[Minimal residual disease in adults with Philadelphia chromosome negative acute lymphoblastic leukemia in high-risk]

Objective: To explore the significance of minimal residual disease (MRD) in predicting prognosis and guiding therapy of adults with Philadelphia-chromosome negative acute lymphoblastic leukemia (Ph(-) ALL) in high-risk. Methods: Data of newly diagnosed adults with Ph(-) ALL in high-risk who achieved CR were reviewed. Variables associated with outcome were identified by COX regression model and Landmark analysis. Results: A total of 177 patients, 99 (56%) cases male with a median age of 40 years (range, 16-65 years) were included in this study. Of them, 95 (54%) patients received allo-HSCT in CR(1). Multivariate analyses showed that MRD negativity after the first cycle of consolidation (HR=0.52, 95%CI 0.30-0.89, P=0.017) and achieving CR within 4 weeks (HR=0.43, 95%CI 0.24-0.79, P=0.006) were the factors significantly-associated with longer DFS, and allo-HSCT was associated with both longer DFS (HR=0.13, 95%CI 0.08-0.22, P<0.001) and OS (HR=0.24, 95%CI 0.15-0.41, P<0.001) . Landmark analysis was performed on 121 patients, of 85 patients achieving MRD negativity after the first cycle of consolidation, multivariate analyses showed that MRD negativity after the third cycle of consolidation was significantly-associated with longer DFS (HR=0.18, 95%CI 0.05-0.64, P=0.008) and OS (HR=0.14, 95%CI 0.04-0.50, P=0.003) . For the patients achieving MRD negativity after both the first and the third cycles of consolidation, the 3-year DFS rate in the allo-HSCT cohort had a higher trend compared with that in the chemotherapy cohort (75.2% vs 51.3%, P=0.082) , however, the 3-year OS rates in the 2 cohorts were similar (72.7% vs 68.7%, P=0.992) . In those with MRD positivity after the first and/or the third cycle of consolidation, 3-year DFS (64.8% vs 33.3%, P=0.006) and OS (77.0% vs 33.3%, P=0.028) rates in the allo-HSCT cohort were significantly higher than those in the chemotherapy cohort, and similar to those in the cohort achieving MRD negativity after both the first and the third cycles of consolidation and receiving allo-HSCT. Conclusions: MRD negativity after the first cycle of consolidation was a predictor for better outcome in adults with Ph(-) ALL in high-risk. The survival advantage of the allo-HSCT cohort was not pronounced compared with that in the chemotherapy cohort even in those with high-risk features but achieving MDR negativity after both the first and third cycles of consolidation. However, allo-HSCT could be a good option for the patients with MRD positivity after the first and/or the third cycle of consolidation.