Allogeneic Stem Cell Transplantation in 59 Patients with Adlut T-Cell Leukemia/Lymphoma-A Single center’s 13 Years Experience-
Authors: Nakano Nobuaki , Takatsuka Yoshifusa , Takeuchi Shogo , Tokunaga Masahito , Kubota Ayumu , Tokunaga Mayumi , Itoyama Takahiro , Makino Torahiko , Utsunomiya Atae 
Published: October 2019

Abstract
Abstract 4483
Adult T-cell leukemia/lymphoma (ATLL) is one of human T-cell leukemia virus type 1 (HTLV-1) related diseases and is usually characterized as CD4+CD8-CD25+ peripheral T-cell lymphoma with very poor prognosis. Although many chemotherapeutic regimens had been created, median duration of survival was up to about 13 months in the patients of acute type, lymphoma type and chronic type with poor prognostic factors so far. Several reports suggested allogeneic stem cell transplantation (allo-SCT) improved survival outcomes. This study in a single institute, located in endemic area of ATLL, reports the clinical outcomes about our 13 years experiences of allo-SCT for ATLL. There were 59 (33 male, 26 female) ATLL patients who have consecutively undergone allo-SCT between June 1998 and March 2011 at Imamura Bun-in Hospital. Median age was 50 (range: 32–65) years. Fifty patients were considered 0–1 of ECOG performance status (PS) and rest of 9 were ≥2 at the time of SCT. Fifty-three patients out of 59 were diagnosed as acute type ATLL, 5 lymphoma type, and one chronic type with poor prognostic factors at the time of transplantation, respectively. Stem cell sources were 36 BM (9 related donors, 27 unrelated donors), 19 PB and 4 CB, respectively. Thirty-five patients received myeloablative conditioning (MAC) regimens and 24 reduced intensity conditioning (RIC) regimens. Forty-seven patients out of 59 were used busulfan based non-TBI regimens. Sixteen patients were in CR at SCT, and 43 non-CR (9 PR, 16 SD, and 18 PD), respectively. Cumulative incidence of ANC recovery (≥500/μ l) was 98.2% after SCT. Probabilities of grade I to IV, II to IV acute GVHD and chronic GVHD were 71%, 44%, and 31%, respectively. Interestingly, the incidence of CMV viremia, defined CMV-related external matrix protein pp65-antigenemia positive in blood, after SCT was extremely high (94.4%) in ATLL patient status post SCT compared with reported other diseases. Overall survival (OS) and disease free survival (DFS) at 2 years after SCT were 44.5% and 32.5%, respectively. Five-yrs OS and DFS were 26.4% and 22.6% respectively. Notably, 2-yrs and 5-yrs OS in CR patients were 72.7% and 48.5%, respectively. Cumulative incidence of relapse at day100 and 1 year after SCT were 33.2% and 49.2% respectively. Also cumulative incidence of non-relapse mortality (NRM) at day100 after SCT was 20.4%. In univariate analysis, significant factors contributed to OS were CR status and 0–1 of PS at SCT, incidence of acute and chronic GVHD, and non-TBI regimen. CR status, 0–1 of PS at SCT, and incidence of chronic GVHD were significant factors contributed to favorable outcome about DFS. MAC regimens didn’t show favorable significance contributed to OS and DFS, but reduced the incidence of early relapse compared with RIC regimens. In multivariate analysis, CR status at SCT, incidence of acute and chronic GVHD, and non-TBI regimen significantly contributed to favorable outcome about OS and CR status, 0–1 of PS at SCT, and incidence of chronic GVHD contributed to favorable outcome about DFS. In conclusion, considering large number of non-CR patients included in this study, 44.5% of 2-yrs OS and 20.4% of NRM at day 100 after SCT suggested allo-SCT can be promising treatment for ATLL and graft-versus-ATLL effect possibly exist given that chronic GVHD was shown as one of favorable factors about OS and DFS.

Disclosures:
No relevant conflicts of interest to declare.