New Data Show Survival Benefit for Arimidex(TM) in Early Breast Cancer
Macclesfield, England (ots/PRNewswire)
- Replacing tamoxifen With Arimidex (TM) (anastrozole) Shown to Reduce Patient's Risk of Death by Nearly a Third
Breakthrough new data presented today show breast cancer treatment 'Arimidex' (anastrozole) is the first aromatase inhibitor (AI) to provide an overall survival benefit, compared with tamoxifen, in the treatment of hormone-sensitive early breast cancer.(1)
According to a new analysis of data presented at a leading breast cancer symposium in San Antonio, Texas (SABCS)(i), by replacing tamoxifen with anastrozole, postmenopausal women being treated for early breast cancer are not only able to almost halve the likelihood of their disease returning, but more importantly, reduce their risk of dying by nearly a third.
"For the first time, an aromatase inhibitor has shown a survival advantage over tamoxifen in early breast cancer. These studies, along with others such as the ATAC trial, confirm that tamoxifen is no longer the best option we can offer our patients. Women who have taken 2 years of tamoxifen should be switched to anastrozole at the earliest opportunity to give them the best chance of surviving their disease," commented Prof. Walter Jonat of University of Kiel, Germany, the key investigator who presented the new data at the SABCS.
Three key international trials [ABCSG 8 (n = 2262)(2,3), ARNO 95 (n = 962)(3), and ITA(4) (n = 448)](ii) were similarly designed to assess, in women already being treated with tamoxifen, whether or not replacing tamoxifen therapy with anastrozole after 2 years was more effective than remaining on tamoxifen for the full 5-year treatment period. Dr Jonat presented a meta-analysis of these three trials (n=4006) at the SABCS today. The data showed, at a median follow-up of 30 months, patients who started taking anastrozole, rather than remaining on tamoxifen, experienced a:
- 29% improvement in overall survival (HR 0.71; 95% CI 0.52 - 0.98; p=0.0377),
- 45% improvement in event-free survival (HR 0.55; 95% CI 0.42 - 0.71; p<0.0001), and
- 39% improvement in distant recurrence-free survival (HR 0.61; 95% CI 0.45 - 0.83; p=0.0015).(1)
(Event-free survival: any disease recurrence - local, contralateral or distant; Distant recurrence free survival: distant recurrence only)
These data now confirm that replacing tamoxifen with anastrozole can significantly reduce recurrence, prevent metastatic spread and ultimately save the lives of many women with early breast cancer.
"These survival data are good news. Year after year we continue to hear breakthroughs for hormonal therapies. Today's data bring us that much closer to hearing the words we really want to hear - that for some, survival is a greater possibility than ever before," stated Dallas Petroff, Executive Director of the Willow Breast Cancer Support & Resource Services in Canada.
Today's data are exciting news for the millions of women currently taking tamoxifen to prevent disease recurrence. However, it is important to remember that recent evidence and opinion have shown that women newly diagnosed with hormone-sensitive early breast cancer should be started on anastrozole as the initial hormonal treatment after surgery.(5) In the landmark ATAC(ii) trial (n=9366), women taking anastrozole for the full 5-year treatment period had a significantly reduced risk of disease recurrence (including distant disease recurrence and contralateral breast cancer), compared with tamoxifen, especially during the first 3 years following surgery, when this risk is greatest.(5) Additionally, these women suffered far fewer serious side-effects, including an increased risk of endometrial cancer, thromboembolic events and ischaemic cerebrovascular events, than those who were started on tamoxifen(5). Although anastrozole, like all AIs, increases the risk of osteoporotic fracture compared with tamoxifen, it is possible to predict which women may be most at risk of fracture and manage them accordingly. This is not the case with the more serious side effects associated with tamoxifen.
"The ATAC trial has confirmed that starting treatment with anastrozole at the earliest opportunity after surgery, and giving it for the full 5 years of treatment, is more effective than tamoxifen for the prevention of disease recurrence. This would suggest that the best place to use anastrozole is right from the start. These new data are important news for women currently taking tamoxifen who can still gain from the significant benefits of anastrozole by switching at 2 years." commented Prof. Jeffrey Tobias of University College Hospital, London, United Kingdom.
References
1. Jonat W et al. Switching from adjuvant tamoxifen to anastrozole in postmenopausal women with hormone-responsive early breast cancer: a meta-analysis of the ARNO 95 trial, ABCSG Trial 8, and the ITA trial. Abstract No. 18. San Antonio Breast Cancer Symposium 2005.
2. Jakesz, R. et al. The benefits of sequencing adjuvant tamoxifen and anastrozole in postmenopausal women with hormone-responsive early breast cancer: 5 year-analysis of ABCSG Trial 8. Abstract No. 13. San Antonio Breast Cancer Symposium 2005.
3. 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 (9484):455-462.
4. Boccardo F, Rubagotti A, Puntoni Met al. Switching to anastrozole versus continued tamoxifen treatment of early breast cancer: Preliminary results of the Italian Tamoxifen Anastrozole trial. Journal of Clinical Oncology 2005; 23 (22):5138-5147.
5. 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.
Notes to Editors
(i) SABCS - San Antonio Breast Cancer Symposium
(ii) ABCSG - Austrian Breast & Colorectal Cancer Study Group,
ARNO - 'Arimidex' - 'Nolvadex',
ITA - Italian Tamoxifen Anastrozole
(iii) ATAC - 'Arimidex', Tamoxifen, Alone or in Combination
In the UK, 'Arimidex' (anastrozole) is licensed for the adjuvant treatment of postmenopausal women with hormone receptor positive early invasive or advanced breast cancer
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.
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