results: CrownBio has established the largest collection of syngeneic models with well-characterized immunotherapy data. With the three MuScreen runs, we have generated new data on common IO agents (e.g. aPD-1 antibody) and combinations treatments, with FACS analysis, IHC, and efficacy data. Based on these data, a bioinformatics analyses were further explored to identify the makers/pathways that could be correlated with the efficacy or PD effect of the tested IO treatment. Conclusions: MuScreen, the first in vivo screening tool for cancer immunotherapeutics, provides detailed response data on a panel of syngeneic models, and may help on biomarker discovery in a cost and time efficient manner. Citation Format: Lan Zhang, Binchen Mao, Qian Shi. MuScreenTM : A well-characterized syngeneic model platform for rapid in vivo screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1665. doi:10.1158/1538-7445.AM2017-1665