Abstract 5273: XenTech patient-derived xenograft (PDX) panels: a clinically relevant platform for drug efficacy, target validation and predictive biomarker discovery studies
Authors: Cairo Stefano , Déas Olivier , Legrier-Rahali Marie-Emmanuelle , Beurdeley Arnaud , Stephant Gaël , Poupon Marie-France , Judde Jean-Gabriel 
Published: August 2012

Abstract
Despite considerable efforts in understanding the biology and genetics of cancer, most currently available treatments fail to achieve tumor eradication in the majority of patients. Key to more effective therapies is adequate disease classification and subsequent patient stratification. In addition, it is important to understand the mechanisms of drug-response or resistance and identify novel targets amenable to therapeutic intervention. It is increasingly recognized that at the preclinical stage, testing therapeutic strategies and validating target relevance in more predictive models closely mimicking clinical disease such as patient derived xenografts (PDXs), may translate into improved clinical efficacy and lower rate of drug attrition. XenTech collection of over 120 runing PDX models is one of the largest in the world. PDX models were established by grafting post-surgery human tumor fragments in the interscapular region of immunodeficient mice. These deeply characterized PDX models can be used for in vivo preclinical assays. Such preclinical platform is a reliable surrogate of patient cohorts and can address several aims: 1. Evaluate tumor response to treatment. PDXs can be subjected to parallel evaluation of tumor response to various treatment protocols. Drug-response profile is linked to tumor histotype and molecular features in order to identify predictive markers of drug response to assist treatment choice. 2. Assess treatment-driven tumor eradication. The ability of a treatment to induce complete tumor response is assessed by monitoring tumor regression over a long period. Most tumors, despite complete macroscopic regression, are still present as latent microscopic nodular islands that may give rise to tumor recurrence. Molecular characterization of tumor foci responsible for tumor relapse may be performed to identify genes/pathways involved in residual tumor cell survival, which may provide new diagnostic and/or therapeutic targets for designing novel adjuvant treatment strategies. 3. Development of bioluminescent metastatic models to study the mechanisms of tumor invasion and to test anti-metastatic therapy. 4. Non-invasive molecular imaging technology to monitor tumor metabolism, vascularization and apoptosis. 5. Constitution of preclinical panels of rare malignancies to obtain phase II-like tumor cohorts. Development of new therapies for rare tumors is rendered difficult by the unavailability of patient cohorts wide enough to set up robust clinical trials. To assist the clinical need, these panels would allow the evaluation of new and more efficient therapies. We describe here in detail our PDX collection and illustrate how it represents a powerful tool to identify preferential therapeutic options for patients by exploring and improving anti-cancer therapeutic strategies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5273. doi:1538-7445.AM2012-5273