ARIMIDEX indications

ARIMIDEX is widely prescribed, with over 5.9 million patient-years of experience.2

Adjuvant treatment of postmenopausal women with hormone receptor-positive early invasive breast cancer

ATAC (ARIMIDEX, Tamoxifen Alone or in Combination) trial

The ATAC trial, the largest randomised, double-blind trial of adjuvant therapy in early breast cancer to date,3 investigated the efficacy and tolerability of ARIMIDEX, tamoxifen and the combination of both.4

The superiority of ARIMIDEX over tamoxifen in the adjuvant treatment of postmenopausal early breast cancer was first established on the 33 month analysis of the ATAC trial.4 With 68 months median follow up, patients have not been followed up for sufficient time after 5 years of treatment, to enable a long term post treatment effect for comparison.1 However, with the 10 years' follow up of the ATAC trial confirms that ARIMIDEX provides both early and long-term benefits that extend beyond the completion of active treatment.4 The recommended duration of treatment for early disease is 5 years.1

No new safety concerns were identified during the 10-year follow-up analysis.4

View details of the ATAC trial design and results.

Adjuvant treatment of early invasive breast cancer in hormone receptor-positive postmenopausal women who have received 2 to 3 years of adjuvant tamoxifen

Switching trials: the combined analysis of the ABCSG 8 and ARNO 95 trials6

A prospectively planned combined analysis of the ABCSG 8 and ARNO 95 studies was undertaken.6 The median time of follow-up was 28 months. The primary endpoint was event-free survival, including locoregional recurrences, distant metastases and contralateral breast cancers.

• In patients who have already received 2 years of tamoxifen, switching to ARIMIDEX is significantly more effective than remaining on tamoxifen with respect to event-free survival at 3 years post-switch (P=0.0009)6
• Switching to ARIMIDEX led to a significant reduction in distant recurrences at 3 years post-switch (P=0.0067)6

View details of the ABCSG 8 and ARNO 95 studies

Treatment of advanced breast cancer in postmenopausal women

First-line advanced breast cancer trials—ARIMIDEX vs tamoxifen

Two large trials compared the efficacy and tolerability of ARIMIDEX and tamoxifen for the first-line treatment of postmenopausal women with advanced hormone receptor-positive breast cancer.7

A combined analysis of the 2 clinical trials (1021 patients, including 611 HR+ patients) found:

• The median time to progression (TTP) for ARIMIDEX was 8.5 months, compared to 7.0 months for tamoxifen (P=NS)

A retrospective subgroup analysis of patients with hormone receptor-positive breast cancer indicated that ARIMIDEX was superior to tamoxifen with respect to TTP (P=0.022).7

View details of the first-line advanced breast cancer trials

Second-line advanced breast cancer trials—ARIMIDEX vs megestrol acetate

In a combined analysis of 2 phase III trials, ARIMIDEX (1 mg and 10 mg orally once daily) was compared with megestrol acetate (40 mg orally 4 times daily) as second-line therapy in postmenopausal patients with advanced breast cancer whose tumours were either oestrogen and/or progesterone receptor-positive or of unknown receptor status.8

At a median follow-up of 31 months:

• Estimated median survival with ARIMIDEX 1 mg was 26.7 months, compared with 22.5 months for megestrol acetate8

ARIMIDEX 1 mg demonstrated a statistically significant survival advantage over megestrol acetate, with a hazard ratio of 0.78 (P, 0.025). 8

View details of the second-line advanced breast cancer trials

References

1. ARIMIDEX UK SmPC. Last updated 7^th Oct 2011. http://www.medicines.org.uk/emc/medicine/3845/SPC/Arimidex+1mg+Film-Coated+Tablet/

   As there may be local variations in the approved label, please consult the local ARIMIDEX prescribing information before use.

2. AstraZeneca, Data on file; ADX2810102.
3. AstraZeneca, Data on file; ADX2910101.
4. Cuzick J et al. Effect of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: 10-year analysis of the ATAC trial. Lancet Oncol 2010; doi:10.1016/S1470-2045(10)70257-6.
5. Baum M et al, on behalf of the ATAC Trialists’ Group. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomised trial. Lancet 2002; 359(9324): 2131–9.
6. Jakesz R 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): 455–62.
7. Bonneterre J et al. Anastrozole is superior to tamoxifen as first-line therapy in hormone receptor positive advanced breast carcinoma: results of two randomized trials designed for combined analysis. Cancer 2001; 92(9): 2247–58.
8. Buzdar AU et al. Anastrozole versus megestrol acetate in the treatment of postmenopausal women with advanced breast carcinoma: results of a survival update based on a combined analysis of data from two mature Phase III trials. Cancer 1998; 83(6): 1142–52.