Pharmacokinetic and pharmacodynamic studies of CD19 CAR T cell in human leukaemic xenograft models with dual‐modality imaging

In recent years, chimeric antigen receptor T (CAR T)‐cell therapy has shown great potential in treating haematologic disease, but no breakthrough has been achieved in solid tumours. In order to clarify the antitumour mechanism of CAR T cell in solid tumours, the pharmacokinetic (PK) and pharmacodynamic (PD) investigations of CD19 CAR T cell were performed in human leukaemic xenograft mouse models. For PK investigation, we radiolabelled CD19 CAR T cell with (89)Zr and used PET imaging in the CD19‐positive and the CD19‐negative K562‐luc animal models. For PD evaluation, optical imaging, tumour volume measurement and DNA copy‐number detection were performed. Unfortunately, the qPCR results of the DNA copy number in the blood were below the detection limit. The tumour‐specific uptake was higher in the CD19‐positive model than in the CD19‐negative model, and this was consistent with the PD results. The preliminary PK and PD studies of CD19 CAR T cell in solid tumours are instructive. Considering the less efficiency of CAR T‐cell therapy of solid tumours with the limited number of CAR T cells entering the interior of solid tumours, this study is suggestive for the subsequent CAR T‐cell design and evaluation of solid tumour therapy.