Bart J. Biemond

High-dose daunorubicin in older patients with acute myeloid leukemia

BACKGROUND A complete remission is essential for prolonging survival in patients with acute myeloid leukemia (AML). Daunorubicin is a cornerstone of the induction regimen, but the optimal dose is unknown. In older patients, it is usual to give daunorubicin at a dose of 45 to 50 mg per square meter of body-surface area. METHODS Patients in whom AML or high-risk refractory anemia had been newly diagnosed and who were 60 to 83 years of age (median, 67) were randomly assigned to receive cytarabine, at a dose of 200 mg per square meter by continuous infusion for 7 days, plus daunorubicin for 3 days, either at the conventional dose of 45 mg per square meter (411 patients) or at an escalated dose of 90 mg per square meter (402 patients); this treatment was followed by a second cycle of cytarabine at a dose of 1000 mg per square meter every 12 hours [DOSAGE ERROR CORRECTED] for 6 days. The primary end point was event-free survival. RESULTS The complete remission rates were 64% in the group that received the escalated dose of daunorubicin and 54% in the group that received the conventional dose (P=0.002); the rates of remission after the first cycle of induction treatment were 52% and 35%, respectively (P<0.001). There was no significant difference between the two groups in the incidence of hematologic toxic effects, 30-day mortality (11% and 12% in the two groups, respectively), or the incidence of moderate, severe, or life-threatening adverse events (P=0.08). Survival end points in the two groups did not differ significantly overall, but patients in the escalated-treatment group who were 60 to 65 years of age, as compared with the patients in the same age group who received the conventional dose, had higher rates of complete remission (73% vs. 51%), event-free survival (29% vs. 14%), and overall survival (38% vs. 23%). CONCLUSIONS In patients with AML who are older than 60 years of age, escalation of the dose of daunorubicin to twice the conventional dose, with the entire dose administered in the first induction cycle, effects a more rapid response and a higher response rate than does the conventional dose, without additional toxic effects. (Current Controlled Trials number, ISRCTN77039377; and Netherlands National Trial Register number, NTR212.)

Cytarabine Dose for Acute Myeloid Leukemia

BACKGROUND Cytarabine (ara-C) is an important drug in the treatment of acute myeloid leukemia (AML). High-dose cytarabine (2000 to 3000 mg per square meter of body-surface area) is toxic but results in higher rates of relapse-free survival than does the conventional dose of 100 to 400 mg per square meter. Intermediate dose levels have not been thoroughly evaluated. METHODS We compared two induction regimens in patients 18 to 60 years of age (median, 49) who had newly diagnosed AML. The intermediate-dose group, totaling 431 patients, received cytarabine at a dose of 200 mg per square meter given by continuous intravenous infusion for 24 hours during cycle 1 of induction therapy and 1000 mg per square meter by infusion for 3 hours twice daily during cycle 2 of induction therapy. The high-dose group, totaling 429 patients, received a dose-escalated regimen of 1000 mg of cytarabine per square meter every 12 hours in cycle 1 and 2000 mg per square meter twice daily in cycle 2. Patients with a complete response did not receive additional cytarabine but received consolidation therapy in a third cycle of chemotherapy (mitoxantrone-etoposide) or underwent autologous or allogeneic stem-cell transplantation. Complete remission rates, survival rates, and toxic effects were assessed for each treatment group. RESULTS At a median follow-up of 5 years, no significant differences were noted between the intermediate-dose group and the high-dose group with respect to complete remission rates (80% and 82%, respectively), probability of relapse, event-free survival at 5 years (34% and 35%), or overall survival (40% and 42%). High-dose cytarabine provided no clear advantage in any prognostic subgroup. The high-dose treatment resulted in higher incidences of grade 3 and grade 4 toxic effects (in cycle 1), prolonged hospitalization, and delayed neutrophil recovery (in cycle 2) and platelet recovery (in cycles 2 and 3). CONCLUSIONS Induction therapy with cytarabine at the lower dose already produced maximal antileukemic effects for all response end points, suggesting a plateau in the dose-response relationship above this dose level. High-dose cytarabine results in excessive toxic effects without therapeutic benefit. (Netherlands Trial Register number, NTR230.).

Intracoronary infusion of mononuclear cells from bone marrow or peripheral blood compared with standard therapy in patients after acute myocardial infarction treated by primary percutaneous coronary intervention: results of the randomized controlled HEBE trial

AIMS Previous trials that investigated cell therapy as an adjunctive therapy after acute myocardial infarction (AMI) have shown conflicting results. We designed a randomized controlled trial to determine the effect of intracoronary infusion of mononuclear cells from bone marrow (BM) or peripheral blood in patients with AMI. METHODS AND RESULTS In a multicentre trial, 200 patients with large first AMI treated with primary percutaneous coronary intervention were randomly assigned to either intracoronary infusion of mononuclear BM cells (n = 69), mononuclear peripheral blood cells (n = 66), or standard therapy (without placebo infusion) (n = 65). Mononuclear cells were delivered intracoronary between 3 and 8 days after AMI. Regional and global left ventricular myocardial function and volumes were assessed by magnetic resonance imaging before randomization and at 4 months, and clinical events were reported. The primary endpoint of the percentage of dysfunctional left ventricular segments that improved during follow-up did not differ significantly between either of the treatment groups and control: 38.6 ± 24.7% in the BM group, 36.8 ± 20.9% in the peripheral blood group, and 42.4 ± 18.7% in the control group (P = 0.33 and P = 0.14). Improvement of left ventricular ejection fraction was 3.8 ± 7.4% in the BM group, 4.2 ± 6.2% in the peripheral blood group when compared with 4.0 ± 5.8% in the control group (P = 0.94 and P = 0.90). Furthermore, the three groups did not differ significantly in changes in left ventricular volumes, mass, and infarct size and had similar rates of clinical events. CONCLUSION Intracoronary infusion of mononuclear cells from BM or peripheral blood following AMI does not improve regional or global systolic myocardial function in the HEBE trial. REGISTRATION The Netherlands Trial Register #NTR166 (www.trialregister.nl) and the International Standard Randomised Controlled Trial, #ISRCTN95796863 (http://isrctn.org).

Inhibition of plasminogen activator inhibitor-1 activity results in promotion of endogenous thrombolysis and inhibition of thrombus extension in models of experimental thrombosis.

BackgroundWe investigated the effect of inhibition of plasminogen activator inhibitor-1 (PAI-1) activity by a murine monoclonal anti-human PAI-1 antibody (MAI-12) on in vitro thrombolysis and on in vivo thrombolysis and thrombus extension in an experimental animal model for thrombosis. Methods and ResultsThrombolysis, mediated by recombinant tissue-type plasminogen activator (rt-PA), was studied in an in vitro system consisting of fibrinogen, plasminogen, and thrombin. Addition of purified platelets during clot formation inhibited rt-PA-mediated thrombolysis in a dose-dependent manner. Platelet-dependent thrombolysis resistance could be completely neutralized by the monoclonal antibody MAI-12, supporting the notion that the observed resistance is due to PAI-1 released from α-granules of platelets. Subsequently, we monitored in vivo thrombolysis and thrombus extension of human whole blood thrombi that were allowed to form in rabbit jugular veins. During thrombus formation, either MAI-12 or an irrelevant antibody was incorporated. Thrombolysis and thrombus extension were simultaneously measured during endogenous thrombolysis or upon administration of different dosages of rt-PA. We observed that endogenous thrombolysis was enhanced in the presence of MAI-12 compared with the control antibody. Significantly, thrombus extension was partially prevented by MAI-12 and not by the control antibody irrespective of whether exogenous rt-PA was systematically administered ConclusionsThese observations further confirm the essential role of PAI-1 in the regulation of the thrombolytic system and support the exploration of adjunctive therapy based on inhibition of PAI-1 activity in thrombolytic strategies.

High Prognostic Impact of Flow Cytometric Minimal Residual Disease Detection in Acute Myeloid Leukemia: Data From the HOVON/SAKK AML 42A Study

PURPOSE Half the patients with acute myeloid leukemia (AML) who achieve complete remission (CR), ultimately relapse. Residual treatment-surviving leukemia is considered responsible for the outgrowth of AML. In many retrospective studies, detection of minimal residual disease (MRD) has been shown to enable identification of these poor-outcome patients by showing its independent prognostic impact. Most studies focus on molecular markers or analyze data in retrospect. This study establishes the value of immunophenotypically assessed MRD in the context of a multicenter clinical trial in adult AML with sample collection and analysis performed in a few specialized centers. PATIENTS AND METHODS In adults (younger than age 60 years) with AML enrolled onto the Dutch-Belgian Hemato-Oncology Cooperative Group/Swiss Group for Clinical Cancer Research Acute Myeloid Leukemia 42A study, MRD was evaluated in bone marrow samples in CR (164 after induction cycle 1, 183 after cycle 2, 124 after consolidation therapy). RESULTS After all courses of therapy, low MRD values distinguished patients with relatively favorable outcome from those with high relapse rate and adverse relapse-free and overall survival. In the whole patient group and in the subgroup with intermediate-risk cytogenetics, MRD was an independent prognostic factor. Multivariate analysis after cycle 2, when decisions about consolidation treatment have to be made, confirmed that high MRD values (> 0.1% of WBC) were associated with a higher risk of relapse after adjustment for consolidation treatment time-dependent covariate risk score and early or later CR. CONCLUSION In future treatment studies, risk stratification should be based not only on risk estimation assessed at diagnosis but also on MRD as a therapy-dependent prognostic factor.

START Trial: a pilot study on STimulation of ARTeriogenesis using subcutaneous application of granulocyte-macrophage colony-stimulating factor as a new treatment for peripheral vascular disease.

Background—Granulocyte-macrophage colony-stimulating factor (GM-CSF) was recently shown to increase collateral flow index in patients with coronary artery disease. Experimental models showed beneficial effects of GM-CSF on collateral artery growth in the peripheral circulation. Thus, in the present study, we evaluated the effects of GM-CSF in patients with peripheral artery disease. Methods and Results—A double-blinded, randomized, placebo-controlled study was performed in 40 patients with moderate or severe intermittent claudication. Patients were treated with placebo or subcutaneously applied GM-CSF (10 &mgr;g/kg) for a period of 14 days (total of 7 injections). GM-CSF treatment led to a strong increase in total white blood cell count and C-reactive protein. Monocyte fraction initially increased but thereafter decreased significantly as compared with baseline. Both the placebo group and the treatment group showed a significant increase in walking distance at day 14 (placebo: 127±67 versus 184±87 meters, P=0.03, GM-CSF: 126±66 versus 189±141 meters, P=0.04) and at day 90. Change in walking time, the primary end point of the study, was not different between groups. No change in ankle-brachial index was found on GM-CSF treatment at day 14 or at day 90. Laser Doppler flowmetry measurements showed a significant decrease in microcirculatory flow reserve in the control group (P=0.03) and no change in the GM-CSF group. Conclusions—The present study does not support the use of GM-CSF for treatment of patients with moderate or severe intermittent claudication. Issues that need to be addressed are dosing, the selection of patients, and potential differences between GM-CSF effects in the coronary and the peripheral circulation.

Thrombolysis and Reocclusion in Experimental Jugular Vein and Coronary Artery Thrombosis Effects of a Plasminogen Activator Inhibitor Type 1–Neutralizing Monoclonal Antibody

BACKGROUND Thrombolytic therapy for acute myocardial infarction is often complicated by reocclusion of the initially reperfused artery. Platelets have been shown to play an important role in this process. We determined the contribution of plasminogen activator inhibitor type 1 (PAI-1), stored in the alpha-granules of platelets, to thrombolysis resistance and to reocclusion. METHODS AND RESULTS In a rabbit jugular vein thrombosis model, the effect of a PAI-1-neutralizing monoclonal antibody (CLB-2C8) on thrombolysis and thrombus growth was assessed. The effect on reperfusion, reocclusion, and duration of vessel patency was studied in a canine model of coronary artery thrombosis superimposed on a high-grade stenosis and endothelial damage. In the rabbit jugular vein model, the intravenous administration of 1 mg/kg anti-PAI-1 antibody significantly enhanced the endogenous thrombolysis from 5.5 +/- 1.3% in the animals treated with a nonspecific monoclonal antibody (control) to 13.7 +/- 2.6% in the animals treated with the anti-PAI-1 antibody. Thrombus growth was reduced significantly, from 41.3 +/- 2.6% in the control animals to 22.8 +/- 2.8% in the animals treated with the anti-PAI-1 antibody. In combination with a single bolus injection of recombinant tissue-type plasminogen activator (rTPA; 0.25 mg/kg), the anti-PAI-1 antibody reduced thrombus growth significantly, from 21.5 +/- 2.7% in the animals treated with rTPA alone to 12.2 +/- 2.6% in the animals treated with rTPA and the antibody. No additional effect of the anti-PAI-1 antibody was observed on rTPA-induced thrombolysis. In the canine coronary artery thrombosis model, the administration of a suboptimal dose of rTPA (0.45 mg/kg) induced reperfusion in 7 of the 8 dogs after 19.5 +/- 8.2 minutes. Reperfusion was followed by reocclusion in all animals after 3.3 +/- 2.6 minutes. Administration of the anti-PAI-1 antibody in combination with rTPA significantly reduced time to reperfusion (8.1 +/- 5.2 minutes) and delayed the occurrence of reocclusion to 11.6 +/- 12.5 minutes. CONCLUSIONS Administration of the anti-PAI-1 antibody (CLB-2C8) results in increased endogenous thrombolysis and inhibition of thrombus growth in a venous thrombosis model in rabbits and facilitated reperfusion and reduction of reocclusion in a canine model of coronary artery thrombosis.

Gemtuzumab ozogamicin as postremission treatment in AML at 60 years of age or more: results of a multicenter phase 3 study

In older patients with acute myeloid leukemia (AML), the prevention of relapse has remained one of the major therapeutic challenges, with more than 75% relapses after complete remission. The anti-CD33 immunotoxin conjugate gemtuzumab ozogamicin (GO) has shown antileukemic remission induction activity in patients with relapsed AML. Patients with AML or refractory anemia with excess blasts in first complete remission attained after intensive induction chemotherapy were randomized between 3 cycles of GO (6 mg/m(2) every 4 weeks) or no postremission therapy (control) to assess whether GO would improve outcome. The 2 treatment groups (113 patients receiving GO vs 119 control patients) were comparable with regard to age (60-78 years, median 67 years), performance status, and cytogenetics. A total of 110 of 113 received at least 1 cycle of GO, and 65 of 113 patients completed the 3 cycles. Premature discontinuation was mainly attributable to incomplete hematologic recovery or intercurrent relapse. Median time to recovery of platelets 50 x 10(9)/L and neutrophils 0.5 x 10(9)/L after GO was 14 days and 20 days. Nonhematologic toxicities were mild overall, but there was 1 toxic death caused by liver failure. There were no significant differences between both treatment groups with regard to relapse probabilities, nonrelapse mortality, overall survival, or disease-free survival (17% vs 16% at 5 years). Postremission treatment with GO in older AML patients does not provide benefits regarding any clinical end points. The HOVON-43 study is registered at The Netherlands Trial Registry (number NTR212) and at http://www.controlled-trials.com as ISRCTN77039377.

Oxidative stress in sickle cell disease; pathophysiology and potential implications for disease management

Sickle cell disease (SCD) is a hemoglobinopathy characterized by hemolytic anemia, increased susceptibility to infections and vaso‐occlusion leading to a reduced quality of life and life expectancy. Oxidative stress is an important feature of SCD and plays a significant role in the pathophysiology of hemolysis, vaso‐occlusion and ensuing organ damage in sickle cell patients. Reactive oxygen species (ROS) and the (end‐)products of their oxidative reactions are potential markers of disease severity and could be targets for antioxidant therapies. This review will summarize the role of ROS in SCD and their potential implication for SCD management. Am. J. Hematol. 2011.

Fibrinogen-coated albumin microcapsules reduce bleeding in severely thrombocytopenic rabbits.

Severe thrombocytopenia frequently occurs in patients receiving chemotherapy and in patients with autoimmune disorders. Thrombocytopenia is associated with bleeding, which may be serious and life threatening. Current treatment strategies for thrombocytopenia may require transfusion of allogeneic platelets, which is associated with serious drawbacks. These include the occurrence of anti-platelet antibodies, which may result in refractoriness to further platelet transfusions, and the potential risk of transfer of blood-borne diseases. Therefore, we have recently developed a platelet substitute product (Synthocytes), which is composed of human albumin microcapsules with fibrinogen immobilized on their surface. Here we show that the intravenous administration of these microcapsules not only corrects the prolonged bleeding time in rabbits rendered thrombocytopenic either by anti-platelet antibodies or by chemotherapy, but also reduces bleeding from surgical wounds inflicted in the abdominal skin and musculature. No potential systemic prothrombotic effect of the microcapsules was observed in a model of rabbit venous thrombosis. As for the mechanism of action, experiments with normal and thrombocytopenic human blood in an endothelial cell matrix-coated perfusion chamber demonstrated an interaction between the fibrinogen-coated albumin microcapsules and native platelets. It was shown that the fibrinogen-coated albumin microcapsules could facilitate platelet adhesion to endothelial cell matrix and correct the impaired formation of platelet aggregates in relatively platelet-poor blood. This study indicates that fibrinogen-coated albumin microcapsules can act to improve primary hemostasis under thrombocytopenic conditions and may eventually be a promising agent for prophylaxis and treatment of bleeding in patients with severe thrombocytopenia.