Effect of allogeneic hematopoietic cell transplantation in first complete remission on post-relapse complete remission rate and survival in acute myeloid leukemia.

Several studies have shown that allogeneic hematopoietic cell transplantation (HCT) in first complete remission (CR1) of AML reduces the risk of relapse and improves relapse-free survival in intermediateand poor-risk AML. Benefits in (overall) survival are less obvious. One possible explanation is that following the occurrence of relapse, previous receipt of allogeneic HCT in CR1 is associated with shorter survival, with a lower CR rate following therapy for relapse (salvage therapy) being a possible contributing factor. Breems et al. reported that in 667 adults age < 60, HCT in CR1 was independently associated with shorter survival after subsequent relapse, with 58 patients receiving allogeneic and 102 autologous HCT. Second CR rate was 33% when HCT had been done in CR1, and 49% if it had not. Burnett et al. noted that survival after relapse was shorter in their 1,064 patients receiving HCT in CR1 than in patients not transplanted in CR1; 23% of the 1,064 patients received autologous HCT and CR rates in these 1,064 were not reported. The aims of our study were to analyze the effect of, specifically, allogeneic HCT in CR1 on the probabilities of (a) achieving second CR (CR2) with first salvage therapy, and (b) survival from first salvage. We identified 173 consecutive patients with AML (APL excepted) or MDS with 10-19% blasts who, after achieving CR1 (< 5% morphologic blasts in marrow, ANC > 1,000 and platelets > 100,000 micro/L) with initial treatment, relapsed (> 5% blasts in marrow and/or blood unrelated to recovery of blood counts) between 2008 and 2013 at our center. 161 of the 173 received first salvage therapy. From these 161, we collected data on: (1) age, (2) secondary vs. de novo AML, (3) CR1 duration, (4) number of initial induction courses, (5) number of post-remission courses, (6) ECOG performance status at relapse, (7) cytogenetic category (ELN criteria for adverse, intermedi-