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| |  EBCC: Arimidex (Anastrozole) First-Line Therapy Highly Effective For Advanced Breast Cancer BRUSSELS, BELGIUM -- September 28, 2000 -- Results from two studies released at the second annual European Breast Cancer Conference in Brussels confirm Arimidex® (anastrozole) as a first choice, first-line therapy for postmenopausal women with hormone-receptor positive advanced breast cancer. New data provides physicians with the additional reassurance that using Arimidex first-line does not compromise tamoxifen's efficacy when it is used subsequently as second-line treatment. The study's findings, released just prior to the beginning of National Breast Cancer Awareness Month in Canada, are especially encouraging for women living with the disease. Breast cancer is currently the leading cause of death among Canadian women between the ages of 35 and 55. It is estimated that 19,200 women will develop breast cancer this year in Canada and 5,500 are expected to die from the disease in 2000. A prospective combined analysis of 1021 patients from two randomized, double blind trials of identical design, compared the efficacy and tolerability of Arimidex (1mg daily) with tamoxifen (20mg daily) when used as first-line therapy in postmenopausal women with advanced breast cancer. Primary endpoints were time to progression (TTP), objective response and tolerability. "This study is important not only because it shows that Arimidex should be used as first-line therapy in patients who have receptor positive tumours, but also because it indicates that tamoxifen remains an effective treatment option when given as second line therapy after Arimidex," says Dr. John Mackey, medical oncologist, Cross Cancer Institute, Edmonton, Alberta. "This is reassuring for patients, and also for physicians faced with the decision of which first-line treatment to prescribe." At median follow up of 18.2 months follow up analysis of data from 611 women confirmed as hormone-receptor positive, demonstrates that Arimidex has a significant clinical benefit over tamoxifen in terms of TTP (median values of 10.7 and 6.4 months for Arimidex and tamoxifen respectively, p equals 0.022, 2 sided). Both treatments were well tolerated, however, as predicted by its pharmacology, favourable numerical differences were seen with respect to thromboembolic events and cases of vaginal bleeding in patients treated with Arimidex (4.5 vs 7.6 per cent and 1.0 vs 2.2 per cent respectively). At 18.2 months follow up, 137 patients who received Arimidex as first line therapy were known to have received second-line treatment with tamoxifen. Preliminary data on 98 of these patients revealed that 56 women showed clinical benefit (complete or partial response or long stable disease, i.e. more than 24 weeks) from tamoxifen as second-line therapy after Arimidex. Of the second and third generation aromatase inhibitors, Arimidex has the most clinical experience and largest number of patients in first-line studies where its efficacy is established. Arimidex has been shown to be more effective than tamoxifen for the treatment of postmenopausal women with advanced breast cancer that is hormone sensitive, and at least as well-tolerated. It is not yet known how Arimidex will compare to tamoxifen in early breast cancer. Arimidex and tamoxifen have different mechanisms of action, which could explain the low level of cross resistance seen in these recent studies when sequencing. This raises the important question of whether these endocrine therapies could have increased efficacy when used in combination. These questions could be answered as early as next year by the ATAC (Arimidex, Tamoxifen®, alone or in combination) study, the largest adjuvant breast cancer study ever conducted. ATAC will compare Arimidex and tamoxifen in terms of efficacy and tolerability in early breast cancer, and will also reveal if a combination of Arimidex and tamoxifen provides enhanced efficacy in the adjuvant setting. "While the role of tamoxifen as monotherapy for breast cancer has already been established, we're now moving into exciting new possibilities of where to use these new agents in the sequence of treatment and whether combination therapy is an option," adds Dr. Michael Baum, professor of surgery at University College Hospital in London, England and chairman of the ATAC steering committee. "There is the potential to improve outcomes and widen therapeutic options and next year will be a landmark for widening our understanding of these possibilities." Arimidex is approved in Canada for the treatment of advanced breast cancer in post menopausal women. Related Link: Arimidex (anastrozole).
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