Abstract Patient-derived xenograft (PDX) models have been established from the world's largest living tumor bank at Molecular Response and used to mimic clinical trial settings with patients with heterogeneous populations and heterogeneous disease within oncology indications for a faster and less expensive path to test novel compounds in a more predictive preclinical setting. Overall, the collection is comprised of 144 000 tumor samples corresponding to 70 000 unique patients and continues to grow with new patient samples added routinely. For several patients, multiple samples were collected at different times (before and after treatment) or at different locations (primary/ metastatic). This allows evaluation of drug efficiency in pre and post treatment application which mimics a clinical setting as well the ability to monitor the effect of drug on the primary tumor and a matched metastatic tumor. For banked tumors, we have histo-pathological and molecular data as well as FFPE slides, DNA, RNA and chemosensitivity data from the original patient. MRL currently has over 350 PDX models in progress and has established >300 unique PDX models in multiple indications. Many established PDX models have confirmed histology and mutational profiling (Next-Gen sequencing) to demonstrate preservation of the biological characteristics of these models to the original patient sample as well as between passages within the model. MRL's vast collection of patient samples allows clients the ability to focus on unique subsets of patients for a custom model build or the ability to choose from our extensive list of established PDX models to further drug discovery of novel compounds. Citation Format: Thomas Broudy, Jill Ricono, Colleen Scott, Praveen Nair, Jayant Thatte, Cyrus Mirsaidi. Molecular Response LLC tumor bank and patient-derived tumor xenograft models: a powerful translational engine for discovery and development of novel oncology therapeutics. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3224. doi:10.1158/1538-7445.AM2015-3224