Abstract IA02: Engineering T cells to eradicate tumors in the age of synthetic biology

• Published in: Cancer immunology research 2018-09, Vol.6 (9_Supplement), p.IA02-IA02
• Main Authors: Greenberg, Philip D., Anderson, Kristin G., Egan, Dan, Hingorani, Sunil R., Oda, Shannon K., Perret, Rachel, Schmitt, Tom M., Stromnes, Ingunn M., Schmidt, Leah, Chapuis, Aude G.
• Format: Article
• Language: English
• ISSN: 2326-6066; 2326-6074
• DOI: 10.1158/2326-6074.TUMIMM17-IA02

Unlike cancer vaccines and immune modulators such as checkpoint inhibitors that seek to harness patient immune responses, adoptive therapy with genetically engineered T cells seeks to create responses that don’t exist in the patient’s immune system. Molecular technologies now make it feasible to not only create T cells with specificity for the tumor by introduction of a selected antigen-specific receptor, but also with qualities not naturally found, including improved function and resistance to immunosuppression. We have been exploring in preclinical models and clinical trials methods to reproducibly provide therapeutic T cell responses by transfer of genetically engineered T cells. For human acute myelogenous leukemia (AML), we have pursued targeting WT1, a gene overexpressed in human leukemic stem cells that is associated with promoting leukemic transformation. Preclinical studies performed in a mouse model demonstrated that CD8 T cells expressing a high affinity TCR specific for this oncogene can be safely administered, with no evidence of toxicity to the normal tissues known to express low but detectable levels of WT1. We have advanced this approach to a clinical trial in leukemia patients with poor prognostic factors that place them at high risk of relapse after hematopoietic cell transplant (HCT), using a high-affinity human TCR specific for WT1 to transduce CD8 cells and reproducibly create high-avidity T cells that recognize leukemic cells. Our clinical results demonstrate that such T cells can prevent leukemic relapse and sustain long-term remissions, and can mediate antileukemic activity in patients who have relapsed. This therapy is now being tested in AML patients who have minimal residual disease after induction therapy and are not candidates for HCT, as well as in solid tumors that similarly overexpress WT1. Unfortunately, there are substantive obstacles in targeting established tumors that can preclude even a T cell expressing a high-affinity TCR from being effective. These impediments include the development of T cell dysfunction, particularly within the microenvironment of solid tumors, and we are using genetically engineered mouse models to elucidate the cellular and molecular pathways that need to be modulated to achieve meaningful therapeutic benefit in a variety of hematologic and solid tumor settings, including pancreatic and ovarian cancer. Our preclinical therapy studies reveal promising antitumor activity, but demonstrate that repe