Cost-effectiveness of exemestane versus tamoxifen as adjuvant therapy for early-stage breast cancer after 2-3 years treatment with tamoxifen in Sweden

Economic Evaluation of Fulvestrant 500 mg Compared to Generic Aromatase Inhibitors in Patients with Advanced Breast Cancer in Sweden

OBJECTIVES

In Sweden, breast cancer (BC) represents 30% of newly diagnosed cancers and is the most common cancer in women. For hormone-dependent BC, endocrine therapies varying in efficacy and price are available. The aim of this study is to assess the cost effectiveness of fulvestrant 500 mg as a second-line hormonal therapy for postmenopausal women with estrogen receptor-positive metastatic or locally advanced BC versus letrozole, anastrozole, and exemestane in Sweden.

METHODS

A three-state (pre-progression, post-progression, and death) partitioned-survival model was used to estimate progression-free (PFS) and overall survival (OS) by extrapolating trial results beyond the trial period to capture costs and benefits over a lifetime perspective. The comparative effectiveness was sourced from a network meta-analysis. The evaluation was conducted from a Swedish national payer perspective; costs, resource use, and quality of life were based on published sources and expert opinion.

RESULTS

Compared to anastrozole, letrozole, and exemestane the incremental cost-effectiveness ratios (ICERs) were €33,808, €33,883, and €49,225 per QALY with incremental costs of €13,283, €14,986, and €13,862, and incremental QALYs of 0.393, 0.442, and 0.282, respectively. Incremental cost per life-year (LY) gained €21,312 (incremental LY of 0.623), €20,338 (incremental LY of 0.737), and €27,854 (incremental LY of 0.498) for respective comparators. Applying the upper and lower credible intervals for PFS/OS from the meta-analysis had the greatest effect on the ICER in the sensitivity analysis. The results were relatively stable when varying other parameters.

CONCLUSIONS

Our results indicate that fulvestrant 500 mg may be a cost-effective alternative to aromatase inhibitors at a threshold of €100,000/QALY.

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.

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.

Cost-effectiveness analysis review of exemestane in the treatment of primary and advanced breast cancer

INTRODUCTION

Exemestane was approved in 2005 for adjuvant treatment of breast cancer. In this study, we aimed to assess whether it is cost-effective in comparison to available alternatives.

MATERIAL AND METHODS

To evaluate the efficacy of exemestane, a systematic review was conducted by searching electronic databases. The outcomes of interest were "clinical benefit", "overall response" and "disease-free survival rate". To evaluate the cost of treatments, costs of both domestic generic and imported brand medicines were taken into account, and the incremental cost-effectiveness ratio (ICER) was calculated for each comparison.

RESULTS

Regarding primary breast cancer, based upon available evidence, exemestane could not be considered as a cost-effective medicine either in generic or brand form compared with placebo (ICER: 119,100 and 215,525), with tamoxifen after 2-3 years of therapy (ICER: 35,150 and 82,400) and with sequential treatment by tamoxifen and exemestane (dominated because of lower effectiveness and higher cost). In metastatic breast cancer, exemestane was not considered a cost-effective treatment compared with both anastrozole and megestrol acetate (dominated) and was highly cost-effective compared with tamoxifen (ICERs: 2,208 and 4,326 dollars per one more patient with an overall response for generic and brand medicines) although even in this case it was not cost-effective in terms of the 1-year survival rates (dominated).

CONCLUSIONS

Regarding current evidence and related costs in terms of Iranian pharmaceutical market prices, exemestane could not be considered a cost-effective treatment in primary and advanced breast cancer compared with available alternatives. However, more evidence is still needed for more certain decisions.

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.

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.

Aromatase inhibitors versus tamoxifen as adjuvant hormonal therapy for oestrogen sensitive early breast cancer in post-menopausal women: meta-analyses of monotherapy, sequenced therapy and extended therapy

Adjuvant tamoxifen reduces relapses and prolongs survival in patients with oestrogen sensitive breast cancer. Development of resistance is however common. Tamoxifen can be given for a maximum of five years; although the risk of recurrences remains high after this period. This review examines nine randomised controlled trials including 28,632 women, which studied aromatase inhibitors (AIs) as an alternative to tamoxifen in three treatment settings: monotherapy (instead of tamoxifen), sequenced therapy (tamoxifen is switched to an AI) and extended therapy (following adjuvant tamoxifen). Disease free survival was significantly improved for monotherapy (HR 0.89, [95% CI 0.83-0.96] p = 0.002) and sequenced therapy (HR 0.72, [0.63-0.83] p < 0.00001). There was no difference in overall survival for monotherapy (HR 0.94, [0.82-1.08] p = 0.39) or extended therapy (HR 0.86 [0.79-1.16] p = 0.67). Importantly, overall survival was prolonged for patients who switched from tamoxifen to AI therapy (HR 0.78 95%CI 0.68-0.91, p = 0.001).

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.

Exemestane: a review of its use in postmenopausal women with breast cancer

Exemestane (Aromasin) is an orally active steroidal irreversible inactivator of the aromatase enzyme indicated as an adjuvant treatment in postmenopausal women with estrogen receptor-positive early-stage breast cancer following 2-3 years of adjuvant treatment with tamoxifen, and for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen or other antiestrogen therapy. Exemestane is effective for the treatment of postmenopausal women with early-stage or advanced breast cancer. In early-stage disease, switching to exemestane for 2-3 years after 2-3 years of adjuvant tamoxifen treatment was more effective in prolonging disease-free survival than continuing tamoxifen therapy, although it was not associated with an overall survival benefit, except in those with estrogen receptor-positive or unknown receptor status disease when nodal status, hormone replacement therapy (HRT) and chemotherapy use were adjusted for. Moreover, preliminary data suggest that the efficacy of exemestane is generally no different to that of tamoxifen in the primary adjuvant treatment of early-stage breast cancer, although exemestane may be better in prolonging the time to distant recurrence. In advanced disease, exemestane showed equivalent efficacy to megestrol in patients with disease refractory to tamoxifen and an efficacy not significantly different from that of fulvestrant in those refractory to a nonsteroidal aromatase inhibitor. Available data, some of which are limited, suggest exemestane is also effective in the first-line hormonal treatment of advanced breast cancer in postmenopausal women. Exemestane is generally well tolerated, although the potential bone fracture risk of the drug requires further investigation. Results from directly comparative trials indicating the efficacy, tolerability and bone fracture risk of exemestane relative to third-generation aromatase inhibitors and other agents in both early-stage and advanced disease, as well as the optimal sequence of endocrine therapies, are awaited with interest. In the meantime, switching to exemestane should be considered in postmenopausal women who have received 2-3 years of adjuvant tamoxifen treatment for early-stage breast cancer, and is an emerging treatment option for postmenopausal women with advanced breast cancer refractory to one or more antiestrogen therapies.

Methodological issues in evaluating cost effectiveness of adjuvant aromatase inhibitors in early breast cancer: a need for improved modelling to aid decision making

The optimal adjuvant hormonal strategy in post-menopausal women with early breast cancer is a subject of ongoing debate. Aromatase inhibitors (AIs) have been successfully evaluated in clinical trials that have compared them with a standard treatment of 5 years of tamoxifen. However, several options are available in terms of treatment schedule and selected drug. Systematic reviews of clinical trials and health economic evaluations attempt to contribute to the debate. The objective of this paper is to provide a critical review of existing health economic evaluations with a focus on those parameters and assumptions with the largest impact on final outcomes.A wide range of different inputs and assumptions exist, which make a comparison of results difficult, if not impossible. In particular, the modelling of recurrence rates over longer time horizons than those observed in clinical trials, a cornerstone of health economic modelling, is subject to quite different approaches. The practice of indirect comparison of different AIs without sufficiently acknowledging population differences is also bothersome. A list of key features (related to time horizon, clinical data input, patient subtypes, budget impact and model calibration) that an ideal model should have in order to better assist decision makers in this field is proposed.

Comparative economic analysis of aromatase inhibitors and tamoxifen in the treatment of hormone-dependent breast cancer

Within the past 2 years three separate groups reported marked improvements in relapse-free survival when trastuzumab was added to adjuvant chemotherapy in patients with HER2-overexpressing breast cancer. Notwithstanding the significance of this molecular target, the discovery of the estrogen receptor (ER) may be of even greater importance. Although tamoxifen has long been considered the hormonal therapy of choice for patients with estrogen-responsive breast cancer, accumulating clinical data suggest the new generation of aromatase inhibitors (AIs) is more effective and less toxic. With the availability of new information, guidelines have been updated and reformulated regarding the use of AIs as first-line hormonal therapy in postmenopausal women with ER-positive breast cancer. This paper, a product of the ongoing advances in oncology, incorporates two distinct, yet important, features of oncology; first, clinical concepts related to hormone-dependent breast cancer and second, pharmacoeconomic evaluation of the antiestrogen tamoxifen and the new generation of antiaromatase agents.