# Case Report: CD19 CAR-T cells derived from recipient of umbilical cord blood transplantation effectively treated relapsed acute lymphoblastic leukemia after UCBT

## TL;DR

A patient with relapsed leukemia was successfully treated with CAR-T cells made from their own cells after umbilical cord blood transplantation.

## Contribution

This is the first case showing CAR-T cells from UCBT recipients can effectively and safely treat relapsed ALL.

## Key findings

- The patient achieved complete remission after CD19 CAR-T treatment.
- No severe side effects like GVHD or neurotoxicity were observed.
- The patient remained in remission for over six years with no detectable minimal residual disease.

## Abstract

Recent advances in chimeric antigen receptors have provided an alternative approach for treating relapsed acute lymphocyte leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, relapsed patients who had undergone allogeneic umbilical cord blood transplantation (UCBT) have no chance of having CAR-T cells derived from donors due to lacking UCB. We present a case of a patient with Ph+ ALL who relapsed after UCBT and achieved complete morphological and molecular remission following treatment with CD19 CAR-T cells derived from the recipient post-UCBT. The patient had only grade I CRS. GVHD or neurotoxicity was not observed. More than 6 years after CAR-T cell infusion, the patient was still in hematologic and molecular complete remission with negative minimal residual disease (MRD). This case is the first to show a new strategy of practicality, efficacy, and safety of CD19 CAR-T cells derived from UCBT recipients for treating relapsed ALL after UCBT.