CD7 chimeric antigen receptor T cells in patients with relapsed or refractory CD7-positive acute myeloid leukemia

Although CAR-T cell therapy has revolutionized treatment for hematologic malignancies, its application in acute myeloid leukemia remains challenging. CD7 is expressed in approximately 30% of AML cases and represents a promising target. This phase I clinical trial (NCT04599556) evaluated CD7-targeted CAR-T cell therapy in patients with relapsed/refractory CD7-positive AML. Patients received a single infusion of autologous or donor-derived CD7 CAR-T cells using a standard 3 + 3 dose escalation design across two dose levels. The primary endpoint was the incidence of dose-limiting toxicities. Fourteen patients were enrolled. Treatment-related adverse events included cytokine release syndrome (92.9%), grade 3-4 cytopenia (100%), grade 1 neurotoxicity (7.1%), and viral reactivation (78.6%). The objective response rate was 92.3%, with an MRD-negative rate of 84.6%. Despite initial responses, seven patients relapsed with CD7-negative disease. At a median follow-up of 172.5 days, five patients remained in remission. The 3-year overall survival and leukemia-free survival rates were 34.3% and 34.1%, respectively. These initial results indicate that CD7 CAR-T cell therapy exhibits a manageable safety profile and preliminary efficacy in R/R AML patients, supporting further investigation in larger trials.