CLL-1/CD70 Dual-Target CAR-T Cell Therapy for Acute Myeloid Leukemia

This is a single-center, open-label, single-arm, prospective, investigator-initiated dose-escalation study to evaluate the safety, tolerability, and preliminary efficacy of an autologous CLL-1/CD70 dual-target CAR-T cell injection in patients with relapsed or refractory (R/R) acute myeloid leukemia (AML; acute promyelocytic leukemia excluded). After leukapheresis for CAR-T cell manufacture, participants receive lymphodepleting conditioning (fludarabine 30 mg/m\^2/day plus cyclophosphamide 300 mg/m\^2/day on Days -5 to -3), followed by a single intravenous infusion of CLL-1-CD70 CAR-T cells. Dose escalation follows a traditional 3+3 design with planned dose levels of 0.5 x 10\^6, 1 x 10\^6, and 2 x 10\^6 CAR-T cells/kg, guided by dose-limiting toxicities (DLTs) assessed during Days 1-28 after infusion. The primary endpoint is safety and tolerability, as assessed by treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs), including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), hematologic toxicity, organ toxicity, infections, hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS), and tumor lysis syndrome (TLS). Efficacy will be evaluated by the composite complete remission rate (CRc, defined as the proportion of patients achieving CR, CRh, or CRi) at prespecified time points according to the European LeukemiaNet (ELN) 2022 criteria, overall survival (OS), event-free survival (EFS), duration of response (DOR), and cumulative incidence of relapse (CIR) over a 1-year follow-up period. Immune reconstitution following CAR-T cell infusion will also be assessed at prespecified time points. CAR-T cellular kinetics in peripheral blood (CAR transgene copies, Cmax, Tmax, and AUC0-28d) will also be evaluated.