Outcomes of older patients aged 60 to 70 years undergoing reduced intensity transplant for acute myeloblastic leukemia: results of the NCRI acute myeloid leukemia 16 trial

Reduced Intensity Conditioning (RIC) transplantation is increasingly offered to older patients with acute myeloblastic leukemia (AML). We have previously shown that a RIC allograft, particularly from a sibling donor is beneficial in intermediate risk patients aged 35-65 years. We here present analyses from the NCRI AML16 trial extending this experience to older patients aged 60-70 inclusive lacking favorable risk cytogenetics 932 patients were studied, with RIC transplant in first remission given to 144 (sibling n=52, MUD n=92) with median follow-up for survival from CR of 60 months. Comparisons of transplant versus not are carried out using Mantel-Byar analysis. Among the 144 allografts, 93 had intermediate risk cytogenetics, 18 adverse and 33 were unknown. In transplanted patients survival was 37% at 5 years, and while the survival for siblings (44%) was better than that for MUDs (34%) this was not significant (p=0.2). When comparing RIC versus chemotherapy survival was significantly improved (37% vs 20%, HR 0.67 (0.53-0.84) p<0.001). When stratified by Wheatley risk group into good, standard and poor risk there was consistent benefit for RIC across risk groups. When stratified by post course-1 flow MRD status there was consistent benefit for allograft. The benefit for RIC was seen in patients with a FLT3 ITD or NPM1 mutation with no evidence of a differential effect by genotype. We conclude that RIC transplant is an attractive option for older AML patients lacking favorable risk cytogenetics and in this study, we could not find a group that did not benefit.