CRISPR-edited CART with GM-CSF knockout and auto secretion of IL6 and IL1 blockers in patients with hematologic...

Revolutionary CART therapy still faces the challenge of severe cytokine release syndrome (CRS). While IL6 and IL1 have been demonstrated as essential contributors, GM-CSF is one of the most abundant inflammatory cytokines secreted by CART and has also been suggested in contributing to CRS. To minimize GM-CSF production from CART to reduce its associated toxicity, we conducted a pilot study (ChiCTR2000032124) of CRISPR-edited GM-CSF knockout (KO) in CART secreting anti-IL6 scFv and IL1RA, with additional TCR KO for tracing edited CART. The initial results of three patients (1 Non-Hodgkin lymphoma (NHL) and 2 multiple myelomas (MMs)) are summarized as: 3/3 complete response, 2/3 none CRS, 1/3 grade 2 CRS, and 0/3 neurotoxicity. The analysis revealed low levels of GM-CSF, IL6 and IL1B at the time of interferon-gamma (IFNG) peaks, and elevated IL1RA. We also observed significant expansion of CD3^- CART during treatment and no aberrant expansion of CD3^- CART in the follow-up. Re-expansion of CD3^- CART was observed in two patients while recurring CD19⁺ cells were eradicated in the patient with NHL. In summary, our study supported the safety and durable potency of CRISPR-edited CART in patients, providing a novel platform for developing autologous or allogeneic CART to minimize GM-CSF-associated toxicity in addition to autonomous IL6/IL1 blockade.