Cost-effectiveness of switching to exemestane versus continued tamoxifen as adjuvant therapy for postmenopausal women with primary breast cancer

Cost-utility analyses of drug therapies in breast cancer: a systematic review

The economic evaluation (EE) of health care products has become a necessity. Their quality must be high in order to trust the results and make informed decisions. While cost-utility analyses (CUAs) should be preferred to cost-effectiveness analyses in the oncology area, the quality of breast cancer (BC)-related CUA has been given little attention so far. Thus, firstly, a systematic review of published CUA related to drug therapies for BC, gene expression profiling, and HER2 status testing was performed. Secondly, the quality of selected CUA was assessed and the factors associated with a high-quality CUA identified. The systematic literature search was conducted in PubMed, MEDLINE/EMBASE, and Cochrane to identify published CUA between 2000 and 2014. After screening and data extraction, the quality of each selected CUA was assessed by two independent reviewers, using the checklist proposed by Drummond et al. The analysis of factors associated with a high-quality CUA (defined as a Drummond score ≥7) was performed using a two-step approach. Our systematic review was based on 140 CUAs and showed a wide variety of methodological approaches, including differences in the perspective adopted, the time horizon, measurement of cost and effectiveness, and more specially health-state utility values (HSUVs). The median Drummond score was 7 [range 3-10]. Only one in two of the CUA (n = 74) had a Drummond score ≥7, synonymous of "high quality." The statistically significant predictors of a high-quality CUA were article with "gene expression profiling" topic (p = 0.001), consulting or pharmaceutical company as main location of first author (p = 0.004), and articles with both incremental cost-utility ratio and incremental cost-effectiveness ratio as outcomes of EE (p = 0.02). Our systematic review identified only 140 CUAs published over the past 15 years with one in two of high quality. It showed a wide variety of methodological approaches, especially focused on HSUVs. A critical appraisal of utility values is necessary to better understand one of the main difficulties encountered by authors and propose areas for improvement to increase the quality of CUA. Since the last 5 years, there is a tendency toward an improvement in the quality of these studies, probably coupled with economic context, a better and widely spreading of recommendations and thus appropriation by medical practitioners. That being said, there is an urgent need for mandatory use of European and international recommendations to ensure quality of such approaches and to allow easy comparison.

The value-for-money of adjuvant aromatase inhibitors: time to put the debate to rest?

The adoption of costly treatments in public health care systems, such as exists in Canada, must take into account their “clinical benefit to side effect” profiles and “value for money” in an attempt to maximize health gains within current budget constraints [...]

Economic evaluation of using a genetic test to direct breast cancer chemoprevention in white women with a previous breast biopsy

BACKGROUND

Tamoxifen therapy reduces the risk of breast cancer but increases the risk of serious adverse events including endometrial cancer and thromboembolic events.

OBJECTIVES

The cost effectiveness of using a commercially available breast cancer risk assessment test (BREVAGen™) to inform the decision of which women should undergo chemoprevention by tamoxifen was modeled in a simulated population of women who had undergone biopsies but had no diagnosis of cancer.

METHODS

A continuous time, discrete event, mathematical model was used to simulate a population of white women aged 40-69 years, who were at elevated risk for breast cancer because of a history of benign breast biopsy. Women were assessed for clinical risk of breast cancer using the Gail model and for genetic risk using a panel of seven common single nucleotide polymorphisms. We evaluated the cost effectiveness of using genetic risk together with clinical risk, instead of clinical risk alone, to determine eligibility for 5 years of tamoxifen therapy. In addition to breast cancer, the simulation included health states of endometrial cancer, pulmonary embolism, deep-vein thrombosis, stroke, and cataract. Estimates of costs in 2012 US dollars were based on Medicare reimbursement rates reported in the literature and utilities for modeled health states were calculated as an average of utilities reported in the literature. A 50-year time horizon was used to observe lifetime effects including survival benefits.

RESULTS

For those women at intermediate risk of developing breast cancer (1.2-1.66 % 5-year risk), the incremental cost-effectiveness ratio for the combined genetic and clinical risk assessment strategy over the clinical risk assessment-only strategy was US$47,000, US$44,000, and US$65,000 per quality-adjusted life-year gained, for women aged 40-49, 50-59, and 60-69 years, respectively (assuming a price of US$945 for genetic testing). Results were sensitive to assumptions about patient adherence, utility of life while taking tamoxifen, and cost of genetic testing.

CONCLUSIONS

From the US payer's perspective, the combined genetic and clinical risk assessment strategy may be a moderately cost-effective alternative to using clinical risk alone to guide chemoprevention recommendations for women at intermediate risk of developing breast cancer.

Are the true impacts of adverse events considered in economic models of antineoplastic drugs? A systematic review

BACKGROUND

Antineoplastic drugs for cancer are often associated with adverse events, which influence patients' physical health, quality of life and survival. However, the modelling of adverse events in cost-effectiveness analyses of antineoplastic drugs has not been examined.

AIMS

This article reviews published economic evaluations that include a calculated cost for adverse events of antineoplastic drugs. The aim is to identify how existing models manage four issues specific to antineoplastic drug adverse events: the selection of adverse events for inclusion in models, the influence of dose modifications on drug quantity and survival outcomes, the influence of adverse events on quality of life and the consideration of multiple simultaneous or recurring adverse events.

METHODS

A systematic literature search was conducted using MESH headings and key words in multiple electronic databases, covering the years 1999-2009. Inclusion criteria for eligibility were papers covering a population of adults with solid tumour cancers, the inclusion of at least one adverse event and the resource use and/or costs of adverse event treatment.

RESULTS

From 4,985 citations, 26 eligible articles were identified. Studies were generally of moderate quality and addressed a range of cancers and treatment types. While the four issues specific to antineoplastic drug adverse events were addressed by some studies, no study addressed all of the issues in the same model.

CONCLUSION

This review indicates that current modelling assumptions may restrict our understanding of the true impact of adverse events on cost effectiveness of antineoplastic drugs. This understanding could be improved through consideration of the selection of adverse events, dose modifications, multiple events and quality of life in cost-effectiveness studies.

Reviewing the cost-effectiveness of endocrine early breast cancer therapies: influence of differences in modeling methods on outcomes

OBJECTIVES

The purpose of this systematic review is primarily to identify published cost-effectiveness analyses and cost-utility analyses of endocrine therapies for the treatment of early breast cancer. A secondary objective is to identify whether differences in seven modeling characteristics are related to differences in outcome of these cost-effectiveness and cost-utility analyses.

METHODS

A systematic literature review was conducted to identify peer-reviewed full economic evaluations of endocrine treatments of early breast cancer published in the English language between 2000 and December 2010. Information from these publications was abstracted regarding outcome, quality, and modeling methods.

RESULTS

We identified 20 economic evaluations comprising 5 different endocrine therapeutic strategies, which are all assessed more then once. The incremental cost-effectiveness ratios (ICERs) of the reported outcomes varied widely for identical therapies. For anastrazole compared to tamoxifen, incremental life-years gained even ranged from 0.16 to 0.550 with an ICER ranging from €3,958 to €75,331. Incremental quality-adjusted life-years (QALYs) gained ranged from 0.092 to 0.378 with a cost per QALY gained varying from €3,696 to €120,265. These large differences in outcome were related to different modeling methods, with differences in time horizon and use of a carryover effect as most prominent causes.

CONCLUSION

Despite similar comparators and logical differences due to transferability issues, the outcomes of the included studies varied widely. To increase comparability and transparency of pharmacoeconomic evaluations, standardization of modeling methods for different therapeutic groups/diseases and the availability of a detailed and complete description of the model used in the evaluation is advocated. Recommendations for standardization in modeling treatment strategies in early breast cancer are presented.

Clinical and economic benefits of aromatase inhibitor therapy in early-stage breast cancer

PURPOSE

The clinical and economic benefits of aromatase inhibitor (AI) therapy in early-stage breast cancer are reviewed.

SUMMARY

AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer, as it significantly reduces the risk of disease recurrence and death. Using the currently accepted gold standard for clinical efficacy-improvement in disease-free survival rather than overall survival-exemestane, anastrozole, or letrozole as monotherapy or in sequence with tamoxifen has been found to be superior to tamoxifen monotherapy. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. Of the nonsteroidal AIs, letrozole appears to have the efficacy advantage by demonstrating an early effect on distant recurrence and, subsequently, a potentially significant overall survival benefit, though results of a prospective head-to-head trial of anastrozole and letrozole are not yet available. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence. However, preliminary analyses indicate that the survival benefit appears to be greater with letrozole than with anastrozole. Thus, considering potential survival benefits and cost-effectiveness, letrozole may be preferable to anastrozole in the early adjuvant setting.

CONCLUSION

AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence.

Exemestane in the adjuvant treatment of breast cancer in postmenopausal women

Exemestane is an irreversible inhibitor of the aromatase enzyme, which is a key component in the production of estrogen. The majority of breast cancers are sensitive to the proliferative effects of estrogen. Exemestane is approved for the adjuvant treatment of postmenopausal women with breast cancer after 2 to 3 years of tamoxifen therapy, based on a 32% improvement in disease-free survival compared with 5 years of tamoxifen alone (P < 0.001). Exemestane has also shown clinical benefits as an upfront therapy. The safety profile of exemestane shares some side effects with tamoxifen (hot flashes and arthralgia), but is not associated with an increased risk of endometrial cancer or thromboembolic events. This review will discuss in detail the efficacy and safety of exemestane in early breast cancer.

A Canadian economic analysis of U.S. Oncology Adjuvant Trial 9735

OBJECTIVES

Recent results of the U.S. Oncology Adjuvant Trial 9735 demonstrated significant disease-free survival and overall survival benefits for docetaxel and cyclophosphamide (tc) compared with doxorubicin and cyclophosphamide (ac) in the adjuvant treatment of operable invasive breast cancer. Based on clinical data from the 9735 study, we evaluated the lifetime cost-effectiveness of tc compared with ac from the perspective of the Canadian publicly funded health care system.

METHODS

A Markov model was developed to estimate the incremental cost per quality-adjusted life-year gained and per life-year gained. Monthly survival and risk of disease recurrence up to 7 years were obtained directly from the overall survival and disease-free survival curves in the 9735 study; life-years beyond 7 years were estimated using the average life expectancy of age-matched women in the general Canadian population. Canadian-specific resource utilization and unit costs (in 2008 Canadian dollars) were applied to estimate costs for chemotherapy administration, chemotherapy-related toxicities, recurrence, and adverse events. Health-utility scores and decrements used in the calculation of quality-adjusted life-years were derived from the literature.

RESULTS

The lifetime cost per quality-adjusted life-year gained was $8,251 for tc compared with ac, and the cost per life-year gained was $6,842. The results were robust across a range of sensitivity analyses.

CONCLUSIONS

Cost-effectiveness, combined with efficacy and an acceptable safety profile, support the adoption of tc as an alternative to ac in Canadian clinical practice for the adjuvant treatment of operable early breast cancer.

A prospective cohort study defining utilities using time trade-offs and the Euroqol-5D to assess the impact of cancer-related lymphedema

BACKGROUND

The devastating impact of lymphedema on cancer survivors' quality of life has prompted consideration of several changes in medical and surgical care. Unfortunately, our understanding of the benefits gained from these approaches relative to their cost remains limited. This study was designed to estimate utilities for lymphedema and characterize how utilities differ between subgroups defined by lymphedema etiology and distribution.

METHODS

A consecutive sample of 236 subjects with lymphedema seen at a lymphedema clinic completed both a time trade-off (TTO) exercise and the Euroqol 5D. Responses were adjusted in multivariate regression models for demographic factors, comorbidities, and lymphedema severity/location.

RESULTS

Most participants (167 of 236, 71%) had lymphedema as a consequence of cancer treatment; 123 with breast cancer and upper extremity involvement. Mean TTO utility estimates were consistently higher than Euroqol 5D estimates. Unadjusted TTO (0.85; standard deviation [SD], 0.21) and Euroqol 5D (0.76; SD, 0.18) scores diminished with increasing lymphedema stage and patient body mass index (BMI). Adjusted utility scores were lowest in patients with cancer-related lower extremity lymphedema (TTO=0.82; SD, 0.04 and Euroqol 5D=0.80; SD, 0.03). Breast cancer patients also had lower adjusted Euroqol 5D scores (0.80; SD, 0.02).

CONCLUSIONS

Lymphedema-associated utilities are in the range of 0.80. Lower utilities are observed for patients with higher lymphedema stages, elevated BMI, and cancer-related lymphedema. Greater expenditures for the prevention and treatment of cancer-related lymphedema are warranted.

Cost Effectiveness of Exemestane versus Tamoxifen in Post-Menopausal Women with Early Breast Cancer in Germany

BACKGROUND: Medical studies have shown that switching to exemestane after 2-3 years of adjuvant treatment with tamoxifen is effective when looking at overall survival. No cost effectiveness study of exemestane has been conducted in the German health care context. PATIENTS AND METHODS: To assess the cost effectiveness of switching to exemestane vs. continued tamoxifen therapy for early-stage breast cancer, a Markov model was developed. The model population was set as postmenopausal women who are in remission from early-stage breast cancer. Upon model entry, either a continuing daily therapy with 20 mg tamoxifen or a switch to 25 mg exemestane for the next 2-3 years takes place. The model takes a German health care perspective. RESULTS: The total incremental costs of exemestane on a lifetime basis are 4,195 Euro, resulting in an incremental cost effectiveness ratio of 17,632 Euro per additional quality-adjusted life year (QALY), or 16,857 Euro per life year gained. Incremental costs per disease-free year of survival are 12,851 Euro. Probabilistic sensitivity analyses proved the robustness of these findings. CONCLUSION: Compared to extended tamoxifen therapy, switching to exemestane after 2-3 years turned out to be a cost-effective strategy in adjuvant therapy for early-stage breast cancer in postmenopausal women within the German health care context.