EBMT 2018 | Allo-HSCT for CBF-AML patients in CR2

At the 44^th Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT), Lisbon, Portugal, the AML Global Portal (AGP) attended an oral session on acute leukemias. At this session, Kazimierz Halaburda from the Institute of Haematology and Transfusion Medicine, Stem Cell Transplantation, Warsaw, PL, presented results from a retrospective study, which is evaluating the clinical factors influencing outcomes of core binding factor (CBF) acute myeloid leukemia (AML) patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in second complete remission (CR2). The primary endpoint of the study was 2-year leukemia-free survival (LFS).

In total, 631 CBF-AML patients (median age = 42 years, range: 18–74) in CR2 who were transplanted either from a related (n = 264, 42%) or an unrelated donor (n = 367, 58%) between 2000–2014 and reported to the EBMT registry were analyzed in this study. Patients were diagnosed with abnormalities in inv(16)/t(16;16) (n = 366 [58%]), t(8;21) (n = 265 [42%]) and in other chromosome abnormalities (n = 32, 5%) with  ≥ 3 abnormalities (≥3 abn) being the most frequent.  At the time of transplantation, molecular remission (MR) was achieved in 73% (n = 343) of patients, the remaining 27% (n = 125) of patients were transplanted with no MR. Median follow-up time for surviving patients was 60 months (0.9–201).

Key findings:

• Outcomes in all patients

  • 2-year LFS: 59.1%
  • 2-year overall survival (OS): 65%
  • 2-year relapse incidence (RI): 19.8%
  • 2-year non-relapse mortality rate: 20.9%
  • 2-year gvhd relapse/leukemia free survival: 40.2%
• Compared to patients with t(8;21) abnormality, patients with inv(16)/t(16;16)) had a better LFS (P = 0.003), OS (P = 0.0003) and a reduced RI (P = 0.009)
• Type of AML (t(8;21) vs inv(16)/t(16;16)) and presence or absence of ≥ 3 abnormalities were independent factors influencing LFS: HR = 1.398, P = 0.002 and HR = 2.089, P = 0.004 respectively
• Compared to patients with no MR, patients with MR had an improved LFS (P = 0.15), a lower RI (P = 0.06) and no change in OS (P = 0.95)

The speaker, Kazimierz Halaburda, concluded by stating that allo-HSCT in CR2 significantly contributed to favorable outcomes in patients with CBF-AML. Moreover, superior outcomes were observed in patients with inv(16)/t(16;16) compared to t(8;21).                                     

Additionally, “MR decreased the risk of relapse with a trend for improved LFS without affecting OS, indicating the effectiveness of allo-HSCT even in patients not achieving MR before transplantation”.