Peripheral blood derived PD-1/CD28-CD19 CAR modified PD-1+ T cell therapy in patients with solid tumors

T cells with PD-1 expression in peripheral blood (PB) of patients with tumors have therapeutic potential, but the immunosuppressive signaling pathway and limited proliferative capacity of PD-1+ T cell-based therapy in vivo pose challenges to their application. Here, we first showed that no discernible distinction was observed between PD-1+ and PD-1- T cells in terms of clonal overlap. However, CD8+PD-1+ T cells from PB and tumor tissues exhibited tighter clustering based on clone size. Interestingly, PD-1+ T cells in blood highly expressed cytotoxicity-related genes and enriched T cell activation-related pathways than PD-1- T cells from PB or tumor tissues using single-cell RNA sequencing. Meanwhile, PB-derived PD-1+ T cells exhibited strong cytotoxicity towards autologous tumor cells or tumor cell line. To further augment the PD-1+ T cell activity against solid tumors in vivo, we introduced a PD-1/CD28 fusion receptor combined with CD19 chimeric antigen receptor (CAR) into PD-1+ T cells, which were expanded in vitro. We found the modified PD-1+ T cells exhibited superior proliferation and anti-tumor abilities in vitro. Notably, four patients with cancer were enrolled and received autologous PD-1/CD28-CD19 CAR-PD-1+ T cells infusion, and none of these patients experienced severe side effects. We also observed that one patient with melanoma achieved a complete response and maintained 6.7 months. Three other patients with cancer had stable disease. Collectively, these results suggested that cell therapy with modified PB-derived PD-1+ T cells is both safe and effective, and may constitute a promising treatment strategy for cancer patients.