Pharmacoeconomics of Cancer Therapy
Susan E. Beltz, PharmD, and Gary C. Yee, PharmD, FCCP
Cost analyses of available interventions can help to determine
the value of an intervention from several points of view.
Background: In 1990, annual costs of the diagnosis and treatment of cancer reached nearly 0 billion and currently constitutes approximately 10% of health care expenditures in the United States. As new and often more expensive therapies for cancer treatment become available, the health care decision-maker must consider the cost effectiveness of the therapy.
Methods: Key principles of economic analyses and the inherent differences among these analyses are reviewed.
Results: While pharmacoeconomic analyses are increasingly being used in treatment decision-making, several issues relating to study design, data collection, and research methods are controversial.
Conclusions: Pharmacoeconomics analyses are necessary in the current health care environment, but the assumptions used within the analyses warrant careful evaluation.
Introduction
As health care expenditures in the United States continue to increase, many involved in the provision of health care are being asked to make difficult decisions concerning new interventions in an environment of limited resources. Economic analysis is a tool that determines the value (ie, quality divided by cost) of an intervention and is used by those who are involved in decisions concerning the allocation of limited resources. It can be used to evaluate many types of interventions, including screening and diagnostic tests or procedures and medical or surgical interventions. Pharmacoeconomics refers to the economic analysis of a drug or drug regimen. In simple terms, pharmacoeconomics is a tool to help health care decision-makers determine if a drug is “worth the price.” In the following article, we briefly review the economic evaluation of cancer therapies.
Economic Burden of Cancer
The economic burden of cancer is considerable and is a growing concern to purchasers and payers. The National Cancer Institute (NCI) estimates that the overall annual costs of cancer diagnosis and treatment was nearly 0 billion in 1990, a figure that includes billion for direct medical costs, billion for morbidity costs (cost of lost productivity), and billion for mortality costs.1 More recent estimates suggest that the direct medical costs of cancer in the United States represent approximately 10% of all health care expenditures, or about 0 billion each year.2
Several new cancer therapies have been marketed in the past few years (Table 1), and numerous promising drugs are being developed that offer hope for cancer patients. For example, trastuzumab (Herceptin [Genentech, Inc, San Francisco, Calif]) is a monoclonal antibody that shows promise in the treatment of metastatic breast cancer in the subset of women who overexpress the HER2 (human epidermal growth factor 2) oncogene. Two thrombopoietic growth factors are also being developed: thrombopoietin (TPO) and pegylated megakaryocyte growth and development factor (peg-rhMGDF). The availability of some of these new therapies is related in part to new initiatives by the Food and Drug Administration (FDA) to improve patient access to promising therapies. Historically, prior to drug approval, the FDA has required that a manufacturer of a pharmaceutical with antineoplastic activity prove that the agent demonstrate reasonable safety, efficacy, and improvements in survival time or quality of life. Unfortunately, this system often delayed access to potentially life-saving therapies and occasionally forced American cancer patients to seek alternative therapies available only outside the United States. In response to these concerns, the FDA announced in 1996 an initiative to accelerate the approval process. This initiative allows the FDA to now approve a new pharmaceutical based on objective evidence of tumor shrinkage and permits the manufacturer to provide additional evidence of increased survival and/or improved quality of life associated with that therapy after the marketing of the drug.
Table 1. — Recently Approved New Drugs Used in the Treatment of Cancer
Drug
Tradename
FDA-Approved Indication
Approval Date
Amifostine
Ethyol
Prevention of cisplatin-induced nephrotoxicity
Dec 1995
Capcitabine
Xeloda
Treatment of breast carcinoma
April 1998
Carmustine implant
Gliadel
Treatment of glioblastoma
Sept 1996
Dexrazoxane
Zinecard
Prevention of anthracycline-induced cardiomyopathy
May 1995
Dolasetron
Anzemet
Chemotherapy-induced nausea and vomiting
Sept 1997
Docetaxel
Taxotere
Treatment of breast carcinoma
May 1996
Irinotecan
Camptosar
Treatment of colorectal carcinoma
June 1996
Gemcitabine
Gemzar
Treatment of pancreatic carcinoma
May 1996
Oprelvekin
Neumega
Chemotherapy-induced thrombocytopenia
Nov 1997
Rituximab
Rituxan
Treatment of non-Hodgkin’s lymphoma
Nov 1997
Topotecan
Hycamtin
Treatment of ovarian cancer
May 1996
Tretinoin
Vesanoid
Treatment of acute promyelocytic leukemia
Nov 1995
Vinorelbine
Navelbine
Treatment of non-small cell lung cancer
Dec 1994
The availability of new and often expensive therapies presents health care decision-makers with the challenge of determining the value of the new agents. The Health Services Research Committee of the American Society of Clinical Oncology (ASCO) recognizes patient outcomes, particularly survival and quality of life, as important considerations in assessing the role of a particular therapy.3 The Committee also included cost effectiveness as an important outcome to consider, particularly when the benefits of treatment are modest or the costs are high. These cost-effectiveness analyses can provide oncologists, payers, and purchasers with a reference point from which to compare the value of different cancer therapies as well as the value compared to other medical treatments.
Pharmacoeconomic Studies
Economic analysis is a tool to determine the value of a specific drug or drug regimen. These analyses are particularly important for expensive agents that can add considerable cost to overall treatment costs. Few economic analyses of drugs used to treat cancer have been conducted, and even fewer have been published.4 Following is a discussion of key principles of economic analyses and a review of selected published pharmacoeconomic studies. Reviews of principles of economic evaluation are published elsewhere.5-7
Perspective
The perspective (point of view) of the analysis is important because it determines the types of costs included, the cost of each resource unit, and, in some instances, which measures of outcomes are included. The costs of care generally fall into two categories: (1) health care resources (also referred to as direct medical costs) and (2) patient and family resources.
The health care resources consumed include the costs of providing that intervention — hospitalization, physician visits, procedures, laboratory tests, nursing home visits, drugs, etc. It includes both fixed (or overhead) and variable costs. Patient and family resources consumed include any out-of-pocket expenses incurred by the patient, family members, or other caregivers, such as transportation costs, meals, and housing, and the value of their time, including the value of time of the patient seeking and receiving medical care or of family members serving as caregivers. The time lost could be from either leisure activities or work.
The societal perspective is the broadest, and studies conducted from this perspective usually include all costs, regardless of who incurs them. Some economic analyses may state that the analysis is conducted from a societal perspective but then omit the cost of patient or family resources consumed. Although the societal perspective is recommended by the Public Health Service Panel on Cost-Effectiveness Studies,7 most studies are not conducted from this perspective because of the difficulty (and expense) associated with measurement of costs other than direct medical costs.
Most studies are conducted from the payer or provider perspective, a perspective that usually includes only direct medical costs. Studies conducted from a provider perspective should be analyzed carefully because they often include only those consumed by that provider rather than all health care resources consumed. For example, studies conducted from the hospital perspective may not include professional fees, outpatient services, or prescription drugs dispensed outside of the hospital. As health care becomes more integrated, however, institutions will increasingly be asked to pay for all of the medical costs of cancer therapy, including supportive care (growth factors, antiemetics, etc). When a payer perspective is used, it is important to understand the differences between various payers. Because cancer is primarily a disease of older adults, Medicare is a major payer of cancer care in the United States. Therefore, many economic evaluations of new cancer therapies use cost estimates from Medicare data. For more than a decade, Medicare has paid a fixed amount for a hospitalization based on the diagnosis-related group. If a study is conducted from a payer perspective, and that payer pays a fixed amount per hospitalization, any changes in the costs that the provider incurred in caring for that patient would not affect payer costs. However, those changes could determine the amount of the profit or loss that the provider incurs in providing care for that patient.
It is important to recognize that outpatient drug costs may not be included in studies conducted from some perspectives. For example, only a portion of outpatient drug costs would be included in studies analyzed from a hospital or health system perspective because many patients obtain their drugs from their local community pharmacy. Furthermore, traditional fee-for-service Medicare does not reimburse for the cost of most orally administered drugs.
Costs
The perspective of the study determines the types of costs included and the cost for each resource unit. Many issues should be considered when costs are calculated, including the method used to calculate costs, whether costs and benefits were discounted, and whether all relevant costs are included. The length of the study period, or time horizon, should be considered, particularly for interventions such as high-dose chemotherapy with stem cell rescue where most of the costs are accrued “up front” but the benefits are experienced over a lifetime. Although charges and costs are often used interchangeably, they are clearly not the same.8 Charges are inflated from actual cost and are not comparable among providers. They are based on other factors such as accounting methodology, payer mix, and bad debt and are designed to maximize revenues. Charges can be used as a proxy for costs when all patients are treated in the same institution by the same group of physicians and when a uniform billing system is used. Actual charges should not be used as a proxy for costs in multicenter trials because charges for the same resource vary widely among institutions.
Most published economic analyses are conducted from either a provider or payer perspective. A payer’s cost is the amount paid to the provider (eg, hospital, physician) for providing the service. That amount can vary by payer. For example, a managed care organization may pay a different amount than Medicare pays for the same intervention. Studies conducted from a provider perspective require that the actual cost of providing that service be included. Many institutions, however, either do not know or are unwilling to share their actual costs. Provider costs vary among different regions of the United States and also among different health care systems in the same region. Many studies use the institution’s Medicare cost-to-charge ratio to estimate cost. Measurement of the actual cost of physician services can be difficult; how is the actual cost of a physician’s time calculated in an academic medical center where the physician spends time in patient care, research, and teaching? In addition, physicians in private practice also must include overhead expenses into their actual costs.
Several different methods can be used to calculate cost. For studies analyzed from a provider perspective, the institution’s Medicare cost-to-charge ratio is commonly used. Alternatively, one can use a cost accounting method to calculate provider cost. The institution’s cost-to-charge ratio is based on a number of factors such as the utilization rate of equipment used for a specific procedure, the payer mix, and reimbursement policies for that procedure. Some payers limit treatment to selected centers (“centers of excellence”) to decrease costs and to ensure quality. As centers treat more patients, the utilization rate of equipment increases. Thus, these fixed costs are spread out over a larger number of patients, which increases the efficiency of those centers. In addition, allocation of overhead varies from hospital to hospital and may not be indicative of actual resource use.
Two methods are generally used to calculate costs for studies analyzed from a payer perspective. One widely used method is to collect resource units (hospital days, ICU days, etc) and convert them to costs by multiplying each unit by the amount reimbursed by a payer. When the payer is Medicare, data can be obtained from the Health Care Financing Administration (ie, MEDPAR). For nongovernment payers, data can be obtained from the payers themselves, from providers, or from health care information companies. Another method is to use the actual amount reimbursed (based on bills), which can vary depending on the payer.
The study should include all relevant costs appropriate for that specific perspective. Studies analyzed from a hospital or health-system perspective often do not include the cost of physician visits or outpatient care provided after patients are discharged from the treatment center. When not all costs are included, the impact of these omissions on the results of the study should be considered.
Once costs have been determined, it may be necessary to adjust costs and benefits to present value — a procedure referred to as discounting. Costs and benefits need to be discounted if the time horizon of the study is longer than one year. All values must be in the same time period to compare alternatives. This incorporates the economic concept of time preference. Briefly, this concept states that, even in a world with zero inflation and no bank interest, most individuals would prefer to receive a benefit earlier or to incur a cost later because it gives the individual more options. If the costs or benefits are incurred or accrued more than one year in the future, then they need to be adjusted to present value. Various methods can be used for this adjustment, including the institution’s yearly charge inflation rate, rate of inflation as estimated by the Consumer Price Index for Hospitalization Costs, or Consumer Price Indices for Medical Care. Many studies use a discount rate of 5%, although the recently published Public Health Service guidelines recommend that a discount rate of 3% be used.7
Study Types
An understanding of the different types of economic analyses is important because many studies do not correctly use economic terms.9
Cost-Minimization Analysis
The simplest form of economic analysis is the cost-minimization analysis. In this type of study, costs are expressed in monetary units (eg, dollars), and patient outcome is assumed to be the same in both groups. Thus, a cost-minimization analysis is actually a special form of cost-effectiveness analysis where the consequences of the alternatives being compared are equivalent. The objective of this type of analysis is to identify the least expensive alternative.
Cost-Effectiveness Analysis
In a cost-effectiveness analysis, costs are expressed in the numerator in monetary units (eg, dollars), and effectiveness is expressed in the denominator in some unit of effectiveness. The units are usually the same as those clinical outcomes used to measure effectiveness in clinical trials or practice. When comparing two or more alternative interventions, the analyst will select a common clinical outcome.
A disadvantage in a cost-effectiveness analysis is that a comparison of results is difficult when effectiveness is expressed in different units. As a result, medical interventions used to treat different diseases often cannot be compared with each other when decision-makers are trying to allocate resources. This can be particularly problematic when the interventions do not prolong life. When the intervention prolongs life, the most appropriate measure is life-years gained or saved. For example, when comparing two alternative cancer therapies, the difference in survival between the two therapies is often the focus of interest. In that situation, investigators involved in the economic evaluation determine the differences in average cost and survival (average number of life-years gained or saved) between the two interventions. The differences in cost and survival between the two interventions is expressed as a cost-effectiveness ratio, with the difference in cost in the numerator and the difference in survival in the denominator.
Health care decision-makers can use cost-effectiveness analyses to compare different interventions to determine which intervention will result in the most life-years gained for a given dollar value. However, even this approach has its limitations because it does not incorporate all aspects that may be important to the physician and the patient such as utility (ie, patient preference).
Cost-Utility Analysis
Cost-utility analysis is a specific type of cost-effectiveness analysis in which utility is measured and the units of effectiveness are quality-adjusted life-years (QALYs). The major advantage of using QALY as an outcome measure is that it incorporates changes in both quantity (mortality) and quality (morbidity) of life. With this type of analysis, new therapies that greatly reduce morbidity can increase the number of QALYs even without an increase in survival time. The major disadvantage of cost-utility analyses is that utility data are not usually collected in clinical trials because of the additional costs of the data collection and the complex nature of the methods used in utility assessments.
Utility scores measure the strength of a patient’s preference for a given health state or outcome.10,11 Although values, preferences, and utilities are terms that are often used interchangeably, values reflect preferences without risk (or uncertainty), while utilities reflect preferences with risk. The utility approach assigns numerical values on a scale from 0 (death) to 1 (optimal or “perfect” health). It provides a single number that summarizes all of health-related quality of life; some researchers have described utility as a global measure of health-related quality.
Several techniques can be used in utility assessment. Two techniques derived from utility theory are standard gamble and time tradeoff. Because of their complexity, some researchers prefer to use rating scales and multi-attribute techniques to measure patient preferences. Examples of generic preference-based approaches include the Health Utilities Index, Quality of Well-Being Scale, and Disability/Distress Index. Utility approaches are particularly useful in pharmacoeconomic studies because they provide a single summary score of the net change in health-related quality of life — the gains from the positive effects of treatment minus the burden of adverse effects.
Cost-utility analysis is a valuable technique to evaluate new chemotherapeutic regimens that offer some treatment benefit but do not prolong survival in comparison with other therapeutic options. This type of analysis is particularly important with cancer therapies because they are often associated with potentially serious or intolerable adverse effects. Cost-utility analysis is also attractive because it is similar to the approach that many oncologists use when discussing treatment options with their patients. Tradeoffs between the potential benefits of treatment vs the burdens of treatment-related adverse effects are always considered by both the patient and oncologist in decisions concerning treatment.
Cost-Benefit Analysis
In a cost-benefit analysis, both cost and benefits are expressed in the same units, usually monetary units (eg, dollars). In a cost-benefit analysis, all health benefits such as disability days avoided, life-years gained, and medical complications avoided would be translated into monetary units. While theoretically attractive, it is often difficult to determine the cost of health benefits in a cost-benefit analysis. For example, what dollar value is assigned to a life-year gained for a homeless person or a homemaker? This type of analysis is therefore not widely used in the economic analysis of drugs or technology.
Interpretation of Pharmacoeconomic Studies
Interventions do not have to be cost saving (ie, reduce health care cost) to be cost effective. Most medical interventions that are of benefit will increase cost. When an intervention is considered to be cost effective, it implies that the therapeutic benefit of that intervention is worth the cost.
Since economic analyses are often used to assist decision-makers in making policy decisions concerning adoption of that technology in a population, there must be some consensus as to what constitutes a “cost-effective intervention.” In the United States, interventions that prolong life and have a cost-effectiveness ratio in the range of ,000 per life year gained are generally considered to be cost effective. This value of ,000 is considered by many experts as a societal benchmark because it represents the additional cost of dialysis (covered by Medicare) compared with no treatment in patients with end-stage renal disease.
Pharmacoeconomic studies must be critically analyzed because of the nature of economic analyses and because most studies are funded by the pharmaceutical industry. Table 2 shows a checklist that can be used to assess economic evaluations. Most economic evaluations use data from multiple sources, require that many assumptions be made, and use some modeling. As a result, investigators may influence the study design, data sources, or underlying assumptions in order to achieve results that are positive for the sponsor’s product.12 Because decision-makers often lack the necessary knowledge and background to critically analyze pharmacoeconomic studies, the results of studies that are scientifically flawed or biased are sometimes used to make decisions or policies. Because of the perceptions of bias, some journals have specific policies for publication of pharmacoeconomic studies.13
Table 2. — Checklist for Assessing Economic Evaluations
1. Was a well-defined question posed in answerable form?
2. Was a comprehensive description of the competing alternatives given (ie, can you tell who did what to whom, where, and how often)?
3. Was the effectiveness of the programs or services established?
4. Were all the important and relevant costs and consequences for each alternative identified?
5. Were costs and consequences measured accurately in appropriate physical units (eg, hours of nursing time, number of physician visits, lost work-days, gained life-years)?
6. Were costs and consequences valued credibly?
7. Were costs and consequences adjusted for differential timing?
8. Was an incremental analysis of costs and consequences of alternatives performed?
9. Was allowance made for uncertainty in the estimates of costs and consequences?
10. Did the presentation and discussion of study results include all issues of concern to users?
Adapted from Drummond et al.5
Economic analyses usually compare two or more interventions. In many analyses, the investigators select the “comparator” and make assumptions concerning clinical practices. The comparator and the assumptions in the study must be carefully evaluated. For example, treatment with a new anticancer drug may be reported as cost effective when compared with best supportive care. In the United States, however, best supportive care is not usually the community standard because most patients expect or demand some form of therapy. The most appropriate comparator to use in most analyses is another anticancer drug or drug regimen. Similarly, it is important to carefully evaluate other assumptions in the analysis, such as drug dose, dose schedule, duration of infusion, and use of supportive care drugs (eg, antiemetics and growth factors).
For pharmacoeconomic studies that use economic modeling, it is important not only to ensure that the study includes a sensitivity analysis, but also to carefully evaluate that analysis. A sensitivity analysis tests the robustness of the results by modifying the assumptions in various scenarios. Sensitivity analysis allows the analyst to ask a variety of “what if” questions, which is important for economic analyses due to the many assumptions that often have to be made. It identifies the variables that drive the analysis. More confidence is given to a conclusion that is “robust” when subjected to different scenarios.
For economic analyses of new drugs, the acquisition cost of the new drug can be varied in the sensitivity analysis. Since the acquisition cost varies considerably, many pharmacoeconomic studies use the average wholesale price, which is usually higher than the actual acquisition cost. If the drug is investigational, the analyst can evaluate the effect of different acquisition costs on the results.
Sensitivity analysis also allows the analyst to determine the cost-effectiveness of a new drug or intervention in different subsets of patients. Health care decision-makers use this type of analysis to determine which patients should receive the new drug or intervention.
Economic Evaluation of Cancer Treatment
Clinical oncology researchers and the FDA have traditionally demanded objective evidence of antitumor response for new cancer therapies. We often assume that cancer patients have the same preferences as the health care professionals caring for them — that they value cure more highly than prolonged survival and value prolonged survival more highly than tumor shrinkage (Figure). Even if we assume that cancer patients would value prolonged survival over tumor shrinkage, we do not know how much more they would value one outcome over another. Although relief of symptoms clearly has a beneficial impact on a patient’s health-related quality of life, we do not know how patients would value relief of symptoms as a therapeutic goal as compared with more objective endpoints, such as tumor shrinkage or prolonged survival. In one study conducted in the United Kingdom, many cancer patients were willing to accept the adverse effects associated with an intensive chemotherapy regimen for the potential benefit of relief of symptoms.14 In contrast, only a small percentage of the individuals without cancer (control group), oncology nurses, general practitioners, or oncology physicians were willing to accept that treatment under the identical scenario. We also do not know what factors influence those preferences. For example, we expect that the severity of the treatment-related toxicities would influence cancer patient’s preferences for a specific therapy. Similarly, we expect that the magnitude of the treatment benefit, such as the degree of tumor shrinkage or the duration of the survival benefit, would influence a patient’s preferences.
Cost-Minimization Analyses
Cost-minimization analyses are useful when a drug reduces the risk of a clinical event associated with significant resource utilization, such as febrile neutropenia. The additional cost are the costs of the more expensive drug (or drug regimen), drug administration, drug monitoring, adverse effects, etc, and the benefits are the “downstream” cost savings (sometimes referred to as costs offsets) associated with fewer clinical events.
Cost-minimization analyses have been conducted to evaluate the economic benefit of filgrastim-mobilized peripheral-blood progenitor-cell (PBPC) transplantation over autologous bone marrow transplantation (ABMT). These studies show that the high initial cost of growth factors for PBPC mobilization are more than offset by the “downstream” cost savings that result from shorter hospital stay and decreased use of health care resources such as drugs, blood products, physician visits, hyperalimentation, and laboratory and diagnostic tests.
Several clinical trials have reported that hematopoietic recovery, particularly platelet recovery, is more rapid in patients who receive PBPC transplants than in those who have undergone ABMT.15,16 A concurrent economic analysis was performed prospectively as part of one of these studies.17 Resource utilization data were converted to costs based on the cost of each resource unit at an academic medical center in the United States. The analysis divided treatment into three phases: (1) stem cell collection, (2) high-dose chemotherapy (HDC) administration, and (3) recovery until discharge. The total cost included all direct medical costs of HDC, beginning with the cost of stem cell collection and continuing until patients were discharged after the initial hospital stay. Overall, the total cost of HDC was ,000 less in the PBPC group than in the ABMT group. Most of the cost savings occurred during the hospitalization phase (,740 less in the PBPC group), which was primarily related to the more rapid hematologic recovery in the PBPC arm. Furthermore, a shorter hospital course resulted in savings due to decreased use of drugs, blood products, physician visits, hyperalimentation, and laboratory and diagnostic tests.
Cost-Effectiveness Analyses
Cost-effectiveness analyses are useful in evaluating various therapeutic modalities that prolong survival in patients with cancer (Table 3). In the treatment of breast cancer, cost-effectiveness analyses have evaluated the role of adjuvant therapy in various subgroups of women and the role of HDC in women with metastatic disease.
Table 3. — Cost-Effectiveness of Cancer Treatment4,18-22
Intervention
Incremental CE Ratio*
Autologous bone marrow transplantation vs standard chemotherapy for limited metastatic breast cancer
116,000
Adjuvant tamoxifen for early-stage breast cancer (premenopausal ER- woman)
57,000-214,000
Adjuvant chemotherapy for early-stage breast cancer (75-year-old woman)
44,000
Adjuvant interferon alfa-2b for high-risk malignant melanoma
32,600
Autologous bone marrow transplantation vs salvage chemotherapy for Hodgkin’s disease (second relapse only)
26,200
Paclitaxel + cisplatin vs cyclophosphamide + cisplatin for advanced ovarian cancer
21,222
Vinorelbine + cisplatin vs vindesine + cisplatin for non-small cell lung cancer
15,500
Adjuvant chemotherapy vs no treatment for node-negative, early-stage breast cancer (45-year-old woman)
15,400
Adjuvant chemotherapy vs no treatment for early-stage breast cancer (45-year-old woman)
4,900
* Cost-effectiveness (CE) ratio is expressed as dollars (US) per life year gained or quality-adjusted life year.
In 1991, Hillner and Smith18 evaluated the cost effectiveness of adjuvant chemotherapy in women with node-negative breast cancer. The analysis was initiated based on a Clinical Alert in 1988 by the NCI that stated that “chemotherapy can have a meaningful impact on the natural history of node-negative breast cancer patients.” This statement was interpreted by many clinicians at the time as a recommendation for adjuvant therapy in these women. Implementation of this approach was estimated to cost 8 million for the entire group of such patients in the United States. Using the best data available in 1989, the investigators developed a decision analytic model that incorporated the natural history of node-negative breast cancer, effect and toxicity of chemotherapy, and costs of treatment. In the hypothetical cohort, the patient was either a 45-year-old woman or a 60-year-old woman who had undergone surgery for stage I or II breast cancer that was node negative and estrogen-receptor negative. Using a five-year time horizon, the authors estimated that the cost-effectiveness ratio for adjuvant chemotherapy was ,400 per QALY in the 45-year-old cohort and ,800 per QALY in the 60-year-old cohort.
HDC with autologous hematopoietic stem cell rescue has become a widely utilized treatment option for many women with breast cancer and has been associated with increased long-term survival. Unfortunately, this procedure is expensive with estimated charges ranging between ,000 and 0,000 for ABMT. As a result, insurers are sometimes reluctant to approve payment for HDC, often claiming that the therapy is experimental. In an effort to assist policy-makers with their decision to cover the cost of HDC, Hillner and colleagues19 published a cost-effectiveness analysis. The researchers developed a decision analysis model that compared HDC with ABMT vs standard-dose chemotherapy in an attempt to determine the optimal approach for treatment of early metastatic breast cancer and the associated cost effectiveness. The cost effectiveness of HDC with ABMT depends on the magnitude of the difference in survival. If the difference is small (eg, only a few months), HDC is not likely to be cost effective. However, if the difference is large and if there is evidence of a survival plateau (which may indicate that some patients have been cured), HDC is likely to be cost effective and may even be considered the treatment of choice. The hypothetical cohort in the analysis was a 45-year-old patient with stage IV breast cancer. She was unresponsive to hormonal therapy and had no bone marrow involvement or comorbidities. The cost of HDC was estimated to be more than ,000 higher than that of standard chemotherapy (,700 vs ,100). On the basis of a review of the medical literature, the authors concluded that the average survival benefit with HDC was 6.0 months (5-year time horizon). The incremental cost-effectiveness ratio of HDC was 5,800 per life-year gained (5-year time horizon, costs and benefits discounted at 5%). The model was sensitive to assumptions about long-term survival. When a survival tail was assumed (patients who were free of disease at 5 years would have a normal life expectancy), the incremental cost-effectiveness ratio decreased to ,600 per life-year gained.
The costs of HDC in this analysis were estimated from charges for a small number of patients treated at their medical center in 1990, before hematopoietic growth factors were commercially available and PBPCs were widely used. They also analyzed how the cost-effectiveness ratio would change with routine administration of hematopoietic growth factors and PBPC transplantation. For this analysis, the researchers made three assumptions: the duration of hospitalization would decrease from 40 to 30 days, the total cost of HDC would decrease to ,000, and the treatment-related mortality rate would decrease to 3%. It is important to note that with the routine use of growth factors and PBPCs, all three assumptions are true today. With these assumptions considered, the incremental cost-effectiveness ratio would decrease from 5,800 to ,700 per life-year gained, even without changes in the average survival benefit.
Cost-effectiveness analyses can also determine the value of an intervention when long-term survival or cure is not an anticipated outcome (Table 3). Examples of these interventions include vinorelbine in non-small-cell lung cancer,20 paclitaxel and cisplatin in recurrent epithelial ovarian carcinoma,21 and adjuvant interferon alfa-2b in high-risk malignant melanoma.22
Cost-Utility Analyses
Although cost-utility analyses are valuable techniques to evaluate new chemotherapeutic regimens, few such analyses have been published. Hutton et al23 recently reported a cost-utility analysis of taxanes in anthracycline-resistant metastatic breast cancer. In the hypothetical cohort, the patient had failed to respond to adjuvant therapy and had progressed after a median of six months following salvage therapy with an anthracycline-based regimen such as cyclophosphamide, doxorubicin, and fluorouracil. The authors used a decision analytic model to evaluate the pharmacoeconomics of docetaxel vs paclitaxel in patients with anthracycline-resistant recurrent metastatic breast cancer. Costs and practices were based on those in the United Kingdom. Utility scores were obtained from surveys of more than 100 oncology nurses who acted as proxies for the patients in five different countries. Table 4 shows the utility scores for the different health states. Although the cost of docetaxel therapy was slightly higher than that of paclitaxel therapy, docetaxel treatment was associated with a gain of 0.0905 QALY per patient, which is equivalent to 33 days of perfect health. The incremental cost-utility ratio of docetaxel as compared with paclitaxel was estimated to be less than ,000 (in US dollars, after conversion from British pounds) per QALY.
Table 4. — Utility Scores of Core Health States in Metastatic Breast Cancer
Health State
Utilities (International)
Utilities (UK only)
Partial response
0.81
0.84
Partial response plus severe peripheral edema
0.75
0.78
Stable disease
0.62
0.62
Before commencement of second line therapy
0.59
0.56
Partial response plus severe peripheral neuropathy
0.53
0.62
Progressive disease
0.41
0.33
Sepsis
0.20
0.16
Terminal disease
0.16
0.13
From Hutton J, Brown R, Borrowitz M, et al. A new decision model for cost-utility comparisons of chemotherapy in recurrent metastatic breast cancer. PharmacoEconomics. 1996;9(suppl 2):8-22. Reprinted with permission.
Conclusions
Pharmacoeconomics is a tool to determine the value of drugs. Although the results of economic analyses are being increasingly used by decision-makers, many issues concerning study design, data collection, and other research methods are controversial, and most health-care professionals have had little or no formal training in economic analysis. In addition, there is concern about the potential for bias in the conduct of economic studies. Economic analyses of drugs should be carefully and critically evaluated to determine the relevance of the study to a specific situation (Table 2).
Dr. Yee has received honoraria from Amgen, Inc, Rhône-Poulenc Rorer, S.A., and Bristol-Myers Squibb Co.
References
1. Brown ML. The national economic burden of cancer: an update. J Natl Cancer Inst. 1990;82:1811-1814.
2. Market evolution continues: strategies for effective change. San Diego, Calif, October 28-29, 1996. University Hospital Consortium.
3. American Society of Clinical Oncology. Outcomes of cancer treatment for technology assessment and cancer treatment guidelines. J Clin Oncol. 1996;14:671-679.
4. Smith TJ, Hillner BE, Desch CE. Efficacy and cost-effectiveness of cancer treatment: rational allocation of resources based on decision analysis. J Natl Cancer Inst. 1993;85:1460-1474.
5. Drummond MF, O’Brien B, Stoddard GL, et al. Methods for the Economic Evaluation of Health Care Programmes. 2nd ed. New York, NY: Oxford University Press; 1997.
6. Bootman JL, Townsend RJ, McGhan WF, eds. Principles of Pharmacoeconomics. 2nd ed. Cincinnati, Oh: Harvey Whitney Books Co; 1996.
7. Gold MR, Siegel JE, Russell LB. Cost-Effectiveness in Health and Medicine. New York, NY: Oxford University Press; 1996.
8. Finkler SA. The distinction between cost and charges. Ann Intern Med. 1982;96:102-109.
9. Doubilet P, Weinstein MC, McNeil BJ. Use and misuse of the term “cost effective” in medicine. N Engl J Med. 1986;314:253-256.
10. Torrance GW. Measurements of health state utilities for economic appraisal: a review. J Health Econ. 1986;5:1-30.
11. Torrance GW. Utility approach to measuring health-related quality of life. J Chron Dis. 1987;40:593-603.
12. Hillman AL, Eisenberg JM, Pauly MV, et al. Avoiding bias in the conduct and reporting of cost-effectiveness research sponsored by pharmaceutical companies. N Engl J Med. 1991;324:1362-1365.
13. Kassirer JP, Angell M. The journal’s policy on cost-effectiveness analyses. N Engl J Med. 1994;331:669-670.
14. Slevin ML, Stubbs L, Plant HJ, et al. Attitudes to chemotherapy: comparing views of patients with cancer with those of doctors, nurses, and general public. BMJ. 1990;300:1458-1460.
15. Schmitz N, Linch DC, Dreger P, et al. Randomised trial of filgrastim-mobilised peripheral blood progenitor cell transplantation versus autologous bone-marrow transplantation in lymphoma patients. Lancet. 1996;347:353-357.
16. Hartmann O, Corroller AG, Blaise D, et al. Peripheral blood stem cell and bone marrow transplantation for solid tumors and lymphomas: hematologic recovery and costs. A randomized, controlled trial. Ann Intern Med. 1997;126:600-607.
17. Smith TJ, Hillner BE, Schmitz N, et al. Economic analysis of a randomized clinical trial to compare filgrastim-mobilized peripheral-blood progenitor-cell transplantation and autologous bone marrow transplantation in patients with Hodgkin’s and non-Hodgkin’s lymphoma. J Clin Oncol. 1997;15:5-10.
18. Hillner BE, Smith TJ. Efficacy and cost effectiveness of adjuvant chemotherapy in women with node-negative breast cancer. A decision-analysis model. N Engl J Med. 1991;324:160-168.
19. Hillner BE, Smith TJ, Desch CE. Efficacy and cost-effectiveness of autologous bone marrow transplantation in metastatic breast cancer. Estimates using decision analysis while awaiting clinical trial results. JAMA. 1992;267:2055-2061.
20. Smith TJ, Hillner BE, Neighbors DM, et al. Economic evaluation of a randomized clinical trial comparing vinorelbine, vinorelbine plus cisplatin, and vindesine plus cisplatin for non-small-cell lung cancer. J Clin Oncol. 1995;13:2166-2173.
21. McGuire W, Neugut AI, Arikian S, et al. Analysis of the cost-effectiveness of paclitaxel as alternative combination therapy for advanced ovarian cancer. J Clin Oncol. 1997;15:640-645.
22. Hillner BE, Kirkwood JM, Atkins MB, et al. Economic analysis of adjuvant interferon alfa-2b in high-risk melanoma based on projections from Eastern Cooperative Oncology Group 1684. J Clin Oncol. 1997;15:2351-2358.
23. Hutton J, Brown R, Borrowitz M, et al. A new decision model for cost-utility comparisons of chemotherapy in recurrent metastatic breast cancer. PharmacoEconomics. 1996;9(suppl 2):8-22
From Shands Hospital and the University of Florida College of Pharmacy, Gainesville, Fla. Dr Yee is currently at the University of Nebraska Medical Center, Omaha, Neb.
Address reprint requests to Gary C. Yee, PharmD, FCCP, at the College of Pharmacy, University of Nebraska Medical Center, 600 South 42nd St, Omaha, NE 68198.
Back to Cancer Control Journal Volume 5 Number 5
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