Fig. 3: Low-dose chemotherapy enhances anti-tumor efficacy of Le^Y CAR T cells in vivo.

a Tumor volume (mean ± SEM) of PDX-287R grafts following treatment with no T cell control (n = 21 grafts), Le^Y CAR T cells (n = 17 grafts) or control empty vector T (ev-T; n = 17 grafts) cells alone. Data from three independent experiments. b Tumor volume (mean ± SEM) of PDX-287R grafts following treatment with no T cell control (n = 15 grafts), Le^Y CAR T cells (n = 12 grafts), ev-T cells (n = 12 grafts), nivolumab (200 µg/dose, 4 doses, n = 13 grafts), and nivolumab with Le^Y CAR T cells (n = 8 grafts). Data from two independent experiments. c Tumor volume (mean ± SEM) of PDX-287R grafts following treatment with no T cell control (n = 6 grafts), Le^Y CAR T cells (n = 5 grafts), ev-T cells (n = 5 grafts), docetaxel (10 mg/kg, 1 dose; n = 6 grafts) and docetaxel with Le^Y CAR T cells (n = 6 grafts). Data from 1 experiment. d Tumor volume (mean ± SEM) of PDX-287R grafts following treatment with no T cell control (n = 15 grafts), Le^Y CAR T cells (n = 12 grafts), ev-T cells (n = 12 grafts), carboplatin (50 mg/kg, 1 dose; n = 17 grafts), and carboplatin with Le^Y CAR T cells (n = 10 grafts). Data from two independent experiments. e Representative PDX-287R grafts after treatment with ev-T cells (n = 12 grafts), CAR T cells (n = 12 grafts), carboplatin (carbo; n = 17 grafts), and carboplatin with CAR T cells (carbo + CAR T cells; n = 10 grafts). f Quantification of pHH3 immunohistochemistry in PDX-287R grafts 5–6 weeks post-treatment with no T cell control (n = 8 grafts), carboplatin (n = 4 grafts), docetaxel (DTX; n = 5 grafts), nivolumab (n = 6 grafts), ev-T cells (n = 6 grafts), CAR T cells (n = 7 grafts), nivolumab (nivo) + CAR T cells (n = 6 grafts), carbo + CAR T cells (n = 4 grafts), and DTX + CAR T cells (n = 3 grafts). Statistical significance determined by one-way ANOVA with post-hoc Tukey’s test. g Tumor volume (mean ± SEM) of PDX-224R-Cx grafts following treatment with no T cell control (n = 12 grafts), Le^Y CAR T cells (n = 6 grafts), ev-T cells (n = 8 grafts), carboplatin (50 mg/kg, 1 dose; n = 14 grafts), carboplatin with Le^Y CAR T cells (n = 6 grafts), and carboplatin with ev-T cells (n = 9 grafts). Data from two independent experiments. Compared to PDX-287R, PDX-224R-Cx had decreased sensitivity to carboplatin treatment alone, and a reduced response to carboplatin-CAR T cell combination treatment. Significance was determined by linear mixed model analysis at end of treatment with a test of simple main effects to compare between treatment groups: a CAR T cells vs carboplatin + CAR T cells, p = 0.015; b carboplatin + ev-T cells vs carboplatin + CAR T cells, p = 0.044; c no T cells vs carboplatin + CAR T cells, p = 0.008; d carboplatin vs carboplatin + CAR T cells, p = 0.028. Source data are provided as a Source Data file.