Favourable outcome of allogeneic stem cell transplantation for patients with intermediate-risk AML in 1.CR--A single-centre experience from 2003-2008

Objectives: allogeneic stem cell transplantation (alloSCT) using myeloablative conditioning (MAC) and related donors for patients (pts) with intermediate-risk AML in 1.CR improves disease-free survival (DFS) and relapse incidence (RI) in comparison with pts treated by chemotherapy (CHT). The impact on overall survival (OS) was not so clearly demonstrated due to higher treatment-related mortality (TRM). Reduced-intensity conditioning (RIC), the use of unrelated donor, new supportive therapy and diagnostic procedures introduced in recent years can affect results of alloSCT. To evaluate the role of these factors we retrospectively analysed outcome of pts with intermediaterisk AML in 1.CR transplanted in last 5 years at our transplant centre and we also compare their outcome with pts indicated for allo-SCT but treated by chemotherapy (CHT) due to lacking of donor or refusal of alloSCT. Methods: since 2003 30 consecutive pts with median of age 52 years (range 28-59) with intermediate-risk AML in 1.CR underwent alloSCT from related (43%) or unrelated (57%) donor after MAC (40%,BU/CY) or RIC (60%,FLU/MEL). The source of stem cell was peripheral blood in 93%. GVHD prophylaxis were CSA/MTX. The control group consisted of 19 pts with intermediate-risk AML in 1.CR indicated for alloSCT but treated by CHT due to lacking of donor or refusal of allo-SCT. The control group except for the younger age did not differ in any prognostic parameters. Results: all transplanted pts engrafted. 9 pts (30%) developed acute GvHD and among 25 evaluable pts 9 pts (36%) developed chronic GvHD. 3 pts (10%) relapsed and 5 pts (16%) died due to TRM. The estimated probabilities of 3-years DFS and OS were 84% and 60%. Type of donor or conditioning regimen did not have any statistical influence on transplant results. Among CHT treated pts 2 (11%) of them died due to TRM and 10 pts (53%) relapsed. The estimated probabilities of 3-years DFS and OS were 31% and 40%. AlloSCT with comparable TRM (p=0,69) significantly improved DFS (p=0.001), cumulative RI (p=0,002) and there was a trend for better OS (p=0,10) in comparison with CHT. Conclusions:1. in comparison with CHT alloSCT with low TRM in recent years and low RI improved DFS of pts with intermediaterisk AML in 1.CR. The smaller difference in OS can be explained by the effect of salvage treatment of relapsed pts in CHT group (80% salvage treatment, 50% alloSCT). 2. OS after alloSCT was not influenced by type of donor or conditioning regimen.