Second generation CD19 CAR T-cells show exceptional efficacy in acute B-cell acute lymphoblastic leukemia (B-ALL), but it can be challenging to generate products from lymphopenic patients post allogeneic stem cell transplant (allo-SCT). Claire Roddie, MD, PhD, University College London, London, United Kingdom, discusses the rationale and results from the CARD study (NCT02893189). This phase I trial proposed the use of matched donor T-cells to overcome the challenges caused by patient lymphopenia. Dr Roddie reveals that this approach could come with a heightened risk of graft-versus-host disease (GvHD). However, results show that donor-derived matched allogeneic anti-CD19 CAR T-cells deliver excellent early remission rates in the absence of severe CAR-associated toxicity or GvHD. This interview took place at the American Society of Hematology (ASH) 2019 Annual Meeting and Exposition in Orlando, FL.