Allogeneic Hematopoietic Cell Transplantation for Adult T Cell Acute Lymphoblastic Leukemia

Allogeneic hematopoietic cell transplantation (HCT) is recommended for patients with T cell acute lymphoblastic leukemia (T-ALL) in second or later complete remission (CR) and high-risk patients in first CR. Given its relative rarity, data on outcomes of HO' for T-ALL are limited. We conducted a multicenter retrospective cohort study using data from 208 adult patients who underwent HO' between 2000 and 2014, to describe outcomes of allogeneic HO' for T-ALL in the contemporary era. The median age at HO' was 37 years, and the majority of patients underwent HO' in CR, using total body irradiation (TBI)-based myeloablative conditioning regimens. One-quarter of the patients underwent alternative donor HO' using a mismatched, umbilical cord blood, or haploidentical donor. With a median follow up of 38 months, overall survival at 5 years was 34%. The corresponding cumulative incidence of non-relapse mortality and relapse was 26% and 41%, respectively. In multivariable analysis, factors significantly associated with overall survival were the use of TBI (HR, 0.57; P=.021), age >35 years (HR, 1.55; P=.025), and disease status at HCT (HR, 1.98; P=.005 for relapsed/ refractory disease compared with CR). Relapse was the most common cause of death (58% of patients). Allogeneic HO' remains a potentially curative option in selected patients with adult T-ALL, although relapse is a major cause of treatment failure. (C) 2017 American Society for Blood and Marrow Transplantation.