The AntiCD19 Antibody Drug Immunoconjugate Loncastuximab Achieves Responses in DLBCL Relapsing After AntiCD19 CAR-T Cell Therapy

Abstract Chimeric antigen receptor T (CAR-T) cells targeting CD19 result in durable responses in approximately 40% of DLBCL patients. Loncastuximab tesirine, an antibody drug conjugate targeting CD19 with a pyrrolobenzodiazepine payload, has activity against DLBCL. We evaluated the outcomes of 13 DLBCL patients relapsed after CAR-T cells treated with loncastuximab in the LOTIS-2 trial. Six patients (46%) had responses to loncastuximab (CR, n = 2). Median OS, PFS and duration of response after loncastuximab was 8.2, 1.4 and 8 months, respectively. Loncastuximab can achieve responses in patients progressing after CAR-T cells. Sequencing CD19-targeting therapies is possible in cases without CD19 loss.