Impact of conditioning with TBI in adult patients with T-cell ALL who receive a myeloablative allogeneic stem cell transplantation: a report from the acute leukemia working party of EBMT

Abstract

on behalf of the Acute Leukemia Working Party of EBMT Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a therapeutic option for adult patients with T-cell ALL (T-ALL). Meanwhile, few allo-SCT data specific to adult T-ALL have been described thus far. Specifically, the optimal myeloablative conditioning regimen is unknown. In this retrospective study, 601 patients were included. Patients received allo-SCT in CR1, CR2, CR 42 or in advanced disease in 69%, 15%, 2% and 14% of cases, respectively. With an overall follow-up of 58 months, 523 patients received a TBI-based regimen, whereas 78 patients received a chemotherapy-based regimen including IV busulfan-cyclophosphamide (IV Bu-Cy) (n = 46). Unlike patients aged ⩾ 35 years, patients aged o 35 years who received a TBI-based regimen displayed an improved outcome compared with patients who received a chemotherapy-based regimen (5-year leukemia-free survival (LFS) of 50% for TBI versus 18% for chemo-only regimen or IV Bu-Cy regimens, P = 10 − 5 and 10 − 4 , respectively). In multivariate analysis, use of TBI was associated with an improved LFS (hazard ratio (HR) = 0.55 (0.34-0.86), P = 0.01) and overall survival (HR = 0.54 (0.34-0.87), P = 0.01) in patients aged o 35 years. In conclusion, younger adult patients with T-ALL entitled to receive a myeloablative allo-SCT may benefit from TBI-based regimens.

Allogeneic hematopoietic cell transplantation for primary refractory acute lymphoblastic leukemia: A report from the Acute Leukemia Working Party of the EBMT

“…There still is uncertainty regarding the optimal conditioning regimen in patients with ALL. Our observations are in keeping with the results of several published trials suggesting the superiority of TBI‐containing regimens . Although in the most recent of these studies intravenous busulfan was the most common chemotherapy‐only regimen, some doubts remain regarding whether the intravenous administration could eliminate the survival advantages of TBI in patients with ALL as appears to be the case in patients with PREF AML …”

Allogeneic Hematopoietic Cell Transplantation for Adult T Cell Acute Lymphoblastic Leukemia

“…Survival also was better in patients undergoing HCT in CR1 compared to ≥CR2, with better survival in patients age <35 years receiving a TBI-based MAC regimen compared with those receiving a busulfan- or cyclophosphamide-based MAC regimen [5]. Although we observed no impact of specific conditioning regimen on survival, we also verified that the use of TBI in this disease was associated with better survival.…”

Thiotepa‐based conditioning versus total body irradiation as myeloablative conditioning prior to allogeneic stem cell transplantation for acute lymphoblastic leukemia: A matched‐pair analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

“…As shown in Bu/Cy radiation-free conditioning in terms of LFS and OS. 17 In the same vein, a recent analysis undertaken by the EBMT in more than 4000 ALL patients also indicated that the use of TBI-based conditioning led to a reduced risk of relapse as well as treatment failure. 18 In our current analysis, we aimed to determine whether thiotepa- 19 While admittedly this was a small cohort of patients, it is however important to note that these were patients with relapsed disease who were able to achieve an impressive 3-year OS rate of 49% following thiotepa-based conditioning further underscoring the potent anti-leukemia activity attainable with this preparative radiation-free regimen.…”