Donor-derived CARCIK-CD19 cells engineered with Sleeping Beauty transposon in acute lymphoblastic leukemia relapsed after allogeneic transplantation

Non-viral engineering can ease CAR-T cell production and reduce regulatory and cost requirements. We utilized Sleeping Beauty transposon to engineer donor-derived anti-CD19.CD28.OX40.CD3zeta T cells differentiated in cytokine-induced killer (CARCIK-CD19) for B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients relapsed after allogeneic hematopoietic stem cell transplantation (alloHSCT). We report the results of CARCIK-CD19 observed in 36 patients (4 children and 32 adults) treated according to the final recommended dose. Cytokine release syndrome of grade 2 or lower occurred in 15 patients, ICANS grade 2 in 1 patient, and late-onset peripheral neurotoxicity of grade 3 in 2 patients. GVHD never occurred after treatment with allogeneic CARCIK-CD19. Complete remission was achieved by 30 out of 36 patients (83.3%), with MRD negativity in 89% of responders. With a median follow-up of 2.2 years, the 1-year overall survival was 57.0%, and event-free survival was 32.0%. The median duration of response at 1 year was 38.6%. CAR-T cells expanded rapidly after infusion and remained detectable for over 2 years. Integration site analysis after infusion showed a high clonal diversity. These data demonstrated that SB-engineered CAR-T cells are safe and induce durable remission in heavily pretreated patients with BCP-ALL relapsed after alloHSCT. Trial registration: The phase 1/2 and phase II trials are registered at www.clinicaltrials.gov as NCT#03389035 and NCT#05252403.