Granulocyte-macrophage colony-stimulating factor (GM-CSF) to increase efficacy of intensive sequential chemotherapy with etoposide, mitoxantrone and cytarabine (EMA) in previously treated acute myeloid leukemia: a multicenter randomized placebo-controlled trial (EMA91 Trial)

Efficacy and safety of mitoxantrone, etoposide, and cytarabine for treatment of relapsed or refractory acute myeloid leukemia

BACKGROUND/RATIONALE

Most patients with acute myeloid leukemia (AML) develop relapsed or refractory (R/R) disease after receiving initial induction chemotherapy. Salvage chemotherapy followed by allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative therapy for R/R AML. Mitoxantrone, etoposide, and cytarabine (MEC) is the current standard of care salvage regimen for R/R AML at Cleveland Clinic. The primary objective was to determine the overall remission rate (ORR: defined as patients achieving complete remission (CR) or complete remission with incomplete hematologic recovery (CRi)) in R/R AML patients who received MEC.

METHODS

Adult patients with R/R AML treated with MEC between July 1, 2014 and September 30, 2022 were included. ORR and its association with baseline characteristics were determined. Secondary outcomes included overall survival (OS), event-free survival (EFS), relapse-free survival (RFS), and safety.

RESULTS

Sixty patients were evaluated. The ORR was 51.7% (33.3% CR and 18.3% CRi). The median time from receipt of MEC to CR/CRi was 7.7 weeks. Patients with bone marrow blasts ≤20% and peripheral blood blasts ≤30% at MEC initiation were more than twice as likely to achieve CR/CRi compared to those with a higher blast burden. The median OS was 6.3 months. Twenty-four (40.0%) patients proceeded to alloHSCT. Twenty-one (35.0%) patients were transferred to the intensive care unit (ICU) during their admission.

CONCLUSIONS

MEC is an effective salvage regimen for patients with R/R AML, especially among those with low disease burden at initiation. Febrile neutropenia, infections, and severe oral mucositis were common with MEC administration.

How I treat relapsed or refractory AML

Treatment of relapsed or refractory acute myeloid leukemia (AML) has presented challenges for hematologists for decades. Despite numerous clinical studies, outcomes are consistently disappointing with 5-year overall survival rates of ∼10%. Allogeneic hematopoietic cell transplantation at the time of second complete remission remains the only reliable option with curative potential. However, recent approval of several new agents has transformed treatment paradigms that had been in place for almost half a century in AML. This new therapeutic landscape provides the opportunity to revisit the approach to relapsed or refractory AML. Through illustrative cases, we describe our approach, which increasingly relies on specific disease biology. We focus on treatment outside of the context of clinical trials because such trials are not available in most parts of the world. Primarily, we consider age, fitness to tolerate intensive chemotherapy, remission duration, and presence of a targetable mutation to guide treatment. The coming years will inevitably bring new targets and agents that may prove most effective when combined with each other and/or chemotherapy. Future studies are needed to determine how best to implement this evolving armamentarium of treatment options, to elucidate mechanisms of resistance, and to continue the pursuit of novel drug discovery.

Timed sequential salvage chemotherapy for relapsed or refractory acute myeloid leukemia

Therapy for those with relapsed or refractory acute myeloid leukemia is suboptimal. Studies have suggested that timed sequential salvage combination cytotoxic chemotherapy may have particular utility for that indication. We report here a series of ten such adult patients treated sequentially at a single center with EMA (cytarabine 500 mg/m2/day as continuous infusion on days 1-3 and days 8-10, mitoxantrone 12 mg/m2/day on days 1-3, and etoposide 200 mg/m2/day as continuous infusion on days 8-10). The overall complete remission rate was 40% (including 3 of 4 of those with relapsed disease) but use of this regimen was associated with prolonged cytopenia and a high rate of infectious adverse events. Even with the availability of modern infectious prophylaxis and therapies, the EMA regimen is likely best reserved for those with relapsed disease treated with curative intent prior to an allogeneic hematopoietic cell transplant.

Etoposide Combined with FLAG Salvage Therapy Is Effective in Multiple Relapsed/Refractory Acute Myeloid leukemia

Managing acute myeloid leukemia (AML) is often hampered by repeated failure to achieve complete remission as well as recurrent relapse that causes an emergent need for alternative salvage therapies. The efficacy of most salvage therapies is based on anthracycline combinations. In highly pretreated patients who are not eligible for anthracycline-based protocols therapeutic alternatives are limited. For this particular group we evaluated the efficacy and safety of fludarabine, cytarabine, granulocyte colony-stimulating factor (FLAG) in combination with etoposide (FLAG-Eto) in 36 patients. The complete remission rate (CR) was 25.7% with a median overall survival of 6 months (95% CI 4.5-7.7). The median disease-free survival for CR/CRi/MLFS (CR/CR with incomplete he-matological recovery/morphologic leukemia-free state) patients was 8 months (95% CI 0.6-15.5). The mortality rate on day 30 was 8% and increased on day 60 to 17%. Our results show meaningful anti-leukemic activity of the FLAG-Eto regimen with a moderate toxicity profile in heavily pretreated relapsed/refractory AML patients enabling consolidating allogeneic stem cell transplantation.

Topoisomerase II inhibitors in AML: past, present, and future

Introduction: Topoisomerase II inhibitors have long been used in the frontline and as salvage therapy for AML, with daunorubicin and idarubicin being prototypical agents in this therapeutic class, classically in combination with nucleoside analogs, e.g. cytarabine. Most recently, several other compounds from this drug class have or are being investigated. Areas covered: The current paper reviews older and newer topoisomerase II inhibitors in clinical development for the treatment of AML. The authors discuss the clinical use of these agents, current trials involving them as well as their safety profile. Important side effects of these medications including therapy-related AML (t-AML) are also covered. Expert opinion: Topoisomerase II inhibitors have helped improve outcomes in AML. Recently, the FDA approved several agents including CPX-351 for the treatment of secondary and t-AML. CPX-351 may have applicability in other high-risk myeloid diseases. Future directions include a combination of these agents with other targeted therapies. Finally, the authors believe that small molecule inhibitors, such as venetoclax and possibly immunotherapy options could also be incorporated to our treatment paradigm in selected patients.

Regulation of drug metabolizing enzymes in the leukaemic bone marrow microenvironment

The bone marrow (BM) microenvironment contributes to drug resistance in acute myeloid leukaemia (AML) and multiple myeloma (MM). We have shown that the critical drug metabolizing enzymes cytochrome P450 (CYP) 3A4 and cytidine deaminase (CDA) are highly expressed by BM stroma, and play an important role in this resistance to chemotherapy. However, what factors influence the chemoprotective capacity of the BM microenvironment, specifically related to CYP3A4 and CDA expression, are unknown. In this study, we found that the presence of AML cells decreases BM stromal expression of CYP3A4 and CDA, and this effect appears to be at least partially the result of cytokines secreted by AML cells. We also observed that stromal CYP3A4 expression is up‐regulated by drugs commonly used in AML induction therapy, cytarabine, etoposide and daunorubicin, resulting in cross‐resistance. Cytarabine also up‐regulated CDA expression. The up‐regulation of CYP3A4 associated with disease control was reversed by clarithromycin, a potent inhibitor of CYP3A4. Our data suggest that minimal residual disease states are characterized by high levels of stromal drug metabolizing enzymes and thus, strong microenvironment‐mediated drug resistance. These results further suggest a potential role for clinically targeting drug metabolizing enzymes in the microenvironment.

Initial Report of a Phase I Study of LY2510924, Idarubicin, and Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia

Background: The CXCR4/SDF-1α axis plays a vital role in the retention of stem cells within the bone marrow and downstream activation of cell survival signaling pathways. LY2510924, a second generation CXCR4, showed significant anti-leukemia activity in a murine AML model.

Methods: We conducted a phase I study to determine the safety and toxicity of LY2510924, idarubicin and cytarabine (IA) combination therapy in relapsed/refractory (R/R) AML. Eligible patients were 18–70 years of age receiving up to salvage 3 therapy. A peripheral blood absolute blast count of < 20,000/μL was required for inclusion. LY2510924 was administered daily for 7 days followed by IA from day 8. Two dose escalation levels (10 and 20 mg) were evaluated, with a plan to enroll up to 12 patients in the phase I portion.

Results: The median age of the enrolled patients (n = 11) was 55 years (range, 19–70). Median number of prior therapies was 1 (1–3). Six and five patients were treated at dose-levels “0” (10 mg) and “1” (20 mg), respectively. Only one patient experiencing a dose limiting toxicity (grade 3 rash and myelosuppression). Three and one complete responses were observed at dose-levels “0” and “1,” respectively; the overall response rate (ORR) was 36% (4 of 11 patients). A ≥ 50% decrease in CXCR4 mean fluorescence intensity was observed in 4 of 9 patients by flow cytometry, indicating incomplete suppression of CXCR4-receptor occupancy.

Conclusions: The combination of LY2510924 with IA is safe in R/R AML. Dose-escalation to a 30 mg LY2510924 dose is planned to achieve complete blockade of CXCR4 receptor occupancy, followed by expansion phase at the recommended phase 2 dose-level.

Impact on acute myeloid leukemia relapse in granulocyte colony-stimulating factor application: a meta-analysis

OBJECTIVES

This meta-analysis evaluated the impact of granulocyte colony-stimulating factor (G-CSF) added to chemotherapy on treatment outcomes including survival and disease recurrence in patients with acute myeloid leukemia (AML).

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until 19 September 2016 using search terms. Studies that investigated patients with AML who underwent stem-cell transplantation were included.

RESULTS

The overall analysis revealed a significant improvement in overall survival (OS) (P = .019) and disease-free survival (DFS) (P = .002) for patients receiving G-CSF with chemotherapy. Among patients without prior AML treatment, there was a significant improvement in DFS (P = .014) and reduction in incidence of relapse (P = .015) for those who received G-CSF. However, subgroup analyses found no significant difference between G-CSF (+) and G-CSF (-) treatments in rates of OS (P = .104) and complete remission (CR) (P = .572) for patients without prior AML treatment. Among patients with relapsed/refractory AML, there was no significant difference found between G-CSF (+) and G-CSF (-) groups for OS (P = .225), DFS (P = .209), and CR (P = .208).

DISCUSSION

Treatment with chemotherapy plus G-CSF appears to provide better survival and treatment responses compared with chemotherapy alone, particularly for patients with previously untreated AML.

ABBREVIATIONS

AML, acute myeloid leukemia; CI, confidence interval; CR, complete remission; DFS, disease-free survival; G-CSF, granulocyte colony-stimulating factor; GM-CSF, granulocyte macrophage colony-stimulating factor; HR, hazard ratio; MDS, myelodysplastic syndrome; OR, odds ratio; OS, overall survival; RCTs, randomized control trials; RR, relative risk.

Relapsed Acute Myeloid Leukemia: Need for Innovative Treatment Strategies to Improve Outcome

Relapse continues to be a major hurdle in achieving cure in patients with acute myeloid leukemia (AML). The outcome after relapse is not uniform in all patients with AML and is dependent on several prognostic variables, including age, cytogenetics at initial diagnosis, duration of first complete remission, whether an allogeneic stem cell transplant was performed during first complete remission, and the presence of a number of molecular aberrations. Despite extensive research over the past several decades, there is no standard of care for treating patients with relapsed AML. This is possibly due to the accrual of patients with widely different disease profiles in most trials for relapsed AML. With increasing insights into the disease biology based on identification of pathogenic and aberrant molecular and cellular pathways, novel therapeutic strategies are emerging. Hopefully in the near future, we can improve the outcome of patients with relapsed AML with treatment strategies based on identification of specific targets and methods to overcome these aberrant processes.

How I treat refractory and early relapsed acute myeloid leukemia

Between 10% and 40% of newly diagnosed patients with acute myeloid leukemia (AML) do not achieve complete remission with intensive induction therapy and are therefore categorized as primary refractory or resistant. Few of these patients can be cured with conventional salvage therapy. They need to be evaluated regarding eligibility for allogeneic hematopoietic stem cell transplantation (HSCT) as this is currently the treatment with the highest probability of cure. To reduce the leukemia burden prior to transplantation, salvage chemotherapy regimens need to be employed. Whenever possible, refractory/relapsed patients should be enrolled in clinical trials as we do not have highly effective and standardized treatments for this situation. Novel therapies include tyrosine kinase inhibitors, small-molecule inhibitors (eg, for Polo-like kinase 1 and aminopeptidase), inhibitors of mutated isocitrate dehydrogenase (IDH) 1 and IDH2, antibody-based therapies, and cell-based therapies. Although the majority of these therapies are still under evaluation, they are likely to enter clinical practice rapidly as a bridge to transplant and/or in older, unfit patients who are not candidates for allogeneic HSCT. In this review, we describe our approach to refractory/early relapsed AML, and we discuss treatment options for patients with regard to different clinical conditions and molecular profiles.

Vosaroxin is a novel topoisomerase-II inhibitor with efficacy in relapsed and refractory acute myeloid leukaemia

INTRODUCTION

Vosaroxin is a first-in-class anti-cancer quinolone that inhibits topoisomerase-II leading to cell cycle arrest and apoptosis. It has shown efficacy in a range of solid organ and haematopoietic tumours in vitro, and several clinical trials are underway or completed in the field of Acute Myeloid Leukaemia (AML). The treatment of relapsed and refractory AML is a clinical challenge, where long-term survival is rare without allogeneic haematopoietic stem cell transplantation.

AREAS COVERED

We review the data from the published clinical trials of vosaroxin, including the recently presented Phase III VALOR study. In combination with intermediate dose cytarabine, vosaroxin almost doubled complete response (CR) rates in relapsed and refractory AML compared with cytarabine alone, and prolonged median survival by 1.4 months.

EXPERT OPINION

Vosaroxin is a promising new agent in the treatment of AML, with the potential to improve CR rates in a high-risk group of patients with relapsed and refractory AML. However, higher CR rates have been associated with higher rates of treatment-related morbidity and mortality, especially in elderly/unfit patients. Maximising the potential of vosaroxin will therefore require the identification of patients most likely to benefit from vosaroxin-containing combination regimens.

Current Approaches in the Treatment of Relapsed and Refractory Acute Myeloid Leukemia

The limited sensitivity of the historical treatment response criteria for acute myeloid leukemia (AML) has resulted in a different paradigm for treatment compared with most other cancers presenting with widely disseminated disease. Initial cytotoxic induction chemotherapy is often able to reduce tumor burden to a level sufficient to meet the current criteria for "complete" remission. Nevertheless, most AML patients ultimately die from their disease, most commonly as clinically evident relapsed AML. Despite a variety of available salvage therapy options, prognosis in patients with relapsed or refractory AML is generally poor. In this review, we outline the commonly utilized salvage cytotoxic therapy interventions and then highlight novel investigational efforts currently in clinical trials using both pathway-targeted agents and immunotherapy based approaches. We conclude that there is no current standard of care for adult relapsed or refractory AML other than offering referral to an appropriate clinical trial.

Timed-sequential chemotherapy as induction and/or consolidation regimen for younger adults with acute myelogenous leukemia

Increasing the intensity of induction chemotherapy has generated considerable recent interest in the treatment of acute myeloid leukemia. Achieving complete remission is a sine qua non condition for prolonged disease-free survival and may affect long-term outcome. In this setting, administering a repeat course of induction shortly after completion of the first course, known as timed-sequential chemotherapy (TSC), has been tested and may lead to an improved long-term outcome. Whether these results are due to the biologic recruitment of cell cycle-specific agents is unknown. However, this strategy to intensify induction may lead to more profound myelosuppression and to potential toxicities. Here we review the results of timed-sequential chemotherapy, used as induction regimen in de novo, relapsed or refractory AML or used as post-remission therapy, and compare them with those from other types of regimens.

Homoharringtonine in combination with cytarabine and aclarubicin in the treatment of refractory/relapsed acute myeloid leukemia: a single-center experience

To assess the efficacy and toxicity of HAA regimen (Homoharringtonine 4 mg/m(2)/day, days 1-3; cytarabine 150 mg/m(2)/day, days 1-7; aclarubicin 12 mg/m(2)/day, days 1-7) as a salvage therapy in the treatment of refractory and/or relapsed acute myeloid leukemia (AML), 46 patients with refractory and/or relapsed AML, median age 37 (16-65) years, participated in this clinical study. The median follow-up was 41 (10-86) months. Eighty percent of patients achieved complete remission (CR), and the first single course of re-induction HAA regimen resulted in CR rate of 76.1 %. The study protocol allowed two courses of induction. The CR rates of patients with favorable, intermediate and unfavorable cytogenetics were 90 %, 88.9 %, and 37.5 %, respectively. For all patients, the estimated 3-year overall survival (OS) rate was 42 %, and the estimated relapse free survival (RFS) at 3 years for the 36 CR cases was 49 %. The toxicities associated with HAA regimen were acceptable. HAA is a good choice in cases with refractory/relapsing AML for salvage chemotherapy, preferably with a high-efficacy and low-toxicity profile.

Salvage therapy for relapsed or refractory acute myeloid leukemia

There are a significant number of patients diagnosed with acute leukemia who either fail to achieve remission or who relapse thereafter. Challenges in treating this patient population include accurately assessing prognosis of disease and whether remission can be achieved; assessing the ability of patients to tolerate aggressive salvage therapies; choosing a salvage therapy that is most likely to succeed; and identifying suitable patients for hematopoietic stem cell transplantation. Despite the development of a variety of new investigational therapies, relapsed or refractory acute myeloid Leukemia remains a difficult clinical problem. Clinicians will need to consider all currently available approaches, including cytotoxic chemotherapy, targeted agents, and allogeneic stem cell transplantation, to optimize outcomes.

Colony-stimulating factors for prevention and treatment of infectious complications in patients with acute myelogenous leukemia

BACKGROUND

Acute myelogenous leukemia (AML) is a fatal bone marrow cancer. Colony-stimulating factors (CSFs) are frequently administered during and after chemotherapy to reduce complications. However, their safety with regard to disease-related outcomes and survival in AML is unclear. Therefore, we performed a systematic review and meta-analysis to evaluate the impact of CSFs on patient outcomes, including survival.

OBJECTIVES

To assess the safety/efficacy of CSFs with regard to disease-related outcomes and survival in patients with AML.

SEARCH METHODS

We conducted a comprehensive search strategy. We identified relevant randomized clinical trials by searching the Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 7), MEDLINE (January 1966 to July 2010), LILACS (up to December 2009), databases of ongoing trials and relevant conference proceedings.

SELECTION CRITERIA

Randomized controlled trials that compared the addition of CSFs during and following chemotherapy to chemotherapy alone in patients with AML. We excluded trials evaluating the role of CSFs administered for the purpose of stem cell collection and/or priming (e.g. before and/or only for the duration of chemotherapy).

DATA COLLECTION AND ANALYSIS

Two review authors appraised the quality of trials and extracted data. For each trial, we expressed results as relative risk (RR) with 95% confidence intervals (CI) for dichotomous data. We analyzed time-to-event outcomes as hazard ratios (HRs).

MAIN RESULTS

The search yielded 19 trials including 5256 patients. The addition of CSFs to chemotherapy yielded no difference in all-cause mortality at 30 days and at the end of follow up (RR 0.97; 95% CI 0.80 to 1.18 and RR 1.01; 95% CI 0.98 to 1.05, respectively) or in overall survival (HR 1.00; 95% 0.93 to 1.08). There was no difference in complete remission rates (RR 1.03; 95% CI 0.99 to 1.07), relapse rates (RR 0.97; 95% CI 0.89 to 1.05) and disease-free survival (HR 1.00; 95% CI 0.90 to 1.13). CSFs did not decrease the occurrence of bacteremias (RR 0.96; 95% CI 0.82 to 1.12), nor the occurrence of invasive fungal infections (RR 1.40; 95% CI 0.90 to 2.19). CSFs marginally increased adverse events requiring discontinuation of CSFs as compared to the control arm (RR 1.33; 95% CI 1.00 to 1.56).

AUTHORS' CONCLUSIONS

In summary, colony-stimulating factors should not be given routinely to acute myelogenous leukemia patients post-chemotherapy since they do not affect overall survival or infectious parameters including the rate of bacteremias and invasive fungal infections.

Favorable effect of priming with granulocyte colony-stimulating factor in remission induction of acute myeloid leukemia restricted to dose escalation of cytarabine

The clinical value of chemotherapy sensitization of acute myeloid leukemia (AML) with G-CSF priming has remained controversial. Cytarabine is a key constituent of remission induction chemotherapy. The effect of G-CSF priming has not been investigated in relationship with variable dose levels of cytarabine. We randomized 917 AML patients to receive G-CSF (456 patients) or no G-CSF (461 patients) at the days of chemotherapy. In the initial part of the study, 406 patients were also randomized between 2 cytarabine regimens comparing conventional-dose (199 patients) versus escalated-dose (207 patients) cytarabine in cycles 1 and 2. We found that patients after induction chemotherapy plus G-CSF had similar overall survival (43% vs 40%, P = .88), event-free survival (37% vs 31%, P = .29), and relapse rates (34% vs 36%, P = .77) at 5 years as those not receiving G-CSF. However, patients treated with the escalated-dose cytarabine regimen benefited from G-CSF priming, with improved event-free survival (P = .01) and overall survival (P = .003), compared with patients without G-CSF undergoing escalated-dose cytarabine treatment. A significant survival advantage of sensitizing AML for chemotherapy with G-CSF was not apparent in the entire study group, but it was seen in patients treated with escalated-dose cytarabine during remission induction. The HOVON-42 study is registered under The Netherlands Trial Registry (www.trialregister.nl) as #NTR230.

Clofarabine plus cytarabine compared with cytarabine alone in older patients with relapsed or refractory acute myelogenous leukemia: results from the CLASSIC I Trial

PURPOSE

To compare the receipt of clofarabine plus cytarabine (Clo+Ara-C arm) with cytarabine (Ara-C arm) in patients ≥ 55 years old with refractory or relapsed acute myelogenous leukemia (AML).

PATIENTS AND METHODS

Patients were randomly assigned to receive either clofarabine (Clo) 40 mg/m(2) or a placebo followed by Ara-C 1 g/m(2) for five consecutive days. The primary end point was overall survival (OS). Secondary end points included event-free survival (EFS), 4-month EFS, overall remission rate (ORR; complete remission [CR] plus CR with incomplete peripheral blood count recovery), disease-free survival (DFS), duration of remission (DOR), and safety.

RESULTS

Among 320 patients with confirmed AML (median age, 67 years), the median OS was 6.6 months in the Clo+Ara-C arm and 6.3 months in the Ara-C arm (hazard ratio [HR], 1.00; 95% CI, 0.78 to 1.28; P = 1.00). The ORR was 46.9% in the Clo+Ara-C arm (35.2% CR) versus 22.9% in the Ara-C arm (17.8% CR; P < .01). EFS (HR: 0.63; 95% CI, 0.49 to 0.80; P < .01) and 4-month EFS (37.7% v 16.6%; P < .01) favored the Clo+Ara-C arm compared with Ara-C arm, respectively. DFS and DOR were similar in both arms. Overall 30-day mortality was 16% and 5% for CLO+Ara-C and Ara-C arms, respectively. In the Clo+Ara-C and Ara-C arms, the most common grade 3 to 4 toxicities were febrile neutropenia (47% v 35%, respectively), hypokalemia (18% v 11%, respectively), thrombocytopenia (16% v 17%, respectively), pneumonia (14% v 10%, respectively), anemia (13% v 0%, respectively), neutropenia (11% v 9%, respectively), increased AST (11% v 2%, respectively), and increased ALT (10% v 3%, respectively).

CONCLUSION

Although the primary end point of OS did not differ between arms, Clo+Ara-C significantly improved response rates and EFS. Study follow-up continues, and the role of clofarabine in the treatment of adult patients with AML continues to be investigated.

Colony-stimulating factors for prevention and treatment of infectious complications in patients with acute myelogenous leukemia

BACKGROUND

Acute myelogenous leukemia (AML) is a fatal bone marrow cancer. Colony-stimulating factors (CSFs) are frequently administered during and after chemotherapy to reduce complications. However, their safety with regard to disease-related outcomes and survival in AML is unclear. Therefore, we performed a systematic review and meta-analysis to evaluate the impact of CSFs on patient outcomes, including survival.

OBJECTIVES

To assess the safety/efficacy of CSFs with regard to disease-related outcomes and survival in patients with AML.

SEARCH STRATEGY

We conducted a comprehensive search strategy. We identified relevant randomized clinical trials by searching the Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 7), MEDLINE (January 1966 to July 2010), LILACS (up to December 2009), databases of ongoing trials and relevant conference proceedings.

SELECTION CRITERIA

Randomized controlled trials that compared the addition of CSFs during and following chemotherapy to chemotherapy alone in patients with AML. We excluded trials evaluating the role of CSFs administered for the purpose of stem cell collection and/or priming (e.g. before and/or only for the duration of chemotherapy).

DATA COLLECTION AND ANALYSIS

Two review authors appraised the quality of trials and extracted data. For each trial, we expressed results as relative risk (RR) with 95% confidence intervals (CI) for dichotomous data. We analyzed time-to-event outcomes as hazard ratios (HRs).

MAIN RESULTS

The search yielded 19 trials including 5256 patients. The addition of CSFs to chemotherapy yielded no difference in all-cause mortality at 30 days and at the end of follow up (RR 0.97; 95% CI 0.80 to 1.18 and RR 1.01; 95% CI 0.98 to 1.05, respectively) or in overall survival(HR 1.00; 95% 0.93 to 1.08). There was no difference in complete remission rates(RR 1.03; 95% CI 0.99 to 1.07), relapse rates(RR 0.97; 95% CI 0.89 to 1.05) and disease-free survival(HR 1.00; 95% CI 0.90 to 1.13). CSFs did not decrease the occurrence of bacteremias(RR 0.96; 95% CI 0.82 to 1.12), nor the occurrence of invasive fungal infections(RR 1.40; 95% CI 0.90 to 2.19). CSFs marginally increased adverse events requiring discontinuation of CSFs as compared to the control arm(RR 1.33; 95% CI 1.00 to 1.56).

AUTHORS' CONCLUSIONS

The addition of CSFs to chemotherapy does not adversely influence all-cause mortality, complete remission or relapse rates in patients with AML. Although the benefit of CSFs is limited to reduction of neutropenic and febrile days, they can be administered safely when necessary.

Peripheral blasts on day 21 of induction chemotherapy in a patient with core binding factor acute myeloid leukemia: more than meets the eye

The combination of fludarabine, high-dose cytarabine, gemtuzumab ozogamicin, and granulocyte colony-stimulating factor (G-CSF), the FLAG-GO protocol, has resulted in excellent response rates and superior relapse-free survival as first-line therapy for patients with core binding factor acute myeloid leukemia (AML). A side effect of administration of G-CSF is an increase in peripheral white blood cell count and blast cell percentage during the recovery phase of the bone marrow after induction chemotherapy. A 60-year-old man with inversion 16 AML was admitted for induction chemotherapy with the FLAG-GO protocol at our institution. On day 21 of his induction regimen, he was noted to have blasts in both the peripheral smear and in the bone marrow that resolved on their own without any intervention by day 28. Our case report underscores the importance of recognizing this phenomenon associated with the administration of G-CSF, and waiting for 5-7 days before administering re-induction therapy or classifying the disease as primary refractory AML.

Which AML subsets benefit from leukemic cell priming during chemotherapy? Long-term analysis of the ALFA-9802 GM-CSF study

BACKGROUND

: Priming with granulocytic hematopoietic growth factors may modulate cell cycle kinetics of leukemic cells and render them more susceptible to phase-specific chemotherapeutic agents. In a first report, we have shown that priming with granulocyte-macrophage colony-stimulating factor (GM-CSF) may enhance complete remission (CR) rate and event-free survival (EFS) in younger adults with acute myeloid leukemia (AML).

METHODS

: In this randomized trial, 259 patients with AML were randomized at baseline to receive or not receive GM-CSF concurrently with all cycles of chemotherapy. The effects of GM-CSF on survival were reported herein with a long-term follow-up and studied according to distinct biological subgroups defined on cytogenetics and molecular markers.

RESULTS

: The EFS rate was better in the GM-CSF group (43% vs 34%; P = .04). GM-CSF did not improve the outcome in patients from good risk subgroups, while patients from poor risk subgroups benefited from GM-CSF therapy. In this population, the difference in terms of EFS probability was mainly observed in patients with high initial white blood cell count and in those with FLT3-ITD or MLL rearrangement. When combining these 2 molecular abnormalities for comparison of the effect of GM-CSF priming, the difference in terms of EFS was highly significant (5-year EFS, 39% with GM-CSF vs 8% without GM-CSF; P = .007).

CONCLUSIONS

: Sensitization of leukemic cells and their progenitors by GM-CSF appears as a plausible strategy for improving the outcome of patients with newly diagnosed AML. Patients with poor-prognosis FLT3-ITD or MLL rearrangement might be a good target population to further investigate priming strategies. Cancer 2010. (c) 2010 American Cancer Society.

Current and emerging therapies for acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a clonal disease characterized by the proliferation and accumulation of myeloid progenitor cells in the bone marrow, which ultimately leads to hematopoietic failure. The incidence of AML increases with age, and older patients typically have worse treatment outcomes than do younger patients.

OBJECTIVE

This review is focused on current and emerging treatment strategies for nonpromyelocytic AML in patients aged <60 years.

METHODS

A literature review was conducted of the PubMed database for articles published in English. Publications from 1990 through March 2009 were scrutinized, and the search was updated on August 26, 2009. The search terms used were: acute myeloid leukemia in conjunction with treatment, chemotherapy, stem cell transplantation, and immunotherapy. Clinical trials including adults with AML aged > or =19 years were selected for analysis. Conference proceedings from the previous 5 years of The American Society of Hematology, The European Hematology Association, and The American Society for Blood and Marrow Transplantation were searched manually. Additional relevant publications were obtained by reviewing the references from the chosen articles.

RESULTS

Cytarabine (AraC) is the cornerstone of induction therapy and consolidation therapy for AML. A standard form of induction therapy consists of AraC (100-200 mg/m(2)), administered by a continuous infusion for 7 days, combined with an anthracycline, administered intravenously for 3 days. Consolidation therapy comprises treatment with additional courses of intensive chemotherapy after the patient has achieved a complete remission (CR), usually with higher doses of the same drugs as were used during the induction period. High-dose AraC (2-3 g/m(2)) is now a standard consolidation therapy for patients aged <60 years. Despite substantial progress in the treatment of newly diagnosed AML, 20% to 40% of patients do not achieve remission with the standard induction chemotherapy, and 50% to 70% of first CR patients are expected to relapse within 3 years. The optimum strategy at the time of relapse, or for patients with the resistant disease, remains uncertain. Allogeneic stem cell transplantation has been established as the most effective form of antileukemic therapy in patients with AML in first or subsequent remission. New drugs are being evaluated in clinical studies, including immunotoxins, monoclonal antibodies, nucleoside analogues, hypomethylating agents, farnesyltransferase inhibitors, alkylating agents, FMS-like tyrosine kinase 3 inhibitors, and multidrug-resistant modulators. However, determining the success of these treatment strategies ultimately requires well-designed clinical trials, based on stratification of the patient risk, knowledge of the individual disease, and the drug's performance status.

CONCLUSIONS

Combinations of AraC and anthracyclines are still the mainstay of induction therapy, and use of high-dose AraC is now a standard consolidation therapy in AML patients aged <60 years. Although several new agents have shown promise in treating AML, it is unlikely that these agents will be curative when administered as monotherapy; it is more likely that they will be used in combination with other new agents or with conventional therapy.

Continuous infusion of intermediate-dose cytarabine and fludarabine with idarubicin for patients younger than 60 years with resistant acute myeloid leukemia: a prospective, multicenter phase II study

We assessed continuous infusion (CI) of fludarabine and cytarabine (FLAG) plus idarubicin for patients under 60-years old with resistant acute myeloid leukemia (AML). Induction chemotherapy consisted of idarubicin (12 mg/m(2) iv infusion over 30 min on Days 1-3), plus fludarabine (30 mg/m2/day) and cytarabine (1,000 mg/m(2)/day) on Days 1-5 as a 24-hr CI. G-CSF was added on Days 1-5. The 29 patients enrolled were of median age 40 years (range, 18-57 years); of these, 8 (27.6%) had primary refractory disease, 19 (65.5%) were in early relapse, and 1 each (3.4%) was in multiple relapse and relapse after SCT. In response to induction, 8 patients (27.6%) achieved CR, 2 (6.9%) achieved CRp, and 19 (65.5%) failed treatment; of the latter, 14 had aplasia, three had an indeterminate course, and two showed resistance. Seven patients remain alive, while two were lost to follow-up. Nineteen patients died, 14 of infection, one of toxicity during consolidation, three of relapse after SCT, and two of persistent disease. These findings indicate that although CI of FLAG plus idarubicin was effective for eradicating blasts, it carried a high risk of toxicity. Reduced doses are recommended for CI of FLAG plus idarubicin.

The role of timed sequential chemotherapy in adult acute myelogenous leukemia

Consecutive trials of timed sequential chemotherapy (TSC) have been conducted in adults with acute myelogenous leukemia. The rationale for TSC was based on the observation that leukemic cells can be recruited synchronously into the cell cycle after initial intensive therapy, at which time they may become more susceptible to killing by chemotherapeutic agents. Achieving complete remission is essential for prolonged disease-free survival and may affect long-term outcome. TSC has led to higher rates of complete remission and has improved long-term outcomes. This article reviews the results of important trials in which TSC was used as an induction regimen in de novo, relapsed, or refractory acute myelogenous leukemia or as postremission therapy.

Current status of growth factors in the treatment of acute myeloid and lymphoblastic leukemia

The safety of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with acute leukemia has been well established in numerous clinical trials. The primary aim of these studies was to determine whether CSFs, when used as adjuncts to intensive chemotherapy, reduced the duration of neutropenia, prevented febrile neutropenia, infections, and hospitalization rates, and improved response and overall outcome in patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). Despite considerable efforts in divers clinical settings, the potential advantages of hematopoietic growth factors in the management of these leukemias remain inconclusive. In general, individual published trials have shown declines in the incidence and/or duration of neutropenia but have not consistently demonstrated a reduction in the overall frequency of infectious complications or the duration of hospitalization. Most protocols also have failed to show a benefit in terms of disease-free or overall survival. Nevertheless, improvements in "soft" clinical end points, such as incidence of severe infections, may be clinically important and contribute, even if only incrementally, to the patient's quality of life. Selection of those patients likely to benefit from growth factors in a specific clinical setting is a worthwhile endeavour.

Effect of priming with granulocyte-macrophage colony-stimulating factor in younger adults with newly diagnosed acute myeloid leukemia: a trial by the Acute Leukemia French Association (ALFA) Group

In a multicenter trial, 259 young adults (15-49 years) with newly diagnosed acute myeloid leukemia (AML) were first randomized to receive a timed-sequential induction regimen given either alone (135 patients) or concomitantly with granulocyte-macrophage colony-stimulating factor (GM-CSF) (124 patients). Patients reaching complete remission (CR) were then randomized to compare a timed-sequential consolidation to a postremission chemotherapy including four cycles of high-dose cytarabine followed by maintenance courses. In the appropriate arm, GM-CSF was given concurrently with chemotherapy during all cycles of consolidation. CR rates were significantly better in the GM-CSF arm (88 vs 78%, P<0.04), but did not differ after salvage. Patients receiving GM-CSF had a higher 3-year event-free survival (EFS) estimate (42 vs 34%), but GM-CSF did not impact on overall survival. Patients with intermediate-risk cytogenetics benefited more from GM-CSF therapy (P=0.05) in terms of EFS than patients with other cytogenetics. This was also confirmed when considering only patients following the second randomization, or subgroups defined by a prognostic index based on cytogenetics and the number of courses required for achieving CR. Priming of leukemic cells with hematopoietic growth factors is a means of enhancing the efficacy of chemotherapy in younger adults with AML.

Pilot remission induction therapy with idarubicin, plus an intensified dose of ara-C and priming with granulocyte colony-stimulating factor for acute myeloid leukemia

BACKGROUND

The sensitization of leukemic cells with hematopoietic growth factors can enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML). Intensified remission induction (RI) therapy can also improve the treatment results for AML. Therefore, the current trial attempted to evaluate the efficacy and toxicity of granulocyte colony-stimulating factor (G-CSF) priming and a dose intensification of Ara-C in RI chemotherapy for AML.

METHODS

A total of 29 patients with newly diagnosed AML received G-CSF-priming RI chemotherapy consisting of idarubicin (12 mg/m2, days 1-3), G-CSF (150 microg/m2, days 3-8) and Ara-C (500 mg/m2, b.i.d., days 4-8), and the outcomes were compared with those of a historical group treated with a standard regimen consisting of idarubicin (12 mg/m2, days 1-3) and Ara-C (100 mg/m2, days 1-7).

RESULTS

There was no difference in sex, age, subtype and cytogenetic risk between the two groups. The complete remission rate and treatment-related mortality were 72 and 17% for the G-CSF-primed group (p = 0.89) and 71 and 10% for the historical group (p = 0.32), respectively. The time to neutrophil recovery (25 vs. 24 days, p = 0.17) and platelet recovery (24 vs. 23 days, p = 0.23) did not differ significantly between the two groups. Similarly, the duration of fever was not significantly different (5 vs. 7 days, p = 0.58). Thirteen patients (45%) experienced fever and 5 patients (17%) manifested skin rashes during the G-CSF priming. After a median follow-up of 336 days, the 1-year overall survival, disease-free survival and event-free survival rates were 72 vs. 63% (p = 0.83), 74 vs. 56% (p = 0.059) and 53 vs. 38% (p = 0.32), respectively.

CONCLUSION

The sensitization of leukemic cells with growth factors and dose intensification seem to be clinically applicable means to enhance the efficacy of RI chemotherapy only in selected patients with AML, thereby warranting further studies focusing on specific subgroups of AML patients.

Role of cytokines in the treatment of acute leukemias: a review

Myeloid growth factors, such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, have been used to decrease the duration of chemotherapy-induced neutropenia and thereby reduce the incidence and severity of infections in various regimens used to treat acute myeloid leukemia and acute lymphoblastic leukemia. These growth factors have also been used to recruit dormant myeloid leukemia cells into the S phase of cell cycle in order to increase their susceptibility to the antileukemic effects of agents such as cytarabine. Multiple prospective randomized trials have examined the benefit and safety of the addition of growth factors before, during, and after chemotherapy. A reduction in the duration of neutropenia has been the most consistent finding; this has not been associated with stimulation of leukemia cells, the main concern of using this strategy. Unfortunately, few studies have reported a benefit in prolonging the duration of disease-free survival or overall survival. Other cytokines, including interleukins and thrombopoietin, have also been evaluated for their theoretical ability to recruit immune mechanisms to eradicate residual leukemia burden after chemotherapy, and to stimulate platelet production. In this review, we summarize the clinical experience with these growth factors in treating acute leukemias.

Continuous infusion intermediate-dose cytarabine, mitoxantrone, plus etoposide for refractory or early relapsed acute myelogenous leukemia

For refractory and early relapsed AML, this prospective phase II clinical trial evaluated a salvage chemotherapy regimen, which was consisted of continuous infusion intermediate-dose cytarabine (1g/m(2)/day, 24h i.v. infusion x 5), mitoxantrone (12 mg/m(2)/day x 3), and etoposide (150 mg/m(2)/day x 3). We treated 33 patients and 17 (51.5%) achieved CR with a median duration of 117 days. Median overall survival was 219 days. Our results suggest that continuous infusion intermediate-dose cytarabine, together with mitoxantrone and etoposide, may induce CR in a significant proportion of patients with refractory or early relapsed AML, although remission duration was short.

Final report of the efficacy and safety of gemtuzumab ozogamicin (Mylotarg) in patients with CD33-positive acute myeloid leukemia in first recurrence

BACKGROUND

In this study, the authors analyzed the efficacy and safety of gemtuzumab ozogamicin (GO) (Mylotarg), an antibody-targeted chemotherapy for CD33-positive acute myeloid leukemia (AML).

METHODS

Patients with CD33-positive AML in first recurrence were entered in 3 open-label, single-arm, Phase II studies. Patients received monotherapy with GO 9 mg/m(2) as a 2-hour intravenous infusion in 2 doses separated by 2 weeks. Patients were evaluated for remission, survival, and treatment-emergent adverse events.

RESULTS

Two hundred seventy-seven patients (median age, 61 yrs) were treated with GO, and 71 patients (26%) achieved remission, which was defined as < or = 5% blasts in the bone marrow without leukemic blasts in the peripheral blood, neutrophil recovery to > or = 1500/microL, hemoglobin > or = 9 g/dL, and independence from red blood cell and platelet transfusions. Complete remission (CR) with platelet recovery (> or = 100,000/microL) or without full platelet recovery (< 100,000/microL) (CRp) was observed in 35 patients (13%) and 36 patients (13%), respectively. The median recurrence-free survival was 6.4 months for patients who achieved CR and 4.5 months for patients who achieved CRp. Although expected incidences of Grade 3 or 4 neutropenia (98%) and thrombocytopenia (99%) were observed, the incidence of Grade 3 or 4 sepsis (17%) and pneumonia (8%) was relatively low. Grade 3 or 4 hyperbilirubinemia and hepatic aspartate aminotransferase and alanine aminotransferase elevations were reported in 29%, 18%, and 9% of patients, respectively; 0.9% of patients who did not undergo prior or subsequent hematopoietic stem cell transplantation developed hepatic venoocclusive disease after GO treatment.

CONCLUSIONS

When it was administered to patients with CD33-positive AML in first recurrence, single-agent GO induced a 26% remission rate with a generally acceptable safety profile.

Colony-stimulating factors in the management of neutropenia and its complications

Granulocyte colony-stimulating factor (CSF) and granulocyte-macrophage CSF are potent drugs used to increase neutrophil counts after myelosuppressive chemotherapy. However, in various indications, the use of CSFs has no clinical benefit with regard to morbidity or mortality from infectious complications, frequency of antibiotic use, or rate of hospitalization. Thus, the application of CSFs should be limited to indications with proven clinical benefits or evidence of cost-effectiveness. This review will provide an overview of the state-of-the-art use of CSFs in chemotherapy-associated neutropenia, transplantation, and bone marrow failure syndromes. In addition, recently developed drugs for accelerated hematopoietic recovery will be presented.

Use of glycosylated recombinant human G-CSF (lenograstim) during and/or after induction chemotherapy in patients 61 years of age and older with acute myeloid leukemia: final results of AML-13, a randomized phase-3 study

The role of glycosylated recombinant human granulocyte colony-stimulating factor (G-CSF) in the induction treatment of older adults with acute myeloid leukemia (AML) is still uncertain. In this trial, a total of 722 patients with newly diagnosed AML, median age 68 years, were randomized into 4 treatment arms: (A) no G-CSF; (B) G-CSF during chemotherapy; (C) G-CSF after chemotherapy until day 28 or recovery of polymorphonuclear leukocytes; and (D) G-CSF during and after chemotherapy. The complete remission (CR) rate was 48.9% in group A, 52.2% in group B, 48.3% in group C, and 64.4% in group D. Analysis according to the 2 x 2 factorial design indicated that the CR rate was significantly higher in patients who received G-CSF during chemotherapy (58.3% for groups B + D vs 48.6% for groups A + C; P = .009), whereas no significant difference was observed between groups A + B and C + D (50.6% vs 56.4%, P = .12). In terms of overall survival, no significant differences were observed between the various groups. Patients who received G-CSF after chemotherapy had a shorter time to neutrophil recovery (median, 20 vs 25 days; P < .001) and a shorter hospitalization (mean, 27.2 vs 29.7 days; P < .001). We conclude that although priming with G-CSF can improve the CR rate, the use of G-CSF during and/or after chemotherapy has no effect on the long-term outcome of AML in older patients.

Functional analysis of apoptosis induction in acute myeloid leukaemia-relevance of karyotype and clinical treatment response

Deficiencies or structural defects of the apoptotic machinery have been postulated as a potential mechanism for a broad resistance of acute myeloid leukaemia (AML) blasts towards cytotoxic therapy comprising chemotherapeutic agents with diverse pharmacodynamic principles but also cell-mediated cytotoxicity of the graft-versus-leukaemia effect, for example, in the setting of allogeneic transplantation. This hypothesis was systematically tested by functionally analysing the early, intermediate and late events of the apoptotic process in primary AML (n = 31) blasts following activation of the intrinsic and extrinsic pathway of apoptosis (etoposide and cytarabine as DNA damaging agents, FAS-ligand as an activator of the death receptor pathway). Activation of the extrinsic pathway by FAS-ligand did not induce apoptosis in primary AML, instead the proapoptotic signal was shown to 'fade', even in the early phase of the apoptotic sequence. However, activation of the intrinsic pathway induced severe cytotoxicity in all samples that showed the characteristic features of typical apoptosis, with a prominent apoptotic volume decrease (blebbing) in the early phase, significant increases in caspase 3 activity (intermediate or effector phase) and breakdown of cellular energy production in the late phase of apoptosis. These characteristics did not differ between prognostically favourable versus unfavourable AML karyotypes or between clinically responding versus refractory AML--indicating that a functional apoptotic apparatus is present even in the unfavourable AML subgroups. Our data indicate that the mechanism for a broad clinical resistance is not a dysfunctional apparatus per se but rather the consequence of anti-apoptotic regulation impeding otherwise functional apoptotic machinery.

A phase 3 study of three induction regimens and of priming with GM-CSF in older adults with acute myeloid leukemia: a trial by the Eastern Cooperative Oncology Group

The optimal induction for older adults with acute myeloid leukemia (AML) is unknown. Several anthracyclines have been proposed, but the data remain equivocal. Additionally, few prospective trials of priming with hematopoietic growth factors to cycle leukemia cells prior to induction chemotherapy have been conducted. Three hundred and sixty-two older adults with previously untreated AML were randomized to either daunorubicin, idarubicin or mitoxantrone with a standard dose of cytarabine as induction therapy. In addition, 245 patients were also randomized to receive granulocyte-macrophage colony-stimulating factor (GM-CSF) or placebo beginning 2 days prior to induction chemotherapy and continuing until marrow aplasia. No difference was observed in the disease-free overall survival or in toxicity among patients receiving any of the 3 induction regimens or among those receiving growth factor or placebo for priming. However, the complete remission rate for the first 113 analyzable patients, who did not participate in the priming study and started induction therapy 3 to 5 days earlier than those who did, was significantly higher (50% versus 38%; P = .03). None of the anthracyclines is associated with improved outcome in older adults. Priming with hematopoietic growth factor did not improve response when compared with placebo. Furthermore, delaying induction therapy in older adults may lead to a lower complete remission rate.

No benefit from adding GM-CSF to induction chemotherapy in transforming myelodysplastic syndromes: better outcome in patients with less proliferative disease

In this prospective randomized multicenter trial 93 patients, median age 72 years, with RAEB-t (n=25) and myelodysplastic syndrome (MDS)-AML (n=68) were allocated to a standard induction chemotherapy regimen (TAD 2+7) with or without addition of granulocyte-macrophage-CSF (GM-CSF). The overall complete remission (CR) rate was 43% with no difference between the arms. Median survival times for all patients, CR patients, and non-CR patients were 280, 550, and 100 days, respectively, with no difference between the arms. Response rates were significantly better in patients with serum lactate dehydrogenase (S-LDH) levels </=9.5 microkat/l, bone marrow cellularity </=70%, and WBC counts <4.0 x 10(9)/l, but S-LDH was the only variable independently associated with response by logistic regression analysis. Cox's regression analysis identified four significant prognostic factors for survival: bone marrow cellularity, S-LDH, cytogenetic risk group (International Prognostic Scoring System), and age. Only bone marrow cellularity (P=0.01) and S-LDH (P=0.0003) retained statistical significance in the log-rank test. Severe adverse events were significantly more common in the GM-TAD arm (P=0.01). Thus, addition of GM-CSF to chemotherapy showed no clinical benefit in terms of response but carried an increased risk for side effects. We present a clinically useful tool to predict response to chemotherapy and survival in elderly patients with transforming MDS, favoring patients with features of less proliferative disease.

Timed-sequential chemotherapy with concomitant granulocyte colony-stimulating factor for newly diagnosed de novo acute myelogenous leukemia

EMA, consisting of etoposide, mitoxantrone, and cytarabine, is a timed-sequential chemotherapy (TSC) regimen and an efficacious option for induction treatment of acute myelogenous leukemia (AML). Hematopoietic growth factors (HGFs) have been shown to recruit leukemic blasts into cell cycle. We postulated the addition of granulocyte colony-stimulating factor (G-CSF) to EMA (EMA-G) might enhance treatment efficacy. EMA-G consisted of mitoxantrone on days 1-3, cytarabine on days 1-3 and 8-10, etoposide on days 8-10, and G-CSF from day 4 until absolute neutrophil count (ANC) >500/microl. In total, 28 patients were enrolled. All patients had newly diagnosed de novo AML. The median age was 42 years. Of the 27 patients with cytogenetic analysis, six had favorable karyotype, 18 intermediate karyotype, and three unfavorable karyotype. The median follow-up was 37.5 months. The median time for both ANC recovery and last platelet transfusion was 26 days. The toxicities associated with this regimen were no more than those expected with the standard chemotherapy. In all, 24 (86%) patients achieved complete remission (CR), three (11%) patients had no response, and one patient died within 24 h of induction therapy before response could be evaluated. Of the 24 patients who achieved CR, 22 received high-dose cytosine arabinoside and two received allogeneic bone marrow transplant as initial postremission therapy. For the whole cohort, the estimated 3-year survival rate was 67%. The median relapse-free survival was 30.5 months. We conclude that EMA-G regimen is a safe regimen and administration of G-CSF during and after induction treatment is not associated with prolongation of marrow aplasia or acceleration of leukemia relapse. It is efficacious for induction therapy for newly diagnosed de novo AML. A high CR rate can be achieved with only one course of this chemotherapy.

Granulocyte colony-stimulating factor and the risk of secondary myeloid malignancy after etoposide treatment

Event-free survival for children with acute lymphoblastic leukemia (ALL) now exceeds 80% in the most effective trials. Failures are due to relapse, toxicity, and second cancers such as therapy-related myeloid leukemia or myelodysplasia (t-ML). Topoisomerase II inhibitors and alkylators can induce t-ML; additional risk factors for t-ML remain poorly defined. The occurrence of t-ML among children who had received granulocyte colony-stimulating factor (G-CSF) following ALL remission induction therapy prompted us to examine this and other putative risk factors for t-ML in 412 children treated on 2 consecutive ALL protocols from 1991 to 1998. All children received etoposide and anthracyclines, 99 of whom received G-CSF; 284 also received cyclophosphamide, 58 of whom also received cranial irradiation. There were 20 children who developed t-ML at a median of 2.3 years (range, 1.0-6.0 years), including 16 cases of acute myeloid leukemia, 3 myelodysplasia, and 1 chronic myeloid leukemia. Stratifying by protocol, the cumulative incidence functions differed (P =.017) according to the use of G-CSF and irradiation: 6-year cumulative incidence (standard error) of t-ML of 12.3% (5.3%) among the 44 children who received irradiation without G-CSF, 11.0% (3.5%) among the 85 children who received G-CSF but no irradiation, 7.1% (7.2%) among the 14 children who received irradiation plus G-CSF, and 2.7% (1.3%) among the 269 children who received neither irradiation nor G-CSF. Even when children receiving irradiation were excluded, the incidence was still higher in those receiving G-CSF (P =.019). In the setting of intensive antileukemic therapy, short-term use of G-CSF may increase the risk of t-ML.

Detection, isolation, and stimulation of quiescent primitive leukemic progenitor cells from patients with acute myeloid leukemia (AML)

Although many acute myeloid leukemia (AML) colony-forming cells (CFCs) and long-term culture-initiating cells (LTC-ICs) directly isolated from patients are actively cycling, quiescent progenitors are present in most samples. In the current study, (3)H-thymidine ((3)H-Tdr) suicide assays demonstrated that most NOD/SCID mouse leukemia-initiating cells (NOD/SL-ICs) are quiescent in 6 of 7 AML samples. AML cells in G(0), G(1), and S/G(2)+M were isolated from 4 of these samples using Hoechst 33342/pyroninY staining and cell sorting. The progenitor content of each subpopulation was consistent with the (3)H-Tdr suicide results, with NOD/SL-ICs found almost exclusively among G(0) cells while the cycling status of AML CFCs and LTC-ICs was more heterogeneous. Interestingly, after 72 hours in serum-free culture with or without Steel factor (SF), Flt-3 ligand (FL), and interleukin-3 (IL-3), most G(0) AML cells entered active cell cycle (percentage of AML cells remaining in G(0) at 72 hours, 1.2% to 37%, and 0% to 7.6% in cultures without and with growth factors [GFs], respectively) while G(0) cells from normal lineage-depleted bone marrow remained quiescent in the absence of GF. All 4 AML samples showed evidence of autocrine production of 2 or more of SF, FL, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF). In addition, 3 of 4 samples contained an internal tandem duplication of the FLT3 gene. In summary, quiescent leukemic cells, including NOD/SL-ICs, are present in most AML patients. Their spontaneous entry into active cell cycle in short-term culture might be explained by the deregulated GF signaling present in many AMLs.

Licensure of gemtuzumab ozogamicin for the treatment of selected patients 60 years of age or older with acute myeloid leukemia in first relapse

This paper discusses background information and the body of clinical data that has been accumulated to demonstrate the efficacy and safety of gemtuzumab ozogamicin (Mylotarg, Wyeth Pharmaceuticals, Philadelphia, PA). Based on these data, gemtuzumab ozogamicin was approved by the United States Food and Drug Administration for the treatment of patients with CD33-positive acute myeloid leukemia in first relapse who are 60 years of age or older and who are not considered candidates for other cytotoxic chemotherapy. The recommended dosage of gemtuzumab ozogamicin is 9 mg/m2, administered as a 2-hour intravenous infusion for a total of 2 doses with 14 days between doses.

Antibody-targeted chemotherapy of older patients with acute myeloid leukemia in first relapse using Mylotarg (gemtuzumab ozogamicin)

We analyzed the safety and efficacy of Mylotarg (gemtuzumab ozogamicin, an antibody-targeted chemotherapy consisting of a humanized anti-CD33 antibody linked to calicheamicin, a potent antitumor antibiotic) in the treatment of 101 patients > or =60 years of age with acute myeloid leukemia (AML) in untreated first relapse in three open-label trials. Mylotarg is administered as a 2-h intravenous infusion at 9 mg/m(2) for two doses with 14 days between doses. The overall remission rate was 28%, with complete remission (CR) in 13% of patients and complete remission with incomplete platelet recovery (CRp) in 15%. Median survival was 5.4 months for all patients and 14.5 months and 11.8 months for patients achieving CR and CRp, respectively. CD33 antigen is present on normal hematopoietic progenitor cells; thus, an expected high incidence of grade 3 or 4 neutropenia (99%) and thrombocytopenia (99%) was observed. The incidences of grade 3 or 4 elevations of bilirubin and hepatic transaminases were 24% and 15%, respectively. There was a low incidence of grade 3 or 4 mucositis (4%) and infections (27%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Mylotarg is an effective treatment for older patients with CD33-positive AML in first relapse and has acceptable toxicity.

Timed sequential chemotherapy with concomitant granulocyte colony-stimulating factor for high-risk acute myelogenous leukemia: a single arm clinical trial

BACKGROUND

The timed-sequential chemotherapy regimen consisting of etoposide, mitoxantrone and cytarabine (EMA) is an effective therapy for relapsed or refractory acute myelogenous leukemia (AML). We postulated that granulocyte colony-stimulating factor (G-CSF) might enhance the cytotoxicity of EMA by increasing the proportion of leukemic blasts in S-phase. We added G-CSF to EMA (EMA-G) for therapy of advanced high-risk AML patients.

METHODS

High-risk AML was defined as refractory, relapsed or secondary to either an antecedent hematologic disorder or exposure to cytotoxic agents. The patients were treated with one course of EMA-G consisting of mitoxantrone and cytarabine on days 1-3, and etoposide and cytarabine on days 8-10. G-CSF was started on day 4 and continued until absolute neutrophil count recovered.

RESULTS

Thirty patients were enrolled. The median age was 51 years (range, 25-75). Seventeen (61%) patients had unfavorable cytogenetic karyotypes. Twenty (69%) patients had secondary AML. Ten (34%) had relapsed disease. Four (14%) had refractory AML. Three (10%) patients died from febrile neutropenia and sepsis. Major non-hematologic toxicity included hyperbilirubimenia, renal insufficiency, mucositis, diarrhea, nausea and vomiting, skin rash. A complete remission was achieved in 13 (46%) patients. Median overall survival was 9 months (range, 0.5-66). Median relapse-free survival (RFS) for those who had a CR was 3 months (range, 0.5-63) with RFS censored at the time of allogeneic bone marrow transplantation or peripheral stem cell transplantation for 6 of the patients.

CONCLUSIONS

EMA-G is a safe and efficacious option for induction chemotherapy in advanced, high-risk AML patients. The activity of EMA may be increased if applied in patients with less advanced disease.

Acute and long-term toxicities associated with gemtuzumab ozogamicin (Mylotarg) therapy of acute myeloid leukemia

Gemtuzumab ozogamicin (Mylotarg) targets leukemia cells that express CD33 by means of a humanized anti-CD33 monoclonal antibody conjugated to a modified antitumor antibiotic, calicheamicin. The effects of gemtuzumab ozogamicin (given intravenously at a dose of 9 mg/m2 for 2 doses separated by 2 weeks) have been evaluated in 3 phase II studies involving patients (n = 188) with acute myeloid leukemia (AML) in first relapse. Interim analysis has revealed that 30% of patients achieved remission, characterized by < or = 5% blasts in the marrow, neutrophil count > or = 1500/microL, hemoglobin > or = 9 g/dL, and independence from red blood cell and platelet transfusion. Grade 3/4 acute toxicities included nausea or vomiting (11%); elevated serum aminotransferase enzyme (16%) and bilirubin (26%) levels; and infusion-related chills (9%), fever (6%), and hypotension (5%). As predicted with CD33-targeted therapy, most patients had neutropenia (98%) and thrombocytopenia (99%). However, the incidence of grade 3/4 bleeding events (14%) and infection rates (pneumonia, 7%; sepsis, 15%) was low. No patients were reported to have treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Veno-occlusive disease (VOD) after gemtuzumab ozogamicin treatment (but prior to other therapies) occurred in 2% of patients (4/188), and the VOD-related death rate was < 1% (1/188). Prior hematopoietic stem cell transplant may be a risk factor for VOD (P = 0.002, univariate analysis). Gemtuzumab ozogamicin is a safe and effective treatment in carefully selected patients with AML in first relapse.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) priming with successive concomitant low-dose Ara-C for elderly patients with secondary/refractory acute myeloid leukemia or advanced myelodysplastic syndrome

Patients with advanced MDS and secondary AML respond poorly to chemotherapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) can stimulate proliferation of leukemic blasts and sensitize these cells to the cytotoxic effects of S-phase-specific drugs. This is the first report of safety and efficacy of GM-CSF prior to and during cytarabine in a low-dose, intermittent regimen for elderly patients with poor risk acute myelogenous leukemia or myelodysplastic syndrome. Twenty patients, age 68 to 86 years, each received 250 microg/m2 of GM-CSF (Sargramostatin; Immunex, Seattle, WA, USA) subcutaneously (s.c.) or intravenously (i.v.) for 3 days followed by GM-CSF at the same dose and cytarabine 100 mg/m2 i.v. for 3 days. GM-CSF and cytarabine were both administered for 3 days during weeks 2 and 3 followed by a 3-week rest period. Rates of CR and PR were 20% and 40%, respectively. These included clinically significant resolution of cytopenias and transfusion requirements. Many of the responding patients had been heavily pretreated prior to enrollment. One- and 2-year survival estimates are 44% and 19%, respectively. Myelosuppression was the most significant toxicity. Our findings suggest that this novel combination of GM-CSF with sequential and concomitant low-dose cytarabine can benefit patients with poor risk myeloid malignancies.

Efficacy and safety of gemtuzumab ozogamicin in patients with CD33-positive acute myeloid leukaemia in first relapse

Gemtuzumab ozogamicin (CMA-676, Mylotarg, an antibody-targeted chemotherapy agent, was recently approved by the FDA for the treatment of patients with CD33+ acute myeloid leukaemia (AML) in first relapse who are 60 years of age or older and who are not considered candidates for other types of cytotoxic chemotherapy. In combined Phase II studies of 142 patients with CD33+ AML in first relapse, gemtuzumab ozogamicin monotherapy was associated with a 30% overall response rate. While treated patients had relatively high incidences of myelosuppression, grade 3 or grade 4 hyperbilirubinaemia (23%) and elevated hepatic transaminases (17%), the incidences of grade 3 or grade 4 mucositis (4%) and infections (28%) were low compared with what might be expected in association with conventional chemotherapeutic treatment. In contrast with the usual in-patient administration of cytarabine and anthracycline-containing induction regimens, a large number of patients were treated with gemtuzumab ozogamicin as outpatients (38% and 41% for the first and second doses, respectively). Two prognostic factors for patients with AML in first relapse, age and duration of complete remission, had relatively little effect on response rates to gemtuzumab ozogamicin. Preliminary data in pediatric patients also suggest the immunoconjugate to be reasonably well tolerated. Studies of gemtuzumab ozogamicin in combination with anthracycline and cytarabine are underway. Gemtuzumab ozogamicin, administered to patients with CD33+ AML in first relapse, has shown overall response rates comparable to conventional agents and a safety profile that appears to be favourable.