Conflict of interest in economic analyses of aromatase inhibitors in breast cancer: a systematic review

Abstract

To determine whether authors conducting economic analyses of aromatase inhibitors in breast cancer are less likely to reach unfavorable conclusions if the economic study is sponsored by the manufacturer of the drug. Articles reporting the economic analyses of aromatase inhibitors in breast cancer were selected from PubMed in May 2009. Information was collected on the types of analysis, the qualitative conclusion, the quantitative results, and the funding sources. Fisher's exact test was conducted to compare the frequency of unfavorable conclusions based on study sponsorship. Thirty-two eligible articles were identified. Twenty-six were funded by pharmaceutical companies, and 4 were funded by non-pharmaceutical companies. Two studies did not report a funding source. Twenty-one studies evaluated aromatase inhibitors in the adjuvant setting, while 11 studies examined their use in advanced breast cancer. Twenty-two studies evaluated one type aromatase inhibitor, while 10 compared multiple types of aromatase inhibitors. Only one of the 26 (4%) pharmaceutical company-sponsored studies reported unfavorable cost-effectiveness of an aromatase inhibitor, which was a competitor's product, whereas two of four (50%) non-pharmaceutical company-sponsored studies concluded aromatase inhibitors are not cost-effective in certain clinical scenarios (P < 0.05). Seven pharmaceutical company-sponsored studies conducted a comparison among several aromatase inhibitors; all 7 studies reported favorable conclusions for the sponsoring company's products. The majority of economic analyses of aromatase inhibitors in breast cancer are sponsored by pharmaceuticals. Economic evaluations of aromatase inhibitors in breast cancer that are funded by a pharmaceutical company are less likely to reach unfavorable conclusions about the sponsor's product.

Reviewing the Cost-Effectiveness of Endocrine Early Breast Cancer Therapies: Influence of Differences in Modeling Methods on Outcomes

“…These outcomes confirm the conclusions made by Jang et al [51] that economic evaluations funded by a pharmaceutical company are less likely to reach unfavorable conclusions, but it must be kept in mind that in this case it only occurred in two analyses and that nonpharmaceutical companysponsored studies also calculated high ICERs.…”

A Systematic Review and Methodological Evaluation of Published Cost-Effectiveness Analyses of Aromatase Inhibitors versus Tamoxifen in Early Stage Breast Cancer

“…Compared to other systematic reviews we employ no language restrictions. [51], [52] We also systematically assess important potential sources of bias in CEA. Our analysis also compares predictions of model-based CEAs for AIs to clinical data.…”

“…Jang et al demonstrated that industry sponsored CEAs were significantly more likely than CEAs conducted by independent academic centres to reach favourable conclusions about the cost-effectiveness of AIs. [52] It was beyond the scope of our analysis to quantify the impact of industry sponsorship on methodological choices and CEA conclusions, even though association between industry-sponsorship and favourable CEA findings is well established. [62]–[64] We focused only on AIs in the first-line setting, and thus had limited statistical power to detect differences.…”

Industry involvement and baseline assumptions of cost-effectiveness analyses: diagnostic accuracy of the Papanicolaou test

“…8 Their more favourable results are obtained mostly by comparing the industry-sponsored medication against inferior comparators (e.g., placebo or a "straw-man" medication with little or no effectiveness). 8 Similarly, several studies suggest that company-sponsored cost-effectiveness analyses are more likely to report favourable qualitative conclusions [9][10][11][12][13] and one systematic review concluded that such studies reported favourable incremental cost-effectiveness ratios 1 compared with nonsponsored studies. For example, in an empirical evaluation of 495 cost-effectiveness analyses, industry sponsorship increased threefold the odds of an incremental cost-effectiveness ratio below $50 000 per quality-adjusted life year.…”