[Safety and efficacy of patients with refractory B-lymphoblastic leukemia treated with anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation].

Objective: To investigate the efficacy and side effects of anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation (allo-HSCT) regimen for refractory B-lymphoblastic leukemia. Methods: 10 patients with refractory B-lymphoblastic leukemia with minimal residual disease (MRD) negative after anti-CD19 CAR-T cell treatment, then bridging to allo-HSCT from November 2017 to March 2019 in the Affiliated Cancer Hospital of Zhengzhou University were retrospectively analyzed. Results: ①Among 10 patients, 5 were males and 5 females, with a median age of 23.6 (10-31) years. 9 patients were diagnosed refractory acute lymphoblastic leukemia and the other one was chronic lymphoblastic leukemia. 10 patients reached MRD negative 30 days after anti-CD19 CAR-T cell. ②The donors were identical sibling (2 cases) and haploidentical family member (8 cases) . The median time from MRD negative after CAR-T treatment to transplantation were 32.5 (20-60) days. ③10 patients obtained complete haploidentical engraftment. The median time of neutrophil implantation was 15 (15-21) days, and 19 (17-30) days of platelet implantation. ④ After conditioning, no hepatic venoocclusive disease and hemorrhagic cystitis occurred. One patient had leakage syndrome and got improved after intervention such as limited water entry, albumin supplementation and diuresis. 8 (80%) patients had fever, 2 cases experienced acute graft-versus-host disease (GVHD) grade Ⅱ, 1 case with aGVHD grade Ⅲ. Among 9 survivals, localized chronic GVHD occurred in 8 patients. ⑤The median follow-up was 262 (150-540) days and the estimated 1-years overall survivaln (OS) and disease free survival (DFS) were (90.0±1.0) % and (85.7±1.3) %, respectively. Conclusion: Anti-CD19 CAR-T cell bridging to allo-HSCT regimen is a feasible choice with favorable outcome for refractory B-lymphoblastic leukemia.