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05.08.2005 – 01:02

AstraZeneca GmbH

Data Confirm Postmenopausal Women Taking Adjuvant Tamoxifen for Early Breast Cancer Remain Cancer Free for Longer by 'Switching' to 'ARIMIDEX'(TM)

    Macclesfield, England (ots/PRNewswire)

"The results of our data confirm that a switch in therapy from tamoxifen to anastrozole can help us as clinicians to help our patients live cancer-free for longer."

    Professor Raimund Jakesz

    Vienna Medical University, Austria

    Austrian Breast & Colorectal Cancer Study Group

    Data published today provide good news for the thousands of women who are currently taking tamoxifen as adjuvant treatment for early breast cancer. A prospectively planned combined analysis of two multi-centre, randomised studies, published in The Lancet, confirms that postmenopausal women already taking tamoxifen as part of their treatment for early breast cancer are able to reduce the chance of their breast cancer returning by switching therapy to 'Arimidex'TM (anastrozole).1

    The ABCSG* 8 (n = 2262) and ARNO** 95 (n = 962) Trials were similarly designed to assess whether changing treatment from tamoxifen to 'Arimidex' after 2 years was more effective than remaining on tamoxifen for 5 years. At a median follow-up of 28 months, switching to 'Arimidex' rather than staying on tamoxifen resulted in a:

    - 40% reduction in the risk of disease recurrence (HR = 0.60; p = 0.0009), and

    - 39% reduction in the risk of distant metastases (HR = 0.61; p = 0.0067).

    The ATAC*** study confirmed that taking 'Arimidex' rather than tamoxifen, for the first 5 years after diagnosis of early breast cancer, is superior in terms of both efficacy and tolerability.2 Data, from over 9,000 postmenopausal women who took part in the ATAC study, show that 5 years of 'Arimidex' is associated with a significantly reduced risk of disease recurrence (including distant disease recurrence and contralateral breast cancer). They also demonstrate a reduction in many of the serious adverse events that have long been associated with tamoxifen, such as an increased risk of endometrial cancer, deep vein thrombosis and stroke.2

    Data from these latest studies now confirm that those patients who have not had the advantage of starting their adjuvant therapy with 'Arimidex' can still gain benefit if they switch therapy from tamoxifen to 'Arimidex'.

    "The ABCSG and ARNO studies confirm that women currently taking tamoxifen should be switched to anastrozole to give them the best chance of living cancer-free for longer. It is important to note that these results apply only to those women who have successfully completed 2 years' adjuvant therapy with tamoxifen for early breast cancer. They are not applicable to patients just about to start their adjuvant breast cancer treatment," commented Professor Raimund Jakesz, Vienna Medical University, Austria, and lead ABCSG 8 trial investigator.

    All the evidence now indicates that 5 years of treatment with tamoxifen is no longer the optimal therapy for postmenopausal women with hormone-sensitive early breast cancer. The recently published update to the ASCO**** Technology Assessment on the Use of Aromatase Inhibitors (AIs) in the Adjuvant Setting support the routine use of 'Arimidex', both for newly diagnosed patients just starting treatment, and for those who have already commenced therapy with tamoxifen. The guidelines state that "...optimal adjuvant hormonal therapy, for a postmenopausal woman with receptor-positive breast cancer should include an AI, either as initial therapy, or after treatment with tamoxifen" and favour using the agent with the most data relevant to each individual clinical setting.3 'Arimidex' is the most studied of all the AIs and the only product in its class with data to support its use both for initial adjuvant therapy and for a switch in therapy in patients part way through a course of tamoxifen. Therefore, evidence-based medicine suggests, that 'Arimidex' should become the preferred choice of endocrine therapy to replace tamoxifen in both of these settings.

    "We know from the ATAC trial that we can give women the best chance of preventing their disease returning, as well as reducing the risk of many of the adverse events associated with tamoxifen, by initiating adjuvant therapy with anastrozole from the start," commented Dr. Aman Buzdar of the MD Anderson Cancer Centre, Texas. "The ABCSG and ARNO trials provide further evidence that, for women who are already on tamoxifen therapy, changing to anastrozole can significantly reduce the risk of recurrence. This confirms that anastrozole is a superior treatment that we can offer to postmenopausal women with early breast cancer and it should become the new standard of care offered to all suitable patients as soon as possible following surgery."


    1. Jakesz R, Jonat W, Gnant M et al. Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG Trial 8 and ARNO 95 Trial. Lancet, 2005; 366: 455-62.

    2. ATAC Trialists' Group. Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years' adjuvant treatment for breast cancer. Lancet, 365 (9453): 60-62.

    3. Winer EP, Hudis C, Burstein HJ et al. American Society of Clinical Oncology Technology Assessment on the Use of Aromatase Inhibitors As Adjuvant Therapy for Postmenopausal Women With Hormone Receptor-Positive Breast Cancer: Status Report 2004. J Clin Oncol 2005; 23 93: 1-11.

    Notes to Editors

    * ABCSG - Austrian Breast & Colorectal Cancer Study Group

    ** ARNO - 'Arimidex' - 'Nolvadex'

    *** ATAC - 'Arimidex', Tamoxifen, Alone or in Combination

    **** ASCO - American Society of Clinical Oncology

    AstraZeneca continues its tradition of research excellence and innovation in oncology that led to the development of its current anti-cancer therapies including 'ARIMIDEX' (anastrozole), 'CASODEX' (bicalutamide), 'FASLODEX' (fulvestrant), 'NOLVADEX' (tamoxifen), 'ZOLADEX' (goserelin), 'TOMUDEX' (raltitrexed) and 'IRESSA' (gefitinib) as well as a range of novel targeted products such as anti-proliferatives, anti-angiogenics, vascular targeting and anti-invasive agents. AstraZeneca is also harnessing rational drug design technologies to develop new compounds that offer advantages over current cytotoxic and hormonal treatment options. The company has over 20 different anti-cancer projects in research and development.

    AstraZeneca is a major international healthcare business engaged in the research, development, manufacture and marketing of prescription pharmaceuticals and the supply of healthcare services. It is one of the world's leading pharmaceutical companies with healthcare sales of over $21.4 billion and leading positions in sales of gastrointestinal, cardiovascular, respiratory, oncology, and neuroscience products. AstraZeneca is listed in the Dow Jones Sustainability Index (Global) as well as the FTSE4Good Index.

    'ARIMIDEX', 'CASODEX', 'FASLODEX', 'NOLVADEX', 'ZOLADEX', 'TOMUDEX', and 'IRESSA' are trademarks, the property of the AstraZeneca group of companies.

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