Phase I study of CAR-T cells with PD-1 and TCR disruption in mesothelin-positive solid tumors

Cell Mol Immunol. 2021 Sep;18(9):2188-2198. doi: 10.1038/s41423-021-00749-x. Epub 2021 Aug 11.


Programmed cell death protein-1 (PD-1)-mediated immunosuppression has been proposed to contribute to the limited clinical efficacy of chimeric antigen receptor T (CAR-T) cells in solid tumors. We generated PD-1 and T cell receptor (TCR) deficient mesothelin-specific CAR-T (MPTK-CAR-T) cells using CRISPR-Cas9 technology and evaluated them in a dose-escalation study. A total of 15 patients received one or more infusions of MPTK-CAR-T cells without prior lymphodepletion. No dose-limiting toxicity or unexpected adverse events were observed in any of the 15 patients. The best overall response was stable disease (2/15 patients). Circulating MPTK-CAR-T cells peaked at days 7-14 and became undetectable beyond 1 month. TCR-positive CAR-T cells rather than TCR-negative CAR-T cells were predominantly detected in effusion or peripheral blood from three patients after infusion. We further confirmed the reduced persistence of TCR-deficient CAR-T cells in animal models. Our results establish the preliminary feasibility and safety of CRISPR-engineered CAR-T cells with PD-1 disruption and suggest that the natural TCR plays an important role in the persistence of CAR-T cells when treating solid tumors.

Keywords: CAR-T; CRISPR-Cas9; Mesothelin; PD-1; TCR.

Publication types

  • Clinical Trial, Phase I
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Humans
  • Immunotherapy, Adoptive / adverse effects
  • Immunotherapy, Adoptive / methods
  • Mesothelin
  • Neoplasms*
  • Programmed Cell Death 1 Receptor / metabolism
  • Receptors, Antigen, T-Cell / metabolism
  • Receptors, Chimeric Antigen* / genetics
  • Receptors, Chimeric Antigen* / metabolism
  • T-Lymphocytes


  • Programmed Cell Death 1 Receptor
  • Receptors, Antigen, T-Cell
  • Receptors, Chimeric Antigen
  • Mesothelin