Best Abstract award in EBMT 2020, Madrid
O066 - FLAMSA-BASED REDUCED INTENSITY CONDITIONING VERSUS MYELOABLATIVE CONDITIONING IN PATIENTS WITH RELAPSED/REFRACTORY ACUTE MYELOID LEUKEMIA WITH ACTIVE DISEASE AT THE TIME OF TRANSPLANTATION: AN ALWP/EBMT ANALYSIS
Methods: This was a retrospective registry-based analysis performed by the ALWP of the EBMT. Eligibility criteria included age 18-50 years, primary refractory, first or second relapsed active AML, first alloSCT from a matched sibling donor (MSD) or an unrelated donor (UD) performed between 2005 and 2018, MAC with cyclophosphamide and total body irradiation (Cy/TBI) or busulfan/cyclophosphamide (Bu/Cy), or FLAMSA-RIC. The study endpoints were overall survival (OS), relapse incidence (RI), leukemia-free survival (LFS), non-relapse mortality (NRM), acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD) and refined graft-versus-host disease, relapse-free survival (GRFS). Cox proportional hazards regression models (cause-specific for competing risk data) were constructed for all outcome measures.
Results: A total of 1018 patients were included. Median age was 39 (range 18-50) years. Two hundred fifty-eight patients received Bu/Cy, 314 Cy/TBI, 318 FLAMSA-TBI and 128 FLAMSA-chemotherapy without TBI (CT). Bu/Cy (53%) was the most common regimen among patients receiving FLAMSA-CT, followed by melphalan (17%) and Bu (14%). Patients in the MAC group were more likely to have received an alloSCT from a MSD (39% vs. 30% and 24% in the FLAMSA-TBI and FLAMSA-CT groups, p< 0.01), and less likely to have received ATG (32% vs. 87% and 84%, p< 0.01). There were no significant differences in the distributions of Karnofsky performance status, cytogenetic risk, secondary AML or disease status at transplantation. Median follow-up was 50.2 months.
In univariate analysis, 2-year RI (54% [95% CI: 50-57]), LFS (30% [95% CI: 27-33]) and GRFS (21% [95% CI: 18-24]) were not significantly different between cohorts. Lower 2-year NRM was observed in the FLAMSA-CT group (7% vs. 16% in Bu/Cy, 19% in Cy/TBI and 18% in FLAMSA-TBI; p=0.04), as well as increased 2-year OS (50% vs. 33% in Bu/Cy, 34% in Cy/TBI and 36% in FLAMSA-TBI; p=0.03). These results were maintained in the multivariate analysis (HR for NRM: 0.41, p=0.01; HR for OS: 0.67, p=0.01; Bu/Cy as reference). Conditioning regimen had no impact on grade II-IV aGVHD (35% [95% CI: 32-38]) or 2-year extensive cGVHD (12% [95% CI: 10-15]). Additionally, adverse cytogenetics and second relapse status were associated with an increase in RI and lower OS in the multivariate model.
Conclusions: MAC or FLAMSA-TBI resulted in similar outcomes among patients with R/R AML with active disease at the time time of alloSCT. FLAMSA-CT was associated with reduced NRM, leading to an OS benefit as compared with MAC and FLAMSA-TBI.
Disclosure: Nothing to declare.
Participants: Dr Liga, Dr Spyridis, Dr Fragopanagou, Dr Lekka, Dr Kostopoulou