Open Access

Allogeneic hematopoietic cell transplantation is a potentially curative treatment in high-risk acute lymphoblastic leukemia (ALL). Conditioning regimens based on ≥12 Gray total body irradiation (TBI) represent the current standard in patients ≤45 years, whereas elderly patients frequently receive intermediate intensity conditioning (IIC) to reduce toxicity. To evaluate the role of TBI as a backbone of IIC in ALL, a retrospective, registry-based study included patients >45 years transplanted from matched donors in first complete remission, who had received either fludarabine/TBI 8 Gy (FluTBI8, n = 262), or the most popular, irradiation-free alternative fludarabine/busulfan, comprising busulfan 6.4 mg/kg (FluBu6.4, n = 188) or 9.6 mg/kg (FluBu9.6, n = 51). At two years, overall survival (OS) was 68.5%, 57%, and 62.2%, leukemia-free survival (LFS) was 58%, 42.7%, and 45%, relapse incidence (RI) was 27.2%, 40%, and 30.9%, and non-relapse-mortality (NRM) was 23.1%, 20.7%, and 26.8% for patients receiving FluTBI8Gy, FluBu6.4, and FluBu9.6, respectively. In multivariate analysis, the risk of NRM, acute and chronic graft-versus-host disease was not influenced by conditioning. However, RI was higher after FluBu6.4 (hazard ratio [HR] [95% CI]: 1.85 [1.16–2.95]), and LFS was lower after both FluBu6.4 (HR: 1.56 [1.09–2.23]) and FluBu9.6 (HR: 1.63 [1.02–2.58]) as compared to FluTBI8. Although only resulting in a non-significant advantage in OS, this observation indicates a stronger anti-leukemic efficacy of TBI-based intermediate intensity conditioning.

Abstract Acute myeloid leukemia (AML) with translocation t(8;16)(p11;p13) represents a rare entity that has been categorized as a disease‐defining recurring cytogenetic abnormality with adverse risk in the 2022 European LeukemiaNet classification. This rating was mainly based on a retrospective analysis comprising patients from several large clinical trials, which, however, included only 21 patients treated with allogeneic stem cell transplantation (alloSCT). Therefore, the European Society for Blood and Marrow Transplantation performed a registry study on a larger cohort to evaluate the role of alloSCT in t(8;16) AML. Sixty transplant recipients with t(8;16) AML were identified. Two‐year overall and leukemia‐free survival (OS/LFS) was 43/39%. Patients transplanted in first complete remission (CR1, n  = 44) achieved a 2‐year OS/LFS of 48%/48%. Following alloSCT in CR1, the multivariable analysis identified a complex karyotype (CK) as a major risk factor for relapse (HR 4.17, p  = .016), lower LFS (HR 3.38, p  = .01), and lower OS (HR 3.08, p  = .017). Two‐year OS/LFS of patients with CK was 19%/19%, in contrast to 67%/67% in patients with t(8;16) outside a CK. Other factors for inferior outcomes were older age and secondary AML. In summary, alloSCT could mitigate the adverse risk of patients with t(8;16) AML not harboring a CK, particularly when performed in CR1.