Colony-stimulating factor-1 receptor inhibition attenuates microgliosis and myelin loss but exacerbates neurodegeneration in the chronic cuprizone model

Multiple sclerosis (MS), especially in its progressive phase, involves early axonal and neuronal damage resulting from a combination of inflammatory mediators, demyelination, and loss of trophic support. During progressive disease stages, a microenvironment is created within the central nervous system (CNS) favoring the arrival and retention of inflammatory cells. Active demyelination and neurodegeneration have also been linked to microglia (MG) and astrocyte (AST)-activation in early lesions. While reactive MG can damage tissue, exacerbate deleterious effects, and contribute to neurodegeneration, it should be noted that activated MG possess neuroprotective functions as well, including debris phagocytosis and growth factor secretion. The progressive form of MS can be modelled by the prolonged administration to cuprizone (CPZ) in adult mice, as CPZ induces highly reproducible demyelination of different brain regions through oligodendrocyte (OLG) apoptosis, accompanied by MG and AST activation and axonal damage. Therefore, our goal was to evaluate the effects of a reduction in microglial activation through orally administered brain-penetrant colony-stimulating factor-1 receptor (CSF-1R) inhibitor BLZ945 (BLZ) on neurodegeneration and its correlation with demyelination, astroglial activation and behavior in a chronic CPZ-induced demyelination model. Our results show that BLZ treatment successfully reduced the microglial population and myelin loss. However, no correlation was found between myelin preservation and neurodegeneration, as axonal degeneration was more prominent upon BLZ treatment. Concomitantly, BLZ failed to significantly offset CPZ-induced astroglial activation and behavioral alterations. These results should be taken into account when proposing the modulation of microglial activation in the design of therapies relevant for demyelinating diseases.

Colony stimulating factors (including erythropoietin, granulocyte colony stimulating factor and analogues) for stroke

BACKGROUND

Colony stimulating factors (CSFs), also called haematopoietic growth factors, regulate bone marrow production of circulating red and white cells, and platelets. Some CSFs also mobilise the release of bone marrow stem cells into the circulation. CSFs have been shown to be neuroprotective in experimental stroke.

OBJECTIVES

To assess (1) the safety and efficacy of CSFs in people with acute or subacute ischaemic or haemorrhagic stroke, and (2) the effect of CSFs on circulating stem and blood cell counts.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched September 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 4), MEDLINE (1985 to September 2012), EMBASE (1985 to September 2012) and Science Citation Index (1985 to September 2012). In an attempt to identify further published, unpublished and ongoing trials we contacted manufacturers and principal investigators of trials (last contacted April 2012). We also searched reference lists of relevant articles and reviews.

SELECTION CRITERIA

We included randomised controlled trials recruiting people with acute or subacute ischaemic or haemorrhagic stroke. CSFs included stem cell factor (SCF), erythropoietin (EPO), granulocyte colony stimulating factor (G-CSF), granulocyte-macrophage colony stimulating factor (GM-CSF), macrophage-colony stimulating factor (M-CSF, CSF-1), thrombopoietin (TPO), or analogues of these. The primary outcome was functional outcome at the end of the trial. Secondary outcomes included safety at the end of treatment, death at the end of follow-up, infarct volume and haematology measures.

DATA COLLECTION AND ANALYSIS

Two review authors (TE and NS) independently extracted data and assessed trial quality. We contacted study authors for additional information.

MAIN RESULTS

We included a total of 11 studies involving 1275 participants. In three trials (n = 782), EPO therapy was associated with a significant increase in death by the end of the trial (odds ratio (OR) 1.98, 95% confidence interval (CI) 1.19 to 3.3, P = 0.009) and a non-significant increase in serious adverse events. EPO significantly increased the red cell count with no effect on platelet or white cell count, or infarct volume. Two small trials of carbamylated EPO have been completed but have yet to be reported. We included eight small trials (n = 548) of G-CSF. G-CSF was associated with a non-significant reduction in early impairment (mean difference (MD) -0.4, 95% CI -1.82 to 1.01, P = 0.58) but had no effect on functional outcome at the end of the trial. G-CSF significantly elevated the white cell count and the CD34+ cell count, but had no effect on infarct volume. Further trials of G-CSF are ongoing.

AUTHORS' CONCLUSIONS

There are significant safety concerns regarding EPO therapy for stroke. It is too early to know whether other CSFs improve functional outcome.

Comparative effectiveness of colony-stimulating factors for febrile neutropenia: a retrospective study

BACKGROUND

Granulocyte colony stimulating factors (G-CSFs) decrease the incidence of febrile neutropenia (FN) in cancer patients receiving myelosuppressive chemotherapy. There are two G-CSFs (pegfilgrastim and filgrastim) that differ in dosing schedules from which oncologists may prescribe.

OBJECTIVES

This study aimed to compare the effectiveness of prophylactic pegfilgrastim and filgrastim on the risk of hospitalizations. The secondary objective was to compare the effectiveness of the timing of initiation (prophylactic versus delayed).

METHODS

A retrospective study of administrative claims from US commercial payers included adult patients with Non-Hodgkin's lymphoma, breast, or lung cancer, treated with chemotherapy between July 2004 and January 2008. For these patients, the first course of chemotherapy and each unique cycle with use of G-CSF was identified and designated 'prophylaxis' if used within the first 5 days of each cycle, or 'delayed', if after day 5. The risk of neutropenia-related and all-cause hospitalization was evaluated for the pegfilgrastim and filgrastim prophylaxis cohorts and for the prophylaxis and delayed G-CSF initiation cohorts.

RESULTS

Among 5,571 patient-cycles identified, 88.9% and 11.1% used pegfilgrastim and filgrastim respectively. The rate of neutropenic hospitalization was 1.1% for pegfilgrastim prophylaxis and 3.5% for filgrastim prophylaxis (P = 0.001). Compared to chemotherapy cycles with filgrastim prophylaxis, those with pegfilgrastim prophylaxis had decreased risk of neutropenia-related (adjusted odds ratio (OR) = 0.38, 95% confidence interval (CI) 0.17-0.83) and all-cause hospitalization (adjusted OR = 0.51, 95% CI 0.31-0.84). The neutropenic hospitalization rate was 1.2% for G-CSF prophylactic initiation and 3.7% for delayed G-CSF initiation (P < 0.001). Chemotherapy cycles with prophylactic initiation of either G-CSF had decreased risk of neutropenia-related (adjusted OR = 0.34, 95% CI 0.21-0.56) and all-cause hospitalization (adjusted OR = 0.67, 95% CI 0.49-0.91) compared with delayed initiation of G-CSF.

CONCLUSIONS

Pegfilgrastim prescribed as prophylaxis resulted in lower risk of neutropenia-related and all-cause hospitalizations compared to filgrastim prophylaxis. This reduction was similar for prophylactic G-CSF initiation when compared to delayed G-CSF initiation.

Use of Colony-Stimulating Factors for Chemotherapy-Associated Neutropenia: Review of Current Guidelines

Chemotherapy-associated neutropenia is often dose-limiting and may compromise treatment efficacy. Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage-colony-stimulating factor (GM-CSF) are increasingly used to prevent febrile neutropenia (FN) or to increase dose-density. This review discusses recent changes in treatment guidelines for chemotherapy-associated neutropenia. Primary prophylactic use of CSFs is now recommended as a treatment option at an overall risk of FN of 20%, not taking into account cost-effectiveness. To estimate the risk of FN, patient-, disease-, and treatment-related factors predicting an adverse outcome of FN have been determined. Dose-dense chemotherapy has become feasible with the use of CSFs. However, clinical benefit has been shown only for specific chemotherapy regimens in breast cancer, small cell lung cancer (SCLC), and non-Hodgkin's lymphoma (NHL), for the latter particularly for patients above 60 years of age. Strategies are being developed to tailor the use of CSFs to patients with a high risk of adverse outcome of FN.

Role of colony stimulating factors (CSFs) in solid tumours: Results of an expert panel

Febrile neutropenia is a relatively frequent event in cancer patients treated with chemotherapy. A relevant body of scientific evidence has been produced in the last 2 decades, through clinical trials addressing the efficacy of colony stimulating factors (CSFs) in the prevention and treatment of febrile neutropenia. The correct use of CSFs needs to be optimized, and several guidelines have been produced and periodically updated, in order to uniform and guide clinical practice. The aim of this review is to synthesize the most relevant clinical trials and the most important existing guidelines about the role of CSFs in solid tumours. Role of CSFs as primary prophylaxis, secondary prophylaxis and treatment of afebrile and febrile neutropenia is discussed. A special focus is dedicated to neutropenia and the use of CSFs in the treatment of the three "big killers" among the solid tumours: breast cancer, lung cancer and colorectal cancer.

An open-label study of darbepoetin alfa administered once monthly for the maintenance of haemoglobin concentrations in patients with chronic kidney disease not receiving dialysis

OBJECTIVE

To demonstrate the efficacy and safety of once-monthly (QM) darbepoetin alfa administration in maintaining haemoglobin (Hb) 11.0-13.0 g dL(-1) in subjects with chronic kidney disease (CKD) not receiving dialysis and previously treated with darbepoetin alfa every other week (Q2W).

SUBJECTS

This open-label study enrolled subjects > or =18 years of age who had glomerular filtration rate > or =15 and < or =60 mL min(-1)/1.73 m(2), had Hb 11.0-13.0 g dL(-1), and were receiving Q2W darbepoetin alfa.

DESIGN

Subjects were switched to QM darbepoetin alfa therapy for 28 weeks; the QM dose was titrated to maintain Hb levels. Primary end-point: proportion of subjects maintaining Hb > or =11.0 g dL(-1) during the final 8 weeks of the study (evaluation phase). Secondary end-points: Hb concentration during evaluation, darbepoetin alfa dose during the study, adverse events, laboratory parameters, and blood pressure.

RESULTS

The study enrolled 152 subjects (female 52%, white 64%). Mean Hb > or =11.0 g dL(-1) during evaluation was achieved by 76% of the 150 subjects who received at least one dose of darbepoetin alfa [95% confidence interval (CI): 68%, 83%]. Mean (SD) Hb during evaluation was 11.71 (0.92) g dL(-1). Eighty-five per cent of 129 subjects who completed the study (95% CI: 78%, 91%) had Hb > or =11.0 g dL(-1) during evaluation. The dose of darbepoetin alfa over the study period was median (95% CI) 124.4 mug (106.2, 140.0). Darbepoetin alpha administered QM was well tolerated in study subjects.

CONCLUSION

Darbepoetin alpha administered QM maintained Hb in study subjects with CKD not receiving dialysis.

Hematopoietic Colony Stimulating Factors in Cardiovascular and Pulmonary Remodeling: Promoters or Inhibitors?

Hemopoietic colony stimulating factors (HCSFs) are naturally occurred substances that are released in response to infection or inflammation and regulate the proliferation and differentiation of hemopoietic progenitor cells. Some representative members of this peptide family induce atherogenesis through the mediation of monocyte-endothelial cell adhesive interaction and promotion of angiogenesis within the atherosclerotic plaques. HCSFs, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), also promote post-infarction cardiac remodeling though the enhanced activation and infiltration of monocytes into injured myocardial tissue and through altered equilibrium of collagen deposition/degradation. On the other hand, exogenous administration of granulocyte colony-stimulating factor (G-CSF) or eythropoietin (EPO) in patients with chronic ischemic disease or recent myocardial infarction have lead to beneficial arteriogenesis or myocardial cell regeneration, thus preventing adverse cardiac remodeling. While GM-CSF may hold therapeutic potential as an inhibitor of lung fibrogenesis, G-CSF appears to promote fibrosis in the lungs. The pathophysiological role of HCSFs also depends on the timing of their action on cardiovascular remodeling, as well as on the target progenitor hematopoietic cell. This article summarizes current knowledge about the clinical and therapeutic implications of these factors in chronic artery disease, post-infarction cardiac remodeling, chronic heart failure and in pulmonary fibrosis.

2006 update of recommendations for the use of white blood cell growth factors: an evidence-based clinical practice guideline

PURPOSE

To update the 2000 American Society of Clinical Oncology guideline on the use of hematopoietic colony-stimulating factors (CSF).

UPDATE METHODOLOGY

The Update Committee completed a review and analysis of pertinent data published from 1999 through September 2005. Guided by the 1996 ASCO clinical outcomes criteria, the Update Committee formulated recommendations based on improvements in survival, quality of life, toxicity reduction and cost-effectiveness.

RECOMMENDATIONS

The 2005 Update Committee agreed unanimously that reduction in febrile neutropenia (FN) is an important clinical outcome that justifies the use of CSFs, regardless of impact on other factors, when the risk of FN is approximately 20% and no other equally effective regimen that does not require CSFs is available. Primary prophylaxis is recommended for the prevention of FN in patients who are at high risk based on age, medical history, disease characteristics, and myelotoxicity of the chemotherapy regimen. CSF use allows a modest to moderate increase in dose-density and/or dose-intensity of chemotherapy regimens. Dose-dense regimens should only be used within an appropriately designed clinical trial or if supported by convincing efficacy data. Prophylactic CSF for patients with diffuse aggressive lymphoma aged 65 years and older treated with curative chemotherapy (CHOP or more aggressive regimens) should be given to reduce the incidence of FN and infections. Current recommendations for the management of patients exposed to lethal doses of total body radiotherapy, but not doses high enough to lead to certain death due to injury to other organs, includes the prompt administration of CSF or pegylated G-CSF.

Trends in the Use of Colony-stimulating Factors

Colony-stimulating factors are potent manipulators of the hematopoietic and immune systems. An increasing number of colony-stimulating factors with expanded indications and uses are available. To provide safe and efficacious therapy, clinicians must understand how colony-stimulating factors and other biologic response modifiers work and know about product use, patient education, and patient monitoring. This article provides an overview of the current colony-stimulating factor products, uses, indications, administration, management, and patient education.

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.

An experimental ointment formulation of pimecrolimus is effective in psoriasis without occlusion

Pimecrolimus (Elidel, SDZ ASM 981), a new macrolactam ascomycin derivative, was highly effective in treating plaque-type psoriasis when applied under Finn-chamber occlusion. A two-centre, randomized, double-blind, vehicle- and positive-controlled within-patient study was therefore conducted in 23 adult psoriasis patients. Pimecrolimus 1% was applied, twice daily, in an experimental ointment formulation, along with the corresponding vehicle, 0.005% calcipotriol ointment and 0.05% clobetasol-17-propionate ointment to test sites without occlusion for 21 days. Erythema, induration and scaling (score: 0 [absent] to 4 [severe]) were evaluated. The total sign score was defined as the sum of the erythema, induration and scaling scores (range 0-12). Pimecrolimus 1% ointment was significantly (p = 0.03) more effective than the corresponding vehicle, with an improvement in total sign score of 51.4% compared with 36.7% for the corresponding vehicle. Improvements with calcipotriol and clobetasol-17-propionate were 71.5% and 88.3%, respectively. No local or systemic drug-related side effects were observed in the study. We conclude that pimecrolimus 1% in the experimental ointment formulation was significantly more effective than its corresponding vehicle, but less effective than calcipotriol and clobetasol ointment. This is the first study reporting a significant therapeutic effect of pimecrolimus in an ointment formulation applied without occlusion to psoriatic plaques.

Adult purpura fulminans associated with staphylococcal infection and administration of colony-stimulating factors

Purpura fulminans (PF) is a rare syndrome of progressive haemorragic necrosis due to disseminated intravascular coagulation (DIC) and dermal vascular thrombosis leading to purpura and tissue necrosis. PF is more often associated with either a benign infection or a severe sepsis. Rarely, it has been related to drug intake. We report the case of a 24-year-old female patient who suffered from staphylococcal sepsis and pancytopenia, for which she was treated with antibiotics, granulocyte-colony stimulating factor (G-CSF) and granulocyte/macrophage CSF (GM-CSF). Two days after the last GM-CSF dose, she developed widespread necrotic plaques with erythematous borders and purpura in the breast, arms and legs. Coagulation tests indicated DIC and a skin biopsy showed fibrin thrombi in the superficial dermal vessels. The patient totally recovered after removal of the necrotic tissues and application of skin autografts. Although staphylococcal infection was most probably involved in the development of PF, a role of CSF cannot be excluded in this case.

[Blood doping and cardiovascular consequences]

THE REASONS FOR BLOOD DOPING: The aim of doping the hematological functions is to increase the quantity of oxygen supplied to the muscles in activity. THE DOPING METHODS: Self blood transfusion was one of the first methods used. The incriminated substances are blood substitutes, non-specific and specific hematopoietic growth factors such as erythropoietin and granulocyte macrophage colony stimulating factor, and other substances such as perfluorocarbon and RSR13. DELETERIOUS CONSEQUENCES: The major risk is that of a hyperviscosity syndrome, responsible for thrombosis and decreased cardiac output.

IN PRACTICE

All physicians are concerned, since they may be confronted with the complications of doping in their daily practice. They should also know the list of prohibited substances, in order to avoid any errors in prescription.

New treatment options for managing chemotherapy-induced neutropenia

New treatment options for managing chemotherapy-induced neutropenia are reviewed. The benefits of using colony-stimulating factors in cancer patients are evolving and include preventing neutropenia and decreasing its severity and duration. However, several areas of controversy regarding chemotherapy-induced neutropenia and the use of colony-stimulating factors remain: dose intensity, which colony-stimulating factor to use and when, and administration. Colony-stimulating factors have not been found to increase overall survival time in patients undergoing chemotherapy, but they are used to prevent febrile neutropenia, reduce hospitalizations, and improve quality of life. The methods of using colony-stimulating factors are also evolving, with altered administration showing potential as a means of reducing treatment cost. If the rate of febrile neutropenia for a given combination chemotherapy regimen is < 40%, routine prophylactic use of colony-stimulating factors is not considered cost-effective and is not recommended by the American Society of Clinical Oncology. Pegfilgrastim is filgrastim to which polyethylene glycol has been added to extend the drug's half-life and permit less frequent administration. The issue of dose intensity will continue to be evaluated as new cytotoxic agents and combinations are introduced. Better models for identifying patients most likely to benefit from colony-stimulating factors are needed.

Haemopoietic growth factors in paediatric oncology: a review of the literature

Recombinant haemopoietic growth factors (HGFs) are an attractive adjunct to reduce morbidity from chemotherapy regimens and their use has become widespread in paediatric oncology. Although patients receiving HGFs often have faster haematological recovery after intensive chemotherapy, this does not always translate into meaningful clinical benefits. This article reviews the clinical effectiveness of HGFs in a variety of different contexts. Most published studies have used granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) as prophylaxis to ameliorate the subsequent neutropenia following intensive chemotherapy. These 2 agents have also been used to mobilise peripheral blood stem cells for autologous transplantation. HGFs specific for anaemia and thrombocytopenia are currently in paediatric clinical trials and it is hoped that the proper context and administration strategy can be found to make their use clinically effective. This article also reviews data on toxicity, specifically focusing on differences between various formulations of growth factors. HGFs are expensive, and cost-benefit analyses reviewed in this article give an important perspective on the financial aspects of paediatric cancer care. Because HGFs do not benefit every child receiving chemotherapy and overuse increases costs and may result in unnecessary adverse effects, evidence-based guidelines for their rational use in paediatric oncology are proposed.

Tolerability and side-effect profile of rhIL-11

Safety data from two randomized phase II and one abbreviated phase III placebo-controlled, double-blind clinical studies in adult patients with nonmyeloid malignancies indicate that recombinant human interleukin-11 (rhIL-11, also known as oprelvekin [Neumega]) has an acceptable toxicity profile as therapy for the mitigation of chemotherapy-induced thrombocytopenia. Preliminary data also indicate that rhIL-11 is well tolerated by pediatric patients with similar types of cancers. Adverse events associated with rhIL-11 are generally mild or moderate, reversible with drug discontinuation, and easily managed. Many of the common adverse events of rhIL-11--including edema, dyspnea, pleural effusions, conjunctival injection, and in some patients, atrial arrhythmia--occur in association with fluid retention. However, these adverse events can be medically managed and need not limit the use of rhIL-11, particularly if ameliorative measures, such as salt restriction and occasional prophylaxis with a potassium-sparing diuretic to minimize peripheral edema, have been instituted along with close monitoring of fluid and electrolyte status. Such measures are suggested for any patient treated with a diuretic, especially patients with cancer who are receiving multiple medications that complicate overall care. Administration of sequential cycles of rhIL-11 treatment does not appear to result in an increased incidence of adverse events or bone marrow exhaustion. rhIL-11 does not appear to interact adversely with concomitantly administered chemotherapeutic agents or agents commonly used for supportive care, including granulocyte colony-stimulating factor (G-CSF, filgrastim [Neu-pogen]).

[Novel ways of using hemopoietic growth factors]

The myelopoietic growth factors, in particular G-CSF and GM-CSF have been available for clinical use for only a few years but they have already profoundly affected the management of chemotherapy-induced neutropenia, the use of dose-intensive chemotherapy regimens, and the practice and safety of autologous stem cell transplantation. While these growth factors have rapidly been introduced as routine agents in the management of cancer patients, they have continued to generate a considerable amount of basic research on the biology of hematopoiesis as well as on the growth regulation of normal and tumor cells. One attractive possibility offered by growth factors is to protect hemopoietic stem and progenitor cells from the toxic effects of chemotherapy, while not diminishing its anti-tumor action. Any means of preferentially and reversibly suppressing the proliferation of normal hemopoietic stem and progenitor cell while leaving unmodified the proliferation of tumor cells and their susceptibility to chemotherapy, could potentially optimize treatment efficacy. In the present paper, we have briefly discussed the possibility to use the myeloid growth factors as myeloprotective agents in the context of drug-intensified chemotherapy on the basis of the results obtained during some clinical trials recently conducted in patients with advanced cancer.

Safety of human recombinant proteins

Recombinant human proteins play an important role in therapy, especially in stimulating the hematopoiesis after chemotherapy, e.g., erythropoietin and colony stimulating factors, while several promising candidates such as IL-6, IL-12, thrombopoietin and others are in clinical development. Since the recombinant proteins are copies of endogenous proteins, it was assumed that they would be well tolerated. While this assumption is correct for some, other proteins proved to be less well tolerated. Therefore, preclinical safety assessment of these proteins is necessary. Based on the experience with several proteins, some guidance for the safety assessment can be given. Furthermore, data are presented demonstrating that preclinical toxicity studies may have a predictive value for man. Limitations of the classical approach of safety tests and new concepts are discussed.

[Current status of the clinical application of hematopoietic growth factors in oncology]

With the identification and recombinant production of the hematopoietic growth factors, these cytokines have been evaluated in the treatment of primary bone marrow failure states and after myelosuppressive chemotherapy or radiotherapy. A lot of clinical trials with hematopoietic factors have been performed in patients with haematologic and oncologic diseases within the last decade. Granulocyte colony-stimulating factor [G-CSF], granulocyte macrophage colony-stimulating factor [GM-CSF], interleukin-3, interleukin-2, erythropoietin and in phase I/II trials thrombopoietin [TPO] are available for the clinical use. At the present, there is a broad use of growth factors. Most studies have been done with G-CSF and GM-CSF, their beneficial effects are proven regarding improvement of hematopoietic recovery after chemotherapy. This results in a marked reduction of infectious risks and a shortening of drug- and radiation-induced myelosuppression. CSFs are most important in mobilizing peripheral blood progenitor cells [PBPC] and have allowed high dose therapy to be given to patients who would not have been able to undergo conventional bone marrow transplantation. However, an improved outcome and improved survival rates with standard chemotherapy protocols couldn't be documented by studies up to now, even though higher chemotherapy doses are possible by the use of hematopoietic factors.

Proliferation and differentiation of myelodysplastic CD34+ cells

Myelodysplastic syndromes (MDS) are a heterogeneous group of disorders of hematopoiesis involving hyperproliferative and ineffective hematopoiesis associated with morphologic evidence of marrow cell dysplasia resulting in refractory cytopenia(s), and an increased risk of transformation into acute myeloblastic leukemia (AML). The administration of colony-stimulating factor(s) (CSFs) to patients with MDS increased blood neutrophil concentrations, in most patients, and was also expected to be beneficial and to prevent infections. However, the progression to AML during the treatment with CSFs was suspected in some patients. Therefore, extensive in vitro studies were expected to lead to the establishment of criteria for selection of patients who are likely to benefit from CSF's as well as to establish the overall value of the different types of CSFs therapy. For this purpose, in vitro colony assays provide an excellent tool for investigating the biologic characteristics of MDS progenitor cells. However, conditions of the culture must be such that each progenitor can express its full potential for proliferation and differentiation. Because of the above, MDS progenitor cells cannot be used because they carry an impairment in proliferation and differentiation. To address this problem, one needs to know how many cells are being handled and the maximum numbers of colonies and clusters expected. CD34, a stem cell phenotype, is at present one of the best markers of progenitor cells, and can be used for purposes of purification. Using a defined number of CD34+ cells, it was feasible to make direct investigations on MDS progenitor cells. In this review the properties of MDS progenitor cells are described, in association with proliferation and differentiation, with special emphasis on the phenotypic subpopulations of MDS CD34+ cells.

American Society of Clinical Oncology. Recommendations for the use of hematopoietic colony-stimulating factors: evidence-based, clinical practice guidelines

PURPOSE

Standard practice in protecting against chemotherapy-associated infection has been chemotherapy dose modification or dose delay, administration of progenitor-cell support, or selective use of prophylactic antibiotics. Therapy of chemotherapy-associated neutropenic fever or infection has customarily involved treatment with intravenous antibiotics, usually accompanied by hospitalization. The hematopoietic colony-stimulating factors (CSFs) have been introduced into clinical practice as additional supportive measures that can reduce the likelihood of neutropenic complications due to chemotherapy. Clinical benefit has been shown, but the high cost of CSFs has led to concern about their appropriate use. The American Society of Clinical Oncology (ASCO) wishes to establish evidence-based, clinical practice guidelines for the use of CSFs in patients who are not enrolled on clinical trials.

METHODS

An expert multidisciplinary panel reviewed the clinical data documenting the activity of CSFs. For each common clinical situation, the Panel formulated a guideline to encourage reasonable use of CSFs to preserve effectiveness but discourage excess use when little marginal benefit is anticipated. Consensus was reached after critically appraising the available evidence. Guidelines were validated by comparing them with recommendations for CSF use developed in other countries and by several academic institutions. Outcomes considered in evaluating CSF benefit included duration of neutropenia, incidence of febrile neutropenia, incidence and duration of antibiotic use, frequency and duration of hospitalization, infectious mortality, chemotherapy dose-intensity, chemotherapy efficacy, quality of life, CSF toxicity, and economic impact. To the extent that these data were available, the Panel placed greatest value on survival benefit, reduction in rates of febrile neutropenia, decreased hospitalization, and reduced costs. Lesser value was placed on alterations in absolute neutrophil counts (ANC).

CONCLUSIONS

CSFs are recommended in some situations, eg, to reduce the likelihood of febrile neutropenia when the expected incidence is > or = 40%; after documented febrile neutropenia in a prior chemotherapy cycle to avoid infectious complications and maintain dose-intensity in subsequent treatment cycles when chemotherapy dose-reduction is not appropriate; and after high-dose chemotherapy with autologous progenitor-cell transplantation. CSFs are also effective in the mobilization of peripheral-blood progenitor cells. Therapeutic initiation of CSFs in addition to antibiotics at the onset of febrile neutropenia should be reserved for patients at high risk for septic complications. CSF use in patients with myelodysplastic syndromes may be reasonable if they are experiencing neutropenic infections. Administration of CSFs after initial chemotherapy for acute myeloid leukemia does not appear to be detrimental, but clinical benefit has been variable and caution is advised. Available data support use of CSFs in pediatric cancer patients similar to that recommended for adult patients. Outside of clinical trials, CSFs should not be used concurrently with chemotherapy and radiation, or to support increasing chemotherapy dose-intensity. Further research is warranted as a means to improve the cost-effective administration of the CSFs and identify clinical predictors of infectious complications that may direct their use.

Use and toxicity of the colony-stimulating factors

The colony-stimulating factors (CSFs) have emerged as effective drugs in a variety of clinical situations. These drugs stimulate the production and activity of haematopoietic cells in vitro and in vivo. Two members of this group, granulocyte CSF (G-CSF) and granulocyte-macrophage CSF (GM-CSF), have been approved in the US and Europe for use following cytotoxic chemotherapy and autologous bone marrow transplantation. Other uses of the CSFs include myelodysplastic syndromes, aplastic anaemia, the acquired immunodeficiency syndrome (AIDS) and cyclic and congenital neutropenias. Although CSFs have generally been well tolerated in clinical use there are a number of theoretical concerns, including disease acceleration, biased stem cell commitment and bone marrow exhaustion. New CSFs are currently under development. Combinations of growth factors in the future may maximise effectiveness while minimising toxicity.

Stimulating new developments. Colony-stimulating factors

Drug-induced low white-blood-cell counts have long impaired our ability to treat patients. Colony-stimulating factors are now available for intravenous or subcutaneous administration. These glycoproteins act on hematopoietic cells by binding to specific cell surface receptors and by stimulating proliferation, differentiation, commitment, and activation of new white blood cells. A brief overview of patient population, indications, actions, and adverse reactions for hospital or home use is presented.

Recombinant human hematopoietic growth factors in the treatment of cytopenias

The hemolymphopoietic growth factors, including the colony-stimulating factors (CSF) and interleukins (IL), are described and categorized on the basis of their biological features in laboratory systems. Although these agents are varied and exceptions exist, in general they lack lineage specificity although they may express lineage-predominant activity. They act at multiple levels of hemolymphopoietic cell differentiation, demonstrate additive or synergistic effects when combined in vitro, require surface receptors on target cells to directly express their activity, and may be produced by a variety of cells. This framework of behavioral generalizations, completed by the specifics of each factor's activity, despite the artifactual and simplified nature of in vivo systems, forms the basis for concepts of in vitro activity and for clinical applications. Hemolymphopoietic growth factors studied in the clinic have demonstrated impressive and important activity, validating much of the in vitro data. Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have clearly reduced neutropenia and infection rates when administered following conventional chemotherapy and high-dose chemotherapy followed by autologous bone marrow transplantation. To a varying degree, similar results with G-CSF and/or GM-CSF have been described in other diseases including acute myelogenous leukemia (AML) treated following induction chemotherapy, myelodysplastic syndrome, hairy cell leukemia, aplastic anemia, and chronic neutropenias. In preliminary studies IL-3 has been shown to have similar qualitative activities. However, these agents have not demonstrated a reproducible salutary impact on platelet or red cell lineages. Adverse effects on platelet counts and/or platelet recovery have been noted. Additionally, hemolymphopoietic growth factor receptors have been identified on malignant cells, suggesting that these factors could stimulate neoplastic growth. Studies with GM-CSF and IL-3 have demonstrated blast proliferation in some cases of AML and myelodysplasia, underscoring the capacity of these agents to stimulate the growth of myeloid leukemia. No clinically evident impact of these factors upon the growth of solid tumors has been identified but this issue has not been adequately studied. The toxicity of these agents has been surprisingly limited and appears to be related to their biologic activities. Hemolymphopoietic growth factors as single agents have broad clinical applications in cytopenias. Several methods for enhancing the clinical activity of these agents are under study, including the use of combinations of growth factors synergistic in vitro.

The clinical use of colony stimulating factors

Colony stimulating factors and interleukins regulate proliferation, differentiation, and functional activation of hematopoietic cells of multiple lineages. These hematopoietic growth factors are proving effective in vivo in stimulation of granulopoiesis in clinical situations associated with myelosuppression. G-CSF and GM-CSF promote accelerated granulocyte recovery following chemotherapy, or allogeneic or autologous bone marrow transplantation, in patients with cancer. In congenital defects of granulocyte production or in acquired disorders such as idiopathic neutropenia or aplastic anemia, CSF administration can lead to recovery of functioning granulocytes. This has resulted in a reduction in the morbidity and mortality associated with these diseases and now permits both a dose and a schedule intensification of chemotherapy. In myeloid leukemia and myelodysplastic syndromes, CSF treatment, particularly G-CSF, has proved effective for certain patients in improving neutrophil, platelet, and occasionally red cell production while reducing blast cells. The recombinant growth factors are generally well tolerated with few limiting toxicities at dose levels that effectively stimulate hematopoiesis.

Colony-stimulating factors

Recombinant hematopoietic colony-stimulating factors have profound effects on developing and mature granulocytes, macrophages, and lymphocytes. Use of these agents for treatment of disease may result in a variety of adverse cutaneous reactions. The recent discovery of colony-stimulating factor production by keratinocytes and dermal cells suggests that these agents may also be significant in cutaneous homeostasis and in the pathogenesis of cutaneous diseases.

Effect of granulocyte colony-stimulating factor after intensive induction therapy in relapsed or refractory acute leukemia

Background. Although colony-stimulating factors have been shown to accelerate recovery from severe neutropenia after intensive chemotherapy or bone marrow transplantation, their use in acute leukemia has been controversial because in vitro they stimulate leukemic colonies as well as normal granulocyte colonies. Methods. We conducted a prospective, randomized, controlled study to determine the safety and efficacy of recombinant human granulocyte colony-stimulating factor (CSF) after a standard course of intensive therapy in 108 patients with relapsed or refractory acute leukemia (67 with acute myelogenous leukemia, 30 with acute lymphocytic leukemia, 9 in blast crisis from chronic myelogenous leukemia, and 2 with acute leukemia arising from myelodysplastic syndromes). Treatment with granulocyte CSF (200 micrograms per square meter of body-surface area per day in a 30-minute infusion) was begun two days after the end of the chemotherapy and continued until the neutrophil count rose above 1500 per cubic millimeter. Results. Treatment with granulocyte CSF accelerated the recovery of neutrophils significantly (P less than 0.01), shortening it by about a week, but it had no effect on platelet recovery. Although the incidence of febrile episodes was almost the same, documented infections were significantly less frequent in the group treated with granulocyte CSF (P = 0.028). There was no evidence that granulocyte CSF accelerated the regrowth of leukemic cells. Fifty percent of 48 patients in the CSF group who could be evaluated and 36 percent of 50 controls had complete remission. The rate of relapse was almost the same in the two groups. Conclusions. It appears that recombinant human granulocyte CSF is safe in acute leukemia, accelerating neutrophil recovery and thereby reducing the incidence of documented infection without affecting the regrowth of leukemic cells. It should be used with caution, however, pending further confirmation of these early results.

The role of hematopoietic growth factors in nuclear and radiation accidents

Molecularly cloned hematopoietic growth factors are likely to be useful in treating persons with bone marrow failure resulting from radiation exposure. Some effects, such as increased granulocytes or platelets, are of clear therapeutic benefit. Other effects, such as a direct action on survival of hematopoietic stem cells and improved granulocyte function, may also increase survival. Many important areas remain to be studied, including which molecularly cloned hematopoietic growth factor(s) to use, optimal dose and timing, and others. Some of these issues can be studied in clinical trials; others require in vitro or animal models. Despite the limited data currently available, it is clear that the availability of molecularly cloned hematopoietic growth factors heralds a new era in treating radiation and nuclear accidents.

Mitoxantrone/high-dose Ara-C and recombinant human GM-CSF in the treatment of refractory non-Hodgkin's lymphoma. A pilot study

Previous study has shown that the combination of mitoxantrone (Novantrone, NO) and Ara-C (AC) (NOAC) was active in refractory non-Hodgkin's lymphoma (NHL) but myelosuppression was dose-limiting. In a pilot study, we investigated the effects of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) after NOAC chemotherapy in patients with refractory NHL. NO was applied at a dosage of 10 mg/m2/day on days 2 and 3 and AC at 3 g/m2/12h on days 1 and 2. RhGM-CSF was administered at 250 ug/m2/day as a continuous i.v. infusion from day 6 until the neutrophils were greater than 3.0/nl for 3 consecutive days. Twenty-three patients from five of the nine participating centers were treated with NOAC chemotherapy plus rhGM-CSF, whereas 14 patients from the other four centers received chemotherapy alone. With rhGM-CSF, the median duration of severe neutropenia (less than 0.5/nl) after NOAC was 8 days versus a median of 13 days without rhGM-CSF (P = 0.0058), and that of thrombocytopenia (less than 20.0/nl), 3 days versus 7 days (P greater than 0.4, NS). The rates of infections and stomatitis were 25% and 17%, respectively, for patients treated with rhGM-CSF as compared to 53% (P = 0.0547, NS) and 60% (P = 0.0078), respectively, without rhGM-CSF. The following side effects were associated with the administration of rhGM-CSF: pleural and/or pericardial effusions in five patients, thrombosis in two patients, bone pain in two patients, and respiratory distress syndrome in one patient. A complete remission was achieved in nine of the 23 patients treated with NOAC plus rhGM-CSF, and in two of the 14 patients treated with chemotherapy alone. The median survival of patients treated with rhGM-CSF was not reached at 400 days and seemed to be longer than that of patients treated with chemotherapy alone (median, 109 days; P = 0.036). RhGM-CSF after chemotherapy can be applied safely to patients with NHL, shorten the period of severe cytopenia, reduce the rates of stomatitis, and did not seem to cause adverse effects on response.

Treatment of poor-prognosis, newly diagnosed acute myeloid leukemia with ara-C and recombinant human granulocyte-macrophage colony-stimulating factor

We administered recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) (120 micrograms/m2/d by continuous intravenous [IV] infusion) to 12 patients with newly diagnosed acute myeloid leukemia (AML) at relatively high risk of early death during remission induction. GM-CSF began 3 days after completion of induction chemotherapy (ara-C 1.5 g/m2 d x 4 days by continuous IV infusion after a 3 g/m2 bolus). Rates of fatal infection (42%), pneumonia and/or sepsis (83%), and CR (50%) did not differ significantly (P less than .05) from those observed after administration of the identical chemotherapy without GM-CSF to 53 historical controls with newly diagnosed AML at similarly high risk of early death. There were no significant differences between the GM-CSF-treated and the historical groups in the time required to reach neutrophil counts of 500 or 1,000/microL after administration of chemotherapy. Four patients died of infection before they could have benefited from the earliest recovery of neutrophil count observed in patients who entered CR. Growth of leukemia after GM-CSF administration was observed in only 1 of the 8 patients who survived long enough for response to induction therapy to be fully evaluated. This observation suggests that it might be safe to undertake larger, randomized studies, perhaps using earlier administration of GM-CSF, to definitively determine the role of GM-CSF added to chemotherapy in patients with newly diagnosed AML.

Recurrent spleen enlargement during cyclic granulocyte-macrophage colony-stimulating factor therapy for myelodysplastic syndrome

A 65-year-old woman with refractory anemia with excess of blasts received sequential courses of granulocyte-macrophage colony-stimulating factor therapy (GM-CSF) and low-dose cytosine arabinoside. Each course of GM-CSF induced a rapid and tremendous increase in leukocyte count as well as in spleen size, 111indium chloride scanning suggested a myeloid metaplasia of the spleen. This observation suggests that in some patients the granulopoietic response to the myeloid growth factor stimulation may be predominant in the spleen.

Recombinant human granulocyte-macrophage colony-stimulating factor in patients with advanced malignancy: a phase Ib trial

We evaluated the toxic, hematopoietic, and immunomodulatory effects of recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF). The rHuGM-CSF was administered at doses up to 50 micrograms/kg by daily 2-hour intravenous infusions to 11 patients with advanced malignancy. It induced dose-related increases in cells of the myeloid series, but it had no significant effect on reticulocyte or platelet counts. Bone marrow cellularity increased with higher doses of rHuGM-CSF, but there was a dose-related decrease in the number of colony-forming units--granulocyte-monocyte--and colony-forming units--granulocyte-erythrocyte-monocyte-megakaryocyte--per 10(5) bone marrow cells. The rHuGM-CSF caused transient increased expression of CD11b and CD16 on granulocytes but increased expression of HLA-DR and decreased expression of the high-affinity Fc receptor on monocytes and no change in monocyte production of H2O2. Thus, rHuGM-CSF has potent effects on granulocyte, eosinophil, and monocyte numbers in the peripheral blood and bone marrow. In addition, it enhances the expression of monocyte and granulocyte activation-associated surface markers.

Recombinant GM-CSF in patients with poor graft function after bone marrow transplantation

Poor graft function after bone marrow transplantation is an infrequent complication that is fatal for most patients secondary to severe infections or to bleeding. Even a second marrow infusion is usually not successful in restoring hematopoiesis. We treated nine patients with recombinant Escherichia coli derived human granulocyte-macrophage colony-stimulating factor (GM-CSF) for delayed engraftment or graft failure after autologous (n = 6) or allogeneic (n = 3) bone marrow transplantation (BMT). Six patients were given a dose of 10 micrograms/kg/d over 30 min; three patients received lower doses of 3-5 micrograms/kg/d. Seven patients lived longer than 3 days after commencing GM-CSF and could be evaluated for their response. Six of them had a marked rise in neutrophil counts; there was no effect on platelet and reticulocyte counts. Two patients died within the first 3 days after starting GM-CSF, although both seemed to have some response to GM-CSF (increasing blood neutrophils in one, and increasing macrophages in the bone marrow on autopsy in the other). Side effects most likely attributable to GM-CSF administration were mild and included diarrhea and abdominal pain, low grade fever and mild rash. Severity of graft-vs-host disease (GVHD) was not enhanced in the recipients of allogeneic marrow. We conclude that recombinant GM-CSF can be safely given to patients with poor graft function after marrow transplantation. In some patients, this may lead to a subsequently sustained neutrophil recovery.