Abstract A60: GM-CSF modulation restricts the secretion of main cytokines associated with CAR T-cell induced cytokine release syndrome

Emerging CAR T-cell therapies have shown high remission rates in patients with hematologic malignancies. Despite the success of these novel immunotherapies, multiple adverse effects are associated with CAR T-cell infusions. Cytokine release syndrome (CRS) is one of the most common CAR T cell-associated toxicities and results from the rapid elevation of inflammatory cytokines, which can be life threatening. CRS is commonly managed in the clinic with anti-IL-6R antibodies and glucocorticoids. While efficacious, these treatments address CRS only after it has initiated; therefore, alternative therapeutic strategies preventing CRS onset remain an urgent need. Using cytokine profiling arrays, we identified that secreted granulocyte macrophage colony stimulating factor (GM-CSF) contributes to CRS, since elevated GM-CSF levels promote macrophage-dependent secretion of key CRS biomarkers including MCP-1, IL-6, and IL-8. Modulation of GM-CSF levels either via genetic engineering of CAR T-cells using TALEN® technology or via neutralizing-antibodies resulted in a marked reduction of macrophage-dependent release of CRS-associated cytokines, while preserving antitumor activity. Our work proposes a novel therapeutic strategy to improve the overall safety of CAR T-cell therapies in cancer patients by using GM-CSF knockout CAR T cells. Citation Format: Mohit Sachdeva, Beatriz Aranda-Orgilles, Philippe Duchateau, Laurent Poirot, Julien Valton. GM-CSF modulation restricts the secretion of main cytokines associated with CAR T-cell induced cytokine release syndrome [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A60.