Evidence-Based Use of Colony-Stimulating Factors in Elderly Cancer Patients

BACKGROUND

Neutropenia and its complications represent the major dose-limiting toxicity of cancer chemotherapy, especially in the elderly. Hematopoietic growth factors have been shown to reduce the severity and duration of febrile neutropenia (FN) and to sustain chemotherapy dose intensity.

METHODS

A systematic review was undertaken of studies of the relationship between age and the risk of neutropenia and its complications. Recent studies of the "Awareness of Neutropenia in Chemotherapy Study Group" related to the impact of age on neutropenic complications are also summarized.

RESULTS

The risk of FN associated with standard regimens increases with age and appears to be greatest during the first cycle of chemotherapy. FN continues to have a considerable clinical, economic, and quality-of-life impact on affected individuals. The risk of mortality associated with hospitalization with FN also increases with age but is largely associated with the higher rate of comorbidities observed in the elderly population. Despite increasing evidence that elderly patients experience similar benefit from cancer chemotherapy, reductions in dose intensity often compromise response rates and long-term survival. The hematopoietic growth factors reduce the risk of neutropenic events and the need for reduced dose intensity in elderly cancer patients. Primary prophylaxis with colony-stimulating factors (CSFs) reduces the risk of FN and its complications in elderly patients receiving moderately intensive systemic chemotherapy for responsive malignancies. CSFs also appear to reduce cost and improve quality of life in selected elderly patients receiving chemotherapy.

CONCLUSIONS

Primary prophylaxis with CSFs should be considered in elderly patients with responsive and potentially curable malignancies who receive moderately intensive chemotherapy.

Economic analysis of prophylactic pegfilgrastim in adult cancer patients receiving chemotherapy

OBJECTIVES

Neutropenia and its complications, including febrile neutropenia (FN), are a common side effect of cancer chemotherapy. Results of clinical trials showed that prophylactic use of granulocyte colony-stimulating factors (G-CSF) is effective in preventing FN. In this study, the cost effectiveness (measured as cost per quality-adjusted time [days]) of three treatment alternatives were evaluated: no G-CSF, filgrastim administered daily for 7-12 days after chemotherapy, and a pegylated form of G-CSF pegfilgrastim, administered once per cycle.

METHODS

A cost-utility model based on standard clinical practice of treating FN with immediate hospitalization or with ambulatory treatment, from a societal perspective was developed. Direct medical cost estimates for hospitalization were derived from claims data reported by 115 US academic medical centers. Indirect medical costs, productivity costs, probabilities, and utilities are based on published literature. Results were subjected to sensitivity analyses and 95% confidence intervals are based on a Monte Carlo simulation.

RESULTS

Mean estimated costs/day of hospitalization were $1984 (SD $1040, N = 24,687) for surviving patients and $3139 (SD $2014, N = 1437) for dying patients. Under baseline conditions, pegfilgrastim dominated both filgrastim and no G-CSF, with expected costs and effectiveness of $4203 and 12.361 quality adjusted life-days (QALDs) for no G-CSF, $3058 and 12.967 QALDs for pegfilgrastim, and $5264 and 12.698 QALDs for filgrastim.

CONCLUSIONS

This cost-utility analysis provides strong evidence that pegfilgrastim is not only cost-effective but also cost-saving in most common clinical and economic settings. There appear to be both clinical and economic benefits from prophylactic administration of pegfilgrastim.

Review of the value of colony stimulating factors for prophylaxis of febrile neutropenic episodes in adult patients treated for haematological malignancies

Chemotherapy-induced neutropenia is a major dose-limiting toxicity of systemic cancer chemotherapy that can lead to fever and infection, requiring prompt analysis and in-patient treatment with broad-spectrum antibiotics. Complicated neutropenia may lead to reduction and/or delay of systemic anti-cancer treatment, which may compromise outcome. Haematopoietic growth factors have the ability to augment haematopoietic cell cycling and are used to facilitate more dose-intense treatments and to decrease treatment-related complications. This review focuses on randomised trials that investigated the use of colony-stimulating factors (CSF) to prevent treatment-related febrile complications in haematological malignancies in (younger) adult patients. In general, these studies demonstrated that CSF reduced the duration of severe neutropenia but not always its febrile complications; therefore inconsistent results regarding clinically relevant reduction of hospitalisation, duration of therapeutic antibiotics, infection-related or disease-related mortality and economic effects were reported. Current developments in treatment of haematological malignancies will pose new challenges as a shift in infectious pathogens can be expected.

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.

Guidelines of the National Comprehensive Cancer Network on the Use of Myeloid Growth Factors with Cancer Chemotherapy: A Review of the Evidence

The prophylactic use of myeloid growth factors reduces the risk of chemotherapy-induced neutropenia and its complications, including febrile neutropenia and infection-related mortality. Perhaps most importantly, the prophylactic use of colony-stimulating factors (CSFs) has been shown to reduce the need for chemotherapy dose reductions and delays that may limit chemotherapy dose intensity, thereby increasing the potential for prolonged disease-free and overall survival in the curative setting. National surveys have shown that the majority of patients with potentially curable breast cancer or non-Hodgkin's lymphoma (NHL) do not receive prophylactic CSF support. In this issue, the National Comprehensive Cancer Network presents guidelines for the use of myeloid growth factors in patients with cancer. These guidelines recommend a balanced clinical evaluation of the potential benefits and harms associated with chemotherapy to define the treatment intention, followed by a careful assessment of the individual patient's risk for febrile neutropenia and its complications. The decision to use prophylactic CSFs is then based on the patient's risk and potential benefit from such treatment. The routine prophylactic use of CSFs in patients receiving systemic chemotherapy is recommended in patients at high risk (>20%) of developing febrile neutropenia or related complications that may compromise treatment. Where compelling clinical indications are absent, the potential for CSF prophylaxis to reduce or offset costs by preventing hospitalization for FN should be considered. The clinical, economic, and quality of life data in support of these recommendations are reviewed, and important areas of ongoing research are highlighted.

Effect of outpatient treatment of febrile neutropenia on the risk threshold for the use of CSF in patients with cancer treated with chemotherapy

OBJECTIVES

Febrile neutropenia (FN) in patients with cancer treated with chemotherapy has traditionally been managed with inpatient broad-spectrum antibiotics until the infection and neutropenia have resolved. A newer strategy is outpatient oral or intravenous antibiotics in selected patients after an initial hospitalization. We sought to determine these costs, both overall and relative to those of traditional management, and the optimal role of prophylactic colony-stimulating factor (CSF) in patients at greatest risk for FN.

METHODS

Existing economic decision models were modified by incorporating a treatment strategy for FN in which patients are classified as high- and low-risk according to criteria described by Talcott. Low-risk patients were assumed to be treated as outpatients. Overall costs with the revised economic model were assessed and sensitivity analyses were performed.

RESULTS

The costs of an episode of FN were estimated as 1) no CSF: dollar 13,355; 2) CSF with hospitalization for FN: dollar 8677; and 3) CSF with risk stratification and outpatient management in low-risk patients: dollar 8188. The risk threshold for the cost-effective use of CSF was only slightly lower with outpatient treatment. When all patients with FN are treated as inpatients and the cost of hospitalization is dollar 1750/day the risk threshold for FN at which prophylactic CSF becomes cost-effective is 16%. It is 15% when low-risk patients are treated as outpatients.

CONCLUSIONS

Outpatient treatment slightly decreases the risk threshold for FN at which prophylactic CSF becomes cost-effective. The limited economic effect of this strategy may be because the patients who were at greatest risk of complications had significantly longer lengths of stay and accounted for most of the hospitalization costs.

Supportive care of the older cancer patient

Aging is associated with decreased functional reserve of multiple organ systems and with changes in the pharmacokinetics and pharmacodinamics of drugs. Older individuals express enhanced susceptibility to the complications of cytotoxic chemotherapy, especially to myleotoxicity, mucositis, cardiotoxicity and neurotoxicity. The management of older individuals with chemotherapy involves then prevention of these complications. General precautions include proper patient selection, based on the comprehensive geriatric assessment (CGA), dose adjustment for agents that are renally excreted to the patient creatinine clearance and maintenance of hemoglobin levels > or =12 g/dl. Filgrastim and pegfilgrastim proved effective in reducing by 50-75% the risk of neutropenic fever in older individuals treated with CHOP and CHOP-like chemotherapy and should be used for the prophilaxis of infections. When feasible, the oral agent capecitabine, should be used in lieu of intravenous fluorinated pyrimidines, to prevent mucositis. In patients at risk of cardiomyopathy from anthracyclines, dexrazoxane or liposomal compounds may be indicated. When toxicity is properly prevented, cytotoxic chemotherapy may be as effective in older individuals as it is in the younger ones.

The economics of the colony-stimulating factors in the prevention and treatment of febrile neutropenia

Healthcare costs continue to rise with hospitalization representing the single largest component of direct medical costs associated with cancer care. Neutropenia and its complications including febrile neutropenia remain the major dose-limiting toxicity associated with systemic cancer chemotherapy. Febrile neutropenia often occurs early in the course of chemotherapy and is associated with substantial morbidity, mortality and cost. The colony-stimulating factors (CSFs) have been used effectively in a variety of clinical settings to prevent or treat febrile neutropenia and to assist patients receiving dose-intensive chemotherapy. A meta-analysis of the available randomized controlled trials (RCTs) has confirmed the efficacy of prophylactic CSFs. Economic models based on measures of resource utilization derived from RCTs have provided estimates of expected treatment costs along with febrile neutropenia risk threshold estimates for the cost saving use of the CSFs. Recent studies have demonstrated the potential value of targeting the CSFs toward patients at greatest risk based on accurate and valid predictive models.

The importance of prophylactic management of chemotherapy-induced neutropenia

The development of colony-stimulating factors (CSFs) has provided clinicians with a valuable tool for proactive management of chemotherapy-induced neutropenia. However, clinicians are also presented with the challenge of appropriately targeting this treatment to patients at serious risk of neutropenic complications, while maintaining an economic approach to prescribing. This article discusses the seriousness of chemotherapy-induced neutropenia and reviews current approaches to the management of this condition. Febrile neutropenia risk models, new therapy options and international guidelines for the use of CSFs are also discussed.

Effects of Indirect and Additional Direct Costs on the Risk Threshold for Prophylaxis with Colony-Stimulating Factors in Patients at Risk for Severe Neutropenia from Cancer Chemotherapy

STUDY OBJECTIVES

Previous studies have used direct hospital costs to determine the threshold at which the cost of prophylactic use of colony-stimulating factor (CSF) is offset by savings from the lower risk of hospitalization for febrile neutropenia. By conducting a survey of patients in whom febrile neutropenia had developed during treatment with chemotherapy, we sought to reassess these costs by including estimates of indirect costs associated with febrile neutropenia as well as new categories of direct costs that were not previously available. Costs were included in an existing cost-minimization model, and their effect on the risk threshold at which the prophylactic use of CSF becomes cost saving was determined.

PATIENTS

A sample survey of 26 patients with ovarian cancer who were treated with chemotherapy and developed febrile neutropenia.

INTERVENTION

Analysis of data from patients' questionnaires containing survey items on indirect costs and additional direct costs associated with febrile neutropenia.

MEASUREMENTS AND MAIN RESULTS

Estimates of indirect costs and other direct costs from the questionnaires were included in an existing cost-minimization model, and risk thresholds were recalculated. Before modification, the model showed cost neutrality for prophylactic use of CSF when the risk of hospitalization for febrile neutropenia was approximately 23%. Including previously excluded direct costs and indirect costs ranging from 1000-5000 dollars attributable to severe neutropenia in the model lowered the risk threshold for hospitalization for febrile neutropenia at which the prophylactic use of CSF becomes cost neutral to between 22% and 18%.

CONCLUSION

Including additional direct as well as indirect costs associated with chemotherapy-induced neutropenia permits a more realistic assessment of the possible effect of prophylactic use of CSF from a societal perspective. Despite the limited size of the survey, this study shows a cost-benefit rationale to support prophylactic use of CSF in a greater proportion of patients treated with chemotherapy.

Risk assessment in oncology clinical practice. From risk factors to risk models

Myelosuppression and neutropenia represent the major dose-limiting toxicity of cancer chemotherapy. Chemotherapy-induced neutropenia may be accompanied by fever, presumably due to life-threatening infection, which generally requires hospitalization for evaluation and treatment with empiric broad-spectrum antibiotics. The resulting febrile neutropenia is a major cause of the morbidity, mortality, and costs associated with the treatment of patients with cancer. Furthermore, the threat of febrile neutropenia often results in chemotherapy dose reductions and delays, which can compromise long-term clinical outcomes. Prophylactic colony-stimulating factor (CSF) has been shown to reduce the incidence, severity, and duration of neutropenia and its complications. Guidelines from the American Society of Clinical Oncology recommend the use of CSF on the basis of the myelosuppressive potential of the chemotherapy regimen. The challenge in ensuring the appropriate and cost-effective use of prophylactic CSF is to determine which patients would be most likely to benefit from it. A number of patient-, disease-, and treatment-related factors are associated with an increased risk of neutropenia and its complications. A number of clinical predictive models have been developed from retrospective datasets to identify patients at greater risk for neutropenia and its complications. Early studies have demonstrated the potential of such models to guide the targeted use of CSF to those patients who are most likely to benefit from the early use of these supportive agents. Additional prospective research is needed to develop more accurate and valid risk models and to evaluate the efficacy and cost-effectiveness of model-targeted use of CSF in high-risk patients.

Balancing the benefits and costs of colony-stimulating factors: a current perspective

Neutropenia is the most common dose-limiting toxicity associated with cancer chemotherapy. Neutropenic complications, including febrile neutropenia, occur in a substantial proportion of patients with chemotherapy-induced neutropenia. Although neutropenia and its complications can be reduced with colony-stimulating factors (CSFs), it is not considered cost-effective to administer them prophylactically to all patients. The current American Society of Clinical Oncology guidelines recommend primary prophylaxis with the CSFs in patients receiving chemotherapy regimens that produce febrile neutropenia in 40% or more of those treated. This recommendation was supported by an early economic analysis based on a decision model incorporating hospital cost data to determine the risk threshold for the cost-saving use of the CSFs. Updating this model to include current estimates of hospitalization costs, indirect costs such as productivity losses, and out-of-pocket patient expenses reduced the risk threshold for cost savings with CSF to 18%. Recent efforts have focused on identifying individual patient characteristics that might be used to target prophylactic CSF in patients who are at greatest risk. Should such factors be identified and validated, assessing each patient's individual risk for neutropenic complications may prove to be a better strategy for the cost-effective use of the CSFs than the risk threshold approach. Preliminary results suggest that the targeted application of CSF support based on a risk model may improve the associated cost savings.

Cost analyses of adjunct colony stimulating factors for older patients with acute myeloid leukaemia : can they improve clinical decision making?

Colony stimulating factors (CSF) have been shown to reduce the duration of neutropenia following intensive chemotherapy in a variety of settings, with many of these studies targeting older patients with leukaemia. We review the clinical and economic findings for use of growth factors for older adults with acute myelogenous leukaemia (AML). The cost analyses were based on the perspective of the third party payer. One study, conducted by the Southwest Oncology Group (SWOG) randomised 207 AML patients to receive granulocyte colony-stimulating factor (G-CSF) or placebo and found no significant difference in number of infections and in days of hospitalisation, 3 fewer days with an absolute neutrophil count <500 cells/microL with G-CSF, and an estimated incremental cost of only US 120 dollars with G-CSF over placebo (1997 costs). A second study, conducted by the Eastern Cooperative Oncology Group (ECOG), randomised 119 AML patients to receive granulocyte-macrophage colony-stimulating factor (GM-CSF) or placebo and found a reduction in severe infections, 4 fewer days with an absolute neutrophil count <500 cells/microL, no significant difference in the duration of hospitalisation, and estimated cost savings of US 2310 dollars with GM-CSF (1997 costs). These data may be useful to physicians faced with concerns over clinical and economic factors associated with CSF use as adjunct therapy for older persons with AML.

New directions in the management of chemotherapy-induced neutropenia: risk models, special populations, and quality of life

New directions in managing chemotherapy-induced neutropenia include the development and validation of patient-based predictive risk models to guide the use of prophylactic colony-stimulating factors (CSFs) and an emerging recognition of the possible impact of chemotherapy-induced neutropenia on patient quality of life. Predictive risk models are being developed to identify patients who are at greater risk of neutropenic complications so that prophylactic CSF can be targeted to them in a timely and cost-effective manner. Current practice dictates the use of CSF prophylaxis primarily on the basis of the chemotherapy regimen; the risk-model approach is based on individual patient risk factors, which may be unconditional (before treatment) or conditional (after the first cycle). Within this new paradigm are patients with special circumstances, in whom prophylactic CSF treatment is currently recommended. Clinical evidence suggests that elderly patients are at particular risk for myelosuppression and should be considered for prophylactic CSF treatment starting with the first chemotherapy cycle. Analytical tools to measure the facets of quality of life related to neutropenia are being tested for validity and will be incorporated in future clinical trials. Thus, the future of neutropenia management promises to further refine the cost-effective use of CSF, while improving our understanding of the impact that chemotherapy-induced neutropenia has on quality of life.

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.

A predictive model for neutropenia associated with cancer chemotherapy

Studies of primary prophylaxis of febrile neutropenia (FN) with recombinant human granulocyte colony-stimulating factor (rHu-G-CSF, filgrastim) administered to all patients starting their initial course of chemotherapy have demonstrated clinical effectiveness and an economic advantage in a wide range of settings. A recent meta-analysis confirmed the ability of filgrastim to reduce the risk of FN and documented infection in a variety of malignancies in both adults and children. The threshold risk for FN at which a cost saving is achieved by using filgrastim is inversely related to the daily cost of the drug and duration of hospitalization. Clinical practice guidelines for the use of filgrastim were developed based on these observations. Recent studies incorporating indirect institutional costs demonstrated that a cost saving can be achieved at substantially lower FN risk thresholds than previously estimated. Despite the demonstrated efficacy of filgrastim in primary prophylaxis, its value may be further increased by appropriately selecting patients and better understanding the importance of sustaining dose intensity in specific malignancies. Clinical prediction models capable of identifying individuals at high risk for neutropenic complications yield further reductions in FN risk thresholds and treatment costs in patients receiving cancer chemotherapy. These models also may be used to evaluate the cost-effectiveness or cost-efficiency of filgrastim. A clinical prediction model recently was presented and validated incorporating both baseline clinical characteristics as well as the results of the first cycle of chemotherapy in patients with early-stage breast cancer. A cost-effectiveness ratio of $34,297/year of life saved was estimated based on dose-response assumptions derived from a previously reported adjuvant breast cancer trial studying the impact of dose reduction on disease-free survival. The cost-effectiveness of filgrastim was evident over a wide range of clinical and cost assumptions. Clinical prediction models permit the rational and cost-effective identification of patients for filgrastim support. Existing clinical practice guidelines should be reevaluated in light of new information available on both the total costs associated with FN as well as the cost-effectiveness of these agents in patients receiving chemotherapy for sensitive and potentially curable malignancies.

Update of the economic analyses of the use of the colony-stimulating factors

The colony-stimulating factors have been used effectively in a variety of clinical settings to prevent febrile neutropenia and to assist patients receiving dose-intensive chemotherapy with or without stem cell support. Several studies have confirmed the clinical efficacy of the colony-stimulating factors used prophylactically in both solid tumors and the hematologic malignancies. The cost of these agents, along with their large scale clinical use, has prompted a number of economic investigations. Economic analyses based on measures of resource utilization derived from randomized clinical trials have provided febrile neutropenia risk threshold estimates for the cost saving use of prophylactic colony-stimulating factor. A number of important studies concerning the clinical and economic impact of these agents have been reported over the past year. These include a revised cost minimization study based on improved febrile neutropenia cost information and a cost-effectiveness analysis in the adjuvant breast cancer setting based on a clinical prediction model to select patients at high risk for neutropenic complications. Continuing clinical and economic evaluation along with updating of clinical practice guidelines is needed due to rapid technologic and clinical advances in this area.

Economic impact of granulopoiesis stimulating agents on the management of febrile neutropenia

The granulopoiesis-stimulating agents (GSAs) have been effectively utilized in a variety of fashions to treat or prevent febrile neutropenia or to assist patients receiving dose-intensive chemotherapy with or without stem cell support. The high cost of these agents, along with their wide-scale clinical application, has fostered a number of economic analyses. Cost minimization models based on randomized trials and driven by hospitalization costs have provided febrile neutropenia risk thresholds for the use of the GSAs which have been incorporated into clinical practice guidelines. A number of important studies concerning the clinical and economic impact of these agents have been reported over the past year. The clinical role and economic impact of the GSAs in the management of either established febrile neutropenia or afebrile neutropenia remains uncertain. While several studies have confirmed the clinical value of the prophylactic use of these agents in both solid tumors and hematological malignancies, few have addressed their effect on cost or quality of life. The GSAs have demonstrated clinical as well as potential economic benefit in patients receiving high-dose chemotherapy with either bone marrow or peripheral blood stem cell support. Recent studies suggest a clinical and economic advantage for growth factor mobilization and peripheral blood stem cell support compared with bone marrow transplantation in patients receiving high-dose chemotherapy. The rapid evolution of technological and supportive care methods in this area will necessitate further clinical and economic evaluation.

A combination of low-dose cyclophosphamide and colony-stimulating factors is more cost-effective than granulocyte-colony-stimulating factors alone in mobilizing peripheral blood stem and progenitor cells

BACKGROUND

The use of peripheral blood progenitor cells (PBPCs) instead of autologous bone marrow leads to more rapid engraftment following high-dose chemotherapy. Mobilization regimens differ with respect to toxicity, efficiency, and cost.

STUDY DESIGN AND METHODS

Two cohorts of patients with breast cancer received one of two mobilization regimens: granulocyte-colony-stimulating factor (G-CSF) at 10 micrograms per kg was given subcutaneously for 5 days, with leukapheresis begun on Day 6, or low-dose cyclophosphamide followed by sequential granulocyte-macrophage-CSF (GM-CSF) at 5 micrograms per kg for 5 days and by G-CSF at 10 micrograms per kg, with leukapheresis begun on Day 11. Results of CD34+ cell collection, engraftment, and costs of mobilization were determined.

RESULTS

The combination chemotherapy and growth factor regimen was more efficient in mobilizing CD34+ cells. Sixty-six percent of patients reached a target 4 x 10(6) CD34+ cells per kg in a single leukapheresis session with the combination regimen, compared to 14 percent who received G-CSF alone (p < 0.01). The mean number of leukapheresis sessions required to reach a target of 4 x 10(6) CD34+ cells per kg was 1.3 for the combination regimen and 2.7 for the regimen of G-CSF alone (p < 0.01). One patient in the chemotherapy and growth factor group developed febrile neutropenia. Engraftment was similar in both cohorts of patients. The cost of mobilization, including all supplies and cryopreservation, was $7381 for the G-CSF regimen and $5508 for the chemotherapy regimen (p < 0.05). This reduction was attributed to the lower number of leukapheresis and cryopreservation sessions, which outweighed the slight increase in expense for chemotherapy and growth factor in the combination regimen.

CONCLUSION

This combination mobilization regimen allowed the predictable and efficient collection of CD34+ cells from the peripheral blood in a limited number of leukapheresis sessions, which reduced the cost of mobilization by approximately 25 percent.

Colony-stimulating factors and peripheral blood progenitor cell transplantation. Benefits and costs

High dosage chemo- or radiotherapy followed by the administration of autologous bone marrow-derived stem cells [i.e. autologous bone marrow transplantation (ABMT)] is an established protocol for treating acute myeloid leukaemia and malignant lymphoma. The approach is also under investigation in the treatment of acute lymphocytic leukaemia, multiple myeloma and solid tumours. In all of these diseases, the optimisation of indications, conditioning schemes, stem cell harvest techniques and supportive care with growth factors is subject to continuous preclinical research and clinical phase II and III studies. Recently, the administration of peripheral blood stem cell preparations to cancer patients as rescue therapy after high dosage antitumour therapy has been received with much enthusiasm. At first glance, the technique looks rather easy to perform. The faster recovery of haemopoiesis, compared with ABMT, leads to shorter durations of hospitalisation. Moreover, in most studies, peripheral blood progenitor cell transplantation (PBPCT) resulted in fewer septic episodes, fewer intensive care admissions, fewer red blood cell and platelet transfusions, reduced use of anti-infectives and parenteral nutrition, and reduced hospital costs compared with ABMT. The overall conclusion is that the treatment costs of PBPCT are 15 to 30% lower than the treatment costs of ABMT. However, a formal comparison between PBPCT and ABMT, assessing the differences in toxicity, costs and quality of life, is still awaited.

Economic analysis of the clinical uses of the colony-stimulating factors

Colony-stimulating factors can reduce the morbidity and possibly the mortality from some types of cancer treatment. Reductions in hospitalization and supportive care, eg, transfusion requirements and antibiotics, have been documented in several clinical trials and can lead to lower total care costs. However, the high cost of colony-stimulating factors and the necessity to treat large numbers of patients who do not benefit can offset the economic gains, unless the savings in hospitalization and supportive care are substantial. Primary prophylaxis with colony-stimulating factors is cost-saving only if the rate of hospitalization for febrile neutropenia is 40% or more; no current standard regimens are near that figure. In general, the American Society of Clinical Oncology clinical practice guide-lines for the use of colony-stimulating factors lead to effective and cost-conscious use of these expensive growth factors. Colony-stimulating factors are not recommended for primary prophylaxis of febrile neutropenia, are recommended for secondary prophylaxis if dose-reduction is not appropriate, and are recommended for stimulation of hematopoietic progenitor cells and reconstitution after high-dose chemotherapy. Further expansion of use based on economic factors will depend on documented survival benefit, major improvements in supportive care due to colony-stimulating factors, or markedly lower costs of colony-stimulating factors.

A cost analysis of hematopoietic colony-stimulating factors

The administration of hematopoietic colony-stimulating factors (CSFs) to reduce the severity and duration of neutropenia associated with systemic chemotherapy has become widespread, although the appropriate use of these agents has not yet been fully defined. A cost model based on decision theory is presented for three therapeutic choices in these patients: no CSF, prophylactic CSF, and therapeutic CSF. Baseline probabilities were derived from a prospective, randomized, placebo-controlled trial of G-CSF in patients receiving systemic chemotherapy. Application of the model to institutionally generated cost figures provides comparative estimates of excess cost favoring the prophylactic use of CSFs. Model thresholds were calculated based on sensitivity analysis comparing no CSF to prophylactic CSF, and therapeutic CSF to prophylactic CSF. Guidelines are provided based on this model that are consistent with those adopted by the American Society of Clinical Oncology.

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.

Methodological issues in economic assessments of new therapies. The case of colony-stimulating factors

Pharmacoeconomic evaluations estimate the value of medical interventions by comparing their clinical consequences and costs. Economic analyses, based on resource use data collected during 3 clinical trials of lenograstim, were performed as part of a lenograstim economic evaluation programme. Undertaking economic evaluations alongside clinical trials presents a number of methodological challenges, since the trials may be performed in atypical settings, have inappropriate follow-up, or use end-points that are not useful for economic evaluation. This paper reports on how these challenges were met in the lenograstim economic evaluation programme. In particular, it was decided that the evaluations would be based on an intent-to-treat perspective, with the same period of follow-up (for costs) for both lenograstim and vehicle groups.

Colony-stimulating factors. Present status and future potential

Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used successfully to enhance neutrophil recovery in patients with various malignancies undergoing standard or high dose chemotherapy, with or without autologous or allogeneic bone marrow transplantation support, and offer potential advantages in these settings in terms of reducing the total costs of healthcare and/or improving therapeutic outcomes. Clinical trials are now aimed at identifying which patients and which nonhaematological malignancies will respond best to colony-stimulating factor (CSF) support, and which of the 2 factors is the most appropriate in each setting. Two areas of considerable interest at present are the potential for chemotherapy dose optimisation and intensification with CSF therapy, and the use of CSFs to permit the harvest and reinfusion of peripheral blood progenitor cells as an alternative to autologous or allogeneic bone marrow transplantation. In the case of dose-intensified chemotherapy, costs of treatment increase but the gain may be an increase in survival rates or disease-free intervals. The potential of G-CSF and GM-CSF therapy in other conditions, notably haematological malignancies such as myelodysplasia and myeloid leukaemias, and AIDS, means that these agents are likely to make a significant impact on the treatment of a wide range of debilitating conditions in the future.

Cost considerations in therapy with myeloid growth factors

Costs of biologic response modifiers, specifically myeloid growth factors, are discussed relative to cost offsets they may produce in the total amount spent on health care in patients with certain disease states. Even though the biologic response modifiers granulocyte colony-stimulating factor (filgrastim) and granulocyte-macrophage colony-stimulating factor (sargramostim or molgramostim) are similar in name, they are chemically and biologically different. These differences result in different clinical applications. Administered after myelosuppressive antineoplastic therapy, filgrastim decreases the risk of infection. The growth factors may also be useful in patients undergoing bone marrow transplantation, in nonneutropenic patients with bacterial infections, and in patients with other disease states. Although the myeloid growth factors are somewhat expensive in terms of acquisition cost, their use is usually associated with a decrease in the risk of medical complications requiring health care expenditures, often for hospitalizations or antimicrobials. The precise cost of acquiring and administering myeloid growth factors depends on three interdependent variables: the factor used, the dosage of the drug, and the duration of therapy. Cost offsets may be more difficult to define, but they would include direct cost offsets, such as reduced episodes of febrile neutropenia and fewer, less-intense days of hospitalization or treatment. Sargramostim and molgramostim have demonstrated efficacy when given after bone marrow transplantation; filgrastim has been shown to lower infection rates by at least 50% after myelosuppressive antineoplastic therapy and in patients with severe chronic neutropenia.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective physician review of orders for colony-stimulating factors

A program is described in which physicians prospectively review orders for the use of colony-stimulating factors (CSFs) at a tertiary-care private teaching hospital. Hospital officers and administrators and the heads of medical subspecialties were presented with three options for managing the use of CSFs. Prospective review by physicians was selected, and a task force of medical subspecialists was established to develop criteria for use and to review orders. Initially, every order was prospectively reviewed, but criteria were developed under which some orders do not require physician review. CSF use is documented retrospectively by a drug-use evaluation pharmacist and reviewed for appropriateness by the physician task force. Between March and October 1991, 115 patients were given courses of CSFs, and the use of the physician review system resulted in appropriate use of the drugs for 98% of the oncology patients and 61% of the patients infected with the human immunodeficiency virus. The prospective physician reviewer system has been accepted by the medical staff at the facility and has helped to ensure appropriate use of CSFs.