Updated data of CLL1 CAR-T cell therapy in adult patients with relapsed/refractory acute myeloid leukemia

CLL1-targeted chimeric antigen receptor T (CAR-T) cell therapy has shown clinically meaningful activity in relapsed/refractory acute myeloid leukemia (R/R AML). This updated phase I study enrolled 38 adults with R/R AML to evaluate the safety and efficacy of this treatment according to the prespecified protocol. Treatment-related adverse events included grade 3/4 cytokine release syndrome (CRS) in 17 patients (44.74%) and grade 4 immune effector cell-associated neurotoxicity syndrome (ICANS) in 1 patient (2.63%). Persistent cytopenia (all grades) was observed in all patients, with a median time to neutrophil recovery of 45 days. At a median follow-up of 24.87 months, the objective response rate (ORR) was 73.68% (28/38), and the minimal residual disease-negative complete response rate (MRD^-CR) was 42.11%. Median progression-free survival (PFS) and overall survival (OS) were 9 months (95%CI 3.03-14.47) and 12.17 months (95%CI 3.03-24.87), respectively. The two-year PFS and OS rates were 47.94% (95%CI: 32.00%-63.83%) and 51.43% (95%CI 35.51%-67.32%), respectively. These results indicate a clinically relevant antitumor efficacy and a manageable safety profile of CLL1-targeted CAR-T cell therapy in adults with R/R AML.Registry: www.chictr.org.cn , TRN: ChiCTR2000041054, Registration date: 17 December 2020.