Status of minimal residual disease determines outcome of autologous hematopoietic SCT in adult ALL.

The role of autologous hematopoietic SCT (autoHSCT) in the treatment of high-risk (HR) adult ALL is controversial. In this study, we retrospectively analyzed the results of autoHSCT according to the status of minimal residual disease (MRD) at transplantation, as a joint analysis of the European Study Group for Adult ALL (EWALL). Data on 123 recipients of autoHSCT, aged 31 (16-59) years, with B-lineage (n=77) or T-lineage (n=46) ALL were included. In a cohort of Ph-negative ALL, the probability of leukemia-free survival at 5 years was higher for patients with MRD <0.1% compared with those with MRD > or = 0.1% (57 vs 17%, P=0.0002). The difference was significant for T-lineage ALL (62 vs 8%, P=0.001), and a tendency was observed for B-lineage ALL (54 vs 26%, P=0.17). In a multivariate analysis, adjusted for other potential prognostic factors, high MRD level remained the only independent factor associated with increased risk of failure (risk ratio, 2.8; P=0.0005). We conclude that MRD determines the outcome of autoHSCT in HR adult ALL. Our results suggest the need to reevaluate the role of this treatment option in prospective trials.