Efficacy and safety of CD19 CAR-T cell therapy for patients with B cell acute lymphoblastic leukemia involving extramedullary relapse.

Abstract

To evaluate the efficacy and safety of CD19 chimeric antigen receptor (CAR) T cell therapy for patients with B cell acute lymphoblastic leukemia (B-ALL) involving extramedullary relapse. Fifteen patients with B-ALL involving extramedullary relapse who received CD19 CAR-T cell therapy in the First Affiliated Hospital, Zhejiang University School of Medicine from January 2016 to October 2021 were enrolled in this study. The overall survival and leukemia-free survival of patients were analyzed using Kaplan-Meier curves, and the response of extramedullary lesions in different locations following the CD19 CAR-T cell therapy was observed. Cytokine release syndrome (CRS), hematological toxicity, and immune effector cell-associated neurotoxicity syndrome (ICANS) during CD19 CAR-T cell therapy were analyzed. The median follow-up time was 7 (3-71) months, and 11 cases (73.3%) achieved complete response, median duration of complete response was 6 (2-27) months; 3 cases (20.0%) achieved partial response; 1 case (6.7%) got progressive disease. The overall response rate was 93.3% (14/15), and the overall survival rate was 80.0% (12/15) at the end of follow-up. The cumulative incidence of relapse was 40.0% (6/15) and relapse mortality rate was 20.0% (3/15). Until last follow-up date, 9 cases (60.0%) were still in disease-free survival. Among the 15 patients, 13 cases (86.7%) developed cytokine release syndrome (CRS) after cell infusion, including 7 cases with grade 1-2 CRS, 6 cases with grade 3 CRS; 1 case suffered from reversible ICANS; 15 cases (100.0%) developed B cell dysplasia; 12 cases (80.0%) developed severe hematologic adverse reactions; 2 cases (13.3%) had abnormal liver function; 1 case (6.7%) had abnormal renal function; 4 cases (26.7%) developed infection. The adverse reactions mentioned above were well controlled. CD19 CAR-T cell therapy shows explicit efficacy and controllable adverse reactions for B-ALL patients with extramedullary relapse.