Zhang, Hu, Yang et al. developed CRISPR–Cas9 based, gene-specific targeted CAR-T cells, integrating an anti-CD19 CAR sequence into the PD1 gene (PD1-19bbz), and demonstrated its safety and efficacy in a clinical trial. PD1-19bbz cells cleared tumor cells expressing either high or low levels of PD-L1 in coculture and xenograft models, potently eliminated tumor cells in patients with relapsed/refractory B cell-Hodgkin lymphoma without serious toxicity, and showed high rate (7/8) of complete and (6/8) durable response. Single-cell analysis showed that PD1-19bbz cells have an increased number of memory T cells and enhanced antitumor immune functions.
Contributed by Shishir Pant
ABSTRACT: Recently, chimeric antigen receptor (CAR)-T cell therapy has shown great promise in treating haematological malignancies(1-7). However, CAR-T cell therapy currently has several limitations(8-12). Here we successfully developed a two-in-one approach to generate non-viral, gene-specific targeted CAR-T cells through CRISPR-Cas9. Using the optimized protocol, we demonstrated feasibility in a preclinical study by inserting an anti-CD19 CAR cassette into the AAVS1 safe-harbour locus. Furthermore, an innovative type of anti-CD19 CAR-T cell with PD1 integration was developed and showed superior ability to eradicate tumour cells in xenograft models. In adoptive therapy for relapsed/refractory aggressive B cell non-Hodgkin lymphoma (ClinicalTrials.gov, NCT04213469 ), we observed a high rate (87.5%) of complete remission and durable responses without serious adverse events in eight patients. Notably, these enhanced CAR-T cells were effective even at a low infusion dose and with a low percentage of CAR(+) cells. Single-cell analysis showed that the electroporation method resulted in a high percentage of memory T cells in infusion products, and PD1 interference enhanced anti-tumour immune functions, further validating the advantages of non-viral, PD1-integrated CAR-T cells. Collectively, our results demonstrate the high safety and efficacy of non-viral, gene-specific integrated CAR-T cells, thus providing an innovative technology for CAR-T cell therapy.