Trafficking of CAR T cells to sites of subclinical leukaemia cutis

A 45-year-old man with Philadelphia chromosome-positive B-cell acute lymphoblastic leukaemia that had relapsed following a matched sibling allograft was enrolled on a phase 1 CD19-targeting chimeric antigen receptor (CAR) study (NCT02893189) in April, 2017, at University College London (London, UK). This trial, called CAR19 Donor Lymphocytes for Relapsed CD19+ Malignancies following Allogeneic Transplantation (CARD), evaluates a second-generation allogeneic CD19 CAR (from the original bone marrow donor), administered in escalating doses analogous to a donor lymphocyte infusion regimen. The CAR, derived from a 4G7 hybridoma with a 4-1BB co-stimulatory domain, has a co-expressed suicide and marker gene (RQR8), detected by the anti-CD34 antibody, QBend10.