Expanded ATLAS (TM)-identified neoantigen-specific peripheral T cells (NPTs) demonstrate considerable neoantigen breadth, polyfunctionality, and effector function

Abstract Adoptive T cell therapy using ex vivo expanded autologous tumor-infiltrating lymphocytes (TIL) has resulted in notable tumor regression across multiple solid tumor indications. Despite their success, TIL harvest requires invasive surgery and sterile isolation. In addition, extracted cells from an immunosuppressive tumor microenvironment (TME) often have impaired functions, low neoantigen-specificity and require high dose cytokine for expansion. All possible reasons for non-responders or post-treatment relapse. Generating T cell therapies specifically expanded against neoantigen targets and derived from peripheral blood lymphocytes may overcome these limitations. The ATLAS bioassay identifies patient-specific neoantigen targets of T cells, and Inhibigens™, tumor antigens that are detrimental to protective immune responses. Using PLANET™, a robust and scalable closed manufacturing process, T cells specific for up to 30 ATLAS-identified neoantigens (excluding Inhibigens) are expanded, providing considerable breadth of tumor recognition and the potential to limit tumor escape. Use of peripheral T cells leverages robust cells not suppressed by the TME and eliminates the need for invasive tumor resection. Our data show that NPTs are specific for up to 89% of targeted neoantigens, consist of non-exhausted effector and central memory cells, and express proliferative and tissue homing markers. NPTs are highly polyfunctional, secreting multiple combinations of IFNγ, Granzyme B, TNFα, and MIP1α in response to specific neoantigens. Evaluation of markers for memory-progenitor stem-like features in NPTs are being explored and will be discussed. The TITAN™ clinical trial evaluating GEN-011 NPTs is ongoing (NCT04596033).