[A clinical study of allogeneic hematopoietic stem cell transplantation in 23 patients with early T-cell precursor acute lymphoblastic leukemia]

Objective: Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a recently recognized high-risk T lymphoblastic leukemia subgroup. The optimal therapeutic approaches to adult patients with ETP-ALL are poorly characterized. In this study, we explore the efficacy and outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for ETP-ALL. Methods: The clinical data of 23 patients with ETP-ALL receiving allo-HSCT from 2010 to 2018 were retrospectively analyzed. Patients with ETP-ALL were diagnosed based on the characteristic immunophenotypes. Second-generation sequencing was done in all patients. As to the donors, 12 patients had haploidentical donors (Haplo-HSCT) , 7 HLA-matched sibling donors (Sib-HSCT) and 4 HLA-matched unrelated donors (URD-HSCT) . Before transplantation, 19 patients achieved complete remission (CR) and 4 patients without. Results: The main clinical features of ETP-ALL included high white blood cell counts in 5 patients, splenomegaly in 14, lymphadenopathy in 19, and thymus masses in 5. According to cytogenetic and molecular characteristics, 11 patients had gene mutations related to myeloid tumors, and 7 with high risk Karyotype. After first induction regimen, 14/23 patients achieved CR. 5 patients reached CR after more than 2 cycles of chemotherapy, while another 4 patients did not reach CR. After allo-HSCT, 22 patients were successfully implanted. The median time of granulocyte and platelet reconstitution was +12 and +19 days. One patient died of transplant-related infection at +14 days. The estimated 18-month overall survival (OS) and relapse-free survival (RFS) rates were (55.0±14.4) % and (48.1±14.7) % respectively. Transplant-related mortality was 4.3%. The median OS in patients achieving CR before transplantation was 20 months, however, that in patients without CR was only 13 months. OS and RFS between haplo-HSCT and sib-HSCT were comparable (P=0.460 and 0.420 respectively) . Conclusions: Allo-HSCT is an effective therapy in some patients with ETP-ALL. Salvage HSCT cannot overcome the poor outcome. Haplo-HSCT and sib-HSCT in ETP-ALL patients have the similar clinical outcome.