Mitigation of chromosome loss in clinical CRISPR-Cas9-engineered T cells

Cell. 2023 Oct 12;186(21):4567-4582.e20. doi: 10.1016/j.cell.2023.08.041. Epub 2023 Oct 3.


CRISPR-Cas9 genome editing has enabled advanced T cell therapies, but occasional loss of the targeted chromosome remains a safety concern. To investigate whether Cas9-induced chromosome loss is a universal phenomenon and evaluate its clinical significance, we conducted a systematic analysis in primary human T cells. Arrayed and pooled CRISPR screens revealed that chromosome loss was generalizable across the genome and resulted in partial and entire loss of the targeted chromosome, including in preclinical chimeric antigen receptor T cells. T cells with chromosome loss persisted for weeks in culture, implying the potential to interfere with clinical use. A modified cell manufacturing process, employed in our first-in-human clinical trial of Cas9-engineered T cells (NCT03399448), reduced chromosome loss while largely preserving genome editing efficacy. Expression of p53 correlated with protection from chromosome loss observed in this protocol, suggesting both a mechanism and strategy for T cell engineering that mitigates this genotoxicity in the clinic.

Keywords: CAR T cells; CRISPR screen; CRISPR-Cas9; DNA repair; T cells; aneuploidy; chromosome loss; clinical trial; genome editing; immunoengineering.

Publication types

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

MeSH terms

  • CRISPR-Cas Systems* / genetics
  • Chromosome Aberrations*
  • Chromosomes
  • Clinical Trials as Topic
  • DNA Damage
  • Gene Editing* / methods
  • Humans
  • T-Lymphocytes*

Associated data