Yue-Yun Lai

MRD-directed risk stratification treatment may improve outcomes of t(8;21) AML in the first complete remission: results from the AML05 multicenter trial

We aimed to improve the outcome of t(8;21) acute myeloid leukemia (AML) in the first complete remission (CR1) by applying risk-directed therapy based on minimal residual disease (MRD) determined by RUNX1/RUNX1T1 transcript levels. Risk-directed therapy included recommending allogeneic hematopoietic stem cell transplantation (allo-HSCT) for high-risk patients and chemotherapy/autologous-HSCT (auto-HSCT) for low-risk patients. Among 116 eligible patients, MRD status after the second consolidation rather than induction or first consolidation could discriminate high-risk relapse patients (P = .001). Allo-HSCT could reduce relapse and improve survival compared with chemotherapy for high-risk patients (cumulative incidence of relapse [CIR]: 22.1% vs 78.9%, P < .0001; disease-free survival [DFS]: 61.7% vs 19.6%, P = .001), whereas chemotherapy/auto-HSCT achieved a low relapse rate (5.3%) and high DFS (94.7%) for low-risk patients. Multivariate analysis revealed that MRD status and treatment choice were independent prognostic factors for relapse, DFS, and OS. We concluded that MRD status after the second consolidation may be the best timing for treatment choice. MRD-directed risk stratification treatment may improve the outcome of t(8;21) AML in CR1. This trial was registered at http://www.chictr.org as #ChiCTR-OCH-12002406.

Imatinib mesylate versus allogeneic hematopoietic stem cell transplantation for patients with chronic myelogenous leukemia in the accelerated phase

The relative merits of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and imatinib for chronic myelogenous leukemia in the accelerated phase (AP-CML) have not previously been evaluated. This cohort study was designed to compare the outcomes of imatinib (n = 87) versus allo-HSCT (n = 45) for AP-CML. A multivariate analysis of the total population revealed that a CML duration ≥ 12 months, hemoglobin < 100 g/L, and peripheral blood blasts ≥ 5% were independent adverse prognostic factors for both overall survival (OS) and progression-free survival (PFS). Both treatments resulted in similar survival in low-risk (no factor) patients, with 6-year event-free survival (EFS), OS, and PFS rates of more than 80.0%. Intermediate-risk (any factor) patients showed no difference in EFS and OS, but 6-year PFS rates were 55.7% versus 92.9% (P = .047) with imatinib versus allo-HSCT, respectively. Among high-risk (at least 2 factors) patients, imatinib was by far inferior to allo-HSCT, with 5-year EFS, OS, and PFS rates of 9.3% versus 66.7% (P = .034), 17.7% versus 100% (P = .008), and 18.8% versus 100% (P = .006), respectively. We conclude that allo-HSCT confers significant survival advantages for high- and intermediate-risk patients with AP-CML compared with imatinib treatment; however, the outcomes of the 2 therapies are equally good in low-risk patients. All trials were registered with the Chinese Clinical Trial Registry (www.chictr.org) as CHiCTR-TNC-10000955.

Characteristics of BCR–ABL kinase domain point mutations in Chinese imatinib-resistant chronic myeloid leukemia patients

To explore the characteristics of BCR–ABL kinase domain point mutations in Chinese chronic myeloid leukemia (CML) patients, a cohort of 127 patients with hematologic or cytogenetic resistance to imatinib are screened by direct sequencing. Mutations are found in 74 patients (58%). More patients with hematologic resistance show mutations compared to patients with cytogenetic resistance (70% vs 44%, p = 0.002), and more patients with acquired resistance present mutations compared to patients with primary resistance (68% vs 48%, p = 0.031). Frequencies of mutations were similar in early chronic phase (ECP), late chronic phase (LCP), accelerated phase, and blast phase (BP) patients (56%, 58%, 50%, and 69%, respectively; p > 0.05). Overall, 25 mutants are found in 21 amino acid sites, and four of them (I418V, E450A, E453L, and E455K) are first reported here. All patients with these four mutants either progress to or reenter the BP. The most frequent mutant is M244V, followed by Y253H, F359C/V/I, G250E, E255K, and T315I. Only seven patients (9%) have T315I mutants, and all showed hematologic resistance. Three of them were in the ECP and three in the LCP. Look-back studies show that mutants were detected 0–20 (median 7) months ahead of the appearance of clinical resistance in 15 tested patients with acquired resistance. ABL mutations are common in Chinese imatinib-resistant CML patients and are associated with clinical resistance. Chinese patients also seem to have unique profiles in the types and frequencies of some mutants, the disease phases of patients with T315I mutation, and the frequency of mutations in CP patients.

Prevalence and prognostic significance of c-KIT mutations in core binding factor acute myeloid leukemia: A comprehensive large-scale study from a single Chinese center

To clarify the prevalence and prognostic significance of c-KIT mutations in patients with core binding factor acute myeloid leukemia (CBF-AML), a total of 351 patients who were categorized as pediatric t(8;21), adult t(8;21), pediatric inv(16), or adult inv(16) were screened at diagnosis for c-KIT mutations in exons 17 and 8 using direct sequencing. A total of 250 patients underwent follow-up. Overall, 36.5% of the patients had a c-KIT mutation. Adult t(8;21) and inv(16) patients had mutations predominantly in exons 17 and 8, respectively. Higher White blood cell (WBC) count, WBC index, and AML1-ETO transcript levels in adult t(8;21) patients were significantly associated with c-KIT mutations and mutations in exon 17 (P≤0.030). c-KIT mutations in adult t(8;21) patients were significantly correlated with a high cumulative incidence of relapse (CIR, P=0.0070) at 2 years and a low 2-year disease-free survival (DFS, P=0.013) and overall survival (OS, P=0.0055). However, no significant difference was revealed in the effect of c-KIT mutations on outcome of adult inv(16) and pediatric t(8;21) patients (all P>0.05). Multivariate analysis revealed that c-KIT mutation is an independent prognostic factor for relapse, DFS, and OS (P≤0.016) in adult t(8;21) AML patients. Therefore, with regard to c-KIT mutation, CBF-AML is a heterogeneous disease. c-KIT mutations have a strong adverse effect on the relapse and survival of adult t(8;21) AML patients.

CXCR4 is a good survival prognostic indicator in multiple myeloma patients

SDF-1α and its receptor CXCR4 are involved in multiple myeloma (MM) by attracting and activating plasma cells in the bone marrow. CXCR4 expression in MM cells is inversely correlated with disease activity. The aim of this study was to evaluate CXCR4 as a prognostic tool in MM, as well as other markers of disease, such as chromosomal aberrancies. Purpose was to investigate the expression levels of SDF-1α before and after bortezomib and thalidomide treatment. From February 2006 to April 2012, CXCR4 expression was prospectively assessed in bone marrow samples from a large population of patients (n=227) using flow cytometry. Clinical characteristics were collected and chromosomal aberrancies were assessed in 144 patients. SDF-1α levels were determined using ELISA in peripheral blood samples from 40 patients before and after chemotherapy. Our results show that CXCR4 was present in 43.2% (98/227) of newly diagnosed MM patients and that CXCR4 expression was significantly correlated with CD117 (P<0.05). CXCR4-positive MM patients had a significantly longer estimated survival time than CXCR4-negative patients (median of 48 vs. 42 months, P<0.05). Multivariate survival analyses identified that the +1q21/CXCR4- phenotype is an independent survival predictor, along with the International Staging System (ISS) stage. No significant difference was observed in expression levels of SDF-1α before and after bortezomib/thalidomide treatment. In conclusion, +1q21/CXCR4- could be an independent survival prognosis predictor in MM patients. Expression levels of SDF-1α before and after bortezomib/thalidomide treatment are not different, although they are higher than in controls.

NPM1-mutated acute myeloid leukemia of monocytic or myeloid origin exhibit distinct immunophenotypes.

Acute myeloid leukemia with mutated nucleophosmin (NPM1m+AML) is a heterogeneous entity. We investigated whether NPM1m+AML with monocytic or myeloid differentiation have distinct immunophenotype. The study included 160 NPM1m+AMLpatients and 178 AML patients without NPM1 mutation and recurrent cytogenetic abnormality (NPM1wt-AML). We analyzed the immunophenotype by flow cytometry. NPM1 mutation was detected by PCR. Compared with NPM1wt-AML patients, NPM1m+AML patients showed higher positive rates of CD33 and CD9 and lower positive rates of CD34, HLA-DR, CD7, CD15 and CD117 (all P<0.05). HLA-DR, CD64, CD14, CD11b, CD15, CD4, CD9 and CD10 were higher (P<0.001) and CD117 was lower (P<0.01) in monocytic NPM1m+AML compared with myeloid NPM1m+AML. Similar rates of lymphoid antigen (CD19, CD2, and CD7) and myeloid antigen (CD13, CD33) positivity were detected in monocytic and myeloid NPM1m+AML. Compared with NPM1wt-AML, CD34 expression was lower both in myeloid and monocytic NPM1m+AML subgroups, although HLA-DR was lower in NPM1m+AML compared with NPM1wt-AML only in myeloid subgroup. Comparisons of NPM1m+AML and NPM1wt-AML showed no differences in monocyte-associated markers such as CD14 and CD11b in myeloid and monocytic subgroup. Myeloid NPM1m+AML correlated with the female gender (P=0.001), lower WBC counts (P=0.04) and higher WT1 transcripts (P=0.006) compared with monocytic NPM1m+AML.These results suggested monocytic and myeloid-derived NPM1m+AML exhibit distinct immunophenotypes.

Which method better evaluates the molecular response in newly diagnosed chronic phase chronic myeloid leukemia patients with imatinib treatment, BCR-ABLIS or log reduction from the baseline level?

The molecular response of chronic myeloid leukemia (CML) patients to tyrosine kinase inhibitor treatment can be evaluated either by BCR-ABL mRNA levels on international scale (IS) or by log reduction from the baseline level of the laboratory. Both methods were compared in 248 newly diagnosed chronic phase CML patients treated with imatinib. The major molecular responses (MMR) obtained by both methods predict progression-free survival (PFS, all P<0.0001). Thirty-six patients, who were identified as MMR patients by the IS method but as non-MMR patients by the log reduction method, had the same PFS as MMR patients identified by both methods. The molecular responses of patients at 3 and 6 months, as evaluated by the two methods, have similar predictive values on their cytogenetic responses at 12 months and on their molecular responses at 18 months. Both ≤ 10%(IS) and ≥ 1 log reduction at 3 months and ≤ 1%(IS) at 6 months were significantly associated with PFS (P=0.0011, 0.0090, and 0.0064). The percentages of patients with BCR-ABL(IS) of ≤ 1%, >1-10%, and of >10% at 3 months and 6 months in the German CML Study IV were similar with those with corresponding BCR-ABL(IS) in our center, but was significantly different with those evaluated by the log reduction method. Therefore, the molecular response evaluated by BCR-ABL(IS) has similar trends in PFS and in response prediction, but can better differentiate patients than that by the log reduction method. Furthermore, the IS method allows comparison among molecular response results from different laboratories.

PRAME and WT1 transcripts constitute a good molecular marker combination for monitoring minimal residual disease in myelodysplastic syndromes

Abstract PRAME and WT1 transcript levels were simultaneously measured in 312 bone marrow samples collected from patients with newly diagnosed myelodysplastic syndromes (MDS) and 111 samples collected during the treatment of 17 patients. Both the positive rate and the > 1-log increase expression frequency of PRAME were similar to those of WT1 (74.4 % vs. 77.6%; 51.6% vs. 49.0%), and 88.1% of patients overexpressed at least one marker. Moreover, the frequencies of PRAME expression with higher degrees of increase were significantly higher compared with those of WT1 expression (> 2-log increase: 30.8% vs. 3.8%; > 3-log increase: 9.0% vs. 0%; all p < 0.001). PRAME had a higher log increase than WT1 in 53.3% of the patients with overexpressed WT1. Both PRAME and WT1 transcript levels generally fluctuated within the normal range after hematopoietic stem cell transplant in all 10 patients in continuous complete remission. Six out of seven patients were predicted relapse by the combined detection: sustained positivity, or significant increase to be positive for both WT1 and PRAME in three patients, earlier by PRAME than WT1 or by PRAME alone in three patients. Thus, PRAME and WT1 transcripts constitute a good molecular marker combination for monitoring minimal residual disease in MDS.

The differences and correlations of BCR-ABL transcripts between peripheral blood and bone marrow assays are associated with the molecular responses in the bone marrow for chronic myelogenous leukemia.

Previous studies concerning BCR‐ABL mRNA levels by quantitative real‐time RT‐PCR (Q‐PCR) for chronic myelogenous leukemia (CML) have shown a significant concordance between peripheral blood (PB) and bone marrow (BM) assays. The objective of this study was to determine whether molecular monitoring using PB was comparable to using BM for CML. A comparative study was performed that analyzed the Q‐PCR results of 712 simultaneous PB and BM samples from 330 patients before and during imatinib therapy. For the 78 paired pretreatment samples, the level of BCR‐ABL mRNA in PB was lower than that in BM (P = 0.007). Although the overall amounts of BCR‐ABL mRNA in the PB and BM were comparable (P= 0.072) and there was a strong correlation (r = 0.839, P < 0.001) with the 634 paired on‐treatment samples, the depth of the molecular response in PB was lower than that in BM (P < 0.001). The level of BCR‐ABL mRNA in PB was lower than that in BM where the BM BCR‐ABL mRNA < 1 log reduction (P < 0.001) or ≥ 1–< 2 log‐reductions (P = 0.008) from the baseline, and higher than that where the BM BCR‐ABL mRNA ≥ 2 log‐reductions (P < 0.001). A strong correlation (r = 0.811, P < 0.001) was only found where the BM BCR‐ABL mRNA < 1 log reduction. We conclude that the differences and correlations of BCR‐ABL mRNA between PB and BM assays depend on the depth of the molecular response in BM for CML during imatinib therapy. Am. J. Hematol., 2012.

Atorvastatin enhances bone marrow endothelial cell function in corticosteroid-resistant immune thrombocytopenia patients

The pathogenesis of corticosteroid-resistant immune thrombocytopenia (ITP), a clinically challenging condition in which patients exhibit either no response to corticosteroids or are corticosteroid-dependent, remains poorly understood. Murine studies suggest that bone marrow (BM) endothelial progenitor cells (EPCs) play a crucial role in regulating megakaryocytopoiesis. However, little is known regarding the number and function of BM EPCs or how to improve impaired BM EPCs in corticosteroid-resistant ITP patients. In the current case-control study, we evaluated whether the BM EPCs in corticosteroid-resistant ITP differed from those in corticosteroid-sensitive ITP. Moreover, whether atorvastatin could enhance the number and function of BM EPCs derived from corticosteroid-resistant ITP patients was investigated in vitro and in vivo. Reduced and dysfunctional BM EPCs, characterized by decreased capacities of migration and angiogenesis as well as higher levels of reactive oxygen species and apoptosis, were observed in corticosteroid-resistant ITP patients. In vitro treatment with atorvastatin quantitatively and functionally improved BM EPCs derived from corticosteroid-resistant ITP patients by downregulating the p38 MAPK pathway and upregulating the Akt pathway, and rescued the impaired BM EPCs to support megakaryocytopoiesis. Subsequently, a pilot cohort study showed that atorvastatin was safe and effective in corticosteroid-resistant ITP patients. Taken together, these results indicate that reduced and dysfunctional BM EPCs play a role in the pathogenesis of corticosteroid-resistant ITP, and the impaired BM EPCs could be improved by atorvastatin both in vitro and in vivo. Although requiring further validation, our data indicate that atorvastatin represents a promising therapeutic approach for repairing impaired BM EPCs in corticosteroid-resistant ITP patients.