Optimized depletion of chimeric antigen receptor T cells in murine xenograft models of human acute myeloid leukemia

Blood. 2017 Apr 27;129(17):2395-2407. doi: 10.1182/blood-2016-08-736041. Epub 2017 Feb 28.

Abstract

We and others previously reported potent antileukemia efficacy of CD123-redirected chimeric antigen receptor (CAR) T cells in preclinical human acute myeloid leukemia (AML) models at the cost of severe hematologic toxicity. This observation raises concern for potential myeloablation in patients with AML treated with CD123-redirected CAR T cells and mandates novel approaches for toxicity mitigation. We hypothesized that CAR T-cell depletion with optimal timing after AML eradication would preserve leukemia remission and allow subsequent hematopoietic stem cell transplantation. To test this hypothesis, we compared 3 CAR T-cell termination strategies: (1) transiently active anti-CD123 messenger RNA-electroporated CART (RNA-CART123); (2) T-cell ablation with alemtuzumab after treatment with lentivirally transduced anti-CD123-4-1BB-CD3ζ T cells (CART123); and (3) T-cell ablation with rituximab after treatment with CD20-coexpressing CART123 (CART123-CD20). All approaches led to rapid leukemia elimination in murine xenograft models of human AML. Subsequent antibody-mediated depletion of CART123 or CART123-CD20 did not impair leukemia remission. Time-course studies demonstrated that durable leukemia remission required CAR T-cell persistence for 4 weeks prior to ablation. Upon CAR T-cell termination, we further demonstrated successful hematopoietic engraftment with a normal human donor to model allogeneic stem cell rescue. Results from these studies will facilitate development of T-cell depletion strategies to augment the feasibility of CAR T-cell therapy for patients with AML.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alemtuzumab
  • Animals
  • Antibodies, Monoclonal, Humanized / pharmacology
  • Antigens, CD20 / genetics
  • Antigens, CD20 / immunology
  • CD3 Complex / genetics
  • CD3 Complex / immunology
  • Female
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Hematopoietic Stem Cell Transplantation*
  • Humans
  • Immunotherapy, Adoptive / methods*
  • Interleukin-3 Receptor alpha Subunit / antagonists & inhibitors
  • Interleukin-3 Receptor alpha Subunit / genetics
  • Interleukin-3 Receptor alpha Subunit / immunology*
  • Lentivirus / genetics
  • Lentivirus / metabolism
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / immunology
  • Leukemia, Myeloid, Acute / pathology
  • Leukemia, Myeloid, Acute / therapy*
  • Lymphocyte Depletion
  • Male
  • Mice
  • Mice, Inbred NOD
  • RNA, Antisense / genetics
  • RNA, Antisense / immunology
  • RNA, Messenger / genetics
  • RNA, Messenger / immunology
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Remission Induction
  • Rituximab / pharmacology
  • T-Lymphocytes / cytology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / transplantation
  • Transplantation, Heterologous
  • Treatment Outcome
  • Tumor Necrosis Factor Receptor Superfamily, Member 9 / genetics
  • Tumor Necrosis Factor Receptor Superfamily, Member 9 / immunology
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Monoclonal, Humanized
  • Antigens, CD20
  • CD3 Complex
  • CD3 antigen, zeta chain
  • IL3RA protein, human
  • Interleukin-3 Receptor alpha Subunit
  • RNA, Antisense
  • RNA, Messenger
  • Receptors, Antigen, T-Cell
  • Recombinant Fusion Proteins
  • TNFRSF9 protein, human
  • Tumor Necrosis Factor Receptor Superfamily, Member 9
  • Alemtuzumab
  • Rituximab