Lymphodepletion chemotherapy revitalizes chimeric antigen receptor T cells contributing to regression of relapsed B-cell lymphoma: A case report

INTRODUCTION: Chimeric antigen receptor T cells (CAR-T) targeting CD19 have shown great potential for treatment of B-cell malignancies. For those patients who can not achieve complete remission (CR) or suffer from relapse after CAR-T therapy, further therapeutic strategies still remain elusive. Whether existing CAR-T cells can revitalize in vivo and eradicate tumor cells is still unknown. PATIENT CONCERNS: We report a case of diffused large B-cell lymphoma patient who had achieved CR after CD19 targeted CAR-T therapy but relapsed after 5 months. DIAGNOSIS: Five months after CAR-T cell infusion, the patient was confirmed a relapse by follow-up PET/CT scan and a mass biopsy. Flow cytometry showed a dramatically decreased percentage of CAR-T cells in peripheral blood (PB). INTERVENTIONS: A second anti-CD19 CAR-T therapy was planned with deliberation. Firstly, the patient received lymphodepletion chemotherapy with fludarabine (25 mg/m(2), d1–d3) and cyclophosphamide (500 mg/m(2) d2–d3). OUTCOMES: After fludarabine and cyclophosphamide (FC) lymphodepletion chemotherapy, pre-existing CAR-T cells were revitalized and the patient developed grade 2 cytokine release syndrome (CRS) contributing to the regression of relapsed B-cell lymphoma. CONCLUSIONS: This case suggested that FC chemotherapy could revitalize CAR-T cells contributing to the regression of relapsed B-cell lymphoma. Nevertheless, further researches are required in the future as this report described only a single case.