New data from the first study of its kind, show that, in postmenopausal women whose advanced breast
cancer is both hormone receptor-positive (HR+) and HER2-positive, a
combination of ArimidexTM (anastrozole) plus Herceptin? (trastuzumab) keeps
cancer under control for significantly longer than hormonal therapy alone
(anastrozole).1 The median progression-free survival was 4.8 months versus
2.4 months, respectively. These data were presented at the 31st European
Society for Medical Oncology (ESMO) Congress today.
Around 75 percent of postmenopausal women with breast cancer are known to
have HR+ disease and are eligible for treatment with Arimidex. As many as a
quarter of these women will also be HER2-positive, which means that they
have a particularly aggressive form of cancer, with a higher likelihood of
relapse. For these particular women with so-called ?co-positive' cancers,
?Co-positive' breast cancer patients have tumour cells that both respond to
oestrogen and HER2 protein, which stimulate growth of the cancer. The
opportunity to take a combination of two highly effective anti-cancer drugs
will be a welcome addition to their treatment programme.
The data presented at ESMO today continue to highlight the current and
future potential of Arimidex in breast cancer. Arimidex was the first
treatment shown to improve upon the efficacy and tolerability of tamoxifen
in early breast cancer, resulting in significant changes to treatment
practice. Now Arimidex becomes the first treatment of its kind to
demonstrate a benefit in combination with Herceptin in advanced disease.
Arimidex in early breast cancer
Additional data presented for the first time in Europe today, confirm the
benefits of initiating Arimidex directly after surgery in early breast
cancer patients. Postmenopausal, HR+ early breast cancer patients are 26%
less likely to suffer a disease recurrence if treatment is started with
Arimidex rather than tamoxifen. Data from the mature, 68-month analysis of
the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial, show that
the majority of the recurrences seen with tamoxifen occur within the first
few years of treatment, emphasising the importance of starting Arimidex
treatment early.2
?Preventing recurrence is the primary aim of adjuvant treatment - if the
cancer doesn't come back, you can't die from it,? explained Professor Joan
Houghton, Senior Lecturer in Clinical Trials, Department of Surgery,
University College London, UK.
?In the ATAC trial, over half of the additional recurrences seen with
tamoxifen occurred within the first two and a half years of surgery. There
may still be a place for tamoxifen in early breast cancer, but these data
show us that treating women with ?Arimidex', from the outset, provides the
optimal protection against early recurrence.?
Importantly, women on Arimidex also suffered far fewer side effects
compared with tamoxifen, meaning that a significantly greater number were
able to complete their treatment.3 One of the key considerations with
using tamoxifen is that it is known to be associated with some rare, but
life-threatening side effects, the majority of which were also seen to
occur in the first few years of treatment.
-- Women who took Arimidex experienced fewer strokes, fewer DVTs and fewer
gynaecological side effects than women who took tamoxifen, over a five-year
treatment period.3
-- Women on Arimidex were four times less likely to undergo a hysterectomy
- a procedure often undertaken as a result of gynaecological abnormalities.
3
Side effects that were significantly increased with Arimidex compared with
tamoxifen were fractures and joint disorders.3 When balanced against the
life-threatening side effects of tamoxifen, the risk of fractures with
Arimidex is seen as predictable and manageable and the risk:benefit ratio
for adjuvant therapy is consistently in favour of Arimidex compared with
tamoxifen.
Professor Robert Mansel, Department of Surgery, Wales College of Medicine,
Cardiff University and member of the ATAC Steering Committee stated:
?Starting therapy with tamoxifen puts patients at risk of preventable
recurrences and avoidable serious side effects. It took a long time for us
to improve upon tamoxifen, but with the mature data we have now for
Arimidex, we know we have a more effective and better tolerated treatment
to help our patients stay free from breast cancer.?
About HR+ and HER2+ tumours:
--In HR+ breast cancer, the tumour cells carry receptors on their surface,
which respond to oestrogen and stimulate the growth of the tumour.
Approximately 75% of postmenopausal breast tumours are hormone
receptor-positive.
--In HER2-positive breast cancer, the tumours have an increased quantity
of the HER2 protein on the surface of the cells. Tumours of this type are
particularly aggressive. HER 2-positivity affects around 20-30% of women
with breast cancer.
-- Arimidex is the most comprehensively studied of all the AIs and the only
one with efficacy and tolerability data for the full five-year (median
follow-up 68 months) adjuvant setting.4
References:
1. Kaufman, B. Trastuzumab plus anastrozole prolongs progression-free
survival in postmenopausal women with HER2 positive, hormone-dependent
metastatic breast cancer (MBC). Abstract no. LBA2, presented at the ESMO
2006, Istanbul, Turkey, 29th Sept - 3rd Oct 2006
2. Houghton, J on behalf of the ATAC Trialists' Group, Initial adjuvant
therapy with anastrozole (A) reduces rates of early breast cancer
recurrence and adverse events compared with tamoxifen (T).
Abstract no 243, presented at the ESMO 2006, Istanbul, Turkey, 29th Sept -
3rd Oct 2006
3. Mansel, R on behalf of the ATAC Trialists' Group. Tolerability of
anastrozole (A) compared with tamoxifen (T): mature data in the adjuvant
setting Abstract no 244, presented at ESMO 2006, Istanbul,
Turkey, 29th Sept - 3rd Oct 2006.
4. 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, 2005; 365 (9453): 60-62.
http://www.astrazeneca.com
Herceptin
Published
Published Fri 6 Oct 2006
