Project 1 proceeds from its demonstration during the last funding cycle that T cells targeting 5 tumor-expressed antigens (PRAME, SSX2, MAGEA4, NY-ESO-1, and Survivin - multiTAA T cells) can be used to effectively treat relapsed/refractory Hodgkin and non-Hodgkin lymphoma. Indeed, 5 of 9 patients with active disease achieved durable compete remissions when infused with multiTAA T cells, an outcome that correlated with the detection of tumor-reactive T cells in peripheral blood. This renewal proposal is designed to improve on these results by addressing two remaining barriers to successful cancer immunotherapy: (a) immune escape due to low target antigen expression and (b) the hostile tumor microenvironment, which can subvert the effector function and limit the persistence of infused T cells. To enhance target antigen expression on malignant cells, we will precondition patients with a DNA hypomethylating agent, 5-azacytidine, that upregulates tumor-associated antigens (TAAs) and then relate the biological effects of treatment to subsequent clinical responses (Aims 1 and 2). We predict that the increased target antigen expression on malignant cells will enhance their killing by the adoptively transferred T cells and lead to more effective recruitment and activation of endogenous cellular immune responses, resulting in epitope spreading that will potentiate the antitumor effects of the multiTAA T cells and thus the clinical benefit to patients. In addition, to convert the hostile tumor milieu into one that promotes rather than inhibits T-cell function, we will engineer our multiTAA T cells to express customized inverted cytokine receptors (ICRs) designed to interact with immunosuppressive tumor-derived molecules (TGF? and IL4) but deliver costimulatory and cytokine signals (4-1BB and IL7) that promote rather than inhibit T cell proliferation, activation, persistence and cytolytic activity (Aim 3). We predict that further benefit will derive from the sequestration of these suppressive tumor molecules, which would otherwise support tumor growth and survival while also polarizing the local environment towards inhibitory and tolerizing (Th2, Treg). Overall, we believe that these modifications will enable the wide introduction of a genuinely transformative cellular therapy for the treatment of relapsed/refractory lymphoma. This gain would not necessarily be limited to lymphoma; rather, the flexibility of the therapeutic strategy should enable the antigenic specificity of the engineered T cells to be tailored to each type of cancer under study.
We have developed a ?personalized? therapy for lymphoma that combines tumor-targeted immune cells (T cells) with a drug that sensitizes cancer cells to T cell killing. We believe that this novel approach will be safe and effective for high-risk lymphoma and ultimately for other cancers as well.
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