Cost-Utility Analysis and Trastuzumab

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Of the paradigms that govern the treatment of breast cancer that is most accepted is that of the treatment of metastatic breast cancer that is HER-2 positive. For these patients, chemotherapy with trastuzumab is the gold standard. Once women progress, chemotherapy is changed but trastuzumab is continued. One clinical trial supports the continuation of trastuzumab beyond disease progression. The Breast International Group (BIG) 03-05 study showed that trastuzumab with the agent capecitabine significantly prolonged both progression-free survival (8 vs. 6 months) and overall survival (26 vs. 20 months) when compared to capecitabine alone after women had progressed on a first-line treatment of chemotherapy with trastuzumab.

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What has become clearer in oncology is that even in the presence of such data, coupled with the changing landscape of treatment in breast cancer (in this case, the use of trastuzumab after surgery with curative intent), is the question of whether any health care system can support the use of expensive biologic agents where cure is not achieved. The means to examine such questions comes in cost-effectiveness analyses, which take into account direct medical costs (ie, chemotherapy treatments, treatment of adverse effects of treatment, laboratory and radiology studies) and the disease outcomes (survival and death). The perspective of whether or not something is cost effective is expressed in the Incremental Cost-Effectiveness ratio (ICER) which gives the "cost per quality-adjusted life year gained". While the threshold of "what is an acceptable ICER" can be debated, a reasonable estimate of costs in the US is that associated with a chronic medical condition, such as hemodialysis due to renal failure, in which case the ICER is around $129,000/QALY.

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Taking the data from the BIG 03-05 study, a group from Switzerland did such an analysis on the use of trastuzumab. Factoring clinical data and estimates of cost to the Swiss healthcare system, they concluded that the addition of bevacizumab to capecitabine cost an additional 34,000 Euros ($43,200 USD) to gain 0.35 quality adusted life years (QALY). This translates into an ICER of 98,330 Euros, or $124,958 USD/QALY.

The importance of such an analysis comes at a time of great change in our health care system. With the passage of health care reform, the public should demand to understand costs in perspective. As medical care costs continue to climb, reviewing treatments (both established and new) in a standardized way will help to understand how much the gains are costing society. In this case it is reassuring to know that treating HER-2 positive metastatic breast cancer falls within the range of what society normally would consider as cost-effective. It provides assurance to me as an oncologist that the daily gains I witness in the lives of women living with metastatic breast cancer are reflected in what society considers cost-effective as well.

References:

1. von Minckwitz G, et al. J Clin Oncol 2009;27:1999-2006.

2. Lee CP, et al. Value in Health 2008;12:80-87.

3. Matter-Walstra KW, et al. Ann Oncol 2010; E-pub 5/5/2010.