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

The Impact of Prophylactic Post-Chemotherapy G-CSF on the Relapse Rates in Patients with Acute Myeloid Leukemia: A Meta-Analysis

This meta-analysis evaluated the impact of prophylactic post-chemotherapy granulocyte colony-stimulating factor (G-CSF) in patients with acute myeloid leukemia (AML). Overall, the relapse rate, overall survival, event-free survival, and mortality rate were similar in G-CSF (+) compared to G-CSF (-) patients. However, the relative risk (RR) of relapse was higher in children and in secondary AML patients who were treated with G-CSF compared to the G-CSF (-) group [RR, 95% confidence interval: 1.26, 1.04-1.52, and 1.12 (1.02-1.24)]. Treatment with post-chemotherapy G-CSF should be prescribed with caution in pediatric patients with AML and secondary AML as possibly increasing the relapse risk.

Supportive care in pediatric acute myeloid leukemia:Expert-based recommendations of the NOPHO-DB-SHIP consortium

INTRODUCTION

Pediatric acute myeloid leukemia (AML) is the second most common type of pediatric leukemia. Patients with AML are at high risk for several complications such as infections, typhlitis, and acute and long-term cardiotoxicity. Despite this knowledge, there are no definite supportive care guidelines as to what the best approach is to manage or prevent these complications.

AREA COVERED

The NOPHO-DB-SHIP (Nordic-Dutch-Belgian-Spain-Hong-Kong-Israel-Portugal) consortium, in preparation for a new trial in pediatric AML patients, had dedicated meetings for supportive care. In this review, the authors discuss the available data and outline recommendations for the management of children and adolescents with AML with an emphasis on hyperleukocytosis, tumor lysis syndrome, coagulation abnormalities and bleeding, infection, typhlitis, malnutrition, cardiotoxicity, and fertility preservation.

EXPERT OPINION

Improved supportive care has significantly contributed to increased cure rates. Recommendations on supportive care are an essential part of treatment for this highly susceptible population and will further improve their outcome.

Neutropenia and Infection Prophylaxis in Childhood Cancer

PURPOSE OF REVIEW

Pediatric oncology patients frequently experience episodes of prolonged neutropenia which puts them at high risk for infection with significant morbidity and mortality. Here, we review the data on infection prophylaxis with a focus on both pharmacologic and ancillary interventions. This review does not include patients receiving hematopoietic stem cell transplantation.

RECENT FINDINGS

Patients with hematologic malignancies are at highest risk for infection. Bacterial and fungal prophylaxis decrease the risk of infection in certain high-risk groups. Ancillary measures such as ethanol locks, chlorhexidine gluconate baths, GCSF, IVIG, and mandatory hospitalization do not have enough data to support routine use. There is limited data on risk of infection and role of prophylaxis in patients receiving immunotherapy and patients with solid tumors. Patients with Down syndrome and adolescent and young adult patients may benefit from additional supportive care measures and protocol modifications. Consider utilizing bacterial and fungal prophylaxis in patients with acute myeloid leukemia or relapsed acute lymphoblastic leukemia. More research is needed to evaluate other supportive care measures and the role of prophylaxis in patients receiving immunotherapy.

Advances in acute myeloid leukemia

Acute myeloid leukemia (AML) is an uncommon but potentially catastrophic diagnosis with historically high mortality rates. The standard of care treatment remained unchanged for decades; however, recent discoveries of molecular drivers of leukemogenesis and disease progression have led to novel therapies for AML. Ongoing research and clinical trials are actively seeking to personalize therapy by identifying molecular targets, discovering patient specific and disease specific risk factors, and identifying effective combinations of modalities and drugs. This review focuses on important updates in diagnostic and disease classifications that reflect new understanding of the biology of AML, its mutational heterogeneity, some important genetic and environmental risk factors, and new treatment options including cytotoxic chemotherapy, novel targeted agents, and cellular therapies.

The safety profile of FLT3 inhibitors in the treatment of newly diagnosed or relapsed/refractory acute myeloid leukemia

INTRODUCTION

FLT3 inhibitors are important drugs in the therapy of FLT3 positive acute myeloid leukemia (AML). Midostaurin was registered in combination with chemotherapy to treat newly diagnosed AML. Gilteritinib and quizartinib demonstrate effectiveness in a randomized trial in relapsed/refractory AML. Several promising FLT3 inhibitors are being evaluated in clinical research.

AREAS COVERED

This review will report the safety of FLT3 inhibitors that are registered for acute myeloid leukemia induction and rescue therapy.

EXPERT OPINION

In the near future, it is possible that all the FLT3 positive non M3-AML patients will receive a FLT3 inhibitor. Therapy adherence and strategies to mitigate adverse events must be pursued. The treatment with FLT3 inhibitors may be optimized in terms of toxicities with a rational evaluation of antifungal prophylaxis and concomitant therapy, cardiology monitoring, and keeping in mind rare adverse events. Future studies on unfit patients, special populations, and maintenance settings are warranted, together with post-market studies and real-life experiences. Whenever new FLT3 inhibitors will come to the clinic, we could face a scenario in which profound knowledge of effectiveness, toxicities, and off-target effects will be relevant to choose the best drug for each patient.

Pharmacological prophylaxis of infection in pediatric acute myeloid leukemia patients

Introduction: Pediatric patients treated for acute myeloid leukemia (AML) are at high risk of developing severe infectious complications. The choice of an optimum supportive treatment should be based on local epidemiology, as well as intensity and toxicity of the anti-leukemic therapy applied.Areas covered: This review presents an overview of recently published studies focusing on the prevention of infection in pediatric AML patients. PubMed has been systematically searched for clinical trials, reviews, and meta-analyses published in the last 10 years. The focus of this article will be limited to primary prophylaxis only, while secondary prophylaxis is beyond the scope of the current review.Expert opinion: Although anti-bacterial agents may decrease the bacterial infection burden, there is no consensus regarding prophylactic use. To that end, there is a need for further randomized controlled trials to establish the precise role of anti-bacterial prophylaxis in pediatric AML patients. The prophylactic use of anti-fungal agents is strongly recommended for all AML patients. Since the contribution of hematopoietic growth factors to improved survival has not been demonstrated, they should not be routinely applied. Decisions regarding an appropriate prophylactic strategy should be taken in collaboration with the infectious disease experts and pharmacology team.

Strategies to generate functionally normal neutrophils to reduce infection and infection-related mortality in cancer chemotherapy

Neutrophils form an essential part of innate immunity against infection. Cancer chemotherapy-induced neutropenia (CCIN) is a condition in which the number of neutrophils in a patient's bloodstream is decreased, leading to increased susceptibility to infection. Granulocyte colony-stimulating factor (GCSF) has been the only approved treatment for CCIN over two decades. To date, CCIN-related infection and mortality remain a significant concern, as neutrophils generated in response to administered GCSF are functionally immature and cannot effectively fight infection. This review summarizes the molecular regulatory mechanisms of neutrophil granulocytic differentiation and innate immunity development, dissects the biology of GCSF in myeloid expansion, highlights the shortcomings of GCSF in CCIN treatment, updates the recent advance of a selective retinoid agonist that promotes neutrophil granulocytic differentiation, and evaluates the benefits of developing GCSF biosimilars to increase access to GCSF biologics versus seeking a new mode to fundamentally advance GCSF therapy for treatment of CCIN.

A CD123-targeting antibody-drug conjugate, IMGN632, designed to eradicate AML while sparing normal bone marrow cells

The outlook for patients with refractory/relapsed acute myeloid leukemia (AML) remains poor, with conventional chemotherapeutic treatments often associated with unacceptable toxicities, including severe infections due to profound myelosuppression. Thus there exists an urgent need for more effective agents to treat AML that confer high therapeutic indices and favorable tolerability profiles. Because of its high expression on leukemic blast and stem cells compared with normal hematopoietic stem cells and progenitors, CD123 has emerged as a rational candidate for molecularly targeted therapeutic approaches in this disease. Here we describe the development and preclinical characterization of a CD123-targeting antibody-drug conjugate (ADC), IMGN632, that comprises a novel humanized anti-CD123 antibody G4723A linked to a recently reported DNA mono-alkylating payload of the indolinobenzodiazepine pseudodimer (IGN) class of cytotoxic compounds. The activity of IMGN632 was compared with X-ADC, the ADC utilizing the G4723A antibody linked to a DNA crosslinking IGN payload. With low picomolar potency, both ADCs reduced viability in AML cell lines and patient-derived samples in culture, irrespective of their multidrug resistance or disease status. However, X-ADC exposure was >40-fold more cytotoxic to the normal myeloid progenitors than IMGN632. Of particular note, IMGN632 demonstrated potent activity in all AML samples at concentrations well below levels that impacted normal bone marrow progenitors, suggesting the potential for efficacy in AML patients in the absence of or with limited myelosuppression. Furthermore, IMGN632 demonstrated robust antitumor efficacy in multiple AML xenograft models. Overall, these findings identify IMGN632 as a promising candidate for evaluation as a novel therapy in AML.

A phase I study of selinexor in combination with high-dose cytarabine and mitoxantrone for remission induction in patients with acute myeloid leukemia

BACKGROUND

Novel therapies for patients with acute myeloid leukemia (AML) are imperative, particularly for those with high-risk features. Selinexor, an exportin 1 (XPO1/CRM1) inhibitor, has demonstrated anti-leukemia activity as a single agent, as well as in combination with anthracyclines and/or DNA-damaging agents.

METHODS

We report the findings of a phase I dose escalation trial with cohort expansion in 20 patients with newly diagnosed or relapsed/refractory AML that combined selinexor with age-adjusted high-dose cytarabine and mitoxantrone (HiDAC/Mito).

RESULTS

Three (15%) patients received the initial dose of 60 mg of selinexor (~ 35 mg/m2), and 17 (85%) received the target level of 80 mg (~ 50 mg/m2). No dose-limiting toxicities were observed. Common adverse events included febrile neutropenia (70%), diarrhea (40%), anorexia (30%), electrolyte abnormalities (30%), bacteremia (25%), cardiac toxicities (25%), fatigue (25%), and nausea/vomiting (25%). None were unexpected given the HiDAC/Mito regimen. Serious adverse events occurred in 6 (30%) patients; one was fatal. Ten (50%) patients achieved a complete remission (CR), 3 (15%) achieved CR with incomplete recovery (CRi), 1 (5%) achieved partial remission (PR), and 6 (30%) had progressive disease for an overall response rate (ORR) of 70%. Eight of 14 (57%) responders proceeded to allogeneic stem cell transplantation. Correlative studies of WT1 levels showed persistently detectable levels in patients who either did not respond or relapsed quickly after induction.

CONCLUSION

The selinexor/HiDAC/Mito regimen is feasible and tolerable at selinexor doses of 80 mg/day (~ 50 mg/m2/day) twice weekly. The recommended phase II dose is 80 mg and warrants further study in this combination.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02573363 . Registered October 5, 2015.

Condensed versus standard schedule of high-dose cytarabine consolidation therapy with pegfilgrastim growth factor support in acute myeloid leukemia

The aim of this cohort study was to compare a condensed schedule of consolidation therapy with high-dose cytarabine on days 1, 2 and 3 (HDAC-123) with the HDAC schedule given on days 1, 3 and 5 (HDAC-135) as well as to evaluate the prophylactic use of pegfilgrastim after chemotherapy in younger patients with acute myeloid leukemia in first complete remission. One hundred and seventy-six patients were treated with HDAC-135 and 392 patients with HDAC-123 with prophylactic pegfilgrastim at days 10 and 8, respectively, in the AMLSG 07-04 and the German AML Intergroup protocol. Time from start to chemotherapy until hematologic recovery with white blood cells >1.0 G/l and neutrophils >0.5 G/l was in median 4 days shorter in patients receiving HDAC-123 compared with HDAC-135 (P<0.0001, each), and further reduced by 2 days (P<0.0001) by pegfilgrastim. Rates of infections were reduced by HDAC-123 (P<0.0001) and pegfilgrastim (P=0.002). Days in hospital and platelet transfusions were significantly reduced by HDAC-123 compared with HDAC-135. Survival was neither affected by HDAC-123 versus HDAC-135 nor by pegfilgrastim. In conclusion, consolidation therapy with HDAC-123 leads to faster hematologic recovery and less infections, platelet transfusions as well as days in hospital without affecting survival.

Novel strategies for improving hematopoietic reconstruction after allogeneic hematopoietic stem cell transplantation or intensive chemotherapy

INTRODUCTION

High-dose conditioning regimens for allogeneic hematopoietic cell transplantation (allo-HCT) as well as intensive poly-chemotherapy for acute myeloid leukemia (AML) induce prolonged periods of neutropenia. The duration of the neutropenia is particularly long following umbilical cord blood transplantation (UCBT). Areas covered: After briefly reviewing the impact of hematopoietic growth factors administration to hasten hematologic reconstitution after allo-HCT or intensive AML chemotherapy, this article summarizes recent approaches that have been investigated to prompt hematologic reconstruction after UCBT or intensive AML chemotherapy. Expert opinion: In the allo-HCT setting, administration of G-CSF or GM-CSF shortened the duration of the neutropenia but failed to decrease infection-related mortality or to improve survival. Novel approaches to hasten hematological reconstruction after UCBT such as double UCBT with expansion of one of the 2 UCB units with Notch ligand, mesenchymal stromal cells, nicotinamide, or StemRegenin 1, co-transplanting a single UCB unit with HLA-haploidentical CD34+ cells, or increasing UCB HSC homing to marrow niches via direct intra bone UCB administration, pulse treatment with dmPGE2 or enforced fucosylation are promising and deserve further investigations in prospective phase III studies. In the AML setting, G-CSF or GM-CSF administration after intensive chemotherapy decreased the duration of the neutropenia without improving survival.

Am80-GCSF synergizes myeloid expansion and differentiation to generate functional neutrophils that reduce neutropenia-associated infection and mortality

Neutrophils generated by granulocyte colony‐stimulating factor (GCSF) are functionally immature and, consequently, cannot effectively reduce infection and infection‐related mortality in cancer chemotherapy‐induced neutropenia (CCIN). Am80, a retinoic acid (RA) agonist that enhances granulocytic differentiation by selectively activating transcription factor RA receptor alpha (RARα), alternatively promotes RA‐target gene expression. We found that in normal and malignant primary human hematopoietic specimens, Am80‐GCSF combination coordinated proliferation with differentiation to develop complement receptor‐3 (CR3)‐dependent neutrophil innate immunity, through altering transcription of RA‐target genes RARβ_2,C/EBPε, CD66,CD11b, and CD18. This led to generation of functional neutrophils capable of fighting infection, whereas neutralizing neutrophil innate immunity with anti‐CD18 antibody abolished neutrophil bactericidal activities induced by Am80‐GCSF. Further, Am80‐GCSF synergy was evaluated using six different dose‐schedule‐infection mouse CCIN models. The data demonstrated that during “emergency” granulopoiesis in CCIN mice undergoing transient systemic intravenous bacterial infection, Am80 effect on differentiating granulocytic precursors synergized with GCSF‐dependent myeloid expansion, resulting in large amounts of functional neutrophils that reduced infection. Importantly, extensive survival tests covering a full cycle of mouse CCIN with perpetual systemic intravenous bacterial infection proved that without causing myeloid overexpansion, Am80‐GCSF generated sufficient numbers of functional neutrophils that significantly reduced infection‐related mortality in CCIN mice. These findings reveal a differential mechanism for generating functional neutrophils to reduce CCIN‐associated infection and mortality, providing a rationale for future therapeutic approaches.

Pharmacodynamics of cytarabine induced leucopenia: a retrospective cohort study

AIMS

Cytarabine is a pyrimidine analogue used to treat a variety of haematological malignancies. There are few data regarding the pharmacodynamics of cytarabine. The only publications regarding this issue cite a biphasic pattern of decline in white blood cell (WBC) counts following low and intermediate doses, in patients with various malignancies, most of them non-haematological. Our purpose was to establish the pharmacodynamics of cytarabine induced leucopenia in acute myeloid leukaemia (AML) patients treated with contemporary cytarabine containing protocols.

METHODS

We conducted a retrospective cohort study, including 56 patients with AML in complete remission who had received 89 cycles of intermediate or high dose cytarabine. Daily counts for WBCs and neutrophils (ANC) were collected during the first 15 days after the initiation of cytarabine administration and pharmacodynamics were analyzed. Further analysis was carried out to correlate between WBC and ANC pharmacodynamics and different cytarabine protocols [high dose cytarabine (HiDAC) vs. intermediate dose cytarabine (IDAC)].

RESULTS

Analysis of blood counts demonstrated a monophasic decline of WBCs and ANCs, unlike a previous depiction of a biphasic pattern. HiDAC was associated with a significantly sharper decline of WBCs than IDAC.

CONCLUSIONS

Our data support a monophasic decline pattern of WBCs and ANCs following contemporary cytarabine protocols. The decline rate is steeper for patients receiving HiDAC than for those receiving IDAC. These results might help form evidence based guidelines regarding patient monitoring intensity, timing of prophylactic antibacterial and antifungal treatment as well as growth factors' support following cytarabine based consolidation for AML.

Prediction of adverse events during intensive induction chemotherapy for acute myeloid leukemia or high-grade myelodysplastic syndromes

Intensive chemotherapy for newly diagnosed acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) is associated with significant treatment-related morbidity and mortality. Herein, we investigate how pretreatment characteristics relate to early adverse outcomes in such patients, studying 205 consecutive individuals receiving curative-intent induction chemotherapy with cytarabine and an anthracycline ("7 + 3"; n = 175) or a "7 + 3"-like regimen (n = 30). Among the entire cohort, baseline grade 4 neutropenia (i.e., absolute neutrophil count <500 cells/µL) was associated with development of fever (P = 0.04), documented infection (P < 0.0001), and bacteremia (P = 0.002) but not requirement for intensive care unit-level care; after exclusion of the 30 patients who received "7 + 3"-like induction, baseline grade 4 neutropenia remained associated with documented infection (P < 0.0001) and bacteremia (P = 0.0005). Among patients achieving a complete remission with the initial treatment cycle, grade 4 neutropenia was associated with delayed neutrophil count recovery (P < 0.0001). Low monocyte and lymphocyte counts at baseline were similarly associated with increased risk of documented infection or bacteremia. After adjustment for age, gender, disease type, cytogenetic/molecular risk, and performance status, the risk of fever, documented infection, or bacteremia was 1.87 (95% confidence interval: 1.04-3.34; P=0.04)-fold, 4.95 (2.20-11.16; P<0.001)-fold, and 3.14 (0.99-9.98; P=0.05)-fold higher in patients with initial grade 4 neutropenia. Together, our studies identify severe baseline neutropenia as a risk factor for infection-associated adverse events after induction chemotherapy and may provide the rationale for the risk-adapted testing of myeloid growth factor support in this high-risk AML/MDS patient subset.

Effectiveness of supportive care measures to reduce infections in pediatric AML: a report from the Children's Oncology Group

Objective was to describe the effect of antibiotic and granulocyte colony-stimulating factor (G-CSF) prophylaxis and discharge policy on infection risk and nonrelapse-related mortality (NRM) during chemotherapy for children with acute myeloid leukemia. Patients were non-Down syndrome children enrolled on Children's Oncology Group (COG) trial AAML0531. We surveyed sites to determine institutional standards for systemic antibacterial, antifungal, and G-CSF prophylaxis, and mandatory hospitalization during neutropenia. COG institution survey response rate was 180 of 216 (83.3%). Of 1024 patients enrolled on AAML0531, 897 were non-Down patients from survey-responding institutions. In multiple regression, antibacterial prophylaxis reduced any sterile-site bacterial infection (incidence rate ratio [IRR] 0.85; 95% confidence interval [CI], 0.72-1.01; P = .058) and Gram-positive sterile-site infection (IRR 0.71; 95% CI, 0.57-0.90; P = .004). Prophylactic G-CSF reduced bacterial (IRR 0.79; 95% CI, 0.67-0.92; P = .004) and Clostridium difficile infections (CDIs; IRR 0.46; 95% CI, 0.25-0.84; P = .012). Mandatory hospitalization did not reduce bacterial/fungal infection or significantly reduce NRM but did increase CDI (IRR 1.96; 95% CI, 1.34-2.87; P < .001). Antibacterial and G-CSF prophylaxis reduced infection rates while mandatory hospitalization did not reduce infection or significantly affect NRM. This trial was registered at www.clinicaltrials.gov as #AAML0531.

Retinoid agonist Am80-enhanced neutrophil bactericidal activity arising from granulopoiesis in vitro and in a neutropenic mouse model

Despite advances in the therapeutic use of recombinant granulocyte colony-stimulating factor (G-CSF) to promote granulopoiesis of human hematopoietic stem cells (HSCs), neutropenia remains one of the most serious complications of cancer chemotherapy. We discovered that retinoid agonist Am80 (tamibarotene) is more potent than G-CSF in coordinating neutrophil differentiation and immunity development. Am80-induced neutrophils (AINs) either in vitro or in neutropenic mouse model displayed strong bactericidal activities, similar to those of human peripheral blood neutrophils (PBNs) or mouse peripheral blood neutrophils (MPBNs) but markedly greater than did G-CSF–induced neutrophils (GINs). In contrast to GINs but similar to PBNs, the enhanced bacterial killing by AINs accompanied both better granule maturation and greater coexpression of CD66 antigen with the integrin β2 subunit CD18. Consistently, anti-CD18 antibody neutralized Am80-induced bactericidal activities of AINs. These studies demonstrate that Am80 is more effective than G-CSF in promoting neutrophil differentiation and bactericidal activities, probably through coordinating the functional interaction of CD66 with CD18 to enhance the development of neutrophil immunity during granulopoiesis. Our findings herein suggest a molecular rationale for developing new therapy against neutropenia using Am80 as a cost-effective treatment option.