Abstract
Adult T-cell Leukemia/Lymphoma (ATLL) is a rare and aggressive malignancy caused by the human T-cell leukemia virus type 1 (HTLV-1) that carries a dismal prognosis. Hematopoietic stem cell transplantation (HCT) provides the potential for long-term survival. ATLL is often diagnosed in Afro-Caribbean and Latin American (LATAM) patients in the USA and Europe. However, there is a substantial lack of HCT outcome data in these populations. This study aims to compare outcomes among patients with ATLL who received HCT grafts from matched or alternative donors at our institutions.
Patients with ATLL who underwent HCT between 2012 - 2024 were included. Descriptive statistics was used to describe baseline characteristics. Progression-free and overall survival were calculated using Kaplan-Meier estimates. Log rank test was used to explore the association between clinical characteristics and PFS/OS.
Baseline demographics are presented in table 1. Forty-six (46) patients were included with median age 53.5 years. The majority of patients were of Afro-Caribbean ethnicity. Fifty-three (53) percent of patients had acute subtype ATLL and 21 had lymphomatous subtype. Median # of prior lines of treatment was 2, with 71.7% in CR at HCT. Most patients received CHOP pre-HCT. Myeloablative conditioning (MAC) was used in 21.7% of patients, with 54.3% underwent alternative donor HCT. Median PFS and OS (post HCT) for all patients was 9.1 and 16.8 months, respectively. Acute subtype ATLL patients had significantly worse OS (HR 0.44, p=0.048) compared to lymphomatous subtype (Figure 1). There was no difference in OS between matched versus alternative donor HCT (HR 0.81, p=0.6).
On univariable analysis, significant predictors for adverse survival included chemotherapy use of platinum-based (HR 2.27, p=0.035), response of non-CR versus CR at HCT (HR 2.55, p = 0.019). KPS of ≥ 80 at HCT (HR 0.32, p=0.001) showed a favorable HR. Lymphomatous subtype also trended towards favorably (HR 0.44, p = 0.055). A multivariable model for OS found subtype of lymphomatous disease was significantly associated with reduced risk of death by 68% (HR=0.32, p=0.029), and KPS at HCT ≥80 was also a significant predictor of longer OS (HR=0.23, p=0.007).
As the largest series of transplant outcomes for Afro-Caribbean and LATAM patients with ATLL, we found no difference in outcomes between matched or alternative donor HCT. Acute disease subtype fared substantially worse than lymphomatous subtype after HCT. Novel transplant methods or maintenance strategies are needed to improve survival after HCT for patients with ATLL.