Toru Sakura

Comprehensive analysis of genetic alterations and their prognostic impacts in adult acute myeloid leukemia patients.

To clarify the cooperative roles of recurrently identified mutations and to establish a more precise risk classification system in acute myeloid leukemia (AML), we comprehensively analyzed mutations in 51 genes, as well as cytogenetics and 11 chimeric transcripts, in 197 adult patients with de novo AML who were registered in the Japan Adult Leukemia Study Group AML201 study. We identified a total of 505 mutations in 44 genes, while only five genes, FLT3, NPM1, CEBPA, DNMT3A and KIT, were mutated in more than 10% of the patients. Although several cooperative and exclusive mutation patterns were observed, the accumulated mutation number was higher in cytogenetically normal AML and lower in AML with RUNX1-RUNX1T1 and CBFB-MYH11, indicating a strong potential of these translocations for the initiation of AML. Furthermore, we evaluated the prognostic impacts of each sole mutation and the combinations of mutations and/or cytogenetics, and demonstrated that AML patients could be clearly stratified into five risk groups for overall survival by including the mutation status of DNMT3A, MLL-PTD and TP53 genes in the risk classification system of the European LeukemiaNet. These results indicate that the prognosis of AML could be stratified by the major mutation status in combination with cytogenetics.

A randomized comparison of 4 courses of standard-dose multiagent chemotherapy versus 3 courses of high-dose cytarabine alone in postremission therapy for acute myeloid leukemia in adults: the JALSG AML201 Study

We conducted a prospective randomized study to assess the optimal postremission therapy for adult acute myeloid leukemia in patients younger than 65 years in the first complete remission. A total of 781 patients in complete remission were randomly assigned to receive consolidation chemotherapy of either 3 courses of high-dose cytarabine (HiDAC, 2 g/m(2) twice daily for 5 days) alone or 4 courses of conventional standard-dose multiagent chemotherapy (CT) established in the previous JALSG AML97 study. Five-year disease-free survival was 43% for the HiDAC group and 39% for the multiagent CT group (P = .724), and 5-year overall survival was 58% and 56%, respectively (P = .954). Among the favorable cytogenetic risk group (n = 218), 5-year disease-free survival was 57% for HiDAC and 39% for multiagent CT (P = .050), and 5-year overall survival was 75% and 66%, respectively (P = .174). In the HiDAC group, the nadir of leukocyte counts was lower, and the duration of leukocyte less than 1.0 × 10(9)/L longer, and the frequency of documented infections higher. The present study demonstrated that the multiagent CT regimen is as effective as our HiDAC regimen for consolidation. Our HiDAC regimen resulted in a beneficial effect on disease-free survival only in the favorable cytogenetic leukemia group. This trial was registered at www.umin.ac.jp/ctr/ as #C000000157.

Prognostic factors and outcomes of adult patients with acute myeloid leukemia after first relapse

Background Patients with acute myeloid leukemia who are treated with conventional chemotherapy still have a substantial risk of relapse; the prognostic factors and optimal treatments after relapse have not been fully established. We, therefore, retrospectively analyzed data from patients with acute myeloid leukemia who had achieved first complete remission to assess their prognosis after first relapse. Design and Methods Clinical data were collected from 70 institutions across the country on adult patients who were diagnosed with acute myeloid leukemia and who had achieved a first complete remission after one or two courses of induction chemotherapy. Results Among the 1,535 patients who were treated with chemotherapy alone, 1,015 relapsed. Half of them subsequently achieved a second complete remission. The overall survival was 30% at 3 years after relapse. Multivariate analysis showed that achievement of second complete remission, salvage allogeneic hematopoietic cell transplantation, and a relapse-free interval of 1 year or longer were independent prognostic factors. The outcome after allogeneic transplantation in second complete remission was comparable to that after transplantation in first complete remission. Patients with acute myeloid leukemia and cytogenetic risk factors other than inv(16) or t(8;21) had a significantly worse outcome when they did not undergo salvage transplantation even when they achieved second complete remission. Conclusions We found that both the achievement of second complete remission and the application of salvage transplantation were crucial for improving the prognosis of patients with acute myeloid leukemia in first relapse. Our results indicate that the optimal treatment strategy after first relapse may differ according to the cytogenetic risk.

Myeloablative allogeneic hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia in adults: significant roles of total body irradiation and chronic graft-versus-host disease.

Summary:Disease-free survival in Philadelphia chromosome-positive ALL (Ph+ALL) is very poor, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently considered the only procedure with curative potential. To identify factors affecting transplant outcome, we analyzed the data from 197 Ph+ALL patients aged 16 years or older who had undergone allo-HSCT. The 5-year survival rates were 34% for patients in first complete remission (CR), 21% for those in second or subsequent CR, and 9% for those with active disease (P<0.0001). Multivariate analysis showed four pre-transplant factors as significantly associated with better survival: younger age, CR at the time of transplantation, conditioning with total body irradiation, and HLA-identical sibling donor (P<0.0001, P<0.0001, P=0.0301, P=0.0412, respectively). Severe acute GVHD increased the risk of treatment-related mortality (TRM) without diminishing the risk of relapse, whereas chronic GVHD reduced the risk of relapse without increasing the risk of TRM. Thus, patients who developed extensive chronic GVHD had better survivals (P=0.0217), and those who developed grade III–IV acute GVHD had worse survivals (P=0.0023) than did the others.

Recurrent DUX4 fusions in B cell acute lymphoblastic leukemia of adolescents and young adults

The oncogenic mechanisms underlying acute lymphoblastic leukemia (ALL) in adolescents and young adults (AYA; 15–39 years old) remain largely elusive. Here we have searched for new oncogenes in AYA-ALL by performing RNA-seq analysis of Philadelphia chromosome (Ph)-negative AYA-ALL specimens (n = 73) with the use of a next-generation sequencer. Interestingly, insertion of D4Z4 repeats containing the DUX4 gene into the IGH locus was frequently identified in B cell AYA-ALL, leading to a high level of expression of DUX4 protein with an aberrant C terminus. A transplantation assay in mice demonstrated that expression of DUX4-IGH in pro-B cells was capable of generating B cell leukemia in vivo. DUX4 fusions were preferentially detected in the AYA generation. Our data thus show that DUX4 can become an oncogenic driver as a result of somatic chromosomal rearrangements and that AYA-ALL may be a clinical entity distinct from ALL at other ages.

A Phase I study to assess the safety, pharmacokinetics and efficacy of barasertib (AZD1152), an Aurora B kinase inhibitor, in Japanese patients with advanced acute myeloid leukemia.

Barasertib (AZD1152) is a highly potent and selective Aurora B kinase inhibitor. The safety, efficacy and pharmacokinetic (PK) profile of barasertib were investigated in Japanese patients with advanced acute myeloid leukemia. Barasertib (50-1200mg) was administered as a continuous 7-day intravenous infusion every 21 days. No dose-limiting toxicities were reported and barasertib 1200mg was chosen for further evaluation in Japanese patients. Neutropenia and febrile neutropenia were the most commonly reported adverse events. The PK profile was similar to Western patients. A promising overall hematologic response rate of 19% was achieved, which warrants further investigation in these patients.

Markedly improved outcomes and acceptable toxicity in adolescents and young adults with acute lymphoblastic leukemia following treatment with a pediatric protocol: a phase II study by the Japan Adult Leukemia Study Group

The superiority of the pediatric protocol for adolescents with acute lymphoblastic leukemia (ALL) has already been demonstrated, however, its efficacy in young adults remains unclear. The ALL202-U protocol was conducted to examine the efficacy and feasibility of a pediatric protocol in adolescents and young adults (AYAs) with BCR–ABL-negative ALL. Patients aged 15–24 years (n=139) were treated with the same protocol used for pediatric B-ALL. The primary objective of this study was to assess the disease-free survival (DFS) rate and its secondary aims were to assess toxicity, the complete remission (CR) rate and the overall survival (OS) rate. The CR rate was 94%. The 5-year DFS and OS rates were 67% (95% confidence interval (CI) 58–75%) and 73% (95% CI 64–80%), respectively. Severe adverse events were observed at a frequency that was similar to or lower than that in children treated with the same protocol. Only insufficient maintenance therapy significantly worsened the DFS (hazard ratio 5.60, P<0.001). These results indicate that this protocol may be a feasible and highly effective treatment for AYA with BCR–ABL-negative ALL.

A decision analysis of allogeneic hematopoietic stem cell transplantation in adult patients with Philadelphia chromosome-negative acute lymphoblastic leukemia in first remission who have an HLA-matched sibling donor

Clinical studies using genetic randomization cannot accurately answer whether adult patients with Philadelphia chromosome-negative acute lymphoblastic leukemia (ALL) who have a human leukocyte antigen (HLA)-matched sibling should undergo allogeneic hematopoietic stem cell transplantation (HSCT) or chemotherapy in first remission, as, in these studies, patients without a sibling donor undergo alternative donor transplantation or chemotherapy alone after a relapse. Therefore, we performed a decision analysis to identify the optimal strategy in this setting. Transition probabilities and utilities were estimated from prospective studies of the Japan Adult Leukemia Study Group, the database of the Japan Society for Hematopoietic Cell Transplantation and the literature. The primary outcome measure was the 10-year survival probability with or without quality of life (QOL) adjustments. Subgroup analyses were performed according to risk stratification on the basis of white blood cell count and cytogenetics, and according to age stratification. In analyses without QOL adjustments, allogeneic HSCT in first remission was superior in the whole population (48.3 vs 32.6%) and in all subgroups. With QOL adjustments, a similar tendency was conserved (44.9 vs 31.7% in the whole population). To improve the probability of long-term survival, allogeneic HSCT in first remission is recommended for patients who have an HLA-matched sibling.

Tamibarotene As Maintenance Therapy for Acute Promyelocytic Leukemia: Results From a Randomized Controlled Trial

PURPOSE The introduction of all-trans-retinoic acid (ATRA) has significantly improved outcomes for acute promyelocytic leukemia (APL), although a subset of patients still suffer relapse. The purpose of this study was to evaluate the role of maintenance therapy with the synthetic retinoid tamibarotene in APL. PATIENTS AND METHODS Patients with newly diagnosed APL in molecular remission at the end of consolidation therapy were randomly assigned to receive ATRA or tamibarotene, both orally, for 14 days every 3 months for up to 2 years. RESULTS A total of 347 patients were enrolled. Of the 344 eligible patients, 319 (93%) achieved complete remission. After completing three courses of consolidation therapy, 269 patients underwent maintenance random assignment. The relapse-free survival (RFS) rate at 4 years was 84% for the ATRA arm and 91% for the tamibarotene arm (hazard ratio [HR], 0.54; 95% CI, 0.26 to 1.13). When the analysis was restricted to 52 high-risk patients with an initial WBC count ≥ 10.0 × 10(9)/L, the intergroup difference was statistically significant, with 4-year RFS rates of 58% for the ATRA arm and 87% for the tamibarotene arm (HR, 0.26; 95% CI, 0.07 to 0.95). For patients with non-high-risk disease, the HR was 0.82 (95% CI, 0.32 to 2.01). The test for interaction between treatment effects and these subgroups resulted in P = .075. Both treatments were generally well tolerated. CONCLUSION In this trial, no difference was detected between ATRA and tamibarotene for maintenance therapy. In an exploratory analysis, there was a suggestion of improved efficacy of tamibarotene in high-risk patients, but this requires further study.

Clinical significance of granulocytic sarcoma in adult patients with acute myeloid leukemia

To investigate the clinical significance of granulocytic sarcoma (GS) in adults with acute myeloid leukemia (AML), 434 consecutive patients with AML were analyzed retrospectively. Forty‐five patients (10.4%) with GS at diagnosis were younger (P < 0.001), presented with higher white blood cell counts (P = 0.03) and were more likely to conform to French–American–British M4 (P = 0.001) and M5 (P = 0.045) classifications than those without GS. In contrast, no significant difference in frequency of cytogenetic abnormalities was found between the GS and non‐GS groups. Treatment outcomes in 260 patients (40 with GS) who underwent intensive chemotherapy, excluding patients with acute promyelocytic leukemia, were investigated. Complete remission rates did not differ significantly between the GS and non‐GS groups (75.0% vs 79.1%; P = 0.192, respectively) or the 5‐year overall survival (OS) rates (39.9% vs 38.7%; P = 0.749, respectively). However, the GS group had a significantly higher relapse rate than the non‐GS group (74.2% vs 55.3%; P = 0.048) and a significantly lower 5‐year disease‐free survival rate (8.2% vs 25.7%, respectively; P = 0.005). When considered together with the results of multivariate analysis, which identified the presence of GS as an independent predictor for disease‐free survival time, these findings indicate that GS might identify a high‐risk subset of patients with AML. (Cancer Sci, doi: 10.1111/j.1349‐7006.2012.02324.x, 2012)