Combination of mitoxantrone and etoposide in refractory acute myelogenous leukemia--an active and well-tolerated regimen

Venetoclax combined with hypomethylating agents and the CAG regimen in relapsed/refractory AML: a single-center clinical trial

Objective

This study aimed to evaluate the efficacy and safety of venetoclax in combination with hypomethylating agents and CAG (VEN-DCAG) regimens in patients with relapsed/refractory acute myeloid leukemia (R/R AML).

Methods

The treatment response was analyzed by retrospective methods in R/R AML patients treated with the VEN-DCAG regimen at our institution. This included, but was not limited to, CR/CRi (complete remission/complete remission with incomplete hematologic recovery) rate, measurable residual disease (MRD) negative rate, and overall survival (OS).

Results

20 patients with R/R AML were recruited, with a median age of 40 years (10-70), 11 of whom were male (55%), and a median follow-up of 10.4 months (0.7-21.8). The overall response rate (ORR) after receiving 1 course of VEN-DCAG was 90% (18/20), with 17 (85%) CR/CRi (10 MRD-CR), 1 (5%) PR, and 2 (10%) NR. Subsequently, 12 patients (7 MRD-CR, 4 MRD+CR, 1 NR) were treated with the VEN-DCAG regimen, and 3 MRD+CR patients turned negative, and 13 patients finally achieved MRD-CR. Among them, 7 patients were in the relapse group, all achieving CR/CRi (6 MRD-CR), and 13 patients in the refractory group, with 10 CR/CRi (7 MRD-CR). The ORR for patients in the relapse and refractory groups was 100% (7/7) and 84.6% (11/13), respectively. Further, all patients experienced adverse events (AEs) of varying degrees of severity, with hematologic AEs primarily consisting of myelosuppression, while non-hematologic AEs were more common in the form of fever, gastrointestinal distress, and infections. 11 patients were followed up with bridging allogeneic hematopoietic stem cell transplantation (allo-HSCT) therapy. At the last follow-up, 11 patients (7 MRD-CR, 4 MRD+CR) who received allo-HSCT, 1 (MRD+CR) died, and 9 patients (6 MRD-CR, 1 PR, 2 NR) who did not receive allo-HSCT, 5 (2 MRD-CR, 1 PR, 2 NR) died as well.

Conclusion

The VEN-DCAG regimen may be an effective treatment option for R/R AML patients, with high ORR and MRD negative remission rates in both the relapsed and refractory groups. It is recommend that patients should be bridged to allo-HSCT as soon as possible after induction to CR by the VEN-DCAG regimen, which can lead to a significant long-term survival benefit.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2300075985.

Haploidentical Natural Killer Cell Therapy as an Adjunct to Stem Cell Transplantation for Treatment of Refractory Acute Myeloid Leukemia

Refractory acute myeloid leukemia (AML), defined as failure of two cycles of induction therapy at diagnosis or of one cycle at relapse, represents a subgroup with poor outcomes. Haploidentical natural killer cell (NK) therapy is a strategy that is being explored in refractory malignancies. Historically, at our center, patients with refractory AML have been treated with cytoreductive therapy (fludarabine + cytosine + granulocyte colony-stimulating factor ± idarubicin or mitoxantrone + etoposide) followed by 1-week rest and then reduced-intensity transplant with fludarabine + melphalan. We used the same backbone for this trial (CTRI/2019/02/017505) with the addition of CD56-positive cells from a family donor infused 1 day after the completion of chemotherapy. CD56-positive selection was done using a CliniMACS Prodigy system (Miltenyi Biotec, Bergisch Gladbach, Germany) followed by overnight incubation in autologous plasma with 2 micromolar arsenic trioxide and 500 U/mL of interleukin-2. From February 2019, 14 patients with a median age of 29 years (interquartile range [IQR]: 16.5-38.5) were enrolled in this trial. Six were females. Six had primary refractory AML while eight had relapsed refractory AML. The median CD56-cell dose infused was 46.16 × 106/kg (IQR: 25.06-70.36). One patient withdrew consent after NK cell infusion. Of the 13 patients who proceeded to transplant, five died of immediate post-transplant complications while two did not engraft but were in morphologic leukemia-free state (both subsequently died of infective complications after the second transplant). Of the remaining six patients who engrafted and survived beyond 1 month of the transplant, two developed disease relapse and died. The remaining four patients are alive and relapse free at the last follow-up (mean follow-up duration of surviving patients is 24 months). The 2-year estimated overall survival for the cohort was 28.6% ± 12.1% while the treatment-related mortality (TRM) with this approach was 38.5% ± 13.5%. Haploidentical NK cell therapy as an adjunct to transplant is safe and needs further exploration in patients with AML. For refractory AML, post-transplant NK infusion and strategies to reduce TRM while using pre-transplant NK infusion merit exploration.

Characteristics and Outcomes of Adult Patients in the PETHEMA Registry with Relapsed or Refractory FLT3-ITD Mutation-Positive Acute Myeloid Leukemia

This retrospective study investigated outcomes of 404 patients with relapsed/refractory (R/R) FMS-like tyrosine kinase 3 (FLT3)-internal tandem duplication (ITD) acute myeloid leukemia (AML) enrolled in the PETHEMA registry, pre-approval of tyrosine kinase inhibitors. Most patients (63%) had received first-line intensive therapy with 3 + 7. Subsequently, patients received salvage with intensive therapy (n = 261), non-intensive therapy (n = 63) or supportive care only (n = 80). Active salvage therapy (i.e., intensive or non-intensive therapy) resulted in a complete remission (CR) or CR without hematological recovery (CRi) rate of 42%. More patients achieved a CR/CRi with intensive (48%) compared with non-intensive (19%) salvage therapy (p < 0.001). In the overall population, median overall survival (OS) was 5.5 months; 1- and 5-year OS rates were 25% and 7%. OS was significantly (p < 0.001) prolonged with intensive or non-intensive salvage therapy compared with supportive therapy, and in those achieving CR/CRi versus no responders. Of 280 evaluable patients, 61 (22%) had an allogeneic stem-cell transplant after they had achieved CR/CRi. In conclusion, in this large cohort study, salvage treatment approaches for patients with FLT3-ITD mutated R/R AML were heterogeneous. Median OS was poor with both non-intensive and intensive salvage therapy, with best long-term outcomes obtained in patients who achieved CR/CRi and subsequently underwent allogeneic stem-cell transplant.

Mitochondrial metabolism as a target for acute myeloid leukemia treatment

Acute myeloid leukemias (AML) are a group of aggressive hematologic malignancies resulting from acquired genetic mutations in hematopoietic stem cells that affect patients of all ages. Despite decades of research, standard chemotherapy still remains ineffective for some AML subtypes and is often inappropriate for older patients or those with comorbidities. Recently, a number of studies have identified unique mitochondrial alterations that lead to metabolic vulnerabilities in AML cells that may present viable treatment targets. These include mtDNA, dependency on oxidative phosphorylation, mitochondrial metabolism, and pro-survival signaling, as well as reactive oxygen species generation and mitochondrial dynamics. Moreover, some mitochondria-targeting chemotherapeutics and their combinations with other compounds have been FDA-approved for AML treatment. Here, we review recent studies that illuminate the effects of drugs and synergistic drug combinations that target diverse biomolecules and metabolic pathways related to mitochondria and their promise in experimental studies, clinical trials, and existing chemotherapeutic regimens.

Comparison of salvage chemotherapy regimens and prognostic significance of minimal residual disease in relapsed/refractory acute myeloid leukemia

We compared the outcomes of salvage chemotherapy in 146 patients with relapsed (57.5%) or refractory (42.5%) AML who received CLAG-M (51%), MEC (39%) or CLAG (10%). Minimal residual disease (MRD) was assessed by flow cytometry. Bivariate, Kaplan-Meier, and Cox regression analyses were conducted. Complete remission (CR) rate of 46% (CLAG-M 54% versus MEC/CLAG 40%, p = .045) was observed with MRD-negative CR of 33% (CLAG-M 39% versus MEC/CLAG 22%, p = .042). Median overall survival (OS) was 9.7 months; the longest OS occurred with CLAG-M (13.3, 95%CI 2.4-24.3) versus MEC (6.9, 95%CI 2.9-10.9) or CLAG (6.2, 95%CI 2.4-12.6) (p = .025). When adjusted for age, gender, relapsed/refractory AML, poor risk AML, MRD, chemotherapy and transplant, CLAG-M (HR 0.63, 95% CI 0.40-0.98, p = .042), MRD-negativity (HR 0.15, 95% CI 0.07-0.30, p < .001) and transplant (HR 0.22, 95% CI 0.13-0.39, p < .001) were associated with higher OS. Our findings confirm that CLAG-M is a reasonable salvage regimen for RR-AML followed by transplant.

Implementation of a pharmacy-managed program for the transition of chemotherapy to the outpatient setting

PURPOSE

Implementation of a pharmacy-managed program for the transition of chemotherapy to the outpatient setting is described.

SUMMARY

The University of Arizona Cancer Center and Banner-University Medical Center Tucson are affiliated not-for-profit academic medical centers in Tucson, Arizona, whose facilities include a hospital and ambulatory care clinics that maintain 3 outpatient infusion centers. The cancer center pharmacy currently employs 25 pharmacists, with 4 clinical pharmacists serving both the inpatient and outpatient treatment sites. A multidisciplinary team of staff members was assembled to address the transition of chemotherapy from inpatient to outpatient that included physicians, ambulatory clinical oncology pharmacists, finance, social workers, pharmacy staff, nursing staff, and information technology. The program was initiated in May 2014, with a 2-year postimplementation evaluation of our transition of chemotherapy to the outpatient setting. Chemotherapy order sets were developed in our electronic medical record for transitioning rituximab to the outpatient setting for inpatient chemotherapy orders as well as transitioning leukemia, lymphoma, and solid tumor chemotherapy regimens to be administered in the outpatient setting. Eighteen rituximab-containing regimens and 14 chemotherapy protocols were switched to the outpatient setting, with numerous variants of these regimens also created for outpatient only administration. The realized savings for high-cost chemotherapy transitioned to the outpatient setting with rituximab and clofarabine was $1,902,890. Over 747 inpatient bed days were saved, with an approximated cost savings to the health system of $1,402,866, with a cumulative cost savings to our health system of $3,305,756.

CONCLUSION

This model for transitioning chemotherapy from the hospital to the outpatient setting enhanced access to care, decreased bed utilization in the hospital, and improved clinical and financial metrics.

Efficacy and Feasibility of Allogeneic Hematopoietic Stem-Cell Transplantation in the Treatment of Refractory Acute Myeloid Leukemia

BACKGROUND

Refractory acute myeloid leukemia (AML) includes AML includes failure of disease to respond to standard induction chemotherapy, relapse within 6 months after first CR, and 2 or more relapses. The outcome of these patients is usually very poor; only a small proportion can be rescued by allogenic hematopoietic stem-cell transplantation (allo-HSCT). The aim of this study was to evaluate the efficacy and feasibility of allo-HSCT in patients with refractory AML.

PATIENTS AND METHODS

We retrospectively analyzed the clinical outcome of 91 patients who were diagnosed with treatment-refractory AML at Hacettepe University Hospital between January 2002 and June 2018. Patients' disease status included refractory AML, defined as failure to respond to standard induction chemotherapy and relapse within 6 months after first complete remission.

RESULTS

The median follow-up was 12 months (range, 0.5-184 months) for the entire group. Kaplan-Meier estimates of the 3-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 67% and 12%, respectively. Additionally, the Kaplan-Meier estimates of 5-year overall survival for patients who underwent allo-HSCT and patients who received only salvage chemotherapy were 44% and 4%, respectively (P < .001). Complete remission was obtained in 25 patients (83.3%) who underwent allo-HSCT; however, the disease of only 3 patients (3.8%) exhibited complete response after salvage chemotherapy.

CONCLUSION

Allo-HSCT is still the best-known treatment option with curative potential in patients with treatment-refractory AML. Therefore, all efforts should be made in an attempt to find a suitable matched donor in order to perform allo-HSCT.

A phase I-II study of plerixafor in combination with fludarabine, idarubicin, cytarabine, and G-CSF (PLERIFLAG regimen) for the treatment of patients with the first early-relapsed or refractory acute myeloid leukemia

Clinical outcomes of patients with acute myeloid leukemia (AML) showing the first primary refractory or early-relapsed disease remain very poor. The Programa Español de Tratamientos en Hematología (PETHEMA) group designed a phase I-II trial using FLAG-Ida (fludarabine, idarubicin, cytarabine, and G-CSF) plus high-dose intravenous plerixafor, a molecule inducing mobilization of blasts through the SDF-1α-CXCR4 axis blockade and potentially leading to chemosensitization of the leukemic cells. We aimed to establish a recommended phase 2 dose (RP2D) of plerixafor plus FLAG-Ida, as well as the efficacy and safety of this combination for early-relapsed (first complete remission (CR/CRi) < 12 months) or primary refractory AML. Between 2012 and 2015, 57 patients were enrolled, and 41 received the RP2D (median age 52 years [range, 18-64]). Among these patients, 20 (49%) achieved CR/CRi, and 3 (7%) died during induction. CR/CRi rate was 50% (13/26) among primary refractory and 47% (7/15) among early relapse. Overall, 25 patients (61%) were allografted. Median overall and disease-free survivals were 9.9 and 13 months, respectively. In summary, the combination of plerixafor plus FLAG-Ida resulted in a relatively high CR/CRi rate in adult patients with primary refractory or early relapsed AML, with an acceptable toxicity profile and induction mortality rate, bridging the majority of patients to allogeneic stem cell transplantation. ClinicalTrials.gov Identifier: NCT01435343.

Mitoxantrone and Etoposide for the Treatment of Acute Myeloid Leukemia Patients in First Relapse

Relapsed acute myeloid leukemia (AML) represents a major therapeutic challenge. Achieving complete remission (CR) with salvage chemotherapy is the first goal of therapy for relapsed AML. However, there is no standard salvage chemotherapy. The current study evaluated outcomes and prognostic factors for achievement of CR in 91 AML patients in first relapse who were treated with the mitoxantrone-etoposide combination regimen. The overall response rate (CR and CRi) was 25%. Factors that were associated with a lower rate of CR included older age, shorter duration of first CR, low hemoglobin, and low platelet count. The median overall survival for all patients was 7.4 months. The survival of patients who achieved CR and underwent allogeneic hematopoietic cell transplantation (allo-HCT) was higher than those who achieved CR and did not undergo allo-HCT (35.3 months vs. 16.8 months, p = 0.057). The median duration of relapse-free survival was 12.7 months in the patients achieving CR. Older age at the time of AML relapse was associated with worse overall survival. The all-cause 4-week mortality rate was 4%, and the all-cause 8-week mortality rate was 13%. The findings of this study underscore the need for newer therapies, especially those that will improve the ability for patients with relapsed AML to achieve CR and to allow them to receive additional therapies.

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.

Relapsed and refractory pediatric acute myeloid leukemia: current and emerging treatments

Survival rates for children with acute myeloid leukemia (AML) exceed 60 % when modern, intensified chemotherapeutic regimens and enhanced supportive care measures are employed. Despite well-recognized improvements in outcomes, primary refractory or relapsed pediatric AML yields significant morbidity and mortality, and improved understanding of this obstinate population along with refined treatment protocols are urgently needed. Although a significant number of patients with refractory or relapsed disease will achieve remission, long-term survival rates remain poor, and efforts to identify therapies which will improve OS are under continuous investigation. The current fundamental goal of such investigation is the achievement of as complete a remission as possible without dose-limiting toxicities, and the progression to hematopoietic stem cell transplantation thereafter. In this review the scope of the problem of relapsed and refractory AML as well as current and emerging chemotherapy options will be discussed.

Update on optimal management of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a malignant accumulation of immature myeloid cells in the marrow, presenting with impaired hematopoiesis and its attendant complications, including bleeding, infection, and organ infiltration. Chromosomal abnormalities remain the most powerful predictors of AML prognosis and help to identify a subgroup with favorable prognosis. However, the majority of AML patients who are not in the favorable category succumb to the disease. Therefore, better efforts to identify those patients who may benefit from more aggressive and investigational therapeutic approaches are needed. Newer molecular markers aim at better characterizing the large group of intermediate-risk patients and to identify newer targets for therapy. A group that has seen little improvement over the years is the older AML group, usually defined as age ≥ 60. Efforts to develop less intensive but equally efficacious therapy for this vulnerable population are underway.

Anthracycline dose intensification in young adults with acute myeloid leukemia

The initial treatment for acute myeloid leukemia (AML) has remained largely unchanged for nearly 40 years. Our growing understanding of the molecular pathology of AML has resulted in improved measures to risk stratify patients by recurrent cytogenetic and molecular abnormalities without marked advancement in its initial treatment. The most common regimen consists of a 3-day course of an anthracycline and a 7-day infusion of cytarabine. This regimen has been employed across the globe in various iterations for many years with modest improvements in results yet this remains the first choice for the treatment of younger adults with AML. Despite this, the chemotherapeutic agents in this regimen are only now being fully understood. Recent evidence has suggested that dose intensification of anthracycline in young adults has a significant survival benefit. In this paper we review the evidence behind the use of anthracyclines in the initial induction of AML in younger adults focusing on the choice and dose of this long used drug combination.

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.

Candidate agents for papillary thyroid cancer identified by gene expression analysis

A better understanding of the molecular mechanisms involved in papillary thyroid cancer (PTC) is needed to manage these patients effectively. Our objectives were to expand our understanding of this disease, and to identify biologically active small molecules capable to reverse PTC. We downloaded gene expression data of PTC from Gene Expression Omnibus database and employed computational bioinformatics analysis to compare gene expression patterns with normal tissues. Small molecules that induced inverse gene changes to the PTC were identified. A total of 2,154 differentially expressed genes (DEGs) with a false discovery rate of 0.01 were identified. These 2,154 DEGs were significantly enriched in 17 pathways, including pathways associated with signal transduction, tumorigenesis and lipid or amino acid metabolism. In addition, we identified large amount of small molecules that capable to reverse PTC. We found a group of small molecules that can provide new ideas for the therapeutic studies in PTC. These drugs are clearly a direction that warrants additional consideration.

A phase I dose-escalation study of clofarabine in combination with fractionated gemtuzumab ozogamicin in patients with refractory or relapsed acute myeloid leukemia

Clofarabine and gemtuzumab ozogamicin (GO) are active agents against acute myeloid leukemia (AML), but have not previously been tested in combination. We conducted a phase I study to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLTs) of clofarabine when combined with GO in adult patients with relapsed or refractory AML. Twenty patients received clofarabine (10, 20 or 30 mg/m(2)) on days 1-5, with GO 3 mg/m(2)/day on days 1, 4 and 7. Common dose-limiting toxicities were prolonged myelosuppression and hepatotoxicity. Clofarabine 20 mg/m(2) was the MTD, but with a DLT rate of 0.38 (5/13) - a rate that is prohibitively high to recommend for phase II study. The overall response rate (complete response [CR] + complete response with incomplete hematologic recovery [CRi]) was 42% among all patients. Thus, this combination demonstrated activity in relapsed and refractory patients, but further testing of the combination using lower doses of GO may identify more favorable rates of toxicity while maintaining efficacy.

High dose cytarabine plus gemtuzumab ozogamicin for patients with relapsed or refractory acute myeloid leukemia: Cancer and Leukemia Group B study 19902

Gemtuzumab ozogamicin (GO), an anti-CD33 immunoconjugate, was combined with high dose cytarabine (HiDAC; cytarabine 3g/m(2) over 3h daily for 5 days) for adults with relapsed or refractory AML. HiDAC plus GO 9mg/m(2) on day 7 and 4.5mg/m(2) on day 14 was not tolerated, but HiDAC followed by GO 9mg/m(2) on day 7 was safe: 12/37 (32%) patients with relapsed AML achieved complete remission. Median overall survival was 8.9 months. No grade 4 hepatic veno-occlusive disease was observed. This regimen merits further study, both in this setting and as a remission consolidation therapy.

How I treat acute myeloid leukemia

More than one quarter of a million adults throughout the world are diagnosed annually with acute myeloid leukemia (AML). Despite considerable progress during the past 3 decades in the therapy of AML, two-thirds of young adults and 90% of older adults still die of their disease. The reported median age has increased over the past few decades, mostly because of a greater willingness of physicians to diagnose and treat older patients, and now is 72 years. The greatest challenge is in this age group. However, much improvement in therapy is needed for all adults with AML. Recent advances in allogeneic transplantation, a better understanding of prognostic factors, and development of targeted agents have only modestly improved overall outcome when large populations of patients are considered. Although an explosion in knowledge about the molecular pathogenesis of AML has outpaced treatment advances, such insights hold promise for the development of new therapies directed at specific molecular abnormalities that perturb malignant cell survival pathways. The current approach in 2010 to the management of this disease is presented through a discussion of illustrative cases.

Diagnosis and management of acute myeloid leukemia in adults: recommendations from an international expert panel, on behalf of the European LeukemiaNet

In 2003, an international working group last reported on recommendations for diagnosis, response assessment, and treatment outcomes in acute myeloid leukemia (AML). Since that time, considerable progress has been made in elucidating the molecular pathogenesis of the disease that has resulted in the identification of new diagnostic and prognostic markers. Furthermore, therapies are now being developed that target disease-associated molecular defects. Recent developments prompted an international expert panel to provide updated evidence- and expert opinion–based recommendations for the diagnosis and management of AML, that contain both minimal requirements for general practice as well as standards for clinical trials. A new standardized reporting system for correlation of cytogenetic and molecular genetic data with clinical data is proposed.

Acute myelogenous leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with outcomes dependent upon several factors, including patient age, karyotype, mutational status, and comorbid conditions. For younger patients, approximately 60% to 80% achieve complete remission with standard therapy involving cytarabine and an anthracycline. However, only 20% to 30% have long-term disease-free survival. For adults older than 60 years of age, only 40% to 55% achieve a complete remission, with dismal long-term survival rates. Unfortunately, the median age at diagnosis for AML is 70 years. Significant advances in our understanding of the molecular biology of AML have led to newer therapies that specifically target molecular abnormalities. Examples of such therapies include the immunoconjugate gemtuzumab ozogamicin, FMS-like tyrosine kinase 3 inhibitors, farnesyl transferase inhibitors, histone deacetylase inhibitors, DNA hypomethylating agents, multidrug-resistance inhibitors, BCL-2 inhibitors, antiangiogenesis agents, and various nucleoside analogs. This review summarizes the standard treatments for AML and discusses the role of novel therapies.

Novel strategies for relapsed and refractory acute myeloid leukemia

PURPOSE OF REVIEW

Treatment for relapsed or refractory acute myeloid leukemia remains a major challenge for the leukemia community. Although several approaches have been tested in phase II study designs, few comparative data exist to guide treatment choices. We searched the recent literature in Medline, EMBASE and BIOSIS, and abstracts from the American Society of Hematology and American Society of Clinical Oncology published between 2005 and 2007. We reviewed each report to identify studies that used a phase II or III design and that included a majority of adults with non-M3 acute myeloid leukemia described as 'relapsed' or 'refractory'.

RECENT FINDINGS

Several studies utilized novel cytotoxic chemotherapies, immunotherapies, epigenetic agents, and small molecule inhibitors. It is not possible to identify a single regimen or approach as the standard of care in relapsed and refractory acute myeloid leukemia. New and promising approaches are being explored, however.

SUMMARY

Outcomes in patients treated for relapsed or refractory acute myeloid leukemia remain inadequate. Striking a balance between the treatment-related mortality associated with salvage therapies, response rates of salvage regimens, and the likelihood of long-term disease-free survival are critical in planning a treatment approach for the individual patient with relapsed or refractory acute myeloid leukemia.

Sequential response-adapted induction and consolidation regimens idarubicin/cytarabine and mitoxantrone/etoposide in adult acute myelogenous leukemia: 10 year follow-up of a study by the Canadian Leukemia Studies Group

PURPOSE

The Canadian Leukemia Studies Group (CLSG) sought to test the safety and efficacy of response-adapted, non-cross resistant chemotherapy in de novo acute myeloid leukemia (AML). The combinations of idarubicin 12 mg/m(2)/d on days 1 - 3 and Ara-C (200 mg/m(2)/d) on days 1 - 7 (IDAC) followed by mitoxantrone 10 mg/m(2)/day, and etoposide 100 mg/m(2)/day, on days 1 - 5 (NOVE) were used according to patient response to induction and consolidation.

PATIENTS AND METHODS

In this multi-centre open-label phase II study, 140 patients up to age 80 were given induction with IDAC. Patients were entered between March 1993 and August 1995. If patients had persistent blasts at day 14 or on recovery, they were given NOVE. As consolidation, patients achieving complete remission (CR) with IDAC were given 1 further cycle of IDAC and 1 cycle of NOVE. Patients achieving CR after NOVE were given 2 further cycles of NOVE.

RESULTS

76% of all patients achieved remission after IDAC +/- NOVE, 81% in patients aged < or =60 years and 67% in patients aged >60. Overall, induction mortality was 11% and toxicity was similar to other cooperative group studies. Median follow-up was 104.0 months with 95% CI: (100.0, 105.2). Median overall survival (OS) in responding patients < or =60 was not reached: of the 79 responders < or =60, 35 died. The median disease free survival (DFS) in these responding patients was 22.7 (14.9, na) months. Median OS and DFS in responding patients >60 was 10.0 (7.3, 15.2) months and 7.5 (6.2, 15.2) months, respectively.

CONCLUSION

The results of this trial are very encouraging and suggest that there may be long-term benefit to this method. On the basis of these results, a randomized phase III trial has been performed.

Inhibition of efflux transporter ABCG2/BCRP does not restore mitoxantrone sensitivity in irinotecan-selected human leukemia CPT-K5 cells: evidence for multifactorial multidrug resistance

It has been shown that the human acute lymphoblastic leukemia (ALL) T cell line (RPMI 8402) selected with irinotecan (CPT-11) is transformed to a multidrug resistant (MDR) phenotype (CPT-K5) with cross-resistance to mitoxantrone (MX). Since MX is a well-documented substrate for the efflux transporter breast cancer resistant protein (BCRP/ABCG2), we assessed the contribution of drug efflux to MX resistance in CPT-K5 cells. Our results demonstrate that CPT-K5 cells had markedly higher expression levels of BCRP, negligible expression of MRP2 and P-gp, and lower intracellular retention of MX as compared to RPMI 8402 cells. Surprisingly, MX resistance in CPT-K5 cells was not reversed by the BCRP chemical inhibitor, novobiocin (NOV), or gene-specific siRNA, although intracellular MX concentrations were significantly increased when BCRP was functionally knocked down. These results suggest that up-regulation of BCRP plays a minimal role in conferring MX resistance to CPT-K5 cells, highlighting the existence of multiple, redundant mechanisms of drug resistance. The current results support the concept of "multifactorial multidrug resistance", a recently-described phenomenon that ascribes multidrug resistance to many possible cellular mechanisms, not only by efflux drug transporters.

Improved treatment results for childhood acute myeloid leukemia in Taiwan

To improve treatment results for children with de novo acute myeloid leukemia (AML), we introduced a novel protocol, Taiwan Pediatric Oncology Group-AML-97A, for AML other than acute promyelocytic leukemia (APL), for which modified conventional protocols were used. From January 1, 1997, to December 31, 2002, 141 children younger than 17 years old with de novo AML were enrolled. In total, 117 patients with non-APL AML were treated with induction therapy of idarubicin and cytarabine (Ara-C), postremission therapy with high-dose Ara-C - containing regimens for four monthly courses, and moderate-dose therapy with idarubicin and Ara-C for four monthly courses. The first 19 patients with APL were treated with all-trans retinoic acid, idarubicin and Ara-C, with the remaining five patients receiving all-trans retinoic acid and idarubicin, followed by maintenance therapy for 2 years. Stem cell transplantation was performed in 29 patients in first remission with a similar outcome as chemotherapy alone. The remission rate in the AML-97A study was 90%, the 5-year survival 51 +/- 5.3% (s.e.) and the 5-year event-free survival 50 +/- 4.8%; for APL, these were 100%, 86 +/- 7.0, and 75 +/- 9.8%. For the whole group, the 5-year survival was 57 +/- 4.7% and the 5-year event-free survival 54 +/- 4.4%. The AML-97A regimen was well tolerated.

FLAG-IDA in the treatment of refractory/relapsed acute myeloid leukemia: single-center experience

We evaluated the efficacy and toxicity profiles of the combination of fludarabine, high-dose cytosine arabinoside (AraC), idarubicin, and granulocyte colony-stimulating factor (G-CSF) in refractory/relapsed acute myeloblastic leukemia (AML) patients. Between October 1998 and February 2002, 46 AML patients were treated with FLAG-IDA (fludarabine 30 mg/m(2), AraC 2 g/m(2) for 5 days, idarubicin 10 mg/m(2) for 3 days, and G-CSF 5 micro g/kg from day +6 until neutrophil recovery). Thirty patients were in relapse after conventional chemotherapy including cytarabine, etoposide, and daunorubicin or mitoxantrone according to the GIMEMA protocols. Four were in relapse after autologous peripheral stem cell transplantation and two after allogeneic bone marrow transplantation. Ten patients had refractory disease (after 10 days of standard doses of cytarabine, 3 days of mitoxantrone or daunorubicin, and 5 days of etoposide). Recovery of neutrophils and platelets required a median of 19 and 22 days from the start of therapy. Complete remission (CR) was obtained in 24 of 46 patients (52.1%) and 3 of 46 (6.6%) died during reinduction therapy: 2 due to cerebral hemorrhage and 1 due to fungemia ( Candida tropicalis). Fever >38.5 degrees C was observed in 40 of 46 patients (86.9%), 27 had fever of unknown origin (FUO) and 13 documented infections; 31 of 46 (67.3%) developed mucositis and 14 of 46 (30.4%) had grade 2 WHO transient liver toxicity. After achieving CR, 11 patients received allogeneic stem cell transplantation, 4 patients received autologous stem cell transplantation, 4 were judged unable to receive any further therapy, and 5 refused other therapy. Ten patients are at present in continuous CR after a median follow-up of 13 months (range: 4-24). In our experience, FLAG-IDA is a well-tolerated and effective regimen in relapsed/refractory AML. The toxicity is acceptable, enabling most patients to receive further treatment, including transplantation procedures.

A randomized trial of liposomal daunorubicin and cytarabine versus liposomal daunorubicin and topotecan with or without thalidomide as initial therapy for patients with poor prognosis acute myelogenous leukemia or myelodysplastic syndrome

BACKGROUND

Because angiogenesis may play a role in the pathogenesis of acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS), and thalidomide (Th) has shown significant anti-angiogenic activity, this study was designed to investigate the potential role of Th in the treatment of patients with AML and MDS and the possible role of a non-ara-C-containing regimen.

METHODS

Adults with AML or high-risk MDS and cytogenetic abnormalities other than inv (16), t(8;21), -Y or -X were randomized to receive liposomal daunorubicin (DNX) and ara-C (DA) or DNX and topotecan (DT). Within each arm, patients were randomized to receive chemotherapy alone (DA or DT) or with thalidomide (DATh or DTTh). Vascular endothelial growth factor (VEGF) plasma levels and microvascular density was measured before and after therapy. Eighty-four patients (median age, 65 years; range, 27-84 years) were treated.

RESULTS

None of 11 patients treated with DT or DTTh responded and these arms were closed. Seventeen of 37 patients treated with DA and 15 of 36 treated with DATh achieved an early complete remission. Median complete response duration was 38 and 34 weeks (P = 0.57) and median survival 35 and 28 weeks (P = 0.15), respectively. Patients with high pretreatment VEGF levels had an inferior survival. There was no significant difference in the changes in VEGF levels or microvascular density after treatment in patients who did versus those who did not receive thalidomide.

CONCLUSIONS

The authors concluded that thalidomide in combination with chemotherapy does not result in clinical benefit in patients with AML or high-risk MDS.

Outcome after induction chemotherapy for older patients with acute myeloid leukemia is not improved with mitoxantrone and etoposide compared to cytarabine and daunorubicin: a Southwest Oncology Group study

Complete remission and long-term survival rates are low for older adults treated for acute myeloid leukemia (AML). Because of favorable phase 2 data using mitoxantrone and etoposide, we conducted a phase 3 study (SWOG-9333) in which patients over 55 years of age with previously untreated AML were randomized to receive mitoxantrone (10 mg/m(2) per day x 5) and etoposide (100 mg/m(2) per day x 5) [ME], or cytarabine (200 mg/m(2) per day x 7) and daunorubicin (45 mg/m(2) per day x 3) [AD] as induction therapy. The randomization was stratified by age, onset of leukemia, and multidrug resistance phenotype. Over a 4-year period, 328 eligible patients from 66 institutions were enrolled. The complete remission rate was 34% (95% confidence interval [CI] 26%-41%) for patients in the ME and 43% (CI 35%-51%) for patients in the AD treatment arm (one-tailed P value.96). The rates of resistant disease were 43% (CI 35%-51%) and 34% (CI 27%-42%), respectively, for the 2 treatment arms (one-tailed P value.95). The estimated overall survival at 2 years was 11% (CI 6%-15%) and 19% (CI 12%-25%) for patients randomized to ME and to AD induction therapy, respectively (one-tailed P value.99). After accounting for the independent prognostic factors associated with survival (karyotype, performance status, age, white blood cell count), exploratory analysis suggested there was a worse survival for patients who received ME compared with AD induction therapy (2-tailed P value.0066). We conclude that the results of our study do not demonstrate any benefit to the use of ME induction chemotherapy instead of AD in older patients with AML.

The treatment of acute myeloid leukemia in first relapse: a comprehensive review of the literature

Twenty years of published literature was reviewed for chemotherapy regimens used to treat patients with acute myeloid leukemia (AML) in first relapse. Thirty-one trials containing at least 20 patients in first relapse and information on patient age, duration of first complete remission (CR1), and rate of second complete remission (CR2) were analyzed. These trials included 10 retrospective studies with CR2 rates ranging from 30 to 64%, two phase II single-agent studies with CR2 rates of 8 and 25%, 15 phase II combination-agent studies with CR2 rates ranging from 14 to 87%, and four phase III randomized studies with CR2 rates ranging from 40 to 89%. When reported, median duration of CR2 was < or = 14 months and overall median survival was < or = 12 months. The probability of 3-year survival ranged from 8 to 29%. Combination therapies resulted in higher CR2 rates but were associated with longer duration of myelosuppression and greater incidence of mucositis. None of the reviewed regimens provided durable remissions for the majority of AML patients in first relapse. The CR2 rates were closely associated with age and duration of CR1. Therefore, considering the poor clinical outcomes of patients with AML in first relapse, improved therapies need to be developed.

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.

FLAG-IDA regimen (fludarabine, cytarabine, idarubicin and G-CSF) in the treatment of patients with high-risk myeloid malignancies

Forty-five patients with high-risk myeloid malignancies (32 acute myeloid leukemia and 13 high-risk myelodysplastic syndromes) were treated with fludarabine, cytarabine, idarubicin, and G-CSF (FLAG-IDA). Twenty-four (53%) patients achieved complete remission (CR), and five (11%) partial remission. Infection predominantly with pulmonary involvement was the most common regimen-related toxicity. Mucositis (15 patients) and pulmonary toxicity (19 patients) were the most frequently observed non-hematologic side effects. There were four early deaths and 12 patients presented with resistant disease. Overall survival (OS) at 12 months was 40%. The FLAG-IDA regimen shows evident antileukemic activity in patients with high-risk myeloid malignancies with acceptable toxicity.

Insights from pre-clinical studies for new combination treatment regimens with the Bcr-Abl kinase inhibitor imatinib mesylate (Gleevec/Glivec) in chronic myelogenous leukemia: a translational perspective

Clinical phase I/II studies with the Abl kinase inhibitor imatinib mesylate (Gleevec/Glivec, formerly STI571) for the treatment for chronic myelogenous leukemia (CML) demonstrated the safety and the remarkable efficacy of this molecularly targeted agent. However, a significant proportion of patients treated in the chronic phase of the disease after having failed interferon alpha (IFN) remain predominantly Philadelphia chromosome positive (Ph(+)), suggesting a risk of later relapses. Furthermore, results in blast crisis patients revealed a high frequency of relapses or resistance to imatinib. To circumvent resistance, improve response rates, or prolong survival, pre-clinical evaluations of combinations of imatinib with other agents have been pursued. Some of these have already been translated into clinical studies. Here, we first summarize evidence from pre-clinical studies on new combination regimens with imatinib in the treatment of CML. Second, we analyze preliminary clinical data of ongoing combination studies. Finally, we provide a summary of approaches that use novel antileukemic agents with molecularly characterized modes of action.

Treatment of refractory and relapsed acute myelogenous leukemia

Refractory and relapsed disease occurs in most acute myelogenous leukemia patients. Salvage chemotherapy offers a 30-70% chance of a second complete remission. Unfortunately, this second remission is usually short lived and salvage chemotherapy is rarely curative. Allogeneic bone marrow transplant, either human leukocyte antigen (HLA)-sibling matched or matched unrelated donor, is the only treatment to offer long-term disease-free survival and possible cure. Many patients will be ineligible for allogeneic bone marrow transplant. A conjugated antiCD33 monoclonal antibody, gemtuzumab ozogamicin, has recently been approved for use in relapsed and refractory acute myelogenous leukemia patients. New and novel agents are also undergoing trials in an attempt to improve on the overall poor outcomes.

Treatment of refractory acute leukemia with timed sequential chemotherapy using topotecan followed by etoposide + mitoxantrone (T-EM) and correlation with topoisomerase II levels

A phase I/II clinical study evaluated 17 patients with refractory/recurrent acute leukemia treated with 1.5 mg/m2/day topotecan on days 1-3 followed by etoposide (100 mg/m2/day)+mitoxantrone (10 mg/m2/day) on days 4, 5 and 9, 10. Timed sequential chemotherapy using the topoisomerase I-inhibitor topotecan before the topoisomerase II-inhibitors, etoposide+mitoxantrone (T-EM) treatment is proposed to induce topoisomerase II protein levels and potentiate the cytotoxic activity of the topoisomerase II-directed drugs. Fourteen patients had refractory and three had recurrent acute leukemia. The majority of patients were heavily pre-treated with greater than three re-induction chemotherapy regimens. Ten patients responded to T-EM treatment (59%). Four of seventeen (24%) had a complete remission and one had a partial remission. Four additional patients (24%) who scored complete leukemia clearance had no evidence of disease with complete white and red blood cell recovery but with platelet counts less than 100,000. The lack of platelet recovery in one patient having a partial response was scored as a partial leukemia clearance. The toxicity profile included major non-hematological toxicity including grade 3 mucositis (29%) and neutropenic fever (65%). Paired measurements of intracellular levels of topoisomerase II isoforms alpha and beta in leukemia blast cells (bone marrow) collected before (day 0) and after topotecan treatment (day 4) showed that a relative increase of topoisomerase IIalpha (Topo IIalpha) > or = 40% strongly correlated with response after T-EM treatment. Increased Topo IIalpha levels also corresponded to increased DNA fragmentation. Two patients who had an increase of Topo IIalpha of 20-25% had either a PR or PLC while patients with a < 10% increase showed no response to T-EM treatment. We conclude that timed sequential chemotherapy using topotecan followed by etoposide+mitoxantrone is an effective regimen for patients with refractory acute leukemia, and demonstrate Topo IIalpha protein level increases after topotecan treatment.

Long-term outcome in acute myelogenous leukemia autografted with mafosfamide-purged marrow in a single institution: adverse events and incidence of secondary myelodysplasia

We have analyzed the long-term outcome and toxicities in 98 patients with high-risk acute myelogenous leukemia (AML) who were treated with autologous bone marrow transplantation (ABMT) and monitored for a median observation period of 11.67 years. Between 1983 and 1994, 98 patients in our institution in first or second and higher complete remission (CR) underwent total body irradiation and high-dose cyclophosphamide prior to ABMT purged with mafosfamide. Twenty-seven out of the 90 evaluable patients (30%) were alive and in continuous CR for a median of 11.67 years (range, 6.39-15.53) after ABMT and could be considered as 'cured'. Among the 90 patients, 39 were transplanted at first CR and had a significantly higher survival rate than those transplanted at > or = 2 CR. Younger patients (<40 years) had a better prognosis and patients with FAB M1-4 had a more favorable outcome than those with M5. Long-term complications included four patients with cardiac complications, two with renal insufficiency. Five developed HCV infections, four myelodysplastic syndrome. The incidence of cataract among the long-term survivors was 44.4%. Therefore, a significant number of adult patients with AML in first CR derived long-term benefit from ABMT, despite the risks of a few long-term complications and of MDS (4.4%).

Combination chemotherapy of intermediate-dose cytarabine, idarubicin, plus etoposide and subsequent mobilized donor leukocyte infusion for relapsed acute leukemia after allogeneic bone marrow transplantation

The efficacy and side effects of intermediate-dose cytarabine, idarubicin plus etoposide and subsequent donor leukocyte infusion (DLI) were investigated in patients with acute leukemia who relapsed after allogeneic bone marrow transplantation (BMT). Patients were given cytarabine continuous i.v. (1 g/m2 per day x 5), idarubicin i.v. (12 mg/m2 per day x 3), and etoposide i.v. infusion (150 mg/m2 per day x 3). Two days later, G-CSF mobilized donor leukocytes were infused for 2 days. No graft-versus-host disease (GVHD) prophylaxis was given. Between August 1997 and February 2000, 13 patients enrolled (eight acute myeloid leukemia (AML) and five acute lymphoblastic leukemia (ALL)). All patients finished chemotherapy and DLI. Eleven patients (85%) achieved complete remission (CR) at median 27 days after DLI. After median follow up of 10.9 months (2.5-33.3), five of 11 patients who achieved CR relapsed. Overall, six of 13 patients were surviving (6/8 AML and 0/5 ALL, P=0.059). Marrow recovery after chemotherapy and DLI was rapid (12 days for absolute neutrophil count (ANC) >500/microl). Side effects included fever with neutropenia (100%), pneumonia (46%), grade II-IV mucositis (69%), grade III-IV acute GVHD (45%), and extensive chronic GVHD (64%). One patient died from chronic GVHD. Chemotherapy containing intermediate-dose cytarabine and DLI produced a high CR rate in acute leukemia in relapse after allogeneic BMT. A fraction of patients are surviving long term. Side effects were substantial but manageable.

Combination chemotherapy utilizing continuous infusion of intermediate-dose cytarabine for refractory or recurrent acute myeloid leukemia

Between October 1991 and December 1998, 19 patients (12 males and 7 females) with refractory (six patients) or recurrent (13 patients) AML were treated with a combination chemotherapy of cytarabine given by continuous infusion over 24-h at a rate of 1 upward arrow g/m2 per day for 5 days along with idarubicin (12 upward arrow mg/m2 per day x 3) and etoposide (150 mg /m(2) per day x 3). Median age of the patients was 28 years (range, 15--61). Seven (37%) of 19 patients achieved complete remission (CR) with median CR duration of 6.7 months (range, 2.5--61.4+). Two patients are surviving for long term (50.1 and 62.6 months). Myelosuppression associated with chemotherapy was severe. Median recovery time to ANC over 500/microl was 28 days (range, 25--59). A significant proportion of patients experienced grade III-VI non-hematologic toxicities including nausea/vomiting (32%), liver function abnormality (32%), and diarrhea (16%). No central nervous system (CNS) toxicity was observed. Our study showed that the administration of cytarabine at a dose of 1 g/m(2) per day by continuous intravenous infusion for 5 days along with idarubicin and etoposide was feasible. Further studies are necessary to elucidate optimum dose and schedule of cytarabine in a setting of refractory or relapsed acute myeloid leukemia (AML).

A phase I study of induction chemotherapy for older patients with newly diagnosed acute myeloid leukemia (AML) using mitoxantrone, etoposide, and the MDR modulator PSC 833: a southwest oncology group study 9617

Older patients with acute myelogenous leukemia (AML) have overexpression of P-glycoprotein (Pgp+), and this has been shown to correlate quantitatively with therapeutic outcome. Since Pgp-mediated efflux of cytotoxic drugs can be inhibited by the cyclosporine analogue, PSC 833, we investigated the use of this agent with a 5-day mitoxantrone/etoposide regimen in patients over age 55 with newly diagnosed AML. Previous studies suggested a 33% incidence of grade IV/V non-hematologic toxicity with the use of mitoxantrone 10 mg/M(2) and etoposide 100 mg/M(2), each for 5 days, in this patient population. Since PSC 833 alters the pharmacokinetic excretion of MDR-related cytotoxins, this phase I dose-finding study was performed to identify doses of mitoxantrone/etoposide associated with a similar 33% incidence of grade IV/V non-hematologic toxicity, when given with PSC 833. Mitoxantrone/etoposide (M/E) doses were escalated in fixed ratio from a starting dose of M: 4 mg/M(2) and E: 40 mg/M(2), to M: 7 mg/M(2) and E: 70 mg/M(2), in successive cohorts of eight patients each. PSC 833 was well tolerated and the MTD of this M/E regimen with PSC 833 in this population was M: 6 mg/M(2) and E: 60 mg/M(2). The complete response (CR) rate for all patients was 50% (15/30) and was considerably higher for de novo than for secondary AML. These data suggest that the addition of PSC 833 to an M/E regimen for older patients with untreated AML is well tolerated but requires a reduction in M/E dosing to avoid increased toxicity.