Allogeneic hematopoietic stem cell transplant (HSCT) in adults with acute myeloid leukemia (AML) – a single program experience

From 1/00 to 4/05, 93 patients (pts) with AML underwent allo HSCT at the VU/VA SCT program. Variables including donor type, stem cell source, regimen intensity, and degree of HLA matching were analyzed for their effect on OS and TTP. Median age at transplant was 47 (19–66). 85 pts (91%) had poor risk disease, defined as prior MDS or MPD (n = 17), poor-risk cytogenetics (n = 6), refractory disease (n = 4), relapsed disease (n = 15), history of chemotherapy and/or radiotherapy for a prior malignancy (n = 4), CR2 (n = 35), or requiring >1 cycle of induction to achieve CR1 (n = 4). Regimens were either full-dose (BuCy and CyTBI) or reduced-dose (FluBu, FluBuTBI, or FluTBI). Of the 93 pts, 62 (67%) had matched related donors (MRD) and 31 (33%) had unrelated donors (URD). Both groups (MRD vs URD) were similar in disease risk (87% vs 100% high risk), degree of HLA matching (98% vs 77% fully matched), and regimen intensity (79% vs 77% full-dose) but differed significantly in stem cell source with MRD 95% PBSC and URD 71% BM, P < .001. Day 100 mortality was 11% for MRD versus 29% for URD, and all pts surviving to day 30 engrafted (ANC >500). Median OS was 10.8 months and was not significantly affected by donor type, regimen intensity, or pt age. OS was significantly higher in pts with fully-matched donors (median 12.9 months vs 2.4 mos, P = .027) and in pts without high-risk disease (median not reached vs 8.0 months, P = .040). There was also a trend towards improved survival of pts receiving PBSC versus BM (median 13.4 mos vs 6.7, P = .062). Interestingly, pts receiving full-dose regimens were more likely to die of relapse than transplant-related mortality (TRM) (30 relapse vs 16 TRM), while pts receiving reduced-dose regimens had more TRM than relapse deaths (3 relapse vs 9 TRM, P = .02), which may be accounted for by the higher median age of the reduced-dose group (56 vs 43). Of the 93 pts, 35 (38%) are alive with a median follow-up of 18.0 mos (5.5–61.8), 35 (38%) have died of relapse, and 23 (25%) TRM. TTP was 31.4 months with censorship of pts with TRM. OS at 36 months was 33%. Using a Cox-proportional multivariate model, only disease risk approached significance with a hazard ratio of 3.6 (P = .079). These results highlight the need for better anti-leukemic regimens and indicate that allo HSCT is most beneficial to pts who have chemotherapy-responsive disease and few risk factors for TRM, but can still salvage approximately 1/3 of patients with poor risk disease.