Immune determinants of CAR-T cell expansion in solid tumor patients receiving GD2 CAR-T cell therapy.

Chimeric antigen receptor T cells (CAR-Ts) have remarkable efficacy in liquid tumors, but limited responses in solid tumors. We conducted a Phase I trial (NCT02107963) of GD2 CAR-Ts (GD2-CAR.OX40.28.z.iC9), demonstrating feasibility and safety of administration in children and young adults with osteosarcoma and neuroblastoma. Since CAR-T efficacy requires adequate CAR-T expansion, patients were grouped into good or poor expanders across dose levels. Patient samples were evaluated by multi-dimensional proteomic, transcriptomic, and epigenetic analyses. T cell assessments identified naive T cells in pre-treatment apheresis associated with good expansion, and exhausted T cells in CAR-T products with poor expansion. Myeloid cell assessment identified CXCR3 ⁺ monocytes in pre-treatment apheresis associated with good expansion. Longitudinal analysis of post-treatment samples identified increased CXCR3 ^- classical monocytes in all groups as CAR-T numbers waned. Together, our data uncover mediators of CAR-T biology and correlates of expansion that could be utilized to advance immunotherapies for solid tumor patients.
Competing Interests: Declaration of interests C.J.W. receives research funding from Pharmacyclics and hold equity in BioNTech, Inc. F.M. is a cofounder of and has equity in Harbinger Health, has equity in Zephyr AI, and serves as a consultant for Harbinger Health, Zephyr AI, and Red Cell Partners and Exscientia. F.M. declares that none of these relationships are directly or indirectly related to the content of this manuscript. E.S. consults for and holds equity in Lyell Immunopharma and consults for Lepton Pharmaceuticals and Galaria. M.S.M. is currently employed at Normunity and holds stock in AstraZeneca; her contributions to this work were made prior to these industry positions which are not relevant to the content of this manuscript. C.L.M. is an inventor on numerous patents and patents pending related to CAR-T cell therapies. C.L.M. holds equity in and receives research funding from Lyell Immunopharma and holds equity in and consults for CARGO Therapeutics and Link Cell Therapies. C.L.M. consults for Immatics, Mammoth, Ensoma, and Red Tree Venture Capital.
(Published by Elsevier Inc.)