MACCLESFIELD--5 Jun--PRNewswire-Asianet/InfoQuest
Evidence Drives More Clinicians to Choose anastrozole as Optimal Hormonal Therapy for Postmenopausal Women With Early Breast Cancer
AstraZeneca announced today, from the American Society of Clinical Oncology (ASCO) Annual Meeting, that anastrozole has this month become the first aromatase inhibitor (AI) to accumulate over two million patient years' clinical experience. Since the mature results from the ATAC(i) trial clearly established the superiority of anastrozole over tamoxifen in early breast cancer (1),
anastrozole has become the world's most used AI.
Commenting on this treatment revolution, Dr. Buzdar of the MD Anderson Cancer Centre in Texas said: "When deciding what's best for our patients, we look to clinical evidence and guidelines to lead our choices. Anastrozole has consistently demonstrated that it's more effective and better tolerated than tamoxifen. Guidelines are now strongly recommending the use of an AI in early breast cancer patients and anastrozole has the most experience and strongest evidence. It's not surprising then, that doctors are increasingly choosing it to help their patients stay free from breast cancer after surgery, whilst avoiding some of the unpredictable and sometimes serious side effects that they risk with tamoxifen."
Bone health in postmenopausal women taking aromatase inhibitors
In recommending the use of AIs such as anastrozole in early breast cancer, recent treatment guidelines have also highlighted that additional evidence was needed regarding the effect of AIs on bone strength. A 5-year update from the ATAC bone-sub-protocol, also presented today at ASCO confirms that, if women have a normal bone mineral density (BMD) at the outset, they can undergo a 5-year course of treatment with anastrozole without the risk of developing osteoporosis(2). These data have generated much excitement in the medical community as it is the first time that long-term data have been available on the effects of an AI on bone.
Although a reduction in BMD does occur over the 5-year course of treatment with anastrozole, the rate of bone loss slows down significantly after the first 2 years. Normal reduction in BMD associated with ageing is approximately 2-3% over 5 years; the bone loss seen with anastrozole is slightly higher (average, 6.1% in the lumbar spine and 7.2% in the hip) but is not significant
enough to lead to osteoporosis (bone loss of 15-20%). Separate data have also supported the fact that the rate of bone fracture among women taking anastrozole is comparable to the normal patient population of that age group (3,4). Clinicians who may have previously been reluctant to prescribe anastrozole, because of the unconfirmed effect on bone, can now be more confident that it not only offers their patients a significantly better chance of staying cancer-free, any side effects such as a reduction in bone strength are predictable and manageable.
Switching from tamoxifen to anastrozole
Additional data presented at ASCO today further support the benefits of anastrozole over tamoxifen. Although it is clear that postmenopausal women with early breast cancer gain the greatest benefit from starting anastrozole treatment immediately after surgery, those who have already commenced treatment with tamoxifen do not have to miss out on the superior efficacy and
tolerability of the newer drug. New data from the prospective 'Arimidex'-'Nolvadex' 95 (ARNO) study are the first data from a single trial to confirm that stopping tamoxifen and switching to anastrozole can potentially save lives(5). These data are consistent with previous meta-analysis data from three trials [presented at SABCS(iii) 2005
](6) which also demonstrated an improvement in overall survival among women who switched treatments.
"It's reassuring to know that the data for anastrozole continue to justify the confidence that we as clinicians already have in selecting it as the optimal treatment for our postmenopausal early breast cancer patients. The increasing evidence base for AIs continues to confirm that tamoxifen is not the most effective or safe drug we can offer our patients to keep them free from
recurrence," concluded Dr Buzdar.
References:
1. ATAC Trialists' Group. Lancet 2005; 365: 60-62.
2. Coleman R. Proceedings of the American Society of Oncology (ASCO), 2006. Abs 511
3. Fisher B et al. J Natl Cancer Inst 1998; 90: 1371-1388.
4. Women's Health Initiative Writing Group. JAMA 2002; 288: 321-333
5. Kaufmann M. Proceedings of the American Society of Oncology (ASCO), 2006. Abs 547
6. Jonat W. Proceedings of the San Antonio Breast Cancer Symposium, 2005
Notes to Editors:
(i) Patient years calculations: Patient takes one tablet per day and there are 365 days per year.Therefore, total tablets sold since launch divided by 365 = number of patient years
(ii) ATAC Trial: 'Arimidex' Tamoxifen, Alone or in Combination
(iii) SABCS: San Antonio Breast Cancer Symposium
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 $23.95 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 FTSE4Good Index.
'Arimidex' is a trademark, the properties of the AstraZeneca group of companies.
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SOURCE: AstraZeneca
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