Successful treatment of second-time CAR-T 19 therapy after failure of first-time CAR-T 19 and ibrutinib therapy in relapsed mantle cell lymphoma

Background: A patient with relapsed mantle cell lymphoma (MCL) showed stable disease after receiving ibrutinib therapy as a salvage therapy, after the failure of his first chimeric antigen receptor (CAR)-T 19 cell therapy.

Objectives: The combined effects of CAR-T 19 cells from the patient and ibrutinib on JeKo-1 cell were explored in vitro and in vivo.

Material and methods: The expression of programmed death-1 (PD-1) receptor on CD3+ T cells in the peripheral blood decreased from 82.95% in the first CAR-T 19 cell therapy to approx. 40% after 14 months of ibrutinib therapy. When the disease progressed again during the ibrutinib therapy, the patient was enrolled into the same clinical trial of CAR-T 19 cell therapy.

Results: The efficacy of CAR-T 19 cells increased after the ibrutinib therapy. The mRNA expression level of PD-1 in CAR-T 19 cells after ibrutinib therapy was lower than in CAR-T 19 cells before the ibrutinib therapy. Nevertheless, CAR-T 19 cell therapy combined with ibrutinib had no synergistic effect in a short term in vitro and in the JeKo-1 cell mouse model.

Conclusion: We expect our results to provide evidence for the combination treatment of ibrutinib for MCL or even other types of B-cell lymphomas. Moreover, the improvement in CAR-T 19 cell function was based on long-term ibrutinib therapy.