Anastrozole (Arimidex) Improves Overall Survival in Postmenopausal Women with Early Breast Cancer Receiving Treatment with Tamoxifen

 Survival Benefit Demonstrated for an AI Over Tamoxifen in a Single Trial 

LUTON, UK, Friday 15 June 2007: Analysis of the entire population of a single trial has demonstrated that survival in early breast cancer can be significantly improved by switching from tamoxifen to anastrozole (Arimidex). An analysis of the 'Arimidex'-'Nolvadex 95' (ARNO 95) study, published online in The Journal of Clinical Oncology, confirms that postmenopausal women who have been taking tamoxifen as part of their treatment for early breast cancer for two years can significantly reduce the chance of their breast cancer returning by switching therapy to anastrozole.1

The ARNO 95 study, involving 979 patients, was designed to evaluate whether post-menopausal women with hormone-receptor positive early breast cancer who had been receiving endocrine treatment with tamoxifen for two years would benefit from switching to an aromatase inhibitor (AI). The study demonstrated that women switching to anastrozole (n=489) rather than remaining on tamoxifen (n= 490) experienced1: · 34% reduction in the relative risk of recurrence (HR = 0.66; p=0.049) · 47% improvement in overall survival (HR = 0.53; p=0.045) · Fewer serious adverse events (22.7% v 30.8%) (OR = 0.66; p=0.0065)

"This new study is the first individual aromatase inhibitor trial showing a benefit in overall survival in the whole of the study population. The result is particularly striking in that this was a substantial group of patients with a relatively good prognosis (74% node negative). The reason that this result is so important is that improvement in overall survival is the biggest prize of all," said Professor Jeffrey Tobias, Consultant Oncologist and Professor of Cancer medicine, University College London. "These data confirm that women who have not had the advantage of starting their adjuvant therapy with an aromatase inhibitor and are currently taking tamoxifen should be switched to anastrozole, to give them the best chance of living cancer-free for longer. In my view women with hormone-receptor positive early breast cancer should be offered the opportunity to receive an aromatase inhibitor like anastrozole immediately after surgery and chemotherapy to provide the best protection against their cancer returning."

Anastrozole cuts recurrence when used as initial adjuvant therapy

These data reinforce the efficacy and tolerability benefits of anastrozole over tamoxifen seen in the ATAC (Arimidex, Tamoxifen, Alone or in Combination) study, which compared 5 years initial adjuvant therapy with anastrozole versus 5 years tamoxifen, and showed that prescribing anastrozole from the start significantly reduces the risk of recurrence. There is a 26% reduction in the risk of recurrence compared with tamoxifen, meaning that 1 in 4 recurrences are prevented by using anastrozole instead of tamoxifen at the start of treatment, when the risk of recurrence is highest.2,3,4,5

Furthermore, data from ATAC show that the majority of the recurrences and also of the serious adverse events associated with tamoxifen occur within the first 2.5 years of treatment, emphasising the importance of using the treatment that is more effective and better tolerated from the outset. Anastrozole remains the only AI to have demonstrated a superior risk:benefit profile compared with tamoxifen over the full 5 year treatment period and beyond, and should establish anastrozole as the emerging gold standard of care for postmenopausal women with early breast cancer. 2

ARNO 95 Trial Design · A prospective, randomised, open-label, parallel group, multi-centre study to assess differences in efficacy and safety between postmenopausal women with hormone receptor?positive breast cancer who switched from tamoxifen (20 or 30mg/d taken for 2 years) to ?Arimidex? (1mg/d taken for up to an additional 3 years), and those who continued to receive tamoxifen (20 or 30 mg/d taken for up to an additional 3 years).

AstraZeneca · 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 $26.47 billion and leading positions in sales of gastrointestinal, cardiovascular, neuroscience, respiratory, oncology and infection products. AstraZeneca is listed in the Dow Jones Sustainability Index (Global) as well as the FTSE4 Good Index.

ARIMIDEX is a trademark, the property of the AstraZeneca group of companies.

Therapeutic indications of all AIs: · Anastrozole (Arimidex), AstraZeneca: Treatment of advanced breast cancer in postmenopausal women. Efficacy has not been demonstrated in oestrogen receptor negative patients unless they had a previous positive clinical response tamoxifen. Adjuvant treatment of postmenopausal women with hormone receptor positive invasive breast cancer. Adjuvant treatment of early breast cancer in hormone receptor positive postmenopausal women who have received 2 to 3 years of adjuvant tamoxifen. · Letrozole (Femara), Novartis: Adjuvant treatment of postmenopausal women with hormone receptor positive invasive early breast cancer. Treatment of early invasive breast cancer in postmenopausal women who have received prior standard adjuvant tamoxifen therapy. First line treatment in postmenopausal women with advanced breast cancer. Advanced breast cancer in postmenopausal women in whom tamoxifen or other anti-oestrogen therapy has failed. Pre-operative therapy in postmenopausal women with localised hormone receptor positive breast cancer, to allow subsequent breast-conserving surgery in women not originally considered candidates for breast-conserving surgery. Subsequent treatment after surgery should be in accordance with standard of care. · Exemestane (Aromasin), Pfizer: Indicated for the adjuvant treatment of postmenopausal women with oestrogen receptor positive invasive early breast cancer, following 2-3 years of initial adjuvant tamoxifen therapy. Aromasin is indicated for the treatment of advanced breast cancer in women with natural or induced postmenopausal status whose disease has progressed following anti-oestrogen therapy. Efficacy has not been demonstrated in patients with oestrogen receptor negative status. Previously, the IES study has demonstrated an overall survival benefit for exemestane in only hormone receptor positive /unknown patients.6

For further information, or to arrange an interview with a breast cancer specialist or patient, please contact Joanne Wunder, Ogilvy PR Tel: 020 7309 1065 Email: joanne.wunder@uk.ogilvypr.com

OR

Stephen Cull, AstraZeneca UK Ltd Tel: 01582 836344 Mobile: 07825 530052 Email: stephen.cull@astrazeneca.com

References: Kaufmann M, Jonat W, Hilfrich J, et al. Improved Overall Survival in Postmenopausal Women With Early Breast Cancer After Anastrozole Initiated After 2 Years of Treatment With Tamoxifen Compared With Continued Tamoxifen: The ARNO 95 Study. J Clin Onc 2007 (Early online publication) Http://jco.ascopubs.org/cgi/doi/10.1200/JCO.2006.08.8054 ATAC Trialists' Group. Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of five years' adjuvant treatment for breast cancer. Lancet 2005; 365 (9453): 60-62. Early Breast Cancer Trialists? Collaborative Group. Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials. Lancet 2005; 365: 1687?1717. ATAC Trialists' Group Comprehensive side-effect profile of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: long-term safety analysis of the ATAC trial. Lancet Oncology 2006; 7 (8): 633-643 Saphner T, Tormey DC and Gray R. Annual Hazard Rates of Recurrence for Breast cancer After Primary Therapy. J Clin Onc 1996; 14: 2738-2746 Coombes RC. First Mature Analysis of the Intergroup Exemestane study. Abstract Number LBA527, 2006 ASCO Annual Meeting

 

Posted: June 2007

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