Addition of cladribine to the standard induction treatment improves outcomes in a subset of elderly acute myeloid leukemia patients. Results of a randomized Polish Adult Leukemia Group (PALG) phase II trial.

Intensive induction chemotherapy using anthracycline and cytarabine backbone is considered the most effective upfront therapy in physically fit older patients with acute myeloid leukemia (AML). However, outcomes of the standard induction in elderly AML are inferior to those observed in younger patients, and they are still unsatisfactory. As addition of cladribine to the standard induction therapy is known to improve outcome in younger AML patients. The present randomized phase II study compares efficacy and toxicity of the DAC (daunorubicin plus cytarabine plus cladribine) regimen with the standard DA (daunorubicin plus cytarabine) regimen in the newly diagnosed AML patients over 60 years of age. A total of 171 patients were enrolled in the study (DA, 86; DAC, 85). A trend toward higher complete remission (CR) was observed in the DAC arm compared to the DA arm (44% vs. 34%; P = .19), which did not lead to improved median overall survival, which in the case of the DAC group was 8.6 months compared to in 9.1 months in the DA group (P = .64). However, DAC appeared to be superior in the group of patients aged 60-65 (CR rate: DAC 51% vs. DA 29%; P = .02). What is more, a subgroup of patients, with good and intermediate karyotypes, benefited from addition of cladribine also in terms of overall survival (P = .02). No differences in hematological and nonhematological toxicity between the DA and DAC regimens were observed.

Prognostic value of inhibitor of apoptosis protein family expression in patients with acute myeloid leukemia.

The inhibitor of apoptosis protein (IAP) family acts as an inhibitor of apoptosis pathways. The potential prognostic value of the expression of selected IAP family members, XIAP, cIAP-1, cIAP-2 and survivin protein, was evaluated with regard to treatment response and survival of 56 newly diagnosed adult patients with acute myeloid leukemia (AML). The presence of these IAP members influenced the achievement of a complete response (CR). In addition, overall survival (OS) was influenced by low survivin expression in univariate and multivariate analysis (p = 0.014 and p = 0.013, respectively). A strong correlation was observed between members of the IAP family (XIAP and cIAP-1, XIAP and cIAP-2, cIAP-1 and cIAP-2, p < 0.001 for all comparisons), while Smac/DIABLO demonstrated an inverse correlation with XIAP, cIAP-1 and cIAP-2 (p < 0.001 for all comparisons). Further studies should be undertaken to better demonstrate the mode of action of IAP members, as well as their prognostic and therapeutic potentials.

Influence of high expression of Smac/DIABLO protein on the clinical outcome in acute myeloid leukemia patients.

The role of the Smac/DIABLO protein, a novel apoptosis agonist, in acute myeloid leukemia (AML) is not clearly determined. The expression of Smac/DIABLO protein in AML leukemic cells and its relationship with clinical outcome was evaluated in this study. The intracellular expression of Smac/DIABLO protein was assessed using multi-color flow cytometry in 71 newly diagnosed AML patients treated with conventional chemotherapy. It was found that the high expression of Smac/DIABLO protein was an independent prognostic factor in terms of higher complete remission rate (p<0.001) and longer overall survival (p=0.003). Moreover the low expression of Smac/DIABLO protein was associated with poor karyotype.

Kinetics and apoptotic profile of circulating endothelial cells as prognostic factors for induction treatment failure in newly diagnosed acute myeloid leukemia patients.

The circulating endothelial cells (CEC) are proposed to be a noninvasive marker of angiogenesis. Recent data suggest that endothelial cells may enhance the survival and proliferation of leukemic blasts and mediate chemotherapy resistance in acute myeloid leukemia (AML). We analyzed CEC count by the four-color flow cytometry in AML and healthy subjects. We evaluated the kinetics of mature CEC, both resting (rCEC) and activated (aCEC), as well as progenitor (CEPC) and apoptotic CEC (CEC(AnnV+)) in AML patients treated with standard chemotherapy and their influence on response to treatment and overall survival. We found significantly higher numbers of aCEC, rCEC, CEPC, and CEC(AnnV+) in AML patients than in healthy controls. The elevated CEPC and absolute blood counts in peripheral blood as well as the low CEC(AnnV+) number were associated with higher probability of induction treatment failure. aCEC, rCEC, CEPC, and CEC(AnnV+) counts determined in complete remission (CR) were significantly lower than those found at diagnosis. In those CR patients, a significant decrease in the CEC count and increase in the number of CEC(AnnV+) were observed already 24h after the first dose of chemotherapy. In refractory AML, the aCEC, rCEC, CEPC, and CEC(AnnV+) counts assessed before and after induction chemotherapy did not differ significantly, and a significant decrease in CEC count and increase in CEC(AnnV+) number were noted only after the last dose of chemotherapy. The number of CEC is significantly higher in AML patients than in healthy subjects and correlates with response to treatment. The evaluation of CEC kinetics and apoptotic profile may be a promising tool to select AML patients with poor response to chemotherapy who may benefit from antiangiogenic therapies.

Cladribine combined with high doses of arabinoside cytosine, mitoxantrone, and G-CSF (CLAG-M) is a highly effective salvage regimen in patients with refractory and relapsed acute myeloid leukemia of the poor risk: a final report of the Polish Adult Leukemia Group.

OBJECTIVES: Patients with primary refractory AML and with early relapses have unfavorable prognoses and require innovative therapeutic approaches. Purine analogs fludarabine (FA) and cladribine (2-CdA) increase cytotoxic effect of Ara-C in leukemic blasts and inhibit DNA repair mechanisms; therefore its association with Ara-C and mitoxantrone (MIT) results in a synergistic effect. In the current report, we present the final results of multi-center phase II study evaluating the efficacy and toxicity of CLAG-M salvage regimen in poor risk refractory/relapsed AML patients. METHODS: The induction chemotherapy consisted of 2-CdA 5 mg/m2, Ara-C 2 g/m2, MIT 10 mg/m2, and granulocyte-colony stimulating factor. In the case of PR, a second CLAG-M was administered. Patients in CR received consolidation courses based on high doses of Ara-C and MIT with or without 2-CdA. RESULTS: One hundred and eighteen patients from 11 centers were registered; 78 primary resistant and 40 relapsed. Sixty-six patients (58%) achieved CR after one or two courses of CLAG-M, 49 (35%) were refractory, and 8 (7%) died early. WBC >10 g/L and age >34 yr were factors associated with increased risk of treatment failure. Hematological toxicity was the most prominent toxicity of this regimen. The probability of OS at 4 yr was 14% (95% CI 4-23%). OS was influenced by age, WBC >10 g/L and poor karyotype in both univariate and multivariate analyses. The probability of 4 yr DFS was 30% for all 66 patients in CR (95% CI 11-49%). Poor karyotype was the only factor associated with decreased probability of DFS. CONCLUSIONS: We conclude that CLAG-M is a well-tolerated and highly effective salvage regimen in poor risk refractory/relapsed AML.

Interaction of doxorubicin and idarubicin with red blood cells from acute myeloid leukaemia patients.

Doxorubicin (DOX) and idarubicin (IDA) are anthracycline antibiotics, widely used in human cancer treatment. The present study addressed the effects of these two drugs on lipid bilayer fluidity, protein conformation and microviscosity in erythrocytes from acute myeloid leukaemia patients, using electron spin resonance (ESR) spectroscopy and fluorescence measurements. Only DOX caused statistically significant changes in the parameters examined. Within 30 min of drug injection, changes were observed in the fluidity of the hydrophobic parts of the lipid bilayer and erythrocyte membrane protein conformation. These changes persisted for up to 24h. Analysis of the EPR Tempamine spectrum also showed that the microviscosity of the erythrocyte interior increased during the early stages of the drug effect. Idarubicin, in contrast, caused no identifiable change in any of the parameters studied and therefore seems to be safe for erythrocytes. We conclude that IDA is markedly less toxic than DOX to erythrocytes from acute myeloid leukaemia patients.

Circulating endothelial cells in patients with acute myeloid leukemia.

OBJECTIVES: The circulating endothelial cells (CEC) are proposed to be a non-invasive marker of angiogenesis. The level of CEC in peripheral blood (PB) of acute myeloid leukemia (AML) patients has not been investigated prior to this study. We evaluated the count of resting (rCEC), activated (aCEC) and endothelial progenitor cells (CEPC) in the PB of AML and healthy subjects. In addition we correlated the levels of CEC with disease status, known prognostic factors and response to treatment. METHODS: CEC were quantified by utilizing four-color flow cytometry procedures in 48 AML patients at the time of diagnosis and 29 healthy controls. Additionally, measurements were again taken after the first course of induction treatment in 12 of the patients. RESULTS: The numbers of aCEC, rCEC and CEPC were significantly higher in the AML patients than in the controls (P < 0.0001, P < 0.0001 and P < 0.001, respectively). The CEC count was significantly higher in the AML patients with white blood cell count (WBC) >15 G/L, elevated lactic dehydrogenase (LDH) levels and a higher (over median) absolute blasts count (ABC) in PB than in the group with WBC <15 G/L (P < 0.03), a normal LDH level (P < 0.03) and a lower (

The interaction of daunorubicin and mitoxantrone with the red blood cells of acute myeloid leukemia patients.

The effect of DNR and MIT on erythrocyte membrane structure was examined using Electron Spin Resonance spectroscopy and the fluorimetric technique. The results suggest that the in vivo interaction of the drugs with the RBCs of AML patients led to a perturbation in the structure of plasma membrane components. Differences between DNR and MIT were only noted in the interaction of the drugs with deeper regions of the lipid bilayer

Circulating VEGF and its soluble receptors sVEGFR-1 and sVEGFR-2 in patients with acute leukemia.

Angiogenesis plays an important role in the pathogenesis of acute leukemia, and vascular endothelial growth factor (VEGF) is a crucial, positive regulator of this process. The biological activity of VEGF is mediated by two different receptor tyrosine kinases: VEGFR-2 and VEGFR-1. The soluble form of VEGFR-1 is likely to be a negative regulator of VEGF availability, but the physiological role of sVEGFR-2 is still unclear. The plasma levels of sVEGFR-1 and sVEGFR-2 in patients with acute leukemia have not been investigated. We measured the plasma concentrations of VEGF and its two soluble receptors in 39 AML and 15 ALL patients as well as in the control group, using the ELISA assay. We also correlated the plasma levels of these proteins with disease status and known prognostic factors. The sVEGFR-1 level was significantly higher in patients with AML and ALL than in the healthy subjects (p < 0.002 and p < 0.03 respectively). The sVEGFR-2 level was significantly higher in AML patients compared with the control group (p < 0.03). The VEGF levels in AML and ALL patients and in healthy subjects did not differ significantly. The sVEGFR-1 level was higher in AML patients with > 50% of blasts in the bone marrow (BM), WBC > 20 G/L and elevated LDH level, than in the group with BM blasts < 50% (p < 0.01), WBC < 20 G/L (p < 0.02) and a normal LDH level (p < 0.05). Positive correlations between sVEGFR-1 level and WBC (p < 0.02),% of BM blasts (p < 0.05), the absolute blast count in peripheral blood (ABC) (p < 0.009) and LDH (p < 0.000001) were found. The sVEGFR-1/VEGF ratio (R1) was calculated, and a positive correlation between R1 and ABC in AML (p < 0.03) was determined. A higher (above median) sVEGFR-1/VEGF ratio correlated with a lower CR rate and a shorter survival (p < 0.03 and p = 0.0007 respectively). In conclusion, the plasma concentration of sVEGFR-1 is higher in leukemia patients than in healthy subjects and correlates with tumour burden and poor prognosis. The sVEGFR-1/VEGF ratio may be of greater prognostic value than VEGF alone. Further investigation is recommended to better determine their function.

The search for optimal treatment in relapsed and refractory acute myeloid leukemia.

Despite the significant progress in the treatment of AML during the last 5-10 years, 20-40% of patients still do not achieve remission with standard induction therapy. In addition, 50-70% of patients in CR are likely to relapse. A major limitation of successful AML therapy is intrinsic or acquired drug resistance. Several pharmacological inhibitors of mechanisms inducing chemoresistance in leukemic cells have been investigated. New cytotoxic drugs, agents with novel mechanisms of action, and new treatment strategies are currently being investigated. The management of refractory or relapsed AML patients is reviewed in this study.