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 CR₁. 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.

Angiogenesis is an essential process in tumor growth, invasion and metastasis. VEGF receptor 2 (VEGFR2) inhibitors targeting tumor angiogenic pathway have been widely used in the clinical cancer treatment. However, most of currently used VEGFR2 kinase inhibitors are multi-target inhibitors which might result in target-associated side effects and therefore limited clinical toleration. Highly selective VEGFR inhibitors are still highly demanded from both basic research and clinical application point of view. Here we report the discovery and characterization of a novel VEGFR2 inhibitor (CHMFL-VEGFR2-002), which exhibited high selectivity among structurally closed kinases including PDGFRs, FGFRs, CSF1R, etc. CHMFL-VEGFR2-002 displayed potent inhibitory activity against VEGFR2 kinase in the biochemical assay (IC = 66 nmol/L) and VEGFR2 autophosphorylation in cells (ECs ∼100 nmol/L) as well as potent anti-proliferation effect against VEGFR2 transformed BaF3 cells (GI = 150 nmol/L). In addition, CHMFL-VEGFR2-002 also displayed good anti-angiogenesis efficacy and exhibited good PK (pharmacokinetics) profile with bioavailability over 49% and anti-angiogenesis efficacy in both zebrafish and mouse models without apparent toxicity. These results suggest that CHMFL-VEGFR2-002 might be a useful research tool for dissecting new functions of VEGFR2 kinase as well as a potential anti-angiogenetic agent for the cancer therapy.