Related Experiment Video
Updated: Oct 25, 2025
Generation and Expansion of Primary, Malignant Pleural Mesothelioma Tumor Lines
Published on: April 21, 2022
Phase I study of CAR-T cells with PD-1 and TCR disruption in mesothelin-positive solid tumors
Zhenguang Wang1,2, Na Li3, Kaichao Feng2
1Medical School of Chinese PLA, Beijing, China.
Abstract:
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.
Insights
Engineered chimeric antigen receptor T (CAR-T) cells lacking PD-1 and T cell receptor (TCR) show preliminary safety for solid tumors. TCR-positive CAR-T cells demonstrated better persistence, suggesting a role for the natural TCR in CAR-T cell efficacy.
Area of Science:
- Immunotherapy
- Oncology
- Gene Editing
Background:
- Programmed cell death protein-1 (PD-1) mediated immunosuppression limits chimeric antigen receptor T (CAR-T) cell efficacy in solid tumors.
- Chimeric antigen receptor T cells are a promising cancer therapy, but their effectiveness in solid tumors is often hindered by the tumor microenvironment.
Purpose of the Study:
- To assess the safety and feasibility of genetically engineered mesothelin-specific CAR-T cells (MPTK-CAR-T) deficient in both PD-1 and the endogenous T cell receptor (TCR).
- To investigate the role of the natural TCR in the persistence and efficacy of CAR-T cells in patients with solid tumors.
Main Methods:
- CRISPR-Cas9 gene editing was used to generate PD-1 and TCR deficient MPTK-CAR-T cells.
- A dose-escalation study was conducted in 15 patients with solid tumors who received MPTK-CAR-T cell infusions without lymphodepletion.
- Patient samples and animal models were used to evaluate CAR-T cell persistence and characteristics post-infusion.
Main Results:
- No dose-limiting toxicities or unexpected adverse events were observed in the 15 patients treated with MPTK-CAR-T cells.
- The best overall response observed was stable disease in 2 out of 15 patients.
- TCR-positive MPTK-CAR-T cells showed predominant detection in patient samples and better persistence compared to TCR-deficient counterparts, as confirmed in animal models.
Conclusions:
- CRISPR-engineered CAR-T cells with PD-1 disruption are preliminarily feasible and safe for treating solid tumors.
- The natural TCR appears to play a crucial role in the in vivo persistence of CAR-T cells, particularly in the context of solid tumor treatment.
- Further research is warranted to optimize CAR-T cell design for enhanced persistence and therapeutic outcomes in solid tumors.
