Abstract NTOC-078: ENGINEERING ADOPTIVE T CELL THERAPY FOR EFFICACY IN OVARIAN CANCER

Abstract

Abstract Over 20,000 women are diagnosed with ovarian cancer annually—more than half will die within 5 years and this rate has changed very little in the last 20 years, highlighting the need for innovative therapies. Reprogramming immune system cells to target and kill cancer cells represents a promising new treatment strategy. Immune T cells have the potential to control tumor growth without toxicity to healthy tissues when engineered to target proteins uniquely overexpressed in tumors. Recent technological advances have helped identify and validate Wilms' Tumor Antigen 1 (WT1) and mesothelin (MSLN) as valid antigen targets for ovarian cancer; these proteins contribute to malignant and invasive phenotypes and have limited expression in healthy cells. In preclinical studies using either patient-derived cell lines or the mouse ID8 ovarian tumor model, we show that T cells engineered to express either a WT1- or MSLN- specific high-affinity T cell receptor (TCR) can kill human and murine ovarian tumor cells in vitro. Moreover, in a disseminated in vivo murine model, adoptively transferred TCRengineered T cells preferentially accumulated within established ID8 tumors, delayed ovarian tumor growth, and prolonged mouse survival. However, our data also reveal that the tumor microenvironment (TME) limits the persistence and killing capacity of the engineered T cells. Cellular and molecular analyses of human tumor specimens show human therapy will face similar obstacles posed by the TME. Ongoing studies will be discussed that are exploring strategies to overcome elements common to the human and murine TME, including direct modulation of the environment and T cell engineering to promote T cell survival and function. Citation Format: Kristin G. Anderson, Breanna M. Bates, Edison Y. Chiu, Philip D. Greenberg. ENGINEERING ADOPTIVE T CELL THERAPY FOR EFFICACY IN OVARIAN CANCER [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr NTOC-078.