Inferior Outcome of Addition of the Aminopeptidase Inhibitor Tosedostat to Standard Intensive Treatment for Elderly Patients with AML and High Risk MDS.

Treatment results of AML in elderly patients are unsatisfactory. We hypothesized that addition of tosedostat, an aminopeptidase inhibitor, to intensive chemotherapy may improve outcome in this population. After establishing a safe dose in a run-in phase of the study in 22 patients, 231 eligible patients with AML above 65 years of age (median 70, range 66-81) were randomly assigned in this open label randomized Phase II study to receive standard chemotherapy (3+7) with or without tosedostat at the selected daily dose of 120 mg (n = 116), days 1-21. In the second cycle, patients received cytarabine 1000 mg/m2 twice daily on days 1-6 with or without tosedostat. CR/CRi rates in the 2 arms were not significantly different (69% (95% C.I. 60-77%) vs 64% (55-73%), respectively). At 24 months, event-free survival (EFS) was 20% for the standard arm versus 12% for the tosedostat arm (Cox-p = 0.01) and overall survival (OS) 33% vs 18% respectively (p = 0.006). Infectious complications accounted for an increased early death rate in the tosedostat arm. Atrial fibrillation was more common in the tosedostat arm as well. The results of the present study show that the addition of tosedostat to standard chemotherapy does negatively affect the therapeutic outcome of elderly AML patients.

Therapeutic value of clofarabine in younger and middle-aged (18-65 years) adults with newly diagnosed AML.

Clofarabine has demonstrated antileukemic activity in acute myeloid leukemia (AML) but has yet to be critically evaluated in younger adults in the frontline with standard chemotherapy. We compared 2 induction regimens in newly diagnosed patients ages 18 to 65 with acute myeloid leukemia (AML)/high-risk myelodysplastic syndromes, that is, idarubicine-cytarabine (cycle I) and amsacrine-cytarabine (cycle II) without or with clofarabine (10 mg/m2 on days 1-5 of each of both cycles). Consolidation involved chemotherapy with or without hematopoietic stem cell transplantation. Event-free survival (EFS, primary endpoint) and other clinical endpoints and toxicities were assessed. We randomized 402 and 393 evaluable patients to the control or clofarabine induction treatment arms. Complete remission rates (89%) did not differ but were attained faster with clofarabine (66% vs 75% after cycle I). Clofarabine added grades 3 to 4 toxicities and delayed hematological recovery. At a median follow-up of 36 months, the study reveals no differences in overall survival and EFS between the control (EFS, 35% ± 3 [standard error] at 4 years) and clofarabine treatments (38% ± 3) but a markedly reduced relapse rate (44% ± 3 vs 35% ± 3) in favor of clofarabine and an increased death probability in remission (15% ± 2 vs 22% ± 3). In the subgroup analyses, clofarabine improved overall survival and EFS for European Leukemia Net (ELN) 2010 intermediate I prognostic risk AML (EFS, 26% ± 4 vs 40% ± 5 at 4 years; Cox P = .002) and for the intermediate risk genotype NPM1 wild-type/FLT3 without internal-tandem duplications (EFS, 18% ± 5 vs 40% ± 7; Cox P < .001). Clofarabine improves survival in subsets of intermediate-risk AML only. HOVON-102 study is registered at Netherlands Trial Registry #NTR2187.

Graft-Versus-Leukemia Effect of Allogeneic Stem-Cell Transplantation and Minimal Residual Disease in Patients With Acute Myeloid Leukemia in First Complete Remission.

PURPOSE: The detection of minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) may improve future risk-adapted treatment strategies. We assessed whether MRD-positive and MRD-negative patients with AML benefit differently from the graft-versus-leukemia effect of allogeneic hematopoietic stem-cell transplantation (alloHSCT). METHODS: A total of 1,511 patients were treated in subsequent Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research AML trials, of whom 547 obtained a first complete remission, received postremission treatment (PRT), and had available flow cytometric MRD before PRT. MRD positivity was defined as more than 0.1% cells with a leukemia-associated immunophenotype within the WBC compartment. PRT consisted of alloHSCT (n = 282), conventional PRT by a third cycle of chemotherapy (n = 160), or autologous hematopoietic stem-cell transplantation (n = 105). RESULTS: MRD was positive in 129 patients (24%) after induction chemotherapy before proceeding to PRT. Overall survival and relapse-free survival were significantly better in patients without MRD before PRT compared with MRD-positive patients (65% ± 2% v 50% ± 5% at 4 years; P = .002; and 58% ± 3% v 38% ± 4%; P < .001, respectively), which was mainly because of a lower cumulative incidence of relapse (32% ± 2% compared with 54% ± 4%; P < .001, respectively). Multivariable analysis with adjustment for covariables showed that the incidence of relapse was significantly reduced after alloHSCT compared with chemotherapy or autologous hematopoietic stem cell transplantation (hazard ratio [HR], 0.36; P < .001), which was similarly exerted in both MRD-negative and MRD-positive patients (HR, 0.38; P < .001; and HR, 0.35; P < .001, respectively). CONCLUSION: The graft-versus-leukemia effect of alloHSCT is equally present in MRD-positive and MRD-negative patients, which advocates a personalized application of alloHSCT, taking into account the risk of relapse determined by AML risk group and MRD status, as well as the counterbalancing risk of nonrelapse mortality.